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topic: Steve Pearson (30 articles)

2022 USHPA Election »

Wed, Oct 12 2022, 12:52:28 am GMT

Steve Pearson

Steve Pearson|USHPA Election 2022|Jamie Shelden|Paul Voight|Matthew Taber|Tiki Mashy|Bill Hughes

Vote for veteran BOD members:

Please check your email for the USHPA election ballot. For those of you who might be undecided, please consider those who have contributed so much to our community and association over many years: Jamie Shelden, Paul Voight, Matthew Taber, Tiki Mashy and Bill Hughes. We need your votes!

I guess it all comes down to experience and previous contributions. The work of USHPA evolves from grinding deliberations in committees rather than wholesale proclamations of change (directors only approve the work of committees). It's so easy to break what we have and much harder to restore it. Even the most well-intentioned and executed big ideas, like self-insurance and the governance proposal, have resulted in unforeseen consequences with significant damage. I favor a path of continuous incremental improvement, where we identify and fix specific and well-defined issues with a large consensus of support from all stakeholders rather than strong-arming short-sighted and self-interested policies. Big-new ideas more often fail, as anyone who has been around knows. Understanding and embracing the constraints of our diverse leadership and membership is difficult and frustrating at times. *None of us get what we want*. These 5 individuals are long-term participants and contributors in the committee process and appreciate both the opportunities and limitations of the bureaucracy. I hate politics and bureaucracy and I'm not good at it either. I was blessed with 45 years in a partnership without these dynamics and where it was so much easier to get things done. The best directors are those with a large well of experience in community development, with diverse ideas and passion for implementing them, but also the ability to listen, support others, and compromise. It only takes one disruptive person to suck the oxygen and derail all progress.

If you read my reply to Davis, you would understand that directors don't have any mechanism to advance their ideas except through the committee process. That requires a lot of work, compromise, listening and consensus building. The people that I identified in my initial post are the only ones with committee experience. Beyond that, they *each* have many years of participation on multiple committees and had advanced to the leadership chair position based on the support of their peers, before I even became a director.

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Wills Wing Party

Wed, Mar 19 2003, 9:00:05 pm GMT

beer|Chris Wills|Florida|history|landing|Pat Denevan|Rob Kells|spin|Steve Pearson|Wills Wing

Rob Kells <Rob@WillsWing.com> writes:

Mitch should be arriving in Florida with the truck and trailer sometime Monday (the 24th). Based on the strong response, we have upped the ante a bit. Mitch and I will be setting up twenty two demo gliders on Tuesday morning, including two of each size of the U2.

My partners, Steve Pearson, and Mike and Linda Meier will arrive mid week.

Chris Wills will arrive Friday night to spin yarns about the very early days of bamboo and plastic. Pat Denevan (https://OzReport.com/Ozv6n210.shtml) will do a free Launch/Landing clinic lecture from 9:00 to 10:00 on Saturday morning.

Saturday night we may have a surprise demo flight, beer, followed by some dinner in the big top, a brief 30 year history slide show, more beer, and a hopping band.

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Aero’s down tube drag »

Thu, Dec 12 2002, 5:00:03 pm GMT

Ron Gleason <xcflying@earthlink.net> writes:

Have you seen this? http://www.justfly.com/gliders/stalkeruprightcharts.htm

Sounds interesting and I would like to understand more. I wonder how the ATOS C compares?

I tried the URL, but while the page was there it didn’t really work that well. GW sent me the charts that were missing and the table of the data:

Source Data for Charts

Length

Uprights chord, b, m

S upright, m

Cd

Cd*S upright

Speed, m/s

Upright drag force, kg

Delta, %

AEROLA Carbon

1.48

0.069

0.10212

0.03

0.0031

20

0.075

Wills Wing

1.48

0.076

0.11248

0.035

0.0039

20

0.097

29

Bautek

1.48

0.053

0.07844

0.08

0.0063

20

0.154

105

Finster Walder

1.48

0.049

0.07252

0.357

0.0259

20

0.637

745

For 120 kg take off weight, 72km/h speed,15 glide ratio, glider drag force is

8

kg

If glider with AEROLA carbon uprights at speed 72km/h has glide ratio

15

with WW uprights you will have glide ratio

14.9

with Bautek uprights you will have glide ratio

14.7

with FW uprights you will have glide ratio

13.2

I am trying to get more information from G.W. I really question the nominal 15:1 glide at 45 mph.

In the mean time I asked Steve Pearson at Wills Wing about the claims made in the charts, especially as they are compared with the WW down tubes. He wrote:

It's impossible to make any kind of informed decision about the relative performance of the Stalker downtubes based on the published information. The link that you forwarded doesn't have any wind tunnel test data, and there's no indication that they even retested our section. Without a side by side comparison in the same tunnel, over a wide angle of attack and Reynolds number range, the information is completely speculative.

It's trivial to design a section that has better performance than the Slipstream at 20 m/s, at low angle of attack, without any other constraints. In fact, any number of NACA sections will do the job. Our wind tunnel tests show that the Slipstream performs 10% better and matches the Stalker's claimed Cd by simply sanding of the trip. The problem is that doubles the drag at lower speeds.

We're not always gliding at 45 mph and (unless you're flying a Swift) you're nowhere close to 15:1 at anything much beyond best glide speed. The advantage of the Slipstream profile is not the minimum drag coefficient at high speeds, but the extremely wide angle of attack range--especially at lower Reynolds numbers--with low drag coefficients. Would you trade.1 point better L/D at 45 mph for.5 point lower L/D at 30 mph?

Another important consideration is the structural performance (column strength) of the tube. Most of the drag advantage in the Stalker calculations is based on smaller size. Obviously, a smaller Slipstream tube would also have less drag. A lower strength tube is probably desirable for the smaller (non structural) rigid wing control frame. I'd be surprised if the new Atos composite downtubes don't have less total drag than a Slipstream also, but there's no chance that they could meet our structural standards.

As far as I know, our carbon bar is the only bar that has been certified on a flexwing. The Talon 150 was load tested to a 3 sec average load of 1700 lb and a peak load of over 2400 lb at 70mph with a Slipstream bar, without failure.

Finally, there's the issue of demonstrated performance. Manfred and many other top comp pilots from Icaro, Moyes, and even Aeros have flown with the Slipstream bars for years and (as you know) the 1st two 400 mile flights were Slipstream equipped.

I'm certainly not suggesting that it's not possible to design a better profile than the Slipstream--it's been out for 4 years and we even published the wind tunnel results http://www.willswing.com/articles/Article.asp?reqArticleName=MeasureDTs - -but there's more to it than making a couple of bar charts in Excel.

Find out more about this at OzReport.comOzv5n40.htm.

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Airblade ⁢ATOS »

Sat, Jun 29 2002, 5:00:06 pm GMT

ATOS|carbon fiber|Manfred Ruhmer|Steve Pearson|Valerio Canestrelli|Wills Wing

valerio canestrelli «airblade» writes:

The Airblade Full Carbon control bar for my small Atos features:

- Full carbon fiber and Hi temp. epoxy, hand layered in the molds (that I built too);
- 2 mm. short arrangement, front-rear wires;
- " World Carbon Team " Airfoil, under license from Wills Wing (scaled down to 68 mm. X 16.5 mm. instead of 76 mm. x 19 mm.);
- 2 mm. flap rope, inside the basetube ;
- Airblade finish !

Unfortunately the work required to build this frame is too much, so it is not for sale !

I would like to thank Wills Wing (i.e. Steve Pearson) for the airfoil and all the support that he gave me!

The front and rear wires are fixed to the upper half of the downtubes, like Manfred did (before the new FAI rules). We don’t have this limitation on the cantilevered wings

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The Wallaby Open blows up

Wed, Apr 17 2002, 5:00:00 pm EDT

Belinda Boulter|Gary Osoba|JC Brown|Manfred Ruhmer|Mike Barber|Steve Pearson|weather

Belinda Boulter|cart|Gary Osoba|JC Brown|Manfred Ruhmer|Mike Barber|Steve Pearson|weather

Belinda Boulter|cart|Chris Zimmerman|Gary Osoba|JC Brown|Manfred Ruhmer|Mike Barber|Steve Pearson|weather

Belinda Boulter|cart|Chris Zimmerman|Gary Osoba|JC Brown|Manfred Ruhmer|Mike Barber|Oleg Bondarchuk|Steve Pearson|weather

Belinda Boulter|cart|Chris Zimmerman|Gary Osoba|JC Brown|Manfred Ruhmer|Mike Barber|Oleg Bondarchuk|Steve Pearson|weather

There was a complete breakdown of the Wallaby Open competition today when a decision was made without a deep breath being taken before hand. Everyone involved deeply regrets this significant error in judgment. Human beings are just so driven by their emotions, and likely their lack of sleep.

The weather forecast continues to be the same (here’s Gary Osoba’s take on it):

Looks very similar to the last few days, maybe not quite as big a chance for precip.

11amcb maybe around 1800' light lift. Surface wind e 5 and ese 10 aloft

2pmcb maybe around 3300' moderate lift. Surface wind e 5-8 and ese 10-12 aloft

5pmcb maybe around 3000' light to moderate lift. Surface wind ene 5-8 and e 10-12 aloft.

The task committee calls a 65 miler with a 10 mile start circle radius for the flexies and 5 miles for the rigid wings. It’s great that we are doing tasks together and also great that we have to go the extra mile (in this case 5) to catch up with the flexies.

We’re thinking that the day could over develop and we want to get everyone out on the course line early, so we call a one and only 12:15start time with an 11 AMlaunch time. The operation here is so efficient that there is no problem getting almost everyone in the air within ½ hour. That will give everyone time to make it out ten miles.

With the early start time folks are already in the launch line at 11 AM, and there are tugs waiting. They start popping pilots out of here in a big hurray.

Francoise Mocellin in a WW Talon has her nose way way too high on the cart (she’ll start stalled). We’ve given up telling pilots that they have to have a cart that puts their nose at the proper attitude, because they are told by others to ignore us. This happens again and again.

Of course, she comes off the cart veering to the right with little control of the glider and gets too high right away before she gets it under control. The tug pilot gives her the rope and she lands safely. She finds a better cart for her second flight.

There is one other way to solve the problem (Talon’s have this problem because their down tubes are so long) which is to not allow the tug to pull the cart, but rather to have the tug pull you until you are way over the control bar and then your tail swings up off the cart and the nose comes down to make for a non stalled angle of attack. This is a bit trickier, but it does allow the confident and skilled aerotow pilot to take charge of their own tow.

Other than this continual problem the launch sequence is rapid fire and most of the flex wings get up and out of there right away. We rigid wing pilots hold back a bit to give our brethren the opportunity to get to their start circle a bit further away. We’ve only got to make five miles in forty five minutes, so it isn’t a big sacrifice.

Given that it is so early in the day the lift is light, but cloud base is already pretty high, 3,500’. I’m just staying in whatever lift there is because there is no big hurray to go anywhere as we wait for the start time.

As 12:15approaches all the rigid wing pilots are up together at cloud base at 5 miles to the south of the Ranch near highway 27 creeping up wind a bit to the east. We can’t see the flex wing pilots as they are five miles further south in their own gaggle. Some have gone 11.1 miles south of the Ranch to get up a cloud and will dive back to the start circle to start the race.

The clock ticks and we are pulled in keeping out of the clouds and heading for the BokTower. It is a big race with only the 12:15start time, so whose ever is in front at the moment is winning the race. The view is great as there are scattered cu’s every where with lots of sun shine to heat up the ground below.

Off to our right we notice the flex wing pilots. Felix comes on the radio and says that it looks like they are making the signal that the day is called. I can not believe this as the day looks absolutely perfect.

I radio to Belinda to check right away and see what’s up. Then JC Brown’s voice comes on the radio announcing that the day has been called. We see twenty or so flex wings low to our right coming back toward the Ranch and trying to scratch up. Unbelievable.

Manfred and Oleg don’t fly with radios (you should do this too if you want to be like them) and continue racing out in front of all the flex wings. Steve Pearson is in the same boat. Mike Barber and Chris Zimmerman continue along the course even though they know that the day has been called.

I fly right back to the Ranch and go to find out what happened. The day looked perfect and it is very unclear what was going on. We did see a bit of rain and virga near the location of the flex wings, but it is the only rain in the sky and it looked so light that it is hard to believe that this was the issue.

It turns out that Gerolf called on his radio and had his driver get JC Brown to come over to the van and speak with Gerolf on the radio. Gerolf told him that it was raining hard and raining on the course line and that if he was going to call the day he needed to call it now so that all the pilots could be informed visually if they didn’t have radios. JC immediately cancels the task.

No other pilot in the air is contacted about the conditions to confirm Gerolf’s observations. JC doesn’t contact the safety director nor the safety committee about calling the task for safety reasons. Because of one pilot’s feelings and observations and one meet director’s immediate and not properly considered response to the expressions of those feelings and observation, a perfectly beautiful day of competition flying is lost.

Many flex wing pilots are completely shocked by the task cancellation. They felt that the rain was minimal. They didn’t see the problem as Gerolf experienced it.

Manfred and Oleg race into goal only to find that there is no goal line and every one is at lunch. They are very unhappy about the turn of events.

The latest scores should be available at: http://www.elltel.net/peterandlinda/Wallaby_Open_2002/Wallaby.htm

Wallaby Open – rain, rain, rain

Sun, Apr 14 2002, 2:00:00 pm EDT

Felix Ruehle|Gerolf Heinrichs|Steve Pearson|Wallaby Open 2002|weather

The forecast for Sunday was for 60% chance of rain. Given the premature calling of the day by the safety committee on the first day, we are committed to flying if the weather will permit it. We are also committed to maximum flexibility so as not to call the day before any pilots get in the air if it looks possible.

Unfortunately the rain comes in strong as though it was June or July. Huge cu-nimbs form and it dumps big time. The task committee finally calls the day at 2 PM. Maybe tomorrow, maybe Tuesday.

Tonight we will hold the discussion with Steve Pearson, Felix Ruehle, and Gerolf Heinrichs on aerodynamics of flex wings and rigid wings, especially with respect to the DHV pitch test, tucks, and tumbles.

Wallaby Open scores will be found at: http://www.elltel.net/peterandlinda/Wallaby_Open_2002/Wallaby.htm

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WW Talon with variable reflex

Thu, Apr 11 2002, 6:00:01 pm EDT

Jim Lee|Rob Kells|Steve Pearson

Jim Lee|Rob Kells|Steve Lee|Steve Pearson

Rob Kells and Steve Pearson have brought three new prototypes to the Wallaby Open. They all have variable reflex geometry that raises the trailing edge of the root section higher when the VG is pulled on. The pilot has a separate cord (in the opposite corner or the control from the VG line) that allows him/her to vary the mix between VG and reflex.

The reflex is activated by thin cables above the upper surface of the wing that pull the trailing edge up at the battens. One prototype has four cables per side, one three and one two. See photo:

The battens have a weaker non aluminum section near the ends that allow them to bend at the inflection point for the reflect section of the trailing edge. Strings on the inside of the sail are attached to pulleys on the cross bar. See photo:

The point is to tune the glider so that it climbs best when the battens are not being bent at all. Normally flex wings have their sails designed so that the trailing edge acts like a bit of a flap. Then as you pull on the VG, the flap goes away.

Variable reflex also allows you to reduce your sprog setting. The reflex is taking care of the pitch moment just like it use to on king posted gliders.

Jim Lee, Steve Pearson, and Rob Kells will be flying the prototypes. Jim Lee flew the one with four variable battens on a side and said they he could out climb every one.

Aerodynamics – tucks and tumbles »

Fri, Apr 5 2002, 6:00:06 pm EST

Aerodynamics|Felix Ruehle|Gerolf Heinrichs|Rob Kells|Steve Pearson

Gerolf Heinrichs and Felix Ruehle have agreed to make short presentations on the aerodynamics of hang gliders just before the start of the Wallaby Open, or on a day that gets blown out during the meet (if that happens). Then the floor will be opened up to discussion and questions. Steve Pearson will be here, as well as Rob Kells, and many other knowledgeable pilots so I’m sure that we can get a free flowing discussion.

I’ll report on the results of any of the discussion, so that Oz Report readers won’t miss out.

Tucking articles

Mon, Feb 18 2002, 12:00:01 pm EST

Steve Pearson

Steve Pearson sent me a few articles on tucking referred to in his previous article. You can find them up on the web at http://www.davisstraub.com/Glide/garyvalle.pdf and http://www.davisstraub.com/Glide/hewittphillips.pdf.

Tuck issues

Wed, Feb 13 2002, 12:00:02 am GMT

Gary Valle|Mike Meier|Steve Elkins|Steven "Steve" Pearson|Tom Price|USHGA BOD

I had an opportunity to speak with Steve Pearson the designer at Wills Wing at the recent USHGA BOD meeting. I've had a number of opportunities to speak with Steve over the last few years and I always find my time well spent and I come away enlightened about a particular issue.

Steve pointed out that a great deal of relatively sophisticated analysis of hang glider and flying wing stability was done as much as 25 or more years ago, and that this analysis is applicable to any current concerns about tucking or tumbling, and should serve as a starting point in any attempt to develop theories about our current problems in this area. In particular we should review articles by Gary Valle, Tom Price, Hewitt Phillips, R.T.Jones who have contributed immensely to our understanding of this phenomenon.

Steve said that in the past Mike Meier had conducted a survey of hang glider tucks and tumbles in an effort to determine if there were common design or test result factors that could explain them and help hang glider designers overcome the problems. Within the class of high performance gliders, the data did not seem to indicate any correlation between design factors or test results and tumble frequency, and thus didn't provide much guidance to designers.

Recently it seems that a change may have occurred. Second generation and later topless flex wings seem, in recent years, to have a better record with respect to tucks and tumbles than the previous generations of advanced king posted hang gliders. It's difficult to quantify this, because in the history of the sport there have been periods of time when tumbles have been more or less frequent, without any obvious changes in design.

Steve wasn't confident that he had a good explanation for the apparent recent improvement in the record of topless gliders. On the other hand, he thought that the improved safety record might be related to a maintenance issue with king posted gliders and reflex lines.

Both Wills Wing and Bautec had earlier found that when the trailing edges of the sails shrink as they do over time, the reflex lines get loose and don't provide for reflex for dive recovery. When they tested older HP gliders their pitch stability was terrible.

There is both a report and a service bulletin posted on the Wills Wing web site http://www.willswing.com/launch.asp?theCategory=support&link=frmSupportPage.asp 'Reflex Bridle Adjustment and Maintaining Pitch Stability' It might be the case that the topless glider is more likely to stay within its design specifications because the reflex provided by the sprogs doesn't change as the sail shrinks. The same design factor is inherent in the design of rigid wing hang gliders.

One king posted glider for which Wills Wing has no record of any tucks or tumbles is the WW Falcon. Pilots generally think of this class of low aspect ratio glider as not being subject to tumbling, however, in the mid seventies tumbling was a serious problem on a wide range of gliders with very similar aspect ratios. What is interesting, however, is that the Falcon has relatively weak stability on the test vehicle at high speeds in comparison to either a topless flex wing or, presumably, a rigid wing (though it has similar, and perhaps better stability at low speeds).

Based on the safety record of the Falcon, Steve thinks that it's probably reasonable to conclude that other factors like pitch damping and stall behavior may be as important as pitching moment to overall glider stability. He said that vehicle and flight tests of a tail attached to a flex wing glider at Wills Wing indicated that it did not necessarily represent an easy way to improve the pitch stability of a flex wing without incurring other compromises. He felt that these test results would not necessarily be applicable to rigid wing hang gliders with their higher aspect ratios and consequentially lower downwash near the root.

He felt that tails that were attached right to the keel would be less effective, as they would be in the downwash, compared to tails that were T-tails and raised up above the keel and further away from the downwash. Steve said that the increased pitching damping contribution from the tail may be equally as important as the increased stability coefficients, i.e. slowing the rate of rotation.

He also stated that theory and speculation are not adequate to predict with confidence the statistical incidence of pitch-overs and tucks of a given model. (For example, compare the safety record of the Exxtacy to the Atos). He also pointed out that it is known that many flex wing gliders are considerably stronger than they need to be at a minimum to pass HGMA and DHV certification and that the carbon fiber cross tubes/spars on topless flex wing gliders appear to be much more durable and damage resistant than the carbon fiber d-cells that are found on rigid wings. (BTW, WW static tests each of their carbon fiber spars. 1 in 100 fails with no obvious flaw.)

Rigid wings, both because they are more rigid and because they are capable of accelerating very quickly to very high speeds, may offer a reduced structural margin in extreme circumstances. Steve pointed out the HGMA uses a 150° load test (basically you attach the glider to the truck with its back into the wind and tail down 30° and run it up to 32 mph). The DHV doesn't use this test.

The test is designed to simulate the loading that would be experienced after 180° of pitch down rotation during a tumble, which has been the more common issue of concern, at least with the HGMA, over the last 25 years. (The test does not simulate the loading in a tuck, which typically happens at a much higher speed). Since none of the rigid wings certified so far have been certified to he HGMA standards, it's not clear how they would perform in this test.

Finally, he stated that it is likely that any hang glider would be destroyed in an accelerated, high speed tuck, one like mine. He felt that at very high speed, the wings could fail without significant negative loading from torsion and drag loads alone. He felt that it was unlikely that my glider actually experienced a significant negative load during the event, because I had reported that the glider apparently failed before I hit the keel.

Without the mass of the pilot "attached" to the center of the glider, any positive or negative aerodynamic loads would be expected to be distributed over the structure relatively evenly, in such a way that it is unlikely there would be a high enough load to cause a failure.

Steve Pearson wasn’t the only one who was thinking about tucks. Steve Elkins writes:

In my 12 years of being involved with the pitch testing of hang gliders, neither I nor anyone else involved in UK pitch testing has ever seen, or heard, of a hang glider with suspect pitch stability (i.e. one that has tumbled or otherwise given rise to stability concerns) that has subsequently passed the pitch test.

Of course, given Felix’s tests at DHV of the ATOS-C, it looks like this is a first for Steve. He also writes:

However if you are flying a glider with a C of A that is within spec, there's no evidence that you need to rush out and fit a tailplane.

Seems like a lot of things are up in the air.

Another writer sends this in:

I have no axe to grind about tailplanes, but have always been aware that as we fly gliders with higher aspect ratio, hence narrower chord for a given area, we must be more prone to tucking and tumbling (I am an engineer, but not a hang glider or sailplane designer or anything like it, so its slightly more than just a gut feel)) and we put our trust in the designers of our aircraft and the test procedures for making sure that they are safe.

To be a bit more technical, again Martin Jursa, "The essential parameter determining the tumbling ability is the ratio between mean chord/Center of Gravity depth, the smaller this ratio …the easier the glider will go upside down.” It’s obvious from this that for a given wing area a glider with an aspect ratio of 12 to 1 will have about a 20% disadvantage over one with a 7.6 to 1 for the same Center of Gravity distance.

Moving on to the C of G issue, we need to explain what needs to happen when the glider's AoA suddenly becomes negative. The gist of it is that the addition of the pilots weight moves the gliders C of G downwards, this improves the stability of the glider from the test rig certification values at positive angles of attack, but worsens it at negative angles of attack particularly in the -5 to -10 ° area.

The more forward the pilot can move his weight under these conditions the smaller the adverse effect becomes until, if sufficiently far forward,the glider won't tuck or tumble. Hence the importance of being able to hold onto the bar and getting into the safety position. On stable gliders it is only necessary to pull in a little to achieve this, on more marginal machines pull in more!, but to do this you must keep hold of the bar and so on.

What I can see coming out as a result of your incident and the statement by AIR that the glider was within "DHV as tested specification", which is what I construe them publishing the inspectors report is meant to imply, is that the testing criteria used by our sport to regulate the safety of our gliders is suspect. It may be adequate for tailless gliders of a certain configuration (what are the limits) but those that fall outside this probably require extra study.

Bjørnar Ryeng <bjornar@intime.no> writes:

Also gliders (sailplanes) can definitely go inverted in strong turbulent air. I was almost inverted in an old K8 when I was relatively new to the gliding and going for some waves in strong headwind (ehh… Relatively strong - I was flying a K8). The glider recovered through a "half loop" from some 20° past vertical. If it had continued I would have pushed carefully and rolled it back from inverted instead. Except from a lot of sand and shit in my eyes and hair I was fine.

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Wills Wing's new aluminum faired base tube

Thu, Nov 15 2001, 4:00:01 pm EST

carbon fiber|Ken Howells|Steve Pearson|Wills Wing

This week, Ken Howells at Wills Wing (www.willswing.com) sent out an announcement of their new faired aluminum base tube that fits right in with their cool hardware and their Slipstream downtubes. Haven't seen something like this before I wanted to get some feeling from Steve Pearson if WW knew how well this base tube compared with their existing carbon fiber base tube. And, just how much reduction in drag we could expect. Here's what Steve had to stay.

 

 

Steve Pearson «Steve» writes:

Outside of the handgrip area, the carbon basetube has the same section and trip as the carbon downtubes that we tested in Stuttgart. As you may remember, those results showed less than 10-20% of the drag of a round tube (depending on Reynolds number and angle of attack). The handgrip area is thinner that a Finsterwalder type tube but it's untripped. I'm guessing that the total drag in the grip area is 70% of a round section. 24 inches of the 54 over all length are in the grip area. [(24 * .7) + (.2 * 30)]/54 = .42, so I'd say that the drag has to be less than 50% of a round tube.

Our wind tunnel tests showed that an untripped Slipstream carbon tube had very high drag values until high speeds (45 mph). The Freeman tube is a thicker, higher drag section than the Slipstream and is untripped. Interestingly (but consistent with analytical results) the Slipstream untripped tubes have slightly lower drag at high speeds (60 mph) than the tripped section. Speed gliders could sand off the trips for marginally better performance, however at speeds less than 45 they'd be taking a BIG performance hit.

We don't have wind tunnel results for the aluminum speedbar. It's a modified Slipstream (with trip) section with the rear edge truncated in a large radius for a nice grip. I think it's more comfortable than the carbon grip. Rob and I had a chance for a 3-mile performance comparison the other day--he was flying a non-Mylar Talon 160 with the aluminum straight base tube and I was on a Mylar Talon 140 with a standard carbon basetube. We grouped up with him 30 ft above and behind. It wasn't until 2 miles into the glide and I'd picked up the speed to 45 that he moved off to the side. Just considering the glider difference, I'd expected to see him fall away sooner so the aluminum basetube can't be hurting too much.

The aluminum basetube is completely interchangeable with the carbon basetube. Of course the corner brackets are completely different because they have to blend from the 3in cord Slipstream to the 1.9in cord basetube. If you continue to fly with the WW Atos bar, I could make an interchangeable aluminum basetube for you by adapting a set of the GB fittings that were originally designed for a straight Bautec tube.

Wills Wing control frame everywhere

Thu, Aug 2 2001, 11:00:02 am EDT

Steve Pearson|Wills Wing

Steve Pearson «Steve» writes:

I've enclosed a few pics of the Atos/Slipstream control bar retrofit. We are a short staffed trying to keep up with Talon orders, but I finally managed to fit a bar on Bruce B's Atos. It looks really nice and folds up between the Dtubes like the std bar. The basetube has pip pins at both corners so you can completely remove it. The angles are optimized for the Atos control bar rake so it should perform noticeably better than our hacksaw retrofit at the Wallaby Open of the standard Talon type fittings. Bruce is leaving for the Nats on Monday evening and, if you are interested, I'll try to send an extra bar with him for you to evaluate.

 

 

They are available now for both Atos' and GBs. The retrofit includes all companion hardware and wires. Backorders are running about 3 weeks. The Atos version retail price is $750 and is available direct from WW or though WW dealers. Flight Design pilots should order through Mike Eberle or FD authorized dealers.

Kari thanks Moyes

Mon, May 21 2001, 3:00:04 pm EDT

Florida|Kari Castle|Ken Brown|Rob Kells|Steve Pearson|Wills Wing

Kari Castle «karicastle» writes:

Thank you Moyes Australia and USA!

Vicki Moyes and Ken Brown made it possible for me to compete in Florida on the state of the art Moyes Litespeed 4 . Thanks to them I wasn't without a glider going into the last two competitions that would count towards making the US National Team. The competition was fierce with over 100 pilots and many of the top pilots from around the world.

The LS4 provided me with enough performance to keep up with the big boys and finish in the top 10 at the Flytec Championships. Needless to say I was stoked and grateful for their generosity. With their help and that of my current sponsor, Wills Wing, I have finally qualified for the US National Team (#5 ranked) that is heading for Spain in June. These are what dreams are made for. Thank you!

(editor's note: Kari did very well on her Litespeed, much better than on the Fusion. She did have a problem with a right turn in the glider that caused her a few problems competing. It had to get to her so fast that it hadn't been test flown. Bob Mcfee bought the glider and is still working to get the turn out of it. Sometimes this happens in flex wing production.

It's great when two manufacturers want you on their team. Both Moyes and Wills give great support, although nothing can top sending Rob Kells and even Steve Pearson for a few days to the Florida meets.)

Story of the double record flight

Tue, May 15 2001, 3:00:01 pm EDT

carbon fiber|Felix Ruehle|Florida|Mike Barber|Peter Radman|record|Steve Pearson|Wallaby Ranch

On Wednesday everything changed in Florida. For over a month we had had wind out of the east. After the Florida competitions The wind blew hard out of the east for two weeks and we didn't have any flying. Then a week ago Thursday, the winds finally calmed down and we were once again able to get into the air.

Still the air wasn't all that pleasant. Many pilots noted that it was "choppy" or "rolly." While the winds were light and there was moderate to good lift, its texture didn't feel quite right.

On Wednesday of this week the winds started finally coming out of the west and the texture of the air changed dramatically. For me the air now felt like the air that I had come to Florida for. No longer was I continually jarred about. It was smooth and a compete joy to fly in.

The Thursday two pm winds are forecasted to be out of the west, but the blue on the eastern half of the state shows that they will be less than 5 mph, due to the east coast on shore flow.

The area of convergence and light winds increases later in Thursday afternoon and moves further west over Wallaby Ranch.

The thermals weren't necessarily big and fat, in fact there were plenty of edges to them and you could get tossed around a bit. But no longer was there this continual hammering of your glider. Flying had once again become an enjoyable activity and not an ordeal to master.

Wednesday started out blue and there weren't any cu's forming until around 1:30 PM. The forecast called for west winds lightening up in the middle of the day near the Florida ridge due to the on-shore flow from the east coast. There was a strong lapse rate according to the FSL sounding for Kissimmee with a high cloud base at over 6,000'. That is where the cu's started popping.

Still the cu's took a long time to get going and it wasn't until 2:30 PM that we started launching. A very late day for Florida. The winds had been then lightened up significantly and we were getting a convergence zone over the middle of the state.

I flew with just an audio vario not even thinking about how good this day would turn out to be. Mike Barber, who had a student at his World Team Academy, would register 1700 fpm on his Tangent averager.

By 4 PM there were cumulus clouds every where and doing the 40 miles box to the north and west of the Ranch was as easy as pie. What was hard was getting down at the Ranch after the flight.

Soon after I figured out that I had just missed a world record day thanks to Mike. I hadn't thought about setting triangle records in Florida, but I just missed my big chance to really set a couple of new records and raise the bar way up high.

The forecast showed a similar day on Thursday, but with less lift predicted. Now that it was too late to take advantage of the best conditions, I was ready with my Colibri data logger and a two-task flight plan. Using the Seeyou flight planning and analysis software I was quickly able to create two FAI tasks for the right length just by right clicking on the task map and adding a couple of new turnpoints. I could then download the combined tasks into the Colibri to declare the task.

The FSL sounding prediction for Thursday 2 PM for Kissimmee shows a high cloud base, west winds and a moderate lapse rate.

Thursday started off with early morning fog that quickly burned off. It was nice to see that fog as it indicated light winds. Still, later in the morning there was a good breeze from the west.

Like Wednesday we waited and waited for the cu's to start forming. Not until around 1:30 did they begin to show up in the distance. It would be a while before they appeared over head.

It was not until 2:50 that I finally decided to launch as the clouds were now forming next to the Ranch. Twenty minutes later I was at 6,000', in nice warm air (no gloves), climbing at between 400 and 500 fpm. I headed straight for the start gate at Wallaby and took it at 3:16 PM at 5,700'. I knew that I didn't want to be too high, as I needed to get back to the Ranch at 4,100' or higher.

The Thursday 4 PM satellite image shows that there are small cumulus clouds over Florida, but not cu nimbs. 

I then headed northwest to the turnpoint only about 5 miles away at the headwaters of Withlacoochee River. I got lift right on the way that got me back to 6,000'. I didn't have to turn again until half way to the second turnpoint.

It took two thermals to get high coming into the second turnpoint at Dean Still Road and Old Grade Road (a former Wallaby Open start gate). I continued toward the Ranch after rounding the second turnpoint and got down to 3,100 two miles from goal. I only had to take the thermal that was there are marked by a cu to 4,900' to make it with enough altitude to get to the goal high enough to qualify the flight. The flight takes me all of 33 minutes.

I thought that I might try to gain a little altitude before I went off on my second task, but when I went back to get the lift it wasn't there. I decided just to head toward the first turnpoint using the finish point of my last task as the start point of this second task.

I had started a bit low 4594' and wasted a bit of time going in the wrong direction and now I was flying through light lift and getting down to 2,500'. I was trying to get under a good cloud and in some stronger lift. The cu's didn't have any vertical development to them, and the lift was only moderate.

By continually pushing out in front and not bothering with the lighter stuff, I was finally able to locate some 500-fpm lift that soon turned into 700 fpm. This would be the best lift of my flight and I would get the highest on this task in this thermal, 6,800'.

There were plenty of clouds on my way to the turnpoint at the intersection of 33 and 474, 9 miles to the northwest of the Ranch. I was able to climb back up to 6,400' just before the turnpoint.

Heading south to the next turnpoint southwest of the intersection of Dean Still and highway 33, I had to run a bit to the west to get under some clouds and I was down under 2,000'. I had to work 300 to 400 fpm to get back some of my lost altitude before I could slip over to the turnpoint to my southeast and get under a better cloud with lift over 600 fpm. I climb to 6,500' and it looks like I can glide back the 9 miles to the Ranch and make it will enough altitude to be within the 2% parameter.

I run back to the Ranch at 50 mph and get there with more than enough height having hit plenty of lift on the way. I complete the 50-kilometer FAI triangle task in under an hour and 15 minutes.

I go out again for a third time to see if I can break my new 25km-triangle record. At 5:30 I climb out 4 miles northwest of the Ranch to 7,500', the highest I've been in Florida this year, and race back to the Wallaby Ranch start gate to take it at 6,000'.

I find the next thermal half way to the second turn point, but the cu's are getting pretty sparse this late in the day, and although I climb back to 6,000' I'm not able to find enough lift to get me back to 4,500' as I go to goal.

The air was completely enjoyable and if setting records were always this much fun, there would be a lot more record setting going on.

Of course, I realize that these are very minor world records, and I probably wouldn't have even thought about breaking them, but I saw that Tomas was not too ashamed to do so this last summer in Wilcannia. I would have loved to have beaten Tomas's records, but it looks like I picked the wrong day. For these short flight, it appears to me that picking the day is the main pilot skill that is tested.

Of course, like during my world record distance flight, I used my wheels and my round Icaro base tube. I could have easily switched to my carbon fiber aerodynamic base tube with the micro skids, but didn't.

Thanks to Felix Ruehle for a fine ATOS glider. Thanks to Saskia, Gianni and Peter Radman for getting it to me. Thanks to Nene Rotor and Carlos Bessa for getting me a a slick Rotor harness (is a bit too big around for me though). Thanks to Steve Pearson for the WW Slipsteam down tubes, George Ferris for the Tyvek glider covers, and Heiner Beisel for the Heads Up.

ATOS – Wills Wing down tubes »

Mon, Apr 23 2001, 4:00:01 pm EDT

ATOS|Steve Pearson|Wills Wing

With a very large helping hand from Steve Pearson at Wills Wing (well, he did all the difficult work), we were able to put on a set of Wills Wing Streamline down tubes onto my new ATOS. We used the existing ATOS Finsterwald hardware on the bottom of the downtubes and used the WW hardware on the top.

We replaced the heart bolt with one that was ¼" longer. We added a ¼" of washer on each side of the down tube top bracket to give the down tubes enough room to fold back along the keel when we packed up the glider. The front of the WW downtube bracket almost interferes with the rings that connect the trailing edge to the keel.

The down tubes didn't interfere with the flaps.

We needed to trim off the front and back of the bottom of the down tubes to give some room for the front and back wires. To hold down the plastic pieces that clamp down the wires, we had to drill holes through the plastic pieces and put clevis pins through them.

We expanded the WW down tubes to accommodate the ATOS bottom bracket, by putting the down tubes in a vice.

Wills Wing Prototype 12 is flying

Sat, Mar 24 2001, 5:00:03 pm EST

Florida|Rob Kells|Steve Pearson|Wills Wing

Got a note from Rob Kells this morning, that their new prototype is back flying again after Joe's little incident. They made up a new one at the factory while Steve Pearson was out here. Took back parts from P10.

My understanding is that P9-P12 are all about the same. There hasn't been another round incorporating any changes lately. There should be a list of things to do after the Brazilian Nationals and after Rob and Steve fly P12. Probably these changes won't be in the WW prototype gliders that fly at the Florida meets (but then Paris was already doing well), but who knows.

Wills Wing Anniversary – a blow and rain out »

Sun, Mar 18 2001, 5:00:03 pm EST

Florida|George Ferris|Mike Meier|Rob Kells|Steve Pearson|Wallaby Ranch|weather|Wills Wing|Wills Wing Anniversary

Well, we did actually have a darn good time, but previous Wills Wing Anniversary parties here at Wallaby Ranch had raised the bar pretty darn high, and this year (a drought year) the weather did not cooperate. Yes, we did get a little flying in, but we are used to (spoiled) so much more.

Personally, I really enjoyed the many opportunities I had to speak with Steve Pearson, Rob Kells and Mike Meier. They weren't as busy as they would have been otherwise (they would have had no time to eat or sleep) so I was able to get a new deployment bag (the day before Joe let go of his). We thoroughly discussed wire size, drag, the results of the wind tunnel tests of the Wills Wing down tubes, the mistakes in the recent Fly and Glide article on hang glider drag reduction, the new prototype, the new Rotor harness, which Wills Wing sells, parachute packing, rubber bands, and bridle length.

Rob was very adamant that your bridle had to be long enough to get out past your wing tip. Of course, you do have to throw the parachute hard enough to get it out there.

Rob used his new rubber bands (the kind that don't melt) to pack my chute into the deployment bag (tucking only one turn of the lines into the rubber band so that they would come out easy).

Plenty of pilots flew. George Ferris stayed up on his ATOS for a couple of hours one day (until he heard the new dinner bell, which can be heard all over the Ranch). Rob brought down 19 demo gliders, which are now going to be spread up and down the East Coast.

Linda Meier at Wills Wing sent out boxes of Wills Wing sweaters and sweatshirts. The first thought was that we needed t-shirts out here in Florida. Turned out, sweaters and sweatshirts were the ticket. Like all WW clothes, these are very nice looking. I suggest picking some up at Wallaby or from WW.

Dan Jester «dan.jester» brought down some of his machined brackets for attaching your Brauniger or Flytec vario to a 22 mil or 19 mil down tube – say like the WW downtubes. These clamps give you extra purchase on the downtube so your vario won't swing from side to side in the wind. Contact Dan. I believe these beauties go for $75/each. I'll put out a photo soon and will test them with by instrument pod.

It rained hard today and that should continue through tomorrow. Very little chance of fires causing any problems during the Florida meets now.

Bounced Czech

Fri, Mar 16 2001, 3:00:00 pm EST

Belinda Boulter|Bob Grant|Joe Bostik|Mike Meier|Richard Walbec|Rob Kells|Steve Pearson|video|Wallaby Ranch|Wills Wing

Belinda Boulter|Bob Grant|Joe Bostik|John "Ole" Olson|Mike Meier|Richard Walbec|Rob Kells|Steve Pearson|video|Wallaby Ranch|Wills Wing

(?-i)John "Ole" Olson|Belinda Boulter|Bob Grant|Joe Bostik|Mike Meier|Richard Walbec|Rob Kells|Steve Pearson|video|Wallaby Ranch|Wills Wing

Belinda Boulter|Bob Grant|cart|Joe Bostik|John "Ole" Olson|Mike Meier|Richard Walbec|Rob Kells|Steve Pearson|video|Wallaby Ranch|Wills Wing

Belinda Boulter|cart|Joe Bostik|John "Ole" Olson|Mike Meier|Richard Walbec|Rob Kells|Steve Pearson|video|Wallaby Ranch|Wills Wing

Belinda Boulter|Bob "Skydog" Grant|Bob Grant|cart|Joe Bostik|John "Ole" Olson|Mike Meier|Richard Walbec|Rob Kells|Steve Pearson|video|Wallaby Ranch|Wills Wing

Joe Bostik just about killed himself in front of over a hundred witnesses today at the Wallaby Ranch. Later, when I talked to him I mentioned how cautious and careful he had been over the last year, he said that the impulsive guy was still there and that he wasn't practicing impulse management this morning. For a few minutes there he thought he was Mitch MacAleer.

I was with Joe just before he took off in the cart flying the Wills Wing prototype number 10. Numbers 9 and 11 are in Brazil with Paris and Richard Walbec. Number ten is here so that Steve Pearson can spend next week working on it. Looks like he'll have to come up with new plans.

WW Prototype number 10. Belinda Boulter in front, Rob Kells to the side, Mark Forbes, photographer

I was laughing with Joe as he was just about to go as he was pulling himself way far forward on the cart and sticking he elbows way out to the side. He was a site. Joe likes to get far forward so that the glider sticks to the cart until he is going nice and fast.

The next time I saw Joe he was rotating quite quickly under a glider that was doing its best to resemble a maple seed with only one working wing. There was a twisted and partially inflated Laura Gold parachute entangled in the tip of the most broken wing.

My first thought was, was the parachute going to twist up even more and thereby become total ineffective. After a couple of revolutions it seemed like the parachute was finished wrapping up, and that it would not get any worse. Then, I realized that this was the Wills Wing prototype – orange, but I still hadn't realized that I was watching Joe, five feet below the twisting wrecking twirling toward the ground just behind us.

It looked the glider was actually the parachute as the wing that still resembled a wing was flying in circles and Joe was coming down pretty slowly from about 300 feet. Still he was horizontal and completely exposed. He would hit the ground first, and I sure wanted him to hit the newly disked ground to the west of the tandem launch.

He landed, we were right there. I thought someone would have actually been close enough to catch him. He was fine but we sent him to the hospital for a check up right then. There were medical personnel who attended to him immediately.

Mike Meier, Steve Pearson, and Rob Kells, all of Wills Wing, after they knew Joe was fine, began to examine the glider and Joe's harness to try to figure out what happened. There were a number of eyewitnesses who saw the actual breakup, so that helped.

Joe was doing whip stalls. He did one and then he did another. Nothing bad happened. He liked it. He was feeling very good about the glider (this was his first flight on it). He was feeling a bit too good.

Each whip stall was progressively stronger. On the third whip stall, he held the nose up for a count of 4 second according to Neal who was flying over him in a tug. Joe says that he felt that he could just get that glider's nose up and hold it there like he had seen Mitch do. He wasn't going to pull in until he felt himself tail sliding. When the wind started coming from his back, he pulled in.

The glider didn't go straight over, up one wing went down first, and Joe was now above the glider. Now no one is quite sure what happened then. Joe either lost the base tube at that point, or after one more tumble.

When he lost the base tube, he slipped down and back over the trailing edge. After a day's worth of detective work, Mike was able to determine that Joe's harness straps came over the trailing edge and started a rip there. This rip quickly spread to the Mylar sail pieces and the sail ripped in half to the nose.

The right wing with nothing to hold it back swung forward causing the right leading edge to fail in compression about four need from the nose, something that they had never seen before. As the wing continued to swing forward the thicker (3/32") side wire connected to the cross bar junction put stress on the thinner (5/64") right side rear wire. This stress broke this thinner wire at the nico at the keel.

Now this is the preliminary finding and Mike will come out with a complete report later after he thinks through everything and gets further information from witnesses. Bob Grant has a video of Joe spinning, although not of the original break up.

It is clear that this accident like almost all hang glider accidents was a case of pilot error (hubris). The glider failed in a manner that was to be expected given where Joe fell.

Joe also screwed up his parachute deployment. He reached for the parachute and got it out, but then just mildly tossed it into the air. He said it was floating out there about ten feet from him still in the deployment bag until the bad wing came around and hit it. The lines were immediately tangled up in the broken wing.

Joe was lucky that it inflated at all. He needed to get that bag out there twenty feet away from the wreckage. He needed to grab the bridle and pull on it to get the bag off, but the wing got the parachute before he could.

Finally, he had checked his deployment bag and rubber bands, but one rubber band was melted into the hole and didn't release. Joe didn't notice this problem with the rubber band. The parachute came out of the bag through a reduced orifice.

We are very happy that Joe didn't die in front of us. We are sorry that Wills Wing has a destroyed glider, but the bargain was worth it. We hope that everyone will think better about how to avoid this situation for themselves.

Wills Wing at the Wallaby Ranch

Wed, Mar 14 2001, 4:00:05 pm EST

Paris Williams|Richard Walbec|Rob Kells|Steve Pearson|video|Wallaby Ranch|Wills Wing

It's been blowing hard here today and two days ago. Yesterday it was mostly overcast with some rain. It is supposed to blow hard tomorrow. Maybe the weekend will be better.

Rob Kells has prototype number 10 of their new wing here. Steve Pearson is also here and I've seen them put in different sets of battens in this prototype. Rob has pasted cassette tape to the top surface and taken videos of the airflow.

Paris Williams has taken prototypes numbers 9 and 11 to Brazil to fly with Richard Walbec. Richard will get 11. The Brazilian meet in Governador Valadaresbegins this weekend. We'll bring you the results.

The new prototypes have much reduced flap (increased reflex) relative to earlier prototypes. There is a trade off between the rate of climb and your glide ratio at high speeds when you do this trade off.

Air Blade

Sat, Feb 17 2001, 6:00:03 pm GMT

ATOS|Steve Pearson|Valerio Canestrelli

Valerio Canestrelli «vacanes» writes:

I'm Valerio Canestrelli from Italy, an Atos pilot with about 20 years of model building (i.e. composite frames) experience, and 15 of hang gliding. I hand built the "AIR BLADE" from a wood model, the fiberglass mould to the finished basetube. It was a very hard work to make the first one in June 2000. I made it for my friend Gaetano Matrella. But, I was widely rewarded when he won the Austrian 2000 European Championships, Class 2, with his ATOS (that now is mine!!).

Now I have finished one for me. As you can see, there are some "clever" ideas like the clam cleat for the flap rope faired inside the skid, just like the "aerospeed" basetube. The bar itself can rotate on fittings (due the oval holes) for the right angle of attack. Also this helps during setup and with hard landings to stop damage to the bar connection (this is possible as the skids act as levers).

I can only work to my creatures in the spare time during the week (weekends are for flying). Besides, at my flying site there are a lots of rigid wings (7 ATOS, 1 GHOST, 3 XTC, 1 E7, 1 SWIFT!!) so there is a plenty of repair work for me on carbon frames like ribs and D tubes.

As it took 80 hours to build the first one, I think only moral satisfactions can pay for these (like Gaetano Matrella gave me by winning the Austrian meet!). Gaetano gave me 800000 lit. (about $400)

For the next version of "AIR BLADE" I've asked to Steve Pearson if he can send me the airfoil section of W.W. carbon downtubes, and he said yes.

Discuss "Air Blade" at the Oz Report forum   link»

Less down tube drag

Wed, Feb 14 2001, 8:00:00 pm EST

carbon fiber|Steve Pearson|Wills Wing

A while back (https://OzReport.com/Ozv4n196.htm) I wrote about the new Wills Wing aluminum down tubes. Steve Pearson at Wills Wing wrote:

It's not possible to quantify the results with a single number because the drag is very sensitive to angle of attack and Reynolds number. Very generally speaking, the results verify a drag reduction of 80-90% (Slipstream is 10-20% of the drag) of a standard Finstwalder section. It also has a very wide low drag bucket.

I also gave readers the address of the paper that described the wind tunnel test results at http://www.willswing.com/articles/SlipstreamWT.asp. Finally, I was able to stop long enough to have a good Internet connection and I down loaded the paper. After going through it I had a few questions for Steve and wanted to get a clarification of what the test results meant.

How good was this new aluminum down tube? Was it really that much better? How about compared to the carbon fiber downtube? Here is what I asked Steve:

A couple of questions on your wind tunnel tests.

What is Ca?

Steve answers:

lift coefficient - cl

What is Cw?

Steve answers:

drag coefficient - cd

What is Alfa?

Steve answers:

angle of attack - aoa

On which charts can I find the coefficient of drag (Cd) from the Finesterwalder, WW standard, and new WW aluminum tube?

Steve answers:

The wakes from the Finsterwalder, WW standard, and the round tubes were too big for the tunnel and the pressure rake. The drag was estimated from the lift vs. drag curves* (and other observations) and is tabulated separately on each page.

* If you look at the 2 graphs of the '1.1 WW standard carbon tubes' (cl vs. cd, and cl vs. aoa) you can see that there is a correlation between rapid increases in the drag coefficient and a drop or erratic change in lift coefficient.

How do I tell if the new tube drag is 80 to 90% reduced from the old tube?

Steve answers:

80-90% is the best case comparison. 15m/s is ~33mph. Looking at the 'WW Standard Carbon' 15m/s curve, Cw stays at or below .04 over a wide angle of attack range ~ +/- 8 deg. The estimated drag coefficient for the Finsterwalder tubing is .28 - .35. .04/.28 = 14.3% ; .04/.35 = 11.4%. The performance advantage diminished until at 30m/s we have .033 for the carbon vs. .11 - .2 for the Finsterwalder = a 70% to 85% drag savings.

None of the best comp pilots are flying with fat Finsterwalder type sections, so the Seedwing section is a better comparison.

At 10 m/s, the Seedwings section has too big a wake for the tunnel instruments (>.08). the advantage for the WW Carbon is ~ .04/.1= 40% (60% less drag). You can also see that from the Ca vs. aoa curve. At 10 m/s the separation starts right away but by 15 m/s the Seedwings section is pretty good.

The inverted bucket shape of the cd vs. cl curve is a result of the squared of trailing edge shape. The average cd is ~ 0.7. The WW carbon is < 0.4 for the entire aoa range, so the carbon has 40% less drag.

Another interesting result is '1.4 WW carbon, no Trip'. For this test, I asked Carsten to sand off the turbulator trip. Comparing tripped and untripped carbon sections, at 10m/s the untripped section has so much drag that it doesn't even show up on the graph (Cw >.08 == more than twice the drag of the tripped section).

At 30m/s, the untripped section has less drag than the tripped section. I was interested in this test because of the unconfirmed reports that the Freeman speedbar had high coefficients.

The aluminum profile as extruded measures ~ 21.0 mm. I designed the extrusion to use a slide-in web (.028 alum sheet) that can expand the width as required for structural requirements. As you noted, the strength of the downtube is very sensitive to the finished width. The finished WW downtubes are 22.0 mm. The slight dip in the rear of the alum section is an artifact of the extrusion process. Fortunately, it seems to have reduced the drag coefficient so I'm leaving it as is.

I really need to prepare a summary of the results. I understand that it's pretty hard to interpret the results. What everyone really wants to know is 'how much better will I glide'.

Airfoil downtubes and speedbars that aren't canted the proper amount are probably completely separated. Separated airfoil sections aren't much better than round tubes. Compared to that, the difference could be 2 points or more.

Compared to a standard WW type control bar, the difference is probably more than 1 point. Compared to a good section like the Seedwings profile mated to a good streamline basetube, with all the tubes oriented properly, the difference is probably 1/2 a point. Those are just educated guesses based more on flight reports than calculations. I always take observation over calculation anyway.

I commissioned the tests because I wanted some confirmation that the finished product met the performance predicted by the airfoil design programs. Also, I wanted to know the drag behavior at higher angles of attack where the programs become less reliable. Since the in-flight angle of attach range of both the basetube and downtube sections is 20 degrees or more, it's just as important to have a wide drag bucket as a low minimum drag coefficient.

(editor's note: My competition pilots and other readers are encouraged to look over the test results and think about the "proper" canting for their speedbar and downtubes. There seem to be some very significant differences here between doing it wrong, and getting everything right.)

Flytec pod »

Fri, Jan 12 2001, 10:00:04 am EST

Paris Williams|Richard Walbec|Rob Kells|Steve Kroop|Steve Pearson|Wills Wing

I wrote a brief article yesterday that was mildly critical of the new Flytec instrument pod. Steve Kroop«USAFlytec»,who never gets his feathers ruffled by criticism (and therefore helps his case immensely) writes back to help clarify some of the points I raised:

The pods that Paris, Bo and Revo have are prototypes. Vern (a friend of Revo's) who is manufacturing these is already working on, what should be the production model, available in about two weeks. This version is thinner and narrower. The pod will, however, be a bit wider than the others because all of the cables and connectors (GPS interface and airspeed probe) are enclosed within the pod. The goal here is to clean up the airflow, protect the connectors and prevent inadvertent cable disconnect.

As far as the bracketing is concerned the pods will be available with a fitting that will allow the bracket to be bolted to a control frame. For those pilots who do not care for this approach the standard Flytec bracket is available with extra wide Velcro straps (1-1/2" wide as opposed to 1"). Any remaining rotation can be eliminated with a 3/4" x 4" piece of friction tape on the control frame at the bracket attachment location.

Wills Wing prototype

I'm getting a lot of interest in more information about this new wing. I spoke a bit with Paris Williams who is the US pilot flying it here. He said that he worked hard to convince Rob Kells and Steve Pearson that it was a good idea to use competition in the glider development process, and this is something that Wills Wing hasn't done before, or at least not recently.

The prototype is in the very early stages of design and development. It is something that Wills was able to throw together very quickly. According to Paris, it turns out that they got a lot more things right than should have been the case given its how early in the design development it is. The choice of airfoil turned out to be much better than they expected.

Paris states that in thermals the glider is the most neutral handling high performance glider that he has flown. He and Richard Walbec already have a long list of small improvements that they want to see made to this prototype.

Those cool new Wills Wing downtubes

Thu, Nov 2 2000, 12:00:01 pm EST

Steve Pearson|Wills Wing

Steve Pearson «Steve» knew I couldn't wait, but then he is right on the case with the URL for their new downtubes:

Here's the link: http://www.willswing.com/articles/SlipstreamWT.asp

New Wills Wing downtubes

Tue, Oct 31 2000, 2:00:00 pm EST

CIVL|Steve Pearson|Wills Wing

I sent the following message to Steve Pearson at Wills Wing a few days ago.

"First, you've produced new aluminum down tubes. You mentioned that you were working on these when you were at the Ranch. They are thick enough to pass the previous CIVL restriction (thicker than 22 mm). I wonder, will they pass the new CIVL restriction for DHV certified? Just a joke, Steve.

I heard that you had them tested at the Stuttgart wind tunnel. If true, can I get the results/documentation?

I heard that they had 9 times less drag than your old down tubes? True?

I heard that you are going to sell them to other manufacturers. True?"

Here's what Steve@willswing.com «Steve» had to say:

We're about to post a complete FAQ and the wind tunnel report on our web site. The report compares several variations of turbulators on the carbon tube, the new 22mm aluminum tube (we're calling it 'Slipstream') and also standard WW and Finsterwalder streamline sections, and the Seedwings section.

It's not possible to quantify the results with a single number because the drag is very sensitive to angle of attack and Reynolds number. _Very generally speaking_, the results verify a drag reduction of 80-90% (Slipstream is 10-20% of the drag) of a standard Finstwalder section. It also has a very wide low drag bucket.

If you can wait a day or two to post this info, I'll forward the url to the report for your readers. The FAQ will also cover pricing and availability, certification issues, structural data, etc. We will be promoting them for OEM and aftermarket sale to comp pilots. The price will be much lower than the carbon tubes.

The mill run is in process and I only have 4 sample tubes right now.

(editor's note: The very very conscientious reader will recall my story on the aluminum airfoil base tubehttps://OzReport.com/Ozv4n95.htmthat bares a striking resemblance to this story.)

Wills Wings' Carbon Fiber Control Frame

Sun, Sep 17 2000, 1:00:03 pm EDT

carbon fiber|CIVL|Rob Kells|Steve Pearson|Wills Wing

Rob Kells, «Rob» writes:

It is our understanding that the CIVL minimum safety standards apply to category one meets only. That gives us until the next world meet to sort this out.

There seem to be three key issues with regard to the carbon control frame. Cost, structural strength and crash-worthiness.

High cost is always something to avoid when possible. However we are not banning 9000-dollar rigid wings in CIVL comps, nor 1000 dollar Varios, or 1200 dollar harnesses. The price of our carbon frame including fittings and cables is 1000 dollars retail. Experienced comp pilots like you Gordon can get one for about 750.

The strength of this bar doesn't seem to be a problem. Steve Pearson designed it to be good for a minimum of 1500 pounds, or over seven Gs for most pilots. We have load tested it on our vehicle, submitted it to the HGMA and received certification for it. There has never been an in flight failure with this control bar.

An improperly designed carbon part could present nasty sharp shards of carbon in a crash. Our bar has a woven sock on the outside so the broken end of the carbon section is no worse than that of a faired aluminum section. In fact our carbon downtube breaks easier in a crash than our aluminum section.

A number of pilots have broken this control bar on bad landings with no injuries. Many pilots fly with carbon helmets, carbon base tubes, and some with carbon harnesses. The 22mm control frame rule was written to eliminate the use of carbon fiber downtubes. Cost, structural strength and crash-worthiness as sighted above were the reasons given. To have a few outspoken individuals in the CIVL dictate the future of hang glider design is ridiculous.

Short takes »

Wed, Mar 29 2000, 2:00:06 pm EST

David Glover|Ghostbuster|Heiner Biesel|Mark "Gibbo" Gibson|Mark Gibson|Steve Pearson|USHGA|Wills Wing

Will's Wing Designer Steve Pearson (http://www.willswing.com) has made a 300+ square. foot, 50lb glider for training and is offering the design royalty free to all hg companies, and to schools at cost, slow speed, easy to fly, orders flowing in, good for the sport.

Steve Pearson of Wills Wing

Mark Gibson (http://www.gibbogear.com) is planning on building a very low cost, very easy to fly hang glider for getting new people into the sport.

I flew with Heiner Biesel's constant force pulley. I pulled it a bit too tight, so that was more force on it than I really needed. Still it was great. No weight on my shoulders! One funny consequence is that the forces that you normally feel on your head are no longer there, so you have to get used to it as the force vector moves.

Steve Pearson states that the regular Wills Wing aluminum down tubes have 25% less drag than the similar (but not quite the same) Finsterwald downtubes (like those used on the ATOS, Ghostbuster, etc.).

Got a few replacement sets of push to talk connections from Mike Dillon at http://www.flightconn.com a few days ago. These are the newer PTT 2 sets. Check out his web site if you are looking for PTT's. Great service, and a desire to get it right.

The USHGA web site (http://www.ushga.org) is being continually updated. They've spent about $6,000 with the professional web-development company so far, and the budget is for $10,000. If you have any input on improvements, please send them to «ushga» or David Glover, «dhglover». Soon you'll be able to renew your membership on line. If you've signed a waiver once, you don't have to sign again.

Staff photographer: David Glover

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Spins naturally?

Wed, Mar 29 2000, 2:00:03 pm EST

Ghostbuster|Mike Barber|Rob Kells|sailplane|Steve Pearson|Terry Reynolds|Wills Wing

I was going to go up with Terry Reynolds today and do a few spins in his sailplane. Mike Barber was up first and they got started late and had so much fun, that I missed my chance. Mike really liked Terry's sailplane. I've been saying that it is a good one. Flies like a hang glider.

Terry Reynolds

I continue to have it confirmed that there is a sharp dividing line. On one side are the sailplane and ultralight sailplane pilots that consider spins as a natural part of aviation. Then there is the other side, the hang glider side, that considers spins as aerobatics, something that is difficult to get a hang glider to do, and that a hang glider recovers from automatically if you just stop trying to keep it in a spin.

For the most part those rigid wing gliders that have been successful commercially have been built by companies that recognize that they have to sell to the hang glider market. The perception of the buyers in that market is that the rigid wing won't easily spin.

We know that it is quite difficult to spin the Exxtacy and the ATOS. It appears that this is true except in unusual configurations for the Ghostbuster (and I just happened to walk into them a couple of times out of four).

I spoke at length with Steve Pearson about the control-frame Millennium project. He said that when they first started, they just put the control-frame on the Millennium, and they thought the glider was just fine. Then Rob Kells took it up, put it into a stalled turn, and "it spun like a top."

They have redesigned the CF Millennium so it behaves a lot more like a hang glider, spin resistant. Now the only issue for Wills Wing re producing this thing for market, is whether there is a market for it.

It was clear from this conversation, once again, that there is the hang glider reality and then there is the sailplaner or ultralight sailplane reality. Manufacturers have made our hang gliders very spin resistant. Some people thing that this is no fun. I don't count myself among them.

This doesn't mean that one group of pilots is right and the other is wrong. It just means that there are very good reasons for the differing perceptions.

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Laminars with Wills Wing control frames

Wed, Mar 29 2000, 2:00:02 pm EST

carbon fiber|control frame|Ghostbuster|Laminar ST|Manfred Ruhmer|Mark "Gibbo" Gibson|Rich Burton|Robin Hamilton|Steve Pearson|Wills Wing

Steve Pearson fitted Rich Burton, «indasky», with a Wills Wing carbon fiber control frame on his Laminar ST. He redid the wires so it worked out. Looks like he might be doing the same for Robin Hamilton. He said that if Manfred wanted a set, he should contact him.

Flight Design has a control frame, and it looks like Gibbo will be getting one directly from Wills Wing for his Ghostbuster. I've been holding this news, until it was too late for anyone else to get one in time for the Florida meets for their Ghostbuster.

The control frames aren't quite right for the Ghostbuster as they have a different rake to their down tubes. Steve has made some adjustments so they fit well enough.

Everyone who sees the wonderful design of this control frame wants one ($1000/control frame). Wills Wing had no idea that they would be making this into a product. It takes a four-axis NC mill to mill the aluminum fittings seen above.

Wills Wing can justify further development work and time on the NC machines, if lots of different companies and individuals are interested.

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USHGA responds to unfounded rumor

Wed, Mar 15 2000, 3:00:01 pm EST

CIVL|Dennis Pagen|John Borton|Rob Kells|Steve Pearson|USHGA|Wills Wing

CIVL|Dennis Pagen|John "Ole" Olson|John Borton|Rob Kells|Steve Pearson|USHGA|Wills Wing

(?-i)John "Ole" Olson|CIVL|Dennis Pagen|John Borton|Rob Kells|Steve Pearson|USHGA|Wills Wing

CIVL|Dennis Pagen|John "Ole" Olson|John Borton|Rob Kells|Steve Pearson|USHGA|Wills Wing

Got a very timely response from John Borton, head of the USHGA competition committee. Looks like the new USHGA is in command.

Yesterday I reported that I had heard a rumor about the CIVL Bureau over ruling CIVL re the 22-millimeter minimum thickness of the down tubes. I also reported that GW stated that he had been told that Wills Wing was appealing (whatever that means) the 22 millimeter rule.

John Borton says, «CompCommittee», writes:

Dennis Pagen, the US CIVL delegate, tells me that there have been no CIVL Bureau meetings since Spain and thus no reversals regarding any of the decisions made at those meetings.

Apparently, upon his return to the states, Wills Wing came to him with what he considers new information regarding the exclusion of their carbon control frame. He became convinced that this information, favorable to the WW control frame, was not presented at the Spain meetings and should have been considered in the decision process. He informed WW that they could package this new information along with his comments in support of a reversal and appeal to the CIVL Bureau for review. You, of course, have now heard Rob Kells from Wills Wing say that they have yet to take any action on Dennis's recommendation.

Rob Kells, «Rob», writes:

As far as the CIVL safety standards, we are very disappointed in their decision to enforce a 22mm minimum width standard on control frame downtubes starting in September 2000. This will "outlaw" our carbon bar in CIVL competition.

We have not taken any action in response to this. Steve Pearson engineered the bar to meet HGMA certification standards, and we have tested it and documented that it does meet these standards. We will be proceeding with formal certification of the bar as an option on the Fusion. The bar is available for purchase on an OEM basis to other manufacturers, and many have expressed an interest. The feedback we have so far from other manufacturers indicates that they also do not support the CIVL's decision on this rule. We'll see what happens.

So there hasn't been a CIVL Bureau meeting to over turn the new Class I competition rules including the 22-millimeter rule. But, it does appear as though it has been contemplated that this rule at least get reviewed and perhaps over turned at the next CIVL Bureau meeting.

The CIVL Bureau meets to make interim decisions because it is impractical to have the whole of CIVL meet more than once a year. But that was before the Internet. Perhaps it is time that some CIVL business take place on-line. Certainly a review of new information about the 22-millimeter minimum thickness is a good candidate for an e-mail or list interaction among CIVL delegates.

Wills Wing could present its information to the general CIVL body re a listing on the CIVL discussion board. Other CIVL delegates could add their input. There could then be a vote.

This would be a much more open process. The Bureau wouldn't have to contemplate overturning a measure that was passed nearly unanimously, and a decision could be made much quicker.

I hope that CIVL is open to trying this bit of new thinking about organizations and how to make decisions. This seems like a perfect test case.

Wills Wing faired control frames

Sat, Jul 24 1999, 6:00:02 pm EDT

carbon fiber|Rob Kells|Steve Pearson|Wills Wing

Rob Kells writes that Wills Wing will make the Steve Pearson created carbon fiber control frames that I reported on in the last Oz Report available on the Fusion.  He says that they need to figure out a price first, and that they won't be cheap.  Here's a better shot of the control frame:

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