Oz Report
Volume 6, Number 406 pm, Monday, March 4 2002
https://OzReport.com
"Toto, I have a feeling we're not in Kansas anymore."
- In this issue:
Trainer wheels Comparing the LightHawk and the SparrowHawk Break those Carbon Dragons Flare PTT units 2002 Canadian Nationals Aerial Adventures – more adventures
Trainer wheels
Mon, Mar 4 2002, 4:00:00 pm GMT
Barry Bateman|William Jonathan "Jon" Orders
Barry Bateman «flyxc» writes:
Aussie, Jon Orders who has been competing at the Oz comps and who presently resides here in Vancouver, BC has just sent me these pictures of Aussies in training in Western OZ. Maybe you can use them to enlighten your readers on "Alternate" training methods.
(editor’s note: Notice the wires holding the glider.)
2 topics in this article: Barry Bateman, William Jonathan "Jon" Orders
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Comparing the LightHawk and the SparrowHawk
Carbon Dragon|CIVL|Greg Cole|sailplane
Carbon Dragon|CIVL|Greg Cole|John "Ole" Olson|sailplane
(?-i)John "Ole" Olson|Carbon Dragon|CIVL|Greg Cole|sailplane
Bob Mackey|Carbon Dragon|CIVL|Greg Cole|John "Ole" Olson|sailplane
Bob Mackey|Carbon Dragon|CIVL|Greg Cole|John "Ole" Olson|sailplane
Why would hang glider pilots be interested in these ultralight sailplanes (or light sailplanes in general)? Because they are the closest thing to hang gliders while still providing vastly superior performance. They are light enough to fly in light conditions and still stay up. We’ll see over the next few years just how they develop and how popular they can become.
LightHawk (http://www.pure-flight.com/) :
|
Metric |
English |
Wingspan |
15 m |
49.2 ft |
Wing Area |
|
126 sqft |
Empty Weight |
68 kg |
150 lbs |
Pilot Weight |
45 108 kg |
100 240 lbs |
Wing loading |
10-15 Kg/m^2 |
2-3.1 lbs/sqft |
max glide est. |
35:1 |
35:1 |
Max glide speed |
63 k/h |
39 mph |
min sink |
0.36 m/s |
70 fpm |
min sink air speed |
48 k/h |
30 mph |
Sink rate at 375 lbs |
.46 m/s |
90 fpm |
Circling diameter |
30 meters |
100 feet |
Stall speed (150 lbs/pilot) |
35 k/h |
22 mph |
Stall speed (225 lbs/pilot) |
39 k/h |
24 mph |
Maneuver speed |
80 k/h |
60 mph |
L/D at Maneuver |
26.4 |
26.4 |
Red Line speed |
161 k/h |
100 mph |
The LightHawk is designed to be a very light 15-meter sailplane. It is not a scaled down version of a 15-meter sailplane, but a light version of one. The claimed minimum sink rate is only 70 fpm (it looks like this is for a 100 pound pilot), about one half on the minimum sink rate that I measure on my ATOS (not ATOS-C) and I weigh in at 225 with all my equipment. It has a claimed maximum glide ratio of about twice that of an ATOS-C.
The LightHawk is designed to stay up in light conditions and to have a turn radius about that of the Carbon Dragon.
The wing of the LightHawk has three flaperons which account for about 25% of the wing area. While I don’t recall exactly how they work, as I recall inner one operates in a manner to allow one to thermal in a very tight radius.
Bob MacKey writes:
The LightHawk is an ultralight sailplane that is optimized for low speed soaring flight. Composite construction is used to provide the necessary strength to meet JAR-22 engineering standards, while weighing only 150 lbs.
The low wing loading and excellent maneuverability will allow pilots to climb in weaker lift than ever before. LightHawk pilots can expect to out climb any other gliding aircraft in the sky, and to get extended flights on even very weak days.
SparrowHawk (http://www.windward-performance.com/):
Wing Span |
36.1 FT (11 m) |
Wing Area |
70.0 FT^2 |
Length |
20.6 FT |
Horizontal Span |
6.7 FT |
Vertical Span |
4.5 FT |
Aspect Ratio |
18.6 |
Wing Loading |
5-6 LBS/FT^2 |
Load Factors:
Maneuver limit load factors +5.48g/-4.0g
Critical Speeds:
Maneuvering and Rough Air Speed Limit of 92 mph
Redline at 142 mph
At 350 LBS the minimum sink rate is 123 FPM and the stall speed is 37 mph
Max L/D of 32 is occurs at 52 mph. L/D is 22 at 86 mph.
The SparrowHawk is a scaled down version of a 15-meter sailplane. (Called 13 meters, it appears to be 11 meters.) It has twice the wing loading of the LightHawk and consequently about a 30% higher minimum sink rate (with a 200 to 225 pound pilot). It also has a 50% higher maneuver air speed limit (92 vs. 60 mph). It will fly at a much higher speed between thermals than the LightHawk.
The stall speed is 32 mph with a 200 pound pilot while that of the LightHawk is 24 mph at 225 pound. The Max L/D speed is 52 mph for an L/D of 32:1 while the LightHawk gets Max L/D at a much slower 39 mph at 35:1. I would expect the SparrowHawk to fly between thermal at about 80-85 mph at an L/D above 22:1 and the LightHawk to fly at 50-55 mph at an L/D above 27:1.
Greg Cole writes:
Although the SparrowHawk will be a legal ultralight, it is built to be flown in all the same conditions as existing sailplanes. It will cruise between thermals at speeds much greater than existing light sailplanes with more altitude retention. It will climb exceptionally well with its low sink rate and tight turning radius afforded by its low stall speed and small size
You don’t to have a glider private pilot’s license to fly these sailplanes. They won’t be certified by the FAA.
The SparrowHawk is flying. The LightHawk has a little ways to go.
If you had a chance to look at the proposed FAI/CIVL ultralight specifications in yesterday’s Oz Report (and you are willing to do a few unit conversions), you’ll notice that the LightHawk comes close to the proposed specifications for the Ultralight (or Microlight) class at a wing loading of 10-15 Kg/m^2 (13.6 with 90 kg pilot). The SparrowHawk comes in at 24 to 29 Kg/m^2 (25 with 90 kg pilot) which would put it in the light sailplane class but with ultralight weight.
13.6 Kg/m^2 is near the upper light of the proposed Ultralight sailplane class. Danny Howell (who heads up the LightHawk production team) is asking for up to 18 Kg/m^2.
4 topics in this article: Carbon Dragon, CIVL, Greg Cole, sailplane
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Break those Carbon Dragons
Carbon Dragon|Florida|Gary Osoba|George Ferris|Wallaby Ranch
The other day here at Wallaby Ranch Steve Arndt broke his Carbon Dragon when he didn’t put in the bottom bolts that connected the wing to the fuselage. George Ferris and I were engaged in quite a discussion with him at the time that he was putting the wings on and just as he was about to put the bottom bolts in we talked about how many bolts were needed.
Steve is a very meticulous guy and was obviously very embarrassed that he could make such a mistake. He rolled down the grass field behind the tug and when he got some speed, the wing lifted off, ripping out some bulkhead materials, and rotated over the top of the fuselage. Steve thankfully never got off the ground.
Two Carbon Dragons built and two damaged. I’ve been “involved” in both of incidents that damaged both Carbon Dragons.
Steve hopes to get it repaired soon. Gary Osoba has a standing invite to come down and fly it in Floridaand he’d like to come down each month for the Flytec Championship.
Steve is working on a new fuselage that will allow him to include two quarter scale RC motors that will provide ten horse power each. Enough to launch.
5 topics in this article: Carbon Dragon, Florida, Gary Osoba, George Ferris, Wallaby Ranch
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Flare
Bart Doets|Christoph Gmelin|video
Bart Doets «bart.doets» writes:
I think getting Günther Rochelt's Flair 2 into the story of the lower surface stall is incorrect. The Flair 2 had flaps that were very large, 50% of the cord. This was because Rochelt wanted the wing to fold in half along this hinge for transport; a smart idea but it had its consequences. Also, the pitch control on the Flair 2 was not by weight shift but by rudder.
The final accident happened, as I read in Drachenflieger Magazine (now Fly & Glide) when the pilot pulled full flaps and dove steeply towards the LZ. The combination of flaps and rudders all down would demand quite a lot from the pitch-up characteristics of any flying wing.
If I remember correctly, he put the stick forward first and then added full flaps. That would be a very strong pitch down moment.
The remains of that glider must still be around. What a pity the concept was abandoned - a pilot with a more conservative approach might still kick butts with it. It was flown with the pilot laying on top of the wing - just imagine the drag reduction. Not even a cage needed!
Christoph Gmelin «gmelin» writes:
I found the correct name on the rigid-wing web site http://216.234.174.84/RigidWings/flair30.htm.
The characteristic of a central flap depends on the geometry of the wing and flap AND of the C.G. of the glider. One can state two main effects of a positive set flap:
1. additional negative (pitch down) moment.
2. additional lift, pulling either in front of the CG or behind.
The construction of the Flair was thought to balance these two effects. The clever design provided the additional lift to attach a little bit in front of the CG compensating the nose-down moment of the flap. Therefore no trim corrections had to be made for almost every position of the (huge) flap.
Unfortunately the pilot who flew the glider the last time was a bit too heavy shifting the CG forward, in front of that (virtual) point where the additional lift attached. In normal flight the larger pitch down moment due to the new location of CG was compensated by a little bit elevator trim (little upwards deflection of the rudder).
When the glider came in for landing full flap was set and the glider pitched down because additional lift and moment acted in the same direction! The pilot pulled (deflected the rudder upward). In that moment, I think that the outer part of the wing stalled (on its lower side) and could not provide enough negative lift to keep the glider in equilibrium and to compensate the momentum due to the flap any more.
I saw a video of that crash and could observe the fully deflected rudders on the outside of the wing just before impact. Setting the flap to zero probably would have been the better reaction but there was not enough time.
I think it was very progressive design and it's a pity that nobody (to my knowledge) has continued this work.
3 topics in this article: Bart Doets, Christoph Gmelin, video
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PTT units
John Reynoldson
John Reynoldson «aerial» writes:
I do supply PTT units, including kits and instructions for building your own. My web page has a section with circuit diagrams for a lot of the common radios used in Oz. see: http://www.aerialpursuits.com and go to the Communications section. I've attached a quick picture of the business end of our finger switch. It's a 12mm tactile switch with a slightly raised button (for feel) mounted securely on a "band-aid" of hook Velcro.
1 topic in this article: John Reynoldson
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2002 Canadian Nationals
1 topic in this article: Canadian Nationals 2002
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Aerial Adventures – more adventures
Aerial Adventures|Mark Tulloch|weather
Mark Tulloch «hgliding» writes:
Our season atFortLangley is also about to start. Over the next two weeks we will be installing a 912S engine on the tug in place of the 914, which suffered a seizure from oil starvation during a flight last September. With luck, and the weather cooperating, we hope to be open for towing by mid-March!
For March through May we will be open Thursday through Sunday each week and from June through September we will be open Tuesday through Sunday. We will also stay open all holiday Mondays.
In October we will return to the Thursday through Sunday schedule and in November fly on nice weekends only. Towing operations will close in late November.
This year, in addition to our regular tow tickets, we are going to offer a season’s pass for pilots! The pass will be valid for the entire 2002 flying season! The cost will be $500 and allow the pilot unlimited tows to 2500 feet. All seasons passes purchased before March 31 will not be charged sales tax. All holders of seasons passes purchased before April 15 will also be entered into a draw for a new Charlie helmet!
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3 topics in this article: Aerial Adventures, Mark Tulloch, weather
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