gimballock

BREAKING NEWS! I made contact with David Rowe! I had a good chat with him and he was most obliging with information. He said that, as you know, efficiency of a wing drops off with aspect ratio, but then, at a certain point, it sharply rises again! He says that when the aspect ratio hits approximately 1.25, it is almost the same as an aspect ratio of 6. The aspect ratio of a complete circle is approximately 1.27, and so, with some added aerofoil at the rear, it is approximately 1.25. It doesn't actually stall, so much as it mushes. He didn't recall the actual point at which this happens knotswise. Power-out, it glides slightly better than a Drifter. It is very stable and flies quite well. It lands quite short. (He often lands it in the driveway of many farms out where he lives.) It's a standard aerofoil with a reflex (as all flying wings/tailless aircraft are.) The model glider he built had a Centre of Pressure at about 33% but on the full-scale model that proved unstable, so it was best placed at about 25%. As mentioned here before, the high undercarriage was due to the rotation angle and the need to avoid scraping your tail on the ground. Also, he said that the seating arrangement was purely due to the fact that he sits, basically, on top of the wing. He said that it's actually quite uncomfortable, so flights of more than an hour are not advised in this current model. I told him of the interest in low-aspect ratio aircraft on both here and homebuiltairplanes.com. I urged him to get onto this site as his knowledge would be invaluable - a person with first-hand experience is worth a thousand "internet armchair experts." Sadly, he doesn't frequent the internet very much, so isn't interested in getting on this site. He did, however, invite me to keep in contact and said that I am welcome to call any time I have questions.

Like the line from "Back to the Future" when he steps out if the De Lorian in the barn in the Radiation Suit & takes off the helmet.... "Look! He's already mutated into human form! Shoot it!" "Take this, you mutated son-of-a-bitch!" *BOOM*

Yes, I've read most of what you've said, David and I have no doubt that it's all 100% true. It's sad that a genius like Scotty has not been recognised as the genius he was. However, I'm interested in the circular form of flying wing and curious to know if their lack of success is purely aesthetic or is there a serious technical issue that precludes them from regular use. (Just like the VHS vs Beta video cassette, VHS won but all accounts are that Beta was actually better! Maybe we should all be flying around in pancake-shaped aircraft!)

Yes, well Jim Marske is another tailless design fanatic (http://www.marskeaircraft.com) but I've heard that his designs require precise CofG calibration (i.e adjusting the seat before each flight) but they are, for the most part, "flying planks" with only a small degree of sweep in the leading edge. I've read somewhere that Scott Winton's Facet Opal was, at times, quite tricky to fly but this in no way contributed to the crash that took his life.

Yes, Maj. David Rowe and Scotty Winton (May he rest in peace) are/were an inspiration to Australian Aviation. We need more.

I'm sure that I'm teaching you guys to suck eggs when I tell you that tailless aircraft can be made more stable by a swept leading edge (like a delta), an anhedral form or by lowering the centre of mass (like a hang glider/trike.) All accounts from those who have spoken to David Rowe are that it flies well and is quite stable. I'm guessing that his high seating position is simply so he can see over the nose! I haven't been successful in getting hold of David Rowe. I've left a message.

Thanks, Rotax. That's an answer that I was sort of looking for. I agree. It would make for a good sports aircraft and a good experimental platform for different engine types. For example, has anyone considered multiple small-sized electric motors along the leading edge? (Say, 2 per side at no mor than 10 or 15hp each ?) Battery life issues aside, could this lead to any significant increase in performance? (Possible near-vertical take-off/landing?) Just spit-balling. Gimballock.

I've done some digging and might have a contact number for him. I'll give him a call & if he's happy to oblige, ask him a few questions. For all those interested, stay tuned.

You're certainly right about the Camera work, Deskpilot! He got the roll and rotation but *just* happened to (irritatingly) shove the camera in the opposite direction during the climb out! But as for the design, I read that the long legs are necessary to make use of a certain aerodynamic effect. Does anyone know anything about this? Re: Rotax618's comments about "instability at all angles of attack", I am curious to know how he gets around this short of amazing airmanship, fortitude & skill! I figured that someone in here might know him as he is clearly an Aussie and this aircraft is registered with RAA. Is there another section in here where I may be able to track him down? (I'm in SEQ.) Gimballock.

Yeah, I've seen this and its 1-line "discussion" on the aircraft. Not a lot to go on, sadly. Anyone else know more? Thanks.

Hi all, Has anyone here had any experience with round/circular/disc-shaped wings? I know that they aren't popular and there were many experimental designs towards the end of WWII like the Vought V-173 (http://en.wikipedia.org/wiki/Flying_Pancake) and the Sacks AS-6 (http://en.wikipedia.org/wiki/Sack_AS-6) I've heard that this design is very unstable, but David Rowe in NSW has built an experimental version known as the "Useless Flying Object" (UFO) and there's a YouTube clip showing it flying quite happily: Surely such a design has advantages such as low-drag and low stall speed etc? Does anyone know any more on this? Does anyone know David Rowe personally? Cheers, Gimballock

Is there any software out there that would allow you to simulate such a thing? I mean, I'm reasonably competent with maths and physics, but at this stage I'm..... well... like a dog in a forest not knowing which tree to pee on! You've given some good advice, but I don't know where to start to apply it all. Maybe an aircraft design package exists to allow me to come up with some on-paper numbers? Thanks, Gimballock.

I'm picturing an aircraft that might be described as the lovechild of a Glasaflugel H101 Salto sailplane and a Monnett Moni with gradual joins of wing roots and v-tail. Obviously with shorter wings/tail to be more power plane than glider (approximately the rough dimensions of a Corby Starlet/ Taylor Monoplane etc.) Yes, it would obviously have to be of glass/carbon fibre construction. As I've said before, I don't have the means or skills to design/build my own aircraft but I'd be interested in the opinions if you seasoned professionals as to the imagined performance of such an aircraft. Gimballock.

Okay, so why are there so few designs that particularly try to address this? Most aircraft that I've seen have quite flat intersections at the wing root. Even the ultra-slippery teardrop-shaped sailplanes don't do a very good job.

So tell me, exactly how big a deal is intersection drag? Would it pay any decent dividends to design a plane where aerofoils/wings/etc join the fuselage at such a gradual rate so as to avoid nearly all intersection drag or is the payoff really not that much compared to the annoyances and overheads involved? Thanks. Gimballock

Thanks, Bob. That's about as comprehensive a response as I could have hoped for! You raise some very good and valid points that I will need to digest and ponder! Stay tuned for further questions. At this time, designing and building my own aircraft is pure science fiction/fantasy, but I'm always mulling over ideas for when the time is right. Until then, I will struggle to get my piddley posterior off the ground by conventional means! Thanks again, Gimballock.

Can anyone tell me which is more likely to give more strength per kg - carbon/glass fibre monocoque (like, say a sailplane or a Jabiru) or a tube steel construction with doped fabric or perhaps even a light fibreglass skin (like a nose cone pod on, say, a Drifter)? Just curious. Thanks. Gimballock.

Kiwi: I should probably qualify that - I am actually, at present, getting a type-conversion to Drifer. Dazza: Yes, I know. I've flown with Ian and (of course) Dave, and also Pete (now at Gympie, I believe) as well. All good blokes that I've had hours of flying fun with!

Yup! You got it. I almost flew at Heck Field when I first came to QLD, but just as I was about to book a flight with Nick Sigley, somebody rendered his aircraft U/S (to say the least!) and so he recommended I fly with Greg Neale at Boonah. I did so for a while and recently I've been flying with Trevor and his guys. Both Greg and Trevor are top-notch pilots and I've learned much from both of them!

Hi GooneyBird, The name "Gimbal Lock" refers to an unfortunate situation that could occur in spaceflight where the "8 ball" (like in my avatar) spins too close to the outer stops. If you actually hit the stops, your 8 ball will become stuck/locked, rendering the highly important instrument utterly useless and cannot be reset/re-calibrated except by engineers on the ground. A bit of a pity if you happen to be in space! This nearly happened a few times during the Apollo 13 mission as Jim Lovell struggled to keep control of the two spacecraft joined together. As for flying Drifters, I believe that at Clifton today, you could possibly get away with a few low-level circuits... but that's about it! But, I'm ringed in with water today, so I ain't goin' nowhere! Gimballock.

Hi Alan, I fly from Clifton. I've also flown from Boonah. My background is originally Sydney, so I was at The Oaks, Camden & Hoxton Park. Where are you? Gimballock.

Hi all, I've only just joined the site, but I've been with AUF/RAA for over 10 years, and GFA for about 12 years before that. I fly Jabirus & Drifters in SE QLD. Take care and fly safe, Gimballock.