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Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by rtfm, Dec 28, 2010.
I'm not following that. If it's possible to sketch it, I would be grateful.
Pictures or a link to pages from the catalog that you can order these from would be great too. I have been looking for "sailplane connections" on the internet in hopes of finding a picture but have had no luck.
Every manufacturer, me included, pretty much makes their own automatically connecting control hardware. I tried to buy autoconnect funnels and bellcranks from a couple of different European manufacturers, but none were interested in selling any that were not already packaged in a sailplane. So I designed, tooled, and fabricated my own.
Thanks, Bob K.
Post 35 contains a topic with lots of pictures etc, it's all there.
Envision a push-push paddle (like on the Sonex), with a hollow receiver on one side and a pin on the other side, both perpendicular to the paddle. One slides into the other, you'll have to re-align the hinge points etc, but then you have a fool-proof system.
Hi Bob, I followed your build when you made those parts.
Are you going to be any different than the companies you mention, and provide such parts?
Are you willing to share any drawings of what you did?
I'd like to contemplate ways to cheaply mass produce such parts, so that places like Aircraft Spruce could sell them to potential builders.
(not sure it's possible, but worth a look?)
I'm guess that those companies don't want to supply their hardware because of possible liability of their well designed solution being installed out of context by someone else. Good pictures and drawing seem to be in short supply as well.
Hi , Thanks to everyone for your thoughts and ideas. This group is indeed a great resource.
I think I have figured out a way to rig the aileron cables. It is probably going to be an independent cable loop for each aileron contained inside each wing. That makes it a total of 2 loops for 2 wings.
A 3 rd cable loop resides inside the fuselage just aft of the pilot. The 3 rd loop is controlled by the stick.
2 rigid rods attach 3rd loop to either wing cable loop. Dis-assembly of wings will only require these 2 rigid rods to be detached from the inside fuselage cable-loop. 2 nuts on the inside fuselage cable-loop to be loosened, and the connecting rods disconnected from the inside fuselage loop. These nuts connect the rigid rods from the inside loop to the in-wing loops. ( The rods remain connected to the wing loops permanently. )
This means all 3 loops are always held taut - wings attached or wings taken apart.
It involves 3 pulleys in each wing loop, and may be 4 pulleys in fuselage loop.
When wings are taken apart, once the 2 connecting nuts are loosened and the steel rods disconnected from the inside fuselage loop, a small steel connecting rod will protrude out of each wing , (sticks out may be about 12 inches). I need to make sure this rod is protected from damage / loads when wings are out.
I know this can be confusing without a diagram, but it looks workable.
My earlier challenge was how to design a cable system because there will be some cable connection from inside fuselage to inside of each wing. And while taking out the wings, the cables may become slack, and fall off the inside-wing pulleys. With 3 separate loops all held taut in place even with wings removed, this is no longer a problem.
I might take a few months to reach this stage of rigging. If it works properly after I rig it, will post a few pictures.
Thanks for all the suggestions.
I'm not sure that there really is a viable market for auto-connect hardware outside of sailplanes. I could be convinced otherwise, though.
Thanks, Bob K.
I think that they should be used in every removable wing configuration - to avoid complicated cabling attempts like mentioned above. You're right, the market will probably be small, and not a source of income - more a means of advancing inclusion in general aviation and improve safety overall. Thus, more of a legacy to leave than a profit to make.
I disagree that "the market will probably be small, and not a source of income". Well, not a source of income may be true, after all this is aviation. Because it is aviation related the market will be small also. I see your point, hope you see my perspective.
However, I do think that folding wings for the recreational aviation market will become more comonplace do to storage limitations. Once the commitment is made to fold the wings the auto connect or perhaps eliminating the need for auto connect will come to dominate.
Are there any Navy folding wing aircraft that disconnect the controls when the wings are folded?
I haven't been following this thread in detail. Hope I did not repeat prior details. Also, the cable system discribed above sounds complicated. I have experiance with push pull quick connects used by glider manufacturers. Not automatic but they do work. Other systems that work well are the teleflex type connectors with a quick pin. The best systems use a torque tube with automatic connection.
I like the Sea Era system for an ultralight (home made teleflex) used for both aileron and flap/wing incidence operation but again not automatic. It uses a small bolt (7/16 wrench) for the connection. Don't recall if it was discussed here on the Sea Era thread. I can post more if wanted.
Check out the system that Bob used, which has become common for sailplanes (maybe he'll be kind enough to post a direct link).
I like it a lot, and believe that if the parts were readily available, more designers would consider using removable wings, and thus such parts.
I would think that they could work fairly easily in folding wings as well.
I don't even think it's an issue of the parts being available or not. The majority of light airplane designers have simply never even seen them before. A good technical writeup with lots of pictures and a video or two would sell the concept. You could sell the ready-made sockets and other components on the side, but the biggest factor in making them widely used will just be getting the word out.
But having ready made supply would be a good idea concurrently.
I would very much like to delve into how they accomplish it especially the control linkage aspect of it.
=very good solution !
I'd check around to see if anyone near you has a Glastar and look at how they did it. A friend of mine had one and it seemed to be easy to fold. Something
to consider is how wide the unit will be overall when the wings are folded. Some airplanes end up being too wide to be trailered even with the wings folded.
Also the width of the tail on whatever airplane is being considered may be a factor. Some of the tail surfaces are wider than allowable road travel limits.
Also, consider the weight of the wing when it contains fuel, which could affect the ability of one person to fold a wing, and the whether the leverage of
having one wing folded while the other is still extended
might cause the airplane to tip over.Some of the Zeniths fold, but not as easily as a Glastar. Folding Wings Option for storage and trailering: Zenith STOL CH 750 light sport utility kit plane - YouTube http://www.youtube.com/watch?v=FPD8xAZsDek
There are several folding mechanisms shown in this thread: https://www.homebuiltairplanes.com/...ers-portable-hangars-inexpensive-storage.html
I folded lots of naval helicopters (Sikorsky Sea King), but only a handful of fixed wing naval aircraft. I remember the Grumman Tracker as having a pair of mating bell-cranks at each wing-fold joint. The outer wing bell-crank was "male" and nested into concave "female" bell-crank in the wing-root. Once the wing was extended, both hinge-lines coincideded, so the pair of bell-cranks moved as one.
If the fuel tank is close to the hinge (e.g. root of outer wing panel) it shoud be easy to fold by hand.
May I suggest a simplified version of your 3-cable design?
Bolt an outer-wing pulley to a wing-spar so that it overlaps into the wing root by at least 1 pulley diameter. Machine a wedge onto the aft face of the pulley.
Meanwhile, cut a wedge-shaped groove into the forward face of a fuselage pulley. When you extend the wings, the two pulleys will overlap, mesh and drive each other.
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