Folding Wings, Aircraft Trailers, and Portable Hangars for Inexpensive Storage

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autoreply

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For daily use, I'd have no problem spending 10-15 minutes putting it together.
Most pilots (without an infinite budget) say so. But once they own a plane, absolutely nobody is going to spend 15 minutes of assembly for a short flight, save a few nutcases (I'm one of those).
But it's absolutely critical that it be a one-person job.
Indeed. In ALL circumstances. Rain, gusts, on another airport.
Adding to AR's very useful list:
-- Keeping the overall height of the folded aircraft to something less than 7' allows it to be rolled into most US garages, older small hangars with lower doors (built for TD aircraft). I think the Onex missed the boat by folding the wing panels up rather than pivoting them alongside the fuselage. If you are trailering the aircraft because you don't have a hangar at the airport, where will you work on it? Probably at home, and that may mean putting into a garage periodically. So, low height is good.
For more than one reason. High wings invariably means that it'll roll over with gusts and your trailer will (on the road) be blown over. Either keep the chords levels, or have them vertical, but keep the wings fairly low.


Many people try to design within a certain length, often 19'6". Don't. The Ion (not Icon) LSA is a good example, they ended up with a massive tail. Make the plane a lot longer and you'll end up with a much smaller tail one can easily fit through for example a door.

Since we are building a trailer I see little wrong with making it a bit more complex to help with the handling of the assembly.
I do see - a lot wrong with it. You really don't want separate tools. They break down, can damage wings and tails etc and you still have to "transfer" parts from being attached to the fuselage to the trailer. See the first video in post #2 how awkward that can be. And then, those tools are very expensive and complex. A trailer like in the first video runs at just under 20K US$. For a good reason. People that try to go cheaper have a wing cart that runs out of the rails and thus wreck a wing.
If the plane is going to be designed from the beginning to be stored in a trailer and assembled for each flight it might be good to remember that the plane doesn't have to be pulled down the highway on it's longitudinal axis. There is nothing wrong with travel with the wing span aligned with the road if the fuselage folds or breaks in 2 parts.
Exactly. Or diagonal (Davis DA11). Or vertical, with the span along the direction of driving..
I thought the Onex had a locked/unlocked indicator on top of the wing visible from the ground or cockpit?
So when you damage the hinge point, you have a good chance of equally damaging the indicator/lock connection, giving a false positive. While I like the idea of the Onex, it's clear that they've thought it out well, but never actually worked on disassembling/folding planes on a daily basis. In the real world, it's a crash waiting to happen.
 
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cluttonfred

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It is almost perfect. It is just too heavy for a single place.
Aviator168, too heavy for what? The wing-folding mechanism of the Clutton FRED certainly does add weight, and the plane is quite solid overall, but then again the original prototype still flying after nearly 50 years, which is pretty impressive. Considering that Eric's FRED has been flying for many years now with a Continental A-65, if you wanted to spend the money you could have quite a STOL performerby replacing the VW engine with something lighter but geared like an HKS 700E or even somethign more powerful like a Rotax 912. With a low-geared redrive and a big prop you'd have a Super FRED!
 

Aviator168

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Aviator168, too heavy for what? The wing-folding mechanism of the Clutton FRED certainly does add weight, and the plane is quite solid overall, but then again the original prototype still flying after nearly 50 years, which is pretty impressive. Considering that Eric's FRED has been flying for many years now with a Continental A-65, if you wanted to spend the money you could have quite a STOL performerby replacing the VW engine with something lighter but geared like an HKS 700E or even somethign more powerful like a Rotax 912. With a low-geared redrive and a big prop you'd have a Super FRED!
No really. Take a look at the spec of the whole plane.
 

Doggzilla

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Ive been looking around, and Ive come to the conclusion that its about the same cost to buy a few dozen acres. I have been thinking about 100 acres near a mid sized city in the midwest, which can be found easily within 15 minutes of the town.

That said, perhaps the most economical idea would not be to rent or deal with folding wings, but to do the same thing we do with GA aircraft, but for land. A 2x10 acre field is several thousand feet long, and I have found properties within commuting distance to any location I have searched for, and for under the average cost of a house.

If a dozen guys get together in each city, a grass field, usually accompanied by a house with several rooms and at sometimes multiple sheds, can be had for less than your cable and phone bills. Having a home on site would open up all sorts of other options.

Perhaps what we need is a version of aircraft hostels. We already know GA needs more teamwork and community spirit.
 

autoreply

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Can I ask anybody who's serious about designing them to read those two documents. Well, just look at the pictures in them:
Both dead:
http://www.onderzoeksraad.nl/uploads/items-docs/493/2008011_2006034_PH-626_Valkenburg.pdf

Miraculously survived
http://www.onderzoeksraad.nl/uploads/items-docs/773/2009048_PH-1108_definitief.pdf



Ok. Sailplane-style:

Two options (tongue and fork or two diagonals is almost irrelevant). Either we pin the ends of the spar stubs together (lighter), or we put 2 massive shear pins through them. The advantage of the latter is that, unlike the first option, we don't have to align both wings and the fuselage perfectly before we can put the pin through.

HP24. Note the lift pins in the front and the back and the massive pins through the spar stubs.


La belle Libelle. Note the lift pins fwd and aft and the pins on the spar stubs that lock in the other spar.

Pulling the spars together, after aligning both wings and the fuselage perfectly.


Push-push (like on the Onex) and rotating automatic connections are not suitable for primary controls IMHO. Slop and a lack of feel is unavoidable. The rotating connection in the 2nd picture is for the airbrakes. Aileron via a Wedekind-protected connection.

This is the proper way:

Concordia wing root, airbrakes, flap and flaperon.

The other end, although this is an HP24. Note that one automatic connector still has to be installed.



Compare to 1st picture




Std Libelle tail. Slide it in, vertical lift is taken via the elevator hinge and a single bolt at the leading edge.
 

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gtae07

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By and large I think Autoreply and Vigilant are spot-on with the basic requirements. A few minor points, though:

Locking occurs via a single device, visible on the outside, preferably from the cockpit.
Clarification: Does "single device" mean one lock for the whole airplane, or one lock per surface (e.g., one lock per wing)? Does "visible on the outside" mean the locking mechanism/indicator must be an exterior feature of the airplane, or that the internals of the mechanism must be viewable? I would think a locking mechanism inside the cockpit that is viewable by the pilot while seated and strapped in would be ok... like two captive locking pins, one on each side of the pilot's legs.

Rolling in and out of the trailer should be feasible for a single person. Figure 100 lbs push (less slope if heavier).
Depending on the trailer layout and the aircraft, a boat winch might be useful here (electric or hand-cranked). It might take a minute or two longer to go in or out, but it would be significantly less effort.

Total time from unlocking the trailer to having an airworthy plane (save the pre-flight) shouldn't exceed 150 or so seconds for a pilot that has practiced it a few times.
Is this airplane in the trailer to out and unfolded/locked? That seems a little aggressive, especially for a single person. Three minutes to unload and three to unfold is probably more reasonable for an average person.

Push-push aileron control? All fine. But after 100 hours you'll have more and more slop into the control system, resulting in wear in the automatic connections too.
Some re-rigging every 50 or 100 hours might be necessary, but you're already doing oil changes and (for wooden props) retorquing on that kind of schedule anyway. If the interface is in an easily-accessed location, the adjustment procedure shouldn't take more than thirty minutes or so.


I'd also add that any support cradles (e.g., to hold the ends of the wings if stowed like a Panther or Mustang II) should be storable inside the aircraft, or built into the airframe (like the stow latches on an E-2), preferably without compromising baggage space. This way, you have them when traveling or for those diversion cases.
 

autoreply

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Clarification: Does "single device" mean one lock for the whole airplane, or one lock per surface (e.g., one lock per wing)? Does "visible on the outside" mean the locking mechanism/indicator must be an exterior feature of the airplane, or that the internals of the mechanism must be viewable? I would think a locking mechanism inside the cockpit that is viewable by the pilot while seated and strapped in would be ok... like two captive locking pins, one on each side of the pilot's legs.
One per part (wing/tail etc). In that Stemme for example, I'd have a fwd/aft moving locking pin that's kept aft by a few springs. Turn in a M6 bolt, pull and remove the wing. The only way the pin (painted red) can disappear is when the holes are aligned and it's in the spar, or when the spar it completely out.
Depending on the trailer layout and the aircraft, a boat winch might be useful here (electric or hand-cranked). It might take a minute or two longer to go in or out, but it would be significantly less effort.
It's a recipe for damage. When pushing you feel it when something goes wrong. With a winch you simply break it. Not an issue in boats that are far sturdier, but in very sensitive aircraft I've seen at least one person seen wrecking his landing gear.
Is this airplane in the trailer to out and unfolded/locked? That seems a little aggressive, especially for a single person. Three minutes to unload and three to unfold is probably more reasonable for an average person.
Opening the trailer to having an airworthy aircraft. If I can do a much more complex sailplane (far more parts, much heavier and longer) in half that time, we ought to do it a lot better for a simpler, lighter powered aircraft. It can easily be done and the 10-minute thinking has proven not to work once people actually have to do it.
Some re-rigging every 50 or 100 hours might be necessary, but you're already doing oil changes and (for wooden props) retorquing on that kind of schedule anyway. If the interface is in an easily-accessed location, the adjustment procedure shouldn't take more than thirty minutes or so.
Once you have slop - though highly dependent on your flight envelope - you might run into flutter. The increase in slop and wear goes exponentially, so overseeing it once is probably the last time you do so.
I'd also add that any support cradles (e.g., to hold the ends of the wings if stowed like a Panther or Mustang II) should be storable inside the aircraft, or built into the airframe (like the stow latches on an E-2), preferably without compromising baggage space. This way, you have them when traveling or for those diversion cases.
They always get lost. When you need them... well ;)

Having said that, a composite shape around the tail boom or top of the fin that bolts the wings directly to the tail is probably the simplest way of connecting them.
 

Hot Wings

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I do see - a lot wrong with it. You really don't want separate tools. They break down, can damage wings and tails etc and you still have to "transfer" parts from being attached to the fuselage to the trailer.
Again, I've failed to communicate well. I agree the trailer in the video is only a partial, and less than elegant, solution.

For my part 103 project the wings are light, but the chord is too large to make handling easy. My tentative solution is a counterbalanced arm attached permanently to the trailer that swings out, is attached to the wing (with the plane's fuselage already tied down to the trailer), the wing is then removed, rotated. The arm and wing are then secured to the trailer as a unit. Reverse to assemble. This looks fairly easy to do with an open trailer. Adding a user friendly cover is providing some puzzles.

No tools to lose. The wing is under complete control during the process. I suppose that if one had an unlimited budget the whole process could be automated with servos-n-software. Kind of an Iron Man suit assembly trailer for the plane :gig:

Note: My part 103 span = 24 ft. This might be a problem with typical glider wing spans to the point of needing outriggers on the trailer.

One per part (wing/tail etc). In that Stemme for example, I'd have a fwd/aft moving locking pin that's kept aft by a few springs. Turn in a M6 bolt, pull and remove the wing. .
Are you talking about a pin that is held in place during flight by a spring and then to remove the part the bolt is used to depress the spring/pin? Similar to the adjusting pins in a crutch used with a bent/broken leg?

I've thought about this several times and it would make for some very easy to assemble parts. Gun designers use this method quite often and it has proven to be reliable. Is this method used on gliders with reliability? Do pilots and regulating bodies accept this as acceptable practice?
 
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autoreply

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Are you talking about a pin that is held in place during flight by a spring and then to remove the part the bolt is used to depress the spring/pin? Similar to the adjusting pins in a crutch used with a bent/broken leg?
Pull, not push. See around 4 minutes in this video:
[video=youtube;WRhCO42zuzA]http://www.youtube.com/watch?v=WRhCO42zuzA[/video]
You can do the same for wings, just make the locking/sliding part long enough to go all the way through the spar.

The fifth picture shows exactly such a system:
 

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Dana

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10 minutes to unfold isn't too bad, especially if the plane is already at the airport. For me, the big hassle is hooking up to the trailer and towing it to the airport (which is why I leave it there during the flying season, paying the same as outdoor tiedowns). My Kolb has 7 pins (with safety pins or circlips) and one bolt that have to be installed. The unfolding process is just a part of the preflight, the I do a final walkaround, rechecking all pins (they're all easily visible). The pins are all stored in their normal holes, so it's remove the pin, put the part into position, and put it right back in.

Folding in wind... in my case the wind I can safely fold the plane is about the same I can safely fly in, so it's not an issue. Only once did I fly when it was really too windy, and I got a friend to help fold the plane up again.

I agree that an enclosed trailer is probably a must for most people, unless they're folding to share a hangar.

One thing not mentioned is the desirability of having all folding hardware permanently attached to the plane, no racks or dollies. My plane needs a bracket that doesn't fly with the plane, which could be a hassle if I land out somewhere and need to fold it up until I come back with the trailer. Hasn't happened yet, though.

Dana

Are you still here? The message is over. Shoo! Go away!
 

Rienk

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Originally Posted by autoreply
Pull, not push. See around 4 minutes in this video:

Thanks! That is a complete answer.
I'm not sure what I'm supposed to be looking for at 4 minutes?
Forgive my numskullery, but I don't see a pull vs. push.

I am intrigued by how the horizontal stab is mounted... how is the rudder engaged?
Are there pictures of this assembly? Is there a fail-safe so that you can only lock the stab in place if the rudder is properly engaged?

Maybe this needs to be on another thread, but I would really like to see detailed photos and videos of different Quick ans Safe wing folding systems - does anyone have such for one or more system?


I remember seeing how the HP24 had some neat control connections (I forget how they work at the moment) but I remember thinking that it would be great if those parts could be injection molded, along with the other parts I was considering?
 

mcrae0104

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I rather like this system:


It does have the push/push paddles that Autoreply seems not to be a fan of, but it looks like it should be easy enough to adjust the nubbers when slop begins to develop.
 
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autoreply

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I'm not sure what I'm supposed to be looking for at 4 minutes?
Forgive my numskullery, but I don't see a pull vs. push.
Around 4 minutes into the video you can see such a pin mechanism in action. The picture in post #30 (5th one) shows how this can be implemented in a wing.
I am intrigued by how the horizontal stab is mounted... how is the rudder engaged?
The rudder is permanently attached. Or are you thinking about the elevator? If you're thinking about the elevator, freeze at 3:52. The elevator/stabilizer is hinged around the elevator.
Are there pictures of this assembly? Is there a fail-safe so that you can only lock the stab in place if the rudder is properly engaged?
The brilliance of this system is that it's impossible to do it wrong. You end up with the LE of the stabilizer that's 3" about the fin (and obvious). Mounting it off left/right is impossible (pins are too long)
Maybe this needs to be on another thread, but I would really like to see detailed photos and videos of different Quick ans Safe wing folding systems - does anyone have such for one or more system?
This thread features about half a dozen of those in detail. Read through it and you'll see most of the common systems.
I remember seeing how the HP24 had some neat control connections (I forget how they work at the moment)
See post 25
but I remember thinking that it would be great if those parts could be injection molded, along with the other parts I was considering?
You want metal for the fittings (precision fit, bearing strength of metal vs crush strength of composites). Still, I agree, this could be incorporated in a single composite part with metal tracks.
It does have the push/push paddles that Autoreply seems not to be a fan of, but it looks like it should be easy enough to adjust the nubbers when slop begins to develop.
My concern isn't slop itself, but the potential for flutter. Murphy's law is all too valid and too many people have already be killed by designs like this. Theoretically it's perfectly fine, but in an operational environment it's a recipe for disaster. You're pushing against an elastic spar, elastic fitting and a wing that moves fwd/aft. You're essentially basing your fitting on what in flight is structure that's continously moving around.

There´s a good reason all sailplane manufacturers have converged to only a single design and more than a few pilots have paid with their lives with those lessons.
 

Aviator168

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I rather like this system:

[video=youtube;HTb8uiacKsk]http://www.youtube.com/watch?v=HTb8uiacKsk[/video]

It does have the push/push paddles that Autoreply seems not to be a fan of, but it looks like it should be easy enough to adjust the nubbers when slop begins to develop.
That's very cool.
 
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Topaz

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Ive been looking around, and Ive come to the conclusion that its about the same cost to buy a few dozen acres. I have been thinking about 100 acres near a mid sized city in the midwest, which can be found easily within 15 minutes of the town. ...
Maybe in your neck of the woods, but any land within about 30 miles of me is approximately a $500,000-$1,000,000 an acre. Seriously. And putting up an airport (even a private one) requires more permits than even a lawyer wants to look at. Not an option for everyone.

Having looked at various folding/wing-removal mechanisms extensively in the past, and then coming to be around sailplanes, I have to say that the latter have the best-thought-out systems I've seen. The horizontal tail attachment/control-hookup that Autoreply has posted is pure genius, and it's hard to find a new-manufacture sailplane that isn't using some variant on that system, in my experience.

Ditto for the Libelle wing-attach. You just can't do better than this, if you use a folding "hinge" like the Stemme (which, by the way, was also used by the Bede BD-2). Having a hinge structure separate from the primary spar structure really ought to be mandatory. It's just far too easy to push the wing against the hinge in a direction that unintentionally overstresses the structure. We say we'll be carefull, but it's just far to easy to let it slip that "one time." The weight required to beef up the primary structure against such misuse would probably be more than putting in a secondary "fold only" joint like the Stemme. You're not gaining much by avoiding doing so.
 
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Rienk

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Around 4 minutes into the video you can see such a pin mechanism in action. The picture in post #30 (5th one) shows how this can be implemented in a wing.The rudder is permanently attached. Or are you thinking about the elevator? If you're thinking about the elevator, freeze at 3:52. The elevator/stabilizer is hinged around the elevator.The brilliance of this system is that it's impossible to do it wrong. You end up with the LE of the stabilizer that's 3" about the fin (and obvious). Mounting it off left/right is impossible (pins are too long)This thread features about half a dozen of those in detail. Read through it and you'll see most of the common systems.See post 25You want metal for the fittings (precision fit, bearing strength of metal vs crush strength of composites). Still, I agree, this could be incorporated in a single composite part with metal tracks.My concern isn't slop itself, but the potential for flutter. Murphy's law is all too valid and too many people have already be killed by designs like this. Theoretically it's perfectly fine, but in an operational environment it's a recipe for disaster. You're pushing against an elastic spar, elastic fitting and a wing that moves fwd/aft. You're essentially basing your fitting on what in flight is structure that's continously moving around.There´s a good reason all sailplane manufacturers have converged to only a single design and more than a few pilots have paid with their lives with those lessons.
I understand how the wing spar overlaps work (though I've not learned how to make those composite ends fit precisely in a tunnel).I don't understand how pictures 4,5 and 7 work for the controls - it looks like they are incomplete at the moment?To me, the most important question is, how much does the wing fold and auto control apparati weigh? Probably prohibitive on a 103?How much does it cost to make/buy/install those parts?I really like the concept, but am concerned it's not possible in 103?
 

Topaz

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NOTE: This is a deliberate double-post, from the HSA Tehachapi thread. Same subject is being discussed in both, with the same positions being held.

I'm concerned that too much emphasis is being placed here on an exact number threshold for something like wing-folding. Yes, I agree that ten minutes is probably about the outer limit for a really acceptable mechanism. Yes, I agree that anything more is probably going to result in diminished use of the feature.

But are we really arguing the difference between two minutes and five, across three different threads? For purposes of this discussion (in all three threads), at this entirely nebulous point in the "design" of a series of completely hypothetical "cheap" aircraft, can we call it sufficient that the target goal for wing-fold is approximately five minutes, with two being the ultimate goal and ten being the threshold of "unacceptable"?

I hate to see the conversation bog down in such minutiae, when there are larger issues that still need to be addressed.
 

Rienk

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NOTE: This is a deliberate double-post, from the HSA Tehachapi thread. Same subject is being discussed in both, with the same positions being held.

I'm concerned that too much emphasis is being placed here on an exact number threshold for something like wing-folding. Yes, I agree that ten minutes is probably about the outer limit for a really acceptable mechanism. Yes, I agree that anything more is probably going to result in diminished use of the feature.

But are we really arguing the difference between two minutes and five, across three different threads? For purposes of this discussion (in all three threads), at this entirely nebulous point in the "design" of a series of completely hypothetical "cheap" aircraft, can we call it sufficient that the target goal for wing-fold is approximately five minutes, with two being the ultimate goal and ten being the threshold of "unacceptable"?

I hate to see the conversation bog down in such minutiae, when there are larger issues that still need to be addressed.
Preach it, brother!

I'm not so much concerned about the time, as the "weight".
I need to find a wing-fold, auto-control system that can work in a legal ultralight (but it would eventually be useful for the Solo as well).

Not sure which thread to continue inquiring through...
 
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