Is there a cheapest/lightest/simplest wing structure other than aluminium tube and fabric?

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

Gregory Perkins

Well-Known Member
Joined
May 25, 2019
Messages
192
Location
Atlanta
Re- the Birdman TL,
I believe the structure failed in non-aerobatic flight on one or two of them, so I'm nto sure the term "well designed" can withstand a lot of scrutiny. It might have been good for a university demonstration or record-setting machine, but to have advertised the Birdman as being safe enough for everyday use in any range of real-world conditions...?

That being said, I am fascinated by this aircraft just like so many others have been, and the thought of engineering carbon pulltrusions to stiffen or strengthen the structure in the more delicate areas is appealing.

It is true the first version Birdman TL crashed at an airshow in Houston ( I think)
killing the designer and the company. Later, a new company headed by the former accountant re engineered (professionally) and increased the thickness of the wing skins for more robust ground handling and increased the size of the engine and converted to a V-Tail and round cone rear fuselage arrangement. Damage to the leading edge D-cell attributed to rough ground handling was deemed the cause of the crash. The newer heavier version ( from 100 to 122 pounds empty) received many positive reviews. The wing structure does remind me of the VJ-23 and a little of the
ULF-1. While both the VJ-23 and ULF-1 were powered and modified to include
wheels, I believe those versions were heavier than 122 pounds and perhaps not engineered as well at those heavier powered weights. One of the things that most intrigue me is the ground handling assisted by extending your legs. I believe takeoff and landing operations were conducted solely with the wheels. One of the pictures
shown "filename" refers to the Sports Avaition magazine review.
 

J.L. Frusha

Well-Known Member
Joined
Feb 17, 2006
Messages
985
Location
Luling, Texas
Tensegrity wing with cap-strips as formers weighs about half what a normal wing does. Instead of steel cables, use an Aramid Fiber 'rope'* for tension (~15X stronger and lighter), then use wooden dowels as the strut pieces, or (even better) possibly CF wrapped wooden dowels...


*UHMWPE (ultra high molecular weight polyethylene) rope is an extremely tough plastic with high abrasion and friction resistance. It’s a superior alternative to steel wire rope and is used in maritime, lifting and high friction industries. It’s chemically and physically identical to Dyneema.

1642622145101.png

1642623564129.png
 
Last edited:

ypsilon

Well-Known Member
Joined
Mar 1, 2016
Messages
307
Location
Austria
Hi Oriol,

Light and cheap are often contradicting, but since you are interested in low performance designs, also have a look at Kalbermattens WhoopyFly
https://www.youtube.com/watch?v=C6CvycZux0E

The concept could be interesting, his implementation is problematic, but it results in a system that is light and foldable.
 

J.L. Frusha

Well-Known Member
Joined
Feb 17, 2006
Messages
985
Location
Luling, Texas
Jeeeez Frusha, that's almost as many turnbuckles as there are in a Tiger Moth!
Even worse... They didn't use locking nuts, or pre-stretched leader, so they played Hell keeping tight. They thought they had "turnbuckle creep" but testing the turnbuckles didn't show that. smdh

Some people don't have the sense to come in out of the rain, or ask for help. I could've told them what their problem was. That's why I'll go with the lighter UHMWPE rope.

Oh, btw, that's the misleading pic. Here's the web as drawn for actual construction...

1642630924953.png
 

oriol

Well-Known Member
Joined
Dec 31, 2009
Messages
836
Location
Barcelona, Spain.
Hi Ypsilon!

One of the challenges is to come up with something that can rival with a parafan. I perhaps can get something with slightly better performances, but probably not something that can fold as good.

Hi J.L. Frusha!

Has this foldable wing has been tested on a RC or full scale aircraft?

One the of the shop mates was selling a foldable structure very similar to that one. The thing fit on a bacpack, when deployed it served as a wall in where to hang posters. It was intended as a quick and easy separation wall for stands and events.

It might be possible to come up with something like that for a wing but it would probably take a lot to get it ready for flight; cover it with fabric attach all the nuts and bolts etc.

Perhaps I am wrong though. In any case it is good that someone is trying to do something that has not been tried before!

Hi Henryk,

Prospective concepts did some cool intents of what seemed a sort of revival of the inflatoplane concept, but it seemed that the projects did not went much further than the pictures on their website.

Oriol
 
Last edited:

J.L. Frusha

Well-Known Member
Joined
Feb 17, 2006
Messages
985
Location
Luling, Texas
Hi Ypsilon!

One of the challenges is to come up with something that can rival with a parafan. I perhaps can get something with slightly better performances, but probably not something that can fold as good.

Hi J.L. Frusha!

Has this foldable wing has been tested on a RC or full scale aircraft?

One the of the shop mates was selling a foldable structure very similar to that one. The thing fit on a bacpack, when deployed it served as a wall in where to hang posters. It was intended as a quick and easy separation wall for stands and events.

It might be possible to come up with something like that for a wing but it would probably take a lot to get it ready for flight; cover it with fabric attach all the nuts and bolts etc.

Perhaps I am wrong though. In any case it is good that someone is trying to do something that has not been tried before!

Hi Henryk,

Prospective concepts did some cool intents of what seemed a sort of revival of the inflatoplane concept, but it seemed that the projects did not went much further than the pictures on their website.

Oriol
Not foldable, as far as I know. Just keeps the solid pieces in compression and the cables in tension.

Has been tested at something like +1-2G and -1G. I'd have to test it way beyond that, but schools have tiny budgets for experimentation.
 

Victor Bravo

Well-Known Member
Supporting Member
Joined
Jul 30, 2014
Messages
10,881
Location
KWHP, Los Angeles CA, USA
The answer to the original post's question IMHO is no... a well thought out aluminum tube based wing is going to give you the best combination of cheap/simple/light. Especially if you want there to be some significant number of examples out there flying safely. The classic Quicksilver style ladder frame wing will win this competition, even though it is not the most elegant..... until you put parts count and assembly time into the equation, at which time it becomes pretty darn elegant.
 

cluttonfred

Well-Known Member
Supporting Member
Joined
Feb 13, 2010
Messages
9,533
Location
World traveler
I'd also put the Sky Ranger microlight out there as a great example of the simplicity that can be achieved with a basic ladder frame wing and similarly simplified fuselage of straight tubes and bracing wires. The hitch for the amateur builder trying to use this system for scratch-building rather that kit assembly is that there is a lot of hardware and small fittings far cheaper to track down and buy in bulk for kits than in small quantities for an single airplane. Tube and gusset construction with pulled rivets seems easier to pull off for scratch building but you could still use the same ladder frame approach.

sky ranger.png sky ranger structure 1.png sky ranger structure 2.png

The answer to the original post's question IMHO is no... a well thought out aluminum tube based wing is going to give you the best combination of cheap/simple/light. Especially if you want there to be some significant number of examples out there flying safely. The classic Quicksilver style ladder frame wing will win this competition, even though it is not the most elegant..... until you put parts count and assembly time into the equation, at which time it becomes pretty darn elegant.
 

cluttonfred

Well-Known Member
Supporting Member
Joined
Feb 13, 2010
Messages
9,533
Location
World traveler
Even NASA plays with inflatable dolls...

Inflatable structures make a lot of sense for zero gravity or microgravity space stations launched in small packages that can then expand to create more volume. I am actually surprised that there haven't been modular space stations of inflatable units that look like ping pong balls stuck together.

On earth, inflatable aircraft seem less appealing due to the high quality manufacturing and fairly high inflation pressures needed to work. Something like the ML Utility or more modern designs that use a cart-like fuselage pod suspended beneath an inflatable wing could working as a kit plane with the inflatable wing supplied ready to fly (after inflation) and the cart amateur-built.

1642665003936.png 1642664950251.png
 
Last edited:

Aesquire

Well-Known Member
Joined
Jul 28, 2014
Messages
3,263
Location
Rochester, NY, USA

Check out the Tech section of this page for a hint at the hidden complexity.

not an endorsement! I've not flown this brand or model. It was a random pick to show construction details, only.

looks nice. It's a technology that requires skill and precision to do properly, but that's also true of other building techniques,

Re: aluminum tube ladder style...

I prefer bolted construction that uses saddles and properly installed anti-crush tubes, over gusset, for most applications, but it is more expensive to gain ease of repair, and bolted construction requires stringent inspection and disassembly because of more focused loading. TANSTAAFL
 
Top