Any conventional 2-place plans-built acft using hot-wired composite wing constrction?

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Vigilant1

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Does anyone know of presently available plans for two-place non-canard aircraft utilizing the Rutan hot-wired wing fabrication method? Thanks.
 

AVI

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

The January 1996 issue of Kitplanes magazine featured an all-composite plans-built aircraft with hot-wired wings called the Air Master.
Plans were offered for sale, but it seems that the project faded away into oblivion after the death of the designer, Jerry Stallings, in a plane crash.

The info pack showed plans similar in style to the LongEZ. The construction was similar with slab sides and floor, and hotwired wings. Stallings used BIAX and TRIAX. The contact info back then was:

The Airplane Builders
7822 Gulfton
Huston TX 77036
713 780-1123 (plans were $500)

The contact info may not be of any use today, but perhaps there's a set of plans floating around somewhere, or maybe there's a chance that the design might be resurrected.
 
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wsimpso1

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

Search HBA on Airmaster, and you will find some stuff I wrote up on it. I tried to keep the design and plans alive, but Jerry had never gotten anywhere close to having a set of plans, and it was woefully underdesigned too.

I don't know of any other non-canard scratch built fiberglass birds. That is why I designed and am building my own. As I got into things, I ended up designing and building a molded airplane, as that works best in conventional birds... I do have hotwired molds for wing skins and hotwired cores for tail and control surfaces.

Billski
 

Vigilant1

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

AVI,
Thanks for the lead to the Airmaster. It was a good looking airplane, and the only design I've heard of with a conventional wing/tail layout with a wing made via the hot-wired foam method.

Billski,
Your previous writeup on the Airmaster was very revealing--glad I didn't go down that road. Ref your other comments on hot-wired foam wings and your decision to vary from that in your own design--why? Is it just too heavy to leave that foam there rather than go with built-up spar/ribs (seems it would be close to a wash after considering the need to glass both sides of the skins, etc). Or, is the sacrifice of the wing fuel storage the factor? I'm just surprised that only Burt and other designers of canards have gone with the hot-wired foam method, I'm sure there's a good reason for this. It's attractive to me as it would appear to cut construction time considerably.

Thanks to all for the input.
 
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wsimpso1

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

I am the first to advise doing calculations of weight when folks suggest hollow is lighter. Same spar and glass outside, more glass inside, foam and glass ribs inside, flanges, and so on. All of that extra glass and epoxy can weigh a lot more than some foam at 2 lb/ft^3... Until you get to some pretty large thickness (in 2 seaters), solid core is lighter. Tails and control surfaces on the Catbird and Boomerang were all hotwired cores (talked with the guys who are flying them now and confirmed it). Rutan and company used hollow wings only where they were storing fuel and landing gear... Me too. Fixed vertical and horizontal stabilizers, rudder, elevators, flaps, and ailerons are all hotwired cores as that is the lightest way to get to strength. For my wings, solid core would have saved a few pounds on the wing, but that is not all that matters. Optimizing individual items can sub-optimize the airplane...

Fuel in the fuselage has never sounded like a great idea: it would need to be on CG where the airplane is already crowded with people and bags and control systems or send the people forward and the bags aft and give all sorts of difficulty with CG management; split with some fuel aft and some forward and the attendant CG issues; then there is the issue of 65 gallons of gas mingled with people in a crash. So, the wings are hollow and fuel takes up a lot of the outer panel wing volume. There is an equipment bay for aileron hardware and pitot-static stuff, plus the Wittman legs and other stuff fit in the hollow stub wings. To put the fuel in the fuselage would have weighed something too, so I figure the airplane is no heavier, has less wetted area, and is way more usable for travel.

Billski
 

AVI

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

AVI,
Thanks for the lead to the Airmaster. It was a good looking airplane, and the only design I've heard of with a conventional wing/tail layout with a wing made via the hot-wired foam method.

Billski,
Your previous writeup on the Airmaster was very revealing--glad I didn't go down that road. Ref your other comments on hot-wired foam wings and your decision to vary from that in your own design--why? Is it just too heavy to leave that foam there rather than go with built-up spar/ribs (seems it would be close to a wash after considering the need to glass both sides of the skins, etc). Or, is the sacrifice of the wing fuel storage the factor? I'm just surprised that only Burt and other designers of canards have gone with the hot-wired foam method, I'm sure there's a good reason for this. It's attractive to me as it would appear to cut construction time considerably.

Thanks to all for the input.

Vigilant1:
Have you checked out the KRSuper2? Plans built, all-composite - and you don't even have to pay for a set of plans. KR-Super2

It's a modern composite redesign of the Rand Robinson KR2 without the wood truss fuselage. I'd take a close look at it. While you're on that site, click onto Mark Langford's KR2 site: Mark Langford's KR2S Lots of good stuff there.

Then there's the American Affordable Aircraft Vision, also plans built, composite with "Fold-A-Plane" construction, similar to that of the KRSuper2.
Vision Aircraft
 

wsimpso1

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

The KR2 (and derivatives) and the Vision (and deriviatives) do not have hotwired core wings, but are built up wings...

The Airmaster used hotwired cores, and stored fuel in the wings, but failed in that fuel diffused into the styrene foam and melted it, ultimately causing Jerry Stallings to attempt to replace the foam with two part PU foam. From doing post-crash analysis, his attempts were also bad news, and may have led to the double fatality crash of that airplane. Polystyrene foam does not belong anywhere near fuel. The known foams that are fuel-safe are either not readily hot-wired or emit poisonous gases when cut with a hot wire. Unless new plastics are invented that are both fuel safe and readily hotwired, massive foam core wings that are also fuel tanks are not really in the cards...

Billski
 
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pwood66889

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

"... the project faded away into oblivion after the death of the designer, Jerry
Stallings, in a plane crash."
Funny how that tends to happen...

"Optimizing individual items can sub-optimize the airplane..."
Thanks, Billski, for reminding every body about global vs. local optomization.
What he says is true, folks.

"... then there is the issue of 65 gallons of gas mingled with people in a crash."
Always a risk. "The only time there is too much fuel on board an airplane is
when it is on fire." Got 6 gallons in a header myself.

Again, thanks Billski. Excellent comments and super wisdom.

Percy in SE Bama
 

cattflight

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

The KR2 (and derivatives) and the Vision (and deriviatives) do not have hotwired core wings, but are built up wings...

The Airmaster used hotwired cores, and stored fuel in the wings, but failed in that fuel diffused into the styrene foam and melted it, ultimately causing Jerry Stallings to attempt to replace the foam with two part PU foam. From doing post-crash analysis, his attempts were also bad news, and may have led to the double fatality crash of that airplane. Polystyrene foam does not belong anywhere near fuel. The known foams that are fuel-safe are either not readily hot-wired or emit poisonous gases when cut with a hot wire. Unless new plastics are invented that are both fuel safe and readily hotwired, massive foam core wings that are also fuel tanks are not really in the cards...

Billski
Any reason either the KR2S or the Vision couldn't be built with hot-wired wings, if properly engineered? And by "properly engineered" I suspect one would have to find a way to build in either an aluminum or PVC-based fuel cell.
 

wsimpso1

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

Once you make that change to either the Vision or the KR2S, it is no longer a Vision nor a KR2S, but then becomes an airplane that you have to be willing to design, detail, work out the construction, build and test fly. Ready to do that?

Billski
 

Vigilant1

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Re: Any conventional 2-place plans-built acft using hot-wired composite wing constrct

Any reason either the KR2S or the Vision couldn't be built with hot-wired wings, if properly engineered? And by "properly engineered" I suspect one would have to find a way to build in either an aluminum or PVC-based fuel cell.
Yes, maybe a Vision with the first 24" of wing on either side made of PVC foam sandwich containing fuel, with hot wired removeable/foldable wings outboard of this (the overall width of fuselage (44") and wing stubs would be under 8 feet, allowing the acft to be put on a trailer and towed without special permits). How much fuel? A WAG (without looking for my copy of the plans): 48" wing chord, figure (after flaps and spars) 32"w available for fuel. Maybe 3" (??) high internally (average from LE to flaps)= 1152 cu in for fuel per foot of wing. That's 5 gallons per foot of wing, so 20 gallons in both stubs, without a header tank, fuel-proof fuel cells the hot-wired section of the wings, fuel under the seat, etc. That's a rough guess, but if it's close, that might be sufficient for an airplane designed for 100-125 HP (burning approx 6 GPH). For cross-country use an aux tank would be needed. (10 gallons in a portable polyethylene tank close behind the seat, periodic gravity feed to the wing stub tanks to top 'em off?)

But, as Billski points out, a big change like this would require re-engineering and retesting everything. The payoff would be an acft that was considerably quicker to build and cheaper to keep (trailer it home, or pack several into a single hangar at the airport and share the rent).
 
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