European ULM like a Piper in wood (new design)

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antoniv

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Jun 21, 2006
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Dear friends, I wish to explain my design project. I am industrial designer specialized in wooden boats and amateur aircraft builder .

I wish to longtime undertake the personal challenge of designing my own plane. I do not intend to reinvent the wheel, I am aware that only a few chosen can bring something new to the aviation.

The plane that I need and desire is a Super Cub, but I have only flying license for European ultralight category. 472 kg MTOW.

It is for this reason that my challenge is to design an ultralight with aesthetics, performance and stol capabilities from Piper aircraft. Using basically for construction wood and composites.

I know there are many designs like the Piperin wood, such as Light Miniature, Fisher or Ragwing . It is not my intention to belittle them. This is my personal challenge and I think it's a good idea to build on good design as the Piper that has inspired many designers before me.

For now I have only made the first approach dimensions, attached two pictures so you can see the whole.

Wingspan: 9.44 m (30.84 ft)
Length: 6.20 m (20.34 ft)
Wing area: 13 m2 (140 ft2)
MTOW 472 kg (1040 lb)

See the 3 view's in the attachments

View attachment PiperULM_plantallado_alado.pdf View attachment PiperULM_ladoalado_perfil.pdf

Hope you like it and want to read your comments. And apologies for my English
 

fly2kads

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I understand that personal challenge, and I am sure many others on this forum will, as well.

It looks like you are off to a good start! I like that the enclosed cowling is reminiscent of the J-4 Cub Coupe. Some chrome trim would give it a deluxe, retro look! I also like the upward slant to the lower edges of the side windows. I think that gives a modern touch to the appearance.

I am sure the ULM restrictions are challenging, particularly the weight limitations. It seems too easy to wind up with an aircraft with a limited useful load.

Good luck with your project!
 

Dana

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Looks nice! Is it single seat or two seat?

Two thoughts: Take a look at the Taylorcraft. Taylor designed the original Cub, and after his split with Piper, came up with the Taylorcraft BC series, which was a better performer than the Cub in almost every way on the same horsepower. He did it by careful attention to drag reduction (even though the side by side arrangement is wider than the Cub's tandem seating), and by using a more efficient airfoil (NACA 23012 instead of the Cub's USA35).

Also, you show the wing struts joining the fuselage bottom at the rear of the landing gear. Most likely, the front gear leg is the primary, and that's where the fuselage's strong point will be. Typically the front strut carries most of the load, while the lighter rear strut mainly resists wing twist.

Dana
 

antoniv

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Thank you for your words and advice.

It is a two-seater plane. At first I opted for the tandem configuration but it is difficult to maintain a margin of displacement of CG required fot the tandem in a small plane.

So now is tandem settings side by side like the taylorcraft or J4.
 

BJC

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Looks nice! Is it single seat or two seat?

Two thoughts: Take a look at the Taylorcraft. Taylor designed the original Cub, and after his split with Piper, came up with the Taylorcraft BC series, which was a better performer than the Cub in almost every way on the same horsepower. He did it by careful attention to drag reduction (even though the side by side arrangement is wider than the Cub's tandem seating), and by using a more efficient airfoil (NACA 23012 instead of the Cub's USA35).

Also, you show the wing struts joining the fuselage bottom at the rear of the landing gear. Most likely, the front gear leg is the primary, and that's where the fuselage's strong point will be. Typically the front strut carries most of the load, while the lighter rear strut mainly resists wing twist.

Dana
+1 0n the Taylorcraft.

I agree that it looks unusual, but having the strut(s) attach aft of the usual location sure make it easy to enter / exit the aircraft. And one can grow to actually like the looks. :) Also facillitates folding the wing.

Here is an airplane that is really easy to enter / exit.

019.jpg


BJC
 

bmcj

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It looks to me that attaching the door to the rear gear mount might ge in the way of such a large door. The forward attach point might be better. However, the gear location may change as the design detail is worked out (once weight distribution is known).
 

cluttonfred

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Very pretty lines, I like it. I agree that the mid-mounted V-strut is perhaps not ideal, better to go forward to make the forward strut the primary one directly in line with the main spar and the rear one just for torsion, or aft to put the attachment point in vertical alignment with the rear strut to hinge for folding or just to facilitate cabin access. I prefer the lattter arrangment, the Luton Major and Fisher Horizon 1 and 2 are good examples.

luton.jpg fisher.jpg
 

DangerZone

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Dear friends, I wish to explain my design project. I am industrial designer specialized in wooden boats and amateur aircraft builder .

I wish to longtime undertake the personal challenge of designing my own plane. I do not intend to reinvent the wheel, I am aware that only a few chosen can bring something new to the aviation.

The plane that I need and desire is a Super Cub, but I have only flying license for European ultralight category. 472 kg MTOW.

It is for this reason that my challenge is to design an ultralight with aesthetics, performance and stol capabilities from Piper aircraft. Using basically for construction wood and composites.

I know there are many designs like the Piperin wood, such as Light Miniature, Fisher or Ragwing . It is not my intention to belittle them. This is my personal challenge and I think it's a good idea to build on good design as the Piper that has inspired many designers before me.

For now I have only made the first approach dimensions, attached two pictures so you can see the whole.

Wingspan: 9.44 m (30.84 ft)
Length: 6.20 m (20.34 ft)
Wing area: 13 m2 (140 ft2)
MTOW 472 kg (1040 lb)

See the 3 view's in the attachments

View attachment 37604 View attachment 37605

Hope you like it and want to read your comments. And apologies for my English
A properly designed wooden wing does not need struts, it will exceed in both strength and stiffness most metal and cloth wings, even many composite ones.

What kind of engine and power did you plan to use? Becuase the airframe will probably have to be built around the engine, the other way around moght show some problems at a later stage.
 

Dana

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A properly designed wooden wing does not need struts, it will exceed in both strength and stiffness most metal and cloth wings, even many composite ones.
Perhaps, but a full cantilever wing requires a solid spar carry through, which can interfere with headroom in the cockpit.

Dana
 

DangerZone

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Perhaps, but a full cantilever wing requires a solid spar carry through, which can interfere with headroom in the cockpit.

Dana
Good point. ;)

I've seen an interesting high wing design with an engine mounted in the back so the pilots would be in front of the wing spar. This increased the cockpit vision to helicopter-like panoramic view and the props were in the back resulting in less noise. I forgot the name so if anyone remembers feel free to post pictures or name it.

There are other high wing aircraft besides Piper Cub that can be used as a model, the STOL Highlander or Zlin Safari come to mind.
 

Jan Olieslagers

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DangerZone's question is important: what engine will you be using? Some advocate designing the plane "around the engine".

PS and don't apologise about (the quality of) your English, there is much worse around here.
 

fly2kads

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Per the data on the side view drawing, it's the Rotax 912:

Piper ULM
Envergadura: 9.40 m
Longitud: 6.20 m Sup. alar: 13 m2
Cuerda: 1.42 m
Alargamiento: 6.8 m2
Perfil: Clark Y - GA ?
Diedro: ž 3deg
Peso en vacio: 250 kg a 280 kg
Peso maximimo: 470 kg
Motor: Rotax 912 80 cv
Ancho del tren: 1.80 m
2 plazas lado a lado
Ancho cabina: 1.1 m
 

DangerZone

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Per the data on the side view drawing, it's the Rotax 912:

Piper ULM
Envergadura: 9.40 m
Longitud: 6.20 m Sup. alar: 13 m2
Cuerda: 1.42 m
Alargamiento: 6.8 m2
Perfil: Clark Y - GA ?
Diedro: ž 3deg
Peso en vacio: 250 kg a 280 kg
Peso maximimo: 470 kg
Motor: Rotax 912 80 cv
Ancho del tren: 1.80 m
2 plazas lado a lado
Ancho cabina: 1.1 m
With such a large surface area and the mentioned airfoil, this might be slightly underpowered for the optimistic weight of 280kg. Many airplane owners try to sell similar used aircraft because they are only fun for an hour or two. Compare that to a Piper Cub with slightly more weight at 150HP&+ and we all get the picture, the Piper fun effect lasts forever. It would be cheaper and more time efficient to buy an used 80HP taildragger and see what it's like. But that's just me, I like to enjoy flying and fool around short landing strips.
 

antoniv

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Joined
Jun 21, 2006
Messages
24
Dear friends was a great surprise to find all your answers I've been a few days out of my house.

I want to thank all for your comments. For now all are sketches and hopefully improve with your advice.

@BJC @bmcj @cluttonfred: I will study the structural possibilities for optimizing the best position of the struts.

@orkaan: Your plane is very nice, did not know him before. For me it was a big surprise, a good job and very professional. Will be for me a good inspiration.

@DangerZone: Right now I'm co-owner of a Tecnam P92 and enjoy the flight for about 4 hours per month. But now, I also want to enjoy the pleasure of designing and building.The wing area and the maximum power that I have chosen is in line with many ultralight flying in the european fields of flight.

I want to get a design of airplane for a more relaxed flight than the P92. For access to airfields least prepared. As an example I can mention:

Zling Savage
Best off Skyranger
Rans S-6 Coyote ... And many more


I promise that this week will post updates on the aerodynamic calculations.


thank you very much
 
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