oriol
Well-Known Member
Hi!
I am having a hard time, thinking and finding examples, of how cross beam structures work? By cross beams I mean, a twin engine mounted on the wing, like a Piper seneca, where the engine mount is bolted at 90º with respect to the main spar. Or a double tail aircraft, like the Vampir or the P 38, in where the tail crosses the main spars.
I understand that if you compute the loads, then you can size the parts accordingly. But it is hard to visualize possible simple arrangements, that come to mmind?
If thinking alu, the structure might look similar to a rivetted bridge. I googled to find examples of alu Piper twin engine wings cuttaways. I found this interesting picture below, of a Piper Aztec. It is clever how they mix alu rivets and a tubular weld structure, to carry the loads to different spots, to avoid load concentrations.
If thinking wood, it seems a bit more challenging. It depends if the wing is covered with fabric, or if the wing has a wood skin. A similar approach to that of the Piper Aztec might work, I guess. Mixing tubes and metal plates.
The Mosquito seem to be a good example. The engine mounted is bolted to the main spar, and below a tube connects it to the rear spar. At the same time, hard points are used for the landing gear. It seems that integrating metal plates in a wood wing structure, like in the second picture, might not be trivial.
If the loads are not too high, like in a double tail without engines on the wing. It seems that bolting the tail to the skin of the wing, might suffice. This small drone below, or the civil Cessna Push Pull might be good examples.
If considering a double tail moldless composite aircraft.
I would think that sculpting the aircraft on foam, and reinforcing the main beams, where the loads are concentrated, plus covering everything with glass, might do the trick.
Of course, it is wise not to start a house from the roof.
First compute the loads, and then you will design a proper structure. But any picture, or concept behind cross beam unions, might help to visualize how the loads are transfered among the different parts?
Is there a material that is more friendly, wood versus alu etc, to solve those kind of unions, without having to deal with multiple complex different parts? I realize that being able to draw and play with solidworks, might be of assistance to compare different solutions.
Thanks!
Oriol
I am having a hard time, thinking and finding examples, of how cross beam structures work? By cross beams I mean, a twin engine mounted on the wing, like a Piper seneca, where the engine mount is bolted at 90º with respect to the main spar. Or a double tail aircraft, like the Vampir or the P 38, in where the tail crosses the main spars.
I understand that if you compute the loads, then you can size the parts accordingly. But it is hard to visualize possible simple arrangements, that come to mmind?
If thinking alu, the structure might look similar to a rivetted bridge. I googled to find examples of alu Piper twin engine wings cuttaways. I found this interesting picture below, of a Piper Aztec. It is clever how they mix alu rivets and a tubular weld structure, to carry the loads to different spots, to avoid load concentrations.
If thinking wood, it seems a bit more challenging. It depends if the wing is covered with fabric, or if the wing has a wood skin. A similar approach to that of the Piper Aztec might work, I guess. Mixing tubes and metal plates.
The Mosquito seem to be a good example. The engine mounted is bolted to the main spar, and below a tube connects it to the rear spar. At the same time, hard points are used for the landing gear. It seems that integrating metal plates in a wood wing structure, like in the second picture, might not be trivial.
If the loads are not too high, like in a double tail without engines on the wing. It seems that bolting the tail to the skin of the wing, might suffice. This small drone below, or the civil Cessna Push Pull might be good examples.
If considering a double tail moldless composite aircraft.
I would think that sculpting the aircraft on foam, and reinforcing the main beams, where the loads are concentrated, plus covering everything with glass, might do the trick.
Of course, it is wise not to start a house from the roof.
First compute the loads, and then you will design a proper structure. But any picture, or concept behind cross beam unions, might help to visualize how the loads are transfered among the different parts?
Is there a material that is more friendly, wood versus alu etc, to solve those kind of unions, without having to deal with multiple complex different parts? I realize that being able to draw and play with solidworks, might be of assistance to compare different solutions.
Thanks!
Oriol
