Advice on building material for a roadable ultralight aircraft

[wrzesinski]

I am dead set on building my own ultralight aircraft and I need some advice on construction materials.

The aircraft has to weigh less than 254lbs [including engine and prop] and has to support itself, and 500lbs worth of pilot, cargo, fuel, instruments, and eventually a rear wheel drive system that will transfer the power from the propeller to the rear wheels so that the aircraft can be driven to and from the airport [the wings will fold]

other than that the design is completely malleable, I can use any engine+transmission that can drive a prop at 2-3000 rpm then gear down and drive at speeds of up to 55mph. I was thinking about using a Honda cmx250c “rebel 250” engine and modified transmission to supply the power because of its reliability and fuel efficiency. On my rebel it can push me, the bike, my fiance, and 50lbs of groceries down the road at 65mph no problem [total weight around 700lbs] and it can do it all while getting 60mpg [and that's WOT, around town it gets more like 80mpg] the problem with that engine is the fact that it is steel construction and weighs 110lbs wet [including transmission and starter] but if you have a lighter engine with comparable power please let me know.

I need help choosing a cost effective yet weight effective building material that will still yield a safe aircraft. I was thinking square aluminum tubing for the body and round aluminum tubing or the wings [since the stress on the wings will be pretty much omnidirectional in flight, and square tubing isn't built for that kind of stress] but if you have a better idea I would be more than willing to try it instead.

I am trying to keep costs down as I am low on cash [but if I have to I will build the craft a little at a time until it is complete] so keep that in mind.

I have started a blog to document my build, it isn't much at the moment but I am working on posting on it fairly regularly.

Here is the link: http://thefreeflightproject.wordpress.com/

again, any help is greatly appreciated!

 

[Valerie Park]

Thanks! For your ultralight aircraft, you should consider using lightweight aluminum alloys such as 2024-T3 or 6061-T6. These materials are strong and offer a good strength-to-weight ratio, making them ideal for applications such as aircraft construction. For the body of your aircraft, you can use square aluminum tubing, while for the wings, round aluminum tubing will be more suitable due to its omnidirectional strength properties. Additionally, you can also look into using composite materials such as carbon fiber or Kevlar reinforced with epoxy resin for areas of your aircraft where strength is required without adding too much weight.