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Designing (and hopefully building) the Cheap Air Racer.

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nerobro

Well-Known Member
Joined
Nov 6, 2011
Messages
1,128
Location
Northern Illinois
Lets start at the begining: https://www.homebuiltairplanes.com/...-cheap-air-racing-class-promote-aviation.html

The concept I took from that thread, is that we need a cheap way to go air racing, so we can get air racing done more often, and in more places. People seeing planes do their things, with normal people at the controls, should get more people wanting to fly, and hopefully help re-invigorate the sport.

Lots of ideas were tossed around. Lots, and lots, of ideas. Ranging from getting Formula Vee going again, to "lets make a class for Cessnas."

And my mind's gears started turning. I came up with a concept for a Cheap Air Racer. I thought it needed to be a very fast build. I thought it needed to be ridiculously strong. To be practical, everything had to be available new, which means a current production engine. And it needed to be cheap enough that someone with "expensive" hobbies could do it.

I chose wood as the material, as that's the least common denominator when it comes to construction tools. Metal tools work wood pretty well. Composites people tend to have saws and such. And wood people are already ready.

The engine I first looked at, was a B&S 25hp. 5hp is enough to fly, but not well. I did a little math, with the help of Raymer, and did my first few revisions.

I ended up with this as my first "hey what do you think of this?" design.

CheapAirRacer_01.jpg


500 lbs MTOW
200 lbs Pilot
25 HP B&S on the front
48 kts stall
140 kts design top speed

Now that's just a drawing. The numbers have some basis in reality, but the design is just "well that seems about right to me" at that point.

Topaz suggested that I share how I came up with that design, and show how I'll prove if it's viable or not.

In the next post: Revision history, and changes to the design.

Future posts:
can the wings take it? Making wing shape choices and spar design.
Is the fuselage to heavy?
Why 25hp? And other firewall forward decisions.

And there's going to be a lot of posts of just drawings.. showing the bits as I develop them. And showing the math behind those parts.

Do you have questions? Suggestions? Think I'm crazy? https://www.homebuiltairplanes.com/...p-air-racer-discussion-thread.html#post234758
 
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