Scale Aircraft

[71Eagle]

Why are replica aircraft normally not built to 100% scale, it seems like they are usually 3/4 or 7/8ths.

[RobW]

Primarily cost. Secondly, size and storage.

Arguably, the most difficult part of building a replica is obtaining an appropriate engine. Once you scale the aircraft down a little, your engine choices open up considerably, and since they are smaller engines, they are significantly cheaper.

Regarding size considerations... Take the Fokker D.VII... it is over 9 feet tall... which makes it a challenge to fit into many hangars. Scale it down a little, pull the wings off, and you can store it in your garage.

[Leatherhead]

I think the number one reason is do to engine choice. A full-scale WWI aircraft requiring a Mercedes or BMW engine (i.e. D.VII) is going to create a real problem in that the engine is nearly impossible to find or is cost prohibitive. Some are inverting GQs and others, but it's a real challenge. Likewise for a WWI aircraft that was originally equipped with a rotary, finding a Le Rhone, Clerget, etc will be a challenge. A scaled down version, which will weigh less, can easily use alternative engines (i.e. VW and others). Material cost will be less, but not hugely so.

[Joe Perkel]

Originally Posted by RobW

Arguably, the most difficult part of building a replica is obtaining an appropriate engine.

This statement is so true as to be profoundly so! In fact, unless going for museum accuracy,... airframe plans be dammed, just shape an existing design(s) into what you want Frankenstein style and voila!

But the engine and it's original performance specifications, now that's a head scratcher! So much so in fact, I gave up on worrying about it to adopt the "If you build it, it will come" philosophy.