This is the main issue I have when doing my scratch builds. I first try to source decent plans or drawings, just something to use as a starting point so I can use my computer drawing program to scale them to 1:32 scale (I only build in 1:32). I have given up on so many scratch builds due to a lack of plans or drawings, even good quality photos can be usefeul when doing scale drawings. I find most of my information on the net, just a matter of spending countless hours searching different sites, eventually something will crop up which will prove to be sufficient, it takes time to check link after link after link with most leading nowhere but the odd ones do show some light. I have tried to contact museums where original examples of the machines sit, but the majority of museums will not offer any type of assistance, many of them don't even answer my emails.
With my latest scratch build, the Curtiss Hydroaeroplane I was extremely fortunate to find and purchase a great book with a full history and excellent plans and drawings, this has certainly made my job a lot easier. Keeping a look-out for new publications on these early aircraft will also prove very fruitful sometimes.
Des.