I've encountered numerous references about thinning trailing edges on scale model aircraft, but have yet to find any definitive information or book references on how to determine whether a wing is, in fact, too thick, or how to go about correcting one. I model World War II aircraft primarily. Can any of you experts out there in Armorama-land offer any tips and/advice on these two related issues, or point me to a web site or book reference that provides instruction.

Thank you in advance for your guidance.

ZONER1- I don't know how far you want to go to reproduce the trailing edge. Yes they are very thin, to the point of looking fragile (and they are). Having worked around aircraft, several years at McDonnell Douglas and now volunteering at an Air Museum, I can tell you from personal experience they are SHAPE. If you bump into one it can lay you open, but they do very from aircraft to aircraft. Even leading edges are shape on fast flyers like the F-104. I don't know of any documentation that can help you other than design doc's for the wing. In any scale if they look like a knife blade you're close.

Hi Zoner 1

I'm all with CRS on this... my principle is " as thin as possible..."

It's probably fair to say EVERY kit can do with its trailing edges thinning down.... some of them scale up to being several inches thick...

Hope this helps

Rowan

Your question is in the 'how long is a piece of string' category.

Aircraft that are of all metal construction can be roughly divided into two categories. Up to 1945 and after 1945. Until aircraft approached high subsonic speeds flying surfaces were of so-called conventional construction. This is a metal form of the balsa flying model. The ribs that formed the aerofoil shape terminated at the trailing edge with a U section formed from sheet or an extrusion, to which the upper and lower skins were rivetted. As the airflow aft of 33% chord is fairly irrelevent to the performance of a low subsonic aerofoil there was no need to bother too much about making the trailing edge especially thin. Add to this the need for the trailing edge to be able to withstand impact with ground equipment (I once drove a Clark tractor into the trailing edge of a DC-3 with no damage to anything except my pride) then you can appreciate designers did not bother with refinement.

As speed reached high subsonic and compressibility effects were encountered there was a need to reduce aerofoil thickness and take an interest in the shape of the trailing edge.

With thinner aerofoils came new construction techniques. Extruded, honeycomb and milled sections were employed. With these materials a razor sharp trailing (and leading) edge became possible.

Of course in the case of a model just about any as-moulded aerofoil trailing edge is going to be too thick. However, sanding super sharp edges on older, slow speed aircraft is probably a waste of effort. You also have to consider how much damage your sanding will do to surrounding panel/rivet detail.

Bet you wished you hadnt asked!

Regards Dave

:-) ZONER1, first let me welcome you to Armorama
I build WW II aircraft and have only thined 2 or 3 trailing edges, only because they were realy thick.
It is quite easy to do but can cause a few problems. To thin the trailing edges simply scrape withe a hobby knife or scalpel, to remove most of the unwanted plastic, then sand to finish off. If you are not careful though all you will suceed in doing is to create an opening in the trailing edge. This is because the wing halves are touching further into th wing, so you have to remove plastic further back. Just test fit as you go. One other problem you might create is that the wing is now thinner than the wing root, so that might require sanding as well. HTH :-)
Mal
EDIT: I am talking about thinning from the internal side.