Has anyone got a method of using RA microfilm over itself for trim? I'm used to Ultracoat over itself, trim monokote, etc. But RA is so thin it doesn't seem feasible to overlay a precut piece onto another sheet?

Any suggestions? I've done some masking and painting with Gordon's frisket masks but that's not a great solution either.

Pete

Pete,

I have done it many times with great results. I just use a glue stick to apply the trim. Then smooth out it with your fingers.

Joe.

How do you keep it flat Joe to cut it? Static electricity, a spritz of water on the cutting board?

Pete,

I place the film on my cutting board and cover it with wax paper. Then I use a fresh #11 blade to cut out my trim.

I've applied the second layer of trim with 3M77 and it seems to work pretty well. The insignias on my Cartoon Nieuport 17 were done this way.

Gordon

This reply is somewhat off topic, but a good hint to tuck away.

I substitute Depron for balsa when making wing ribs on some planes to effect lightness. No problem if its going to be covered with tissue, but for planes covered with RA, it's a big problem.

Therefore, I reduce the outline of the Depron ribs by 1/16 all around, then cap the ribs with strips of 1/16 balsa. Now, when covering with RA, a quick pass with the iron adheres the film without melting the foam.

Jim,
Nice technique. Do you think it would work with 1/32 balsa strips for a bit less weight? Do you punch holes in the Depron ribs to lighten them?

Gordon

Originally Posted by Gordon Johnson

Jim,
Nice technique. Do you think it would work with 1/32 balsa strips for a bit less weight? Do you punch holes in the Depron ribs to lighten them?

Gordon

Gordon, it depends on the chord thickness whether I poke holes in the Depron. Usually, the weight saved isn't worth the loss of strength.

As far as using 1/32 cap strips, I haven't tried it, but glue a strip onto a scrap of Depron and run your sealing iron quickly over it. When I applied the 1/16 strips, I found that a little less than 400 degrees F would still adequately bond the RA to the wood. (The English use of the term "timber" just popped into my mind!!). But realistically, unless you're going for really low wing loading (and you're the king, here), I'm not sure the weight saving adds up to a whole lot.

As always, YMMV !!

P.S., my current project is to make a 16" wingspan mostly-scale rendition of the Chance Vought V-173 "Flying Pancake", using mostly Depron, along with judicious use of Balsa for spars and rib cap strips and a leetle-bit of carbon. I will use this method of RA over Depron to the max. Just for nostalgic sense - and strength - I plan to laminate the whole outline from several strips of soaked balsa.

I have blown up a very scale-like Peanut scale plan. I'm thinking of using two 4000 Kv AP03's turning scale-modified GWS 5x3 three bladed counter-rotating props, driven by a DelTang Rx with twin-steering. Geting the CG at about 18-20% is going to be a challenge here, as I always hate to use bigger than necessary LiPo cells just to balance!!

Very cool Jim. Can you post your plans as you work out the details?

Originally Posted by Petefoss

Very cool Jim. Can you post your plans as you work out the details?

I certainly will right after Easter, I plan to get back to my drawing board and sketch some equipment placement and control setups to get the CG close right off the bat.