The Centuri fins are a different two piece glue joint, it's longer down the root edge side. The Estes re-issue kit has a smaller triangle glued onto the upper leading edge.
TRIVIA: Many of the Centuri kits released before 1971 suggested to fill the balsa grain before gluing the fins onto the body tube.This instruction sheet is dated from 1969.
Maybe that's when I started doing it this way.
When filling the grain after assembly, I was never happy with the way the balsa looked around the root edge / fillet area.
More stuff to think about:
Some forum posts comment that the water based CWF warps balsa fins. The warp usually goes away when the other side of the fins is treated.
When filled off the model, fins treated with Sanding Sealer also warped! Dope based paints shrink and continue to shrink even after you think the sealer is dry.
In later instructions you are told to mask and paint over the clear payload section.
Many builders will paint the balsa shoulder underneath the ends of the clear tube. It makes more sense (and a better fit) to paint over the clear tube. I've always done it this way.
More TRIVIA: The 1971 catalog CLICK HERE says the Payloader II will reach 2,000 feet with a C6-5 engine.
The 1976 catalog CLICK HERE downgrades the performance stating: "Streaking as high as 1,000 feet!"
Chris, You are correct that sanding sealer does warp the fins, I leave them weighted down for 24 hours after final coat and that helps keep them flat. I don't really get any warps with sanding sealer or CWF but I will get warps from priming, go figure. I have tried CWF a couple of times but cannot get the grain filled as nice as with the sanding sealer, probably something I am doing wrong but also never had warp issue applying CWF when doing both sides.
ReplyDeleteHi David,
DeleteRegarding grain filling - you've got yo go with what works best for you. My blog is just how I do it, not the only solutions. Personally, I get better results with CWF. I only use one application of CWF as opposed to four coats of sanding sealer. Any remaining grain is filled with the primer/filler.
I think what I did wrong each time I used CWF is I sanded down to the balsa like sanding sealer hoping all that was left was filled grain. I would do 3 coats of CWF with sanding in between and still end up with grain showing. I will try again this time sanding leaving a thin layer of CWF.
ReplyDeleteHi David,
DeleteWhen you sand you should try to leave a very thin "skin" of CWF overall on the fin. The fin will not be raw balsa tan or pink but the beige color of the CWF.
Another problem I have now is with the Tung wood Estes uses in it's kits. It doesn't fill as easily as balsa. Sometimes I get to the primer spray coat and I see open grain pores! It's maddening.