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Cowl scribe lines not level

Jwputnam

Well Known Member
When i mount my upper and lower cowls, there is only about a half inch overlap of the two skins at the firewall. That makes it impossible to run a scribe line LEVEL to the nose air inlets. I am ASSUMING that this line is supposed to be level, but perhaps I am wrong? The only possible line is a good bubble off of level.

At any rate, I have seen photos of others and they seem to have far more overlap than I do.....like Don Jones photos of his SkyBolt installation and the SkyBolt illustrations as well.

This issue also forces me to alter my SkyBolt spacing considerably. I have to adjust the spacing quite different from the illustrations so as to match at the scribe line, but i can still keep the bolts spaced within the 3.5 inch suggested limit. Jeez I hope that I am not screwing this up.

Anybody else seen this problem?
 
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NOT LEVEL!!!! A nasty surprise.

When i mount my upper and lower cowls, there is only about a half inch overlap of the two skins at the firewall. That makes it impossible to run a scribe line LEVEL to the nose air inlets. I am ASSUMING that this line is supposed to be level, but perhaps I am wrong? The only possible line is a good bubble off of level.

At any rate, I have seen photos of others and they seem to have far more overlap than I do.....like Don Jones photos of his SkyBolt installation and the SkyBolt illustrations as well.

This issue also forces me to alter my SkyBolt spacing considerably. I have to adjust the spacing quite different from the illustrations so as to match at the scribe line, but i can still keep the bolts spaced within the 3.5 inch suggested limit. Jeez I hope that I am not screwing this up.

Anybody else seen this problem?

My SJ Cowl and RV7 did NOT have the upper/lower split line parallel to the longhorns, I had to de rivet and reinstall my skybolt's!!!!
 
The cowling on my -10 had about a quarter inch of possible overlap at the aft edges. That very much limited my ability to select a cowl split location. I went with the best fit and am satisfied with the result.

I think you need to start at the inlet and work aft with the best fit line wherever that lands it. The other option is to scarf additional material to either the upper or lower cowl half (or both).
 
Well, that takes a load off of my mind and saves a lot more worrying and refitting time. Gonna go with the best line I can fit.

THANKS
 
I just started install of my pink RV-4 cowl. The front halves align just fine and the back has an overlap. I will have to do some serious trimming and fitting to make all the gaps perfect. The stock cowls are not very builder friendly.
 
I just started install of my pink RV-4 cowl. The front halves align just fine and the back has an overlap. I will have to do some serious trimming and fitting to make all the gaps perfect. The stock cowls are not very builder friendly.

More overlap is better. Pick the front and back end points, connect 'em, and cut half of the cowl along the line. Use that half of the cowl to mark the other half, and cut that one. Use a long sanding block to sand to near final shape, then use a hacksaw blade to create the final gap.
 
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If I were redesigning the cowl, I would make the top longer on the sides so it is easier to get the bottom cowl off. If the top was 2" longer and bottom 2" shorter, life would be good!

I was surprised the cowl lines were not level just like everyone else. I did a Vans cowl first, didn't like it so i got the James cowl. I do like the round inlets.
 
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