What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Cowling Edge Distance

TCONROY

TCONROY

Well Known Member
After taking the last 2 weeks off due to my wife giving birth to our adorable little copilot, I'm back on the -7 project.
I can't seem to get the lower cowl to come up high enough on the right side. The upper cowl is trimmed and fits nicely. The lower cowl fits at the front and I have trimmed the bottom between the gear legs to fit nicely against the firewall edge. It seems like there isn't enough fiberglass in either the upper cowl edge or the lower cowl edge at the aft end (notice extra space in the picture). I've trimmed the front of the lower cowl a bit to make them fit, per the plans, but that is it. I've seen pictures here of guys that trim 1/4" or 1/2" from the sides of their cowls. I will be able to get mine to match up with just light sanding, other than the aft end. The left side will require maybe 1/8" of trimming.
Am I doing something wrong or did I get a sub-par cowl...?
My intention is to use SkyLock fasteners along the firewall and the standard hinges along the sides.

photo1.JPG
 
Once you trim the bottom aft edge of your bottom cowl, you can then raise the bottom cowl to be flush with the bottom fuselage skin. This will change the fit between the top and bottom cowl halves, and likely close up the gap that you currently have.

That is, if I'm understanding your question and the picture correctly.
 
Once you trim the bottom aft edge of your bottom cowl
Click to expand...

I have already trimmed the bottom aft edge of the lower cowl, so it can't be brought up any more to close that gap.
 
TCONROY said:
I have already trimmed the bottom aft edge of the lower cowl, so it can't be brought up any more to close that gap.
Click to expand...

I'm with Kurt. The pictures shows the bottom cowl extending over the FW flange and onto/over the side skin. Is this picture of lower cowl before trimming it? If not then it should be trimmed fwd more (aft edge) and match the upper cowl line. Upper cowl shows trimmed and sitting on the FW flange correctly.
 
Last edited:
Short cowl

Hey Trevor, congrats on the new crewmember!

I had the same issue with the pink cowl. Did a a bunch of web searching and discovered a few others with the same problem. I recall sending pictures with dimensions to Van's and they said the cowl's they had were the same size. At least I was in good company! I know that at least one builder shipped the lower cowl back to the vendor to get the sides extended. I elected to try to make it fit before going that route. Trimming the lower cowl so that it rests on the sky bolt flanges and off of the forward skin brought the cowl up enough to meet the upper cowl. Give it a shot, if it still doesn't work you can either add whatever you need using techniques outlined elsewhere on this great site or bite the bullet and ship it back to Oregon.

I'll check this evening and see if I have any pictures that you might compare yours to.
 
The pictures shows the bottom cowl extending over the FW flange and onto/over the side skin. Is this picture of lower cowl before trimming it?
Click to expand...

The lower aft portion of the cowl in-between the gear leg cutouts has been trimmed in this picture. What has not been trimmed is the aft edge from the landing gear cutouts upward along the firewall. The plans indicate to trim that last after the hinge is installed in the sides.
 
Loren said:
Hey Trevor, congrats on the new crewmember!

I had the same issue with the pink cowl. Did a a bunch of web searching and discovered a few others with the same problem. I recall sending pictures with dimensions to Van's and they said the cowl's they had were the same size. At least I was in good company! I know that at least one builder shipped the lower cowl back to the vendor to get the sides extended. I elected to try to make it fit before going that route. Trimming the lower cowl so that it rests on the sky bolt flanges and off of the forward skin brought the cowl up enough to meet the upper cowl. Give it a shot, if it still doesn't work you can either add whatever you need using techniques outlined elsewhere on this great site or bite the bullet and ship it back to Oregon.

I'll check this evening and see if I have any pictures that you might compare yours to.
Click to expand...

I don't want to rivet the upper forward skin on yet but do want to fit the SkyBolt flanges. Did you cleco them in place along the firewall and then fit/drill the cowl fasteners? I would assume there is enough play in the system that when it came to rivet the flanges, it didn't change the fastener operation?
 
TCONROY said:
I don't want to rivet the upper forward skin on yet but do want to fit the SkyBolt flanges. Did you cleco them in place along the firewall and then fit/drill the cowl fasteners?
Click to expand...
Yes. There's quite a bit for the clecos to hold together there, and they hold best if none of the materials have been dimpled or countersunk. In some cases it worked best to insert the clecos from the bottom side .. that way they weren't in the way of everything going on on top.
TCONROY said:
I would assume there is enough play in the system that when it came to rivet the flanges, it didn't change the fastener operation?
Click to expand...
Correct.

another idea ... After I riveted the fastener "receptacles" into the upper flanges and clecoed the whole works together, I located the holes in the top cowl by shining a light up thru each fastener. For my Milspec fasteners it worked great.
 
It looks like the front don't line up as well. Is that the best it ban fit at this point? It would be a shame if you cut it and then have to modify the front portion to get them lined up.

I had to fuss with them to get them line up closely but it saved me a bunch of work.
 
I have mounted all the sky-locs down the sides and bottom of the firewall. The top (where the skin attaches) sky-locs are fitted, but not installed. I don't want to install the forward skin, but with a set of fixed skybolts, the potential of miss fitting the top cowl does not excite me. I will likely just drill the center holes and use clecos to hold it in place until the skin is riveted on then finalize the cowling. I have a lot of glass work to do to accommodate the increased sweep of the Hartzell composite prop in full pitch.

The plan is - - if gaps are present, use a flox mixture to stretch the glass, sand back square and be happy.
 
Same issue 5 yrs ago

Unfortunately I had the same issue five years ago. Spoke with the manufacturer. They measured and found the same dimensions. I had to add material and additional internal glass layups.

It is a shame that Vans and the manufacturer haven't corrected this.
 
Trevor, I will try to send you some pictures via email.

I ran the Skybolts all except the one that fits at the seam and did that one last so I could make the horizontal line equal to that last skybolt. I'll get on the main computer and send you pictures
Jack
 
You must log in or register to reply here.
Back
Top