cowl gap at inlet

[Paul Eastham]

Hi,
I have just mounted my lower cowl which mates pretty nicely behind the spinner itself. Unfortunately, at the outboard ends of the inlets, there is a significant "overbite", perhaps nearly 1/8".

Have others encountered this, and how did you resolve? Solutions coming to my mind include fiberglassing over the entire area or forcing the halves into alignment when drilling the joining hinge. Neither of these are giving me a warm fuzzy feeling.

Thanks,
Paul

(looks a bit worse than it actually is in this zoomed-in photo:

[Kyle Boatright]

It looks like there is a bit of a lip on your upper cowl. I'd trim or sand that off, then build up the bottom cowl to match the upper cowl.

My cowl required a similar amount of massaging to make it fit properly.

Using the hinges to force the halves together is not a good idea. Misaligned hinges make it hard to insert the pins. Also,, pre-stressing the hinges is a good way to accelerate the wear and breakage on the hinge eyes.

[kevinh]

Yep - I used a flox/micro mixture with a bit of fiberglass layed up to fix that bad fitting spot.

It seems like Van's really should remake those two molds.

[rv72004]

Same here, built up the lower and upper then sanded for a smooth fit.

BTW this was only done after the hinges were done .

[tin man]

Or, apply even heat from a hair dryer and gently message to desired position.
Tom
northern california

[RV_7A]

Paul,

I found that shaping the areas that overlap nice and smooth will aid in these outboard corners lining up. I had to sand mine way back and add glass to the backside of cowling to get them to line up properly. Another local fellow had a much better idea and cut his tabs completely off, and laid up new ones with the cowling perfectly matched. Its very easy to do instead of trying to get a perfect fit by sanding and trimming. Even after almost sanding mine off and laying up glass on the backside it made this area much stronger where the plate nuts will be riveted.

[Rene Bubberman]

Hi Paul,

This is quite normal. I filled up the area and reshaped it. It took some time, sweat and patience, but in the end it was very nice. I have a description on http://websites.expercraft.com/PHVII...ry&log_id=9951

[casper]

Originally Posted by tin man

Or, apply even heat from a hair dryer and gently message to desired position.
Tom
northern california

Is this a theroy or actual experience. I tried heat on my cowling and it did not work

[sf3543]

Based on my experience, if you use a heat gun to reshape, it will work, but it will also tend to return to it's original shape when it gets reheated, as in flight when your engine gets hot.
You can overcome this tendency; however, by heating and shaping and then laying on some underlying layers of epoxy and cloth to hold it there, since the new layups will have the correct memory and will hold the others in place.
Then you could add what ever you need on the outside or grind it down if it's too high.
Works for me.

[Paul Eastham]

Thanks for all the replies! They gave me a lot of good ideas for this problem and all the other problemsI am having on the cowl

What worked for this particular problem: I needed to remove a lot more built-up glass from inside the overlapped area behind the spinner. I did a combination of sanding the "tongue" (and it will need some reinforcement with more glass behind later), and grinding down the area that the tongue presses up against.

I had it nearly flush when I originally posted, but the geometry of the parts seems to be surprisingly sensitive to the mating in that area.

Everything seems to line up in front now, but the aft area is another matter...still hacking away at it...

Paul