Cowl Fitting

[paul330]

I am fitting the engine cowl. I temporarily fitted the prop, measured everything up and made a plywood disk to simulate the back of the spinner - so far, so good.

However, from what I can see, there is no support for the cowl forward of the firewall. This seems to mean that you have to ensure the front of the cowl is VERY accurately taped to the wood disk so that the rear hinges hold it in the correct position. Even having done that, the cowl doesn't have any internal bracing and the whole thing looks a bit "wobbly".

It seems almost inevitable that I am going to end up with cowl droop - or am I missing something?

Incidentally, I am using the stock hinge fitting.

 

[rleffler]

I am fitting the engine cowl. I temporarily fitted the prop, measured everything up and made a plywood disk to simulate the back of the spinner - so far, so good.

However, from what I can see, there is no support for the cowl forward of the firewall. This seems to mean that you have to ensure the front of the cowl is VERY accurately taped to the wood disk so that the rear hinges hold it in the correct position. Even having done that, the cowl doesn't have any internal bracing and the whole thing looks a bit "wobbly".

It seems almost inevitable that I am going to end up with cowl droop - or am I missing something?

Incidentally, I am using the stock hinge fitting.

Your perception is accurate.

I aligned the spinner about 1/8" high in anticipation of the mounts being compressed and the engine dropping over the next year.

I would also recommend using a 1/4" spacer at the hub instead of 1/8". I didn't realize that I had some torque on the top cowl until after I had the aft edge trimmed. When I took the space out,the fiberglass popped back to its normal position and I lost my gap. Since I already trimmed the aft hinge line, it Ito spend significant time reworking the front of the cowl.

Bob

 

[philb]

plywood spacer works great: I drilled holes in the lower cowl front and bolted it to the plywood spacer so it absolutely did not move. Was great for trimming, provided solid base for placing/fitting the upper cowl.

Phil
SLC
-10, finishing....

 

[flion]

However, when you get both cowl halves in place, it becomes a lot more stable. The cowl halves brace and support each other.

 

[paul330]

Thanks for the tips. I particularly like the idea of fixing the lower cowl to the plywood spinner disk.

 

[pierre smith]

A better way.

Paul, from my experience, use camloks on the upper rear cowl and three on either side of the lower cowl bottom sides. Only use the hinges along the cowl seams and vertically on the lower cowl.

Camloks with 4" spacing work very well and much better than the curved upper hinges.

Best,

 

[Wayne Gillispie]

Per plans you end up replacing larger alum pins with smaller ss pins at top rear after trimming. Then your gap gets bigger at top rear joint and fwd end of cowl lowers 3/32". Plan for this as I did not!

I built mine with 1/8" spinner-cowl gap per plans and wished I had 1/4"! Right on Bob.