Cowl Symmetry

I was looking at my cowl today and noticed that the angle of the scoop opening and the front of the cowl are off. I laid levels on the front and over the scoop, it seems neither is square with the fuselage. I am pretty sure the front of the cowl should have this angle as the engine is mounted offset and the top and bottom section of the cowl seem to have the same angle. I could not find anything in the plans that tells you the cowl will fit like this, all of the drawings for the cowling show everything parallel and square and very symmetric.

The scoop seems to have been glassed in later and I am not sure the opening in the scoop should have this angle. I wonder what you others have found, should the scoop be centered and square here or is there a purpose to the angle. Trying to decide if I have a defective cowl.

Thanks for any help

Cheers

I'm assuming you haven't trimmed your cowl yet. They come very roughly trimmed and setting them on edge like that doesn't tell you much until trimmed to square with the fuselage. There is lot of excess material to work with at the aft end of the cowl, so getting it trimmed to fit should not be a problem.

If in doubt, you can always ask the Mother Ship!

Mark Olson RV-7A F1-EVO Rocket

trim does not matter

molson309 said:

I'm assuming you haven't trimmed your cowl yet. They come very roughly trimmed and setting them on edge like that doesn't tell you much until trimmed to square with the fuselage. There is lot of excess material to work with at the aft end of the cowl, so getting it trimmed to fit should not be a problem.

If in doubt, you can always ask the Mother Ship!

Mark Olson RV-7A F1-EVO Rocket

Click to expand...

I know it will get trimmed at the fire wall end but these angles relative to the sides are not square. I don't think trimming the aft end to match the firewall will straighten the difference between these angles.

I know I can ask the mothership but answers VIA this forum is more timely in many instances, thanks for the suggestion though.

The engine is not strait on the firewall so the the prop backplate will be at an angle but the air coming in the scoop will flow heads on.

RVG8tor said:

...Trying to decide if I have a defective cowl...

Click to expand...

I'd bet that if you get a replacement, it won't be much different. As others point out, the RV-8 engine mount cants the engine to the right a degree or two, and the cowl is shaped to accommodate that asymmetry.

I don't think that there is any impact other than perhaps aesthetic. In your place, I'd revisit the scoop once the cowl was trimmed and fitted, and maybe dress it a bit with some microballoons and fine glass. Or maybe not.

Thanks, Bob K.

Thanks

From the sound of the inputs, it look like there is nothing wrong with my cowl, it just seemed odd that the scoop opening did not appear to be square with the front of the plane.

Of course I have to finish the skirt and windscreen before I get to the cowl, I am finding this glass work somewhat intimidating but I am educating myself and feeling better about it each day, it is just slowing me down. More than you all wanted to know I am sure!

Cheers

Mike,
I am in the last stages of my cowl work.
I highly recommend a review of DanH's threads on cowl work. Especially the part about putting the two halves together at the nose area. It makes for a good starting point.

Don't be timid with MAKING the parts fit the way you want. Heat, force, trim, buildup with flox etc.

I see the nose angle in your image. I imagine it is mostly due to the engine angle others have stated. Mine had little error in this direction compared to engine although I never checked it like you did prior to mounting on the airframe. However, mine had distortion in other directions that had to be doctored. (Kind of sunken in at the seam lines which is common I understand). Trudge ahead and get used to being covered in white powdery fiberglass sanding residue