[rockwoodrv9]

I have just finished fitting the top cowling to the firewall. It is perfect! I started thinking about the bottom and wondered if I need to make sure the joint line between the bottom and top needs to be absoultly level.

In the pictures you can see where the level line - the thrust line, is. There is no way I can make the hinge line between the top and bottom level with that line. I can't make it level at all without adding fiberglass to the top cowl piece.

Is this normal or is the nose of the cowl dropping to low? I looked at about 100 paint job photos and I still can't tell if it is the same or level.

Any thoughts?

 

[Vlad]

Rocky it's been a while I did my cowling but I remember I was struggling as well. Here is what I found in my archives.

I had bunch of websites bookmarked when I was working on it. If I find those links I will post here.

 

[Vlad]

Excellent visuals here Rocky http://www.jeffsrv-7a.com/Canopy.htm


http://www.rv7-a.com/cowling.htm



http://www.flightinnovations.com/fwf.html

 

[LifeofReiley]

Hi Rock,

Keep all the length you can and fit the spinner to the cowl and gap it. Then mark and fit intakes areas. After these areas are very close, you can start marking for trimming taking small cuts. It will come together pretty quick. Focusing to much on thrust line can lead to a very poor spinner fit. A dime makes a good paint gap.

 

[rockwoodrv9]

Thanks Buddy, those are some great pictures on those sites. I think I am ok after looking at the other cowls. Thanks again, talk later, rocky

 

[rockwoodrv9]

Hi Rock,

Keep all the length you can and fit the spinner to the cowl and gap it. Then mark and fit intakes areas. After these areas are very close, you can start marking for trimming taking small cuts. It will come together pretty quick. Focusing to much on thrust line can lead to a very poor spinner fit.

I agree - I was too concerned about the thrust line. On the PDF from vans, it lines up. In real life - it doesn't! I would much rather have a nice fit around the prop than be level with the thrust line. Thanks for the help.

 

[PeteP]

Cowl fit

I am at the same point as you, fitting the bottom cowl that is. There is no way the junction of the top and bottom cowl will match the thrust line on my airplane. Make the spinner and cowl lines match and get a nice square fitting between the top and bottom is all that is possible for me. Others may get different mileage but this is what I find on my 9A.

 

[bruceh]

I'm about 90% done with the cowl fitting. Get it to fit at the front and work your way back. Draw a line on top and bottom pieces where they overlap, and try to bisect that area so you get an even amount of top and bottom for the hinges. The newer pink cowl was cut really well on the top cowling, but there was plenty of overlap on the bottom piece. It is a very iterative process (tedious) and you will be putting them on and off a million times.

There is a great write up here by Brantel on how to fit the cowling.

 

[RViter]

In the pictures you can see where the level line - the thrust line, is. There is no way I can make the hinge line between the top and bottom level with that line. I can't make it level at all without adding fiberglass to the top cowl piece.

...
Is this normal or is the nose of the cowl dropping to low? I looked at about 100 paint job photos and I still can't tell if it is the same or level.

Any thoughts?

None of the pictures, discussion or questions address one issue that I'd like to pose for your consideration. (I'm working on an RV-6A cowl now, BTW.)

The line that 'seems' to be established (and not clear to me) is whether the demarcation between the top/bottom is exactly the same on the 'sides' as in the spinner area? In other words, the side of the cowl COULD align/join on a slightly different reference than the overlap behind the spinner. The two "lines" or alignments could be different. The spinner overlap joint is one alignment but the sides of the top/bottom could be elevated and therefore adjusted/tilted to achieve a better thrust line to cowl alignment. I suspect that many of us drew a straight line across the spinner area and marked the sides of the inlets exactly the same as the overlap joint at the spinner. There is nothing that demands this alignment. The only consistency should/could be the left and right sides of the cowl at equal levels.

I found that the inlets would mate better on the outboard joint by removing more material from the top cowl than the bottom, and then using that joint line as the 'front' reference to split the sides. It appears in many photos that builders often work on the top cowl, straighten the sides (edges) and then remove the overlapping material almost completely from bottom cowl (possibly with the intent that the spinner joint and side joint must ALL align.) Flexibility is there to the builder who ignores the artificial constraint on this one. IMHO