Engine Cowl Split Line

SeanB · #1 09-05-2019, 01:07 PM

Hello,

I'm about to make the longitudinal/split line for the upper and lower cowl halves to match. Front ring is pretty good and have trimmed the aft lines at the firewall.

Question: Is the split line supposed to be parallel to the longerons of the cabin area? Or...just go with a line from the intakes split, then aft to a point that satisfies both sides to match?

Thank you!

WingsOnWheels · #2 09-05-2019, 01:16 PM

Do what looks nice. However, make sure you trim so that you leave enough of the cowl flange so that the hinge (or other fastener system) can be attached without interfering with the honeycomb core.

SeanB · #3 09-06-2019, 07:12 AM

Thanks, Colin. I?ll watch for spacing. It seems the top cowl is closest to the eventual cut line. Holding a straight edge on it tells me it is not flat along the long split line. Now wondering if this should be ?flat?, meaning perpendicular to the thrust line. or just clean it up and go? I understand the bottom cowl gets trimmed quite a bit.

lr172 · #4 09-06-2019, 11:39 AM

On my 10, I have VERY little extra to work with. The line goes where you can make a straight line from the material you have. If I had extra, I would possibly try to match the longeron, but don't recall how close they are on a parallel plane.

Larry

Reformed SeaSnake · #5 09-06-2019, 12:05 PM

I had a ton of excess ?glass to remove on my 8A and made the split parallel the longerons. A buddy of mine just did his 7A cowl and had very little to work with (maybe 1/4?). He pretty much just sanded the cowl halves so the split line was straight.

If you have plenty to remove AND plan to use some type of cam-lock fastener, you might give thought to placing the split line location on the firewall in a way that optimizes the cam-lock fastener flange spacing around the firewall. The Skybolt fastener plans I used reference that. Obviously,iIf you?re using hinges, that does not matter.

jibby212 · #6 09-06-2019, 02:34 PM

I just did my cowling on my rv7 and the split line was not parallel to the longerons like I figured it was going to be. Definitely not enough material to make the parallel.

SeanB · #7 09-06-2019, 02:38 PM

Thanks for the replies everyone. I don't have a bunch of excess material with the split line. Just bought a green self-leveling laser. Gonna level the plane then shoot the line. Will get agreement on both sides according to overlap and common points....then cut it! Using Skybolts and trying to get equal spacing for the intersection. Will be reasonably close, but not perfect. Oh well, it'll still look cool! Movin' on!!!

BobRV7 · #8 04-20-2020, 12:27 PM

Hey Sean, wanted to ask you about your cowl fitting, I'm trying to fit mine in my RV7 these came in my kit (Cowl,6/6A top C/S-1 ------ (Top cowl pre preg)
Cowl 6/6A bottom 0-360---- (Bottom cowl pre preg)
The bottom cowl has a 0-320 stamp on it instead of the 0-360 which is the engine I have. The 0-320 bottom which I have looks like it would fit if I trim 1/2" off the top sides of the bottom cowl from the front to the back so it will fit the top cowl is that what you had to do on yours?

BobRV7 · #9 05-23-2020, 07:45 AM

I ended up finding that the lower cowl stamped 0-320 for the 0-360 engine was the wrong one Vans sent the correct one and I'm sending the wrong one back, sure glad I didn't cut it. It was stamped for the 0-360 and if you look at both of them they are pretty much the same. Gary at Vans sent me a DWG of the difference and is measuring from the top of the scoop vertically to the bottom of the lower cowl is 4 1/2" for the 0-360 and the 0-320 is 2 1/2"

slngsht · #10 08-08-2020, 02:03 PM

I'm just doing my cowling on a 7A with IO360 cowling.

I had VERY little to trim on the aft side of top (right where the firewall bend is, there was nothing to trim but it reached), and the seam between the upper and lower cowl is short. One left side they barely reach with the slightest overlap which I can sand. On the right, there is about 3/8" gap. Not sure what's up with that.