Oil door in cowl bowing in flight

[rvbuilder2002]

I'm pretty sure the RV-10 plans specify that a piece of 1/8" thick foam core material (supplied in the kit) with the edges scarfed, be bonded to the inside surface of the door and then a layer of glass cloth epoxied over it.

Makes the door as stiff as an .063 aluminum one.

[Kyle Boatright]

Originally Posted by rvbuilder2002

I'm pretty sure the RV-10 plans specify that a piece of 1/8" thick foam core material (supplied in the kit) with the edges scarfed, be bonded to the inside surface of the door and then a layer of glass cloth epoxied over it.

Makes the door as stiff as an .063 aluminum one.

Yep. It is extremely stiff when built to plans. I can't imagine it bowing in flight.

[BillL]

Originally Posted by JackinMichigan

The access door on top of the cowl has a significant bow to it while in flight. I've made the habit of taping it down with military grade duct tape, but that won't be an option once I get it painted. I feel as though I need to stiffen this door somehow. It's contoured to the cowl, so a simple fat bar stiffener won't work here. Anybody got any ideas?

Being a builder I assume you have some epoxy. Email your address and I will send a patch of 3mm Soric - it is expensive to buy a small portion and I have scrap that big. Trust me - if the door is flimsy and the hinge is not part of the problem, this will stiffen the part and it is light too. Easy to do, really easy. One layer of glass and use peel ply or preload the glass so it is minimal thickness.

Do have some glass left over too?

Bill

[Carl Froehlich]

Originally Posted by rvbuilder2002

I'm pretty sure the RV-10 plans specify that a piece of 1/8" thick foam core material (supplied in the kit) with the edges scarfed, be bonded to the inside surface of the door and then a layer of glass cloth epoxied over it.

Makes the door as stiff as an .063 aluminum one.

Please provide the part number.
Thanks,
Carl

[Kyle Boatright]

Originally Posted by Carl Froehlich

Please provide the part number.
Thanks,
Carl

It is called out as " cowl-10-01B" on page 47-10 of the RV-10 plans.

[rocketman1988]

I ended up trying the foam core on a test piece and compared it to a test piece using SORIC.

The SORIC piece was MUCH more rigid than the piece using the foam core...

Just a data point...

[CharlieWaffles]

Is the bowing along one of the edges or truly in the center of the door? I have a very stiff door, but I experience a slight bowing at the rear corner on the same side as my latch. Since my latch is in the center of the door edge, the aft end is bowing on my due to the high pressure in the upper cowl. If I had it to do again, I would have installed two latches, each near the corner to mitigate this issue.

[lr172]

Originally Posted by wjb

No flight test yet, but I'm following the recommendation from elsewhere on the site to save the cut out piece of the cowling and bond it to the bottom of the oil door. This extra piece of glass should significantly stiffen the structure (stiffness goes up with the cube of the thickness; should be at least 8 times stiffer!)

+1

I did this on the 6 and it makes a very stiff door that won't bow.

Larry

[lr172]

Originally Posted by Kyle Boatright

It is called out as " cowl-10-01B" on page 47-10 of the RV-10 plans.

That's interesting. I don't remember seeing this in the finishing kit.

Larry

[rvbuilder2002]

Originally Posted by rocketman1988

I ended up trying the foam core on a test piece and compared it to a test piece using SORIC.

The SORIC piece was MUCH more rigid than the piece using the foam core...

Just a data point...

I guess there is nothing wrong with much more rigid, but in the context of RV kit engineering, just rigid enough is best (especially when it means using an inexpensive piece of foam that takes no additional effort to obtain.

The RV-10 prototype has 2000+ hrs now and its oil door was made exactly as shown in the plans. It does not bow up in flight from plenum pressure.