[Stewie]

Just curious if anyone out there has fab'd their own cowl cheek extensions from aluminum? I'm aware that is how they were originally supplied, but the factory no longer carries them in lieu of the fiberglass ones. Interested in obtaining or making a pair if anyone has plans.
Want aluminum as my plane is polished, thought the polished RV3 at Reno with AL cheeks looked pretty nice.
Cheers,
Eric

 

[danbenua]

I fabricated AL cheeks for my RV-3B because the factory supplied
parts did not fit. I didn't use plans, but rather followed the RV-3
builder's mantra of "make it oversize, then trim to fit".

Start by fitting your cowl and then developing bulkheads for the
forward end of the cheeks. The shape of the bulkheads is determined
by the shape of the cowling where it bulges out from the firewall
sides. Your goal in shaping the bulkheads (from .025 stock) is to
make tab'ed flanges that will support the cheek skin to exactly
align with the glass cowling bulges.

Next draw lines on your fuselage sides to define the upper and
lower edges of the cheek. You want to make the tapered cheek
look like a natural extension of the lines of the cowling, and
hopefully symmetric on both sides of the fuse.

I fabricated the cheek "cone" portion out of .020 stock. Get a
couple of extra sheets to account for re-do's. Careful measurements
of the length of the cheek top and bottom edge lines on the fuse
and the circumference of the forward bulkheads give you approximate
measurements for the triangle shape you need to cut from the sheet
stock. Again, make the cone a few inches longer than you think it
needs to be so you can trim it to length later.

I formed the cone section by using wood boards (battens) clamped
to the long edges of the triangle piece. Bend up a 5/8" flange
about 20 - 30 degrees on each long edge of the triangle.
The "cone" shape is created by pushing the two edges together
forcing the forward edge to bow upward. This step takes some
finese .

Finally the cone can be placed on the fuselage and the forward
edge trimmed to fit the cowl aft edge. From that point, drilling
and riveting is standard.

If I can find any photos of my cheeks, I'll post them to this thread
later. This may sound difficult, but mine came out light and
pretty good looking. The materials are quite inexpensive so
there is no reason not to give it a try.

Good luck!

- Dan Benua
Repeat offender

 

[Ironflight]

Listen to Dan - his cowl cheek extensions are award winning!!

We took the easy way out and made our own fiberglass ones....

 

[danbenua]

RV-3 Aluminum cowl cheek photos

Here are a few photos.
1) The completed cowl and cheek:

2) Forward bulkhead of the cheek extension. Tabs and nutplates accept
screws that secure the cowling. Also note the bracket that anchors the
end of the hinge pin that joins the upper and lower cowls:

3) Detail of upper edge of the cheek extension (and the avionics shelf!):

4) Inside view showing doublers (0.63) that protect pilot's hand from
the rivet shop heads near throttle quadrant. These doublers are
countersunk on both sides:

 

[Stewie]

Thanks!

Excellent write up and pictures Dan! I appreciate your input. I'll try making a set and if I come up with any further suggestions to add I'll post them here. Again, many thanks.
Eric