Cowl blisters/bumps source

[Norm G]

I'm going to be using long shielded plugs, AC SR-88 in my 1941 BC12. By using long plugs means cowl bumps. I know a lot of you will say how can you do that to that nice old bird and ruin the cowl. Well I've given it a lot of thought and I'm going to cut the cowl and install bumps if I can find some. That's the problem, I can't find a source for them. I know that they wouldn't be difficult to make but I don't have dimensions. So I'm looking for a source for the parts or if I can't find a set I'll need the help with the dimensions.
Thanks,
Norm G

[Hank Jarrett]

Re: Cowl blisters/bumps source

I have them on my 41 and am putting short plugs in the top to get rid of the bumps. Wish my old cowl was something good enough to trade. ;-) I have blown plastic bumps that were pop riveted in the metal and look awful but the dimensions are pretty good. I also think I have an old cowl with bumps on them but will need to look at them and take some pictures. If any of them are equal condition to your uncut cowl top it would be a lot better to save the uncut cowl and put on one already modified. I will get some photos this week and get some measurements. Can you post photos of yours to make sure I have the same hinges?

Hank

[Norm G]

Re: Cowl blisters/bumps source

Hank,
I have a extra cowl that is uncut in fair condition that I would trade in a heartbeat for a cowl with the bumps. I'll also take some pictures.
Thanks,
Norm

[Hank Jarrett]

Re: Cowl blisters/bumps source

The big difference between most of them seems to be the hinges. A LOT of guys put piano hinges on them that screwed up the attach and spacing. I need to look at what I have, but I am pretty sure several have the original type, but I would als bet they need "tweaking" to get them to work smooth. I will post photos of what I have later this week.

Hank

[astjp2]

Re: Cowl blisters/bumps source

You can get the Ercoupe bumps from univair, they are metal and the right size. Tim

http://www.univair.com/ercoupe/view-all/415-40428-ercoupe-spark-plug-fairing/

or

http://www.univair.com/mooney-m-10/view-all/f40253-m-10-spark-plug-fairing/

[TimHicks]

Re: Cowl blisters/bumps source

For what it's worth, when my plastic cowl bumps were breaking up, I bought a pair of the long, shallow aluminum Ercoupe bumps from Univair.
I liked the idea of aluminum.
But they weren't deep enough.
Even though I really wanted them to work, I couldn't find any way.
So I returned them to Univair and bought fiberglass bumps from somebody on this Forum (I can't remember from whom).
The fiberglass ones fit fine in all dimensions.

[Norm G]

Re: Cowl blisters/bumps source

Hank.
Attached pictures are the new cowl that I'll be using and the old one that I don't need.
Norm

[astjp2]

Re: Cowl blisters/bumps source

REM37BY plugs are about 1/2" shorter than a standard REM40E plug and will help with clearance. Tim