Cowl paint?

[StickandRudder]

So I really want to paint my RV (when I get it) like my grandpa's B-24 "Red ***," but I have a concern. I was reading the FAQ on another aircraft manufacturer's website the other day, and they talked about how they did not paint any of their aircraft black (all fiberglass construction) because of heat concerns. Now as you can see below, my paint scheme requires me to paint part of the cowl black. Should I be concerned about temperature problems? If so, is there any way to work around this? Planning on using a Sam James Cowl/plenum setup if that makes a difference.

Thanks!

 

[Bruce]

S&R,

Congrats on the class of 12.

I think you will have to foil the inside of the cowl.
I am running into problems with the top cowl paint.
Will have to put some real paint on it I guess.
Used AKZO primer. Looked OK but fading quick.

I have the James cowl and plenum. It builds more heat
when you shutdown on the ground.
Just my .02.

Good Luck in the future.
Boomer

 

[StickandRudder]

Hey thanks! Are you satisfied with the Sam James setup so far?

 

[StickandRudder]

Anyone else have input? Is it bad to paint your cowl black?

 

[F1Boss]

Don't lissen to Boomer

Black will be fine; the engine will 'bake it on'. Use a good primer & paint - ones that are designed as a system (same manufacturer).

Another option would be to put your kit in a big box & send it here. I'll take good care of it. DON'T send it to Boomer!

BTW I think your dedication to your Grampaw is the best thing to apply to your plane...well, rivets here and there are also a good thing to apply. Please be sure to tell everyone who will listen why you did it, lest we (they) forget. Don't be shy about this part!

Carry on
Mark

 

[DanH]

Anyone else have input? Is it bad to paint your cowl black?

Not really.

The prohibition against painting dark colors on epoxy/glass has to do with loss of structural strength. The problem revolves around a spec known as "glass transition temperature" (Tg). In simple terms, above Tg the epoxy starts acting more like a hard rubber than a firm solid. Rubbery wings are no good.

Tg varies for different epoxy systems. It's one of the items to consider when picking a product for a specific application. We don't know anything about the pre-preg epoxy used by Van's vendor to build cowls, so we can't assign a specific "don't go there" value. However, the cowl shell is mostly loaded in tension (like a balloon) so Tg shouldn't be critical. As a practical matter, engine heat pushes cowl temperatures to high levels anyway....why worry about sun heating?

 

[StickandRudder]

Black will be fine; the engine will 'bake it on'. Use a good primer & paint - ones that are designed as a system (same manufacturer).

Another option would be to put your kit in a big box & send it here. I'll take good care of it. DON'T send it to Boomer!

BTW I think your dedication to your Grampaw is the best thing to apply to your plane...well, rivets here and there are also a good thing to apply. Please be sure to tell everyone who will listen why you did it, lest we (they) forget. Don't be shy about this part!

Carry on
Mark

Thanks, appreciate it! Found out during my research that it was the lead bomber on D-day, so I can't think of a better way to paint my RV.

Tg varies for different epoxy systems. It's one of the items to consider when picking a product for a specific application. We don't know anything about the pre-preg epoxy used by Van's vendor to build cowls, so we can't assign a specific "don't go there" value. However, the cowl shell is mostly loaded in tension (like a balloon) so Tg shouldn't be critical. As a practical matter, engine heat pushes cowl temperatures to high levels anyway....why worry about sun heating?

Fair enough. I was mainly worried because of the higher temperatures already associated with the Sam James setup. I think I'll probably integrate a Stewart Warner oil cooler for good measure.

 

[Bruce]

I love this sight.Thanks Rocket .. I will be down to help because you need supervision.