Cooling spit engine
 

Hi Guys,

What do you think about this plan of cooling my engine… I have a 3W muffler inside my fuse. I want to make an epoxy tunnel that leads air from the engine compartment through the tunnel. Hot air will leave through the radiators in the wing (I already made tunnels in the wing) and from the fin and tail wheel of the plane.
I hope the radiators have some kind of ‘venturi-effect’ and will suck the hot air out of the fuse.
Air will enter through the chin scoop...?

Do you think this will work…?
Any experience/help is apprieciated.

RE: Cooling spit engine
 

seems pretty complicated to me. I cool my Spit by putting a "flapper" door on the lower cowl and it opens when the propwash hits it....air is baffled over the engine cylinder and exits at the bottom of the firewall where the exhaust pipes dump the exhaust. I opened up the scale exhaust to provide additional venting of heat

RE: Cooling spit engine
 

Also seems like a pretty good idea!
Does that provide enough cooling??

RE: Cooling spit engine
 

yep...

RE: Cooling spit engine
 

Might want to make it a tropical version with lower cowl scoop. My hurricane with RCV will have this scoop.

RE: Cooling spit engine
 

Looks like you have some air going in the wrong direction? If you have too much resistance to the air flow you'll create back pressure and the air won't move well. I bring in the air in the lower cowl front and then exit it out the Oil cooler in the wing. The fuse has a small box to direct the air out. It works well and is simple and straight forward..

RE: Cooling spit engine
 

Hi BobH!

That's also the plan on my spit. Only thing is I wanted to try it first without opening the lower cowl and just using the chin scoop. If that doens't provide enough cooling, I'm also going to make small cutouts in the lower cowl. It should be okay than...

Thanks for all imputs!

RE: Cooling spit engine
 

That all sounds rather complicated to me but then I guess I`m ather simple. Here`s a couple of pictures of the front end of my 80" sport scale Spitfire showing the cooling inlet. That`s an OS 1.08 hiding behind there.

I have a custom-built muffler on one side of the cylinder head and a bent piece of ali. sheet closely following the contour of the head on the other side, and another angled piece screwed to the firewall that shoots the air down to the exit at the bottom rear of the cowling.

I was flying this model in air temperature of 31*C at a warbirds rally here just this last weekend and it never missed a beat or suggested any hint of overheating.

Alan W

RE: Cooling spit engine
 

Hi!

Looks like I'm doing it the complicated way indeed...
Oh well, somebody has gotta do it ;0)

I just would be pretty satisfied if I could cool this thing without opening up the cowl. Although I'm pretty sure I end up cutting it up anyway....

RE: Cooling spit engine
 

I have a 1/7th TF spit with an RCV 90SP under construction, and I'm looking for ways of minimizing the openings needed. I at one time considered making some scale exhausts but there is just too little room at this scale to make it practical. Now I will be opening the exhaust pipe ends to add more venting. Looks like I'll end up with a hole similar to AlfaWiskey's with a baffle to direct the air over the cylinder.

I look forward to more posts!

Scott

RE: Cooling spit engine
 

Nothing is better than putting the head right out in the breeze. In 2 years I have yet to have anyone notice the ducts on the bottom of the Spychalla Spitfires. Nobody ever gets down low enough to see it. You would have to get down on your knees to see it from the front and nobody ever does.

Leo

RE: Cooling spit engine
 

FiberClassics Spit ... How I cool Q 100 .....


The Q 100 is cooled by ducting air from the radiators under the wings, through a duct in the fuse, and into one side of the cowl. The cowl is itself ducted to only let the incoming air go over the cylinder head. Exits out the bottom.

Custom muffler mount made so no engine parts or muffler hanging out. LOTS of work, but fun to engineer it. This slowed the build down considerably !

So, air goes through the fins and out the bottom. 1/2 of the chin scoop also feeds air into the "cool" side of the cowl. Worked OK, but engine would load up after 5 minutes in the air. Seems the air in the cowl got too hot and made the carb go rich.

I added a small hinged "blow in" door on the very front of the cowl to let air directly in by the carb. That fixed the problem! Runs great now. On hot days.. I just keep it wide open and moving until it's time to land.

To help keep the engine a bit cooler I run a 24 x 10 3 blade prop. Keeps the RPM down a bit and flies the plane great. An added bonus is the 3 blade looks cool too... and pilots are always surprised whh
when I leave it on and start the engine.

Look at these pics my buddy shot last year. Look close at underside shot... you'll see the cut out on the lower cowl to let air out. You can also see the small blow in door open to let carb air in.

RE: Cooling spit engine
 

That´s a very cool looking spit!
I like how you engineerd the cooling of the engine! And that´s also part of the hobby I think....

RE: Cooling spit engine
 

[&:]

How? that is in the previous post.

Really, it's just a matter of thinking it through, making a plan, then executing it. FiberClassics shows a tuned pipe in the fuse... I just modified some things to cool the engine.

Some risk, wasn't sure it would work, but figured if it didn't, I could always add some holes in the cowl.

Good Day.