Todd Jackson

My Feedback: (6)

Been flying the Hellcat with the RCS 150 for 4 flights now and doing great. Good power and sound but wanted to fly with the cowl yesterday. With the cowl on it seemed to get rich on takeoff roll so I aborted it. We took off the cowl and it was better. Just wondering if any one has had cowl issues with there’s and I was thinking of opening up the cowl vents more and do I need an air outlet at the bottom. Will try to get pics of the setup tonight.

Thanks Todd

fancman

My Feedback: (16)

With what that engine costs, I would not hesitate to open up whatever is needed to keep it cool. Don't need any other opinion to do that.

Todd Jackson

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I agree but just trying not to have to cut up the cowl to much if I don't have to..Thanks Todd

ww2birds

My Feedback: (14)

Todd,

Sounds like a great setup! what prop are you using? Any problems with the length of the motor or the weight? Just curious .. I have two of the RCS250s, and wondered how the 150 would do in the Z-planes...

For cooling on my 250, I used a setup recommended by Mike Dooley at RCS .. "pie slices" of lite-ply glassed in between the cylinders to force all airflow through the fins. Need a pretty close fit (1/16 to 1/8 inch) to get it to work. I just got, but have not flown with, the multi-cylinder temp monitor that RCS will be selling, this should be a great way to keep these beautiful motors running cool...

I followed the scheme that was used by Bruno on O'Meara's Sea Fury .. I'll attach a pic from his posts.

Dave

(edit for spelling!)

warks62

My Feedback: (140)

Just a thought but could it of been that the carb adjustments will need to be different with the cowl on? It wouldn't be the first time that it is different between cowl on or off.

Todd Jackson

My Feedback: (6)

That is what we were going to try next, but did not know if I needed more air getting out of the cowl because the Hellcat cowling vents are very close to the fuse. Thanks for everyone's help so far. Will post pics as soon as possible.
As far as engine length in cowl, it was fine and had to add 9 lbs. to the nose of the Hellcat to balance. Thanks Todd

The Ghost

Rebuild the cowl with the vents in the open position, should give you more airflow.

Cheers

langerl

My Feedback: (5)

Yipes!
Do you mean you had to ADD 9 POUNDS to the Z Cat AFTER mounting the RCS 150 to get a good CG!!?? I'm right at deciding what engine to add to my Cat and I'm just at the edge of considering the RCS 150. I assume the 150 is not enough to turn a scale (~29" 3-blader) for the Cat, so a conventional opposed twin looked like the best solution if you're stuck with a 26-10 or so 2-blader. But, if it take 9 POUNDS to balance, maybe the RCS and some weight is the only way to get a good CG.

BTW, I'd be quite interested in your experiences running the RCS 150; maintenance, break in procedures, etc AND the different props you've tried. It would help me make a decision.

Regarding the cooling for the RCS with the cowl, definitely add baffling around the cylinder heads. I have heard running smooth air dams from behind the cylinder heads to the cowl flap exits helps keep the cooling air flow from becoming "confused" in the cowl. With 1:3 being the average inlet to vent size ratio, it would seem a LOT of venting is in order for the Z Cat.

I'll be very interested in seeing how your testing works out. Thanks for running this Thread!

Regards,
langerl

carlbecker

My Feedback: (3)

I use the Saito 450 3 cylinder in my 1/5 Wildcat. I used dummy engines to create a baffle for in coming air. Very tight to the cooling fins. I think you should consider a 1 to 2 ratio of air coming in to air leaving. I opened up the cooling flaps on my cowl and have not had problems this summer in 95 degree humid Virginia air.

Todd Jackson

My Feedback: (6)

ok here is some pics of the 150 on the Hellcat and the chunk of lead and see how close the cowl vents are.I think they need to be opened a little.Thanks Todd

Todd Jackson

My Feedback: (6)

few more

US185Damiani

The Carb is behind the engine correct?

If this is the case you will definitely go rich upon installing the cowl since now you have hot air entering the carb.
you may need to lean it a bit with the cowl on.

jeff naul

My Feedback: (16)

i think the question needs to be re-asked, is it normal to be able to feel the heat from the engine on the cowl? keep in mind there are now 5 cylinders under that cowl, no body is use to feeling their cowl for heat, especially when we are use to one cylinder pointing at the bottom. we never checked the temp just thought it was odd to feel heat in the cowl. jeff