IMAC Double Build, Carden Pro 124" Extra 300 40%

[thurmma]

Mark, you also have to remember, your motor is a high compression motor, it produces more power because the rings have a narrower tolerance, and thus, produces more heat. Only other way to over come this is by installing a blower to cool those heads!!

I don't have any trouble with heat after a run. By the time I get back to the pits the engine is back at about 205 on both cylinders. In the air they are peaking at 280 to 295, which is about 15 to 25 degrees cooler than the engine that was on the Blue LX. I didn't baffle it directly around the cylinders like I did on the blue one and also you had the negative pressure lips already done on the cowl so I left them in place This engine is running about 8 to 15 degrees difference from side to side at peaks

You said you were on the bottom of the cylinders or the back side of the cylinders?

That is awesome on the power Can't wait to see it fly. Sounds like you are thinking of leaping to Advanced this year.

 

[orthobird]

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[thurmma]

No problem Cam, @orthobird Just wondering how the temps were so much lower than mine. I am hoping to have the Blue LX with the JTEC pipes up and running by next weekend. That will be very interesting because I will have the same prop, engine and everything else so i can actually do a pretty much apples to apples comparison once I get some gas through the new engine

 

[Rusty 73]

Thurmma what kinda of power are you running in your iMac plane ????

 

[orthobird]

This is

 

[orthobird]

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[thurmma]

That is very interesting Cam. I always thought the hottest part of the cylinder was on the back side. What you drew out makes perfect sense, thank you. Time to fly! I have burned over 5 gallons so far and it is only February

 

[thurmma]

Thurmma what kinda of power are you running in your iMac plane ????

ZDZ180 on JMB canisters. Turns a Falcon 30 x 13 3 blade at 6300 to 6400 with no problem at all. My 33o LX weighs in at 44.5 lbs and I can fly the Intermediate sequence between half and 3/4 throttle. I can do a double snap on an upline and not lose any air speed. It just keeps on pulling.

 

[Rusty 73]

This is my bad drawing skills!! LOL>>>

View attachment 93939




Air travels in to cowl, then down, and air is on top first, then pushed down, thru baffle plate and thru the fins. so the top and back of the cylinders will be cooler than the bottom. Meaning, in the bottom is the shadow of the air flow.

View attachment 93940


View attachment 93942



real scale deal!!

Isn't that pretty.

Air enters into cowl from front and then air pressure builds up and the air is pushed down, where the pressure is higher, there is less flow, as pressure decreases towards the back, then the flow increases.
View attachment 93941


Hope this helps.

Disclaimer!!
I am not an engineer or even a pilot!

But this, I know, from my experience with sensor placements. If I place the sensor on top or in the back, it will not be as hot as if it is placed on the bottom.

This is very similar to how the REDBULL air raceers cool their Lycoming engines you should look it up .
Thats why i placed the rear fence up on the firewall and rear baffles around the back of the engine to cool the engine .
Your Bang on Cam

 

[Rusty 73]

Thurmma thats the dream power setup with the ZDZ on Cans , i have heard good things about them but never seen one perform


Cam hope this works REDBULL air race engines .