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  • May 23, 2022, 07:29:50 AM

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Author Topic: Cylinder clearance  (Read 518 times)

Offline Geoff Goodworth

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Cylinder clearance
« on: July 15, 2021, 12:05:25 PM »
I'm currently designing a model which requires a close fitting cowl around an FP 35/40 or LA 40/46. More than half the head will be out in the airflow.

How much clearance should  I allow between the inner sides of the cowl and the fins to ensure adequate cooling?

Offline Dan McEntee

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Re: Cylinder clearance
« Reply #1 on: July 15, 2021, 12:48:53 PM »
  It's not only clearance at the sides, but have plenty of open area BEHIND the cylinder to allow the air to escape. Air getting by the cylinder means nothing if it can't exit the cowling completely. The air actually goes through the fins of the cylinder and that is what does the cooling. What goes past the cylinder between in and the wall of the cowling isn't doing anything. The area for the cooling air to exit the cowling should be about 2 to 1 of the opening for the air to get in. Make sure that the inlet opening is located properly for that job. This actions creates a kind of vacuum that makes for a positive airflow when the airplane is moving through the air.
  Type at you later,
    Dan McEntee
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Offline Geoff Goodworth

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Re: Cylinder clearance
« Reply #2 on: July 15, 2021, 07:05:08 PM »
Thanks guys.

I was across the exit requirements Dan, and I was thinking 3x. Certainly, I have capacity for that.

The model is a semi-scale Reno racer inspired stunt model and I want to conceal the cylinder in a cheek cowl like the Yatsenkos do it.


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