Baffle or no baffle, that is the question

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3 years 10 months ago - 3 years 10 months ago #23983 by JonTappin
Replied by JonTappin on topic Baffle or no baffle, that is the question
Looks good Jeff but you need to open up in front of the crankcase heat sinks as well.

Saved yourself 25 quid as we'll :)
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3 years 10 months ago #23984 by Hobby1964
Replied by Hobby1964 on topic Baffle or no baffle, that is the question
Thanks Jon. But the 60 doesn’t have those heat sinks on it
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3 years 10 months ago #23985 by kevinross
Replied by kevinross on topic Baffle or no baffle, that is the question
Extracted the text below from a full-size aviation document. All common sense, and of course the principle are the same in models. The main difference as you are probably aware is the full size have mechanical doors which can be operated to increase outlet airflow at low speed.
It says is you need to use the high velocity air on the cowl outlet to draw the cooling air out while bearing in mind the much lower velocity air at the baffles which should be able to flow freely. On the full size radial, a smoother inlet airflow is provided by the adjacent cylinders. So i'm thinking it might be beneficial to create a curved surface ( like a pseudo cylinder ) in stead of a flat face which may tend to create turbulent air. You could paint a cylinder on it to improve the look.
Thats what i plan to do on the Stearman.

Three main avenues of approach to the problem of increasing the low baffle pressure drops existing at very low airplane speeds in order to obtain the velocity of cooling air necessary for increased heat rejection, are studied: 1. Use of the propeller slipstream to induce a depression after the baffle passages. 2. Use of the propeller slipstream to build up a pressure before the baffle passages.

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3 years 10 months ago #23988 by Hobby1964
Replied by Hobby1964 on topic Baffle or no baffle, that is the question
Yes I see where you’re going with that Kevin but I would have thought that the Corsair type cowl will be under pressure from the prop and the air pressure induced from the forward motion of the aircraft. I suppose it’s a bit of a balancing act of how complicated you want to get and what the actual cooling effect the different methods actually make to the engine temperature. Also, on the Corsair the cowl has a bit of a flair to it and the fuselage has a tapered front on it so I would think the air passing over the outer surface would produce the effect of drawing the air from the cowl as well
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