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Old 01-05-2012, 11:29 AM   #1 (permalink)
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What about placing radiators in the back to fill-up Kamm low rear pressure?

What you guys think of an aero design that places the radiators (and maybe even the exhaust) at the back of the car?

So their heated air (thus with high pressure) compensates rear low pressure zones?

Remember piston engines are at most 30% efficient. So most fuel is wasted as heat. What about using this lost heat to improve aerodynamics?

Many formula cars try to place radiators in the sidepods to minimize cooling drag.
What about a similar design for front-engined cars?
Maybe you'll need to place radiators in the back instead, so you can still use the sides to open the doors?


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Old 01-05-2012, 12:13 PM   #2 (permalink)
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I have thought about it - two problems. One, you need flow THROUGH the radiator to cool it. Hard to get flow through the radiator back there.

As for exiting the hot air back to the dead spot, good idea I think.
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Old 01-05-2012, 12:34 PM   #3 (permalink)
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This has actually been used in piston-engined aircraft, notably the P-51 Mustang. See Meredith Effect - Wikipedia, the free encyclopedia

As for input air, why not ducts in the sides of the car? And then you could make it mid-engined, kinda like this: Lotus Elise - Wikipedia, the free encyclopedia
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Old 01-05-2012, 05:09 PM   #4 (permalink)
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Hillman in the 1960's built a rear engined car named the Imp which had a radiator ducting into the rear panel and the intake was on the rear deck where the trunk / boot would normally be.

Apart from adding a little weight at the rear and having the extra pipework to take the fluids to and fro there seems to be few downsides.

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Old 01-05-2012, 05:58 PM   #5 (permalink)
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Quote:
Originally Posted by Peter7307 View Post
Hillman in the 1960's built a rear engined car named the Imp which had a radiator ducting into the rear panel and the intake was on the rear deck where the trunk / boot would normally be.

Apart from adding a little weight at the rear and having the extra pipework to take the fluids to and fro there seems to be few downsides.

Peter.
For a mid-engine car, there would be far less "pipework" than having a traditional radiator. I had a 1991 MR2 which has the radiator up front. Getting the air out of the coolant lines was a little tricky because they were so lengthy, running under the passenger compartment to the nose of the car. They could have easily put the radiator in the goofy mini-trunk behind the engine and saved a lot of plumbing.
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Old 01-05-2012, 06:23 PM   #6 (permalink)
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Quote:
Originally Posted by Big time View Post
What you guys think of an aero design that places the radiators (and maybe even the exhaust) at the back of the car?

So their heated air (thus with high pressure) compensates rear low pressure zones?

Remember piston engines are at most 30% efficient. So most fuel is wasted as heat. What about using this lost heat to improve aerodynamics?

Many formula cars try to place radiators in the sidepods to minimize cooling drag.
What about a similar design for front-engined cars?
Maybe you'll need to place radiators in the back instead, so you can still use the sides to open the doors?
The 1984 Ford Probe-IV had such technology.
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Old 01-05-2012, 09:32 PM   #7 (permalink)
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I wonder if this would even be worth it, especially if you have a front-engine layout. What with the plumbing necessary to cycle the water, the extra weight from the extra liquid, and the reduced airflow.
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Old 01-05-2012, 09:40 PM   #8 (permalink)
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Quote:
Originally Posted by jamesqf View Post
This has actually been used in piston-engined aircraft, notably the P-51 Mustang. See Meredith Effect - Wikipedia, the free encyclopedia

As for input air, why not ducts in the sides of the car? And then you could make it mid-engined, kinda like this: Lotus Elise - Wikipedia, the free encyclopedia
I don't get how this works. Heating causes air to expand, but why would that expansion force be applied to the rear any more than to the front of the radiator? It should resist airflow from the front just as much as it pushes air out the back.
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Old 01-06-2012, 12:50 PM   #9 (permalink)
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Originally Posted by jamesqf View Post
This has actually been used in piston-engined aircraft, notably the P-51 Mustang. See Meredith Effect - Wikipedia, the free encyclopedia
I think you'll find the P-51's more handsome and slightly older (and IMHO better looking) "uncle" from overseas, the Supermarine Spitfire, did it first - and then allowed the P-51 to "borrow" its engine as nothing suitable was available at home. *

*(I should acknowledge of course that the Merlins used in the Spitfire were pretty much "hand built" due to the design which was very inefficient for production. The P-51 version of the Merlin (redesigned in the US during WW2) was transformed into a mass produced engine, and improved along the way. Created by geniuses, improved by very smart engineers.)
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Old 01-06-2012, 12:58 PM   #10 (permalink)
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I don't get how this works. Heating causes air to expand, but why would that expansion force be applied to the rear any more than to the front of the radiator? It should resist airflow from the front just as much as it pushes air out the back.
It didn't add "thrust" so much as to remove the "drag" from having ducting to the radiator underneath - so you get the coolling effect without sacrificing speed.



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