Radiator duct

[tauruck]

Guys, I'm a lone voice in the wilderness here. My question concerns my radiator duct on my salt project. I'm busy getting the plug ready for molding and I've reduced the original radiator duct in size. My radiator is 28" wide and the duct in the nose is that wide but I've reduced the height from 6" down to 1 3/4". It's shaped with a good profile and when done I'll have the rad in a sealed box etc. Is the size adequate is what I'm asking. Projected speed is hopefully around 200. Thanks.

[Rex Schimmer]

Do you have to run a radiator? A box of water and a pump can be much more aero than a radiator regardless of how well you duct it and get the air in and out.

Rex

[Stan Back]

. . . and having to have a radiator doesn't mean you have to put water in it.

[tauruck]

This why I asked. We'll be running twin turbos on the motor like they do in Pro Mod. I don't have a background in salt racing and nobody here in South Africa has done this type deal before. Being a newbie, I thought I might get a little more detail from the members here.

[manta22]

Do you have to run a radiator? A box of water and a pump can be much more aero than a radiator regardless of how well you duct it and get the air in and out.

Rex

Rex;

Didn't the P-51 Mustang gain a few knots by the hot air exhausted from its radiator?

Regards, Neil  Tucson, AZ

[Rex Schimmer]

Neil,
As I understand the P51 did have one speed range when the inlet size, the expansion duct, the heat load from the radiator and the exit duct could have made some additional thrust. The whole design of the inlet and exit duct system and radiator is probably beyond most of us and the cost when compared to just a water tank and a big water pump probably is not worth the effort.

Tauruck,
Your motor sounds pretty serious, just remember that you want a lot of water circulating through it to make it live and also plenty of water pressure. I always go by my friend Stu Van Dyne's water rule, 10 gallons per minute per 100 horse power which means a pretty big pump if you are looking at 1000 + hp.

Rex

[hotrod]

Rex;

Didn't the P-51 Mustang gain a few knots by the hot air exhausted from its radiator?

It is often called the Meredith effect -- It was more a case of negating radiator drag than producing actual thrust. The thrust from the heat gain and expansion largely canceled out the drag inherent in the radiator's internal drag.

http://www.pprune.org/aviation-history-nostalgia/387708-napier-heston-belly-scoop-first-one.html

Lee indicates that the propeller thrust at full power was about 1000lbs. However, the drag of the cooling radiator was of the order 400lbs! That is, nearly half the available thrust was required just for cooling the engine

By careful design of the radiator and its ducted cooling system, it was possible to use the heat released by the radiator to generate 350lb of thrust, thereby reducing the net drag of the cooling system to just 50lbs. ...

Larry

[38flattie]

I'm not the smartest guy, so it's not surprising that I'm confused.

In your first post, you say you're going to run a radiator in a box, so why do you need an air duct for the radiator? Fill the box with water. My radiator in a box is in the trunk.

Or is it an air inlet for the engine?

[tauruck]

The front of the car is the same as you'd find in a NASCAR Sprint cup  car with air coming through the grille located low down and through the radiator which is shrouded. A radiator box is a term we use here to describe the shroud.