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Quote:
Originally Posted by Talos Woten
Howdy all!
I'm currently designing a nose cone for Champrius. The key to the nose cone will be a variable area inlet for the radiator right at the tip. I've bought these piano hinges:
https://www.amazon.com/dp/B07PP1XXQT
and plan on having a 24" x 3" opening for the inlet, with one hinge on top, and the other on bottom. That will give me 0-72 sq ins which should be enough to cover all cold to hot weather conditions. Viewed from the side, it's basically the leading edge "front" of a triangle whose base is the radiator (though with some more curvature to guide airflow).
Everything I've read says that aero-shaping for radiator inlets is crucial to proper airflow. It's the reason why virtually every grille in the world is inset slightly in some kind of curved bumper / fender. So I want to make piano hinges like little aerofoils / curve them smooth somehow.
Does anyone have any ideas on how to do that?
Keep in mind the main constraint: whatever we do has to be tough. This part will, without doubt, receive more wear and abuse than every other aeromod on the car. Not only does it have to withstand a constant +15-60 lbs per sq ft of pressure above atmospheric, it's going to get peppered by road debris and other crap while driving.
I'd also like to use a common part or material and re-purpose it, rather than having to custom make something myself. To give an example, the rest of the nose cone will be made from a Brute plastic trash can, cut up and attached to an aluminum frame. That has the natural curved shape we want already, and is tough enough to withstand the aero-abuse.
I've thought about slicing a pipe, but not only could I not find a pipe small enough, I couldn't think of a way to adhere it to the hinge. The hinge has holes in it, so we can potentially use screws if needed.
Any thoughts? |
In 1963,Walter Korff, chief aerodynamicist for Lockheed Aircraft Company, and designer of the 409-mph Goldenrod LSR Streamliner, published an SAE Paper which included his design recommendation for a cooling inlet, which may have been borrowed from the 1959 Lotus.
Korff recommended that the net opening be as 'wide' as the radiator, 1/6th the radiator height, and the interconnecting, diverging ductwork be at least one radiator height in length.
To eliminate a vena contracta entry loss ( which invisibly chokes off the airflow) all sides of the opening are bell-mouthed. ( I used a 1" radius for Bonneville and highway )
If the 'pin' of the piano hinge in 'inside', mounted 'flat' between flanges of the stationary upper surface, and moving lower surface, with a 'rolled' gap-filler, the moving panel will always be closed off at the top, as a roll-top desk is, while the lower portion modulates the area of the opening.