mangogrooveworkshop
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| posted on 14/6/10 at 11:40 PM |
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quote:
Are you sure it's aerodynamics and not something else in the setup?? My indy is not the best at speed at the moment, main problem is bump-steer
that I have yet to dial out and possibly the old caster problem, makes things feel a little light up front at 70mph. Dan
Na I sorted that s***T out last season with a whole set of new bones that make the car naturaly self center with out springs and bodging carry on.
The air is lifting it as we have done tests running into the wind and running with it....east west runs on the same bit of tarmac.
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sucksqueezebangblow
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| posted on 15/6/10 at 09:30 AM |
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Diffuser;
quote:
Originally posted by mangogrooveworkshop
Its at 70 that we start lifting
Lower speeds I dont care what its doing just want the nose to stay put at the higher cruising speeds.
Cost to me is almost zero its just the time that it will cost me.
I had thought of the panels in the bones...
Ive also got most of the materials to make it.
So if anyone has ideas please tell me
Ok, here goes. I DO believe attention to aerodynamics is well worth the effort. I agree that below 70 the benefits will be insignificant, but I intend
to take my car up to 120 or more (depending on which drop gears I fit).
Wings; most locost arches have a nice round curve to them, the top surface acts like the top surface of a wing, and if the air flow adheres to
them, which it will, you get lift. Think Audi TT, numerous owners went through hedges backwards before Audi added a small gurney flap to the rear of
the car. The simple solution is to break the airflow away using small tabs or "gurney flaps" across the back of the arch, a little way
behind the top of the arch. I've got racing arches at the front which have a "kick" at the back but are to my mind too smooth to
work efficiently (moulding process does not allow harder edge) so I plan to put small gurney flaps on the back of each kick to break the airflow away
properly. I plan to fit similar flaps across the back of the rear arches which being bigger would otherwise create more lift.
Undertray; I think the biggest gains can be made by fitting a full undertray (and even more combined with a diffuser). This will clean up the
airflow under the car and stop the engine bay and and rear underside acting like parachutes, with high and low pressure areas shifting about all over
the place at high speeds.
Splitter; I also feel a splitter is of value. Essentially when a locost nose cone is stuffed through the air, air is forced over, under and
around the 'cone. This creates high pressure air all around the 'cone. The only bit that that may be problematic is the high pressure
under the 'cone which will create lift under the cone. A splitter will address this. It is called a splitter because it splits the air going
under the car from the air going around or over the car. Like a knife it cuts a clean slice of air that goes straight under the car with no increase
in pressure. There is pressure above the splitter, but this now bears down on the splitter creating down force (or reducing lift) as the air is forced
to change direction and flow around the cone instead of underneath. Needless to say there is not much benefit if there is no undertray to keep the
flow clean under the car.
Diffuser; Diffusers can also be of benefit if you have a full undertray. Essentially the air flowing under the car suddenly finds itself in a
venturi (widening cone) and has to expand into it (laws of physics) streching it and lowering its pressure creating downforce. The effect can be
further increased by setting the floor height of the front of the car lower by a few inches than the floor height of the back of the car, effectively
creating a mild venturi between the floor of the car and the road, for the full length of the car. The front floor should NEVER be set higher than the
back as this crams air under the car and creates lift.
Beyond that there is not much more that can be done without adding wings. Cannards probably create some downforce (and drag) but they look cool so why
not!
Better to Burnout than to Fade Away JET METAL ~ AndySparrow © 
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supercat
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| posted on 28/6/10 at 03:31 PM |
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Has anyone got pictures or drawings of a splitter on a 7 type car?
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vinnievector
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| posted on 29/6/10 at 09:40 PM |
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I have made canards to cover up my unsightly lamp brackets and put some down force in at the front to take off the effect of the front wings not sure
works but looks nice
they are an inverted wing section made from 22SWG T3 alloy with paxalin end fairings ,they will be painted to match the body work.
 
Rescued attachment Isle of Wight 217.jpg
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