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Aero Questions, Especially for MGB racers
- Thread starter dcharnet
- Start date
Protech Racing
Well-known member
The car has no min weight rules. We ran out of good front glass, so we cut off the roof. lost about 45# between the roof and glass.
Do a You tube or google serach for "ogren/Crap can" or Ogren Turbo Jett. It should come right up with a short clip.
Do a You tube or google serach for "ogren/Crap can" or Ogren Turbo Jett. It should come right up with a short clip.
Protech Racing
Well-known member
http://www.instructables.com/id/Measure ... -your-car/
This testing is all on street.
Coast down stuff. Short story, measure 3 drops from a speed that is repeatable, both ways.
I ran @ 60 -45 mph, 1st pass, 14.7sec as run @ sebring, full tank.
( 1 pass = 3 runs, each direction)
***The mass must stay the same to match the inertia. So if you remove stuff, you must add back in the weight ..
Pass2, with canards off, 15.2
Pass 3, pass seat out, rear upper wing removed. 17.1 or so.
Pass 4, trim off the little crap hanging out, 17.5 +-
Noted, as the car gets better, it reacts to any draft or wind a liitle more.
400ft draft makes the run NG.
Video of the car from another car( with streamers) helped also. This car is basically a pickup truck body,with a large airdam. The air flows over the sides and into the rear body section, near the rear pas doors.
The low pressure in the foot wells shows by the hanging streamers. Any exhaust leak or fumes from the engine get sucked into the cockpit. This annoys me.. I will add a lower door scoop forcing air into the leg area , and add back on the canards at a much lower angle, 2* maybe. They just look badAasss.
More 0n track testing @ Sebring in the PDX group, 9/2/12
This testing is all on street.
Coast down stuff. Short story, measure 3 drops from a speed that is repeatable, both ways.
I ran @ 60 -45 mph, 1st pass, 14.7sec as run @ sebring, full tank.
( 1 pass = 3 runs, each direction)
***The mass must stay the same to match the inertia. So if you remove stuff, you must add back in the weight ..
Pass2, with canards off, 15.2
Pass 3, pass seat out, rear upper wing removed. 17.1 or so.
Pass 4, trim off the little crap hanging out, 17.5 +-
Noted, as the car gets better, it reacts to any draft or wind a liitle more.
400ft draft makes the run NG.
Video of the car from another car( with streamers) helped also. This car is basically a pickup truck body,with a large airdam. The air flows over the sides and into the rear body section, near the rear pas doors.
The low pressure in the foot wells shows by the hanging streamers. Any exhaust leak or fumes from the engine get sucked into the cockpit. This annoys me.. I will add a lower door scoop forcing air into the leg area , and add back on the canards at a much lower angle, 2* maybe. They just look badAasss.
More 0n track testing @ Sebring in the PDX group, 9/2/12
Protech Racing
Well-known member
Update, picked up 9-11 mph by cleaning up the car. (Chumpcar @ Sebring)
My Engineering Son and I have built a "wind table". It is merely a front end rack and one extra large fan that blows air @ near 60mph. We can also set the car on the scales.
We use it in conjunction with the coast down testing done on my local 6000ft airport runway.
We do the base line coast down runs, and than onto the table to get tuft tested, back to the runway,etc.
When we think that we have run up against the rules and/ or the car, we call it done.
The HP car is next, we have very good base line real world speed to work from. The nose is really ugly old IT level air dam /fenders. Should be fun to find some more speed for this car.
My Engineering Son and I have built a "wind table". It is merely a front end rack and one extra large fan that blows air @ near 60mph. We can also set the car on the scales.
We use it in conjunction with the coast down testing done on my local 6000ft airport runway.
We do the base line coast down runs, and than onto the table to get tuft tested, back to the runway,etc.
When we think that we have run up against the rules and/ or the car, we call it done.
The HP car is next, we have very good base line real world speed to work from. The nose is really ugly old IT level air dam /fenders. Should be fun to find some more speed for this car.