Active rear wing test
09-26-2013, 11:53 AM
#101
Keep reading until you get to the part about the Traqmate data failure.
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09-26-2013, 04:16 PM
#102
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09-28-2013, 11:50 AM
#105
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--Ryan nice to see you back
I looked into it abit, but not like the corvette with the Abrams exhaust fan. I was thinking of 2 120mm Ducted Fans from RC Planes. I knew that the fans are made for propulsion and not sucking, so start out with a small one then see the power of that one first.
I looked into it abit, but not like the corvette with the Abrams exhaust fan. I was thinking of 2 120mm Ducted Fans from RC Planes. I knew that the fans are made for propulsion and not sucking, so start out with a small one then see the power of that one first.
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09-28-2013, 06:39 PM
#106
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You would need an order of magnitude more power than that to see any effect. A Miata-sized sucker would need 30-60 hp of air-moving power to generate a significant effect. You could probably feel something with 15hp and perfect sliding skirts.
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09-28-2013, 07:08 PM
#107
Interesting project. In a discussion on ground effects for Sports2000 race cars, one of the true studs to ever race and/or engineer in the class gave a strong opinion that any gain in downforce is most likely wiped out by a loss in driver confidence - ground effects are so reliant on maintaining ride height, that you just won't have reliable grip braking into a corner due to brake dive changing the chassis height.
I offer this only to reinforce that the control system for a movable rear wing has to be absolutely reliable. The grip has to be there in every corner else the driver won't have the confidence to use it.
IIRC, the movable wings on the Chaparrals were controlled by a pedal, and returned to max downforce position when the pedal wasn't down. That was obviously a lot easier for the driver to manage since the cars used an automatic transmission, but a good fail-safe mode can't be under-valued.
I suppose the steering might go a little light if the max downforce mode was enabled at high speed. If you could tie-in movable front canards, the car could be kept balanced in either mode, just really draggy in fail-safe.
I offer this only to reinforce that the control system for a movable rear wing has to be absolutely reliable. The grip has to be there in every corner else the driver won't have the confidence to use it.
IIRC, the movable wings on the Chaparrals were controlled by a pedal, and returned to max downforce position when the pedal wasn't down. That was obviously a lot easier for the driver to manage since the cars used an automatic transmission, but a good fail-safe mode can't be under-valued.
I suppose the steering might go a little light if the max downforce mode was enabled at high speed. If you could tie-in movable front canards, the car could be kept balanced in either mode, just really draggy in fail-safe.
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09-29-2013, 02:44 AM
#108
Quick refresher please: Is the goal to move the wing to maximum downforce or past stall to use as an air brake?
I thought about this at our local track Thursday. T1 is a very fast left hander at the end of the straight (140+ to >100mph) followed 200 feet later by a ~60mph hard left up a steep incline. Discussing this with a few other drivers, we discovered some of us brake slowly and trail around to the T2 turn in and others brake hard into T1, maintenance throttle through T1 and brake again for T2. A front running spec could probably go flat through T1 and get shut down enough for T2.
In this scenario, a max downforce setting would probably be OK for either style but the air brake would be pretty scary for the trail braker when he realized the car was only stable in a straight line.
I thought about this at our local track Thursday. T1 is a very fast left hander at the end of the straight (140+ to >100mph) followed 200 feet later by a ~60mph hard left up a steep incline. Discussing this with a few other drivers, we discovered some of us brake slowly and trail around to the T2 turn in and others brake hard into T1, maintenance throttle through T1 and brake again for T2. A front running spec could probably go flat through T1 and get shut down enough for T2.
In this scenario, a max downforce setting would probably be OK for either style but the air brake would be pretty scary for the trail braker when he realized the car was only stable in a straight line.
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09-30-2013, 11:44 AM
#109
This is an air brake, although it could be used to go to max downforce. Under max braking, the drag is more effective at slowing the car than downforce. It will also add stability to the car, the same way that throwing out a parachute will keep a car pointed straight. However, it won't add to cornering grip.
Yes, it will likely change the balance of the car under certain conditions. So the driver may have to adapt his line, the same way the line changes if you change horsepower significantly.
I'll be testing this weekend on a track that I know much better, and which includes a very interesting braking zone that is mid-corner. So we'll see how it works. That's why we test instead of just posting to the internet, to learn the truth of things. Well, it's why some of us test anyhow.
Yes, it will likely change the balance of the car under certain conditions. So the driver may have to adapt his line, the same way the line changes if you change horsepower significantly.
I'll be testing this weekend on a track that I know much better, and which includes a very interesting braking zone that is mid-corner. So we'll see how it works. That's why we test instead of just posting to the internet, to learn the truth of things. Well, it's why some of us test anyhow.
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11-05-2013, 03:18 PM
#110
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This is an air brake, although it could be used to go to max downforce. Under max braking, the drag is more effective at slowing the car than downforce. It will also add stability to the car, the same way that throwing out a parachute will keep a car pointed straight. However, it won't add to cornering grip.
Yes, it will likely change the balance of the car under certain conditions. So the driver may have to adapt his line, the same way the line changes if you change horsepower significantly.
I'll be testing this weekend on a track that I know much better, and which includes a very interesting braking zone that is mid-corner. So we'll see how it works. That's why we test instead of just posting to the internet, to learn the truth of things. Well, it's why some of us test anyhow.
Yes, it will likely change the balance of the car under certain conditions. So the driver may have to adapt his line, the same way the line changes if you change horsepower significantly.
I'll be testing this weekend on a track that I know much better, and which includes a very interesting braking zone that is mid-corner. So we'll see how it works. That's why we test instead of just posting to the internet, to learn the truth of things. Well, it's why some of us test anyhow.
Sorry no idea how to embed this vid into the forum :( thanks chap below for showing me how to 👍
Wished I'd thought of your brackets inside the boot wall.
Last edited by HeresJohnny; 11-05-2013 at 06:15 PM.
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11-05-2013, 11:15 PM
#113
IIRC, the movable wings on the Chaparrals were controlled by a pedal, and returned to max downforce position when the pedal wasn't down. That was obviously a lot easier for the driver to manage since the cars used an automatic transmission, but a good fail-safe mode can't be under-valued.
Last edited by Rennkafer; 11-05-2013 at 11:50 PM.
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11-05-2013, 11:43 PM
#114
http://www. youtube.com/ watch?v =X6r m5HSDy6g
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05-28-2014, 08:50 AM
#118
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Without all that you'd just be getting an idea of how much aero-brake the wing gives, but you wouldn't know how much difference you'd get from having more (or possibly less, if the wing is fully stalled) rear traction.
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05-28-2014, 12:30 PM
#120
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The true benefit wouldn't be known just by doing a quick back-to-back test. Since the wing will affect to some extent the amount of traction in the rear, for the test to fully reveal the benefit, you'd have to do several tests without it (or with it set at a constant AOA) while adjusting the brake balance until you find the best stopping time you can achieve with that setup. Then you enable the active wing, and do the whole thing again.
Without all that you'd just be getting an idea of how much aero-brake the wing gives, but you wouldn't know how much difference you'd get from having more (or possibly less, if the wing is fully stalled) rear traction.
Without all that you'd just be getting an idea of how much aero-brake the wing gives, but you wouldn't know how much difference you'd get from having more (or possibly less, if the wing is fully stalled) rear traction.
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