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  #1  
Old 25-08-17, 13:05
dan mason dan mason is offline
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Wings,drag and wind resistance

Hi all.
Was out at Anglesey last weekend in beautiful sunshine but very windy conditions - huge headwind along the fast sections from church to rocket and down the final straight to the last hairpin.
How much effect does this have on a small single seater?
I was running a 15-50 sprocket arrangement and 250-570 rear tyre. Had the front wing flap on the second lowest setting of 6. And took as much rear wing off as I dared.
The car would only rev to 11000 rpm in 5th and wouldn't pull any harder in 6th when they easily pull 13000+ So I had another gear +2500rpm left. so my terminal speed was pretty poor.
From the sprockets I ran I expected it to easily rev out in 6th with a 2009 180bhp fireblade motor.
So either the cars not quite running at full power,is running too much wing or the headwind and drag associated was crippling the straight line speed!
Car is the ex darren gumbley force.thanks
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  #2  
Old 25-08-17, 13:17
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dopdog dopdog is offline
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Hi Dan,
Did you reach max revs in the first 4 gears?
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  #3  
Old 25-08-17, 13:26
dan mason dan mason is offline
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Yeah hit shift light in 4th
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Old 25-08-17, 15:02
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What top speed does that work out as Dan?
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Old 25-08-17, 15:12
dan mason dan mason is offline
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The nearest gear calc I can find is for a 2006 blade
And 11250 rpm in 5th gives
110 mph with a 22" rear tyre
115 mph with a 23" rear
The 570 radial is 22.6"
So I'd assume around 113 mph

But not sure how the 2009 motors are geared compared to te 06
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  #6  
Old 25-08-17, 17:04
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Dan,
You should be able to track down gearbox ratios online and then use Westgarage's excellent spreadsheet to get actual figures for your engine/sprocket/tyres combo.
other gear ration spreadsheets are available!

A headwind is bound to have an impact - "Windy" conditions could easily mean a wind speed of 10 to 20mph so you'd have to knock that off your expected terminal speed ifyou're driving directly against it.
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  #7  
Old 25-08-17, 17:32
dan mason dan mason is offline
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I used the westgarage converter for the 06 blade to get the figures I got.
And the wind was very strong (was blowing the timing gear over etc) so not sure how strong it was.
Thanks steve
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Old 25-08-17, 18:37
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http://www.gearingcommander.com

Dan use this it will load your bike ratios then just change the wheel diameter
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Old 25-08-17, 19:33
dan mason dan mason is offline
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Cheers simon. According to that I was geared for 137mph which was a big miscalculation by me. I'll get myself a 52t rear to get me to just under 130
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Old 30-08-17, 13:49
gixxerthou gixxerthou is offline
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My experience is that drag is an immensely important consideration with a small single seater. The headwind encountered after Church has a considerable affect on Vmax. Another 'good' one is a headwind around Honda at Pembrey. Nothing, however, in my travels has compared yet to a headwind at Kirkistown in 2016, it was severe enough to cause the wing bracket failure on a V8, and reduce an ideal gearbox on my small single seater from 6 gears to only 4! Mind you, the downwind straight had the thing reaching a (never repeated) speed that the brakes failed to cope with....
I guess the hills are less troublesome, but yes, with limited power, drag is a factor.
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