View Full Version : how fast...
billybug1
24-05-2007, 06:08 PM
how fast would a 19t motor go with a 17t esc
thanx will:confused:
Northy
24-05-2007, 06:12 PM
very
billybug1
24-05-2007, 06:14 PM
but in mph/kmph if you could
MK999
24-05-2007, 10:20 PM
Between 1 and 200ish depending on a huge multitude of factors.
bigred5765
25-05-2007, 08:32 AM
but in mph/kmph if you could
depends on
the car /track / length of the straight/gearing/battery's/motor/tyres/speedo
Chequered Flag Racing
25-05-2007, 08:52 AM
but in mph/kmph if you could
well if it's a B4 with
19T motor revving to 30,000rpm
kit spur
25t pinion
80mm tyres (schumacher spikes)
it should theoretically do 33.786mph or 54.057kph
MK999
25-05-2007, 08:54 AM
depends on
the car /track / length of the straight/gearing/battery's/motor/tyres/speedo
air temp/track temp/tyre temp/humidity/ air pressure? (must have a small effect ;p)/driver !/surface
well if it's a B4 with
19T motor revving to 30,000rpm
kit spur
25t pinion
80mm tyres (schumacher spikes)
it should theoretically do 33.786mph or 54.057kph
I downloaded that programme you have, added the B4.
Apparently, with my mamba max 5700kv in, with the right gearing, I should be able to do 115m.p.h
Next project I think. After the custom car, custom car RC website, and then this :D
MK999
25-05-2007, 09:30 AM
It's out, way out... it doesn't into account any kind of resistance, mechanical or aerodynamic, according to that if you put a big enough motor overgeared in a brick it'd do 300mph
sosidge
25-05-2007, 10:03 AM
how fast would a 19t motor go with a 17t esc
thanx will:confused:
Quick tip about the world of RC racing. The one question that nobody wants to answer is "how fast will this go".
A few reasons...
- It is impossible to know how fast the car is actually going as the cars don't have speedometers
- Racing cars are geared to be fast around a lap not fast in a straight line
Finally, and most importantly...
- Asking how fast it goes is a real noobie question, it's like taping a "kick me" sign to your own back :D
Anyway, a B4 with a 19T motor will go sufficiently fast to have fun and that is all that matters. You'll actually get around a track almost as quick as a full modified car.
jimmy
25-05-2007, 10:16 AM
I measure some speeds with my HOTWHEELS radar gun at Bury Metro coming down the first 1/3rd of the straight cars with mega brushless systems were doing 31mph or so.
Any quicker and you'd take off.
http://www.girl.com.au/graphics/mattel_hotwheels_radar.jpg
bigred5765
25-05-2007, 10:19 AM
from what i saw at the end of the straight i think a few did
Spencer Mulcahy
25-05-2007, 10:22 AM
Mat did in one round:)
bigred5765
25-05-2007, 10:31 AM
minus one wheel and all lmao
but JONNY THE BULLET FAST PANTS is the man to ask about speed
Spencer Mulcahy
25-05-2007, 10:36 AM
The Bullet would not be seen dead with a 19 in his ride.:) :) (unless its raining at Bury on sunday):)
sosidge
25-05-2007, 10:37 AM
I measure some speeds with my HOTWHEELS radar gun at Bury Metro coming down the first 1/3rd of the straight cars with mega brushless systems were doing 31mph or so.
Any quicker and you'd take off.
http://www.girl.com.au/graphics/mattel_hotwheels_radar.jpg
Now that is cool! Where did you find one of those?
jimmy
25-05-2007, 10:40 AM
I got it from santa! I think from ebay in the USA - not sure they sell them over here, I looked but couldn't find. It's cheaper than buying a more 'serious' looking speed gun, and seems to work well.
http://images.amazon.com/images/P/B000EHLB0M.16._SCLZZZZZZZ_SS260_.jpg
Chequered Flag Racing
25-05-2007, 10:55 AM
It's out, way out... it doesn't into account any kind of resistance, mechanical or aerodynamic, according to that if you put a big enough motor overgeared in a brick it'd do 300mph
like it says in post it should theoretically do
sosidge
25-05-2007, 02:55 PM
No, no, no. Not even in theory.
The theory behind that speed calculator is bogus. You cannot calculate speed from no-load RPM and a gear ratio.
Speed is about POWER, not RPM.
And that POWER needs to overcome loads of resistance, mainly mechanical and aerodynamic drag.
So if you are going to waste your time with a speed calculator you may as well waste your time with one that is based on published motor power, the mass of the vehicle, and a generalised calculation for drag and rolling resistance.
A community control police man turned up at tivvy outdoor a few weeks ago with his speed gun, He caught me at 31mph and some others at 34mph. I was running a 13t in my B4. I got 3 point on my license as it was a 30mph zone!! :p
Chequered Flag Racing
25-05-2007, 03:12 PM
I got it from santa! I think from ebay in the USA - not sure they sell them over here, I looked but couldn't find. It's cheaper than buying a more 'serious' looking speed gun, and seems to work well.
here's one (http://cgi.ebay.co.uk/New-Hot-Wheels-Real-Radar-Gun-meas-Baseball-Bike-Car_W0QQitemZ180119396529QQihZ008QQcategoryZ73916Q QrdZ1QQssPageNameZWD2VQQcmdZViewItem) but it's in the states:(
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