aero / Vmax / box link

[laurent_caen]

hello, I would have liked to know if from the only data of the maximum speed and gear ratios of the gearbox, we could approximately deduce the aerodynamics of a vehicle (Scx) and if so by what formula
thank you in advance

[Rulian]

You need at least the instantaneous power of your machine developed at a given speed. With that we can maybe evaluate the cx (including friction due to rolling) with basic formulas. But certainly not with the reports from your inbox.

After to have instant power it is tense. Maybe with the engine fully in fifth gear, headwind, we can consider that you have reached maximum power and you have to note the speed ... but hey, you better not cross a radar ... and I I'm not sure it would be correct.

[Christophe]

1) There are the instantaneous power formulas, page 8 of this report: https://www.econologie.com/telechargement-61.html

With a few approximations, notably on the engine and transmission efficiency, you should easily find the value of the SCx. But this value will obviously be approximate ...

I think it may be easier to consult the charts and archives if your vehicle is not too recent ...

2) We recently talked about the power necessary for the advancement of a vehicle, we had some interesting figures, do a research on the forum https://www.econologie.com/forums/search.php

[Christophe]

I think we talked about it here: https://www.econologie.com/forums/et-l-aerod ... t1738.html

Look what I found there:

[laurent_caen]

thanks to you i will take a look