Quote:
Originally Posted by AeroMcAeroFace
But other than accessory losses, everything else is changing due to the increased engine speed.
I am not saying that a 5% increase in top speed means an exact 10% decrease in drag, there are too many variables at play to say absolutely.
however you can say with absolute certainty that a fixed throttle position will give you a higher top speed if drag is reduced, there is no way you can argue against that.
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1) Technically, if the accessories are belt-driven, hysteresis losses in the rubber of the serpentine or cog-belt will increase losses arithmetically with rpm, like the tires with velocity.
2) For drag versus top-speed, Hucho reported a 30% delta- Cd -to-10% delta- velocity relationship as of December, 1986. There may exist more contemporary reporting on this. Don't know.
3) Yeah, lots of variables, which Julian spells out many in the video. I've collected materials since 1974, and I may have some obscure data easily missed in all these intervening decades.
4) You're absolutely correct about expectations for a higher top speed. I don't think it could be argued otherwise. Top-speed testing is a form of ' throttle-stop' testing. Spirit picked up 19-mph ( 31- km/h ) that we know of. And that was with a 920-lb weight penalty ( 418 Kg ).