Drive Shaft Twisting

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
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strad
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Joined: 02 Jan 2010, 01:57

Re: Drive Shaft Twisting

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Among other things I would reckon weight...
The engine is linked directly to the clutch, fixed between the engine and gearbox. Two manufacturers, AP racing and Sachs produce Carbon/Carbon F1 clutches which must be able to tolerate temperatures as high as 500 degrees. The clutch is elctro-hydraulically operated and can weigh as little as 1,5 kg.
http://www.f1technical.net/articles/66
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PhillipM
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Joined: 16 May 2011, 15:18
Location: Over the road from Boothy...

Re: Drive Shaft Twisting

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mep wrote: Why not just put some "real" springs in the cluth like it is done it customer cars?
Too heavy, and far too bulky to fit in an F1 clutch, and it doesn't really help against shocks back through the gearbox itself.

Dolsum
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Joined: 15 Jul 2011, 11:38

Re: Drive Shaft Twisting

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Hi All1

To know more about driveshaft twisting, we must know the torque. In one post mention around 240 Nm engine torque! right engine! after the gearbox we will have around 2000 Nm to 2500 Nm, peaks of 4500Nm, so twisting angles are quite considerable, around 60degress is not a crazy idea.

Cheers!

Jersey Tom
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Joined: 29 May 2006, 20:49
Location: Huntersville, NC

Re: Drive Shaft Twisting

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Dolsum wrote:around 60degress is not a crazy idea.
I disagree.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

munks
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Joined: 20 May 2011, 20:54

Re: Drive Shaft Twisting

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Dolsum wrote:Hi All1

To know more about driveshaft twisting, we must know the torque. In one post mention around 240 Nm engine torque! right engine! after the gearbox we will have around 2000 Nm to 2500 Nm, peaks of 4500Nm, so twisting angles are quite considerable, around 60degress is not a crazy idea.

Cheers!
I haven't re-read this entire thread to see what engines or cars you got those numbers from, but the original post was about F1 cars. And you're basically right, we need two numbers - the torque and then the driveshaft stiffness.

While an F1 car might have something around 300Nm of torque, the clutch can transmit quite a bit more in certain situations like standing starts or during shifts, around 1000Nm. 1st gear is usually going to be around 3.0, which gives us 3000Nm but I'll be generous and use your peak torque of 4500Nm.

The stiffness of a modern F1 driveshaft is usually going to be 200+ Nm/deg. The lowest I've heard of, which was in the not-too-distant past, was about 140 Nm/deg. That gives us a maximum of 4500/140 = 32 degrees, in what I believe to be an extreme case (in fact, using a modern clutch with really low gearing and an older driveshaft). In reality, I would guess no more than half that is ever experienced.

Caito
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Joined: 16 Jun 2009, 05:30
Location: Switzerland

Re: Drive Shaft Twisting

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20kg at 1meter lever to turn it one degree. That sounds a bit weak.. am I wrong?
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Robert.Gardner
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Joined: 28 Jul 2011, 10:14

Re: Drive Shaft Twisting

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Assuming a top speed of 320km/h, a fisrt gear max of 80km/h (a guess), max of 18000 RPM, and 485 wheel rev/km based on wheel diameter of 656 mm.
Top gear final drive ratio =(320x485)/18000
= 8.62:1
First gear about 4 times that @ 34.5:1

And if engine torque is around 274N-m (Wikipedia article on Formula One engines)
then at peak engine torque, the 2 axles combined, transmit an average of 9453 N-m

Of course with engine/clutch/transaxle inertia, on slippery/rough tracks the peaks could perhaps double that or more.


But in no way could I see the the axles would ever twist by 180 degrees without failing, let alone 6 times that. The reality is perhaps much much less before a fatigue failure would occur throughout the race.