Getting a drag.

**vtec** · 10th June 2006, 12:37

I reckon that once you are over about 120k/hr the effects on a less powerful bike such as a streetstock machine are probably more noticeable than say on an F2 machine. It definitely helped me on Pukekohe chasing F3 bikes, with drafting very closely I managed to stay with noticeably more powerful machines up until I hit revlimiter in 6th with the standard sprockets. Due to drafting, I got the bike up to it's max speed in a very short space of time, half way down the back straight at Puke. Without drafting, I probably only got to the limit once. Drafting definitely has a huge impact on lesser powered bikes. Also would have a really good impact on more powerful bikes at higher speeds too.

Here's a pic of what's happening, it's the best I could do in paint.

**texmo** · 10th June 2006, 12:58

nice vtec chur for that. I still havent heard back from vic club so im starting to sweat.

**vtec** · 10th June 2006, 13:21

Hmm, don't let it get to you tex. But if you are really worried, you could just give someone a call. Or get in touch with whoever it was that is helping you out from VMCC

Also for those skeptical about the benefits of drafting, you should seriously try doing a cycling race to increase your understanding. The benefits of drafting in cycling are huge, that's why the peloton nearly always mow down any breakaways, that is unless the peloton are buggering around playing games which they too often do, as was shown at the Melbourne Olympics in the womens 50k road race... what an embarrassment. The peloton just buggered around for about 75% of the race. But once they choose to go, because they have got lots of people drafting, they are using up way less energy as a whole, and are going a lot faster than any lone rider could possibly do.

**sAsLEX** · 10th June 2006, 13:29

Originally Posted by vtec

Here's a pic of what's happening, it's the best I could do in paint.

The aeros to the rear of something are also very important to achieving aerodynamic goodness.

________
|...........|
|...........|
|...........|
\........../
..\......./
....\.../
......\/

will fall slower than

....../\
...../...\
.../......\
../.........\
|...........|
|...........|
----------

**texmo** · 10th June 2006, 13:35

And heres me thinking racing was easy...

**N4CR** · 10th June 2006, 13:37

Originally Posted by texmo

And heres me thinking racing was easy...

It is, you just need to learn from the black flame rider and krieg them all. Word.

Hmmm it's all about airflow disturbance really, if you REALLY want I can scan some pages about basic aerodynamics and coefficient of drag between different shape diagrams and stuff like that...

**Korea** · 10th June 2006, 16:42

Originally Posted by N4CR

It is, you just need to learn from the black flame rider and krieg them all. Word.

Hmmm it's all about airflow disturbance really, if you REALLY want I can scan some pages about basic aerodynamics and coefficient of drag between different shape diagrams and stuff like that...

Oo-eeeer~ go on then ~ sounds educational!
Waiting for the update...

**sAsLEX** · 10th June 2006, 17:37

Originally Posted by Korea

Oo-eeeer~ go on then ~ sounds educational!
Waiting for the update...

A real world result of the drag thing http://ame-www.usc.edu/rsg-old/gva/5/5c.htm

**N4CR** · 10th June 2006, 17:38

Originally Posted by Korea

Oo-eeeer~ go on then ~ sounds educational!
Waiting for the update...

Oookay I got off my arse and scanned some stuff for you, 1st page is most relevant detailing disturbed airflow and the suction affect it creates..

Any more questions just ask I'll try explain it better.

**vtec** · 11th June 2006, 14:14

Originally Posted by sAsLEX

The aeros to the rear of something are also very important to achieving aerodynamic goodness.

Yep, my paint picture takes into account suction from behind the bikes, cause you'll notice that the lines directly behind the bike are far apart, this shows a low pressure zone, or a drag on the rear of the bike.

Also I know that there is a lot of disturbance and vortices in the air around motorbikes, but I was trying to show it as simplistically as possible in it's most useful form for motorbike racing, and my pics are from a combined accumulation of theoretical knowledge, and personal experience on the track, and also from cycling on the road.

**Sketchy_Racer** · 11th June 2006, 14:22

GAH!~!

TO MUCH BRAINY TALK!!!!!!!!!! shessh

**sAsLEX** · 11th June 2006, 15:03

Originally Posted by vtec

stuff

Just the text on your last written bit in the paint thingy metioned the front bike wasn't much affected by its rear aeros, just pointing out that the rear airflow is just as important as the front.

**Mr. Peanut** · 11th June 2006, 15:39

Here's some disturbing airflow

http://video.google.com/videoplay?do...73682011187743

**vtec** · 11th June 2006, 19:13

Originally Posted by sAsLEX

Just the text on your last written bit in the paint thingy metioned the front bike wasn't much affected by its rear aeros, just pointing out that the rear airflow is just as important as the front.

I didn't say that it wasn't affected at all, I just said that I was pretty sure the rear drag on the trailing bike was less than the frontal drag on the front bike...

In the last picture the front bike is not affected AS MUCH by it's rear aerodynamics, because it has a bike directly behind it keeping the air pressure quite neutral. There is still some drag from swirl effects and things, but a bike drafting behind you does help alleviate drag from behind the front bike. In NASCAR, the positive pressure in front of a trailing car is enough to lessen traction to the rear tyres of the car in front making it less stable... different things happen at different distances from the vehicle in front and at different speeds...