Motorcycle Aero Question

[Frank]

Another thread to read.....

Crosswinds are always an issue. I ran FoilSim (from NASA) to get a feeling of sideforce (lift) using ballpark numbers. It's not hard to develop a couple hundred pounds sideforce from very small crosswinds. I know about tests done with storm strips and would like to be able to try that concept out if needed.

This guy went 200 at Bonneville with a little over 100hp:
Tom Mellor Triump BMST 2016 by Frank, on Flickr

He spent a lot of time on the details. Wheelbase is extended and he used a very narrow swingarm/wheel combination which allows gentle curves. His front wheel is totally enclosed (not allowed by most sanctioning organizations) but I'm sure that helps too.

thanks,
Frank

[aerohead]

Kamm's asymmetrical wing section (much like a Clark-Y),with its aft section chopped off in 7 contiguous,equal-length segments registered a drag increase of:
*14%
*135%
*166%
*204%
*245%
*288%
*333%
--------------------------------------------------------------------------
Kamm's symmetrical airfoil,of 6-different aspect ratio configurations, created by shortening the aft portion,plus the airfoil,with no aft section at all registered:
*0%
*109%
*146%
*192%
*246%
*338%
*892%
--------------------------------------------------------------------------
Kosin and Lehmann's streamline body of revolution,chopped off in 10% increments registered drag increases of:
*0%
*3.03%
*12.12%
*28.8%
*59.1%
*200%
*256%
*330%
*425%
*567%
------------------------------------------------------------------------
These are just naked bodies,in free flight,with no wheels or anything else attached,but you can clearly see the drag penalty as the pressure drag builds from each successive truncation or shortening.

[sendler]

What is the ratio of the Kosin and Lehmann's streamline body of revolution? Is it exeptionally long? Why does it exhibit much better truncation performance?

[aerohead]

Originally Posted by sendler

What is the ratio of the Kosin and Lehmann's streamline body of revolution? Is it exeptionally long? Why does it exhibit much better truncation performance?

Their streamline body is 14.5:1 fineness ratio.(think fuselage)
As a streamline body of revolution, it has the best sectional density and pressure/velocity profile of all shapes,hence 'streamline' body.
No wing section can compete with a streamline body for drag on a frontal area-based comparison basis.They are quite literally 'ideal' in shape.

[Xist]

Frank and Aerohead, do you know what images you posted in #5 and on? Photobucket ate them!

[aerohead]

Originally Posted by Xist

Frank and Aerohead, do you know what images you posted in #5 and on? Photobucket ate them!

Mine were probably based on the symmetrical wing section table Freebeard was able to salvage.And the table I created from the FKFS research (Fachsenfeld and Kamm),and Hoerner's fairing tables.
I can't post any of them anymore.I've lost access to over 700-images and thousands of hours and dollars to create them since 2007.
Gotta love venture capitalists!

[freebeard]

One of these then?

[aerohead]

Originally Posted by freebeard

One of these then?

Yes,3rd from left on bottom row survives,but there were a couple I did later which only existed at PhotoBucket.

[freebeard]

Makin' it easy for the lurkers:

[Frank]

Originally Posted by Xist

Frank and Aerohead, do you know what images you posted in #5 and on? Photobucket ate them!

Mine was the same bike as in post #18 except an earlier version (pic in #5) had batteries in saddlebags. I found I wasn't using the range (100 miles) so redid the system and eliminated the saddlebag batteries. I can dig out a pic if you like but I'm not sure if it would be helpful.