Introduction & Cross wind solutions to motorcycle Streamliners?

[Grant-53]

Sorry, I'm an old road racing fan and I live just down the road from Watkins Glen. I watched Bruce McLaren race his first Formula I car there in 1966 Grand Prix. The term 'spoiler' could refer to more than one appendage. The tubing cross section used by Specialized looks like the airfoil in post #43 with 50% of the tail removed.

[JeffM]

Originally Posted by theo22

Hi teri,

Here's how a stormstrip on a Quest velomobile looks like

The theory is (probably known but anyway) that air that flows sideways will become turbulent flowing over the stormstrip. And turbulant air can follow the shape longer, creation less underpressure and thus less sideforce on the vehicle.
Since a velomobile is a very light vehicle (35 Kg) with a relative big side-surface it is even more sensitive to sidewind than motorcycles.
I got blown off the road ones in a storm and use this strip since.
My 125cc Honda will get a strip too.

Craig Vetter uses a storm strip (aero fence) on his stream-liner and recommended I do the same on mine to reduce crosswind instability.

[PeterS]

Jeff, where abouts on yours ? I can make it out .

[doviatt]

The thing that looks like a vertical parting line. Look low on the nose as it sweeps away underneath. You can see it contrast against the bricks.

[PeterS]

OK, silly me, I thought it was part of the structural joint.

[Teri_TX]

Hi Peter,

Originally Posted by PeterS

OK, silly me, I thought it was part of the structural joint.

The "storm strip" on Theo's Quest is only about 18mm on a side of the triangular section from reading the rough Google translation of the original pages. The original trial appeared to be a piece of insulation gasket material with the adhesive tape. It's not clear if the Dutch experimenters tried various heights or not. I wonder if a higher section MIGHT be more effective (but more unaesthetic).

Vetter's fence on the tail of his streamliner is 1" (per Vetter) high. It looks to be a piece of 1" aluminum flat stock from the local home center.

As I had said earlier, I wish I had a streamliner to experiment on.

-- Teri

[P-hack]

experiment being the key word, as such a fence increases side area as well, farthest from the wheels(pivot).

[sendler]

Originally Posted by JeffM

Craig Vetter uses a storm strip (aero fence) on his stream-liner

That is brand new. I have ridden with Craig for two years and never saw that strip. Any storm strip would have to run up the nose because the point of max lift of a wing is toward the max thickness. Which he has already taken care of by venting any pressure differential through the leg opening. That rear placement would be some kind of different concept and seems like it is spoiling the wrong end if he wants to have a long tail in the first place. I saw another attempt at a streamliner which had a similar knife edge along the top of the tail and it was prone to oscillation. At which point the aero experts here recommended that a rounded top would be the way to go.
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The vented streamliners are exceptional in crosswinds already as they are. No need to change them unless you try to fully enclose them. Riding behind Alan on the highway, the stability of his Vetter streamliner in rough truck wakes is uncanny. The bike is invisible to the wind. The Hayes diesel bike with the land speed bodywork was all over the road.

[sendler]

Motorcycles are naturally self correcting in cross winds due to trail in the front end as was discussed in the "windy, slippery, slope" thread and is demonstrated by the video of the ecotracer. Which would make the same correction to the abrupt side wind blast with no hands.
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http://ecomodder.com/forum/285297-post137.html
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It helps to keep the cg on the roll axis high and the side center of pressure lower.

[Michael Moore]

Originally Posted by P-hack

80mpg@80mph isn't too shabby, but an 850cc engine should be able to go a lot faster than 125mph even on a naked bike, . . .

FWIW, the 850cc Reliant engine used in the Voyagers is probably making about 40 hp on a good day. Don't try to compare it to a modern (or even 35 year old) motorcycle engine for power.

cheers,
Michael