Streamliner Fairing For Free

[3-Wheeler]

Hi,

What you see below is the result of two years of gluing foam blocks together, sanding, shaping, and finally, glassing with epoxy and fiber glass cloth.

It's been ridden on the bike for about one month now, and works great, except for one thing that bothers me enough to consider selling it.

Data:

The fairing is currently fitted to a 2012 Honda CBR250R. The fairing is held onto the motorcycle with a custom tubular frame, that took two iterations to get right. Just creating the framework took an entire winter with the motorcycle in the basement.

The next winter saw about 1-1/2 sheets of 1.5 inch foam to complete the fairing shape in the same theme as Craig Vetter would do.

The fairing is very robust with minimal flex from wind and so on. It currently weighs 18 lb and has a full layer of 6 ounce glass both inside and out. The outside is currently sanded fairly smooth and the inside is not sanded at all.

Gas Mileage:

The stock gas mileage of the CBR is so far 115 mpg, driven mostly around 45 mph on country back roads. The same when done with the streamliner fairing yields about 122 mpg. This is calculated after four full tanks.

Construction Quality:

I consider this a top quality build. Details: each fastener has a brass hole liner that acts as a torque limiter, to prevent any damage to the embedded wood blocks. My last fairing had fasteners directly loading the wood, and it took a set over many years of use. The brass liner also intends to keep moisture out of the wood block, for better longevity.

I used West System Epoxy for all glass work, and a gram scale for all mixing of epoxy and hardener. Yes, I could have used pumps, and have in the past, but as of late, the pumps stopped working, so break out the scale.

There are welded embedded fixtures inside the fairing foam that hold the mirrors in place. Unless the bike is tipped over, these mirrors are not going to move at all.

The plexiglas is high quality Lexan. It is pre-bent to it's current shape by placing in a custom fixture, and holding at 130C for 4 hours. The plexi is allowed to cool, then band sawed to it's current shape, edge sanded, drilled for mounting and fastened to the fairing mounting holes. By the way, the Lexan can be bent over on itself about 180 degrees with no flex failure. As long as the owner does not scratch the glass, it should last the lifetime of the fairing.

The fairing shape around the handlebars is about 1 inch larger than the swing of the handlebars. The handlebars are custom welded units that were narrowed for the minimum width to the wind. The stock handlebars will not fit inside this fairing.

Reason for Giving Away:

Side winds. Craig and others may be less sensitive to side winds, but riding in a 20 mph side wind makes me very unsettled. I can do, but simply do not care to continue riding with this much side wind sensitivity, thus the sale.

I have full plans on making yet another streamliner, but with much less side wind sensitivity.

Price:

Free











Thanks for looking, Jim.

[sendler]

What do you think you will do differently next time?

[JockoT]

"Dustbin fairings" were banned from racing bikes, in the late 50's, because of safety concerns in side winds.

[Michael Moore]

JockoT, the Guzzi fairings didn't have problems, having been developed with a wind tunnel (full size) by people who had a clue about what they were doing. It was largely the garden shed copiers who made slab-sided fairings that looked somewhat similar who had problems. The FIM was also going through a "racing is getting too expensive/fast phase" as they did in the mid 1960s. Guzzi had no plans to drop the dustbins as they weren't causing them problems.

Jim, you've clearly put a lot of work into your fairing and $500 is not going to come close to covering your time. I like the fairing mount structure. I'm wondering if your side wind problem may be due in part to the center of pressure being moved forward (more than on the standard bike) so it is now in front of the center of gravity? I note that the Guzzi fairing stagnation point is significantly higher, your's looks more like a small MV Agusta fairing. Perhaps you could resolve some of the side wind issues by adding some rear bodywork?

ETA: http://ecomodder.com/forum/showthrea...tml#post419219

That 1955 Isle of Man test of the Guzzi and Norton 350s had Vic W. saying of the Guzzi "occasionally there was mild disturbance from a side wind, but must less than I expected -- thanks no doubt to the low build of the dustbin and the curvature of its flanks. Certainly its benefits in speed, fuel economy, comfort and protection seemed greatly to outweigh any drawbacks." while about the Norton with the DIY fairing ". . . the high flat fairing caught appreciably more wind."

cheers,
Michael

[3-Wheeler]

Originally Posted by sendler

What do you think you will do differently next time?

Well, two things.

I want to reduce the side area to reduce the side wind tendency.
Two, I want to make a much smaller fairing to reduce the weight.

It's probably going to end up looking very similar to a fairing I made 30 years ago for the VF500 Interceptor.

As for details, I don't want to disclose them right now, as I may still be barking up the wrong tree. Think of the blind leading... well you know. We shall see by next spring.

It looks like the tail won't go on until the spring of 2019.

Edit: tell you what, I might as well post the entire build so that we have a good discussion point going forward. Disclaimer: I don't check the site that often this time of year with projects around the house going on, like new counter tops going in this fall, so please be patient. There are a couple areas of the new fairing shape that might make for some interesting discourse.

My main goal in posting the sale of the existing fairing is give someone the chance to get into a streamliner without too much work, and they can decide for themselves how it works for them. If there are no takers, then it will be completely changed by next spring, but I do feel better knowing that others had the chance to benefit from the initial effort.

[3-Wheeler]

Originally Posted by Michael Moore

JockoT, the Guzzi fairings didn't have problems, having been developed with a wind tunnel (full size) by people who had a clue about what they were doing. It was largely the garden shed copiers who made slab-sided fairings that looked somewhat similar who had problems. The FIM was also going through a "racing is getting too expensive/fast phase" as they did in the mid 1960s. Guzzi had no plans to drop the dustbins as they weren't causing them problems.

I think that Craig had the same problem as his wife Carol was shocked at how much his streamliner moved around while she was following him. I also think that side area is still side area regardless of the shape, within reason.

Originally Posted by Michael Moore

Jim, you've clearly put a lot of work into your fairing and $500 is not going to come close to covering your time. I like the fairing mount structure. I'm wondering if your side wind problem may be due in part to the center of pressure being moved forward (more than on the standard bike) so it is now in front of the center of gravity? I note that the Guzzi fairing stagnation point is significantly higher, your's looks more like a small MV Agusta fairing. Perhaps you could resolve some of the side wind issues by adding some rear bodywork?

Yes, I think that the center of pressure is in front of the center of mass. And yes, I think that adding a tail could move it backwards, but still think that on a rainy day with limited traction, it could get dicey with large winds blowing, so the fairing on my bike to going to get modified quite a bit. It's a big experiment!

I am looking for 1) Aero, 2) Coverage, 3) Light Weight, 4) Low side wind sensitivity. It makes sense to me to keep the side wind sensitivity low with just the front portion, so that when the tail is added, it does not go much higher.

To accomplish this, it looks like two-thirds of the existing fairing will be discarded.

Jim.

[sendler]

Much discussion and reasearch has been done regarding sidewinds and streamliners if I can find some of the pertinent threads. Keep in mind that it is only a side wind when you are parked. When traveling on the highway, a 20 mph side wind combines with the 60 mph headwind to appear as one wind vector coming at an angle just off the nose. Which means your airfoil has an angle of attack to make lift if you have good attachment.
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Motorcycles automatically lean into sidewinds due to the trail in the steering geometry if nothing else gets in the way.
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Honda CBR250R Forum : Honda CBR 250 Forums - View Single Post - Cross Winds
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I read and interesting test by some HPV designers who tied a string to a bike in various places to to ride along next to it in another vehicle to try to pull it to the side. Pulling against the rear rack was easiest to pull it over. Pulling against the seat post was second easiest. pulling against the head tube was very difficult to upset the bike since it automatically leaned away from the pulling.
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The maximum lift (side) from a streamlined faring needs to be no further back than the the head tube. A bike is not a dart in the air. It has two wheels hooked to the ground. And it doesn't turn from steering. It turns from counter steering and then leaning. So the idea of a long tail acting through the rear wheel like a fulcrum (or the cg) and turning the nose into the wind is flawed since this would create a counter steering force through the front wheel that is hooked to the ground that would initiate the bike to counter steer, lean, and turn the wrong way. WITH the wind.
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I have ridden behind the Vetter bikes many times and the tail seems to be a non issue either way. Their bikes respond to cross winds about the same as mine. Which is about the same as stock. Although there is no debating the fact that a full tail is more aero than a truncated one and they do seem more imune to shaking in the dirty air of truck wakes.
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Venting across the design at the point of max lift has been the key. Craig tried a door on his bike and took it off because of poor crosswind performance. Judging by the air rushing across my legs on my PCX in crosswinds I would say it takes circa 2 sq. ft. of area.
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Foilers. You will notice that all of the modern sport bikes tend to have a sharp point protruding on either side of the headlight. It is areo when head on. but will spoil the far side attachment in a side wind.
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[Michael Moore]

The stall strips give what is called a "soft stall", basically a more gradual loss of lift.

[3-Wheeler]

Hi,

I sold the 2012 Honda CBR250, and no longer need the streamliner fairing, so I am looking for a new home for it.

The free items include the entire tubular mounting system and foam/fiberglass fairing.

The two pictures below show the overall dimensions of the fairing.

P.S. I will be making another fairing for different motorcycle.

Jim.

[3-Wheeler]

Hi,

Just wanted to give a heads up that the fairing will be dismantled at the end of October, along with the mounting system, if there are no takers.

Jim.