Vetter streamliner body kit

[PeterS]

Hmmm, this is a bit difficult and I'm glad to be educated . My understanding is that a standard sit up and beg motorcycle is around .9. That works out perfectly with the calculator and a 1955 13hp Royal Enfield on test. It was using it's maximum hp and it's power and fuel consumption were very accurately recorded.

Can you link me to some site giving the cd of various bikes ? Perhaps some allowance for the rider sticking up on top? The rider must get the .9 cd surely ?

What do you think Craig's model would rate ? .35 ?

[sendler]

Originally Posted by PeterS

Hmmm, this is a bit difficult and I'm glad to be educated . My understanding is that a standard sit up and beg motorcycle is around .9. That works out perfectly with the calculator and a 1955 13hp Royal Enfield on test. It was using it's maximum hp and it's power and fuel consumption were very accurately recorded.

Can you link me to some site giving the cd of various bikes ? Perhaps some allowance for the rider sticking up on top? The rider must get the .9 cd surely ?

What do you think Craig's model would rate ? .35 ?

The Hayabusa is supposedly the lowest cd of any production motorcycle. At .55cd. Pretty bad still. Cars can get into the .20's. But there are some smaller class race bikes that are pretty clean so would have less cda than the Busa. Craig's concept? Alan just added a clear shroud to clean up the license plate area behind the rider's head and is playing with partial "doors" to see how clean the sides can be while still maintaining enough opening to vent the maximum pressure differential of the sideways wing shape that eliminates crosswind issues, and to let his feet to touch down. cd of .20?

[bschloop]

I think somewhere between .30, and .35 is a pretty good approximation for craig's bike. this is basically a blunt somewhat smooth body with good profile. the open sides act like open windows or wheel wells on a car. only creating a deceptively small amount of turbulence. Allert's would probably fall between .25, and .30, and looks to be quite a bit lighter. Also rolling resistance would be just over half the average for a car. this accounts for higher resistance tires, but half the number of tires. you must also figure that we are not using 100% of our rated output at 70mph. why? we could ride 70 all day without killing our bikes. 100% output will damage an engine after a relatively short period. The most efficient design would use about 60-70% load with the lowest drag possible. also, my bike is rated at 12-14hp new and is 30 years old. I was probably using closer to 10hp on the 70-80mph section, and making it up on the slower parts using closer to 5-6 hp. Craig's bike is rated at 16hp, and could go 70-80mph. this means that either the calculator is wrong, or that Craig's design is better than you give him credit for.

For the record, my frontal area was quite a bit less, but I think my cd is slightly higher.

[sendler]

Yes. Craig's bike is not a small bike but he wants it to be also very comfortable and useful. He already built a minimal bullet fairing that can get 400 mpgUS 30 years ago but it is of no use.

[cvetter]

I confess. I have always been suspicious of people who do quick calculations to give me a number. Do their numbers account for winds? Blasts coming from the front? From the side driving on wet wire mesh bridges? Do they account for Peterbilts passing in either direction in ferocious winds? Climbing mountains? Do numbers account for riding comfort? Staying dry in the rain? Ease of use? Etc. etc.

Of course we could go on and on.

I would rather design, build, ride and learn. I would rather fix what is wrong and ride some more. Eventually, the problems to fix are pretty minor. That is where the Last Vetter Fairing is now.

In the Vetter Challenges, we are learning that while my 16 hp Honda Helix has the power, it runs at the edge of its ability at 75 mph, into powerful headwinds, up hills. It wears out too quickly. It is working too hard. On the other hand, the Ninja 250s in the Challenge easily cross America to the Challenges and when they get there, consume less fuel than my Helix.

If I were to start over, it would be with a Ninja 250. We learn these things on the road, not from charts.

If somebody had a well thought out kit for streamlining, I'd buy it in a heartbeat. I save my efforts for things I cannot buy.

Certainly I understand that shipping to Australia will eat you up and you are probably forced to make your own streamlining. Study what I have done. There is a reason for every line. See if you can better.

It would be informative to post a rough number of hours spent on making your own nose.

Craig

By the way... my figlass guy charges me $500 for the 2 nose kit. I am not doubling this at $750 because the parts are not as perfect as I would like. At $750, per nose kit, I think they represent a bargain.

[PeterS]

Originally Posted by bschloop

I think somewhere between .30, and .35 is a pretty good approximation for craig's bike. this is basically a blunt somewhat smooth body with good profile. the open sides act like open windows or wheel wells on a car. only creating a deceptively small amount of turbulence. Allert's would probably fall between .25, and .30, and looks to be quite a bit lighter. Also rolling resistance would be just over half the average for a car. this accounts for higher resistance tires, but half the number of tires. you must also figure that we are not using 100% of our rated output at 70mph. why? we could ride 70 all day without killing our bikes. 100% output will damage an engine after a relatively short period. The most efficient design would use about 60-70% load with the lowest drag possible. also, my bike is rated at 12-14hp new and is 30 years old. I was probably using closer to 10hp on the 70-80mph section, and making it up on the slower parts using closer to 5-6 hp. Craig's bike is rated at 16hp, and could go 70-80mph. this means that either the calculator is wrong, or that Craig's design is better than you give him credit for.

For the record, my frontal area was quite a bit less, but I think my cd is slightly higher.

OK, this is good. It's always been hard to get any even faintly definitive figures for bikes and of course the problem isn't the bike fairing but the big pimple of a rider sticking out the top of a good looking fairing like the 'Busa. Craig's design solves that although it is possible I'll have to have the rear sections on 2 heavy duty drawer slides to let me get on easily... unless I can get the seat low enough.

Craig, I'll copy very closely but it will be going onto a Royal Enfield fitted with a diesel engine. Diesel will let me burn biodiesel too, the ultimate efficiency. It has to be an Enfield because unless the bike is pre 1970 our local rego boys won't let me modify it.

Calculators ? I'm an engineering kind of bloke and being able to see where the power goes is interesting, it lets me see where the effort is needed.

[cvetter]

What kind of horsepower does the Enfield Diesel put out? It seems that you would need closer to 25 to operate in "Vetter Conditions" with any kind of longevity. Does anybody really know what kind of horsepower my Helix is putting out at 7-8000 rpm?
We seem to be guessing at 16. All I know is that I am working the Helix engine too hard. The compression is now below spec. It blows head gaskets. If I continue running at 70 into headwinds, etc, etc, I will probably continue hurting it.

The scooter configuration is best.

With a scooter, you don't have to put the bodywork on sliders to get on easily. You just walk over, sit down and drive away. You don't have to throw your leg over a high seat.

Diesels are hard to beat because they consume 3/8 lbs of Diesel per horsepower per hour while gas motors burn up 1/2 lb of fuel per hp per hour.


That said, the Ninja 250 seems to offer the best gas motor fuel consumption when you factor in engine life.

Some Vetter Challengers are looking into "alligatoring" their Ninja frames to get the seat height down.

2013 should offer some real excitement at the Vetter Challenges as we home in on the right formula.

[PeterS]

The little 10 hp diesels that are easy to fit to the Enfield are really 9 hp so using 75% power (6.5 hp) gives a cruising speed of 65 mph. That is plugging in a cd of .35 for a Craig style fairing as you suggest. That would be entirely adequate for my use and allow freeway travel.

I'm not allowing for headwinds, much more than 10 mph would see me on a side road but still OK. The calculator gives the mpg as US 126 at 65 mph. If it's biodiesel I only pay for 25% of it, it's cheap!

Making of the 10HP Diesel Prime Mover - ADVrider

Looking good !

[PeterS]

I can't use a feet forward "scooter" arrangement. To do any serious mods here the bike has to be older than 1970 and the early scooters are crap.

[stiletto2]

I came across a posting in another forum referencing this site and it dawned on me that I have been signed up here for over a year... Just kind of forgot it but I'm back now because of the Vetter streamliner fairing. Which I will have the nose pieces for soon.

I'll get this project under way on a Honda Reflex scooter I have. Just a slightly larger engine (249cc) VS the Helix (244cc) and what ever increase in HP that brings. With bigger wheels on the Reflex with (12"-R, 13"-F) and the Helix with (10"-R, 12"-F), I am able to use tires larger than the standard Reflex tires. Plus a small step up in the final drive ratio with a gear set made for racing, I should be able to go at given speeds at lower RPMs. Lower RPMs = less fuel used and less engine stress. Especially when combined with streamlining to make it easier to do so.

Depending how quickly the project goes, I'm seriously thinking of starting another Vetter streamliner even before the first one is done. I already have a small handful of Reflex scooters to work with plus a Honda FSC600A Silverwing. (I really do like my Reflex scooters best though)

Like others here, I was surprised at the the original cost estimate at first but understand nothing is really cheap anymore for numerous reasons. But that is not going to hinder me. Especially now since it is just the nose which would be the hardest piece to dIY and it is at a much more affordable price. Craig has done all the ground work to make it easier for the DIYer. Got some more reading/research to do to increase my chances of success with FG though. But it should be alright.

Speaking of FG, I wonder how stiff/flexible just a couple layers of light FG with maybe a layer of thin Kevlar laid up on a big sheet of glass (door wall glass), would wrap around for the back of the fairing. I suppose stiffeners could be laid in on the inner surface to help give it rigidity once it is attached to the bulkheads. Done right I think, it could be taken off and rolled up somewhat. Using Kevlar, it might be able to withstand some abuse as well and would be relatively easy to repair if needed. After experimenting some I may try that. Got some CF too off ebay once upon a time, but that may be too rigid to flat wrap and would probably need to be put into a suitably shaped form.....Nah, more trouble than it's worth.

Think I'm going to use one of those really neat electronic gauges like ones from KOSO NorthAmerica...... I've got ideas.... but that is part of the whole point of this. Experiment, build, ride (my favorite part) and merely sip gas when riding. I'm stoked!