101.5 MPG on my 2003 Ninja 250!!!

[beatr911]

Nice post. Thanks.

Also please keep us up on the aero fairing. This is where I want to go on the next bike I buy (prolly a ninjette) and there appears to be interest in a subculture of ninja 250 mileage geeks. Not sure of your plans for the fairing, such as if you plan on manufacturing or marketing it, but I'll stand up as interested in buying a copy.

Related recommendation: Rent the movie "The worlds fastest Indian". Motorcycles, speed records, a really good story to get you inspired to do what they say can't be done.

[theycallmeebryan]

Originally Posted by beatr911

Nice post. Thanks.

Also please keep us up on the aero fairing. This is where I want to go on the next bike I buy (prolly a ninjette) and there appears to be interest in a subculture of ninja 250 mileage geeks. Not sure of your plans for the fairing, such as if you plan on manufacturing or marketing it, but I'll stand up as interested in buying a copy.

Related recommendation: Rent the movie "The worlds fastest Indian". Motorcycles, speed records, a really good story to get you inspired to do what they say can't be done.

If i do actually go ahead with it, ill be starting sometime in the winter when its snowing and i can't ride my bike. At this time, i have no plans of manufacturing the fairing as I'm a 22yr old college student and I'll be doing this in my garage by hand. It takes a lot of labor hours to make a fairing like this.

I had a friend make my a quick 3d mockup in 3DS Max of what the fairing could look like. It follows the NACA 67-025 foil shape and tapers rearward as you go up the fairing. Also, the top is also the same foil laid on its side, and then tapers smoothly to meet the rest of the fairing. So heres a visual:

This is the NACA 67-025 foil.


Front


Rear


The fairing will be about 10 feet long and 2.5 feet wide. It will be made entirely of fiberglass because i have worked with it before and already know the tricks. I'm thinking the top bubble i could make entirely of lexan or something similar, which would allow me a full 360* of view. As for getting in an out of the fairing, i plan on making a door on a hinge from the left side of the bike with a push release latch (like some cabinet doors are).

[Christ]

Originally Posted by theycallmeebryan

If i do actually go ahead with it, ill be starting sometime in the winter when its snowing and i can't ride my bike. At this time, i have no plans of manufacturing the fairing as I'm a 22yr old college student and I'll be doing this in my garage by hand. It takes a lot of labor hours to make a fairing like this.

I had a friend make my a quick 3d mockup in 3DS Max of what the fairing could look like. It follows the NACA 67-025 foil shape and tapers rearward as you go up the fairing. Also, the top is also the same foil laid on its side, and then tapers smoothly to meet the rest of the fairing. So heres a visual:

This is the NACA 67-025 foil.


Front


Rear


The fairing will be about 10 feet long and 2.5 feet wide. It will be made entirely of fiberglass because i have worked with it before and already know the tricks. I'm thinking the top bubble i could make entirely of lexan or something similar, which would allow me a full 360* of view. As for getting in an out of the fairing, i plan on making a door on a hinge from the left side of the bike with a push release latch (like some cabinet doors are).

So what happens when you dump the bike? Have you considered the greenhouse effect that will occur with a lexan upper "bubble"? Could get pretty hot in there without any ventilation, ya know?

Why not look at the recumbent thing that Craig Vetter did with his little moped thingy? (Sounds pretty specific, doesn't it?)

[dcb]

Originally Posted by Christ

So what happens when you dump the bike?

C'mon dude, what do you think happens?!? It's better than flesh on pavement anyway.

Think positively

[Christ]

Originally Posted by dcb

C'mon dude, what do you think happens?!? It's better than flesh on pavement anyway.

Think personal safety...

Fixed.

I'm thinking it's a positive project, but "thinking positively" is subjective at best. Sure, it's positive in that he can get like 30% better gas mileage, but in the (however unlikely) event that something goes wrong, he's stuck in a (possibly burning) cage of fiberglass. I don't think the perceived risk is worth the gains, by any means.

Referring to Vetter's design, there is adequate room for escape, and you won't even get rashed up for the most part, because the legs are protected by a streamlined (but still open) fairing.

[Christ]

RE: Vetter Fairing:

[theycallmeebryan]

Originally Posted by Christ

So what happens when you dump the bike? Have you considered the greenhouse effect that will occur with a lexan upper "bubble"? Could get pretty hot in there without any ventilation, ya know?

Why not look at the recumbent thing that Craig Vetter did with his little moped thingy? (Sounds pretty specific, doesn't it?)

I dont ever plan on dumping the bike. But i understand what you are saying. What if i dump the bike and there is no way for me to get the bike upright? I'll just be laying in the road like a fish out of water . I surely will design the fairing to accommodate that.

As far as getting hot, thats where NACA vent's come into play. They aerodynamically draw air into the shell without significantly effecting overall drag. You see them on a lot of airplanes and race cars. I probably will make the bubble removable for blistering hot days.

I think by recumbent you mean sitting leaning back a little? Craig's streamliner was a Honda Helix 250 scooter, and he designed his fairing around a fish shape. I am taking a similar approach. The main difference is that craigs bike was a scooter and mine is a sport bike, so the fairings are going to look a bit different because of the different seating arrangements.

[Christ]

Originally Posted by theycallmeebryan

I dont ever plan on dumping the bike. But i understand what you are saying. What if i dump the bike and there is no way for me to get the bike upright? I'll just be laying in the road like a fish out of water . I surely will design the fairing to accommodate that.

As far as getting hot, thats where NACA vent's come into play. They aerodynamically draw air into the shell without significantly effecting overall drag. You see them on a lot of airplanes and race cars. I probably will make the bubble removable for blistering hot days.

I think by recumbent you mean sitting leaning back a little? Craig's streamliner was a Honda Helix 250 scooter, and he designed his fairing around a fish shape. I am taking a similar approach. The main difference is that craigs bike was a scooter and mine is a sport bike, so the fairings are going to look a bit different because of the different seating arrangements.

The one posted above is actually a Kawasaki KX250, single cylinder 4 stroke.

The seating position was re-configured from straight up to recumbent (leaned back, la-z-boy style.

The fairing could look quite different, I agree. I've also seen many fully enclosed designs, such as Burt's Bonneville fairing (Fastest Indian), except he used part of his body as the upper part of the fairing, seated in sport-bike configuration, so that while tucked, he was the upper line of the fairing, and the bike could still be ridden somewhat upright as well.

Just shooting some ideas out there for you, so you don't overlook anything, and maybe you'll find/solve a problem with something. Here's to safety and good luck with the design!

[theycallmeebryan]

Originally Posted by Christ

The one posted above is actually a Kawasaki KX250, single cylinder 4 stroke.

The seating position was re-configured from straight up to recumbent (leaned back, la-z-boy style.

The fairing could look quite different, I agree. I've also seen many fully enclosed designs, such as Burt's Bonneville fairing (Fastest Indian), except he used part of his body as the upper part of the fairing, seated in sport-bike configuration, so that while tucked, he was the upper line of the fairing, and the bike could still be ridden somewhat upright as well.

Just shooting some ideas out there for you, so you don't overlook anything, and maybe you'll find/solve a problem with something. Here's to safety and good luck with the design!

It seems like there would be an awful lot of turbulence around his legs in their configuration. I wonder why the fairing on this bike wasn't designed like this, where he could drop his feet downward to meet the opening.


I've seen burts Indian quite alot, and my original plan was to make a fairing with a tucked position in mind... just like the rifle on craig's website.


However, after i began having lower back pains for constantly tucking every day, i decided to rethink that idea. In fact, i look just like the guy in the picture above when i tuck. Imagine sitting like that for an hour straight.

Just like Craig said, i want the vehicle to be comfortable and practical for every day use.

[Christ]

I read up on Burt's design and several similar ones awhile back, and the consensus was that while tucking, you should place your elbows on your knees, which relieves stress on the back and places it in "load bearing" areas of the body.

Vetter wanted to make it a "step in" design, in case he needed to "step out" quickly. It's easier to move in one fluid motion (outward and down) than to move in a direction, then change directions abruptly, especially when human nature says you'll widen your stance and extend your legs during a panic situation, rather than retract them and push outward and down.

I doubt psychology crossed Vetter's mind when building that bike, but that's how it works anyway.

What about building a fairing and rider's clothes combo, where the legs of your outfit fill in the gap where your legs go in the fairing? They could be as simple as some plastic bits that strap onto your legs, and can be removed with velcro (like Reeboks, man!)