Silly idea 14B

[Sibbo]

I've always had an interest in high mpg vehicles ,motorcycles and recently ,biodiesel .

I've decided to combine all these interests into one project ,a diesel ,aerofaired bike running on biodiesel .The basis will very likely be an Indian Enfield Bullet fitted with a huge and powerful 10 hp Chinese aircooled diesel In that condition the ''performance'' would be slightly less than abysmal.The only way to improve that situation is to reduce the drag ,that invisible hand that eats approximately 90% of most normal motorcycles .

These diesel bikes normally get 130 mpg US or around 1.8l/100km .A fairing like the one I've designed should achieve around 1.3 l/100km 180mpg US at say, 45mph .A maximum speed of 70mph /110 km .

http://ecomodder.com/forum/tool-aero-ro ... stance.php

It's going to be an interesting project ...lots of small details but the main project seems doable .If anyone is interested I'll expand on the ideas .

[Major Softie]

The only way to improve that situation is to reduce the drag ,that invisible hand that eats approximately 90% of most normal motorcycles .

I knew that drag was eating my fuel, but I didn't know it was eating my whole motorcycle!


Sounds like a very fun project. Streamliners always have some major problems that you have to solve: side-winds, how to get on/in, and how to put your feet down. I've seen a few different solutions to the 2nd and 3rd, but never a really good answer to the 1st. Be interesting to see how your ideas work out.

[Sibbo]

Side winds are the problem .The normal response these days is to have more area aft of the centre of pressures ,that turns you up into the wind .

The problem I'm having trouble with is the generated side lift from wind off the nose , say 15 degrees .I may be able to solve that by having the fairing remain slightly open and so spoil the differential pressures between the sides .

[Chuey]

Laying the rider down a bit would possibly help.

Chuey

[Sibbo]

Leaning forward is good at 70mph with the wind on your chest ,in this case there will be no wind on my chest and the weight would all be on my arms .I want to be able to do 10 hour days on this and do a 3000 km tour with fuel I can carry on the bike .

[Major Softie]

Leaning forward is good at 70mph with the wind on your chest ,in this case there will be no wind on my chest and the weight would all be on my arms .I want to be able to do 10 hour days on this and do a 3000 km tour with fuel I can carry on the bike .

Which can still equal low positioning, if we talk recumbent (like the bicycles) or leaned forward with chest resting on something. Recumbent is much more comfortable, but both lose the high eye perspective we all enjoy.

High and tall simply isn't as effective at avoiding wind resistance as low. It's not just the reduction in frontal area, it's an even greater reduction in side area.

[Sibbo]

Leaning forward is good at 70mph with the wind on your chest ,in this case there will be no wind on my chest and the weight would all be on my arms .I want to be able to do 10 hour days on this and do a 3000 km tour with fuel I can carry on the bike .

Which can still equal low positioning, if we talk recumbent (like the bicycles) or leaned forward with chest resting on something. Recumbent is much more comfortable, but both lose the high eye perspective we all enjoy.

High and tall simply isn't as effective at avoiding wind resistance as low. It's not just the reduction in frontal area, it's an even greater reduction in side area.

You're right of course , the height of the fairing is a real disadvantage aerodynamically, it does however have one advantage and that is visibility, both for me and of me .The frontal area disadvantage is directly proportional to the area ..... but with the disadvantage of the added area being up high .

This chap has built quite an amazing machine based on a Honda 125 .It gets over 230mpg US and will do 80mph .No problems with 40 mph side winds .It's a truly remarkable bit of home engineering .



http://www.velomobiel.nl/allert/Recumbe ... orbike.htm

Unfortunately I can't copy him directly ,attractive as the idea is .He has set up a feet forward riding opposition and dropped himself down quite a way . Such mods are illegal here,no frame modifications or to the basic factory layout ..... so I have to just apply a fairing to a standard bike .

[Garnet]

Here's half the solution. Costs money though.

http://www.airtech-streamlining.com/gil ... 251958.htm

Edit and this one for yer airhead:

http://www.boxercafe.com/fairfulldust.htm

[Sibbo]

Yep ,half a solution .Dustbins were banned at a very early stage of development ,the fairing being mainly forward causes a few problems in sidewinds ..... they fall over .All the modern developments fair the rear of the bike first !Except under racing rules which won't allow a decent fairing . Strangely enough it how a body exits the air rather than how it enters that is more important.

I'd chase one of those up is they were closer though, but just for the ST.

[vanzen]

Side winds are the problem .The normal response these days is to have more area aft of the centre of pressures ,that turns you up into the wind .

Quite correct ! Location of the Centre of Pressure sill be the key to stability.

...The problem I'm having trouble with is the generated side lift from wind off the nose...

BMW's solution to was to design a fairing that created downforce.
Angled surfaces on the top and sides of the fairing and
a concave - hollow portion on the underside around the forks tubes.

Of course you are tuned into Craig Vetter's work in aerodynamics & MPG ?

COOL project – hope to hear more as it progresses.