Aerobike side wind testing crash

AeroBike's picture

I have finally got back to working on the Aerobike but testing did not go well-
I had been waiting for some reasonably strong winds and we got them today in my area, so with my neighbour following, I headed down the road to evaluate the side wind behavour of the bike.

Going south with the wind blowing mostly from the tail and side the bike felt fine, pushed around a little bit but no worries about staying in my lane or losing control, so all seemed good.

I then turned around and headed back with the wind coming onto the left front of the bike, (I would guess it was blowing about 20-30 knots).

I had only travelled about a kilometer (at about 75 km/hr ) to where the road has large trees on both sides (open understory but dense foaliage above) when the bike was hit by the wind. The bike seemed to automaticlly respond by leaning into the wind (probably only about 10 degrees), it seemed to be in this steady state for maybe 2 or 3 seconds, but I had the feeling that falling to the left was inevatable.....I think this was due to there not being any torque on the handle bars that you get on a conventional motorbike in a side wind....

I think I got a bit scared and did something, not sure if I steered a bit to the left to maybe even to the right ( definately the wrong thing to do!!) but anyway, ended up with the bike sliding down the road and into a ditch (luckily fairly smooth and deep enough to keep me away from the trees!!).

The bike came to rest fully over on the left side so I had to pop out the door section of the canopy to get out (I hadn't finished the door catch release to enable the door to be opened in this situation).

I was uninjured but the bike suffered a broken mirror, quite a bit of fibreglass damage and canopy scratches....I don't think there is any structural damage though...

I think the bike, with the wind blowing in this direction acted like a wing, and sucked the bike into the wind (leaning into the wind ) . I am not sure if I had not got scared and tried steering, whether the bike would have corrected itself ??

Thinking on this though, if the wind had suddenly died,with the bike leaning to the left, this would have caused the bike to turn to the left, this behavour would of course be too dangerous to continue with....

I have read that the Monotracer automaticly leans into the wind to compensate but does it automaticly bring itself back to vertical if the wind suddenly drops?

Any help with this would be greatly appreciated....

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Ian's picture

Voyagers in the wind

The vid you are looking for Royce is this one.

AeroBike's picture

thanks, they seemed all right

thanks, they seemed all right in the wind, I think it would still be rather un-nerving....


"Edge of known space"

I hope you haven't found your crash too discouraging. You are 'over the edge of known space' with your bike and the lessons you learn, the problems you identify, will add to the growing knowledge of PTW aerodynamics.

I believe that considerable work remains to be done on 'full enclosure' FFs. The Eco/Montracers are at the stable end of this class due to their great size and length, although I believe several owners have expressed concerns about their sidewind performance. Your vehicle is shorter and ligher and may be taller. These all tend to reduce stability and indifference.

It follows that extra care and attention must be paid to sidewind stability when designing shapes like yours. You may be encouraged by the very good stability achieved on open-cockpit FFs. These have shown that simple details can largely eliminate sidewind problems, so similar attention to side area, separation, etc. should also work on larger shapes.

It may be more of a problem to minimise sidewind effects at low speed. The vehicle has less dynamic stability and urban gusts from side streets may be quite strong and sudden. The bodywork needed to cover a human being cannot be reduced beyond some point and low vehicle weight, coupled with low speed, may eventualy cause excessive sensitivity to sidewinds. I expect this to be a problem for HPVs rather than PTWs but care will definitly be needed to develop a fully satisfactory enclosed bodyshape.

In the case of your specific accident, it seems that you fell Into the sidewind rather than out of it? In my experience, being blown Out of a sidewind, implies too little tail area. Falling into wind would seem to suggest that the front wheel did not self-steer back into balance as the bike leaned into wind. This might be something as simple as a soft front tyre. It might also be due to excessive trail in the geometry, although the Cmax, with stock Tmax geometry, self-steers fine.

Good lucks getting to the bottom of it!