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Hi Craig, thanks for your insight!
I follow your contests with great interest and I’ve been a long-time fan of your ethos on “doing more with less”. But what are you now suggesting? “doing more with a bit more than I originally thought”.
I agree with your points about the Ninjas but I draw some different conclusions from your Helix experience. Firstly, you have achieved 100mph (or 70mph into a 30mph headwind as you put it) with your stock 16hp Helix, surely that is proof that the goal is attainable.
Your problem is that you have not been able to it without exacting a penalty on your Helix, which has suffered reliability issues. I’m sure that only you can know the full circumstances surrounding the mechanical failures, but as an observer I would like to make a few points.
The benefit of a low aero drag body, is that it lowers the power requirement to meet the speed target, so your Helix (or my C90) will be under the same stresses at 100mph as they were at their original top speeds (assuming that gearing alteration has kept engine speed in the same envelope).
My C90 would run all day at 50mph, which with current gearing equates to 75-80mph, and is well within the design parameters. Providing there is no failure of cooling and lubrication systems, mechanical wear will be at a reasonable rate (we must accept some). I accept that higher rpm necessary to meet the Vmax target will reduce engine life, but I’m not going to ride “flat-out” all the time.
You have mentioned that your last motor had a head-gasket failure. The normal failure mode is due to either, raised cylinder pressure, cooling system failure, or degradation of structural components (castings) due to metallurgical issues. I believe you ran a “stock” motor so you can exclude the first possibility, but what about the others? Could you have just been unlucky?
Without conceding that the Helix motor was the wrong choice, I do agree that the 250Ninja is a better choice, but maybe not as good as Sendler’s Honda 250. But, my main reason (for feeling so) is in the transmission type and wheel diameter. I always thought you were fighting a loosing battle by starting with a scooter platform.
However, I think we both agree on the “horizontal” engine style being best for a comfortable reclined riding style with aero efficiency – what a shame nobody makes one (yet)!
You may be interested to know that I have already started on a 250cc “horizontal” liquid cooled, single cylinder motor mated to a six-speed manual gearbox that fits within my frame design. It’s not part of this project, but should be ready within a year of meeting my current goals, which I remain confident about reaching.
Regards
Pete
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