Another jet kart

steve · Post by **steve** » Mon Jun 28, 2004 2:11 am

I have just finished work on a go-kart powered by two lockwoods producing about 20 lbs thrust each. This vehicle is somewhat unique in that I can convert it to a land sailer by removing the engines and putting the mast from a sunfish sailboat in the bracket in the front. My friend and I will be testing it sometime in the next few days providing that we can fix the ignition circut (it is the one from bruce's website- something burned out but we don't know what. any help would be appreciated!).

and now, the pictures:

Anthony · Post by **Anthony** » Mon Jun 28, 2004 2:44 am

How fast do you plan to go?

I have some concerns over the 3-wheel concept. It may be hard for you to turn, as usually such a concept requires the ability to lean on a side or having a large wheel. However, I must say it makes things easier, yes. Awesome work, overall!

For an original 3-wheeler concept, take a look at this :

http://www.go-t-rex.com/

Bruno Ogorelec · Post by **Bruno Ogorelec** » Mon Jun 28, 2004 10:15 am

Steve, a wonderful machine! Good luck and good fun! Post some photos of the engines blazing and the kart running madly!

Why do people insist on having electrical ignition circuits for pulsejets? They are completely unnecessary. You can fire a pulsejet with a kitchen sparker, or with a flaming bit of newspaper or anything else you can think of.

Bruno Ogorelec · Post by **Bruno Ogorelec** » Mon Jun 28, 2004 10:25 am

Avenger wrote:For an original 3-wheeler concept, take a look at this :

http://www.go-t-rex.com/

A lovely thing. I'd have based it on a BMW 1200 twin engine and transmission package, though. It has a nifty shaft drive and swing angle compensation linkage, which chain drives never have. Also, the BMW twin doesn't vibrate. harley mills not only do, they define vibration. You have to be a girl, really, to appreciate that particular aspect of a Harley engine.

Anthony · Post by **Anthony** » Mon Jun 28, 2004 3:01 pm

brunoogorelec wrote:
Avenger wrote:For an original 3-wheeler concept, take a look at this :

http://www.go-t-rex.com/
A lovely thing. I'd have based it on a BMW 1200 twin engine and transmission package, though. It has a nifty shaft drive and swing angle compensation linkage, which chain drives never have. Also, the BMW twin doesn't vibrate. harley mills not only do, they define vibration. You have to be a girl, really, to appreciate that particular aspect of a Harley engine.

Well, let's see it from a point of view : Harleys can attract girls because of this aspect, so a guy owning an Harley is more attractive... I must get one!

steve · Post by **steve** » Mon Jun 28, 2004 3:03 pm

I have some concerns over the 3-wheel concept. It may be hard for you to turn, as usually such a concept requires the ability to lean on a side or having a large wheel.

If you look closely you can see that it has a very low center of gravity and concequently very stable. I designed it this way primarily for it's land yacht role. stability is especially important when sailing because the frame needs to be able to counteract the force of mast and sail trying to roll it over. as a result, under pulsejet power I could probably make sharp turns at 50 mph without fear of tipping over.

How fast do you plan to go?

I just want to be moved by the engines and have no particular cares about speed. because of this I will probably only let it get up to 30 mph. My friend however is somewhat psychotic and wants to get it up to at least 50. hopefully I can talk him out of it before we make our test runs.

Anthony · Post by **Anthony** » Mon Jun 28, 2004 3:10 pm

In a straight line, 50MPH shouldn't be a problem, but the turns scare me.

When I was talking about the turns, I was thinking about the fact a small single wheel might not provide enough contact surface and adherence to turn hard at higher speeds.

steve · Post by **steve** » Mon Jun 28, 2004 3:21 pm

I agree, In a straight line 50 won't be a problem. The problem is that I dont have any straight areas that I can easily test in. The plan is to use the dual redundant brakes to slow down for the turns so that skidding shouldn't be an issue (except when my friend is driving)

Anthony · Post by **Anthony** » Mon Jun 28, 2004 3:33 pm

A parking late at night might be a nice place where to put up a show, if you find a big enough one.

Anyway, maybe on a next kart you could try some kind of thrust vectoring? Putting the engine stands on a plate controlled by the steering wheel, wich still controls the front wheel.

steve · Post by **steve** » Mon Jun 28, 2004 3:38 pm

thrust vectoring is an interesting concept but I don't think it would be very practical for a land vehicle. If you think about it, asymetrical thrust would only increase the likelyhood of a skid or spin while having little or no effect on steering effectiveness.

Anthony · Post by **Anthony** » Mon Jun 28, 2004 3:43 pm

You're right.

Why I am not really confident in the single front wheel concept is that I get to speeds up to 65kp/h (~35MPH) in bicycle and it's really hard to turn.

Could you get the wheel to lean on its side for more grip while turning?

steve · Post by **steve** » Mon Jun 28, 2004 4:15 pm

I know what you are talking about. once or twice when I was on my bike going at high speeds I was unable to turn fast enough and came very close to crashing. I think this is due to the gyroscopic effect of the large and somewhat heavy wheel spinning at high speeds. I had not considdered what effect this might have when applied to the go-kart. The only solution I can think of is simply to slow down to less the 30 mph before attempting anything more then a gradual turn.

Bruno Ogorelec · Post by **Bruno Ogorelec** » Mon Jun 28, 2004 4:22 pm

steve wrote:I know what you are talking about. once or twice when I was on my bike going at high speeds I was unable to turn fast enough and came very close to crashing. I think this is due to the gyroscopic effect of the large and somewhat heavy wheel spinning at high speeds. I had not considdered what effect this might have when applied to the go-kart. The only solution I can think of is simply to slow down to less the 30 mph before attempting anything more then a gradual turn.

Well, turn the thing around and have two front wheels (better grip in corners; better stability) and have the rear wheel steer. Believe me, there's no corner steep enough for you not to turn into it. Your only limiting factor will be the tire grip. When you have inertia overcome the tire adhesion, no steering system in the Universe can help you.

steve · Post by **steve** » Mon Jun 28, 2004 4:49 pm

I think we will be OK with the current set-up as long as we don't do anything stupid. We have done some stering tests by pushing it down steep hills near my house and making violent turns back and forth and it seems to respond well. Perhaps the fact that there is a lot of weight on the front wheel (at least when compared to the bike it came off of) is giving it a better grip on the road.

steve · Post by **steve** » Mon Jun 28, 2004 5:40 pm

This is a neat shot of the kart with the protective tarp over it. It looks much more substantial and imposing like this. I think the bird on the front is a nice touch too!

(You can tell that I'm bored because Ive made about ten posts in the last hour. It's about time to find a job)