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NORTHWESTERN UNIVERSITY: Solar Car Project

 
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elden simons



Joined: 11 Sep 2003
Posts: 369
Location: Brampton, Michigan

PostPosted: Sun Mar 14, 2010 8:21 am    Post subject: NORTHWESTERN UNIVERSITY: Solar Car Project Reply with quote

Well, lets have this Solar Car Project topic down here with the rest of the postings, insted of the Header area....or does it not really matter?
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Tammy and Elden have Pulse #308 from 1988.Built in Butcher's Barn and presently sets inoperative in their garage. We are still keeping it!
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elden simons



Joined: 11 Sep 2003
Posts: 369
Location: Brampton, Michigan

PostPosted: Sun Mar 14, 2010 8:51 am    Post subject: The Pulse Design Reply with quote

So, what has been the problems of the Pulse design?
It has been said that the placement of the outriggers are not ideally located to work in favor of proper turning arcs made during steering.
I once contemplated the use of outrigger wheels designed like those used for the front of shopping carts. Multi directional. There are such tires on zero-steer lawn mowers. I really wonder as to how such a set up reacts to Pot Holes?

Then, there are the problems of side winds hitting the side of the Pulse. I mean, such side winds are bad enough for traditional motorcyclists and worse for Freight haulers (18 wheelers).
Such sidewinds have caused sudden concern due to not only to handling, but also the disconcerting surprise of finding oneself in an entirely differantly lane. Added to that, such a 'shove' may cause the air shocks (for such models with such installed) to 'unload' as well and really ruin handling.

The Pulse really doesn't achieve balance where the stabilizers rarely contact the roadway. There will always be that friction of a non contributing wheel. A Gyroscope would be nice, dispite its own reluctance to allow leans for better turns. The Gyroscope would have to be on its own controlable gimbal that works in conjunction with the steering.

A Pulse should not become a one-seater if you really dig giving rides to potential dates.

If you are going to have a windsheild like the Pulse, try to afford glass. Unless there is some sort of plexi that accepts Rain-X. Rain-X is the best for vehicles that have such an odd curved windsheild. Don't know much about any other formula that can be used for plexi like windsheilds.

Oh, and don't forget seat comfort. Unless the students of the University are used to sitting on hard student chairs, even the seats in our original Pulses can get uncomfortable.

A 'Heads-Up' display of necessary info. or better mounted indicators.
Better access to the engine and engine removal from the frame.

As for the requested details of wheelbase and such, The main Autocycle archive home page should have something. I don't remember.
Elden
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cook



Joined: 14 Mar 2010
Posts: 3

PostPosted: Tue Mar 16, 2010 5:33 am    Post subject: Reply with quote

Mr. Simons,

Thanks for your feedback! Do you know where you heard that the outrigger placement was not ideal? This is definitely the biggest question we're facing as we try to design the car because we have literally infinite possibilities for where to mount them, how wide to make the outriggers, how high on the body to mount them, and how stiff/soft the suspension on them should be, and whether we want a full coilover shock, airbag shocks, or just rubber bushings and a supporting arm that's designed to flex. Lots of questions, very few answers.

Regarding using shopping cart wheels for the outriggers, it's not a bad idea because that would ensure that there's no scrub on that wheel because it will automatically follow whichever arc is most efficient. I don't think that the bearings are very efficient in those though, and it's unlikely they'll be able to support a few hundred pounds on 1 wheel, and you bring up a great question about potholes, especially with such small wheels, though the idea is definitely on our radar. Add that to the questions I listed above!

I am quite concerned about side gusts. Our car's bodywork will not look like a pulse, but instead will be like a T-shape from the front. The top of the T will be covered in solar cells, the vertical part of the T will be simply to enclose the driver and all the internal bits of the mechanical and electrical systems. The driver's head will stick out above the "T" in an aerodynamic bubble.

You say that the pulse doesn't really balance itself on the road, which I assume means you spend most of your time driving on 3 wheels (2 main and 1 outrigger)? Does anybody have experience messing with the outrigger wheel height in attempt to lift them high enough so they don't interfere and the bike actually does achieve balance relatively easily? Or is it more likely that we'll end up with that 3rd wheel on the ground with nothing we can do about it? It does give the advantage, however, that we can decide which side to lean towards based on where the sun is in the sky Smile

Unfortunately, this will have to be a 1-seater. We're engineers, we don't go on dates! Razz (just kidding)

A HUD would be awesome, I completely agree. I keep pestering our electrical engineers to design one, but it would take too much time and would also need electricity to power it...something we try to avoid wasting.

I hope that clears up some thoughts and questions you were having.

I have another question for the forum:
IF YOU DRIVE YOUR PULSE TOO FAST IN A TURN, HOW DOES IT LOSE TRACTION? UNDERSTEER? OVERSTEER? HOW DO THE OUTRIGGERS INTERFERE WITH THIS BEHAVIOR WHEN SLIDING AND/OR AT THE TIRES' TRACTION LIMIT?

Thanks!
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Bob Cervero



Joined: 26 Aug 2003
Posts: 63

PostPosted: Tue Mar 16, 2010 11:24 pm    Post subject: Reply with quote

From what I read you are trying to design an ultra light, efficient vehicle with a lay out similar to the Pulse. The only idea you hope to use from the Pulse is the 2 wheels inline to minimize friction and drag. The outriggers are simply to keep your vehicle from falling over.

Nothing would actually be used from the Pulse. The 2 inline wheels are a good idea. I would forgo any complicated suspension in favor of simple rubber bushings to keep weight down. The reason a Pulse cannot ride on only 2 wheels is the fact that it has a steering box instead of a handle bar arrangement like a true motorcycle. The steering box isolates the feedback of the rake/trail stability of the front forks from the rider.

The problem a Pulse encounters is a continuous tight circle is flex in the swing arm. The swing arm flexes until the outrigger takes up enough of the load to allow the tire to slide sideways. then the swing arm flexes again and the cycle repeats. A more rigid swing arm would solve this problem. An outrigger that castered somewhat freely would help also.
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