lowracer's pusher trailer
Thanks
5-7Heaven You could put a big red taillight on a stalk at the rear of the pusher for staking out your space on the street in town. Or make a styrofoam child to sit astraddle the trailer.
MikeJ: Good luck trying to get the engine behind the axle and still have at least 10% tongue weight. That's what you need to avoid handling problems with a trailer. Google trailer design to verify what I'm saying. I've seen improperly loaded utility trailers go into a feedback situation of wagging increasingly until becoming totally unmanageable. The most recent was within the year when I barely missed getting broadsided by such a trailer that within a few seconds skidded increasingly left and right til it got itself and the pickup sideways on the road, then into a ditch. I stopped to investigate and found the heaviest items had been loaded over and behind the axle.
About 18 mos. ago I was hauling an ultralight airplane in a homemade trailer built to carry it. It is streamlined well, but the axle is too far forward. The plane fits in backwards so the heaviest part (engine) was over the wheels which might have worked, but the tailgate was designed to double as a loading ramp and was very heavy. The trailer was unmanageable til I bought bags of pea gravel to put in the front of the trailer to give it proper tongue weight. I intuitively understand why tail heaviness destroys trailer handling, but I can't figure out why adding the pea gravel up front tamed it down. Anyway, It's a fact of life. Be prepared to reposition your engine if it doesn't work out behind the axle. Let me know if & when you want to sell Riley's plans.
Lowracer: I like your stem/hub u-joint hitch. It's a clever construction. I like that you used aluminum angle. Now I know it's workable unless it contributes to the flexiness that is plaguing you. The small amount of weight far above that line has more deleterious effect than the engine weight slightly below that line can remedy. Remember your whole wheel is above that line as well as that superstructue you have there. The camera angle isn't perfectly level, but when I hold a straightedge on the first full length photo it appears very little of the engine is below the line. It looks a little better in the last photo.
Did you check for torsion like I suggested? What were your impressions?
A topheavy trailer fights leaning correctly around a curve. It always tries to fall to the left or right and is able to do that due to the slightest amount of flex or loose tolerances. The only place where flex is a good thing is vertically in the tongue. What I mean is a little flex that is equivalent to having a bit of suspension. A little bit goes a long way. My trailers get it from the curves in the 3/4" electrical tubing tongue and placement of the engine halfway between hitch and tire. Your design is strongest vertically, precisely where you could benefit from a little flex. If you were going for triangulation strength, it should have been to prevent the possibility of longitudinal twist.
I wish I knew what you meant about feeling like it's a tractor trailer. Mine handles the same as it does without the pusher; I just don't have to pedal.
Here's a 20 yr. old clip:
http://www.youtube.com/watch?v=XjEgsKqfi74&feature=g-upl&context=G2afea5dAUAAAAAAAFAA[/URL]
If I had a lower gear ratio for hard acceleration, I can tell I might feel the trailer pushing the bike toward the outside of a curve, requiring me to lean a little against it, but it's certainly not an issue with 3.5 HP geared for 35 mph. I use one on a trike, but am gambling that I won't roll it by cornering too fast. They flip without much warning. I'm referring to the delta type; two wheels in back & one in front.
Too bad we don't have a video of pushers at an agreed upon speed on the same curvy, hilly, bumpy road to reveal the handling effects of different designs.
It concerns me that potential pusher builders might be deterred by prototypes that were abandoned too soon.
How else can you choose nearly any engine and drive train combination and build it without trying to squeeze it in or add it on to your bike. No welding is required. Use a lightweight, fast bike that you wouldn't or couldn't power otherwise. You're only adding a little bit of tongue weight to it. You don't have to dedicate any particular bike to it. Use it on any bike in your collection. All the noise, heat, gas, oil, exhaust and vibration are behind you at a safe distance.
I think the pusher subforum should be just as active as frame or rack mount. By now we should have custom bike/pusher combos that look good, like they have with motorcycle and hot rod trailer combos. We certainly have the talent here.
How about a pusher/pet carrier combination. I'm considering that for my next build. I've got a 55 lb. pup that freaks out unless I take him everywhere I go. He's fine alone in a car or truck though. He waits very patiently for me. I believe he would do the same while guarding his pusher while I run in the store for milk bones and a frisbee. His passenger module could be replaceable with a cargo bay for camping gear and other long haul accoutrements.
How about using a pusher to make a short range electric bike practical for long commutes? Cover the country miles with a fast pusher and secure it somewhere while you use battery power in town. Ideally you would want an electric bike that can freewheel as well as use regenerative braking. Do they exist?
Let's hear from some imaginative members about other development possibilities.
