Slow progress but progress (DIY two seater tadpole trike, 9hp Honda diesel)

[user removed]

As far as weight I just have a rough estimate of around 1200 pounds. I am hoping the CD is low enough to see it hit 60 MPH. It won't be much on hills, but around here they are not that bad. If the lower aero drag allows it to go faster then that would be fantastic. Overall final drive ratio can be changed by increasing the primary ratio between the engine and transmission.

If I see battery tech get realistic then I might just go with an on-off switched electric driven hydraulic pump to charge the accumulator and my drive in the rear to recpature braking forces hydraulically. No controller would be necessary.

So it could be diesel or battery electric or any other configuration or combination of primary propulsion. For now the diesel was cheap.

I think at WOT (sustained power not short term) the engine burns a half a gallon an hour, so we will see how fast that will take it.

regards
Mech

[kafer65]

That's so cool! Looks like a VW IRS trailing arm for the rear. As light as that's going to end up I don't think discs up front will be much of an improvement. My sand rail would lock the front wheels up regularly with stock VW drums up front. It was 1000 Lbs. soaking wet (most of it over the back wheels). I could pick the front end up enough to scoot it around if I needed to with the stock steel wheels and plywood floor.

[redneck]

Old Mechanic

but the long term objective is to build my patented drive for the single rear drive wheel.

That's what I want to see...

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[Kenny]

Interesting build OM. What is the estimated weight distribution?

[hat_man]

COOL x 100

I can't wait to see the finished project and will be following this closely.

I don't know if it is feasible but there are 6 speed trans kits for Harleys giving you a 6th gear overdrive. .087 or something like that.

S&S Transmissions/Baker Drivetrain/JIMS Machine are three of the manufacturers IIRC.

[user removed]

Originally Posted by Kenny

Interesting build OM. What is the estimated weight distribution?

I have not really tried to calculate the weight distribution, or even the overall weight. I can pick up the engine, frame, and front axle myself (individually), maybe 500 pounds total for all 3 or a little more. I think I might go lightweight on the upper structure other than the roll cage. It will have a roll bar behind the seats and another that will serve as the windshield frame. The parallel frame rails will have sheet metal between them, which will add some weight.
As far as distribution front to rear, it will probably be close to 50-50, of course depending on the number of people on board since the would be about 30% of the total weight, assuming two people at 400 pounds.

As far as overall drive ratio, that can be adjusted with the primary sprockets.
In the next few days I will get the transmission and the rest of the powertrain components, basically everything you would need except the Harley motor. Hopefully in a few weeks it will be a roller, maybe even a driver, but I have found predictions that rely on other peoples work tend to be optimistic.

regards
Mech

[sully06]

Another good engine choice is a diesel motor out of a Themo King refrigeration unit. They are little 4 cyl motors made by Isuzu very economical and reliable. I've seen them put in Bobcats before. I want to say somewhere around 30hp so it wouldn't be very fast.

[Kenny]

Originally Posted by Old Mechanic

As far as distribution front to rear, it will probably be close to 50-50, of course depending on the number of people on board since the would be about 30% of the total weight, assuming two people at 400 pounds.

Given a single rear wheel, there is essentially no roll stability at the rear. Since it isn't a 'tilter', the front axle (w/two wheels) provides the only roll stability for the entire vehicle. Also, the 3-wheeled configuration gets complex when suspension is involved because the suspended front axle will allow a given amount of roll, exacerbating the tendency to lean in corners. Just a suggestion, but I would strongly encourage a minimum weight distribution of 65% front/35% rear, and a stiff anti-sway bar on the front. Yes, agreed, keep the mass as low as possible... especially on the rear half of the chassis.

At 500 lbs total, you can probably get away with using bathroom scales under each wheel. This will easily ballpark your weight distribution (given approx. 33% under each wheel). If only one scale is available, just make sure the vehicle is level by using blocks or spacers under the other two wheels when weighing.

-kenny-

[user removed]

It's a roller.

We think it still is under 1000 pounds. I can lift one side off the ground including one of the front wheels.

Now I need to find a 17 inch narrow passenger car tire for the rear Harley wheel. With 400 pounds of payload the suspension compresses about an inch front and rear.

regards
Mech

[night9]

Very cool project!