Building tadpole trike for street use - Fuel Economy, Hypermiling, EcoModding News and Forum

tinkerbill · 09-04-2010, 06:15 AM

Hello fellow modders! Thought I would apprise those who are interested of my current motorcycle project plans. For some time now I have been gathering parts and pieces to build a tadpole (2 front, 1 back tire) trike with covered body. The usual route in this configuration is to put power to the single back wheel however I want this thing to be FWD. Towards that goal I recently scored big-time in the purchase of a rolling Polaris Scrambler 4x4 frame. This model (and others) utilizes a McPearson arrangement for the front suspension with CV axles and small 3rd member up front. I plan on replacing the 3rd member with my own modified differential sourced from an older John Deere riding mower. It already has a 45 tooth sprocket for chain drive. I will be installing a Honda 350 twin out front in the open, kind of like the Morgan 3-wheelers and doing a short chain run back to my modified differential. It will not have reverse but at a planned weight of <500lbs I should have no trouble rolling it back if need be. I'd love to install a diesel engine in this thing but that is not in budget

After this rig is running OK I will start work on a body for it. I'm thinking about 3ft wide in front tapering to about 24/22 inches at the tail end. Suspension and front tires will extend further out of body for an estimated width of about 5ft. Hopefully the frame mods will allow placement of two seats in tandem. I have no idea as to mpg but I'm hoping for at least 60 or more. I plan to run DOT-approved 4-ply street tires on the original 10" rims (22x10x10). That's a little wider than needed but it will look good. It has taken me a fair amount of time just to source the components I now have as I am building this on a pretty strict retirement budget. As time allows, I will be posting a link to pictures of actual rig but for now I am attaching a pic of a trike design that comes the closest to what I have planned. Mine will be a little narrower/taller and of course the engine will be up front instead of out back. I welcome questions and/or suggestions.
Have a good labor day weekend everyone!
tinkerbill

skyl4rk · 09-04-2010, 08:05 AM

Sounds good, I will be watching!

redyaris · 09-04-2010, 11:17 AM

I to have thought about a tadpole trike, but I start with a terratrike bicycle and add a 50cc honda GC50 and solar power... With full solar cell covered body work a la solar challange racers. Such a vehicle with a solar charging system at home would make me carbon zero and energy independent; almost... I dream that such a setup would get around 200mpg driving at night and better than 300mpg in the day for short trips, at about 50mph. The ultimat hybrid

. Your progress will be well wearth watching. Do you have plans for some solar on your project? What I have thought of is some way of useing a 120 watt, or so, solar panel as a body cover part, double duty as it were. This would also reduce the need for a large alternator system. When working on this type of project I always keep in mind a comment made by an engineer friend of mine who said that not being burdened by the facts can allow one to come up with something otherwise unemaginable!

and after you have demonstated that it works everybody then says it was obvious

...Keep on keeping on.

puddleglum · 09-07-2010, 01:50 AM

It sounds like an interesting project and I look forward to hearing/seeing how it turns out. I do have one concern about your purposed dimensions. Raising your seating will raise your center of gravity and the rear seat will move the CG back toward the single wheel, although the front mounted engine should help. A narrow trike with a high center of gravity is a recipe for disaster. Thats why most trikes are wide and low. Just make sure you get the design right before you build it. There is some good info out there to guide you if you do some searching. Robert Q. Riley has some good info on this as do some others. Good luck and have fun.

kawboyCAFE · 09-10-2010, 06:06 PM

interesting thread. i will be watching for the updates. good luck.

redyaris · 09-24-2010, 10:00 AM

tinkerbil Do you have some pic's of the Polaris frontend/frame that you have for the tadpole project? I have a Honda 350 Quad in the yard that I never use that could be turned into something interestina and fuel efficiant. Do you have info on alternat tires and rims for the street?

jmygann · 09-25-2010, 12:20 AM

Phil Chipman's WIND

hmiwb · 02-09-2011, 06:40 PM

I'll be following your project as it progresses. Good luck with it. I'm currently looking into mounting a small 49cc engine on a bicycle to see how that works out. Could be interesting. If that Honda 350 you are going to use is from the '70s you might want to gear it tall and keep the rpms fairly low. I owned a couple of those and they are severe vibrators when you get the revs up to highway speeds. I could never take a long trip on either of mine as my hands and feet quickly went numb. Just something to be aware of.

tinkerbill · 02-11-2011, 05:13 AM

RedYaris,
Terratrike huh? Even their least expensive recumbent is too expensive for me! Unless you already own one, you are going to have way over $1000 with the cost of a trike, Honda motor and fittings, plus solar cell, bats, controller, wheel motor, etc. Now that I list it all out, I'm thinking WAY more that $1000! Do I have plans for solar? No, I will be doing good to get the thing built and running with a ICE. Maybe many moons down the road. Good luck!

Quote:

Originally Posted by redyaris

I to have thought about a tadpole trike, but I start with a terratrike bicycle and add a 50cc honda GC50 and solar power... With full solar cell covered body work a la solar challange racers. Such a vehicle with a solar charging system at home would make me carbon zero and energy independent; almost... I dream that such a setup would get around 200mpg driving at night and better than 300mpg in the day for short trips, at about 50mph. The ultimat hybrid

. Your progress will be well wearth watching. Do you have plans for some solar on your project? What I have thought of is some way of useing a 120 watt, or so, solar panel as a body cover part, double duty as it were. This would also reduce the need for a large alternator system. When working on this type of project I always keep in mind a comment made by an engineer friend of mine who said that not being burdened by the facts can allow one to come up with something otherwise unemaginable!

and after you have demonstated that it works everybody then says it was obvious

...Keep on keeping on.

tinkerbill · 02-11-2011, 05:20 AM

Puddleglum,
I will only be using the front end assembly of the Polaris quad, not the frame. I have already given the CG thing plenty of thought and will be sitting just aft of the front end, down low, not up high like the donor quad. With 3ft of body width in front and A-arm assemblies sticking out from there I will probably end up with a tire-to-tire outside width of at least 60". Thanks for the concern though.

Quote:

Originally Posted by puddleglum

It sounds like an interesting project and I look forward to hearing/seeing how it turns out. I do have one concern about your purposed dimensions. Raising your seating will raise your center of gravity and the rear seat will move the CG back toward the single wheel, although the front mounted engine should help. A narrow trike with a high center of gravity is a recipe for disaster. Thats why most trikes are wide and low. Just make sure you get the design right before you build it. There is some good info out there to guide you if you do some searching. Robert Q. Riley has some good info on this as do some others. Good luck and have fun.