A Fantastic Twin-Engined Idea For Cheap!

[5-7HEAVEN]

PC got me thinking after I posted about my BMP modification!!

There are very few potential MB fan members who might be interested in front drive. Nevertheless some guys, myself included, would mount their engine up front.

In my BMP thread I mentioned how you could modify a rear friction drive assembly to become a FRONT friction drive. Basically you just need to drill engine mounting holes directly on the other side of the engine. After drilling for U-bracket and rear support strut holes, your modified friction drive kit will fit either front or rear tire. Then everything bolts in place and a shorter throttle cable completes the install.

HOWEVER, I just had an epiphany!!!

Since there are now engine mounting holes on BOTH SIDES of the engine housing..

THEN YOU CAN MOUNT TWO ENGINES ON THE SAME REAR FRICTION DRIVE ASSEMBLY!!!

However, the right-side engine needs reversed-rotation. This can be accomplished in at least two ways:

A reverse-rotation clutch could be mounted and somehow adapted to the lengthened driveshaft on the right side.

Some CCW engines such as the GP460 engine can be modified to run clockwise. Then the motor would bolt on and mate directly to the lengthened driveshaft. The clutch drum and shaft on the right side could be welded together to prevent loosening. ORRR, the drum could be welded shut; then IT and the modified shaft could be machined for left-hand threads to prevent loosening.

The "ace-in-the-hole" is Staton's adaptor that they use for his expensive dual-engine rear gearbox. If this vendor sells this adaptor separately and reasonably, this would also be an option.

This is Staton's dual-engine option:http://cgi.ebay.com/TWIN-Subaru-Rob...5|66:2|65:12|39:1|240:1318|301:1|293:1|294:50

My idea would cost MUCH MUCH less and installs on YOUR bicycle.

To have TWO ENGINES driving ONE friction roller would be AWESOME!!

Does anyone else have any ideas to mate that right-side second engine? Unsure if throttles have to be synchronized, maybe not precisely.

 

[Rich 240]

The only concern I would have would be regarding the ability of the tire to stand up to a roller being powered by the two engines.

I could foresee a knurled metal roller overcoming the "friction" between itself and the tire and sawing the tire much like a rasp or file especially on a steep hill.

Maybe so, maybe not. It's an intriguing concept and certainly worth experimenting with.

The extra power of another engine may be just right for the simple friction drive to hoist bike and rider up over steeper terrain that the single engine friction drives struggle with.

A larger diameter roller could perhaps help the tire in handling the extra power of two engines and would also increase the top end speed, too.

Good luck with the project...keep us posted!

 

[5-7HEAVEN]

Hey Rich,

Installing dual engines on rear drive is not one of my projects at this time.

Right now I'm simply interested in modifying rear friction drive to front drive. The twin-engine idea was a second thought.

 

[s_beaudry]

Nice Ebay auction they have, but seems kind of like overkill to me.

Redundancy is a good thing a lot of times, but on a bicycle???

 

[5-7HEAVEN]

Redundancy is a good thing a lot of times, but on a bicycle???

JMO, redundancy is GREAT on a bicycle. When (not if) the engine drive falters, the other engine gets you home.

There have been MANY times that one engine or drive assembly has failed on "The Dragon Lady", my twin-engined monster. The other motor keeps on plugging away. When I'm in traffic, I don't even stop to raise the dead engine off its tire.

I just keep on trucking, especially if I'm almost to my jobsite.

 

[5-7HEAVEN]

http://www.staton-inc.com/Details.asp?ProductID=2661[/url]

http://www.staton-inc.com/Details.asp?ProductID=2661

http://www.staton-inc.com/Details.asp?ProductID=3276

It seems that the Staton gearbox is drilled through on the left side. The clutch shaft connects internally to an existing intermediate gear, allowing the left-side engine to turn counterclockwise and help drive the gearbox.

Sorry, no reverse-rotation device found...yet.

 

[Happy Valley]

If an engine quits, that's why you have pedals, LOL.
Just kidding.....someone had to say it.

 

[Porkchop]

Why would 2 engines on a friction drive, same tire, be any worse than one engine as far as tires stress/wear out ? I talked to BMP about using the GP460. James said it would probably be way to much power. My reply was, have enough sense not to gun it every time you take off and make the roller slip on the tire. If the roller slips on the tire, sure it's going to wear out quickly.
One GP460 has more power than 2 of the engines that I have on my BMP friction kit. I'm sure there's a litmit with all this stuff somewhere, but I think the big thing is just use some good 'ole common sense and treat these things with a little respect and keep 'em safe !

..... PC .....

 

[duivendyk]

People tend to confuse 'power' with torque,the GP 460 for instance has roughly the same torque as a Mitsu engine with a similar displacement (engine size and torque closely correllate),but it has much better rev. capability,while maintaining torque.For this reason it is capable of much higher output power.But to use this effectively requires lower gearing.I don't think having twin engines on one roller makes much sense,the combined torque will be excessive for a single roller to handle,esp in inclement weather.

 

[Mountainman]

well I don't know
but -- that set up looks pretty nice to me
as always looking at that THING makes me wish to have one
but -- is that truly the #2 motor bike Iam wanting ??

does look kind of BIG with two of those THINGS !!!

ride that THING