output torque

[fleebell]

Does anyone know about how much torque in in-lbs or ft lbs the 49cc engines average at about 3600 rpm or anywhere else in the rpm ranges?

I've tried a number of different searched but can't find anything here on it.
Lee

 

[Tad Bit Tipsy]

Check this out....
Item # LCD8010Y07, LCD8010Y Self Powered Engine Tach/Hour Meter sparks every other engine revolution on ENM Company

Each engine has its own rpm range, mine has gone up in the 6500+ but its an 80cc. Don't know if this happens in a 49cc, but I don't see why not. With a meter you can control you idle speed not only by ear but with the gauge.

 

[fleebell]

Thanks but that's not really what I'm looking for. What I'm doing is building an adapter that uses a one way ball clutch bearing to make a free wheel setup to replace a regular bike free wheel on the jack shaft of my trike. I want to make sure I get a one way bearing that has a big enough torque range.

Lee
packrat workshop index

 

[Norman]

Fleebell I put a link from the high performance posts to here maybe some one will help you out.

 

[Tad Bit Tipsy]

Whoops, sorry totally zipped through your question and saw RPMs. Its a basic rule that 1 HP equals around 3 ft lbs of torque +/-. Of course how that is transfered to the wheel is the deciding factor. You have to factor in length of chain, teeth, wheel base, etc. Wish we could dyno test these things...

 

[fleebell]

Thanks guys,
That was the info I needed. From that info,the ball bearing type freewheel clutch I was looking at for making a adapter plate should work fine.

Lee
packrat workshop index

 

[Creative Engineering]

fleebell,

A sprague rated for 10 Ft./lbs. or more will do it with a good safety margin.

These engines produce somewhere around 2 H.P. out of the box...give or take a few tenths.

The basic formula is Torque = 5252 X H.P. divided by rpm

Torque at the crankshaft is about 1.5 Ft./lbs. @ 6000 rpm

There is a 4.1:1 internal reduction in the engine.

4.1 X 1.5 gives approx. 6 FT./lbs. @ the engine drive sprocket.

If you plan on another reduction prior to the sprague simply multiply 6 X the ratio of the reduction for a final torque value.

This isn't precise, as the actual H.P. and rpm where max torque is produced are unknown. It is close enough to choose the correct sprague, as you will want one that is over-rated anyway.

BTW...A commercial quality sprague, (One-way bearing), will outlast a bicycle freewheel 100:1.

Jim

 

[Cabinfever1977]

Heres what i got off the gasbike site: for a 48cc starfire gt2 grubee engine:

Maximum Output: 1.2kW /6800rpms or 1.6hp/6800rpms
Maximum Rotation With No Load: 8500rpm
Maximum Speed: 40km/h or 24.8mph
Maximum Torque: 2.4Nm / 4500rpms or 1.77ft-lbs / 4500rpms
Power: 1.2 kW or 1.6hp
Fuel Consumption: 480g / kWh

My 48cc starfire gt2 grubee engine plate says 1.95hp and does 30.6mph

 

[stv1jzgte]

This graph is of a 48cc slanthead i got from zbox that i use to have on my bike. Unfortunatly no rpm was logged.

 

[fleebell]

fleebell,

A sprague rated for 10 Ft./lbs. or more will do it with a good safety margin.

These engines produce somewhere around 2 H.P. out of the box...give or take a few tenths.

The basic formula is Torque = 5252 X H.P. divided by rpm

Torque at the crankshaft is about 1.5 Ft./lbs. @ 6000 rpm

There is a 4.1:1 internal reduction in the engine.

4.1 X 1.5 gives approx. 6 FT./lbs. @ the engine drive sprocket.

If you plan on another reduction prior to the sprague simply multiply 6 X the ratio of the reduction for a final torque value.

This isn't precise, as the actual H.P. and rpm where max torque is produced are unknown. It is close enough to choose the correct sprague, as you will want one that is over-rated anyway.

BTW...A commercial quality sprague, (One-way bearing), will outlast a bicycle freewheel 100:1.

Jim

The engine I'm using came from an X1 pocketbike. It has one of those belt type transmissions on it that changes outputs. The motor has a 12t and is driving a 44t on that side of the jack shaft. The other side uses 2 28t gears. One is mounted solid to the shaft and drives the rear wheel chain and the other is operated from the pedals. It drive a 20" rear wheel with 7 speed gear cluster than came of a wally world kids mountain bike. I don't know the hp of the 49cc engine but the trike will do 32 mph flat out in high gear on the rear wheel. It pushes about 300lb altogether with me on the trike and when it gets above about 18 mph I don't pedal with it.

Here is a drawing of the jack shaft setup

bigger pic: http://www.packratworkshop.com/pics/jackshaft.jpg

Here are two versions of the adapter I'm thinking of making. It will replace the freewheel the 44t gear is currently mounted on.

bigger pic:
http://www.packratworkshop.com/pics/bclutch2.jpg

bigger pic:
http://www.packratworkshop.com/pics/bclutch3.jpg

Lee
packrat workshop index