VAPER-ACE

HOW FAST WELL A 33cc CHAINSAW ENGINE GO[MPH].
CAN SOMEONE TELL ME.

Mad Wax

From the crankshaft or after gearing? Check engine manu. for engine specs (rpm)

Final car speed will depend on gearing, rpm of engine, useable power band, torque, mass of car, road conditions (off road/on road- smoothness etc) tyres, acceleration etc (taking into account usable space) friction (and location of friction- on higher or lower gearing area?) and I guess aerodynamics also.

Acs_guitars

My Feedback: (3)

As mad wax said, it all depends on the gearing. The typical RPM is around 18000 to 22000 I believe for chainsaws. One request though.... Please don't post in all caps, it is a little on the annoying side when seen in forums.

mightycasey

What have you been smokin??? 18000-22000 for a chainsaw motor??? I think NOT. More like 7000-9000 is the correct RPM range for chainsaws. If you use Zenoah motor then 14000-18000 RPM. Chainsaw motors have mor HP than RPM.

Acs_guitars

My Feedback: (3)

Maybe for 40cc and bigger, but a 29cc-33cc typically (from what I have seen, read, and been told) has no lower than 15000 RPM. If that is wrong, then it is wrong. Chainsaws have more torque than HP actually... HP is nothing without torque.

Canadian_RC

Acs_guitars is correct, HP is nothing without torque. In fact, HP = Torque x RPM/5252.

jimbo1890

This torque formula you are quoting Where does it come from? is it engine specific? or is it a general formula?

Doesn't sound logical to me. I would have thought that different engines produced different torque curves.

Mike@Accurate

That is the formula for HP. You measure torque with a dyno, and then solve for HP. All torque/HP curves WILL cross at 5252 rpm. You can't have more HP than torque below 5252, or more torque than HP over 5252. Different engines do produce different TORQUE curves. The HP curve is just a function of the torque curve. Torque is the amount of work something can do, HP is how fast it can do that much work. MIKE

jimbo1890

Sorry to be such a dill

It still did not make sense to me so I found this:
quote:
Watt’s horsepower formula was based on several calculations. The pump horse walked in a circular path tethered to a 12-foot lever arm connected to what was, essentially, a crankshaft that turned the pump. Using the value (pi symbol) (=3.14) and the formula

(2 x pi) x radius

to calculate the circumference of a circle, this meant that the horse walked approximately 75.4 feet during each revolution of the crankshaft, i.e. (2xpi) x 12 =75.4.

Watt calculated that the horse traveled with a force of 180 pounds, and that it traveled at a rate of about 144 revolutions per hour, or about 181 feet per minute. By multiplying the two quantities, Watt quantified the horse’s measurable leverage—i.e., its torque—at 32,580 pound-feet per minute. Converted (and rounded off) to 33,000 pound-feet per minute. Watt had his 1-horsepower equivalent.

Engine horsepower is the relationship between known engine torque at specific rpm divided by Watt’s equivalent unit of one horsepower. Simplified, the equation is:

Hp = rpm x torque
5,252

Conversely, to calculate torque the equation is:

Torque = 5,252 x hp
Rpm
endquote:
http://www.offroaders.com/info/tech-...wer-torque.htm

thanks. I find it hard to understand and therefore believe a formula untill I can see how it was derived.

Mike@Accurate

I work in a shop with an old engine water-dyno. We use it all of the time and I like to spot bogus torque curves in adverts. Many don't understand the 5252rpm point. I knew the whole pony/coal thing. I'm glad you dug it up for a refresher though. Enjoy, MIKE

MrMikeG

Any one here actually run a Tach on their RC cars? I have a sendec for my boats but haven't had a chance to put it in the truck yet.

ammdrew

we see 21500 on fullmod with onroaders on the track, on stock motors we regularly see 19800. this is peak rpm seen on the track, usually the end of the back stretch, not prime power point. If we get some tire spin we will see 22500 in the mods. The best way we have seen to monitor is the oddie box, some tachs work great but the micro tach will not read above 19999, works great for setting the clutch though.

ibstar

ever been to a rolling road ?
its possable to adjust the torque with out changing hp

CRIPTKEEPERBNCER

I have looked at chainsaw motors and can't find any motors with that high of RPM off the shelf. All I find is 9000 Rpm max. What brand and where can I find such a motor. Chainsaw motors are cheaper than those modified goped motors.