RC Nitro Two Stroke

[Leadfoot]

I am looking into designing a small less obvious, semi universal motor kit. Most likely friction drive. To keep the size small I am considering to use a nitro two stroke engine from a RC airplane. They produce between 2 and 3 HP but at around 10,000 rpm. My idea is to use a lot of gear reduction to acheive a top speed of around 25-30mph. These motors make no power below 2000 rpm so I would imagine you would have to peddle up to 15mph to get started.

Has anyone experimented with these motors or have suggestions? My main concern is not having enoough power to get to 25mph.

 

[HeadSmess]

fuel.

at around 40 dollars for 4 litres.... and using it at 4 times the rate of petrol in a similar size engine...

and.

hi oil content of 16% makes for problems.


yes, there are spark ignition kits available, with a neat little 1/4 inch by 32tpi plugs(same thread as the standard glo plug)

i have never found any reliable info concerning reliability when converted to petrol.... may depend on manufacturer/model... i know "saito" is now producing a petrol 20cc... apparently has issues though.

i also recomend using a four stroke. less reduction train needed, quieter, less fuel....cost more.

i have my own ideas...in development

 

[Skyliner70cc]

A second that its not a good idea. Fuel would kill you, they spit out tons of oil, and they are loud. They also don't come with a stock airfiltration system so that will need to be devised.

 

[Leadfoot]

Fuel cost is not a concern. I am looking for the most power dense motor I can find. I want to keep the whole unit as small and tight as possible.

 

[motorpsycho]

then you need to think about going electric. check this out.
this was built by a friend of a friend.
http://www.youtube.com/watch?v=WKAMus3oSdw

 

[HeadSmess]

second that. electric.

no noise...what could be more discrete than that? now start thinkin of the power available in a good li-po battery pack... like my 1.2kg model helicopter has approx 1.5Kw surge rating...(14.8 voltsX110A)
on full throttle and max collective, 5 mins. cruising/hovering....it could do for over an hour if i had that much patience... i dont.

or, if you have the machinery...steam, stirling, or compressed air engines... steam being my personal fave.

youll be needing the machinery anyway unless you go electric.

 

[adb140275]

couple of things... you need a clutch that stalls at about 10,000 rpm. the engine will get extremely hot. they turn 30,000 rpm... fuel is expensive. not to be a pessimist, but it just doesnt seem conceivable

 

[motorpsycho]

true, little nitro r/c engines turn a lot of rpms, and supossibly make 2-3 h.p. depending on what size engine you get.
BUT, they do not make the amount of torque that would be needed.
you would have to figure out a gear ratio that would work, some kind of throttle linkage, a clutch, some kind of pulley to replace the spur gear, and you would always have to carry a glow plug ignitor around in your pocket.
besides, the fuel (20% nitro) is $12.00 - $15.00 per quart
I have a nitro r/c dragster, and a quart does not last very long.
These motors were not meant to run for long periods of time and they won't last if you keep them at wide open throttle for a long time, they are designed to run on and off the throttle (unless you spend big $$ and get a nitro airplane or helicopter engine. those engines are designed to run for longer periods of time at w.o.t.
but with an airplane / helicopter nitro engine, you would have to jump up the fuel to 40% nitro which is MORE $$.
I'm not saying that this idea can't or won't work, it just seems like an aweful lot of stuff to go through (and expense) when you can have a quiet, smooth, no hassle electric motor set up that won't be nearly as expensive, or as much of a hassle to get working that will give you better performance, and probably more speed.

 

[adb140275]

rc engines are pretty loud and obnoxious if you go with a good pipe that will let you make 2-3 hp. (i have many nitro powered rc cars myself, its an addiction)

 

[motorpsycho]

rc engines are pretty loud and obnoxious if you go with a good pipe that will let you make 2-3 hp. (i have many nitro powered rc cars myself, its an addiction)

yeah my 1:10 scale r/c nitro dragster has a .18 in it with a hemi head, tuned pipe, slide carb., a high flow air filter and a 2 speed transmission. it will hit 68 mph in a scale 1/4 mile, but it's very hard to control.
I raced it at an r/c dragstip once and i made about 6 runs with it.
it was a blast, but hard to keep it straight.
it is loud, obnoxious, and the engine revs to the moon!
i love the sound of an r/c nitro motor at 40,000 rpms....lol