brain storm for g scale

Discussion in 'FAQs' started by scoobyloven, Aug 19, 2003.

  1. scoobyloven

    scoobyloven Member

    i been looking at g scale locos and was looking at a model plane gas motor i was wonder if any way to put the motor in the loco and make it run
  2. jon-monon

    jon-monon Active Member

    Hi Scooby, the big problem will be the same as with the prototype gas-mechanicals, the torque from a gas engine is very low at low RPMs, and so they even have idle at pretty high RPMs to keep running without load. So, as in a automobile, you would need some type of clutch and gearing, which in order to run at prototypical speeds, you would need a heck of a lot of gear reduction. Now, if you can find a little generator, like a motorclcyle alternator, and go gas electric... :D :D :D
  3. billk

    billk Active Member

    And you'd have to run it outdoors or have one heck of a venting system, and you'd have to get some pretty good ear plugs and probably some more understanding neighbors. :D
  4. Ray Marinaccio

    Ray Marinaccio Active Member

    I rode a 7 1/2" gauge F7 and cars that used that idea . He gave us quite a ride. The speedometer in the car I was riding was at over 90 scale MPH. This was at a Maricopa live steamer meet in Phoenix. May work in a G scale.
  5. scoobyloven

    scoobyloven Member

    now the gear thing it wont be a problem but the biggest thing is how to work out statring the loco i had a plan that would use a dcc decoder and model plane servo and for the motor it would be from a rc car becouse you can contorl the speed of the motor a little better the plan on starting the motor would use a pc board that would heat the glow plug and the dcc decoder would run the power to the servo and then the lights and pump for the gas tank i am working out the plan on a electronic program i have to build electronics and test the befor you build it
  6. Dan Vincent

    Dan Vincent Member


    If you used race car parts like a clutch and oversized heat sink head it could be done, the question is why?

    The glo plug engines use an alcohol fuel with either synthetic or castor oil. This oil comes out in the exhaust and sooner or later you will find oil on everything, including wheels and tracks.

    They also have diesel engines which run on kerosene, oil and ether but these are even messier than the glo engines.

    Cooling would be a major issue because most train locos are pretty well buttoned-up and you need air flow to keep these high revving engines cool.

    I've been into model airplane engines since 1951 and have around 500 of them but putting one in a train sounds like a lot of trouble.

    Have you tried "Live Steam?" That's the way to go if you don't want electric.
  7. scoobyloven

    scoobyloven Member

    i would try it out and as for cooling the motor that wont be a problem with a fan but if the oil is going to be a problem getting on the track then i might have to work out a self power system and a way to try to keep the over flow from getting everywhere but then it wount be dcc it would have to be rc but in my eyes i think that would be cool to be able to gas up a loco and then pull it out of the yard under real horse powerand don't have to worrie about a power outage and you are sitting their looking at a train doing nothing the big thing is cutting that life line in the hobby of useing elec for the whole layout
  8. Dan Vincent

    Dan Vincent Member

    OK, assuming you will go ahead with your project, be sure to allow for a fool-proof method of starting the engine.

    Since weight is actually a plus you could add an on-board electric starter powered by an external small tractor or motorcycle battery.

    The trick will be in designing a Bendix type gear release once the engine has fired.

    Some of the smaller race car engines have pull starters.

    Have fun...that's the main thing.
  9. Ray Marinaccio

    Ray Marinaccio Active Member

    I used to service a 4 cylinder backup generator that used the generator as the starter. Just a thought.
  10. cidchase

    cidchase Active Member

    Hi scooby,
    You could use a pull cord starter OK, or use an electric drill with
    some kind of key to mate to the crankshaft. I like the gas-electric idea!! You could use any DC permanent magnet motor (train motor) coupled to the crankshaft for a generator. You can use an R/C throttle on the gas engine; or the gas engine can run at a set speed, and you could use a potentiometer on a servo for an R/C throttle. No clutch, and better speed control! I think there are some pretty effective mufflers for those R/C engines, too. Neat project!!
  11. If you use gas

    first: the 'Nitro' (alcohol + oil) engines come in 2 types: 2 stroke and 4 stroke. 4 stroke is what you'll want, as it burns cleaner nd has better torque at lower RPMs. 2 Strokes waste some fuel on every cycle, but have better horsepower at the same RPM.

    And with a 4-stroke, there won't be unused fuel vapor in the exaust, which happens in a 2-stroke.

    I would redirect your exaust upward to have better dispersion of your exaust (put more in the air, less on the track).

    Obviously, ANY fuel-powered setup MUST be an outdoor setup. The fumes will cause trouble indoors.
  12. Wat Rauscher

    Wat Rauscher New Member

    Sounds like a great idea if you can work out the mechanicals. I feel that the 4-stroke engine would be better, more torque and quieter. There are electric starters for model airplane engines available. Also, look onto the drive trains for model helicopters. They have gear reduction and a clutch. Radio control would be a natural, just make sure you use the 75MHz systems (not the 72MHz aircraft only systems).
  13. Dan Vincent

    Dan Vincent Member


    In what loco are you planning to shoehorn this airplane engine?

    "G" scale is big but space gets used up quickly. If you want to use a 4/stroke, the smallest available are the OS .20 and .26, the HP .21 and .25 and the Magnum .30.

    With all the gearing you will have to use, the OS .26 would probably be the best choice. Measuring my OS .20 it is about 1.75" across the beam mounts, 3.25" high and 4.0" in length. The same meaurements can be used for the OS .26 and Magnum .30.

    The HP .21 is about 2.0" wide at the beam mounts, 3.25" high and 4.25" long. A muffler extends another 1.25" off the right side of the engine. The HP .25 is about the same measurements but I can't check because the one I had is now in Sweden.

    Another .30 fourstroke is made by Saito(Excellent engine) but I have no measurements.
  14. cidchase

    cidchase Active Member

    If the gas electric pans out, it requires no gear reduction or
    clutch, the generator should be able to drive directly from the
    (I believe the generator rpm would be in the power range of the 4-stroke engine):)
  15. Dan Vincent

    Dan Vincent Member

    Most of these small 4-stroke engines put out power in the 9,500 to 12,000 range on a propeller.

    I would still recommend a centrifigul clutch because you sure don't want any load on the engine when trying to start it.

    When they first start up they can be a little balky 'til they reach operating temperature.
  16. scoobyloven

    scoobyloven Member

    well as for the loco it want to try to do it to a gp38 or a gp60 but if i can get my hands on a sd 80 mac i would do that i would only need the shell,trucks and chasey nothing else i have 4 magnum .30 motors from my brother and we been working on a gear box we almost have it down it would have a total of 2 gears and a twin shaft we got the gear box to turn at 2,500 rpm at a 9,500rmp off the motor and up to 9,800 rpm at a 12,000 rpm off the motor with this put on a rc car for testing and at the low gear it moved very slow but when we added stuff to bring it to about what the loco would be it just sat their and as we moved it to the big gear and added to the speed of the motor we got movement we got to about 80 scale miles an hour now on to the fan unit and how to start this with out tuching it
  17. Greg Elems

    Greg Elems Member

    Scooby, sounds like you are on your way. There are G scale SD40-2's and SD45's out there. I haven't seen any SD80MAC's advertised but that doesn't mean one isn't on the drawing board somewhere. Good luck and keep us informed of your progress. :D

    Greg Elems
  18. Dan Vincent

    Dan Vincent Member


    Sounds like you're making progress...

    Do you plan to have a reverse gear?
  19. scoobyloven

    scoobyloven Member

    we are working that out in the gear box i want to keep things as small as i can becouse space is limted and i am working on electronics to run light and the fan and starter but if i don't work it in this loco it would be in the next one been thinking on getting my hands on a dummy and put the electronics and gas tank in their but we will see
  20. Tomsz

    Tomsz Member

    Hi, I made a GP30 in to a live-diesel.I work in a hobby shop, so I used one of our 2-stroke car eng. with a pull start. I also used a radio control airplane starter for the generator. I just put a spur gear on (32 pitch from "HPI"); and ran the generator in the oppisite direction to get power to the motors that came with the eng. already. I ran 20% car fuel, but "Dave's Diesel" makes conversions for the 2-stroke eng. to make them run off Real Diesel fuel. I also put 3 small fans on top where the real eng. would have them to help keep the eng. cool. It runs about 20 min. on one tank of gas, but I can refill it and keep on going. I also have a battery system to back up the generator for when the eng. is off, but when I still want the lights on. If I can help, let me know.

    Have a great time,


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