What is the best 2:1 gearbox for speed 400? - RC Groups
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Jul 17, 2002, 11:51 PM
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Ryan Nau's Avatar

What is the best 2:1 gearbox for speed 400?

I am looking for a 2:1 gearbox for a speed6v 400. I haven't seen any around. Are there any. I need it for a funfly type plane. What size prop works best on 2:1 on either 8 or 10 cells?
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Jul 18, 2002, 12:03 PM
Registered User

Not 2 to 1 but 1.85 to 1

I have a hobby lobby 1.85 to 1 with a speed 400 6V timed 15 degree advanced with a 8x5 Aeronaut folder on 8 NiCads. Have tried 9 1650 Sanyo NiMhs or 8 1700mA sanyo NiCads (Not CP1700s) works OK.

i see that Tower sells i think a Soarstar 1.85 to 1 for alot cheapier. Probably worth trying.

I think a real nice set up would be the 1.85 to 1 with a 7.2V motor and 9 or 10 new Sanyo 1700mA NiMh high capacity cells if your plane can take the weight. advance bout 5 degrees and water break in and use flux ring. Should get reasonable power and very good duration.

I would resist full power for entire flights. My 6v is over a year old and still is working fine.

You need to get hold of some grease that is OK for plastic and lubricate from time to time. They tend to let you know when that time is by making extra noise from gearbox.

try and get at least a ball bearing in output shaft, best get 2 ball bearings though.

Good luck
ron Parigoris
Jul 18, 2002, 02:33 PM
-plancks only-
Franck's Avatar
Cant you gear a little higher ? Especially the 6V 400 version likes to be geared at 3:1 or even 4:1 (depending of the plane you gonna put it on)

Ive used MPJet gears for a coupla flights now, no BB but they're darn cheap!


Jul 18, 2002, 04:10 PM
Superhero, Third Class
astroboy's Avatar
I've good performance, especially for your application, with a 6V 400, Mini-Olympus gearbox(2.33:1), APC 9x6E, and 8 cells. Some might say that's a bit overpropped, but I'm not too often at full throttle.

Jul 18, 2002, 04:16 PM

Ditto to Ron's info. Also you might want to check out the following:

NC-MA001 Adapts GR2906 and others to Speed 400 motors $15.95
NC-MA002 Adapts AP-29 Motors to most 1/ 8" Gear Boxes $15.95

The above are from Kirk Massey at www.newcreations-rc.com

I believe these are the 2:1 ratio nylon housing gearbox with 1/8th inch (replaceable) output shaft which include the prop adapter. These were designed by Tom Hunt at Modelairtech. I have several of these and have found them to be very good. Incidentally I found that the Rocket 400 motor that Hobby Lobby sells to be very good with this gearbox. It is cheap, reliable and is already wired with all 3 capacitors.

As to prop selection, check out the thin electric types from APC, Hobby Lobby, Graupner and others in 7 to 9 inch diameters and various pitches. You didn't say what plane you will be hauling with this combo, so prop selection will depend on that. A combination which runs good on the ground may have a problem in the air because of weight, mass, wetted area, etc. In general, I have had good luck with an 8/4, 8/5 or 7/5 with a 2:1 box.

If you don't have access to a Whatt meter and rpm gauge, check the sound and the heat buildup on the motor, the speed control and the battery pack frequently during full speed bench testing. If you get no heat, you are probably just fanning the air and need a higher pitch prop. Too much heat and you may abuse the components more than is good and will have short runs.

Of course the best way to handle all this is to find someone who has the combination you want and steal all his ideas and research.

Sorry, I didn't mean to be this wordy, but when I hit "flush" is all came out (well not really, there is a lot more).

Good luck