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[invader1]

After searching the internet for a belt drive for a Graupner Speed 700 I have about given up unless someone here can send me in the right direction.
Maybe there are hobby shops on the east side of the pond that still carry them ?
If I had the time I would get the gears and the belts and make it. I suppose a smaller motor might do O.K. but I would rather use what I have.
Are there online European hobby shops that still stock or sell these units? Any help greatly appreciated.
                                                                    Invader1

[Martin (Admin)]

Belt drive for a Springer sounds a little over powered, what size propeller are you planning to use?

I used a Robbe gear reduction unit in mine (with a 600 size motor) and changed it to direct drive after the first run.

    http://www.modelboatmayhem.co.uk/My_models/Springer/index.htm

[invader1]

Right now I have a 1.5" three blade prop-not really tuggy looking but it's all I've able to find over here. It's an Octura 2137.

[grasshopper]

Here you go, friend - as they say this side of the 'ditch' "Fill Yer Boots'...

http://www.davall.co.uk/catalogue.php

For a tug you can never have too much power - you just have to use it correctly!

[invader1]

Martin-nice series of build pictures.
I am afraid of overheating the motor, especially where I'll be running on 12 volts with that prop which has some serious pitch.

[invader1]

Grasshopper-Thank you for the information, I will have to do a lot of reading

[chipchase]

Have you thought about the MFA/Como Drills 800 or MFA/Como Drills 850 series

[invader1]

Thanks Chipchase-I'll have to give that some thought. I know those are pretty pricey but beggars can't be choosers. If worse comes to worse I might have to go for that.
                                                                                                       Invader1

[nick_75au]

Would you be better off getting a more appropriate motor? It would probably be cheaper than a belt drive if price is an issue.
Something that does about 6000-7000 RPM at the voltage your using.

For 6 volts a Speed 500 E or Speed 600 14.4v perhaps
or a high turn 540 Crawler motor say 50-70 turn.

Cornwall Model Boats have some belt drives on their gearbox page.

Nick

[Subculture]

Or even look at a brushless motor and controller, no belts or gears needed. The combination linked to below costs $21. You can get higher kv motors depending on the voltage you're running at.

http://www.hobbyking.com/hobbyking/store/__6943__TURNIGY_Bell_TR2410_12_600kv_Outrunner.html

http://www.hobbyking.com/hobbyking/store/__11742__HobbyKing_Brushless_Car_ESC_30A_w_Reverse.html

[nick_75au]

Do those little bell motors have enough grunt for a 40 MM prop? Not at 12 volts going by the Specs.

I know the larger DT700 easily powers a 55-60 mm on 6 volts and I've got a pair driving twin 40mm at 11.1 volts inbn the Axebow

I use a 1000 Kv KA22-20 on 6 volts for one of my springers. Its perfect I would say

Nick

[Subculture]

The wattage looks on the low side, I think that that is an error to be honest; 48 watts for a burshless motor with that can size doesn't compute for me, and if you look up the spec of other similar motors, they're all around the 100 watts rating, which makes more sense. More than a 100 watts in a springer would be overkill, no?

I have two dt700, excellent motors, mine can swing a 50mm x-pitch two blader on 3s lipo no problem, so I guess if you want to play it safe, go for one of those, as it will have a 40mm prop for breakfast.

[nick_75au]

10*4.7 that is what I use on my air boat, on a 750 Kv motor it pulls 9 amps its a Turnigy D2836, when you reed the specs on that one its a higher wattage but they suggest a 9X6 ??

I think I will stick to boats or take the HK specs with a grain of salt

Nick

[Subculture]

Unfortunately the HK specs aren't always terribly accurate.

I tend to look at the can diameter and KV rating to assess what prop a motor can swing, has worked for me up until now. The cooments in the usesr reviews help too.

[invader1]

Thank you all for the suggestions. While money is not really an obstacle, I need to use what I have on hand. If it doesn't work well then I will buy something that will. For the moment I will try to use the motor as is.
Who knows-it may be fine and not burn up at all. Again-thank you for your support. I'm sure I'll be back with more questions.
                                                                                                  Invader1

[Subculture]

A prop of about 1-1.2" is going to be more appropriate for a high revving 700 size motor.