Graupner Atlantic challemger

[Graeme LinskeyParticipant @graemelinskey75588]

Hi there,

I have the atlantic challenger but have no idea what size brushless motor to use for the jet drive I want optimum performance any idea on what size motors I should be looking at ? I have googled and read but everyone seems to have different thoughts

been suggested 1700kv or 1900kv no less than 1500 watts 4-6 cells

I have see you tube vids on the recommended 700 bb turbo motors but they don't look very effective

anyone tried a setup like this I have a pair of 750kv ntm motors installed 785 watts on 4 s but hardly gets up on the plane

I belive the jet drives need to rev to 15k to 25k to run at best

Regards

Regards

[Graeme LinskeyParticipant @graemelinskey75588]

[Dave MilbournParticipant @davemilbourn48782]

Graeme

Simple maths indicates that your 750 kv motors don't cut the mustard.

4S = 14.8v
So 14.8 x 750 = 11,100RPM
and 11,100<<15,000

6S would be within the stated range.

The 700BB Neodymium motors were the recommended ones when the model was introduced but brushless has changed the rules since then. On 4S the 1750 kv motors will spin at around 26K RPM unloaded.

BTW how did the test of the Graupner Schottel drive/Speed 900 @ 24,000RPM go (31 May 2016)? **LINK**

Dave M

[ashley needhamParticipant @ashleyneedham69188]

There was a chap on the pond ages ago with a Challenger, uprated, and he had endless issues with it.

I think if using the Graupner jet drives, then uprating only very modestly is the way to go, or the drives will go bust !!

​On this basis, slightly overmatching the theoretical max revs of the original motors should be the order of the day.

Of course if you have some other make of drive fitted the world is your Oyster.

Ashley

[Graeme LinskeyParticipant @graemelinskey75588]

Hi there,

A friend just gave me a pair of 1700kv inrunners I have on 4s will do 25500 rpm on 4s

The 820 bb race does 24000 rpm I have seen a few u tube vids with people running these and that,s perfect the 750 ntm out runners only do 4s

As for the Graupner schottel drives on the tug work perfect as it is a 3.1 reduction 8000 rpm and I have the hitec

digital servo that are programmed to max movement just over 180 degrees so can turn then into reverse

The Graupner 900bb torque would give me 6500rpm which is what my friends are useing but in the tug contest I won hands down

I have a

pair of brand new schottel drives mk 2 if any one interested

[Author]

Posts