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[timgarrod]

Afternoon All,

I've after a bit of advise on props on my Robbe norderney.

The motors are the old robbe red gearbox type and sticker say 6v - 8v and had 3 bladed 30mm props. I know the newer gearboxes are ok on 12v but these get hot so going to run on 6v. I was wondering if these props with be better for it than the 3 bladed currently on it.

[Big Ada]

I never use Gearboxes, just less thumb.

[John W E]

Hi all
Are these the gearbox and motors in your model?  I snaffled this photograph off the web.    If so, they are either a Graupner 500 or 600 motor on the gearbox and they are rated at 7.2 operating volts for best performance.  The photograph of the proposed props that you are hoping to exchange - the motors and gearbox should handle these no problem.   Just a thought and a bit of information; the powers that be that taught me Electronics used to say the higher the voltage a brush DC motor runs at - it makes it more efficient.  Therefore high rpm in an electric motor doesn't give you much torque but stick a gearbox on of the correct ratios; keeping the motor rpm high and the output shaft low rpm gives you plenty of torque with an efficient motor.

So no need for thumbs

john

[canabus]

Increasing the number of prop blades will increase the load on the motors.

[timgarrod]

cheers all, going to leave the prop and try it on 6volt. it the noise the gearboxes (typical problem with the robbe one's) and if the proformace is poor i try the others.

[John W E]

the noise the gearboxes (typical problem with the robbe one's)


two words

silicone grease

does wonders for noise

[RAAArtyGunner]

Increasing the number of prop blades will increase the load on the motors.

As well as an increase in speed, Yes/No ????