I think Ashley's comment that some ESC's are not as whiny as others is the key, but it's primarily the motor that whines rather than the speed controller.

In order to control the speed of the motor it's necessary to supply it with a variable voltage. Old fashioned 'Bobs Board' voltage regulators did just that and supplied a steady DC voltage, at the expense of being inefficient by generating heat in the resister. However because the motor was getting a steady DC voltage it did not whine.

Modern electronic speed controls switch the battery voltage on an off at high frequency, maybe 1000 cycles per second or more. In each cycle there is a period of time when the voltage is on and another when it is off. The motor is effectively powered when the voltage is on and its inertia keeps it going when it the voltage is off. The longer the proportion of on to off, the faster the average speed that the motor runs at. In practice the motor is continually accelerating and decelerating at high frequency rather than running at a true steady speed.

A modern speed controller more efficient than a 'Bobs board' as there is less power wasted. However the rapidly changing voltage excites the motor and causes the whine. I dont know exactly which bit of the motor is responding but it is down to the design and construction of the motor and the frequency that the speed controller operates at. The whine is usually worst at the low speed end of the throttle range, when there is also less nose from the prop shaft and universal coupling to drown it out. You could try to soundproof the motor by enclosing it in some form of enclosure but as Ashley says, this can result in overheating and sometimes just amplifies the noise if some part of the structure resonates with the motor.

The majority of my models have Graupner speed motors and Mtroniks speed controllers, mainly on a better the devil you know basis, but also to provide some degree of interchangeability. The level of whine from that combination is just about acceptable, but I must admit it is sometimes irritating. Other modellers will have experience of other combinations of equipment. I seem to remember Dave Milbourn having some words of wisdom on this topic and I am sure he will be along soon with some good advice.

Edited By Gareth Jones on 06/10/2013 08:30:24

Not going at full speed, but a taster of the beast on the pond.

No, dont think so….. Ashley

looks very nice………

I am still using my original Supermarine Special, 51 years after it first went in my Crash Tender. I also have a Double Special in an MTB, a Target, a Standard and a Meteor, the last two mint and boxed and lined up for a couple of straight runners.

They go with with a selection of Orbit, Kako, S.E.L., Frog and Multums. I collect old electrics as old Diesels are silly money and steam is impossible.

I only use R/C in yachts, because of the reeds round local waters where there's the space for sailing. Oh and the yacht is a Veron Veronica and, soon, a scratchbuilt Victorian Cutter.  The 2 Pre-War Marbleheads are vane steered, when I go to a pond with an edge all round. It's great exercise.

I also don't posess a mobile phone and my cars are 55, 40 and 24 years old

Martin

Edited By Martin Field 1 on 12/05/2014 17:09:39

Ashley,

you are right of course and my wife's old one is always plugged (with car charger) firmly in my mitts when I go abroad (ie, outside). She can find me on it, but only friendly lorry drivers can reach her at my behest, whatever I try.

Meanwhile, hers never stops warbling , trilling and trumping all bloomin' day and night advising her of ebay bids, endings, Facebook posts, blah, blah!

My battery drill whines when it's on partial speed. Or is it the speed controller that whines?

Martin