Hi Phil
Good to hear you are an ex flyer. Had both gliders and powered IC models in the past and only stopped due to increasing age. You may want to consider obtaining motors and props from an ex drone flyer - one of the cheapo Chinese variety with four small motors and props. Avoid the brushed variety the brushless are far more reliable. They work great on a skimmer and due to changes in Government legislation are beginning to appear in large numbers on the second-hand market at very reasonable prices- some even have cameras and gimbals as an added bonus.
Dave976

Tnx JB and dave976, these props and lecy bits are a "means an end" for me ! - when I flew RC gliders, I once tried a messy diesel to get airborne and vowed never again. I do enjoy the filming side of RC Modeling so am determined to try and sort out this pulsing issue. rather than fall out of love with power altogether. ! So yes, I will follow yours and dave976`s advice on prop selection etc. (these cheap props do seem quiet flexible !). I will also go through all the connectors and leads as you say using the "trial by elimination" process !!!.
Thanks guys for the help and support !
Phil👍⛵

I have to agree. The motor is far too powerful for that model and the prop is causing the noise. On a public park this is likely to lead to a noise complaint so possibly best to be sorted. I suspect the pulsing is the motor reaching its max revs so a lower voltage and bigger coarser pitch prop would help. The skimmers on our club lake use 2200 size 800Kv motors on 2 or three cell Lipos with 8" two bladed props cut down from 10". Plenty of speed and power.

Hi Phil, could be a dodgy ESC/loose motor wire connection, (bullet connectors need to be tight) Could be something with the RX throttle lead connection. Is the ESC auto battery setting ? if not, is it set to the correct number of cells and battery type? Try testing each thing (ESC, RX) one at a time with another one of poss. Are you using a BEC from the ESC or a separate UBEC? Usually trial by elimination will pick it up.

I have around 50 ESCs of many types, and have never had that problem. If you can, start with the motor on another ESC and work backwards. The noise is the prop, only way to reduce that is to use a lower KV motor (around 800kv and a bigger prop) Mine is really loud with a 36/48 1450kv motor with a 9"x 6" prop (its' max load on 3s) (see recent vid). It can run a 5s but would require a 6"prop and would be ear splitting (over 100dB/29000 rpm). I've got it at a balance between speed and lots of complaints LOL.

Check your amps full throttle static with that prop, and if below the max A spec for the motor, prop it to just under rated max for the motor static, IE more pitch (it will unload when under way) That's as quiet as you will get with a 3s. Try going to a 2s and a higher pitched prop which will reduce the noise, (2s will give the motor more torque for a bigger prop at a lower tip speed. Check amps as above. A 2s 40c will give you more power as well if required,- you don't have to buy a bigger motor to get more power, just up your C rating)

JB