HI pmdent
The 3639 and 3648 motors we run no water cooling and for ESC's we use Hobbyking car 60-100Amp.
These have an electric fan on top and have reverse as well.
You require a program card, but, they are easy to set up.
I can give you the set up I use on my cars and boats.
I have found 25% reverse power is a good safe setting.

Canabus - appreciate the offer of boat Plan swap - but I do not have any for the Aerokits Crash Tender - it is a rebuild from an original kit build around the 1950's by a distant relative. I am taking off "lines" by measuring model as I dismantle - effectively replacing complete cabin assembly and bulkheads, transom etc. which have been hit hard by woodworm. The model has been in freezer for 3 months to hopefully get rid of the blighters !!!

Mark and Canabus - many thanks for your responses - both confirmed my suspicions as I am converting to brushless motor - so will reduce prop angle down to about 10 deg with suitable clearance for propeller.

Also appreciate the motor setup detail suggestions as I am new to this are of modelling - have done RC sailing before.

One more query for now - can I get away without any watercooled motor or ESC on these type of setups for this si=ze model ? I am not interested in speed - just scale performance. Regards - Peter

HI pmdent

I finished building a Sea Hornet from the original plans and had them scanned as PDF file(also made up the frames).
I deceased the prop shaft angle and used a 32mm prop 2 blade with a brushless 28mm 1900kv 750 watt motor on 3S(11.1volts) 2650mah Lipo battery.
It will hit about 40mph on a calm day!!!!
The IC motor used back in the day were not as beastly as these brushless motors.
750watts = about 1 HP.

You crash tender is more suited to a 35mm 3639-1100kv on 3s 5800mah Lipo battery with a prop size 40-50mm 2 blade or 37mm 3 blade.
I have this setup on my camera boat and works well.
P.S. Would you be interest in a swap of plans.
I have the Sea Hornet, Swordsman and Sea Rover as PDF files.
With the PDF files you can change the boat size by going from 100% to 125% and the Sea Rover goes from 29 and 1/2 to 35 and 1/4.

HI Mate

The Aerokits were designed to have IC motors in them which had an excess of power, the steep propshaft was to allow the motor to be mounted fairly high in the hull to allow clearance for starting and adjustments to the motor.

If you are converting to electric, I would re drill the propshaft to about 8 / 10 degrees getting the motor as low as possible, but make sure there is good clearance for the prop to rotate. Depending on your choice of motor, a 45mm prop would need about 5mm clearance.

If you went the brushless route, the motors are very light so moving the motor towards the bow area would not be a problem, however the longer the shaft, the more whip in the inner shaft so you would need inner shaft bearings / supports to keep whip to a minimum

Hope this has helped

Mark