I'd start with something like a Graupner Speed 600 ECO, 7.2v or 8.4v pack and a 3-blade 30mm or 35mm prop. Cheap and cheerful.
Dave M

We could do with a little chart of thrust equivalents, old i/c or glow engines verses modern electric, as not only does this topic come up now and then, but others must convert old boats to electric on a try-it-and see basis with various success.

Ashley. Not much use I am afraid as no old i/c boats to play with.

Have you got a picture of Moonglow, please?

Just for interest

Bob

Colin, rather than a full list, what about a rough guide as to the output in watts of a typical 1.5cc glo or 3cc whatever, and possibly at what revs (although that might not be so useful), and then in theory a similar wattage electric motor could be fitted and so the performance should be on a par with the afore mentioned smelly i/c motor ??

is that reasoning right?

Ashley

Paul. the smell..hmmm

fast is the point here…how fast … is a 1.5cc glo a very powerful beast? if so a 3.5cc must be stupendous…or is it?

Colin, you never know, interest may be high…but how to find out the interest? I would have thought it would be worth a page in a special devoted to older boats? see below, if using old plans.

I found a table, possibly by Vic Smeed, of "current" electric motors …Orbits and other exotica, in one old mag at home. very interesting if building a boat from an old plan and it says "orbit 805" for the motor…look it up and find a modern equivalent!

just reread the thread beginning… a table of equivalents surely is a MUST if publishing a special on old plans??

Ashley

Edited By ashley needham on 25/04/2012 14:00:14

Well done Ashley, will you be covering areo and diesel engines upto 10cc

I can see it now "name the bearing material used on an Arbutnot 3.249cc Hi-power special from 1930"

If a sheet of i/c engines was passed my way i SUPPOSE I could see if there was any generalisations one could make, and compare them to , say, the common Graupner brushed motors in terms of power…supposing the power output of the i/c engines was mentioned…but.. supposing a 1.5cc diesel and a GP500 on 7.2v produced approximately the same max power.. does this mean the performance would neccessarily be on a par when fitted to a Moonbeam skippy special boat?? or would there be other factors, like revs and prop sizes and weights that would affect the performance and so stop a simple like for like power comparison taking place?

I am guessing that a 1.5cc motor and a small fuel tank is fairly light, and would out power/weight a brushed motor and Nimh battery pack AND esc???

Ashley                 has no spare time as it is

Edited By ashley needham on 26/04/2012 09:21:05