Vic Smeed’s Moonglow

[Colin BishopModerator @colinbishop34627]

I'm putting together another Model Boats special issue which will feature classic plan features from the past.

One of these is likely to be Vic Smeed's Moonglow which you 'can build in a couple of evenings!'.

Original suggested power was 1.5cc to 3.5cc diesel. The model is fairly lightweight and 35 inches long and about 9 inches in the beam.

Has anyone any suggestions on a suitable equivalent electric setup?

Colin

[Colin BishopModerator @colinbishop34627]

Suitable electric power

[Paul TParticipant @pault84577]

Hi Colin

If you are looking for something that modellers might have in their spares box then I would recommend the good old Johnson motor with a gel battery.

Paul

[Dave MilbournParticipant @davemilbourn48782]

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

[Colin BishopModerator @colinbishop34627]

Many thanks for the suggestions, duly taken on board!

Colin

[ashley needhamParticipant @ashleyneedham69188]

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.

[Colin BishopModerator @colinbishop34627]

Good point Ashley and it reminded me of the tables published in Vic Smeed's Model maker Annual in 1963 which gave very detailed technical data for all the IC and electric motors in boat use at the time.

I have scanned them in but the text is too small to reproduce in an album photo on here. It might be possible to publish it in the Special issue but would there be sufficient interest in something like this?

Colin

[Bob Abell 2Participant @bobabell2]

Have you got a picture of Moonglow, please?

Just for interest

Bob

[Bob Abell 2Participant @bobabell2]

Found Moonglow on this very interesting olde worlde website…..

http://www.vintagemodelworks.co.uk/?page_id=9

Full of other good stuff too!

Bob

[ashley needhamParticipant @ashleyneedham69188]

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 TParticipant @pault84577]

Ashley

When set up correctly IC don't smell…………….. they just go fast.

[ashley needhamParticipant @ashleyneedham69188]

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

[Colin BishopModerator @colinbishop34627]

And just who is going to do that Ashley – are you volunteering?

Colin

[Paul TParticipant @pault84577]

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

[ashley needhamParticipant @ashleyneedham69188]

never volunteer for ANYTHING!

Could be a mastermind subject.."and now Ashley, you have 3 mins on the subject of British tiddly engines up to 10cc from the year dot to 1960"

Ashley

[Colin BishopModerator @colinbishop34627]

I guess that's a no then…..

Colin

[Paul TParticipant @pault84577]

Hi Colin

I think its a big YES

If Ashley could do a special subject on mastermind on these engines then he is your man, in fact we have forgot all about the 2 stroke engines upto 75cc so you really do need Ashleys knowlage.

Paul

[ashley needhamParticipant @ashleyneedham69188]

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

[Gary DysonParticipant @garydyson81492]

Mornng all sorry to go slightly off topic but while we're on the subject of power output lists has there ever been a list of motor size to prop size printed for optimum perfomance ?

eg

grpnr 400 7.2v = 25mm prop gives X amps draw ?

Gary

[Colin BishopModerator @colinbishop34627]

There are recognised mpotor/prop combinations for competition classes but as far as scale is concerned it is a moving feast, there are just too many variables involved.

The usual practice is to draw upon previous experience, either your own or somebody else's! If you are building a kit then the manufacturer will usually have some suggestions otherwise the best thing is to find a boat of around the same size and type as yours that works well and use that as a guide.

There was an article in last year's Construction Special Issue of Model Boats which gave some suggestions on the subject.

Colin

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