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[crock]

Hi, I've been reading and was fairly convinced that a Graupner 700 12V was the way to go BUT, I've seen a few other suggestions since on this wonderful forum     Many years ago (~30) it ran on a graupner geared motor turning an X70 or X75 prop.  It came up onto the plane nicely.  The old motor died a few years back and the boat was put into mothballs but now living on an estuary (The Comarty) I have some water to play with.  I had aquired 2 different motors, one a decaperm geared which pushed a X75 prop, ok but not quite on the plane, I then put in a 540 type  motor which a trader had sold me at a model show, said it would be great for the Perkasa if I'd built it light enough ! ( Fiberglass hull).  The 540 came wired with suppressors, cooling and flux ring.  It's not doing the job.
Any advice please, I'd like to stay on 12V or possibly 14.4V.   I've seen mentioned the Deans Kestral as well as motors from MMB and Modelboatbits. 
The shaft is a heavyish duty flex, probably meant for an ic engine, I'd rather not rip it out unless .......  it would take most of the bottom of the boat.


As an aside I've just finished the Matchbox Corvette, runs on 6V and a Robbe Navy geared motor (abt 30yrs old !!) oh, and an X50 prop.


Mike

[Perkasaman2]

A single graupner  700 BB 12v (model 6317) on a 45x will probably be fine if you want a brushed motor. This motor has an inbuilt fan to assist cooling which is helpful. 

[malcolmfrary]

The motor does need matching to the prop to convert the power into water moving fast enough, so a 540 will need a smaller prop to get a narrow column of water moving fast, rather than a wide one moving slow..  I usually associate flux rings with slower revving motors, as in tugs and suchlike where torque is wanted over revs.

[crock]

Hi Chaps, thanks for your answers.  This confirms what I was thinking, thank you. 


 Re the 540 motor I did find it rather strange that it had a flux ring on, I tried it with an X30, X35 and an X37.5 but not much difference in the performance.  It did make my batteries very hot though.

[crock]

Hi Chaps,


At long last, why does life have to be so busy ???, #I've run my Perkassa with the Graupner 700BB 12V, X45 prop and some fairly tired old 12v NimHs, much more fun.  Very pleased so thanks for all the advice. 


Just saving up for two new 7.2V NimHs.


 

[crock]

Update on my previous posts and hopefuuly a pic of my Perkassa running on its' 700BB and 10 somewhat tired NiMH cells in a bit of rough weather off the bottom of the garden.   It could do with a bit more waterproofing !!   


Since my new batteries and charger turned up it's been too rough to launch 

[BigTam]

Use a Hectoperm, get 35 running time and planning.