Overheating motor

[pribco]

While waiting for the glue to dry on the SkidaddleTOO I am making I have constructed a homemade "rescue boat." out of some left over luan. Painted and pollyied. Looks like a WW2 landing craft.

24" long--

Runs terrific but motor really overheats. Motor is an Kyosho Lemans Stock 05. The number 1200 in on the package-rest is in Japenese.

Prop is 1 3/4 inch-- It is the CEN 42mmx1.4

Battery is standard 1500 ahm.7.4 vts.

No cooling system.

Question--could this be a 6 volt motor<

Is the prop to big??

The motor (left over from long ago) seems to be for a car--should I get a marine motor?

Any advice appreciated.

Bill

[Fluid]

The prop is way too big for that motor in a non-planing hull with submerged drive. Go to something like an x430 (1.18" diameter). It is a 6-cell (6 x 1.2 volts) motor designed for a car, but we used to use them in boats all the time. The biggest problem here is far too much prop.


.

[pribco]

Fluid-thanks, I sort of suspected that-to bad because it moved pretty smartly before overheating.

As a follow up-

1. When I go to the smaller prop, will I see a fall off in preformance??

2. Should I go with the Dumas 6v, 10,000 rpm motor or the Aquacraft 540 brushed motor?-if so what prop??

Thanks, Bill

[Fluid]

I'm not familiar with either motor. You can expect a fall off in performance with the smaller prop, how much is hard to predict. A prop no larger than 1-3/8" in diameter, the Octura plastic x431 is pretty good.

.

[Alexgar]

That's a onroad motor with a 45 47 mm prop some nice bl motors would overhead with that Prop load I say a 531 prop on 25000 would move a small hull well but a heavy hull needs a low kv big prop

[pribco]

Alexgar-thanks for the reply but I don't understand.

With the motor that is installed, what prop--I tried a smaller one this morning in the bathtub and seems to run cooler.

OR--should I put in the Dumas motor (10,000RPM--if so what prop-

OR - the Aquacraft (brushed,540) If so what prop?

Thanks, Bill

[Alexgar]

sorry i was posting on a phone not to easy
i would go with the aquasport motor and a octura x531 or a stock prop from a blackjack nitro ive had good luck with both of these in smaller hull

[pribco]

Alexgar--when you say low kv, what do you mean??

Why the Aquacraft motor instead of Dumas?--just more rpm/torque etc??

I am sure you realize this is not a plaining boat--picture Omaha Beach, 1944

[Alexgar]

Kv means rpm per volt a high torque motor with a big prop or a faster motor with a smaller prop choose one but a fast motor with a big prop will burn up in. No time

[pribco]

Thank you Sir--put the Aquacraft in this afternoon--will give it a test run in the bathtub later. Put a 1.1/4 " prop on-

Will order the prop you sugested next time I order from Offshore, but p/h kills a small order.

[Alexgar]

yor can buy the proboat nitro prop at the hobbystore for like 3.99

[pribco]

Thanks to everyone--last night put in the Aquacraft motor and a 1 1/4 " prop--tried in bathtub the morning--what a difference--Pulls twice as hard, motor stays cool for a steady 5 min run at full speed. Water was almost pushed over the side of the tub.

Would go to the lake and try today but income taxes need to be done-(at least the $ will be wisely spent!!!)

My trophy bride thinks I have lost it--a 70 y/o man playing with boats in the bathtub--at least it's not a rubber ducky!!