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Author Topic: What size prop for a Torpedo 400!!!!  (Read 1479 times)

Popeye

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What size prop for a Torpedo 400!!!!
« on: March 04, 2010, 11:15:29 AM »

I don't have an ammeter  %) so could anyone help me with the following:-

(1) What maximum size three bladed prop should be used with a direct drive TORPEDO 400 working off 6 Volts or 7.2 Volts?
(2) What is the likely maximum amperage the motor would draw on full load?

The motor is to be used on a 45" LOA square rigger (deep drafted 'bathtub' hull)  to provide auxiliary power for use in emergencies only ('get me out of trouble' insurance), and will be wired for Forward drive only without use of a speed controller and activated by the 'Flaps' switch (ON or OFF only)  on my Tx.

Apologies if my terminology is found wanting :embarrassed:

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Popeye

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Re: What size prop for a Torpedo 400!!!!
« Reply #1 on: March 06, 2010, 04:56:12 PM »

I don't have an ammeter  %) so could anyone help me with the following:-

(1) What maximum size three bladed prop should be used with a direct drive TORPEDO 400 working off 6 Volts or 7.2 Volts?
(2) What is the likely maximum amperage the motor would draw on full load?

The motor is to be used on a 45" LOA square rigger (deep drafted 'bathtub' hull)  to provide auxiliary power for use in emergencies only ('get me out of trouble' insurance), and will be wired for Forward drive only without use of a speed controller and activated by the 'Flaps' switch (ON or OFF only)  on my Tx.

Apologies if my terminology is found wanting :embarrassed:

No response to my plea so far  - ain't there anyone in Mayhemland who could put me out of my misery????

Thanx in anticipation of a positive response


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Shipmate60

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Re: What size prop for a Torpedo 400!!!!
« Reply #2 on: March 06, 2010, 05:03:21 PM »

It depends if the "Get you home" includes fighting the wind etc or are you looking for more of a cruising motor?

Bob
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Shipmate60

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Re: What size prop for a Torpedo 400!!!!
« Reply #3 on: March 06, 2010, 05:07:23 PM »

The motor revs at 12600 which is fast so would suggest a plastic fine pitch prop about 45mm.

Bob
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Popeye

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Re: What size prop for a Torpedo 400!!!!
« Reply #4 on: March 06, 2010, 07:04:47 PM »

It depends if the "Get you home" includes fighting the wind etc or are you looking for more of a cruising motor?

Bob

Hi Bob,

I only need sufficient muscle to assist with bringing the head round when going about or gybing (wearing  or bearing away) so speed/power is not important.

PS. A TORPEDO 400 was provided for as an integral part of the hull construction and if I've made a Boo-Boo in respect of my choice it's too late  to substitute it for another with more 'grunt' , so I have to make do with what I've stuck myself with (Silly Billy that I am).
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malcolmfrary

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Re: What size prop for a Torpedo 400!!!!
« Reply #5 on: March 07, 2010, 11:44:44 AM »

Assuming that you are able to replace the 400 (its man made, so obviously it will need attention at some time) you could drop in a 385 rated for 15 volts (equivalent would be a 5 pole 400 rated for 15v), then use a prop of about 35mm (certainly no more than the can diameter) and a "normal" pitch.  I suggest not too fine a pitch because a fine pitched prop will offer more drag when not powering the ship.  On 6-7.2v current draw should be comfortably less than 5 amps.
Compared with the cost of a servo and microswitch, a modest ESC is not THAT much more, offers much more control, and will probably be more reliable.
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