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Author Topic: Is this OK?  (Read 1911 times)

Nordsee

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Is this OK?
« on: November 15, 2010, 01:57:25 PM »

I have a Speed 400, 4.8 volt. I want to use a 5 or 6 cell drive battery with suitable ESC. That will be 6 or 7.2 volts. Will that be OK with that motor? I know it is a silly question, but how will the motor react to such a high voltage?
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TomTheKraut

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Re: Is this OK?
« Reply #1 on: November 15, 2010, 03:05:53 PM »

Hi Nordsee,
... will the motor drive a fully submerged prop (i.e. Mini-ECO boat) or a surface drive (i.e. Mini-Mono or Mini-Hydro)?
Or are you planing on pushing a scale boat?

5cells should be ok even without water-cooling the motor. 7,2V will most definitely require cooling and is a typical set-up for Mini racing...
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Nordsee

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Re: Is this OK?
« Reply #2 on: November 15, 2010, 04:16:11 PM »

A submerged prop, 30mm. Graupner plastic. It is a sport boat, an Aerokits I think,very old, about 1978. A rebuild.
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Nordsee

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Re: Is this OK?
« Reply #3 on: November 15, 2010, 04:56:55 PM »

Here is a photo, if I can get it uploaded!!
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andrewh

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Re: Is this OK?
« Reply #4 on: November 15, 2010, 05:07:16 PM »

Hi, Nordsee

The broad answer is usually yes, but in this case yes - if you use a small enough propellor :}

The rules of Speed 400ing are that the current draw must not exceed 10A for more than a moment - so what matters is the load.

I would not try this setup with a prop bigger than 20 to 25mm dia.  There is a sweet 30mm racing graupner prop  - but it would need to be reduced in diameter.

Generally the "voltage" on a Speed motor is telling you about the diameter of wire inside, but on the 4.8 version is is pretty nearly true :} The S400 4.8 is a real screamer and was aimed at low voltage, high current applications (it comes out of 2-cell screwdrivers)

Try it, feel the motor after a minute - if you can touch it give it another minute
andrew
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Nordsee

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Re: Is this OK?
« Reply #5 on: November 15, 2010, 05:19:55 PM »

HHMMMMMMM!!! So really I should go out and order another motor!!( The nearest Model shop is a 60 mile round trip) Or maybe a "Cooking" 380? How about the Speed 400 in 6 or 7.2? If there are such motors!!
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dreadnought72

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Re: Is this OK?
« Reply #6 on: November 15, 2010, 06:02:55 PM »

That rudder looks suspiciously back-to-front to me!

Andy
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Enjoying every minute sailing W9465 Mertensia

dodgy geezer

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Re: Is this OK?
« Reply #7 on: November 15, 2010, 07:37:47 PM »

Looks like a NorStar Osprey, not an Aerokits.

It should be 19" length, beam 6.5" In the 1972 KK handbook it was 3.22....
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Nordsee

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Re: Is this OK?
« Reply #8 on: November 15, 2010, 09:23:14 PM »

The rudder has no servo, so it turns around! The sizes are correct, so hello Osprey! She is called "Soulan",( Wild Goose in French), which was the name my Father gave to his last boat ( Full size) that he built. Is my choice of motor about right? I don't want an out and out speedster, just a lively boat.
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TomTheKraut

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Re: Is this OK?
« Reply #9 on: November 16, 2010, 05:55:31 AM »

Hi Nordsee,
... if you can keep her lightweight, a 400/6V running nominal voltage or 7,2V and turning a small prop should give enough push.
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dodgy geezer

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Re: Is this OK?
« Reply #10 on: November 16, 2010, 03:20:21 PM »

A page of the 1972 KK handbook, showing the original and its sister ships...



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Nordsee

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Re: Is this OK?
« Reply #11 on: November 16, 2010, 08:09:11 PM »

Thanks for the picture. I love the prices!! They were really attractive models. I notice that the Osprey is the only one with a 3 bladed propellor.Suppose because the others had IC motors. If I remember , the plan showed a .5cc diesel as power.Any chance of finding plans on the Net or even here? Would be nice to buld another one !! Wave Rider or Wave Princess look specially tasty!
  Thanks Tom, I think I will get a 6volt 400, keep it undramatic!
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Nordsee

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Re: Is this OK?
« Reply #12 on: November 21, 2010, 08:37:44 PM »

Looking through my junk boxes ( I have several of them) I discovered a Mabuchi 380 se. It came from a Tamiya Holiday Buggy from way back when. ( They are back on the Market again) This used to run on 6 cells, so it is going in with a Graupner 2 blade plastic prop , 30mm dia, I will post photos when it is running, or bursting into flames!!
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