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Author Topic: Graupner 400 Series  (Read 4194 times)

rem2007

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Graupner 400 Series
« on: September 23, 2009, 10:39:20 pm »

Just wondering if anyone has used any of these in their boats.

http://www.cornwallmodelboats.co.uk/acatalog/graupner_1794.html
http://www.cornwallmodelboats.co.uk/acatalog/graupner-3320.html
http://www.cornwallmodelboats.co.uk/acatalog/graupner-3320.html

I was thinking of putting one in my RTTL Vosper, since I brined the other one, and I see the dimensions are the same as a 385 but would give a bit extra and get her up on the planes to scale speed.

Robert
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Shipmate60

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Re: Graupner 400 Series
« Reply #1 on: September 23, 2009, 10:50:42 pm »

All of them are high speed motors which will prefer a small racing prop.
The lowest stall current was 21 amps and the 2 highest were 40 amps.
That is a very high consumption for such a small motor.

Bob
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FullLeatherJacket

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Re: Graupner 400 Series
« Reply #2 on: September 23, 2009, 11:13:00 pm »

Robert
I run a 7.2v Speed 400 on 6 x AA cells in a 20" Swordsman, using a Prop Shop 2 blader. I think it's a 1" diameter prop - certainly no bigger. Not a problem with a 10A ESC.
Hope this helps.
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Shipmate60

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Re: Graupner 400 Series
« Reply #3 on: September 23, 2009, 11:24:24 pm »

Bet you wouldn't run it on a much bigger prop though.

"suit yourself   :D"

Bob
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Martin (Admin)

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Re: Graupner 400 Series
« Reply #4 on: September 23, 2009, 11:44:32 pm »


I put a Graupner Speed400 6v in my Baby Severn conversion... a just tad too powerful!
 Building a 2nd one with a Speed400 7.2v
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Shipmate60

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Re: Graupner 400 Series
« Reply #5 on: September 23, 2009, 11:47:02 pm »

They are good small high revving motors.
But can only handle small or fine pitched props to allow the revs.

Bob
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FullLeatherJacket

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Re: Graupner 400 Series
« Reply #6 on: September 24, 2009, 08:22:43 am »

Bet you wouldn't run it on a much bigger prop though.

"suit yourself   :D"

Bob

"Why, certainly not, Stanley! The very idea...........Hmmph!"
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rem2007

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Re: Graupner 400 Series
« Reply #7 on: September 24, 2009, 09:05:31 pm »

Hi guys,

Thanks for that, going for one to bung into my RTTL Vosper, as the 385 just doesn't get her up to scale speed, running the 7.2 power pack, which ran for ever on the 385, but will probably loose some running time, but I'd sacrifice the time for a bit extra speed.

Robert. :-))
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malcolmfrary

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Re: Graupner 400 Series
« Reply #8 on: September 25, 2009, 10:41:56 am »

Agree with all the comments about small props to let the revs build.
Martin - if you stick a bit of aluminium sheet under the stern of your little Severn to act as a trim tab, it will magically run fast and level.  I had the same symptoms on my Lotse when I accidentally ran a 6V Speed 400 on 7 cells in it.  The water flow is being grabbed by the indents for the original props and probably by the radiused bottom corner of the transom.
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Martin (Admin)

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Re: Graupner 400 Series
« Reply #9 on: September 25, 2009, 11:44:05 am »


I just moved the battery way forward Malc  :-))
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malcolmfrary

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Re: Graupner 400 Series
« Reply #10 on: September 25, 2009, 11:54:10 am »

I just moved the battery way forward Malc  :-))
That which works is a good solution.  I still think it will go faster with the back end sorted hydrodynamically.  What does the shift of battery do at the static trim?
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Martin (Admin)

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Re: Graupner 400 Series
« Reply #11 on: September 25, 2009, 03:48:20 pm »


The chine ride is now correct but it's a bit loolopy in tight corners but that's because the battery is to high (now above the motor
and because it's doing a scale speed of Mk 1.
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