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Author Topic: Speed 400 motors  (Read 2997 times)

Dekan

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Speed 400 motors
« on: April 24, 2011, 03:52:46 PM »

My Graupner 7.2 v Speed 400 died after only running about 5min at hi speeds off and on (7.4v. battery).  Is this normal for a Speed 400 in a boat..  :((

I have looked a similar installations on plans and kits.... none of the kits I have seen have any more ventilation than the Deans marine RTTL I am running it in.

The prop shaft alignment seems ok and the drag does not seem excessive... :-))

Next step is water cooling... but that seems a bit over the top just to run small launch flat out for a couple of a minutes  at time...Any thoughts...
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Dekan

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Re: Speed 400 motors
« Reply #1 on: April 24, 2011, 08:10:42 PM »

I have just had phone call from friend...he thinks that I'm barking up the wrong tree.... he reckons the standard prop with the kit is way too big diameter (32mm approx) and the pitch is too course..

So I'm now looking for 26mm lowish pitch prop...
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gregk9

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Re: Speed 400 motors
« Reply #2 on: April 24, 2011, 08:35:32 PM »

yes, could well of been the prop diameter. i have 3 x speed 400's in my torpedo boat and they run 22mm props with ease and still get a decent speed and they run off an 11.1v lipo !
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Steve. G.
Treasurer & Membership Secretary:  Chasewater Model Boat Club
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triumphjon

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Re: Speed 400 motors
« Reply #3 on: April 24, 2011, 09:21:52 PM »

ive recently had a similar problem , having a pair of 6 volt speed 400s in a 28" huntsman , running on 7.2 volts the port motor started smoking ! the model has now been remotored with a pair of perkins 480 long can motors to which ive fitted cooling jackets , which to date seem fine , they are running on a single 7.2 volt pack and turning 35mm 3 bladed props !
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Dekan

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Re: Speed 400 motors
« Reply #4 on: April 24, 2011, 11:00:59 PM »

yes, could well of been the prop diameter. i have 3 x speed 400's in my torpedo boat and they run 22mm props with ease and still get a decent speed and they run off an 11.1v lipo !
Greg, where did you get the props from?
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nick_75au

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Re: Speed 400 motors
« Reply #5 on: April 25, 2011, 01:16:42 AM »

There are quite a number of different Speed 400's, ranging from very hot to very mild, the voltage on them indicates the way its wound with the 4.8 volt being the fastest with a few turns of fence wire and the 12v being wound with many turns of thin light wire.

Nick
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Dekan

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Re: Speed 400 motors
« Reply #6 on: April 25, 2011, 09:16:03 AM »

7.2V is the highest voltage easily available in the UK.... I have never seen a a 12V one..
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gregk9

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Re: Speed 400 motors
« Reply #7 on: April 25, 2011, 10:23:36 AM »

I had the props from SHG marine supplies.  they offer a superb mail order service and have a good downloadable online catalogue.

I used these props as they were recommended for my PT  596 boat, they infact supplied the complete drive system for my build conversion from the Italeri kit


http://www.shgmodels.com/acatalog/
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Best wishes.

Steve. G.
Treasurer & Membership Secretary:  Chasewater Model Boat Club
http://chasewatermbc.blogspot.com/

nick_75au

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Re: Speed 400 motors
« Reply #8 on: April 25, 2011, 01:16:40 PM »

I think your right, I'm at my Inlaws place on my laptop, so don't have all my motor data to hand, I assumed there was a 12 volt one like some of the other series motors :embarrassed:

Ive attached a screenshot showing many different flavours of "400" from Mabuchi

Nick
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Dekan

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Re: Speed 400 motors
« Reply #9 on: April 25, 2011, 01:20:58 PM »

Thanks guys... As a toy airplane pilot..I'm completely out of my depth when it comes to boats {-)
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andrewh

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Re: Speed 400 motors
« Reply #10 on: April 26, 2011, 12:49:43 PM »

Hi, dekan

As a toy airplane pilot you will know that any of the S400 family will take 10A continuous (max) and die if taken beyond that

I run S400s in fast boats (without water-cooling) with as small a prop as I can get and let them scream their little hearts out.  The best prop (originally reccommended by George Turner) seems to be the Graupner 2mm racing prop of, I think, 25mm dia.

I won't shout, but Its the Amps that kill motors, not the volts
andrew
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Dekan

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Re: Speed 400 motors
« Reply #11 on: April 26, 2011, 05:57:33 PM »

Andrew... I have never used a S400 in any kind of model....

All my planes use brushless motors...but if you mention brushless or lipo to the average boat club member they either glaze over or make the sign of the cross :}

Unfortunately my boat has 4mm shaft
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colin-d

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Re: Speed 400 motors
« Reply #12 on: April 27, 2011, 11:36:13 AM »

the range of brass props from Raboesch some of them go down as far as 20mm in the M4 thread

so there would be a suitable prop for you in that range....
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Dekan

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Re: Speed 400 motors
« Reply #13 on: April 27, 2011, 05:04:08 PM »

Thanks Colin... but.... they are a bit too expensive for the job in hand :((..The prop would cost more than the motor which takes a bit pf getting used too :}
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andrewh

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Re: Speed 400 motors
« Reply #14 on: April 27, 2011, 05:09:48 PM »

Dekan

Suggestion - get hold of a few 4mm cheap plastic 2-blade racing props around 30 to 35mm dia (howes were selling them for pennies at shows)

make a 4mm "bung" to go in the threads - use a divider to score the blades nice and circular about 25mm dia
score halfway thru and snap off, or cut off with razor saw

finish with file and sandpaper with prop fitted to shaft and running

Bob is avuncular relative
andrew

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HUNTER

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Re: Speed 400 motors
« Reply #15 on: April 27, 2011, 05:42:36 PM »

Hi Dekan,
A rule of thumb for that size motor is :

6v it is a speed 400 used in small boats and electric flight.
12v it is called a RS380 (3 pole) and RS 385 (5 pole) both tend to be used in a smallish boats.
All use the same can size and shaft Diameter though the RS385 tends to generally have a longer shaft length.
Hope this helps.
Graham at Hunter Systems
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Dekan

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Re: Speed 400 motors
« Reply #16 on: April 27, 2011, 07:38:51 PM »

Thanks to Andy's uncle and Graham  :-))..I have ordered a RS385 from SHG and a couple of small props to try..

I have got a smallish Robbe 3 blade prop to try (it looks fairly low pitch) So hopefully I should be able to get my RTTL   http://www.westbourne-model.co.uk/raf-crash-tender-11210-0.html   going  sometime over the weekend

I can probably use one of the many small lathes at work, to turn a prop down...it a question of finding a prop with enough pitch to give a reasonable speed without cooking the motor...

Hopefully the RS385 will have enough go to get the hull on the plane..    
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