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Author Topic: Need for(a bit of) speed...  (Read 6535 times)

das boot

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Need for(a bit of) speed...
« on: September 26, 2009, 12:09:22 PM »

Just bought one of these hulls from ebay http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=140348367856&ssPageName=STRK:MEWAX:IT#ht_500wt_1182 to build and play with whilst I'm drilling and filing 500odd flood slots in U-Flak1...   %%

Your advice gentlemen please, on the best motor/battery/shaft/prop combination to start from? No li-poly things, just common or garden nicads please...and a submerged shaft, I don't want anything too technical.

Ta

Rich

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Shipmate60

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Re: Need for(a bit of) speed...
« Reply #1 on: September 26, 2009, 01:26:38 PM »

On 7.2 volts a standard 540
Above 7.2 volts a 550
More exotic and expensive motors Graupner 70 BB Turbo, but you will need to increase the voltage from that stated on box ie a 9.6 volt motor runns quite happily in 14.4 volts but would recommend watercooling.
Flexi shaft
2 blade racing prop, not sure depending on motor.

Bob
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das boot

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Re: Need for(a bit of) speed...
« Reply #2 on: September 26, 2009, 01:46:12 PM »

By heck Bob, there's handy, then...I've got a 70BB Turbo doing nothing. 14.4 volts...that's..err...12 cells? (I wish I payed more attention to the maths teacher at school all those years ago!)

Prop size...how about starting off with something like a 40mm two blade? Or even a 45mm?


Thanks,

Rich
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Shipmate60

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Re: Need for(a bit of) speed...
« Reply #3 on: September 26, 2009, 02:10:02 PM »

Rich,
I would wait a little for some of the Fast boys to advise on specifics.
I thought you only wanted (a bit of) speed!!!
With over 12 volts you will need either an expensive ESC or heavy duty microswitch.
And don't forget the heavy wiring to take the power.

Bob
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das boot

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Re: Need for(a bit of) speed...
« Reply #4 on: September 26, 2009, 03:39:05 PM »

Thanks Bob, the hull won't be here until Tuesday/Wednesday, so there's plenty of time for the racers to pass their comments on your choice.

Bit of speed...hmm, that outrigger frightened me so much I sold it before I'd even got it wet, but this one is just for fun(says he looking at Electra's website) It should be a bit quicker than U-Flak1 will be...

I hadn't given any thought yet to controlling the beast...wonder if the ActionMan can come up with something to slow it down?


Cheers Bob,

Rich
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Shipmate60

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Re: Need for(a bit of) speed...
« Reply #5 on: September 26, 2009, 03:47:35 PM »

Something like:

P98 HIGH-POWER ELECTRONIC SPEED CONTROLLER
54.00 Incl VAT   
P98 was developed primarily at the request of our Australian agents, Darke Horse Model Supplies, to use with their fan-cooled, planetary-geared 785 motors. These run on power supplies from a humble 12v up to a mind-boggling 20 cells (30v+), although their current consumption is relatively modest. Our Design Consultant, Dr Tim Fawcett, has broadened the specification and also included some very useful features, with the result that the P98 is probably the most �controllable� speed controller on the market anywhere in the world. Specifications are: Motor voltage 12v Min; 32v Max Motor Current 30A Max Continuous; 140A Surge Rx Supply voltage 5.0v Min/6.0v Max User-selected functions (via on-board DIL switches): 1) Standard/Offset neutral transition speed 2) Linear/Non-linear acceleration curve 3) Standard/Extended speed range 4) Normal width/Wide neutral (dead-band). Case size 74mm x 50mm x 28mm (+30mm for heat-sink fins). Screw terminal connections. Accessories (Available separately) P99 In-line 5v Voltage Regulator P98W Heat-sink water-cooling set

Bob
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Shipmate60

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Re: Need for(a bit of) speed...
« Reply #6 on: September 26, 2009, 03:49:23 PM »

For the 700 on additional voltsge you will need to water cool the motor.

Bob
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das boot

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Re: Need for(a bit of) speed...
« Reply #7 on: September 26, 2009, 04:02:16 PM »

That is an animal of an esc...50? Ouch... <:(

Watercooling...will a few wraps of copper tube be sufficient Bob, or do I need anything more sophisticated?


Rich
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Re: Need for(a bit of) speed...
« Reply #8 on: September 26, 2009, 04:24:52 PM »

Rich, copper tube will be fine, at least 5 turns.
You could still go the 540 route at 7.2 volts, wont be a "beast" but will look fine.
If it is  just a fun boat microswitches will give you full ahead and full astern, but for control you will need a fused high power speed controller.
Speed don't come cheap!!!

Bob
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das boot

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Re: Need for(a bit of) speed...
« Reply #9 on: September 26, 2009, 04:41:29 PM »

You're not kidding Bob.... :D


Thanks for the advice, it's much appreciated.

Rich
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Shipmate60

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Re: Need for(a bit of) speed...
« Reply #10 on: September 26, 2009, 04:47:07 PM »

No problem Rich, but would be better getting some info from the Fast Electric Lads.

Bob
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das boot

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Re: Need for(a bit of) speed...
« Reply #11 on: September 26, 2009, 04:48:55 PM »

I be stood standing by for any advice/comments/criticism/general mickey taking Bob...


Rich
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Re: Need for(a bit of) speed...
« Reply #12 on: September 26, 2009, 05:08:32 PM »

As in Static or Dynamic diver?

Bob
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das boot

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Re: Need for(a bit of) speed...
« Reply #13 on: September 26, 2009, 05:45:23 PM »

With the amount of ooomph you're talking Bob, dynamic I guess!!!



Rich
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andyn

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Re: Need for(a bit of) speed...
« Reply #14 on: September 26, 2009, 06:54:54 PM »

Excuse me but why are we talking about prehistoric motors? This is a 'fast' electric hull {:-{

This is what you want Rich:

http://www.r2hobbies.com/proddetail.php?prod=rcps81711&PHPSESSID=dc02ecf3576f248db4a3cf4ceb810ce2

http://www.r2hobbies.com/proddetail.php?prod=pba1517007
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Shipmate60

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Re: Need for(a bit of) speed...
« Reply #15 on: September 26, 2009, 07:13:32 PM »

Because of the first post:

"No li-poly things, just common or garden nicads please...and a submerged shaft, I don't want anything too technical."

Bob
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das boot

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Re: Need for(a bit of) speed...
« Reply #16 on: September 26, 2009, 07:15:21 PM »

And also because of the price tag!!



Rich
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Bill D203

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Re: Need for(a bit of) speed...
« Reply #17 on: September 26, 2009, 11:50:20 PM »

Hi Rich
A fast electric boat seems fine but a nice 21 glow plug engine would pull that boat around all day. NO ESC to buy. NO motors to burn out and when the lake gets a bit of weed on it the prop will chop it up and spit it out. Unlike a electric set up.
Pitty you got rid of your Electric Hydro rigger I would have like to had a go with that.
However I hope you enjoy building your new boat and may it give you many hours of FUN ! Thats the main thing. :-))
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das boot

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Re: Need for(a bit of) speed...
« Reply #18 on: September 27, 2009, 08:12:55 AM »

Hi Rich
A fast electric boat seems fine but a nice 21 glow plug engine would pull that boat around all day. NO ESC to buy. NO motors to burn out and when the lake gets a bit of weed on it the prop will chop it up and spit it out. Unlike a electric set up.
Pitty you got rid of your Electric Hydro rigger I would have like to had a go with that.
However I hope you enjoy building your new boat and may it give you many hours of FUN ! Thats the main thing. :-))

Hello Bill,

Our local lake has an ic ban mate,  :police: they are only allowed at official race meetings, so for playing it has to be leccie power.

That hydro frightened the life out me just sitting on the bench, I didn't dare put it in water!  :embarrassed:  Hopefully this will be a lot tamer.....

And it's not a 700BB Turbo motor I thought I had, don't know what I did with that, more's the pity.   >:-o  Still, they don't seem to be that expensive...do they?


Rich
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nick_75au

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Re: Need for(a bit of) speed...
« Reply #19 on: September 27, 2009, 10:09:22 AM »

If you used a geared 2/3:1  700 motor a 25 amp m-tronics or blue or similar would be sufficient on up to 50 mm brass props and give you adequate speed.
You would want to run the maximum voltage of 12 volts, equivalent to 10 Nicad/Nimh cells, pity the M-tronics cant run 2 6 cell packs in series.
A club member runs a direct drive 600 and 40 mm prop on 12 cells in a similar sized boat using one of the blue speed controllers, it gets up on plane and is quite nimble, It will never compete with a FE but FE is not what you are looking for Im reading.
I can highly recommend the ACTion units mentioned earlier as the "Australian Agent" is just around the corner and his Perkassa flies
Nick
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andyn

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Re: Need for(a bit of) speed...
« Reply #20 on: September 27, 2009, 12:11:19 PM »

No li-poly things, just common or garden nicads please...and a submerged shaft

Fine then, use the nicads.

This thing will be terrible on a submerged shaft.
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das boot

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Re: Need for(a bit of) speed...
« Reply #21 on: September 27, 2009, 04:03:54 PM »



Andy, what sort of drive should I use then? Any links please?


I feel a large amount of credit card flexing coming... <:(


Rich
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andyn

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Re: Need for(a bit of) speed...
« Reply #22 on: September 27, 2009, 04:22:22 PM »

Get yourself back on the Electra website and see if anyone has kit for sale. You need a 1/8" or 3/16" flexi driveshaft set, strut and a helm rudder.
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das boot

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Re: Need for(a bit of) speed...
« Reply #23 on: September 27, 2009, 04:27:45 PM »

Thanks Andy...I'm gonna regret this, I know I am.   :o


Rich
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das boot

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Re: Need for(a bit of) speed...
« Reply #24 on: September 27, 2009, 07:07:43 PM »

Why will a direct drive submerged shaft be terrible...anyone tell me? My old MRH Isotope/Bullet combo used to go like wotname off a shovel, and that had a submerged drive, come to think of it so did my MRH Silak.


Rich
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