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Author Topic: Perkasa 49in Renovation.  (Read 25321 times)

gregk9

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Re: Perkasa 49in Renovation.
« Reply #75 on: August 08, 2011, 05:41:17 PM »

I have finally managed to 2test" the boat out, fitted witgh twin 700 bb turbo motors and to be honest, was not impressed by its lack of performance.
So I am having to go back to the drawing board and rethink what size motors to fit, 700's on 12v is insufficient to move the boat at anything other than a moderate "cruise".
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Steve. G.
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treeboa

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Re: Perkasa 49in Renovation.
« Reply #76 on: August 08, 2011, 06:00:14 PM »

hvaing just recently recovered from the attic my perkasa`s ones triple shafts and i have a pair of re750 motors from when i was building it, never purchased the third one for some reason !!, be interesting to see how you get on with this boat and your final motors/setup
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Andy_k

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Re: Perkasa 49in Renovation.
« Reply #77 on: September 03, 2011, 12:59:50 PM »

I have got to say I have been reading this thread with great interest, lets be honest here and say that there is something about the Perkasa that people are drawn to and I have to label myself here among the many ,I run a 49" wooden hulled one and have another 2 unmade kits in the attic one fiberglass and another wood one  but they are not very good kits are they ?   the fiberglass hull is bad by any means with the sides flaring out giant rockers on the underside this in its self will cause performance problems and thats before we get to the choice of motors and battery combinations and peoples opinions on how there boats perform how many times have you seen one of these boats on the local lake with the bow out of the water and people saying you've got that going well or doesn't that look good on the plane when truth be now that just because the bow is up it is not on the plane in fact it is pre-plane pushing water and when planning the is sitting on top of the water and to get to this point you need enough power once there you can ease back a little on the sticks and save battery power in a model is difficult to do especially on a budget but can be done.
First off look at the hull it is a hard chine hull for it to work correctly you need sharp edges on the chine line so that the water will break cleanly off it to give you lift you will require, next at the stern at approx where the prop tube exits down to the rudders the is a big dip this called a rocker and will suck the boat down on the water again not what you want but time and filler or a thin ply false bottom should sort it (and before anybody interjects and says well I got fiberglass hull and mine goes really well, well stop and think how much better it COULD GO? )
Apologies to you Greg but I have only just read this thread after you have finished the hull  and may not want to carry out this mod but just my opinion your choice of motors 9.6v would have been the ones to go for as they rev higher but for now we will work with the 12v ones first off the props are too big with the amount of weight you are carrying in the boat its not allowing the motors to rev in mine I am running propshop 3 bladed scale props I think 37mm I would give you the number but at this point I don't have it to hand but can be got, right batteries are going to be a problem but with a little time can also be sorted cheeply with a bit of time on your part what I did is go through ebay on the model car section you can get some high power nimh packs there that have been used I think most of the car people are moving over or moved over to lipos and are selling off there old packs these have been used but for our purpose they are dam good at a knock down price to boot you can pick up 6v mardave packs 4 of those would suit you but it would be better to up the voltage to better the performance on those motors
this is just my own opinion based on my own experiences with this model and for the record in my Perkasa I run 2 700 turbos running 14.4v through 2 robbe navy 535 esc to get the power I have 8 x7.2 volt 3300 second hand packs sourced from ebay for around 25 now with this little lot I get about 45 mins running time hard to believe but true
Andy

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Right which one will I do next?;)

gregk9

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Re: Perkasa 49in Renovation.
« Reply #78 on: September 04, 2011, 01:17:28 PM »

Thanks for your reply and details about your own builds/conversions. I have since ripped out the twin 700 turbo motors and sold them on to someone else, so the hull is awaiting a further engine transplant.
but that is as far as it has gone for now and may remain in this state for a while yet.
I have the " RMAS Moorhen" to complete first before i continue with anything else as this is taking up workbench space, so needs to get finished to make space available for further," experimentation" with the perkasa.
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Best wishes.

Steve. G.
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http://chasewatermbc.blogspot.com/

gregk9

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Re: Perkasa 49in Renovation.
« Reply #79 on: May 28, 2013, 06:20:54 PM »

Ok, SO after resigning this boat in the attic for a while, and managing to complete one build out of the way, its now to "rethink" the powerplant on this hull.
YES, brushless are now in the running and will be looking for a "twin motor" setup, if any of you have suggestions for suitable motors. A couple of people have already suggested going for outrunners rather than in runners and simply using a water cooled motor mount.
 
I have 7.4, 11.1and 14.8v lipo batteries available, as  I now run these batteries in 90% of my boats, all rated between 25 and 30c.
 
So what size/rating motors does anyone recommend and also prop size/type.   the hull already has twin M4  solid shafts in situ.
 
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Best wishes.

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

Gazza

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Re: Perkasa 49in Renovation.
« Reply #80 on: May 29, 2013, 12:56:05 AM »

Wow guys love this thread and the info . .  Me thinks my scratch built Glass fibre hull will deffo have the 6.5cc nitro in then
 

 
And this baby to make it go LOL
.

 
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bubbletop409

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Re: Perkasa 49in Renovation.
« Reply #81 on: September 26, 2013, 05:37:06 AM »

I have a 1/16th scale (60") scratch built Higgins PT powered by two Astro 40's, turning counter rotating 40mm props. Batteries are four 11.1 V li-po's wired in series/parallel, supplying voltage to a Dimension Engineering ESC. Total weight of the boat ready to run is 23 lbs. My boat is capable of far more than scale speed and run time at moderate ( scale ) speed is 45 minutes plus.
Astro Flight has seen fit to raise their prices to a ridiculous level so I am now looking for a power train package that will offer similar power and speed in a boat of similar size and weight.
Please offer all suggestions, thanks, Larry.
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