Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Navy - Military - Battleships: => Topic started by: gregk9 on November 23, 2010, 07:07:35 pm

Title: Perkasa 49in Renovation.
Post by: gregk9 on November 23, 2010, 07:07:35 pm
Following on from yminitial request for some helpful hints in the beginners section, I am beginning the renovation of a 49 inch Perkasa torpedo boat. the original Kit as a Precedent one, fitted with an "i/c" engine at some stage, which has been removed and the following owner had tried to convert the single prop to electric drive, but not having sufficient speed on the water, the craft has been sold on and now I own the craft and am about to start a refit to include twin elkectric drive motors with independent propeller shafts, but will include the original centre rudder board, thuis giving 3 rudders and 2 props.
I will be fitting [following Perkasaman's suggestions] twin graupner speed 700BB turbo motors and runnign 12v batteries in a twin battery pack setup for added capacity on the water.
I am proposing to add a working radar, replace the original torpedo carriers from the over thick dimensioned wooden items supplied in the kit. Add operational navigation lights, improve the open wheelhouse detailling and seats, improve [or replace] the original front mounted bofors gun and to add a rotational servo to the mount. Same goes for ths missing stern gun mount, this will be constructed and made to rotate also. All the original railings have been removed for replacement later.
This i think is enough info for now, but any help with detailling pictures or pictures of your own craft would be greatly appreciated as this refit progresses. :D
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on November 23, 2010, 08:59:10 pm
Pictures of the "before" craft.
I firstly lifted odd the superstructure and then took to the "washing dep't", namely the bath! Sprayed the main deck and the superstructure with ordinary car "traffic film remover" which rapidly dissolves the grime and old grime from the i/c engine deposits, then washed off with warm water. I prefer to use this type of film remover as its biodegradable in water, its cheap to buy, does not harm any paintwork or glue and leaves the surface clean and clear of any residue as it even removes polish and silicones .
(http://s3.postimage.org/14wqrqe2s/101_3342.jpg) (http://postimage.org/image/14wqrqe2s/)

(http://s3.postimage.org/14wsf9qkk/101_3344.jpg) (http://postimage.org/image/14wsf9qkk/)

(http://s3.postimage.org/14wu2t32c/101_3352.jpg) (http://postimage.org/image/14wu2t32c/)
Title: Re: Perkasa 49in Renovation.
Post by: Perkasaman2 on November 23, 2010, 09:35:09 pm
Hi greg, I found this site and it contains some good info sources and pics.

http://sites.google.com/site/kdperkasa/Home
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on November 23, 2010, 10:37:13 pm
Thanks for the link, it is appreciated.
I have now removed all the main deck fittings, hatches,bollards, rail posts,vent heads etc, so I can resand the deck properly and get a smoother finish and loose all the open wooden grain that is still visible through the paint.
I have removed the original centre propeller shaft, with careful and prolonged use of my dremel with a small router bit, I carefully cut away the fibreglass matting and filler that bonded it to the hull floor, both inside and on the outside, to allow me to remove the shaft completely. At the same time I also removed the stern water pickup pipe, thats was installed forward of the centre rudder bar. being as Im going to use motors with cooling fans already fitted inside the motors, i dont really ned a water pickup, so have removed it to reduce drag in the water.
I have filled the resultant hole in the hull by these 2 items with some P40 glass filler. One reasonably dry [but not too dry] I gacve it a good sanding with a flat block to remove the excess filler before it sets rock solid, as its easier to sand like this. then ionce it was 100% set, I finished off the sanding with some finer 800 grit paper before adding some fine moddeling filler to fill the smaller gaps that remain. I will leave this overnight to dry fully before flatting off using the 800 grit paper "wet" to get a finer smoother finish.
(http://s1.postimage.org/1964ugh1g/101_3360.jpg) (http://postimage.org/image/1964ugh1g/)

(http://s1.postimage.org/19685j610/101_3356.jpg) (http://postimage.org/image/19685j610/)

(http://s1.postimage.org/196bglv0k/101_3361.jpg) (http://postimage.org/image/196bglv0k/)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on November 24, 2010, 05:16:20 pm
After careful consideration, I have removed ALL the main fittings from the upper deck, cabinets,lockers,gun platforms as in my opinion they just dont look right at all. the original builder had made these items from wood, but had not bothered to sand the sawn edges, sand the wood before painting etc, so they look appauling. So I will use the items as patterns and will make new ones from plasticard.
I have now given the main deck its first coat of sanding primer, to again, fill all the wood grain, this will be sanded before a second coat applied.
I have cleaned up the wheelhouse window frames, prior to sorting out some windows to fit, but they wont go in untill the whole thing is repainted.
The centre propeller shaft hole is now fully filled and sanded smooth, but will leave the hull "as is" untill I have fitted the 2 new shafts and bonded in place, then I can fully finish off the hull before painting it all again.

Incidentally, has anyone else fitted a "transom flap" as  it appears they did have one fitted, albeit usually set at 0 degrees but adjusts to  3 degrees "down angle".  id be interesyted to hear if anyone has and how the boat performs with it fitted.

I do run a similar item on the stern of my dusseldorf firebaot [as they had them fitted too] and that works well and stops the stern sinking too deeply under higher speeds.
(http://s3.postimage.org/1awxmtm10/101_3362.jpg) (http://postimage.org/image/1awxmtm10/)

(http://s3.postimage.org/1awzacyis/101_3363.jpg) (http://postimage.org/image/1awzacyis/)
Title: Re: Perkasa 49in Renovation.
Post by: TomP on November 25, 2010, 12:10:47 am
Hi, I also have a 49" Perkasa. I have the rear transom flap fitted and I am currently installing a Pneumatic system to raise and lower it. It seems to stop the props dragging air down the back of the boat and also helps bring the front of the boat up on the plane. I have 3 Props and 2 rudders, just a word of advice as I have been there and failed, keep the boat as light as you can. I used 3x Graupner 600BB turbo motors on 7.2 Nimh battery packs and they struggled to get any speed. I have since installed 3x 850 MFA torpedo motors on 12V Nimh finally I get the scale speed but because of the high current draw (about 20Amps) my Mtroniks 40A speed controllers cut out as the voltage drops to low. Its been an never ending battle caused by myself as the boat is too heavy. Ive been told the best solution for the 49" hull is a single prop and rudder, 850 MFA motor 12V Nimh battery and a 30mm prop but its your boat do what you want and think is best, Ive had to many people giving me their expert advice which never helps. Good luck Tom 
(http://s3.postimage.org/1dd89qn5w/DSCN0646.jpg) (http://postimage.org/image/1dd89qn5w/)
Title: Re: Perkasa 49in Renovation.
Post by: Perkasaman2 on November 25, 2010, 10:19:35 am
Hi tomp, The Graupner Speed 600BB Turbos would need to be run on the higher voltage of their operating range (4.8 - 14.4v) to show their potential and I can understand their poor performance on 7.2v.
The MFA 850 motor at 600g is a much heavier motor than the 220g Speed 600BB Turbo unit and have increased hull weight by 1140g, however, they have had the advantage of higher 12v running and planing was achieved. (It would be very helpful to know what size props were used with both the earlier Speed and current MFA setups.)
My twin 700BB Turbos ( 350g each) spin a pair of 45X props and use twin sla's (2.6 kgs each) running @ 12v 14amp/hr in my 49 grp Perkasa and planing performance is excellent, although the hull is heavily burdened. My 700 Turbos  have a voltage range 4.8 - 16.8  and are probably running at their most efficient (75%). although more oomph is there........... on paper. I will probably run/trial twin or quad nimh packs and should save at least 3kgs of battery weight. I will dust off the hull /do comparative trials when the weather is warmer.
I also bought the fittings packs, however I have'nt used them, largely because of their heavy weight, however, they are a huge improvement on the kit items.  
  
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on November 25, 2010, 12:33:11 pm
we have similar problems of weight with the 102 ft vosper patrol craft , it started with a pair of 900 brushed motors , but after the escs melted on the bench have gone for a twin brushless set up ( e flight park 450 s ) through individual esc s but running from a single 12volt 7 amp gel battery , it now gets up to plane but with a better battery ( ie less weight ) should help its performance ? photos under vosper ferocity , weve since learned its not the ferocity but i cant change the title ! :-))
(http://s3.postimage.org/1hhw0tp6s/212.jpg) (http://postimage.org/image/1hhw0tp6s/)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on November 25, 2010, 01:58:02 pm
I have already removed the centre prop shaft and sealed the hole up, so I will fit just the 2 motors as Perkasaman suggested.
I am wary of the weight of the boat, thats why i have removed all the original wooden fittings, lockers , guns etc and replacing with far lighter plasticard items, plus can get a much cleaner/sharper edges on all the lockers with plasticard over the old wooden ones.
For example, Ive just weighed the forward 40mm bofors wooden version thats was fitted to my boat, it weighs in at 5 ounces, whereas the new one im making in plastic is a mere 1.5 ounces at present, and thats half built as yet.
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on November 25, 2010, 03:58:55 pm
are you able to remove sections from bulkheads to save any more weight ? thats what ive done to the patrol boat , some have been drilled , while others have had large sections cut out using my dremel & a disc cutter ( bulkheads are 1/2 inches thick , & the keel is over an inch thick ! )
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on November 25, 2010, 05:04:12 pm
Good idea ! id not thought that far yet, but yes, its worth looking at, once ive arranged where the twin motors are going to sit. there are already 2 wooden cradles set on the hull floor, either side of where the petrol engine sat, but they have never had anything in them. There is a square plinth in the stern section, nearest the rudder post which I presume was where the fuel tank sat. It has been fibreglassed in, but will coax that out too with the ever faithful dremmel [ha ha].

However, i do want to add another bulkhead in, towards the bows, as where the 40mm bofors sits, the deck is very flexible, so when I cut out the circular disc to enable me to make the gun rotate via a servo, I will add a plstic constructed bulkhead in, to hold the deck level and stop from drooping.
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on November 25, 2010, 09:41:14 pm
when i refitted the boat , it too was a conversion from single shaft to a twin shaft , i removed the original 17" shaft  but fitted a pair of 12" m4 ones , i also placed them further back in the hull , the new motors are now below the funnels , behind them ive a full height watertight bulkhead that has our heavy 12v 7 amp gel battery , the rear compartment just houses the steering gear and rudder servo ! it may next summer get treated to a pair of lighter higher voltage battery packs in the quest for more speed !
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on November 27, 2010, 11:56:57 pm
I have started to lighten some of the interior bulkheads, starting with the easiest one to get at, the stern bulkhead. I have left sufficient strength to hold everything together, by virtue of the 2 vertical pillars and left a horizontal bean top and bottom. I still have to sand smooth all the cut edges, so it looks a bit on the rough side as yet. the next one to attack will be the forward one, but I also need to cut a lareg doameter hole in the forward deck yet, so i can drop in the 40mm bofors with a servo mounted underneath, so that will give me better access to the bulkhead for lightening too at the same time.
I have also removed the stern exhaust covers, the original wooden ones look too large in diameter, so will make up some new plastic ones and maybe even deepen the actual ports so they look like they are actually turbine exhausts. Whilst the covers were off, I took time to run my sander across the stern to level the fibreglass off to look and feel more squarer then the original mould had left it.
(http://s1.postimage.org/25509usec/101_3366.jpg) (http://postimage.org/image/25509usec/)

(http://s1.postimage.org/2553kxhdw/101_3368.jpg) (http://postimage.org/image/2553kxhdw/)
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on November 28, 2010, 05:55:00 pm
when i put the rotating & elevating gun on the one i made i fitted a sub plate below the deck with the rotating servo fitted to it , then using a long m3 bolt and tube transmitted the drive out through the deck to the gun , my method for elevation was a micro servo inside the gun body ! hence ive only got a very small hole that splashes of water could find there way into the hull ! ! most models seem far to over engineered when you look at the thickness of some of the bulkheads , id rather have a lightweight model than something that becomes too heavy to carry to the lake .
Title: Re: Perkasa 49in Renovation.
Post by: TomP on November 29, 2010, 10:32:48 pm
Hi, yeah i wish i had tried the 12V batteries the only problem was the motors were reving so much that they were cavatating so the motors would rev but the boat wouldnt go forward thats why i decided to change them to a lower rpm but higher torque motor. I had 6 7.2V nimh battery packs on the BB turbos but reduced that to 3 12v battery packs to make the weight the same with the larger MFA motors. the props are 40mm just need to stop the speed controllers from cutting out maybe a capacitor would help?? Tom 
Hi tomp, The Graupner Speed 600BB Turbos would need to be run on the higher voltage of their operating range (4.8 - 14.4v) to show their potential and I can understand their poor performance on 7.2v.
The MFA 850 motor at 600g is a much heavier motor than the 220g Speed 600BB Turbo unit and have increased hull weight by 1140g, however, they have had the advantage of higher 12v running and planing was achieved. (It would be very helpful to know what size props were used with both the earlier Speed and current MFA setups.)
My twin 700BB Turbos ( 350g each) spin a pair of 45X props and use twin sla's (2.6 kgs each) running @ 12v 14amp/hr in my 49 grp Perkasa and planing performance is excellent, although the hull is heavily burdened. My 700 Turbos  have a voltage range 4.8 - 16.8  and are probably running at their most efficient (75%). although more oomph is there........... on paper. I will probably run/trial twin or quad nimh packs and should save at least 3kgs of battery weight. I will dust off the hull /do comparative trials when the weather is warmer.
I also bought the fittings packs, however I have'nt used them, largely because of their heavy weight, however, they are a huge improvement on the kit items.  
  
(http://s1.postimage.org/2kt1u9vlw/DSCN1420.jpg) (http://postimage.org/image/2kt1u9vlw/)

(http://s1.postimage.org/2kt55cklg/DSCN1414.jpg) (http://postimage.org/image/2kt55cklg/)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 01, 2010, 09:29:56 pm
Ive now had the x45 props arrive as well as the new rudders. So Ive marked out the rudder positions and installed them, so i can fibre bond in the support blocks, as well as make up the link rods between all 3 .
ive also started work on the transom flap, this [so far]is 2 layers of 0.4mm plasticard, the third layer to be added once these 2 are dry. I can then add the hinges and linkage rods. the rods ive decided will be adjustable ones, so I can have a play with different angle settings, to get the best performance from this particular boat [hopefully]. admittidly there's only about 5 degrees to play with so its between -1 and plus 4 in my books. but we will see in time.
(http://s3.postimage.org/345y9mcw4/100_3386.jpg) (http://postimage.org/image/345y9mcw4/)

(http://s3.postimage.org/345zx5pdw/100_3387.jpg) (http://postimage.org/image/345zx5pdw/)

(http://s3.postimage.org/3466jb3d0/100_3388.jpg) (http://postimage.org/image/3466jb3d0/)
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on December 01, 2010, 09:48:40 pm
your rudders look quite big , you may also need to cut the top and bottom corners off to assist in reducing the lift when the rudders are used at speed ! the twins i fitted in the patrol boat have an adjustable tie rod that links the pair together at the outer end of the tiller arms while my servo is acting on one of the inner most holes , i have however found a dual  ended ball link that may be of use to you for your rudder , its a ripmax part number F-GPMQ3930  retails at £ 2 .75 , this may make the linkage neater ?
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 01, 2010, 10:36:52 pm
Ive matched the 2 rudders ive fiotted, with the original that was already in the hull, this being a "medium" size [according to the books], its approx 54mm deep by  34mm at its highest width point.
 but as it was going to be matched up with 45mm props, they may well be ok, but proof will only be once its in the water, as at higher speeds, I tend not to put a full rudder input in anyway with my boats, knowing how it can affect them and cause  them to lift or baulk out in the water.
thanks for noticing though, it is appreciated.

So what dimensions are your rudders then?

I have a selection of screw threaded ball/rose joints I make all my linkage shafts up with.  I cut 2mm rod to suitable lengths, and then cut sufficient screw thread on them, thus giving a nice fine adjustment to the links. these being of the "aero type", not car ones as they pop off too easily, the ones I use have a nut and bolt going right through the centre of the ball joint to secure to the servo arm, thus going "belt n braces", to prevent linkage loss due to vibration so to speak.
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on December 01, 2010, 11:44:50 pm
i cant remember off the top of my head how big the rudders were , & the boat now lives in woking , which is around 50 miles from here , so cant check very quickly ! i know the idea of belt n braces with the rudder linkages as its no good racing across the lake if the rudder wont turn it around at the end ! im currently fitting the pushrod connectors to all of my builds , as iits a solid metal unit held onto the sevo horn with a nyloc nut , the linkage bar is retained with a grub screw , im also using balraced servos for the rudder control .  :-))
Title: Re: Perkasa 49in Renovation.
Post by: Perkasaman2 on December 02, 2010, 10:45:54 am
Lots of progress.
It may be worth fitting small brass washers to the rudder stems where they enter the hull to allow the rudders to swivel more freely. The E boats utilised what became known as the 'Lurssen Effect'. It was discovered by their designer. The outside rudders were offset outwards a few degrees and this slightly increased speed/reduced drag. I don't think this phenomena was ever properly understood, however this effect and advantage was exploited. (The allies discovered this subtle arrangement when an E boat was captured intact and evaluated. Apologies for rambling a bit.  :-) )
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 02, 2010, 11:27:11 am
Thanks Perkasaman, will take the brass washer bit on board, I have some,somewhere, will track them down and slip them on. Same goes for the small plastic/nylon hinges I have. I've got a pack of them somewhere, but do you think you can find them when you want them? [ha ha]. I was going to use them in the "plastic sandwich" of the transom flap, thats why I havent added the "third layer" together yet, wanted to leave apart till i'd got them in, so they wont show too much once assembled together.
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on December 03, 2010, 09:06:38 pm
sandwiching the plastic hinges sound different , im also looking into making my trim tabs work , so may try this too , i was also thinking of making my tabs from stainless steel sheet , as i normally operate in salt water ! its how to make the hinges that has me puzzled ! !
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 03, 2010, 11:40:04 pm
The hinges I use came from an item I needed for the rear stern hinged door on my graupner Adolph Bermphol Lifeboat. I needed some hinges, that were  lightweigth, but alos not going to rust away when submersed in water, so came across thes little cute things, belonging to the aero moddellers brigade. They use them for the wing and tail flaps, light in weight, 2 sections of the hinge are a quite flexi plastic, with a stainless steel pin locking the two halves together, so no chance of premature rusting [ i didnt say any rusting- as appreciate you will get a slight corosion on this st/steel pin].

they are pre drilled with all the holes you see in the pic, so adapt easily to any fitment, plus you can source larger hinges if these are too small for your purpose.  price? cheap as chips mate, bought a pack of 10 for less than £3.00 inc postage.
Thats why i said ive just simply cut a slot in the 3 layers of plastic ive bonded together, these hinges will slip in to the slot, then its either glue them in or drill through and drop some plastic rod through and heat over the ends, like a rivet, so can be removed/replaced if ness later, by simply cutting the heads off the plastic rivets and the hinge slides back out again. then to attach to the stern, you could use some stainless steel bolts and nuts, rather than just risk to epoxy glue.
Title: Re: Perkasa 49in Renovation.
Post by: Perkasaman2 on December 04, 2010, 12:11:07 pm
The trim plate in use only needs a few degrees of adjustment to generates a slight 'upforce ' to dissuade the stern from digging in at speed and some sort of micro adjustment  rather than twin servo powered rams may be less complex and  more useful. Independant adjustment of (wider-spaced) supports will enable fine tuning/warping and this may also reduce 'crab running'.
This facility may help to correct any lack of symmetry in the submerged hull shape or any steering/handling bias where handed props are not being fitted and  help reduce/neutralise the torque reaction of the hull and encourage straight running at speed. This upforce from the trim shelf should also help to reduce the size of the stern wave and 'rooster tail'. Less water displaced is more efficient.
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 04, 2010, 02:44:20 pm
I have an old pair of robbe trim tabs, somplete with some threaded adjustable rods attached, was going to raid them off the robbe ones, and adapt to fit the perkasa transom flap. All i'll need to do is replace one of the threaded rods with longer versions, but have loads of 2mm rod and a 2mm die set, so can make these up easily.

Pics attached of the "donating" items, no, not using the bases, just the threaded rods and joints.

(http://s2.postimage.org/2fd8zqisk/100_3398.jpg) (http://postimage.org/image/2fd8zqisk/)

(http://s2.postimage.org/2fdan9vac/100_3399.jpg) (http://postimage.org/image/2fdan9vac/)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 06, 2010, 05:42:58 pm
I have started to cut out the drop chutes for the turbine exhaust covers to sit in. Well, i cant see the reason why I cant actually sit these covers in their "open position", otherwise, seeing the boat skipping across the water with them all close looks so silly in my opinion. So I will create three exhaust covers which will sit down in their respective cutouts, then drill the stern and insert 3 turbine exhaust pipes keeping them short, with sealed internal ends to prevent water ingress of course, but at least it will look a lot better. I was considering putting all 3 covers on a servo link, so could open/close via landing gear switch on transmitter [thinks long on this one]. but then think of added weight of yet another servo. maybe ok if it get to correct planing speed with my setup, then try this out later.
(http://s2.postimage.org/2wh90z4is/100_3402.jpg) (http://postimage.org/image/2wh90z4is/)

(http://s2.postimage.org/2whcc1tic/100_3403.jpg) (http://postimage.org/image/2whcc1tic/)
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on December 06, 2010, 09:14:36 pm
you could always use a mini or micro servo its not as if there will be any weight to pull up / down ! why not be different !
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 07, 2010, 07:40:30 pm
I have now cut a hole in the forward deck, to enable me to do a few jobs:
1/ add additional deck support, as forward deck is flexing,
2/ cut out sections of forward bulkhead, to lighten /weigth save.
3/ allow access to fit gun mount servo, to rotate the 40mm bofors gun monting.

I have also given the rear stern support its first filling, to remove some of the roughness fro  the initial cutting out for the exhaust doors.
Title: Re: Perkasa 49in Renovation.
Post by: Perkasaman2 on December 07, 2010, 09:21:41 pm
You' re really getting stuck in to the hull. The redundant i.c engine mounting tray looks well fixed but it's centre-line position is likely to obstruct your proposed twin turbo layout.......... removing it should save quite a bit of weight.
(I used three matching plastic lids from small camera film containers to simulate the gas turbine exhausts on the transom)  :-)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 07, 2010, 09:28:45 pm
Thanks for your observation perkasaman, I was "wondering" about that centre mounting, but same time, was wondering if I could still use it for the centre battery mount. but being as it is a sloping panel, its best to remove and replace later with a thinner item.

Will remove carefully, as its a bit close to the hull floor ! plus dont know how good the original chaps glassing was to the underside of this panel to the hull floor either, but here goes !

i'll do this before i start cascamiting the deck beams back to their bulkheads, leave things in a flexi state for now, give me more room to get my oversize paws inside [ha ha].
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 07, 2010, 09:49:21 pm
Easier and quicker than I thought. I simply drilled a line of holes across the rearward edge, across the baseplate, then joined the dots untill it was fully cut, then gently levered it up and down to break the glue edge at the foremost end and lifted out in one piece !
Still leaves me with an angled keel [piece if I do need to fit a bettery tray along it later.
(http://s4.postimage.org/35r22ux44/100_3414.jpg) (http://postimage.org/image/35r22ux44/)

(http://s4.postimage.org/35r3qe9lw/100_3417.jpg) (http://postimage.org/image/35r3qe9lw/)

(http://s4.postimage.org/35r5dxm3o/100_3415.jpg) (http://postimage.org/image/35r5dxm3o/)

(http://s4.postimage.org/35r71gylg/100_3407.jpg) (http://postimage.org/image/35r71gylg/)

(http://s4.postimage.org/35racjnl0/100_3413.jpg) (http://postimage.org/image/35racjnl0/)

Thanks for the tip on the exhaust covers, i was thinking of what to use and actually did think of a possibility of using a film tub cover, will dig some out, do have some somewhere!
ive had to post the previous post update pics here, as seemed to of lost them somehow off the post.
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on December 07, 2010, 10:22:48 pm
lightening seems to be going well , its suprising how much extra weight some folks add into what should be a fairly fast model ! keep up the good work . jon
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 07, 2010, 10:36:55 pm
I suppose it really stems from the "first build". If the person putting the hull together from the box, looks at the manufacturer supplied bits and simply glues them in place, then they are simply following the instructions, "by the book". there are many of us however who "look" at things and think, "does it really need to be this thick/thin?  perhaps we ought to double this items thickness for longetivity perhaps, or on the other hand, we look at some internal bracing pieces and think they would be better off holding up a motorway bridge somewhere!
Yes, it would be great to find a boat where someone has given a lot of though to its original build, but then, we wouldn't have anything to renovate or modify, now would we? [ha ha]. As all models would be as everyone would want them and be totally boring for us

I've now mixed up some cascamite and rebonded in the  internal bulkheads, where they have sprung away from the wooden deck, this will set nicely overnight, along with the forward brace i have installed to support the forward deck, forward of the bofors mount.

Time me thinks for a cuppa !
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 08, 2010, 05:24:30 pm
Following on from my sucess in removing the old engine tray, I had a go at removing the original fuel tank from the stern compartment. Witha few well aimed strikes from a wide bladed chisel, yep, the wooden plinth has reached the bin too!  I was amazed how little was actually holding this in place and is now leading me to be more than concerned with the strength of the remaining fibreglassing, put in by the original owner. It seems all the resin is in the very outer layer and nothing has soaked through to the lower matting, or to the actual hull glass mat itself !

makes you think don't it ?

I have also drilled the turbine exhausts out, in fact i will not only use the plastic film container lids for the exhaust covers, but use the little plastic tubes for the exhaust pipes too. Well why not, they are open one end and totally sealed the other, saving me a job of making some plastic tubes and end caps. One the insides are painted black/charcoal grey, they should look reasonably acceptable.
(http://s3.postimage.org/1lu30n3t0/100_3420.jpg) (http://postimage.org/image/1lu30n3t0/)

(http://s3.postimage.org/1lu4o6gas/100_3418.jpg) (http://postimage.org/image/1lu4o6gas/)

(http://s3.postimage.org/1lu7z95ac/100_3419.jpg) (http://postimage.org/image/1lu7z95ac/)
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on December 08, 2010, 05:41:40 pm
its a pity those film cans wernt black ones ! they are looking rather close to the tiller arms , or do the arms sit 90 deg around when they are connected ?
Title: Re: Perkasa 49in Renovation.
Post by: Perkasaman2 on December 08, 2010, 05:46:05 pm
Good idea! I had'nt thought of using the cannisters.......... DOH!!!!!  :}
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 08, 2010, 05:52:58 pm
There is at least 15mm clearance over the tops of the rudder post levers, plus none of the rudder link arms are secured as yet. I want to "dry fit" everything in the stern first before securing anything in place. that way, i am fully sure everything will operate and not foul any link.

yes, i did loom for some black tubs, but like everything else, you've thrown them away ages ago !
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on December 08, 2010, 09:13:35 pm
isnt htat the story of most things , havnt thought of a use in ages , then the day or so after youve binned it you can think of a use for it ! good to check everything fits and works before closing section off ,
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 08, 2010, 09:47:02 pm
My , er, "intentions" are to finish off the exhaust holes, make sure the film tubs are a good fit, then sort the rudder linkages out, make a mount for the rudder servo and get that set in place, then complete the rudder links, then finally, setting the exhausts back in final place. I can then say that the stern section [internally] is done and dusted. yes, Still have the lower transom flap to put on, but thats external.

but still thinking of the small micro servo for the exhaust doors too.....................

but plenty of room for that to happen, even with all the rudder  links in place, as all the doors can connect/link to one long brass rod, then it only needs a single lever slot through the transom to operate it...............

lets just say, that bit's still in the technical design dep't !
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on December 08, 2010, 10:45:43 pm
boredom has had me looking on the british military powerboat trust web site this evening , look under brave class and follow the pages down , as there are some interesting drawings & diagrams showing the linkages used on the full sized vessels , it may be of some interest to how to set up your model ? the diagrams i was looking at show both the transom flap and the exhaust covers which appear to be linked ? they also have some good black and white photographs showing various boats . jon
Title: Re: Perkasa 49in Renovation.
Post by: Perkasaman2 on December 08, 2010, 11:17:56 pm
The kits are sold with a very good booklet full of info + pix and it's well worth getting a hold of for detail......... unfortunately I've misplaced mine and coupled with the fact that my scanner is now jamming, does'nt help matters if I locate it.  %) Perhaps another Mayhemmer has a copy available. The kits are currently sold, supplied and copyright of 'Anglia Model Centre' and they may help:

  http://www.angliamodelcentre.com/index.php?manufacturers_id=13

(There has been some criticism of the quality of these kits in the past, but they do still represent very good value for money, especially the 1:24 scale, which does make into a very large and impressive model on the pond.

I don't know if you've chosen motor mounts, but Mark of MMB sells a hybrid which can mount 700/800 motors and will give excellent clearance if cooling coils are needed later.His range of couplings are also quiet and 'length adjustable'. He also retails an inexpensive motor/gearbox for radar. His site is well worth a look:

http://marksmodelbits.ieasysite.com/index.html

 
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 14, 2010, 03:17:12 pm
Thanks perkasaman, Your comments are noted. I have already ordered my prop shafts via Mark @ MMB, as his versions seemed a good buy. I have not yet ordered motor mounts, as yet, no finances to buy the motors ! Will see what lands in my lap on the 25th of the month first before going for broke.
im just starting to link uip the ruddeers at present, making my own threaded/adjustable link rods, prior to then fixing the  lower transom flap hinges in place, adding thr link rod for the exhaust flaps, then bonding in the exhaust tubes.

Want to start at the bottom point of the stern first, then work my way upwards to deck level, so I dont leave myself in a position where Ive fixed something in, but need to get "below" its level for something else.  It could well still happen, but thats my intentions for now.
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on December 17, 2010, 05:23:30 pm
I have finally recieved copy of the original perkasa build booklet, provided by precedent. it has some wonderful images to help my renovation and revamp to give the boat more details.
(http://s4.postimage.org/28e8yvskk/PC150185.jpg) (http://postimage.org/image/28e8yvskk/)

(http://s4.postimage.org/28ec9yhk4/PC150187.jpg) (http://postimage.org/image/28ec9yhk4/)

(http://s4.postimage.org/28efl16jo/PC150186.jpg) (http://postimage.org/image/28efl16jo/)

(http://s4.postimage.org/28ekjn810/PC150195.jpg) (http://postimage.org/image/28ekjn810/)
Title: Re: Perkasa 49in Renovation.
Post by: Perkasaman2 on December 17, 2010, 05:46:18 pm
 :-))
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on January 04, 2011, 10:23:53 pm
managed to do a small bit of conversion to the boat over the Christmas break. I have had a go at correcting the open bridge layout. There appeared to be a door missing leading forward to the forward cabin. So now, instead of a full width instrument panel , I have cut away part of the panel and remade a door and aperture for it.
(http://s3.postimage.org/201aq7ybo/100_3401.jpg) (http://postimage.org/image/201aq7ybo/)

(http://s3.postimage.org/201e1anb8/100_3400.jpg) (http://postimage.org/image/201e1anb8/)

I have also now had the twin stainless steel  propeller shafts arrive from MMB, just awaiting sufficient finances to cover purchase of the 2 700bb turbo motors and mounts to install the power plant.
Title: Re: Perkasa 49in Renovation.
Post by: triumphjon on January 04, 2011, 11:08:04 pm
check out howes models of oxford , they have had the 600 turbos on offer they may have 700s too !
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on January 13, 2011, 11:21:54 pm
Have now recieved delivery of the power plant for my renovation project.
A pair of Graupner 700BB turbo's !
Pair of 13inch length 5mm dia prop shafts

2- 45x props.

Will of course be running twin 12v battery gel pack to give the boat some cruising time in the water.
(http://s3.postimage.org/2okdxu9xg/100_3496.jpg) (http://postimage.org/image/2okdxu9xg/)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on January 18, 2011, 04:12:25 pm
I am now in recipt of a pair of 700BB turbo's and motor mounts, with the kind thanks to Perkasaman [yet again], your offer on these items is greatly appreciated.

I am now about to install the powerplants, but before doing so, I have modified the alloy motor mounts as I noticed that the air cooling slots on the front face of the motors could nto draw air through the motor mount face. So after a little marking out, ive added 4 air slots to enable the internal air fan to draw air fully through the motors when rotating.

I also have drilled a couple of 22mm diameter holes in the motor bases, this is to allow the P40 glass mat and resin, I will  use to bond the mounts down in the hull to fill "in and over" to make sure the mounts are fully bonded to the hull floor, rather than just lay soem resin or epoxy over the top and "hope for the best".
(http://s2.postimage.org/d37o34is/100_3530.jpg) (http://postimage.org/image/d37o34is/)

(http://s2.postimage.org/d3fxruzo/100_3528.jpg) (http://postimage.org/image/d3fxruzo/)

(http://s2.postimage.org/d3j8ujz8/100_3529.jpg) (http://postimage.org/image/d3j8ujz8/)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on January 19, 2011, 11:20:46 pm
I have now installed the motor mountings and propeller shafts. I find its a job that has to be done "all together", to ensure as far as possible, that all is correctly in-line and will run as true as possible. 

So first thing is to put some masking tape on the underside of the hull, mark the centre line, then from the centreline, equally space the propeller shaft "runs" to these lines. I had already got these in place, when I installed the rudders, so I only now had to drill the initial hole to make a start for the propeller tubes.
Don't forget that these holes are not "circular", but a very long "oval" shape, and it takes some careful drilling initially, followed by  a round file, to get the shape almost right.
now you can slide the propshaft tubes through inside the hull  attach the universal joints and then on to the motor drive shafts, making sure the mounting screws for the motors are only "finger tight", so you can remove them easily later. I then placed some balsa blocks between the prop tubes and the hull underside to then line up the motors with the hull internal floor, to make sure the mounts sat flat against it.
once happy, I marked the hull floor to show position of the motor mounts, removed the mounts and shafts, removed the motors from the mounts and them proceeded to bond the mounts to the hull floor with glass fibre paste, this i pushed in to the big holes i predrilled in the mounts to ensure the glass fibre mixed with the layer applied to the hull floor, to help make a full bond.
once this was dry I refitted the motors and reattached the drive couplings and propeller shafts. then with the balsa blocks in place, I initially used some epoxy resin mix to affix the propeller shafts in line to the underside of the hull . Once this was dry, and rechecking the angles of the propeller shafts, i then added a further layer of glass fibre paste to the hull holes made for the shafts to exit, to fill up the gaps around the shaft exits. Last job was to add a propeller shaft support, 20mm from the end of the shafts, behind the propeller, to add a bit of support to the tubes, to reduce the risk of excess vibration when under load.

(http://s3.postimage.org/14q7zsudg/100_3532.jpg) (http://postimage.org/image/14q7zsudg/)

(http://s2.postimage.org/s7866wf8/100_3533.jpg) (http://postimage.org/image/s7866wf8/)

(http://s2.postimage.org/s7bh9les/100_3537.jpg) (http://postimage.org/image/s7bh9les/)

(http://s2.postimage.org/s7i3ezdw/100_3538.jpg) (http://postimage.org/image/s7i3ezdw/)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on January 21, 2011, 05:27:48 pm
Whilst waiting for some rudder arms, as the ones supplied with the rudders are not suitable and dont give me equal swing angle both ways, i have attached the transom flap to the stern. I have used a couple of nylon aircraft aeleron hinges to make the pivots and to attach the hinges securely, i used plastic rivets through the hioles pre drilled in the hinges, simply transferring these through the transom flap itself. It was then justa simple case of using my instant soldering gun to melt the tip of the plastic rivet to mushrom the head to for the fixation. Once all the rivets were complete, i simply spread some exopy resin over the rivet heads on the inside of the stern where the rivet heads came through, to ensure a full watertight seal.
I will make up the transom flap adjustment arms as next item to do, but wanted the epoxy to dry off first before moving anything else.
(http://s2.postimage.org/1a1bkomn8/100_3539.jpg) (http://postimage.org/image/1a1bkomn8/)

(http://s2.postimage.org/1a1evrbms/100_3540.jpg) (http://postimage.org/image/1a1evrbms/)
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on January 25, 2011, 10:35:31 pm
I have now swapped the rudder arms supplied with the brass rudders for straigth arms, as the original ones would not give me equal turn angles. So now after refitting these and also making up some threaded rods to join up the rudders, they are now fully operable, complete with a metal geared servo to cover the loading of 3 rudders on this particular setup.

I have also given the motor setup its first "dunk" in the upstairs  "test tank" and powered the twin 700bb's up for the first time!

Oh Boy !!

Considering the size of the motors, they certanly have some torque, even with a single 12v battery loosly placed in the hull for the test.

I did notice the esc for the motors was getting a little on the hot side, so for now, I've added a small brushless cooling fan motor to the cooling fins to help  keep the temperature below panic level .

The motors? I hear you all ask.................. not a problem, as thery have internal cooling fans as original equipment, plus me drilling air vents in the motor mounts, they didnt even get luke warm, but managed to drain the 12v battery to low volt warning on the esc!

(http://s2.postimage.org/2ekwnj4is/100_3553.jpg) (http://postimage.org/image/2ekwnj4is/)

(http://s2.postimage.org/2ekzyltic/100_3552.jpg) (http://postimage.org/image/2ekzyltic/)
Title: Re: Perkasa 49in Renovation.
Post by: derekwarner on January 25, 2011, 11:39:49 pm
Gregk9....you appear to have a linkage glitch here which will cause different rudder positions on axis relative to the rudder servo movement

STDB rudder linkage arm is connected to the third fulcrum point  :-))
STDB to Centerrudder linkage arm is connected to the third fulcrum point  :-))
PORT rudder linkage arm is connected to the second  fulcrum point  :-))
PORT to Center rudder linkage arm is connected to the first fulcrum point  >>:-( = unequal length = unequal motion to the PORT rudder compared to the STDB & center rudder

A possible solution here would be to use a DUBRO [or similar] Dual swivel ball link between the PORT & STDB rudder connection O0 .....Derek
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on January 26, 2011, 12:59:06 pm
thanks for your very keen observations, but after checking all the links prior to fitting AND considering what components i had in stock, this was the best compromise I came up with.

At worst, I am out by 3 degrees !  [wow  wee wow wow].
 When rudders placed at FULL turn.

Its hardly a problem, not for me, the person actually using the boat. Plus when you have to watch every penny I spend these days.
The use of current "stock" has priority over buying more new kit.

If I have a full time job with money to spare in the bank and money was not an issue, id probably agree with you and go and spend like there was no tomorrow, but when you dont know what bill is dropping through your door tomorrow, I have to be very careful.

Mind you shouldn't we all be thinking like this these days ?
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on January 26, 2011, 07:00:50 pm
The Transom flap is now fitted and I've bonded in the 3 gas turbine exhausts [made from 35mm plastic film tubes]. I have the exhaust doors ready for final painting too, these ive dropped in place for the photo's. Imhave checked the clearance above the rudder arms and rudders, and there is sufficient space to allow for rudder adjustments or replacement if ness.
(http://s2.postimage.org/2mdi62wtg/100_3555.jpg) (http://postimage.org/image/2mdi62wtg/)

(http://s2.postimage.org/2mdjtm9b8/100_3556.jpg) (http://postimage.org/image/2mdjtm9b8/)

(http://s2.postimage.org/2mdos8ask/100_3557.jpg) (http://postimage.org/image/2mdos8ask/)
Title: Re: Perkasa 49in Renovation.
Post by: RaaArtyGunner on January 26, 2011, 08:27:16 pm
Plus when you have to watch every penny I spend these days.
The use of current "stock" has priority over buying more new kit.

If I have a full time job with money to spare in the bank and money was not an issue, id probably agree with you and go and spend like there was no tomorrow, but when you dont know what bill is dropping through your door tomorrow, I have to be very careful.

Mind you shouldn't we all be thinking like this these days ?

Agree
 O0 O0 O0
 :-)) :-)) :-))
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on February 15, 2011, 09:56:13 pm
firstly appologies for updates, but have been busy with the boat club matters, which unfortunately had to take priority over my own minor projects.

Right!
I have started work again on the superstructure and have today been constructing the main forward mast and the base mounting for the radar.
Following from the plans I have, the mast was made up from a piece of plastic tube, so i could feed the upper navigation light through it. the radar mount I made from rectangular plastic rod, purely for strength and rigidity, not wanting to use wood, for weight reasons. I have fitted some plastic tube bushes in the upper radar support and a small tube piece in the lower section, these will act as bearing supports to the thinner brass tube which will link the radar motor [electric] with the radar unit on the top.

I did however insert a small piece of brass tub in to the superstructure first and bond in with expoy resin, to act as the base for the mast, just for a little added support where its needed. the angled pennant support has been glued in place, leaving the upper fittings to make up and fit once the lower items have fully dried.
(http://s2.postimage.org/1vtx5frxg/100_3579.jpg) (http://postimage.org/image/1vtx5frxg/)

(http://s2.postimage.org/1vu0gigx0/100_3580.jpg) (http://postimage.org/image/1vu0gigx0/)

(http://s2.postimage.org/1vu72nuw4/100_3581.jpg) (http://postimage.org/image/1vu72nuw4/)
Title: ESC capacity !
Post by: gregk9 on February 22, 2011, 06:31:29 pm
I actually too the boat to my club pool this afternoon to check out the positions for the drive batteries, to ensure they kept the boat in balance for correct planing angle so to speak.

however on its first voyage, the esc burnt out!.

Now, what ampre rating esc's should I be running with twin 700 BB turbo motors, on 12v batteries?

Can anyone assist here, as I did put in one which i believe was labelled to be a 60 amp esc, but its completey melted it.
(http://s2.postimage.org/httzudes/100_3614.jpg) (http://postimage.org/image/httzudes/)

(http://s2.postimage.org/hu0lzrdw/100_3616.jpg) (http://postimage.org/image/hu0lzrdw/)
Title: Re: Perkasa 49in Renovation.
Post by: Stavros on February 22, 2011, 07:19:25 pm
Well you should have a esc for each motor,Give Dave at ACTion a ring and he will sort you out with Proper esc's and not those silly cheap and nasty chineese ones !!!


Stav
Title: Re: Perkasa 49in Renovation.
Post by: craftysod on February 22, 2011, 08:17:23 pm
I use a Fusion watercooled esc on my big springer,was running on 2 700BB turbo motors,but those motors are power hungry.
Now use 2 600BB turbo motors, get longer run time,and the esc doesnt even get warm.
1 esc and 2 motors,they are many ways to solve the problem
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on February 23, 2011, 12:01:19 am
I am going to refit with twin esc's, i have used the 700 bb's  as they were recommended by several other model boaters who have them fitted to this size perkasa, so was following other people recomendations and due to me limited budget, I'll have to stick with them for a while and just make the most of it.

I have said this before and have to remind certain people again, who dont bother to read earlier posts. My budget is not as big as my enthuisiasm for model boats. I try to make do the best I can. yes, some companies items are far superior but there is no need to rub someone face in it, just because you can afford them and would never dream of going elswhere for parts.
I have used 3 of these types of esc before and had no trouble whatsoever and are still fitted in some of my other boats and working fine.

Advice Is appreciated and I thank those who give this freely.
Title: Re: Perkasa 49in Renovation.
Post by: TomP on February 24, 2011, 11:59:46 am
Hi Gregk9, stick a fuse in line between the battery and the speed controller then if the motors pull to much current it’s just a fuse to replace. I've had the same problem, I should know better being an electrician, and don’t you just love that electrical burning smell!! I had the motor rating at its max current which was 20A so thought a 30A speed controller would be fine, I was wrong and it caught fire, DOH!!  So I put a fuse in line and it was blowing a 40A fuse at full throttle. Learnt my lesson the hard way as usual still I know next time.  Regards Tom
(http://s3.postimage.org/248aw3fyc/Fuse.jpg) (http://postimage.org/image/248aw3fyc/)
Title: Re: Perkasa 49in Renovation.
Post by: Mezza50 on February 27, 2011, 07:36:06 pm
Hi all,

I've been following this thread with interest because a have 49" patrol boat running on 2 x 700bb turbo motors, an electronize FR30HX speed controller and a 12v SLA battery. Based upon the comments of others in this thread should I put a fuse between the motors and ESC or fit another ESC. My question is not meant to send this build thread off on a tangent but the issues encountered by greg are of interest to us all with similar size/type boats.
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on March 03, 2011, 05:47:30 pm
I have had a response back from the suppliers of the faulty speed controller. Apparently it had been "mislabelled" and didnt have the power out rating it was dispatched as.
SO THATS WHY IT FAILED !

NOT BECAUSE IT WAS A CHEAP IMPORT ! as the majority of people making comment naturally "presumed".

The company has been very considerate and have supplied a "pair" of speed controllers for my inconvenience.

I have to say this is more of a response I would of expected,  any Uk or European company would of simply ignored the emails I sent initially. Let alone send a return addressed jiffy bag to return the faulty component.
Title: Re: Perkasa 49in Renovation.
Post by: derfledermause on March 17, 2011, 07:15:23 pm
Good people, may I thank you for this series of very informative posts. I am about to start to build the KD Perkasa kit (all wood) 1/24 scale. Prudance dictates that as this is my first attempt at a vessel of this size, to trawl the model boat web sites for information, hence the thanks for these posts. I have noted the caution that being an all wooden kit, one must be carefull of the weight, if it is to heavy it wont plane properly. I also note that the powering of the vessel must be correct or again, it wont plane properly. The building of the hull and its ancillaries don't bother me that much, but I admit that being a mechanical engineer, electrical and electronic problems fill me with trepidation. I hope that I can follow your example "gregk9" and manage to put the continuing build pictures and text onto this site as you have done.
Again, many thanks to you "gregk9" and "Perkasaman".
derfledermause.
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on March 19, 2011, 12:39:03 am
Many thanks for your comments, dotn worry, this renovation project has not stalled, but I have 3 other projects on the go, this perkasa, a "moorhen" salvage tug [in  this same thread list] and some home based projects on a 1:1 scale!  So I have to spread my time evenly between them all at the present.

Plus, keep my other boats in order, namely my Sun tug, Dusseldorf fireboat and Egrete pusher tug, robbe sea jet,  robbe laser. I do also have a n gauge train layout somewhere in the house [ha ha].
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on April 19, 2011, 11:48:26 pm
I have managed to finally get my boat out on to the water for its first trial tests, to see how it performs and also how it handles with the powertrain and battery setup.
First trial went well, A little trim adjust on the rudders, the 45 X props seem to be doing their job ok. but boat seems slow. So tried a pair of 50 X props, boat running faster now, but heavy drain on the batteries.
So, major rethink, I think 2 battery packs may be too heavy, so possibility to drop to a single gel battery.  Im running twin 12v 7 amp/hr units. I do have a 12v 10amp/hr battery I use in my dusseldorf fireboats, so may slot that in and see how it handles then. Ive not yet fully secured the battery trays in, as I wanted to be 110 % certain first.

I will retry with this battery and drop back to the 45x props for this test, but take the others with me as a substitute if needed for comparison.
Pics attached , but not taken under full power as difficult to operate joysticks and camera at same time!
(http://s2.postimage.org/2h3ggjmp0/P1010108c.jpg) (http://postimage.org/image/2h3ggjmp0/)

(http://s2.postimage.org/2h3i42z6s/P1010109c.jpg) (http://postimage.org/image/2h3i42z6s/)

(http://s2.postimage.org/2h3jrmbok/P1010110c.jpg) (http://postimage.org/image/2h3jrmbok/)
 transom flap works very well, glad i fitted one and also made it with adjustment. I will try  adjusting it next time out as it may need 1 or 2 degrees pos this time as this boat seemed to run too "level", need to lift the bows, but will try battery move first before adjusting the transom flap.
(http://s2.postimage.org/2h3lf5o6c/P1010111.jpg) (http://postimage.org/image/2h3lf5o6c/)

(http://s2.postimage.org/2h3n2p0o4/P1010112c.jpg) (http://postimage.org/image/2h3n2p0o4/)
Title: Re: Perkasa 49in Renovation.
Post by: Stavros on April 20, 2011, 12:08:10 am
Well I can tell you straight away what your speed problem is without seeing your MTB !!!!! It is not your Motore or even prop size at all it is simply the WEIGHT of the 12v7amp Batts.Just weight them on your kitchen scales and you will see why.

SOLOUTION    Go out and buy some 12Nv 3700 NIMH batt packs.The weight of these is 660grammes so 2 will weigh 1320 or 1.3 kg NOW your 12v 7amperes weigh 2.6 kg so 2 will be 5.2 kg so in all you will save 4.3kg.

Yes I fully understand that 2 of these packs will cost a fair bit BUT if it's speed you want well I am sorry it comes with a price.I already know this to well as I have a perkassa fitted with a MMB 900 motor and run this on 24v BUT it works.WEIGHT I am afraid is the simple KILLER of speed.Yes I do fully realise that LOA,Hull shape etc etc do add up to speed and you will only be able to get a certain top speed out of a hull,regardless of which motor and prop combination that you use.

The main problem with the stick packs is endurance as they are half the Amperage of the gell cells,but they don't drop in performace  as easy as a gell cell.One thing you might want to try if you go down this route is to go back to a 45 mm prop,why am I advocating this,well it will defo help with the run time as the less work the motor has to do  the less amps it will draw,and remember one thing also with the stick packs she will be lighter so the smaller props will probably be sufficient.Just my Personal thought on the matter

.

Stav
Title: Re: Perkasa 49in Renovation.
Post by: 6705russell on April 20, 2011, 07:21:24 am
Problem there is if you do decide to swap the battery to a lighter set-up then you are going to need more ballast to trim it to the waterline again?  Back to square one....

Russ
Title: Re: Perkasa 49in Renovation.
Post by: nick_75au on April 20, 2011, 10:33:13 am
It looks too deep in the water to me, going on the several  Perkassas at our lake, It wont matter even for scale appearance that the waterline is showing, just say if questioned that the boat is at the end of its patrol and has burned off most of its fuel ok2

 Dare I suggest Lipo batteries, the PBs can not output the amps required for any length of time, Ni -XX are now more expensive than Li-po, (15C rated would be sufficient)

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6500

for example

just over 18 Pounds for 14.4 volt 5000 mAH but the correct charger and some form of Lipo low voltage protection will also be required
the closest equivalent from Component shop 12 v 5000 Mah is 40 Pounds.
Total cost would be about 70 pounds, but you would have a charger that can charge any battery chemistry.

My honest opinion, a pair of the battery above (14.4 volts) with a 2:1 reduction on the motor.

I would put a 1.5/2 reduction on the boat regardless of the choice of battery.

With the current set up
At 12 volts the motor should not be drawing more than 12 amps for peak efficiency and the RPM should be 12000 under load
I suspect that the RPM is considerably lower which drives up the amps

Nick
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on April 20, 2011, 11:17:35 am
Great ideas and suggestions guys, but you are all forgetting the one main thing, "Cost". you can't have what you can't afford ! id lurve to go out and buy all the proper kit, but when only doing part time work, you dont get a lot of spare cash left over, so my builds go on a budget.
Thats why i have to try for optimum performance and running time with what i have. if i need more things, i have to budget for months to be able to afford these items.  For example it took 6 weeks to save sufficient to buy the 2 - 50mm props!

The 12v 10 amp/hr battery I have is a mere 8.8 ilbs in weight.

the smaller 12v 7 amp/hr batts are 5.5 ilbs in weight [each].
Title: Re: Perkasa 49in Renovation.
Post by: nick_75au on April 20, 2011, 11:55:20 am
Yes I gathered that from your previous posts, You are probably going to have to settle for a cruiser rather than a speedboat,
As I said definitely the motors need some sort of reduction, this will get the motors working more efficiently, then put the larger props on her, run the lighter battery, when it gets low, bring it in and put the other one in.

Cheers
Nick
Title: Re: Perkasa 49in Renovation.
Post by: ACTion on April 20, 2011, 01:30:09 pm
As Stavros says, you can't operate a planing boat this big with sealed lead acid batteries - the clue is in the word "lead". Most of the motor power is being used simply to push along those bricks.
It pains me to see my dear old Fairey Huntsman designs so often condemned to a canal-boat-like performance because the owner wants to run the model for a long time between charges. It's almost cruel! The same goes for Perkie, and you can pretty much guarantee that every model boat club has at least one or the other sailing whenever you go down to watch.
Fair play to Nick, but I very much doubt if gearing the motors and experimenting with different props will get the thing up on the plane. They were designed for I/C engines, and a pair of SLA batteries is a huge burden compared with a tank full of methanol and oil. Ballast and SLAs are for displacement hulls - this is a gas-turbine powered high-speed warship.
Dave M
Title: Re: Perkasa 49in Renovation.
Post by: 6705russell on April 20, 2011, 02:44:13 pm
I would have to argue that point Dave, my Brave Borderer runs on a 12v lead acid and with the three brushless motors for power it will certainly get to the point where only the back three inches are touching the water, all depends on the powertrain really...

Russ
Title: Re: Perkasa 49in Renovation.
Post by: ACTion on April 20, 2011, 04:41:48 pm
I would have to argue that point Dave, my Brave Borderer runs on a 12v lead acid and with the three brushless motors for power it will certainly get to the point where only the back three inches are touching the water, all depends on the powertrain really...
Russ
All things being equal I'd have to agree, Russ - but the scenario is not to change the existing brushed motors as the guy is on a strict budget. My point is that he won't be able to obtain planing performance with his existing combination of motors, SLA batteries and ESCs, irrespective of adding gears and/or changing props. Three brushless motors and their ESCs would be well beyond both his budget and the scope of the question posed - but pretty spectacular and a sight that would do this old model designer's heart a power of good!
Dave M
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 on April 20, 2011, 08:06:41 pm
the motor setup I have installed WAS suggested by a forum member on this actual site in the first place, so Im not complaining, KIndly remember the pictures posted are NOt at full speed, they were only taken whilst the boat was using the throttle adjustment on the joystick [set at full adjust].  WELl, how else can i take a picture at full throttle, not unless you are fortunate enough to have someone standing around who will do the job for you.  those pics were purely to check its level line and see how the transom flap were performing.
Some people just jump straight in with both feet, I always find it better to read all the story then look back at the pictures on anything i do.

Works for me!

Im not expecting a rocket ship, I know and appreciate that, simply due to my financial budget, but it does not stop me from enjoying my hobby at a level I can personally afford.  its still far better to see the boat out on the water than gathering dust in an attic for several years, whilst funds allow a better drive train. Ive fitted what i can afford and can still get some enjoyment out of the renovation, whilst  my piggy bank develops.
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 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".
Title: Re: Perkasa 49in Renovation.
Post by: treeboa 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
Title: Re: Perkasa 49in Renovation.
Post by: Andy_k 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

Title: Re: Perkasa 49in Renovation.
Post by: gregk9 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.
Title: Re: Perkasa 49in Renovation.
Post by: gregk9 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.
 
Title: Re: Perkasa 49in Renovation.
Post by: Gazza 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
 
(https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-ash4/248058_627507020612042_557526051_n.jpg)
 
And this baby to make it go LOL
.
(https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn2/969392_627506650612079_1084378123_n.jpg)
 
Title: Re: Perkasa 49in Renovation.
Post by: bubbletop409 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.