Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[tjfromdevon]

Well, whilst awaiting delivery of speed controllers for my MAS PT R/C Conversion I made a start on the Elco conversion. Began with the drive and steering gear as usual. Hand fabricated the rudders from brass stock as I had to scale them up slightly as the kit ones (to scale) were teeny - if I had used them the turning circle would probably replicate that of a Gulf Oil Tanker.! I increased the size by aabout 50%, bases on previous boat builds. The white cones in the picture will be epoxied into the hull and the rudder posts will come up through them - the cones are form the SHG rudder kits which i found a bit chunky - hence the fabricated ones. I did get round to soldering them together - next job will be to epoxy them into the hull and then tackle the prop shaft mounts.

[tjfromdevon]

After I finally finished messing about with my Italeri MAS Boat, I have fabricated the tiller arms and linkage for the three rudder, I also finished the prop shafts after getting a mate to turn me some 2mm prop shaft bearings from 1/8 rod. I soldered these into the tubes today - doesn't sound like much but seemed to take forever. Next job will be to fabricate the six P mounts for the shafts.
i did manage to sail my Micro Magic for a couple of hours down at the lake as well - all in all a pretty good weekend. Will post more info and pics later.   

[tjfromdevon]

Here are the photo's of the control arms I made for the rudder assembly

In addition I have also temporarily fitted the 'P' mounts supplied with the kit to the underside of the of the boat. These will be used to align the prop shafts correctly,


Once the prop shafts are in I will remove the plastic ones and replace them with the brass ones I have begun to make. I have cut the pieces out and just have to silver solder them together


Motors and ESC's arrived yesterday as well. The motors are water cooled 3000Kv outrunners. The ESC's are 70amp water cooled ones as well - all sourced from Hobby King, who I use for just about everything electronic.

[HelgeBe]

Looking forward to see the shafts in place.

What speed are you aiming at with those motors?

HelgeBe

[tjfromdevon]

Not sure at the moment - it will depend on what size Lipo I use - originally I was planning on using a 3s pack at 11.1v, but that would give me about 33,000 rpm per shaft - i think the boat might go orbital at that speed! and I'm not sure the shafts will take it, so I will probably start with a 2s pack at 7.4v, that will deliver about 22,000 rpm per shaft which should still be plenty when multiplied by three props. The boat should certainly plane when finished although it probably will be a bit above scale, but I'll just have to wait and see.
Thanks for the interest

[HelgeBe]

It will certainly go like a rocket!

I have the same boat. I have used 2 x 1600 Kv motors and are now swapping between 7,4 and 11,1 V LiPo. 7,4 make it possible to fine maneuver at very low speed while 11,1 gives a astonishing top speed. Maybe discussion here can be to assistance: http://www.modelboatmayhem.co.uk/forum/index.php?topic=29702.0

HelgeBe

[tjfromdevon]

Been a bit of a lull in building over the last ten days or so as I have been on holiday - camping in Cornwall, weather was great and I actually got a bit of a Tan. Anyway back to business. I had my fist attempt at silver soldering with the prop shaft 'P' mounts and I have to say I'm pretty happy with the results. I have cleaned them up and filed an edge to them to give them a vaguely aerofoil shape. The next job is to install them when I have a little more time.

[gregk9]

Be careful to always re oil/lubricate all the propshaft bearings if I were you, especially running brushless motors at the rpm's you are considering, stainless steel shafts in brass bearings/ brushless rpm's  can generate a fair bit of heat.
I run standard brushed motors and always re oil after each trip to the club water.

You may also wish to increase the size of the rudders too, especially if you run all three motors in a turn, you have a fair bit of power wanting to propel the boat in a straight line, so you may need more rudder to get the boat to turn with more control, either that or you may need to switch the inner motors off in a turn, allowing the centre & outer engine to turn the boat.

I used micro switches on the rudder servo to switch my "outer" motors off in a tight turn and works well, especially as I dont think anyone makes a "mixer" unit for brushless controllers yet?

Unless someone can prove me wrong here?

[HelgeBe]

There is no need for special mixers for brushless controllers. A separate standard v-tail mixer or a programable radio will do the job.

HelgeBe

[tjfromdevon]

Yep, I was thinking about using a mixer for the two outer motors so they are on one channel and then mixing the outer motors and the centre motor using my 6 channel radio - hopefully that should work!

[Shipmate60]

The only time I use mixers is for 3 shaft models.
Only because I keep getting the centre shaft control mixed up and end up with 2 going ahead and centre shaft full astern!!!

Bob

[tjfromdevon]

Well I've had a few busy nights and cracked on a bit with fitting the hardware. The 'P' mounts and prop shafts were installed, followed by the motor mount and motors. The motors were a bit ticklish as on of the intake fittings for the cooling system sheared - they are aluminium and very fragile. I had to replace with some annealed brass epoxied into the hole - hopefully this will do the job, I have yet to test it's water tightness!.

The area with a small wooden frame is going to be back filled with Body filler to beef up the 'P' mount installation.

[gregk9]

be careful you have not reduced the internal diameter of the water cooling pipe, as any restriction in water flow may cause the motor to overheat as it will not get as much water passing through.
its far better to put a tube/pipe over the outside of the broken item where possible, rather than reduce size inwards so to speak.
merely a "cautionary note" , but have seen many a motor burn out due to lack of cooling water flow.

[tjfromdevon]

Unfortunately the inlet feed sheared where it feeds into the motor so there was no stub to fit anything to. These motors are notorious for this. If it becomes a problem I may just run with two brushless motors as the wing motors and then fit a conventional brushed motor and ESC to the centre shaft for lower speed manouvering - these are 3000Kv motors and experience suggests that the boat will still be quick just with two of them rather than three!

[HelgeBe]

Very nice set up of the shafts!

Can you give little more details about the diameter of the propellers, shafts and tubes, and if you are using any bearings in the tubes?

I do not think you will need cooling at all on these motors. You will only utilise a fraction of the power available.

HelgeBe

[tjfromdevon]

Prop diameter is 20mm, shaft diameter is 2mm. The prop shafts have bearings in them but the prop supports are just brass rod, hope that helps.

[tjfromdevon]

Well I finally managed to sort out the electronics, all three speed controllers have been installed as well as the steering servo. The controllers have been programmed and tested for direction in the bath, the only thing left to do now is to install the cooling but I'm waiting for delivery of some intakes - this will mainly be for the ESC's. The boat will definitely be below scale waterline, but that shouldn't be too much of a problem based on previous experience. Once the cooling is in I will trial fit the deck to work out hatches etc.

[tjfromdevon]

Well after a bit of a break due to this insane weather and getting my son back to Uni, I have managed to do a bit more on the conversion.

I removed the centre motor and ESC as I think it may be superflous 'cos when I ran the motors they didn't 'arf bat around!

I fitted a flush water intake for the cooling, i'm just waiting for the outlet fittings to arrive. I have also put together the three main deck modules and attached them together as one unit as I want to be able to remove the centre section for battery charging etc. The main deck will be screwed down as per the instructions and will only be removed to give access to the rudder servo and steering linkages. I have also fitted the retaining frame underneath the deck. I have also fitted a foam seal under the deck to give a water tight seal. I found with my Italeri MAS boat that it shipped a lot of water through the deck hull joint until I fitted a seal. The next job will be to construct and paint the various modules. I will post more photo's of this as I proceed.

I will be at the RC show at RNAS Yeovilton on the 22nd October with the North Devon Marine modellers and will be taking this build with me if anyone is interested.

 

[tjfromdevon]

The rest of the cooling equipment arrived this week, so today I managed to get the boat on the water running on just two motors - it's INSANELY quick, which is just what I was after!. Next part of the build is to remove all the shafts and electronics and continue the build. I will post more pics as and when I progress.

[Martin (Admin)]

Looking Good!   

Have you found any smaller trust washers yet?

[The long Build]

The rest of the cooling equipment arrived this week, so today I managed to get the boat on the water running on just two motors - it's INSANELY quick, which is just what I was after!. Next part of the build is to remove all the shafts and electronics and continue the build. I will post more pics as and when I progress.

Looking at the set up, Have you thought of adding wings !!

[tjfromdevon]

Yes - I was having a look through my 'small parts' box - and I managed to find some

[tjfromdevon]

After testing the boat on the water last week I have finally managed to actually get some bits painted. The problem with doing a conversion from a static model like this to an R/C version is that you have to plan the build in a different way from that specified in the kit instructions, this means some of the painting and detailing that you would do at the beginning of the build can only be carried out toward the end.

After testing the boat and seeing just how fast it's going to be I have decided to run it on the water with only the centre propshaft and prop. I will fit dummy shafts and props when I take the boat to exhibitions - at least it will give me some running equipment for the S-Boat and the Vosper (when it's released).

Our Boat club Chairman is also currently building PT596 as an RC conversion. He is building his as per the kit from the box. Not wanting to have two identical boats in the club I had made the decision to build mine as one the RON29 boats. This was the ELCO squadron that served in the Mediterranean, to further complicate things I am going to build the boat as one of the four from this squadron that carried the Thunderbolt gun system. This will be scratchbuilt. However this means that the colour scheme will be Thayer blue for the Hull and other vertical surfaces and Deck blue for the deck etc. I have had to mix my own paint using a chip colour I found on this site http://www.steelnavy.com/usnchips.htm. This is modified Measures 16 (according to John Lambert's Coastal forces book).

So here are the photos of progress so far. One is the Hull after spraying, together with the exhaust mufflers, gun turret components and shots of the deck and cabin. The keen eyed of you may notice that the smoke cannister is at the rear of the deck rather than along the side of it - this is because on the RON 29 boats the torpedoes were set further back and the cannister repositioned.

Finally if anyone is interested I have been using Revell Aqua Acrylics to paint with - I am gradually changing to these from Humbrol enamels - I water them down with distilled water and they seem to spray really well at around 30psi.. That's it for today.

[longshanks]

Nice crisp looking build there. How are you planing access, whole deck or cabin sections?

Are the 0.50 cals original or after market, they are looking good.

Which Devon club are you with?

Keep up the good work 

[tjfromdevon]

For deck access all the cabins have been glued together and a coaming fitted. If you take a look at some of the earlier photo's you can see how I've done this. The deck will still be removable to allow access to the rudder linkages, servo and receiver - but I'm not anticipating this being a regular occurrence.

The .05 guns are from the kit, they have been painted using Tamiya Gun Metal paint, and I am with the Ilfracombe and District Model Boat Club.

Thanks for the positive comments.