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[Martin (Admin)]

Via email to Mayhem ... anything I overlooked?

 Hi,
 I have inherited 2 model destroyers built in the 1950's from old tin cans.
 The radio controls are past their best and I'd like to upgrade to a more modern system.
 I don't have any knowledge of R/C and would like some advice.
 To completely replace everything ( motor, receiver, transmitter, batteries) what would be the best/cheapest route to take?
 Many thanks in anticipation.
 C

----------------------------------------------------------------------------------------------------------------------

All Looks OK in the photos, here "my" list of recommendations:

1.    Decaperm 12v.That is a very nice motor!
2.    Do a float test. Check for leaks etc. to see where you are.
3.    Loosen the main motor gear & unscrew the motor wires.
4.    That gearbox looks adequate but noisy, use small blobs of grease, not oil.
5.    Check the prop shafts turn smoothly by turning over with your fingers
6.    Withdraw the shafts to check for trueness and rust. Use 3-in1 type oil.
7.    Connect a battery (3v - 6v) direct to the motor to see how smoothly it  runs.
8.    Replace the rudder servo. Any “standard” servo will do eg. Futaba S148 Servo etc.
9.    Replace the radio with modern 2.4Ghz 2 channel set, Skektrum, Futaba, Hitec, Planet, Accoms are reliable names.
10.  I quite like the Micro Gyros speed controllers, if it works, excellent!
11.  The Speed controller will need a new signal plug to match the new radio.
12.  Replace all the wiring, batteries, connectors etc.

        That should give you enough to ponder for now!

         Regards,
          Martin – Model Boat Mayhem

[HMS Invisible]

Via email to Mayhem ... anything I overlooked?

I think the decaperm motor has a suppressor network fitted. Not certain though, so check.
Sets of polarised connectors on batteries and esc .
A 10 amp blade fuse and holder on each 12v battery +ve wire.
A 3 amp polyswitch between esc and motor. This "open circuits" on a stalled motor, before a main safety fuse ruptures. It cools and resets unlike a one-time fuse.
Optional one amp on/off switch wired into the esc red loop.
The esc won't turn the motor on battery connection or on loosing signal without one fitted however.
Enamel insulation varnish inside esc in case of condensation. Air dry the model internals after use.
I would just get new transmitter NIMH cells then do a range test and keep the 27 MHz set if there are no problems.
The esc filters out & warns of radio glitches but continues to work until total signal loss.

[Martin (Admin)]

 
http://www.ebay.co.uk/bhp/resettable-fuse

[HMS Invisible]

Fair enough. A good find. I don't think those breakers automatically reset like polyswitches do. That is an important consideration for the submarine modellers.

 Going off the original topic somewhat, if the illustrated 10-25 amp breakers give galvanic separation they would be ideal for the main fuse in scale boating. Check the manufacturer data sheets because you don't want nuisance tripping if you habitually slam a motor in reverse. Websites like Farnell and Digikey should have manufacturer datasheets on both these device types.

  Auto resetting polyswitches have solder connections and look like large square capacitors. The 16 volt series below 10 amp have a speed and hold/trip ratio that makes them well suited to motor stall protection protect a motor in the event of a fouled prop on a submarine. Unlike the main fuse on a battery they are not essential.

I now see Ebayers selling 10-packs of the larger (and slower acting) 30v polyswitch series when following Martin's link to breakers on Ebay.

[Brian60]

The radio gear and some of the wiring is fairly new -late 80's by the look of it - crimp spade terminals are a giveaway as is the Acoms bits, I had a couple of those servos in storage, they had seized as the gears were brass but the shafts were steel.

For the price of a cheap radio system nowadays, it shouldn't cost too much to get them back on the water. I think I would be tempted to take out the Decaperm and sell it, they go for good money nowadays especially in Germany, then install maybe a generic 540 or 700 sized motor.

[Martin (Admin)]

then install maybe a generic 540 or 700 sized motor.

... a 'slow' revving,  540 or 700 sized motor!

[TailUK]

The radio gear and some of the wiring is fairly new -late 80's by the look of it - crimp spade terminals are a giveaway as is the Acoms bits, I had a couple of those servos in storage, they had seized as the gears were brass but the shafts were steel.

For the price of a cheap radio system nowadays, it shouldn't cost too much to get them back on the water. I think I would be tempted to take out the Decaperm and sell it, they go for good money nowadays especially in Germany, then install maybe a generic 540 or 700 sized motor.

I'd agree with Brian.  The single motor and gearbox means your shafts are both turning in the same direction.  It would be better if they counter rotated with left and right handed screws.  Also make sure if you convert to 2.4 Ghz that you can get a signal through the sheet metal hull.

[malcolmfrary]

Is the superstructure metal as well?  If going to 2G4 it might need a receiver with a long enough aerial lead to get the working end into clear space.

[dave301bounty]

that is a fantastic build ,just shows what can be done with old beans tins .well done .

[pugwash]

A nice model of HMS Cadiz of the Battle Class - a bit of tweeking and and some more detailing and it
will be a cracker.
Geoff

[grendel]

the gearbox has more than a hint of meccano about its appearance.

[chas]

Surely the shafts are contra rotating, no problem there. If the motor is OK, why change it, that will probably mean changing the gears and drive. If it ain't broke, don't fix it. New 2.4 gig gear is great, provided the signal penetrates metal superstructure, that's something I've never checked, but I would expect it to be OK. It's water that causes the problem because of signal attenuation.
Chas

[Pat Matthews]

More pics of both PLEASE!

[malcolmfrary]

Surely the shafts are contra rotating, no problem there. If the motor is OK, why change it, that will probably mean changing the gears and drive. If it ain't broke, don't fix it.
New 2.4 gig gear is great, provided the signal penetrates metal superstructure, that's something I've never checked, but I would expect it to be OK. It's water that causes the problem because of signal attenuation.
Chas

Metal is great at reflecting and redirecting radio signals at any frequency.  Put a WiFi router inside a big biscuit tin with the lid on, note the lack of any signal outside the tin.  Water is good at absorbing ultra high frequencies like 2G4, which is why microwave ovens work as well as they do.  Like I said earlier, if 2G4 is to be used, care will need to be taken to ensure that the active bit of the aerial is not hidden by any of the metalwork.
I don't see an extra gear in the path from the motor pinion to either shaft, so both shafts will rotate the same way.  The gearing looks like there is a slow revving motor with the shafts geared to rotate faster, the opposite of what we now see normally.  Back then, just having it move was a bonus, if it is to perform like a destroyer, re-motoring is probably needed.

[MikeK]

Surely the shafts are contra rotating, no problem there. If the motor is OK, why change it, that will probably mean changing the gears and drive. If it ain't broke, don't fix it. New 2.4 gig gear is great, provided the signal penetrates metal superstructure, that's something I've never checked, but I would expect it to be OK. It's water that causes the problem because of signal attenuation.
Chas

Agree with you Chas (After a little aerial finger waving  ) Both shafts are contra rotating


MikeK

[RAAArtyGunner]

Agree with you Chas (After a little aerial finger waving  ) Both shafts are contra rotating


MikeK

I thought so too, until Malcolm pointed out they are not.

Draw what is there and they are both going in the same direction.

One main gear turning two small gears going the same way.

[warspite]

Agree with you Chas (After a little aerial finger waving  ) Both shafts are contra rotating

Ahh the old grease song - you're the one that I want - finger dance

[Shipmate60]

The shafts turn the SAME way.
You need an idler gear as Malcolm has said to get contra rotating shafts.
They BOTH turn opposite to the driver gear.


Bob

[chas]

I didn't expect to open a can of worms. I sat down, drew 3 circles, and went to wash the egg off my face. Sorry chaps, I got it wrong.
 If this were my model, I would connect a battery to the motor, put it in the bath and see what happens. As pointed out, the ratios are weird.
It's going to be great when resurrected though.

[raflaunches]

Amazing what can be done with some old fashioned metal bashing
Definitely worth spending the time getting these little beauties working again.

[TailUK]

Props should Counter Rotate not Contra Rotate  The first should indicate that the two props on two separate shafts rotating in opposite direction.  Contra Rotates describe two props on a single shaft, each turning in a different direction (like the propellers on a torpedo). 

[MikeK]

I didn't expect to open a can of worms. I sat down, drew 3 circles, and went to wash the egg off my face. Sorry chaps, I got it wrong.
 If this were my model, I would connect a battery to the motor, put it in the bath and see what happens. As pointed out, the ratios are weird.
It's going to be great when resurrected though.

Don't be too concerned Chas there are a few more eejits out there to keep you company ! I too gave up my budding orchestra conducting training and instead drew three circles and arrows - magic !
Is there a way of cleaning egg off shirt front that dripped off face ! 


Mike