Print

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

[dondecap]

hi guys.
wow you're motoring on with this ......very good build going on there.
I have only got as far as 'looking at the plans'  for my rescue tug............. still a long dark winter ahead me thinks..
keep up the good work.
:)
regards
don

[Dan.Lord]

Hi, rally great build comming on there, I lke this craft, looks menacing. I took a couple of pics at Hendon several years ago, might be of interest. Also there was a film made with Dirk Bogard about the RAF Air Sea Rescue, called "The sea shall not have them", it was filmed off Harwich, really good , they used this type of vessel. I might still have it on Video, & could transfer it to dvd if interested.
I've never built a wooden boat before, might be a good one to start on. I see these on ebay now, enquired about the 1/12th version, £200.00 & 68" long, so a big beasty, might be better going for the smalller one  

Cheers Dan.

[MikeA]

how did u manage to keep that boat in such good nick after 50 years!! were you planning on leaving it that long and sealed it in a air tight safe?

[howyson]

JB - I would like to see the other photos if it is not problem. It looks to be a great model.

I first started building the model when I was seventeen. My parents had a old summer house that became my workshop. I completed the basic hull and the shells for the two main susperstructures but could not afford the two Taycol meteors I wanted to install. Shortly after my parents moved house and it was relegated to the garden shed. Unfortunately the shed was not locked and the model was stolen. I restarted and got to the same stage and then went off to University and the model was moved to the attic. When I married the boat moved with us but was again relegated to the attic. I always intended to restart but whilst working, raising a family, repairing the car, doing the garden etc. I never found the time.
So it was not until I retired that I brought it back down from the attic, it was a bit dusty but suprising not too worse for wear. There was a gash on the starboard side of the hull, hence the patch, and a few other minor dents and on the superstructure the ply and started to come unstuck in a couple of places.

Dan - Amazon have a copy of the video for sale, save you the hazzle, but thanks very much for the offer. I have found the 34 inch long to be big enough, any bigger and I would need to build a workshop in the garden to house it!

[MikeA]

its in brilliant condition considering.

[howyson]

I had hoped to post before now but been so busy. The photos refer to the rstructure fitting. Never thought of magnets, re 'kitshack vosper RTTL'. the first photo shows foreward 'hooks' and slot for rear hook located on superstructure. The second shows super stucture in place, the third the 'hatch' used to retain the superstructure and the fourth the system complete, (excuse the door on the on the superstructure as it was originally centered until I found out that it should be offset so was just checking the filling by giving it a rough undercoat).

The last photo shows the aerial array. The radar 'dish' is missing as I have been in a quandary as to what number to assign to my model, ie 275?, I have looked at many photos and it becomes very confusing as there are conflicts, ie on the 2754 the egine room ventilators vary from foreward to aft of the engine room superstructure, possibly due to refits? After much time deliberating I have finally decided to stay with the model maker plans and opt for 2754. However the detail for the complete radar array is limted and I would be very grateful if anybody can supply more info. I am hoping that I might make the 'dish' sufficiently light so that I can take embed a digital watch mechanism in it so that it will rotate once a second, (possibly a bit fast). Anybody know of any other 'micro' motors?

[scout]

Ask your local library if they can get the book  Sailors of the RAF  various rttl and a s rescue launches in there I was lent a copy when building one for a chap who served on one several times when he was in the RAF. As he has now past on his wife has donated it to RAF Cranwell hope this helps Yours Scout 

[howyson]

Thanks Scout for the title and advice, will definitely give it a go. Unfortunately the old photos tend not to have sufficient resolution to give the required detail, however combined with the shots I have it might be possible to get a better idea.

I must apologise for my 'senior' moment, the second hand rotates at once a minute, and it will be a analogue quartz movement not a digital watch!!!

I am wondering whether my choice of 2754 is a good one as the original sank. My son thinks that my model will sail out into the centre of Paddy Freemans pond where it will then sink!

Howard

[howyson]

Definitely had a senior moment expecting to use an analogue quartz clock as the drive for the radar dish. Bought a second hand watch for £1 for experimentation and found it was incapable of driving anything more than the second hand. Blinded by the fact that the small size was ideal.

My second thoughts were the tail motor on a small model helicopter. So I bought a Syma S107G for experimentation. It only cost £25 and I was really impressed with the overall performance for the price. So much so that I was reluctant to butcher it for the for the tail motor. Anyway my son commandeered it so, as spares are readily available, I have told him to buy me a spare tail section leaving the model intact. The motor is a little longer than I would have liked but I think I can just accommodate it. Hoping that it is a conventional electric motor i.e. not one requiring drive electronics!

Howard

[Circlip]

Bit late Howard but this may be of help for future use :- http://www.gizmoszone.com/shopping/agora.cgi


    Regards   Ian.

[MikeA]

are you talking about those tiny motors bout the size of fag tip? i got a few of those i wouldve sent you some for a the cost of a stamp

[howyson]

Thanks very much for the link Ian, it is now added to my favourites list, will be getting some business in the future.

The tail motor is 4mm dia with the body, excluding shaft, 12mm long. As I said the length is a little long so I am tempted to go for the 4mm * 8mm from Gizmo unless you have one that size Mike. I am prepared to pay you the going rate.

Howard

[MikeA]

nah dont have 1 that small. i salvaged them out of my own mini rc helicopters so you couldve had em for a nothing. Thought id have a use for them one day but seems not.

how are you going to slow down the rpm?

[howyson]

Good question, at the moment I have a couple of ideas but until I can experiment with the motor I am not sure. It depends on how it performs at low voltage, i.e. whether it wil provide enough torque at a low enough revs to require llimited gearing. Otherwise I might have to put in a timer to pulse the motor, say every second, to effectively slow it down, (unfortunately this might be noticeable in the movement of the 'dish'. One other alternative is to buy one of the geared motors form Gizmo but the one with sufficient gearing is quite long and will be difficult to incorporate into the array.

I must admit that each time I look at the plans I wonder whether I am being a little too ambitious. The only other thought is a flexible drive but that would have to be very small in diameter and there is propably nothing like that available.

Any thoughts

Howard

[MikeA]

if i were to do it i would use a flex drive. what i would do though is use a peice of wire seeing as torque wont need to be great then run that through an aerial tube. or something like this:

http://www.ebay.co.uk/itm/PTFE-TUBE-SLEEVING-TW11-Translucent-White-2-4-Bore-/190483205643?pt=LH_DefaultDomain_3&hash=item2c59af0e0b

[howyson]

Thanks for the input, and the link, I think you could be right about the flex drive. However I am in Spain at the moment so cannot make any decision until I return. Will post any progress then.

[John W E]

hi ya there Howyson

sorry for delay in answering your personal message - bit sidetracked - but here I am now.    With regard to driving the main radar on the RTTL; the way I was planning on rotating the radar on the model I built was using a thin, clear, acrylic plastic rod - up the centre of the mast from the cabin roof - attached to the radar on the top and using the small gear assembly which I bought from ACTion located inside the cabin.    With the rod being of clear acrylic and only 2mm diameter, it was difficult to see - unless scrutinising it.    However, I abandoned this idea - as it was a bit of a 'weight' issue with all of the gear I had previously installed in the model - such as sound units, amplifiers, speaks and soforth.   I was becoming concerned, so, the thought of adding extra powerpacks was a bit offputting.

However, it is another thing to ponder over.

keep on with your good build.

Aye
john e
bluebird

[howyson]

Thanks for the input Bluebird. I have not got the restraint you have so it is a possibility. Plenty to think about before my return!

[irishcarguy]

Hi, you have a very nice build going there. Thinking of how to operate your radar, I did it much like Bluebird suggested. I hid the geared motor inside the bridge of my Smit Nederland & made it look like some of the bridge equipment, not quite to scale but it looks nice working. I got the geared motor from Cornwall models. I put a ball race inside the radar dome to cut down the friction, it works great up to now.The bearing came from an old VCR. Mick B.

[howyson]

Thanks very much for the comments and advice. When I originally started the model the intention was not to go into such detail, the net was not around to get such info, but after I restarted I have become more obsessive as the build has progressed.

I have copies of the appropriate sections of the plans here togther with my 'RTTL photo album' on a portable HD, so I have at least been able to do a bit more investigation into the best approach. As I have not put 'full' windows in superstructure, (part of the initial build), the motor and gearing will not be seen. The aerial tripod has various cables and a cable tray so hiding the drive shaft should not be too difficult.

[dodgy geezer]

Servos are now so cheap, it is worth getting a micro one, taking out the electronics and the internal stops and using that as the radar base. Here is an example at £3....  http://www.giantcod.co.uk/dys0301-micro-servo-torque-p-403862.html 

[howyson]

Thanks very much for the info. Excellent piece of kit, Already signed on and one servo with a set of ball bearings, for radar dish shaft, in cart for when I return.

[dodgy geezer]

The gearing is all there - you just need to take the internal stops out. If it runs a bit too fast, drop the voltage with a small resistor or diode in the power line.

If someone knows a bit about the internal electrics of a servo I suspect it would be quite easy to plug the servo into a spare channel, and turn the radar on and off that way....

[howyson]

That is another task, to upgrade the R/C. The system I have is only a 2 channel unit I purchased when I was in Hong Kong some thirty years ago, (in anticipation of finishing the build before now!), so not quite up to the job. I have added LEDs to the searchlight and navigation lights so definitely need more channels and now possibly one for operating the radar. If the internals cannot be modded then as an extreme solution another servo could be used to operate a simple switch. Obviously I need to swot up on R/C systems and accessories to see what the latest sytems do and what will be most suitable for me.

[John W E]

The gearing is all there - you just need to take the internal stops out. If it runs a bit too fast, drop the voltage with a small resistor or diode in the power line.

If someone knows a bit about the internal electrics of a servo I suspect it would be quite easy to plug the servo into a spare channel, and turn the radar on and off that way....

hi there, I am afraid that it is a little more complicated than just removing the physical stops inside the servo, to produce a continuous rotation of the servo.

You also have to disconnect the mechanical drive to the variable resistor (potentiometer) (volume control ) inside the servos.    Normally this is connected directly underneath the output drive of the servo.   If you do a google search on modifying servos there is plenty of stuff out there - showing various different ways with different servos.

Also, using a servo to drive a radar will draw current continuously from the power supply which supplies your RX.

http://www.acroname.com/robotics/info/ideas/continuous/continuous.html
http://www.youtube.com/watch?v=BM_xm7dLSyI

hope this is of some help

aye
john