It’s been a while since I posted my last update of the new fire monitors but for those of you that are interested Vintage Model Works have introduced an extended range of fittings for their 46” Crash Tender including the new monitors that I modelled for them.

The new fire monitors that they asked me to provide patterns for are now available for just £14 plus P+P for the pair.

There’s also a very comprehensive set of parts for the salvage hoses for £23.50 plus P+P and also a completely new tow bar kit that that has been accurately modelled at a cost of just £15.50 plus P+P

Sadly, I can’t claim to have produced the patterns for the hoses or the tow bar, they are the work of a professional model maker and far better that anything I could make!

I might add that I don’t have any commercial connection to VWM and I produced the new fire monitor patterns purely for the prestige of making a better job than those that were made so many years ago.

All of these items can be seen on the VMW website on the accessories page:

https://www.vintagemodelworks.co.uk/?page_id=39

My first task is to clean up the white metal castings to remove any casting marks and blemishes and to key the surface for a good paint finish.
I have decided that the best way to assemble the monitors is to drill a 3.2mm central hole through the base part to accept a threaded rod which will then hold the top piece firmly.

It is not possible to drill white metal as a drill bit in an electric or hand drill will very soon seize and snap, but the trick is to put a drill bit in a hand chuck and bore the hole a few turns at a time, withdrawing the bit to clear the swarf produced and then continuing.
This is quite laborious work but it is the only way to bore a hole through white metal to any depth.

I did fully drill through the base and to my relief the exit hole was pretty much centre of the casting and I was then able to put the upper casting in place and drill a shallow hole in the top part which was then tapped with a 3mm thread, again this tap had to be done a few turns at a time withdrawing the tap frequently to remove the swarf.

I could then insert a 3mm threaded rod through the castings to pull the two parts together, with a nut on the bottom of the base, in a recessed hole, both with some Loctite threadlock to keep them tight.

To add some extra detail to the monitors I used a couple of steel washers and a plastic spacer between the top and bottom parts to simulate some flanges that are on the real thing.
The white metal casting of the operating handles is a little bit fragile but they will withstand a single bending to introduce the crank that raises the height of the handles for the operator.
I had made the handles for the pattern in brass for strength so I’ll have to see how they fair in the much softer white metal.

The handles are attached to the side bosses of the top hose part using some 1.2mm brass screws, again I very carefully tapped the holes that I made through the casting to get a secure fixing for the handles. The excess brass screw was cut back and the screws re-fixed with a dab of Loctite to ensure they stayed tight.

The new fire monitor kit is actually supplied with four tiny white metal screws for attaching the handles but in my view they are unsuitable to provide any kind of firm fixing and hence my use of proper brass screws as used in my original pattern.
Another small detail on the monitor base is an operating lever that presumably is foot operated to allow the monitor to be unlocked from a centred position and allow the monitor to be rotated to the desired direction, that’s just a guess as I really don’t know the true purpose of that lever!

I made this lever from a short length of brass rod and finished with a small round brass bead on the end. This piece was bent to the correct shape and then epoxied into a hole drilled into the underside if the base.

A side-by-side comparison of the old and new monitors was satisfying to see as the new pattern looks so much more true to the real ones.
With the monitors fully assembled I cleaned them thoroughly with some panel wipe to remove any grease or contaminants and then gave them a light coat of primer.
I had some etch primer to hand so I used that although I don’t think it’s particularly effective on white metal.

The final coats of red acrylic were applied and then some black to simulate the hand grips and finally some ‘bronze’ acrylic for the nozzle at the end of the hose.

When fitted to the boat the monitors look so much more realistic, I hope you would agree?

Vintage Model Works are also introducing some other new fitting for their 46” RAF Crash Rescue Tender to replace older designs and I’ll post some pictures of them in another update.

Some while ago I was asked by Vintage Model Works to make new patterns for the fire monitors which are quite characteristic to the RAF Crash Rescue Tender. The current type supplied with the VMW kits are based on a very old pattern from the early days of the model when it was produced by AeroKits many years ago.

I took this as a great honour to be asked and I set about finding as many photographic references, original drawing and early film of the boats in action.

Of particular use was a video from film taken by Pathé, a newsreel company, when the boats were demonstrated to the public, and one sequence showed the fire monitors in action and some very usable detail of the construction and scale.

Having gathered as much detail as I could find I made some scale drawings of the monitors as I perceived them and worked out, as best as possible, the correct scale for the 46” model.

As I don’t have any metal turning experience or equipment I decided that the best material to use for the new patterns was plastic, particularly as some of the parts would need to be heat formed.

I made up a small wood former around which I could bend heated Plasticard rod around to form the distinctive curved shape of the top of the monitor.
This took multiple attempts until I made a satisfactory shape which will still need some filing and shaping to refine it.

With the hardest part out of the way the remainder of the pattern was relatively easy to make by ‘turning’ the rest of the parts for the body and the base in an electric drill chuck against some files and abrasives.
Small details were easy to add such as the reinforcing fillets between the circular flanges and the main pillar and also bolt heads which were made from short sections of hexagonal plastic rod. I added some blocks to the curved part to form the mounting base of the operating handles.

The operating handles themselves were made from some 'D' profile brass rod and they attach to the body of the fire monitor with very fine brass 1.5mm screws.

Once I was happy with the final result I supplied the pattern to VMW for approval.

Sometime later I was sent some samples of the white metal castings to evaluate and to my delight they had turned out quite well with a minimal amount of flashing to file away.
Remarkably they had even made white metal casting of the screws however I don't think they will be strong enough to be used to fix the handles to the monitors.

Next part….assembling and finishing the new monitors.

The motor compartment in the boat is quite large and thus a reasonable volume of air surrounds the motor and despite never having any motor overheating issues previously I did decide to add a fan onto the end of the motor shaft to introduce a bit of air circulation.

This is something that I did on my VMW Thames River Police Launch where the motor is enclosed in quite a small box and benefited from the forced ventilation. It’s not that the Crash Tender really needs it, but more that I have another small computer fan of the right size and that it is so easy to do!

Disassembling the fan is quite brutal but necessary to extract the fan blade in one piece. A hole was then made through the fan at dead centre to the exact diameter of the spigot at the end of the motor using a reamer. The Turnigy Aerodrive motor comes supplied with some extra metal parts for attaching an aero propeller when the motor is used in an aircraft.

The piece is easily re-purposed by cutting off the threaded stud and grinding/sanding the face to a flat and smooth finish, and then it's fitted over the spigot on the end of the motor and secured with the three cap screws which are also supplied with the motor.

I operation the fan is either pushing or pulling air through the motor and stator depending on the direction of rotation, and in either event it is stirring the air in the motor compartment.

This mod seems to add no extra load on the motor, no additional bearing strain, no extra noise and if you’ve got the bits, no cost!

The new LiPo batteries are not supplied with any type of connector, so that the user can supply and fit whatever they prefer to use. In my case it was XT60 for all the battery connections but for this refurb I chose to upgrade them all to XT90 to allow for higher discharge rates.
Fortunately I already had sufficient XT90 connector sets in my ‘electrical bits box’ and I soldered these onto the new LiPo batteries, using extreme care to avoid shorts and heat shrink sleeve to insulate the connections.

As the old NiMh batteries were arranged in a series connection I had to modify the cable loom for the single battery connection and re-terminate the fly lead to the battery with an XT90 connector.
I have left the in-board charging facility unchanged as that would require a quite unnecessary change to the entire wiring loom and switch panel. I will be charging the new LiPo batteries, in a fireproof charging 'pouch', on the workbench for safety.

Because the receiver will now be powered from the BEC in the speed controller I have put the (red) 5v supply line of the speed controller back into its 3 pin connector so that the receiver is powered from the speed controller. Whilst I remembered, I dug out the programming card for the controller to set the speed controller for LiPo operation and also set the battery cut-off voltage accordingly.

The receiver was then fixed to the side of the compartment with some cable ties and all of the servo wires tidied up with cable clips, the two receiver aerials were also re-fixed in the recommended 90 degree polarisation and also secured with some clips.

The small ‘platform’ that I had the old receiver battery mounted on is an ideal place for a battery voltage alarm which is a very useful thing to have with a LiPo battery system, the audible warning is very loud and can be heard quite well even when the boat is running at speed and a vital prompt to bring the boat in for a battery swap.

With all of the wiring in place I was able to test the system for full operation and it all worked perfectly. Previously I had to remember to switch on the receiver battery supply before turning on the main power switch, now it is all powered up by the main switch alone.

As the battery/receiver compartment was already quite crowded I decided to do away with the separate receiver battery, switch and voltage meter. The receiver would now be powered by the BEC in the speed controller. The power meter was also removed as it was seldom used to log any power parameters and it just overcomplicated the wiring loom.

The first job was to modify the battery cradles and Velcro securing straps and to remove the receiver and its associated power switch and battery voltage indicator, and also the cable loom and cooling pipe support bar that would make it difficult to put the new batteries in the hull.

After removing all of the plumbing and wiring the support bar was cut away from the bulkhead with a fine tooth saw and the other end removed from the rudder servo compartment too. Both holes were cleaned up and painted with silver Hammerite to seal the plywood and then a 20mm rubber grommet fitted into each of the old holes hole to seal the compartments. I then had to use my right-angle drill attachment to get a step drill into the hull to make new holes for the wiring and plumbing. These were also painted to seal the ply.

With the support bar out of the way I could then put back all of the servo wiring to the receiver. As I had drilled the new holes through the bulkheads quite high up I was able to tuck the servo wiring up and out of the way of the new batteries, some needed extending as I had to reposition the receiver, and I also used some new silicone tubing for the cooling pipes as they were both slightly too short after re-routing them.

After some other mods to the battery support bars and some new Velcro retaining straps both of the batteries fitted nicely into the compartment with relative ease.
Easy removal of the batteries is important as I will not be charging these new packs in-situ, although I have retained the in-board charging facility.

Next up…a bit of re-wiring and motor cooling.

On the last outing of my crash tender the run time from a fully charged set of NiMh batteries was very short and I had to bring the boat in after only a few laps of the lake. I changed the batteries over to my second pair and tried for another run but the performance of the boat was similarly disappointing.

Those NiMh batteries are now about 8 years old and despite regular maintenance charges are clearly not capable of delivering the power required for the boat to perform as it has previously.

It’s clear that the batteries are in need of replacement and it is also a good opportunity to move to a better battery chemistry. The obvious choice is LiPo and so I began by finding a battery of the right voltage, capacity and most importantly, size.
The old NiMh batteries were 9.6 volts each and wired in series to give a 19.2 v supply and they were placed either side of the prop shaft to give the correct balance, however I was confident that a single LiPo would easily do the job of the two old batteries but to maintain the balance of the boat I would either need to make up a dummy battery of equivalent size and weight to maintain the equilibrium or put in two new batteries.

I decided that the simplest, although more costly, way to proceed was to have a second battery in the hull that I could change over to when required.

My research turned up a suitable battery pack made by Overlander, a 5C LiPo at 18.5 V and 5000mAh capacity, and not only was it almost a similar size it was also a very close equivalent weight to the old NiMh pack. However I would need to make some alterations to the battery compartment to accommodate the difference in height of the LiPo packs.

As one single new battery was more than adequate to run the boat it meant that I could retain the existing wiring harness without modification as I did not want to have to incorporate any kind of changeover switch to facilitate a battery change, I would simply do it as a plug swap.

I purchased the new batteries from my local model shop. Yes, I do have one nearby I’m pleased to say!
Al’s Hobbies in Volverton, Milton Keynes is quite close to my new home and it’s a delight to go there to feast on the aroma of a traditional model shop.

Older readers will know to what I am referring to!

With the batteries back in the workshop I was able to make some true comparisons between the old and the new packs to confirm their suitability.

In the pictures you can see the battery compartment with the NiMh battery supports and Velcro retaining straps that will need modification.

Also the comparative size and weight of the old and new batteries and some wiring and cooling ‘plumbing’ that will have to be removed to make way for the new battery set.

OK...time to get some tools out 😁

I’ve not posted anything on this blog for quite a while as I have since moved house from London to Buckinghamshire into a ‘new build’ house with an internal garage which I have finished converting into my new workshop. With all of the business of settling into a new house out of the way I decided that it was about time to get back to some model engineering.
First job, some much needed refurbishment of my Vintage Model Works 46” RAF Crash Rescue Tender.
I’ll be posting updates on that in a short series and I hope you will be interested in how it went……

Since completing this model have started work on a new boat and I promised those following my Crash Tender build blog that I would post an update here.

The new model is a ‘Thames River Police Launch’ constructed from a kit by Vintage Model Works.

The new blog is here:

builds/view/47891

It’s been a while since the boat had it’s maiden voyage on the lake at St. Albans and I’m pleased to report that it looks really good in the water and goes like stink if you open up the throttle.

Sadly I still don’t have any decent video of the boat yet as I can’t film and drive the thing at the same time, but I do have some static wide shots from my GoPro.

When I do the video I’ll ask a cameraman mate to do the honours, maybe I’ll put the GoPro on the bow and then the stern to get some low action shots…the storyboard is already building in my head!!

These early runs were great as they showed up some minor problems that needed attending to.
I found that it needed ballasting slightly as it was not sitting on the waterline evenly from side to side so I flattened out some old lead water pipe and cut it into small sections so that I could add ballast incrementally.
I did this in the ‘domestic test tank’ and once I was happy the lead pieces were fixed in place inside the hull with some super strong double sided tape.

The ESC needed a little programming adjustment because I had forgotten to set the low battery level point to ‘off’ as I am using NiMh batteries and not LiPo’s , that was the cause of the short initial run time on the first outing…..DOH !!

The batteries are now held in place by Velcro straps on some bearers that I added, otherwise a battery change involved cutting cable ties and replacing them at the lakeside…not very practical.
The volt/amp/watt meter is also now on a proper bracket so that the display is more readable.
I have also changed the charging connection from the nasty Tamiya connector to a nice little panel mount XT 60 connector that HobbyKing sell, it comes with a handy blanking plug that I have drilled for a retaining cord.

I have also finally got around to upgrading the firmware on my Turnigy i6 radio to the 10 channel version so that I can assign the lighting to the switches properly and have the rotation of the searchlight on one of the two rotary knobs.

I can use the old 6 channel RX in the new boat….blog coming soon.