fv1609

Introducing more inductance than resistance with the new fancy coil & its ballast resistor will bring about a disadvantageous time contstant which will reduce HT output at higher speeds. We have now an arrangement that undoes some of the advatages that were so carefully designed into the system in the first place. Looking at the DC activity of the new system we have a new fancy coil with a resistance of 3.3 ohms with a ballast resistance of only 1.82 ohms. This gives a total resistance of 5.12 ohms, when supplied with 24 volts by Ohms Law it means a current of 4.7 amps will flow through the coil. The power dissipated (heat) in this coil is 73 watts. This a cautious calculation, because when the system is in normal running & charging the voltage supplied will not be be 24 volts but 28.5 volts. Working out the power dissipated it comes to 102 watts. This is a lot of heat to dissipate on a very hot engine. Applying the same calculations to the original RR installation at 24 volts the power dissipated in the coil is 38 watts & when on 28.5 volts the power dissipated rises to 53.6 watts. So we are introducing a system that now has a coil in it that is creating double the amount of heat (102 watts) compared with the original coil that dissipated 53.6 watts. I have no doubt that "it works" in delivering HT, but no wonder it gets hot! I am intrigued as to the design working voltage of the new fancy coil. In the proposed set up with the ballast resistor supplied the coil will be working off 18 volts. I was unaware that coils are made for a strange voltage like this. Ignoring the inductance/resistance time contstant issue for screened miltary systems, my understanding is that coils for use with a ballast resistance were purely for an "easy start" voltage. A coil might be designed to run off say 10 volts with a ballast resistance in series the system would normally be supplied with 12 volts. At start up the starter motor may cause the nominal voltage to drop to 10 volts. The starter switch would short out the ballast resistance so there is no detrimental drop in HT output when it is most needed. The RR system applies the full 24 volts to the coil bypassing the ballast resistances during the start up phase, but allow the resistances back into circuit once started. So we need to know the design working voltage of the new fancy coil. If it is not designed to work on 18 volts & is in fact a 12 volt ( or I hope not a 10 volt) coil why doesn't the ballast resistance match the coil resistance? Because not only is the time constant disfigured from the original design but the fancy coil is dissipating double the heat of the earlier coil. Ballast resitances in civilian ignition systems are for improved cold starting & although this feature is incorporated in the RR system, the important issue for a screened HT system is the improved time constant to allow the magnetic field in the coil to collapse & deliver the maximum spark. As yet I can see not benefit in providing a poorer time constant & coil that now gets twice as hot. Having said all that, the electronic ignition module itself is a superb device in terms of ingenuity & its contstruction. I have bought two such modules & am very pleased. I would strongly advise others with B Series engines to take advatage of the module, which although is expensive will prove to be a very worthwhile modification. But on the present evidence a new coil & its ballast resistance seems a mod too far.

Mark yes I had two of those, one nearly caught me out as it was "re:Shorland."

The pages below come from the book of 1956 FVRDE exhibition. FV604 is allocated to ACVs there were at least 5 versions of FV604(A) based on Saracen Mk 1 & Mk 2. FV604(B) & FV604(D) was based on Saracen Mk 5. Not to be confused with FV610.

Andrew thats good news. I have to admit that I'm still intrigued by the design voltage intended for this coil & that it will be getting much more than 12v. The time constant will be higher than in the original RR setup as that is dependant on the inductance divided by resistance. So although this coil may be drawing more current to create a greater magnetic field, if the time constant has increased, at the highest speeds the magnetic field would not so readily collapse as in the RR design with a ballast resistor equal to the resistance of the coil.

CM in VAOS or DMC use is for cold climate clothing:???

Yes stuff does shift. I prefer putting stuff on here rather than the other military site, which may possibly have a wider viewing public. Unfortunately that wider viewing public includes some tricksters, mischief makers & dreamers. For every advert I have placed there the genuine & serious response level has been disappointingly low. On here although it is a little bit more of a closed community, in that you have to be registered to send the seller a PM, the quality of response to an advert is much higher. Just a suggestion I think if you are going to sell stuff or pursue queries about equipment some photos will trigger responses more readily.

The one I got from Jack has been requisitioned by my wife for her horsebox. She is none too interested in seeing what is behind her, the camera is set up to watch what the horse is doing in transit. So I have had to buy a system for myself. I have fitted it to the Shorland. It is very dark inside the cab & the screen shows up well. The problem is that a vehicle that is 10ft behind looks to be about 30ft behind. When it is 30ft behind is is a very tiny image that I can only see with reading glasses. I find it quite worrying that these very near vehicles appear much further away than they really are. Do others get this problem or is it just the price I have to pay for having a relatively good "fish eye" coverage? It is one of these: http://cgi.ebay.co.uk/Rear-Night-View-Parking-Reversing-Mini-Colour-Camera-N-/370257840052?cmd=ViewItem&pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item56351647b4

A lot more stuff to go up yet!

Andrew, your circuit looks fine. Seems odd that the ballast resistance is now about half that of the coil. The advantage of the old system was that by loading the circuit with a resistance equal to that of the coil it offset some of the effect on the inductance of the coil. In that 12v plus equal ballast resistance gives more effective HT output than a 24v coil alone. Some of that advantage has been lost now that the resistance added is only half the resistance of the coil. Although the coil now will be receiving not 12v but more like 18v. So it will be drawing more current so maybe that wil be sufficient to compensate?

Andrew, oh well yes I see why there were problems with the ballast resistors. Certainly wise to side step that lot & keeping the new resistor away from the wiring in there, so that the BST wiring doesn't short the new resistor out during start up. A new junction box would be worth looking out for if at some stage you decide the fancy coil is more trouble than it is worth. Looks like it's been letting the moisture in for some considerable time. Were the lid screws not fully tightened, as the rubber gasket looks quite stained? So is the new coil 1.82 ohms as well?

Updates for Series 5 APC & APV. http://www.shorlandsite.com/CarSeries5.htm http://www.shorlandsite.com/VehicleS55.htm

Out for a drive round the fields.

http://www.warandpeaceshow.co.uk/Show-Information/2010-Show/Trophy-History.html

Andrew, well the resistor looks fairly robust. Although I said it must dissipate 144 watts, in reality it will be less than that as the current is only flowing when the points are closed of course. I would be interested to know its actual resistance. I assume you have removed the lead that shorts out the ballast resistor when the starter motor runs? Otherwise that would be quite a current for the new low resistance coil to handle. For my module supply I used similar looking screened cable from some other application.

Many thanks for your comments. I still haven't got used to the idea of what has happened. One particular regret was that my Pig was off the road at the time of Dale's funeral. Had it been running we would have liked to have used it for his final journey, something that he would have approved of. The irony being that some weeks earlier he was offering to come down & give me a hand with it. A memorial trophy has been set up to be awarded annually at W&P. This has a number of novel concepts. More details later.

Many will have noticed that I have been selling a number vehicles & various MV items. Those who are in the MVT will have seen in the latest Windscreen the reason for this. But for those who don't have access to the magazine, the explanation is here. Dale Prior 1949-2010 I am very sad to report the unexpected death of Dale Prior from Reading on 14th March 2010, a valued friend and Humber enthusiast. Dale was born on 1st October 1949 and as a boy first made contact with things green and mechanical when he was given a Jeep in the form of a pedal-car. His interest in military vehicles blossomed as a lad when in 1956 he watched convoys of vehicles bound for the Suez Canal heading along the A4 outside his house in Maidenhead. To see in real life the things that many of us saw only as Dinky toys created a lasting impression on this young lad. Young lads grow up and Dale served his apprenticeship as a vehicle mechanic for Fords in Maidenhead and then moved onto Citroen cars. But his interests were not sustained by domestic cars; his instincts led him to bigger things. He took on a job as the vehicle mechanic at a local gravel pit. This was a stimulating challenge not just in the range of vehicles and equipment to keep running but it was a test of his ingenuity to source components not readily available. Dale took out his HGV licence and derived great satisfaction in driving much of the heavy stuff that he had learnt to maintain. He enjoyed ten happy years on the road and I imagine they were happy years for the vehicles as well, given that they now had a driver who knew how to treat a vehicle with respect! For a while Dale relinquished the wheel and turned his hand again to repairing HGVs. The frustration of regularly repairing faults that could have often been avoided by greater respect for things automotive became too much and Dale took up his HGV driving again until his untimely death. But when did the real military vehicles come in? Not until he got married! A week before his marriage to Alison in 1973 she mentioned someone at her work was emigrating and was looking to dispose of a Jeep; well it was actually an Austin Champ just like the Dinky toy owned by the boy from Maidenhead. So that was the start, along the way other vehicles gradually accumulated culminating with three Humber Pigs, a Humber Malkara Test Truck, a Humber Wireless Light, a Humber GS, two 2A Land Rovers FFR, two Lightweight Land Rovers, a Defender 110, a V8 Pilot that belonged to his father and of course the faithful Champ. Although Dale along with his son Ashley would regularly attend shows it was never with any of his vehicles. Attending shows was too see other people’s vehicles and meet their owners but above all hunt for those elusive spares to keep his vehicles running. In fact we would often joke that our vehicles would outlast us both and we had a sort of duty to ensure that they did. To this end we spent many happy sunny days picking over Pigs in a scrap yard on Salisbury Plain. Dale was a modest and unassuming man and on a first meeting one might not gauge the extent of his collection. His modesty was such that he shied away from his name being quoted in print and to get a photograph of him was something of a challenge. But here is a picture of Dale with his mind on other things as he oversaw the removal of a Pig engine and gearbox, saved from becoming part of a range target. It had been an ambition of mine to get Dale to at least one show with one of his Humbers. But I know full well he derived just as much satisfaction visiting his vehicles, servicing them and just listening to the smooth purr of a B60 engine. Despite enjoying good health throughout his life, it is extraordinarily difficult to grasp that I have suddenly and inexplicably lost a very good friend. Clive Elliott

Many thanks to the organisers. It's so easy to forget to say so at the time. The return journey was memorable. The reversing camera on the Pig took it upon itself to go into direct image rather than mirror image. This gave the impression that the car overtaking me on my right was doing so on the left. Not so good when I started reversing the Pig having overshot my turning!

Some slight discrepencies looking at RAOC Statistics Pam. No.5. Weights & Measurements of A, B & C Vehicles.

Further confirmation in Data Book of War Dept GS "B" Vehicles, 57/Vehicles A/4510. If anyone needs it I have similar pages for water, dry air charging & welding variants.

This is from the UHB. The EMERs & FVDE (not a typo, predates FVRDE) Design Spec gives no more detail.

Mark, there were a series of Military Training Pamphlets produced in WW2 many of which covered Camouflage. Camo nets are covered in No. 26, 46 Parts 1, 2, 4 & 6. There is also some coverage in Concealment in the Field 1957 WO Code No. 9459

Kandahar (Barracks!)

Hello Ginge. A few years since I've been inside the camp. But here I am when I had more hair & when I had the Hornet. It was made very clear there were to be no oil drips!