RattlesnakeBob Posted September 11, 2011 Share Posted September 11, 2011 (edited) I wonder if anyone has any thoughts/ideas/opinions on this...:undecided: I think I'd be right in saying that all tanks still made throughout this world have a 'standard' drive system...in that they have an engine coupled to a gearbox ... can anyone shed any light on why a diesel / electric system hasn't been tried /used?? (as in a diesel engine spinning a generator that powers electric motors to provide the drive)......... I can think of quite a few advantages... first off, that it would be a lot easier system to get the hang of driving....rather than a complicated gearbox/clutch.....most diesel electric vehicles just have a motion lever control system...forwards for forward...backwards for reverse etc.....so you could have one for each track and Bob would be yer uncle!.... ..........also.............. the more obvious advantages of , no clutch or gearbox to break down & wearout....also way simpler maintenance etc..... the only major disadvantage I can think of is perhaps the weight of an engine and a generator and the drive motors ????....... I think the US experimented with a diesel electric system around about the middle of the last war whilst they were working on the successor to the M4 Sherman but for one reason or another it never got past the prototype stage......... any ideas???????:-) Edited September 11, 2011 by RattlesnakeBob Quote Link to comment Share on other sites More sharing options...
andym Posted September 12, 2011 Share Posted September 12, 2011 There's nothing new under the sun, and the Germans have already tried most of it ... http://en.wikipedia.org/wiki/Elefant Andy Quote Link to comment Share on other sites More sharing options...
paulbrook Posted September 12, 2011 Share Posted September 12, 2011 The answer is volume, as that is the key thing for armoured vehicles You need to get the power you need to the tracks (or more properly the ground) using as little hull volume as possible, as each square cm of space has to have armour round it, and its one of those square law things where doubling the volume triples the armour needed (and hence weight, meaning more power needed and so on) The current state of technology is in favour of the mechanical drive on the critical volume equation. Its a close run thing though and there are plenty out there with things electrical on the table. Quote Link to comment Share on other sites More sharing options...
RattlesnakeBob Posted September 12, 2011 Author Share Posted September 12, 2011 The answer is volume, as that is the key thing for armoured vehicles You need to get the power you need to the tracks (or more properly the ground) using as little hull volume as possible, as each square cm of space has to have armour round it, and its one of those square law things where doubling the volume triples the armour needed (and hence weight, meaning more power needed and so on) The current state of technology is in favour of the mechanical drive on the critical volume equation. Its a close run thing though and there are plenty out there with things electrical on the table. Cheers Paul..I see and understand your point ....... Deisel/electric works well though so I guess it's a matter of time......once they can get the drive train down to a manageable size I suppose... Interestingly Caterpillar are already making a dozer with a deisel/electric drive and for years now a lot of the huge dump trucks used in opencast mining operations have been deisel/electric drive.....also not forgetting that trains have been using the system for donkies of years ......... Quote Link to comment Share on other sites More sharing options...
sirhc Posted September 12, 2011 Share Posted September 12, 2011 You also have to remember that tracked AFVs are not the same as plant and construction equipment. They are designed to travel for long distances at fairly high speed. You would need some very big motors to power a 70tonne main battle tank over a muddy field at 40mph. Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted September 12, 2011 Share Posted September 12, 2011 Cheers Paul..I see and understand your point .......Deisel/electric works well though so I guess it's a matter of time......once they can get the drive train down to a manageable size I suppose... Interestingly Caterpillar are already making a dozer with a deisel/electric drive and for years now a lot of the huge dump trucks used in opencast mining operations have been deisel/electric drive.....also not forgetting that trains have been using the system for donkies of years ......... Not forgetting Tilling Stevens who were producing petrol/electric vehicles over a century ago. Several modern cruise ships also use diesel/electric propulsion. Quote Link to comment Share on other sites More sharing options...
diamond-t-steve Posted September 12, 2011 Share Posted September 12, 2011 Then there is diesel / hydraulic just to add to the mix..:cool2: Quote Link to comment Share on other sites More sharing options...
andym Posted September 12, 2011 Share Posted September 12, 2011 Not forgetting Tilling Stevens who were producing petrol/electric vehicles over a century ago. Several modern cruise ships also use diesel/electric propulsion. Porsche was at it back in 1901! It's interesting to see what has happened in warships as they share some of the considerations of AFVs in terms of power density. Most RN vessels are now electrically propelled, mainly because it allows you to run small fuel-efficient prime movers at low speed and only fire up the bigger ones when you need the power for high speed transits. The other factor is the high ratio of hotel load to propulsion load, something also common to cruise ships. For an AFV this only really makes sense if you've got a high electrical load for weapons (rail gun) or armour (electric armour). Andy Quote Link to comment Share on other sites More sharing options...
RattlesnakeBob Posted September 12, 2011 Author Share Posted September 12, 2011 (edited) You also have to remember that tracked AFVs are not the same as plant and construction equipment. They are designed to travel for long distances at fairly high speed. You would need some very big motors to power a 70tonne main battle tank over a muddy field at 40mph. .....yep see your point too:-) .....but.... an opencast / quarry type dump truck, when loaded, can weigh in at way over a hundred tonnes and sometimes a lot more.... and they'll shift along at 30+ mph so????......:undecided:... I guess a diesel / hydraulic type drive (if used for higher speed uses such as a tank)... would need huge oil coolers ?????..perhaps thats why they're not used? all interesting thoughts and opinions though ..thanks ! and ..... I may recall this wrongly ...but...I think one of the main reasons that porsche dropped the idea of a diesel / electric drive system for the Elephant and Maus armoured vehicles was due to the the chronic shortage of copper nescessary for the drive motors in Germany at that time of the war rather than that the system couldn't be perfected??? Edited September 12, 2011 by RattlesnakeBob Quote Link to comment Share on other sites More sharing options...
Scammell4199 Posted September 12, 2011 Share Posted September 12, 2011 I would have thought there is an energy loss consideration with any fuel/electric or fuel/hydraulic system over a conventional fuel/mechanical transmission. Every time you convert energies there are losses, possibly small by comparison. A conventional system converts the chemical energy in fuel into mechanical energy, where as an electric drive system converts the chemical energy into mechanical energy, then into electrical energy and then back into mechanical energy. In converting to electrical energy there are heat and light energy losses (as with the IC engine) but it seems an unnecessary step when you're ultimatly converting back to mechanical energy. Where electric drives are used there are other considerations, some of which have already been mentioned here, which make it worthwhile. Richard Quote Link to comment Share on other sites More sharing options...
andym Posted September 12, 2011 Share Posted September 12, 2011 I may recall this wrongly ...but...I think one of the main reasons that porsche dropped the idea of a diesel / electric drive system for the Elephant and Maus armoured vehicles was due to the the chronic shortage of copper nescessary for the drive motors in Germany at that time of the war rather than that the system couldn't be perfected??? I think one of the problems at the time would have been one of control. It's only with the advent of modern power electronics that most of these systems have really become viable. Andy Quote Link to comment Share on other sites More sharing options...
paulbrook Posted September 12, 2011 Share Posted September 12, 2011 Porsche was at it back in 1901! It's interesting to see what has happened in warships as they share some of the considerations of AFVs in terms of power density. Most RN vessels are now electrically propelled, mainly because it allows you to run small fuel-efficient prime movers at low speed and only fire up the bigger ones when you need the power for high speed transits. The other factor is the high ratio of hotel load to propulsion load, something also common to cruise ships. For an AFV this only really makes sense if you've got a high electrical load for weapons (rail gun) or armour (electric armour). Andy Having spent time in both armour and HM war canoes I can say for sure that the former do not have karaoke machines in the wardroom needing power... As I said previously it the volume that counts (that's volume as in dimensions not loudness of the karaoke) Quote Link to comment Share on other sites More sharing options...
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