O.K, in regards to steering/ turning... How do those front WHEELS on a half track work??? Surely the larger surface area of the tracks would render the front wheels ineffective. Even allowing for the weight of the engine over the front axle, the weight of the rear tracks and suspension would cancel out any advantage. The only thing i can think of is by turning the steering wheel it adjusted the amount of drive to either track, like a bulldozer... Or am i just plain way off??
That is pretty close to how they worked (I think), when you turned the steering wheel (at least on the American model), that in turn first activated a "clutch" which removed drive power to the track on that side, and turning and holding it against the lock applied a brake to the track drive. At least that is what I have gleaned from a couple of short articles on them. I'll look around and see if the system is better explained elsewhere. PS. I like your use of the rotary engine "power rotor" as an avatar! I owned three Mazda rotaries back in the seventies. One R-100 (first model in the US), a Rotary pickup, and lastly a little beaut called the RX-2 which I really hated to trade off. It was the best of those I owned.
Most all German halftracks, (perhaps more accurately 'semi-tracks') did not have any complex steering arrangement, as such things as sophisticated tank style transmissions and track/power adjustability would negate the one real benefit of semi-tracks - cost. They only applied a simple brake steer to the tracks at full lock, up until that point they were indeed steered solely by the wheels. When you watch survivors maneuver you can see that they are not exactly agile, but the system at least works - rubbish turning circle but 'adequate', and adequate was the best compromise if one was understandably unwilling to go the whole hog & install full-tracks that really could keep up with the armour. Seem to recall that the US halftracks didn't even have the simple track-brake-steering and the tracks just push forward all the time (disconnected from books and a bit hammered at the mo so don't quote me ). When you see them in the flesh they're apparently a lot more agile than German types, but the tracks have a much smaller footprint so presumably the front wheels can dig in more when steering. I like halftracks, but we have to remember there are some good reasons the system finds no favour in postwar thinking outside of the odd Landrover Centaur and other wacky (but pleasing) projects. None of which reached wider military service. ~A
Here is a photo of the M3 American half-track with it's running gear exposed, if you look to the right of the right-hand driving axle, outboard of the differential and the frame, the large drum brake can be seen. The one for the left-hand track is hidden in the shadow, but it is there. Those drum brakes are hydrolically operated, and since the track is driven through a differential, when that side is "stopped", it will free wheel, and the other side will get all the power, just like when you go around a corner with a rear wheel drive car or truck, the inside wheel free wheels temporarialy and the outboard wheel receives all the power. A hinderance on ice with drive wheels if one is on ice and the other is on solid ground. The one on ice will spin impotently, and the one with traction will do nothing if you don't have a limted slip differential (positraction).
Like I said Clint, don't quote me . I share Krazy's fascination with the things though, ever since a lady mate that came to Beltring a few years ago asked "Why halftracks" when watching the Wheatcroft Famo mount a bank (front wheels must have been 20 feet in the air!) and I had no real answer at the time. After a few years scratching my head cost does indeed seem to have been the primary reasoning.
Thanks for both of your input... It seems i have found my answer, thanks for the great photo too... 1000 words. And Clint, I'm hugely jealous of your previous cars. We're lucky to have a HUGE rotary culture down here, and RX2,3 and 4's are very popular, but r100's are considered rare treats, and REPU's mystical (think theirs only 2 in country..) Currently building my third mazda (FD RX7)and a rotary Vauxhall viva
I'll call Old Hickory first chance I get. He spent enough time in one and working on it. He should have some good insight on the vehicle.
Also a difference between American and German Halftracks is that on the American version the front wheels were 'driven' whereas the German halftrack wheels were not. Don't know if that made any difference.
In talking with Old Hickory, he mentioned the front wheel drive being a good thing. He said that it made it easy to do track repair, as the truck could move well without any tracks on at all. It couldn't go real fast, but the vehicle could go a good distance on roads and flat ground on just the track wheels.
I talked to Old Hickory tonight. He described the M3 Halftrack as more or less a truck with tracks in the rear instead of wheels. The tracks were driven by a drive shaft from the transmission to the rear differential. When the truck turned, the differential sent less power to the inside track and more to the outside. He said the halftrack would turn surprisingly sharp, as good or better than a truck. He said that it did not plow the front tires, they were pulling too. He really liked the halftrack and said that they were very dependable and did not break down or throw tracks much at all. The engine was a 6 cylinder gasoline engine made by White and the only problem they had with it was when an enexperienced and frightened driver over-revved the engine, as in fleeing gunfire. If he way over-revved it, could strip out the distributor gears. It was fairly easy to fix, but could be fatal if it happened at the wrong time. I think I mentioned before, the tracks were easy to put on and lasted a long time. He said that unless they were on paved roads, the track would rarely need changing. Changing tracks did not require a jack, either. They would just lay the track on in front of the bogies and use the front wheel drive to pull the vehicle up on the track. Then they would connect and adjust the track and was ready to go in less than 10 minutes. He didn't like the M-8 armored car. He said the engine wasn't nearly as good as the engine in the halftrack. He said the armored car would have been a much better vehicle if it had had the White engine that was in the halftrack. He said the could not keep the valves adjusted, no matter what they did. He said they had 6 weasels when the went to the continent and after a few months, they were all gone. He did not like them, as they threw tracks way too much if the machine was turned too sharp. It was the inside track and the vehicle required a jack to retrack, which took a long time to accomplish.
Thanks for going the extra mile Slipdigit, great info on the M3! I wonder what your take is on those giant drum brakes on the end of the diff, in brndirt1's photo... Possibly to assist in turning e.g. offroader style. If they are hydraulically operated it's sure to be more than just a handbrake Maybe one day I'll be lucky enough to see one in action at Warbirds over Wanaka...
