Talk:Sd.Kfz. 7

"Hydro-pneumatic tires"?

I have never heard of any such thing as hydro-pneumatic steering tires. Most tires are pneumatic, although some can be hydraulic, i.e. filled with water to support heavy weights. If these tires are indeed some special design filled with both water and air, it ought to clearly state this to avoid confusion (and and explanation would be great; if nothing else, how they managed to use water-filled tires in Russia in winter). If not for the fact that this is a heavy vehicle and I HAVE heard of hydraulic tires on tractors, I would just assume this was a mistake, and the writer was thinking of the steering mechanism, which acts through the front wheels to steer. Those are also often hydraulic...although not hyrdo-pneumatic. Again not impossible, but strange enough it deserves explanation. The most typical thing is hydraulic steering steering via pneumatic tires. But I'm not changing anything myself, because God knows what kind of crazy engineering the Germans put into a beast like this.

64.223.167.205 (talk) 04:58, 4 January 2019 (UTC)

I'd assume the steering is hydro-pneumatic but not the tires itself. I'll try to find something in my books but don't know how far they go into details. --Denniss (talk) 10:23, 4 January 2019 (UTC)

It's possible; the Germans were great at engineering strange and unlikely things. But I've never heard of any steering system that blends pneumatic and hydraulic functions. PLain hydraulic can do anything you want as far as steering goes. Air would be ideal for braking, or for actuating gearbox clutches. Hard to imagine what use it would be in steering, except maybe for sending signals between the steering box and the clutches/brakes that run the track steering. But I would love to know about it if it was the case.

I also noticed in passing as I came that the info box says "11 passengers". I don't think this is right; this is purely OR, but the two bench seats carry 5 men each, even have clips for 5 rifles on the back of each seat ahead of the passenger, and there certainly appears to be plentiful room for three men in the front bench, including the driver. That would make 12 passengers, 13 with the driver. I notice that the text says "can carry a gun crew of 12 men": does this include the driver, or is he separate from the others, and his only job is driving? I wonder if someone didn't see the number "12" in a book and assumed it meant 12 total, when it actually meant 12 passengers and a driver, and so they transcribed that into "11 passengers and a driver" when the filled out the info box. I've seen that kind of thing happen all the time on Wiki. And it seems clear to me, 5 rifle clips per rear bench (not to mention that 6 abreast seating would be getting very unwieldy in terms of width) and the front bench is split 33/66 (1/3rd, 2/3rds), just like a modern 3-seat pickup truck cab meant to carry 3 passengers (admittedly a lot more comfortable with only two, but there appears to be ample room for both the shifters and the middle passenger's knees in this case; the SdKfz7 is a big machine, lots of spare room).

64.223.167.57 (talk) 04:25, 5 January 2019 (UTC)

I looked around a (very) little on the net, and I found a couple things. First is that the Sd.7 had two large tanks that look like air reservoirs underneath, behind the drive sprocket. I'm guessing that the system uses air brakes and/or clutches for the rear tracks, which form part of the steering system, and someone saw in a book "hydro-pneumatic steering system" (referring to both front wheels and track steering), and assumed it referred to the front wheels only. That is the most logical thing, because air brakes more more sense than air steering, and track brakes and differentials and clutches form most track steering systems of that era.

Second, I am confused on the passenger capacity. I find at least one picture of a model with SIX rifle clips per rear bench, but I suspect this ia a mistake. I find models and historical photos showing either 3 or 4 men per rear bench, usually 1 or 2 in the front. Doesn't mean it couldn't hold three, just no sense in being cramped if you don't have to. But it's hard to make sense of it; if it was 4 men per rear seat, and the other two rifle clips were for the front passenger's rifles (I don't see any in the front), that makes 11 men total, if you include the driver...but only ten rifles, so not all are "fully equipped" then. If it is 5 per rear sea, with only 1 passenger in the front, that comes to 11 men, and one driver...but why such a large seat in front, where does the spare rifle go? And it does look from photos like 5-abreast seating would be pretty crowded. But 4 abreast cannot add up; it has to be one of these (x + y equals passengers plus driver, rear benches, front bench, driver, or driver included in crew):

Four per bench, 3 in front bench

• 8 + 2 + 1 = 10+1
• 8 + 3 = 11

Four per bench, 2 in front

• 8 + 1 + 1 = 9+1
• 8 + 2 = 10
• 8 + 1 + 1 = 9 + 1

Five per bench, 3 in front

• 10 + 2 + 1 = 12 + 1
• 10 + 3 = 13
• 10 + 1 + 1 = 11 + 1
• 10 + 2 = 12

OR, lets say all the crew sit in the back, and the driver sits alone and separate in the front, you would have either 8, 10 or even 12 men in the back, plus a driver.

The only one that comes close to adding up to what this (and other) pages says is the 5 men per bench, with a single passenger in the front, and a separate driver. That comes to 12 men, and adds up to 11 passengers, one driver. Which is basically what I already said! Except I didn't believe it since the front bench seems so clearly made for 3 men. Maybe the officer, or a co-driver, or a mechanic? Anyway, if that is the case, then I'm not sure about "gun crew of 12" part. Is the driver a part of the gun crew? Is each prime mover assigned to a specific piece of artillery or AT gun? Of course none of this matters a whole lot. I'm pretty sure it generally operated with less than the maximum number of occupants, and the real maximum was however many could sit onboard without falling off (as can be seen in photos). But it'd be nice to know what tje manufacturer intended for it to hold. Any why only 5 rifle clips? Officers carry pistols instead?

64.223.167.57 (talk) 05:05, 5 January 2019 (UTC)