"Need feedback and advice on tank steering/maneuverability" Topic

Most tanks games I've seen maneuver tanks pretty much the same way. I feel there is a difference between speed and maneuverability. Not all tanks maneuver equally because they use different methods for turning. It appears one using regenerative/differential steering do no slow down any appreciable amount (unless using their brakes) while many games penalize all tanks for turning. Pivoting in place with tracks moving in opposite directions (double differential neutral steering) is much different than locking one track side and slewing the tank around with the other (clutch brake). Both seem to have their drawbacks when used on poor terrain. Controlled differentials cannot perform a pivot and need to maneuver by backing and moving forward a number of times to pivot their hull. Each type seems to have advantages and disadvantages which is what we want to model in a game.

Here are the major types used in WWII:
PDF link

My understanding of these:
Clutch Brake: Turning by braking only, no neutral steering, slows down while turning. Can be dangerous braking at high speed. Used by Russians and early German tanks and assault guns.
German Double Differential: Each gear has a separate turning radius (brake turning for emergency only), can neutral steer, does not slow down while turning (unless using brakes). Used on Tiger (double radius) and Panther (single radius). The "steering wheel" on the Tiger changes steering gears enabling a change in turning radius based on what gear the tank is in and does not operate like a car.
Controlled Differential: Only one turn radius but can increase radius by braking (can skid turn on hard flat surfaces), no neutral steering, does not slow down while turning unless braking. Used by Sherman and other US tanks. Some references state the minimum turning radius for a Sherman is 50-70 feet which would make it hard to maneuver in tight areas on poor ground.

Here's what I'm looking for:
Is my info and understanding of the different steering types correct?
Any additional info of personal experiences?

For game purposes I'm looking at is using a turning radius play aid to maneuver tanks since most of the info is based on turning radius at different speeds/gears. I have turn radius info for most tanks so it should be accurate. It looks like tanks that use braking for turns will slow down and locking one side and slewing and neutral turning have greater chances of throwing a track or bogging down. I'm not trying to design a game called "Tank Driver" but want to know the details before we start abstracting and changing rules. Is there anyone out there using turning radius play aids for moving tanks? I've watched quite a few videos of tank movement and seem to be able to spot the differences.

Any opinions or help appreciated. Thanks.

Wolfhag

I think that most games groundscales aren't fine enough for that to matter.

Even at 1:300 groundscale (12"=100yds), unless you are using 6mm tanks the length of the tank is greater than your turning radius!

One potentially significant tactical effect is that a vehicle capable of a neutral turn (with a Merrit-Brown or similar gearbox) can pivot on the spot to crush a trench.

It seems to me fair enough to penalise clutch-and-brake systems more for turns than the more advanced forms of steering if you are devising a fine-grained game, but this would also suggest needing to take into consideration ground pressure and, a topic of great concern in British post-war research, the ride quality given by the suspension. Ride quality can be quite a stern limit on mobility across rough terrain.

All the best,

John.

Lion in the Stars: They are tweaking the old Tractics rules (don't ask me why)using 1" = 25m and about 30 second turns. Too many players were rotating their tanks like tops and moving them through the hedgerows like sports cars. Right now movement is done with speed deduction for any turning. From watching videos I can't see much deceleration in a turn when going less than 10mph, especially when neither track is stopped by braking.

What we are hoping to do is give a tank a rating based on its steering type. From the info I found tanks would not normally do a skid turn (lock one side) going more than 10-12mph. In videos I've seen a Panther take 3 seconds to skid turn 90 degrees on a hard surface. Probably twice as long on softer ground. Any tanks performing skid turns would chance a bog or break down (depending on the ground) while moving in your normal turning arc probably would not. We think the tanks are too maneuverable right now so we are trying to get some other ideas.

I've made turn movement radius disks and it was a little surprising and could be workable with 1/285 scale tanks. A Tiger I moving at 13mph has a 50m (2")turning radius and is able to get around it about 190 degrees in one turn of moving without using brakes to tighten the turn if my math is right. It could spend time making a skid turn and then move out too. A little complicated but we'll see where it takes us and what the guys want to do.

Wolfhag

Again, as with your other Tank query … I think you are over thinking the rules a bit … but do what works for you …

As an ex-M60 driver, I have to agree with Legion 4; I think you're waaaay over thinking the issue. And at 1"=25m, most tanks should be able to complete a full 180 degrees (one way or another) well inside an inch. (And where in the world did you get those stats on the Sherman, Panther and Tiger? I have info that completely runs counter to that… Including a video of the French Armor Museum's Panther doing a 90 degree skid turn (in segments) in about along as it takes to say it…)

If you must get this specific; I'd drop any idea of a "turn radius gauge" (because its unrealistic, would be a bear to verify the info, and the "radius" would vary according to speed, ground and (yes) training of the driver) and just go with a speed discount based on speed, conditions and the tank's ease of turning (and that last is going to be nigh impossible to quantify).

coastal2:
I think I saw the same video about the Panther doing a 90 degree skid turn in 3 seconds at almost a stop as I mentioned in an above post. It almost seems all tanks are equal up to 10-15mph in their ability to skid turn using brakes but I'm not positive. From the info I've found tanks don't lock one track to skid turn going over 12-15mph as it can stall the engine or throw a track but most could "blip" the brakes to alter the radius at a speed penalty which may not be worth considering. German Tiger and Panther manuals said to use the brake to steer only in emergencies which means it could have been used quite often, I can't confirm or deny, or the ramifications if any. If anyone knows of WWII tanks that completely locked up one track with their brake to perform a skid turn greater than 45 degrees at 15+mph on sandy or soft soil as SOP I'd like to know. Any tank can "blip" the brake to change direction but using a differential you can get a radius (without significant slowing down) depending on the gear/speed without having to use the brake – but can if you want but it will slow you down. Big difference. Clutch Brake systems can only use brakes as they have no steering differential.

I agree that any tank that can lock one track can turn in 180 degrees in place if stopped or going very slow. The question is at what price if being done on sandy/muddy/poor ground? Some tanks (Tiger and Panther) can "neutral steer" without locking one track with both moving in opposite directions. What's the downside and advantage of the two? I've come across AAR's from Sherman drivers that stated they could not neutral steer or pivot/skid turn in place when they should be able to lock a track and skid turn (but not neutral steer). In "Panzers at War" by Michael Green page 87-88 he discusses steering of Sherman and Panther and stated it was impossible (which means never) for a Sherman (controlled differential)to pivot turn/neutral steer like a Panther. I've read AAR's that stated the same thing. Surprised the hell out of me. This should explain why one tank is more "maneuverable" than another. As always you run across conflicting references.

References for fixed turning radius based on gear/speed are in "Tiger I" by Jentz and Doyle and numerous other technical references. Do a Google search for "turning radius" and the tank type and you'll see many references and find the different steering mechanisms. It didn't make any sense to me until I read about the different types of steering mechanisms in the link I posted above. Yes, radius depends on gear selected (using a differential which slows down inside track and speeds up outside track) and therefor speed. WWII tanks all had drum type brakes but using them for steering was difficult, inefficient and slowed the tanks speed. Driving any modern tank, including an M-60, is much different than a WWII tank from what I've found.

Right now the movement we are using for tanks is to allow them to move, pivot/turn, move, pivot/turn, etc in any combination with unlimited turning ability but with a speed penalty. The speed penalty can be over 50% of the speed (even making a few small direction changes) which I feel is unrealistic. Using turn radius gauge seems to make turning/speed realistic for Controlled differential (Tigers, Panthers and Shermans) and giving a slight speed penalty for "blipping the brakes" to alter the radius (and lose speed) could be the answer. Clutch & Brake (Russians and early Germans) steering would not use a turning radius as they only use braking to turn and would always lose speed much like the current system we use. To do this right I need to understand the differences in steering types and how they were used in reality before making the needed abstractions and playability adjustments. Driver training is another variable but not important to understand the technical aspects and limitations/differences of turning. That's where I need some help. If it's confusing to you it was to me too. I was hoping my first post would help clarify the differences.

Thanks,
Wolfhag

"Driver training is another variable but not important to understand the technical aspects and limitations/differences of turning."

Dead wrong. A bad driver can manage to throw a track on a concrete pad at under 10mph (I've seen it…). A good one can do things that the tech manual says is impossible.

Frankly, I think you have fundamentally misunderstood how track vehicles actually move and behave in a tactical situation over open ground.

Wolfhag,

As someone who has spent a large part of his adult life in and around things with tracks, I have to agree with coastal2 about the importance of a good driver. Given the level of detail that you seem to be going in to (and I have to wonder why you are doing so), to dismiss driver training and ability as "not important" seems bizarre.

What is the time length of a move in your rules?

Jurgen

The problem with trying to do a very detailed design ( of anything ) is that you can quickly get bogged down in detail and miss the big picture. The relative importance of details can be quite difficult to get right.
I see this all the time in my profession.

The thing this messing about with turn radius stuff rather overlooks is how ww2 tanks would usually move in or around combat.
They had no effective stabilisation, crew comfort was often down the bottom of design considerations and mechanically they were way less reliable than modern vehicles.
They stopped to shoot.

A net result of this and concern about meeting undetected enemy meant they mostly crept about or sat there giving support to other tanks rather than racing along.
There are exceptions to this but they can be glossed over or you can paper over the issue with shoot or move.

If you consider the Churchill then you might think this looks pretty slow on paper. As it turned out this wasn't an issue in real combat.

And.
As others have pointed out, crew quality has a much more significant effect than the stats of their ride.
Panthers might look like they ought to wipe the floor with regular 75mm armed shermans. Put poor quality german crews in those panthers and high quality US crews in the shermans and the reverse happened.

Detail is a tricky thing.
People often assume more detail means more realistic rules.
Very difficult to do it right and by the time you do so you are likely to notice that many things have negligible effect.
I would suggest turning circle of a tank is in that category.

I was going to ask how often WW2 tanks were traveling more than ~12mph in combat!

Lion- You're dead on. A M4's book top speed is generally pegged at around 25mph. Which it can do on a paved road. Once you go cross country, you can cut that by half (at least). Sure, a tank can get up to speed on open ground, but the crew might not make it what with being pinballed around the interior (and believe me, the inside of a tank is nothing but hard, sharp and nasty. Kinda like a submarine, I imagine…). I'm reminded of a incident at a British show where, IIRC, a Chieftain did a fast run (20mph? or less) on an open, leveled field. The medics had to remove the driver (he'd been damn near knocked out. And the rest of the crew was in barely better shape). Even more modern tanks (M60, Chieftain, Leo 1) could only do a little better cross country. It wasn't until the latest generation (M1, Leo 2, Challenger) with some truly trick suspension systems that you saw a dramatic increase in cross country speed.

One more thing: if you're accompanying infantry on the ground (like in WWII), it really doesn't make much sense to go fast (haven't met a grunt yet who could do better than 3mph!).

First I really appreciate all of the advice, experiences and comments. I've ridden on the back of an M-48 but never driven one. I'm a grunt. Looks like I need to make some clarifications.

Coastal2: I'm not discounting driver expertise (that would be bizarre) or how tanks are moved tactically over different ground (that would be ridiculous). Right now I'm interested in the "mechanical differences" in "clutch and brake" and "controlled differential" steering drive types as in the link in my first post. I didn't make this stuff up. Modern tanks do not use a clutch brake or controlled differential systems like WWII tanks. It's completely different. We'll work on driver expertise and capabilities, etc after we decide what advantages and disadvantages the different steering drive types have, if any, if it's worth considering. In my previous posts consider all things, driver, ground conditions and tactical applications being equal.

The time length of a turn we want to use is 20 seconds. From videos I've watched of WWII tanks using either steering type seems to turn about 20-30 degrees/second on firm flat ground. That surprised me but I doubt if they could do it on soft ground and maybe not even attempt to try.

Just to clarify, I'm trying to get an idea on the of the mechanical differences between the steering types of WWII tanks as stated in the link in my first post and then if they can give a driver any tactical advantage over the other. It was confusing to me and I spent a few hours researching and trying to understand it. I realize a poor/untrained tanks driver could screw up anything but in the technical paper on the link it does not consider drivers expertise but we will later.

So far my conclusion is with all things being equal that most WWII (disregard post WWII) tanks with clutch and brake or controlled differential steering systems stopped or traveling up to 12mph are pretty much equal in their ability to perform a skid turn using their brakes. Maybe that does not surprise anyone. Videos of the two types moving 10-12mph seem to bear this out too. Over 12mph the differences in steering drive type seem to come into play.

Thanks,
Wolfhag

"I was going to ask how often WW2 tanks were traveling more than ~12mph in combat!"

About as often as dodgem style tank ramming.
It did happen, but it's not something to build into a rule set.

There you are racing about at a glorious 16mph ( you're lucky and the going is just right ).
Inbetween puking up over the side of your turret you spot an enemy tank.
It has a glowing neon sign above it.
That's how you spotted it.

OMG!
"Target armour. 300 yards, 2 O'clock"
Your driver slams the anchors on.
The crew "pinball" a bit more.
Your ride rocks wildly.
Suddenly there's a blinding light and you're lying on the ground next to your tank.

The tank that fired first usually won in ww2.
You creep about, you get a chance of seeing the enemy and you can stop and shoot quicker. And of course ragging your gunner and loader around in a bouncing turret is not conducive to good shootin.

So far my conclusion is with all things being equal that most WWII (disregard post WWII) tanks with clutch and brake or controlled differential steering systems stopped or traveling up to 12mph are pretty much equal in their ability to perform a skid turn using their brakes. Maybe that does not surprise anyone. Videos of the two types moving 10-12mph seem to bear this out too. Over 12mph the differences in steering drive type seem to come into play.

That's what the professionals seem to think. A difference without being tactically significant.

And since cross country tactical speed is in the 12mph range, then any differences in the steering system would be moot.

When modelling anything (which is what wargames rules should do), it is useful to include only that which is relevant; I am far from convinced that differences in the steering system have enough relevance to be included.

Jurgen

Ditto,
I've come across the same thing with the Sherman although I don't know why it could not lock one track. I know some of the people on this post think I'm a little whacko but I'm trying to get info for a guy in our group who is tweaking the "Tractics" rules and wants to simulate tank shootouts so ability to pivot/turn in place (or not) could be important as maneuverability is a little different than speed. Not exactly my cup of tea but I told him I'd help out. I have an e-mail inquiry into the Littlefield Tank Museum to get some feedback from their technicians/drivers. I'll be visiting there in April.

I concur with the 10-12mph limit for most driving. It seems to be a safe speed to avoid obstacles and still be maneuverable.

Thanks,
Wolfhag

It's not that the M4 couldn't lock one track to make a skid turn/pivot – in absolute terms it could. However, in practical terms it could not. Explanation here link

So unless someone claims to have Conan for a driver it ain't happenin'. If it is happenin' please explain how he fits through the hatch.

cheers

It's not that the M4 couldn't lock one track to make a skid turn/pivot – in absolute terms it could. However, in practical terms it could not. Explanation here link

Ah, unboosted brakes, the bane of many a driver. I hate unboosted brakes, but I can step on them hard enough to stop. You'd want a big country boy driving.

I hate unboosted brakes, but I can step on them hard enough to stop.

No doubt you can. But in the M4 the only foot pedal the driver has is the clutch. All brake inputs are via the steering levers. How many one arm pull ups can you do? You are after all trying to stop a 30+ ton vehicle.

cheers

Its interesting that the much later M72 LAW (modern Disposable anti tank weapon) is calibrated for a max speed of 12mph as this was as fast as you would expect to see on a battlefield. Thus simple re-enfocement of what has been said. We do allow for WWII a very fast move along roads with not much bend on them. However as said at that speed you are easy to see and hit. It is usefull when re-deploying when moving from one stop line to another out of sight. We also allow a faster speed when moving between pre-set "hide positions" this was already a tactic in WWII. Thats not so much about steering as the drive being clear where he is going. Its significantly slower than road speed. Again nobody is doing anyting usefull while moving at even this increased speed. It should be rememberd that tanks take time to accelerate as there horsepower per ton is not that big.

Hey guys thanks for the feedback and advice. I have not heard back from Littlefield yet. I think having most tanks being of equal maneuverability up to 12-15mph is accurate and playable. That surprised me. The exceptions would be pivoting in place and maneuvering at higher speeds.

UshCha: I've fired the M72 LAW a number of times and remember the speed increments.

I'll get my writeup to our Tractics Guru and see what he wants to do. It's been a good learning experience for me.

Wolfhag

I did a tour of the Littlefield Armor collection. Pretty amazing stuff. If you are in Northern California you should try to book a tour ASAP as they won't be around after July.

I asked one of the docents who has also driven many of the tanks about Sherman tank maneuverability, he also wrote a book on them. He said the Sherman cannot lock one track and pivot/slew the other side around like most tanks. This also goes with numerous personal accounts of Sherman crewman in the book "US vs German Equipment" by Merriam Press by General White. It could make a difference in 1:1 tank games tanks games with a high level of detail. The Sherman needed to back up and go forward like a car making a 3 point turn to pivot it's hull.

They have the only operational Panther tank outside of Europe and he said the Panther has a single turning radius depending on the gear it is in. At higher speeds using the brakes to turn could cause damage to them but they could use them if they wanted. He said that all tanks were pretty much the same in maneuverability if they were on solid ground at up to 6-10 mph. He also said high speed turns with any tank could be dangerous. When tank brakes overheat they stop working just like in a car and most overheated easily because if the immense stress put on them.

Wolfhag

in the M4 the only foot pedal the driver has is the clutch. All brake inputs are via the steering levers. How many one arm pull ups can you do? You are after all trying to stop a 30+ ton vehicle.

Not being a tank driver, can the driver lean and use his body weight against one lever?

Translation: Am I restricted to using only my upper body (where I can single-arm row about 120lbs), or can I use all of my body including my lower back (where I can do 300+lb back extensions)?

As I tell my players in my online WW2 games: You can't stop on a dime and you can't make jack-rabbit starts; and you can either move or shoot but not do both in a single turn (at least not well).

Lion, in a short word, no. Driver spaces are very tight, no where to do much of anything. I have not driven a WWII tank, but the M577s I spent so much of my life bouncing around in steer with the brakes. Not much advanced over WWII, but way better than the shermans.

Very easy to throw or break tracks at over 20 MPH.

The Sherman driver position has two steering levers in front of the seat. I think your feet would go either side of these but not sure.
I think you pull a lever toward you to brake the track on that side. But they're sort of big long vertical levers rather than like hand brakes to each side.
I'm not sure applying 300 Lb pressure to the end of one would be a great move, even if you could.
Tanks are much more fragile things than one might imagine.

I just recently bought the three Haynes guides on Tiger, Sherman and Churchill but only sort of flicked through and read the odd bit. They look pretty good actually.
As something of an aside.
They mention how easy the Tiger is to drive and how it's reasonably reliable so long as you stick to things it can do.