LukeZ

Hi Guys,

I'm building my own tank control board since I don't care for the RX-18 and I think El-Mod is too expensive. I have the driving part working but I would like to make it as scale as possible and once I got into it, I realized there are a lot of details I had never thought of before.

Specifically, I'm thinking of how steering was accomplished in the full size tanks (I say "was" because I guess I'm mostly interested in WWII-era tanks for now).

From the reading I've done it appears there were actually multiple methods and it differed by tank. Some like the Tiger had rather sophisticated transmissions that allowed for multiple turning radii but others (of which I found less information on) I guess only had one turning radius? This is a bit unclear. I guess for these latter types (the Panther for example), at any given forward gear they could only slow down the inside track by a set amount? I'm not sure I even understand the difference between a set turn radius and an adjustable one.

What does seem clear, and which I wasn't very sure about in the beginning, is that most tanks of that period accomplished steering by slowing down the inside track only, and not by also speeding up the outside as well. Slowing down the inside track was accomplished usually by a clutch/brake mechanism. I think modern tanks have a more sophisticated approach.

What I was also surprised to find out is that not all tanks could perform a neutral turn (each track rotating in opposite directions), but I still don't have a very comprehensive list of which could and which couldn't. I know the Tiger could. But maybe someone can tell me, it probably wasn't possible to perform a neutral turn and then immediately launch into forward movement? It seems like there must have been some gear shifting done in-between. I could model this in my software but it helps to know as many details of how it was done in real life. On our stock Heng Long models, of course, you can super spin and then go-for-blazes forward without batting your eye. This can be fun for fooling around but doesn't look very scale.

I read one description of the Panther where it was recommended crews didn't turn while in reverse, in order to save wear on the final drive... Good grief, there sure are a lot of exceptions to account for in trying to come up with a realistic drive system.

Anyway I know most of us haven't spent a lot of time driving around full size Tigers and Shermans but there is so much knowledge on this forum I figured I was bound to get some useful input from the folks here. If anyone knows of resources or just has details on the drive/steering parameters of a specific tank I'd be quite happy to have it. It would be a simple matter to set up profiles so that I could select a certain tank and have a different set of steering/drive behaviors for each one.


Luke

edoubleaz

My Feedback: (1)

Ambitious project. As a battler, I have to ask if combat functions are part of your software model?

karel47

very daring approach for driven your tank, keep me posted looks very tempting would be the ultimate expierence for serious tankers if you get it started

LukeZ

Yes, I'd like eventually to include battle and sound functionality. Who knows if by then I won't have spent twice the amount of an El-Mod. However, don't get too excited, I have not gotten into the battle stuff yet and so I can't say what challenges it will hold. I expect this process to take quite some time. For now I am focused on the drive functionality.

Whatever I come up with, and it may not be much, I will make open source. I don't know how many other programmers there are in this hobby but perhaps I should start another thread to gauge the interest of a group collaboration.


Luke

pattoncommander

Tank transmissions are as varries as the number of tanks that were fielded. The first tanks to have a sucessfull neutral steer=pivot were the M-46 and M-41, with the Allison Cross Drive transmissions. The tiger, Panther and KT could make a neutral steer, but it was extremely slow and very hard on the tracks and suspension. The tiger had a complicated gearshift comprised of a directional shift for forward or reverse, which gave it 8 gears in each direction. After selecting direction, it had to shifted from 1-4 and moved to another position for 5-8. I believe the Panther had basically the same type tranny. Earlier Panzers did not have pivot capability and shiftinfg was very simple. The M-3A1 Stuart, M-3 Mediums and Shermans all had a 5 speed crash box which was totally unsyncronized and one had to double clutch up and down in all gears. It took some training to get used to shifting a Sherman. The M-5A1 Stuart had a semi auto transmission similar to the Buick Dynaflow, which was very reliable and fast. The shifter was almost a toy in size and easy to shift. The M-26 had the Ford torquematic transmission which was semi auto but the tank still had laterals to steer and stop. The M-41-46-48-48 thru the M-60s all had the Allison CD with very simple and fast selector..N-L-H.R. The tanks could neutral steer by selecting neutral and steering in the direction you wanted to move. M-41 had a T bar, like a bicycle.. The M-46 and 47 had a wobble stick, which served as a gearshift and steering in one controller. A latch was pressed by the heel of the hand, and moved into gear....no latch from L-H and the wobble stick was simpy pushed-pulled in the steering direction. .Allison CD trannies were reversed when shifting in reverse....to steer right, the driver had to steer left etc. Simple way to remember...to back up left, steer the front of the tank in the direction of the wobble stick/t-bar,wheel. The M-48s had an oblong steering wheel with the shifter behind it...almost like a car. M-60s had a steering wheel but shifter seperate on the floor. T-34s had a horrible transmission wheh they forst came out, requiring the bow gunner, sometimes with a hammer or steel bar to assist in shifting. The T-34/85 had a better transmission. Later T-54-55s had a "slam it in" tranny which was not a smooth ride. The T-64 was fun to drive. Later ones T-70 etc ???? I do not believe any Russian tanks have pivot.

Panther F

I'll just stick with Tamiya electronics. If driven sensibly the end result is realistic, especially with some work on gearbox and motor systems. If you IR battle with your tanks most would not even care.

But goodluck with your project!


- Jeff

LukeZ

PattonCmdr, that is a lot of information to digest! Thanks so much for your very detailed post. Obviously it will be impossible or impractical to model all of this in a model but it does give me some good ideas. Jeff is also right, a lot of the final result, in terms of how the tank looks while driving, is up to the driver.

Luke

pattoncommander

For WW II stuff, to replicate actual driving, best to "stutter" the turns. Tanks with laterals normally steered with a pull-release action and rounded a corner in steps..Not jerk, jerk,, but a good pull and release. It was also done to get lube to the clutch asemblies. This was particularly important on soft sand or mud....as you could easilly drop a track. To try and lock one track and make a tight turn was not a good idea. A long, slow turn was no problem. With T-34,s loose gravel was murder for the tracks, as small rocks would get into the wheels and bend the guide tooth....this resulted in the tank being imoblized and a four hour job of dropping the track and replacing the bad block (every 2nd had a tooth). This, from a former T-34 driver I met. Modern tanks have a much better suspension.

GatlingGun

So the blokes that are putting weed whacker motors in tanks how are they hooking themup and steering them ????????????

city hunter

Reading this thread sparked my interested in the tigers power transmission, and I found a great page describing in detail how the unit was operated. Apparently it was quite a easy tank to drive as everything was hydraulically assisted making shifting and turning etc.. light and easy.

http://www.alanhamby.com/transmission.shtml

There is a little footage of a tiger neutral steering in this video.

http://www.youtube.com/watch?v=jzWAi...layer_embedded

lthump

I believe Tiger tanks often used nuetral steer when aiming , to speed the process up as turret traverse was slow.

Wight

I think the point has been missed that you are trying to replicate the action of a real tank being driven off one powerful engine to models that are powered by two weaker motors.I think my point is that most of our tanks perform well in a straight line but suffer when turning due to the fact that half your power is lost by turning a motor down or off altogether.
I would think the older clutch driven Tamiya's are the closest to operating like the real thing and they can do it on a single esc and a servo.
I just do not think you can replicate this with electronics because no matter what you do,as soon as you turn off one motor you have lost 50% of the available torque.
I think the reason modern Tamiya's speed up on the outside track when turning is to attempt to add more power to the only driving track.My Tamiya truck is like that in a way also,when the trailer is hooked up the electronics speeds up the motor a bit to attempt to compensate for the extra load.
If I've missed the point on this thread I'm sorry,I'm very good at that!
Anyway whatever you decide to try,good luck with it and keep us posted on your progress.

LukeZ

This "pull and release" action was basically an application of brakes to the inside track, right? And usually while moving forward, the inside track would be braked to slow down, but not to stop completely? That would be quite a jerky turn if so.

But I agree, this effect could simply be replicated by the driver.

Wight, no major point to the thread intended from me, just an interesting discussion of how the full sizes steer, as I really didn't know. There is going to be a real limit to how realistic a model will ever be, I just wanted to know the basics so I didn't have my Sherman doing super spins or things that were clearly outside the realm of possibility. As for the rest I think more and more it is just up to the guy behind the sticks to try to drive in a realistic manner, and not shooting along at a hundred miles an hour over all obstacles.

A smooth, well-lubricated gearbox in a model also helps considerably to avoid jerking, and allows a slower sustained speed.


Luke

sevoblast

Turret traverse on Panthers and Tigers was power, running of a PTO from the main drive shaft. Read TiC and you will not see complaints from the vets who actually fought these tanks. They also had a hand traverse, used for fine adjustment in aiming, and in a pinch could be used for traverse. Traverse speed was in direct relationship to engine revs, and you will read often of the gunner telling the driver to crank it up.

Tanque

Here how I do it although mine aren't weed whacker motors:

http://tanks.linite.com/Gearbox.html

Jerry

Rex Ross

Tanque......I really like the exhaust smoke! It's perfect.........

GatlingGun

THX ! Seems it is not as simple as some would believe.

Tanque

No it isn't.

city hunter

Amazing work on that transmission setup. Are you using the motor for a starter? Do you have any kind of motor setup for a alternator? Wold be pretty cool if you could basically have a batter set in it and a electric start.

I really do like the idea of that 4 stroke engine for a powerplant. How reliable are they?

Tanque

All of my tanks use an electric starter.

Jerry

pattoncommander

Correct...Shermans and others with a 5 speed crash box and driver busy with double clutching had a harder time driving. Any tank with laterals, used the pull release turning on hard turn,....a slow gradual turn, was less of a problem but still, couldn't keep that lateral back too long without starving the steering clutch of oil and wearing down the pads. Even auto or semi auto trannies had to be treated well. Again, hard turns and especially neutral steer was hazardous for loosing a track or tearing up road wheels.

Several sources tell that the Tigers were easy to drive and didn't need much muscle. Once a driver got used to the shifting patterns it was apparently very easy.

City hunter...as I wrote,,,,,Neutral steer with Tigers was VERY slow and also very risky on the track and suspension. Immagine the fun of having to lay out and put the track back on in that mud. [:@]

wbn

I found an article about steering of tracked vehicle, it mentioned several steering methods, from simple brake turn to complicated one with several differential to achieve powered turn, an it also mentioned the pros and cons of each methods.

http://www.gizmology.net/tracked.htm

rva1945

You Pattoncommander, are an Encyclopedia related to tanks!!

rva1945

So you have a 1/25 Tank? I'd love to see it. Did you convert it to RC?

Enthusiastic.Tanker

I’m sure someone has already answered you on this but for some examples Sherman tank had a braked differential and the tiger had a double differential. Some quick google searches will give you lots of information on how these systems work.