Tracked Vehicle Speed Comparison

[MDF]

A while back, I threw together a mission to test the straight line speed of most of the tracked combat vehicles in SB. Here are the results of a single vehicle of each type moving at top speed in a straight, 4km line over flat ground (the default terrain in the mission editor). The fastest was the M1(IP). (The M1A0 may be equally speedy, with the discrepancy possibly due to inexact placement at the starting line; discrepancies among the Leo1 family may be explained likewise). All results are expressed as a percentage of the M1(IP)'s speed, sorted from fastest to slowest:

M1(IP)....................... 100.00

M1............................ 99.80

BMD-2....................... 98.13

T-80U........................ 97.19

BMP-3........................ 94.48

Leopard 2A5................ 92.32

M1A1......................... 92.30

Leopard 2A4................ 91.23

Leopard 2A5DK............ 88.55

Leopard 2A5A1DK......... 88.55

M1A1(HA)................... 88.47

Jaguar 1A3................. 88.42

Leopard 2A5A2DK......... 87.26

Ulan.......................... 87.13

Leopardo 2E................ 87.00

Strv-122.................... 87.00

M1A2 (SEP)................ 85.84

M113AS4................... 80.90

M113 G3 TOW............. 80.77

M113A3..................... 78.21

BMP-1....................... 77.58

Warrior (ODS)............. 75.88

Pizarro...................... 75.50

YPR65 pri .50............. 74.26

T-90A....................... 74.18

M2A2 (ODS)............... 73.04

M3A2 (ODS)............... 73.04

BMP-2....................... 70.89

Leopard 1A5............... 69.90

Leopard AS1............... 69.90

Leopard 1A5DK............ 69.83

Leopard 1A2............... 69.77

Leopard 1V................. 69.77

YPR65-pri................... 67.24

YPR65 PRAT................ 67.24

M113A1..................... 67.09

M113A2..................... 67.09

T-72M1..................... 66.40

T-72M....................... 65.82

T-72M4..................... 65.72

T-72B (early).............. 65.32

T-64A....................... 65.26

Marder1A3.................. 63.36

T-64B........................ 62.81

M901......................... 62.43

T-72B........................ 62.38

Challenger 2................ 60.91

AMX-13...................... 56.65

T-55.......................... 56.42

PT-76........................ 56.07

T-62......................... 54.35

M60A3 (TTS).............. 49.99

Centurion................... 42.46

Attached is a .jpeg with the results in graph form:

One of these days, I'll do a similar test of each vehicle over more complex terrain, and a test of sprint speed over a small distance (~100m).

Edited January 27, 2014 by MDF

[Marko]

A while back, I threw together a mission to test the straight line speed of most of the tracked combat vehicles in SB. Here are the results of a single vehicle of each type moving at top speed in a straight, 4km line over flat ground (the default terrain in the mission editor). The fastest was the M1(IP). (The M1A0 may be equal speed, with the discrepancy possibly due to inexact placement at the starting line; discrepancies for the Leo1 family may be explained likewise). All results are expressed as a percentage of the M1(IP)'s speed, sorted from fastest to slowest:

Attached is a .jpeg with the results in graph form:

One of these days, I'll do a similar test of each vehicle over more complex terrain, and a test of sprint speed over a small distance (~100m).

Great work MDF.

[MDF]

Great work MDF.

Thanks. It was the recent thread on the proposed diesel replacement engine for the M1 that reminded me of this.

If someone could educate me....as I understand it, in the late 70's/early 80's, the advantages and disadvantages of the M1 turbine engine versus diesels were:

Advantages

--Better acceleration

--Quieter

--Smaller (meaning lighter and more compact, so more weight and/or space available for other things)

--Simpler design and, therefore, simpler (not necessarily less man hours, but less skill required) to maintain

Disadvantages

--Greater fuel consumption

--Increased thermal signature

-- High-temp heat exhaust makes it difficult for infantry to follow immediately behind

-- At least some maintenance burdens are greater (e.g., regularly cleaning air filters)

Am I correct? What else am I overlooking?

As for the acceleration advantage, I assume this means that the M1 could go from 0km/h to full speed more quickly than a diesel-equipped contemporary (e.g., Leo II). Does this also translate, to some degree, to better cross-country mobility, or at least better speed going uphill?

[MAJ_Fubar]

In my experience the Leo 2 tends to have a slightly higher top speed and is quicker off the line due to lag with the turbine, but the M1 has an overall quicker "dash" speed, so they tend to cross the line about the same time...

[lavictoireestlavie]

MDF, very nice work indeed !:luxhello:

[dejawolf]

Thanks. It was the recent thread on the proposed diesel replacement engine for the M1 that reminded me of this.

If someone could educate me....as I understand it, in the late 70's/early 80's, the advantages and disadvantages of the M1 turbine engine versus diesels were:

Advantages

--Better acceleration

--Quieter

--Smaller (meaning lighter and more compact, so more weight and/or space available for other things)

--Simpler design and, therefore, simpler (not necessarily less man hours, but less skill required) to maintain

Disadvantages

--Greater fuel consumption

--Increased thermal signature

-- High-temp heat exhaust makes it difficult for infantry to follow immediately behind

-- At least some maintenance burdens are greater (e.g., regularly cleaning air filters)

Am I correct? What else am I overlooking?

As for the acceleration advantage, I assume this means that the M1 could go from 0km/h to full speed more quickly than a diesel-equipped contemporary (e.g., Leo II). Does this also translate, to some degree, to better cross-country mobility, or at least better speed going uphill?

the smaller size of the turbine is offset by the larger fuel tanks required, and enormous heat exchanger, so in the end, not that much of an advantage.

[daskal]

WoW - Challenger 2 so far down the list - even beaten by the T72.

[DarkLabor]

WoW - Challenger 2 so far down the list - even beaten by the T72.

Wich is not surprising at all if you consider the power to weight ratios.

[MDF]

the smaller size of the turbine is offset by the larger fuel tanks required, and enormous heat exchanger, so in the end, not that much of an advantage.

Aha. Interesting!

[MDF]

WoW - Challenger 2 so far down the list - even beaten by the T72.

Yeah, that really jumped out at me too. I wonder (and I don't mean this as a dig at the Royal Army) if it has good reverse speed. If so, it might still be extremely effective in a delay-oriented defensive scheme against the Soviet HordesTM

[Tjay]

Yeah, that really jumped out at me too. I wonder (and I don't mean this as a dig at the Royal Army) if it has good reverse speed. If so, it might still be extremely effective in a delay-oriented defensive scheme against the Soviet HordesTM

Well, it certainly REVERSES faster than the T72. But then so does a sloth. :clin:

[Gibsonm]

Yeah, that really jumped out at me too. I wonder (and I don't mean this as a dig at the Royal Army) if it has good reverse speed.

Just as an aside, The British Army does not have a "Royal" prefix, unlike the other services in the UK.

[hoggydog]

The Royal prefix does however appear in many sub-units of the British army like the Royal Armoured Corps or the Royal Electrical and Mechanical Engineers (REME).

[Gibsonm]

Yes sorry if I implied that nothing in the British Army has a "Royal" prefix.

Almost all Corps (and many of the Regiments / units with their respective Corps) carry the "Royal" honourific in their title.

[MDF]

The Royal prefix does however appear in many sub-units of the British army like the Royal Armoured Corps or the Royal Electrical and Mechanical Engineers (REME).

You know, it sounded sort of funny as I was typing it, but I didn't get much sleep last night and I guess the cognitive dissonance was insufficient to pierce the grogginess. I was originally going to say "BAOR," but figured that was too narrow in scope.

[jazjar]

This got me interested in the acceleration question, how fast does one tank get to a certain speed than another etc. and I decided to test the M1 family on flat, green ground. Since I noticed 0-20kph happened in a blink of an eye for all of them, I decided to use 20-45kph. ( I wanted to use 50 but the SEP didn't even go that fast. )

M1: 9.2s

M1(IP): 9.4s

M1A1: 11.8s

M1A1 (HA): 14.3s

M1A2 (SEP): 16.6s

Do take these with an uncertainty of ~0.2 seconds, my reaction time. Hopefully I will soon get the chance to compare this with the Leopard.

[Ssnake]

If someone could educate me....as I understand it, in the late 70's/early 80's, the advantages and disadvantages of the M1 turbine engine versus diesels were:

Advantages

• Better acceleration
• Quieter
• Smaller (meaning lighter and more compact, so more weight and/or space available for other things)
• Simpler design and, therefore, simpler (not necessarily less man hours, but less skill required) to maintain

Disadvantages

• Greater fuel consumption
• Increased thermal signature
• High-temp heat exhaust makes it difficult for infantry to follow immediately behind
• At least some maintenance burdens are greater (e.g., regularly cleaning air filters)

Am I correct? What else am I overlooking?

On the face of it, it's still true, but as so often, things get a bit more complex if you look deeper into the issue. The heat exchanger was already mentioned, and one thing that always struck me as a distinct disadvantage of the turbine is that the heat exchanger is welded in a rather complicated fashion to the turbine, and the weld lines must be of really good quality to prevent leaks. Only few specialists can do that, and you can't do it in the field but need a dedicated repair facility - and you can't swap a turbine without first disconnecting (=breaking the welding) from the heat exchanger. So, it may be less crew and low level maintenance, but swapping out a damaged engine in under 40 minutes as can be done with the Leo 2 is simply impossible, and it looks as if the maintenance effort rises at the higher echelons. That probably was considered an acceptable trade-off (you want as little maintenance burden at the crew level as possible), but it somewhat reduces the advantage that the turbine may seem to have at first sight.

As far as the volume argument goes, the turbine itself is smaller, but one should look at the whole package (like how much volume do you need for fuel to reach an identical operational range as a diesel engine; what about the transmission gears, heat exchanger, etc.) And it's not as if no progress has been made on the compactness of diesel engines in the past 35 years. So, for comparison (per Rolf Hilmes' "Kampfpanzer heute und morgen", pages 270ff.), let's have a look at the specific power output (power to volume ratio) of different engines, turbine, diesel, and hyperbar:

• The Leo 2's MT833 Ka-500: 689kW/m³
• The Challenger 2'S Perkins Condor: 878kW/m³
• The Leclerc's Wärtsilä Hyperbar: 549kW/m³
• M1's LV 100 gas turbine: 709kW/m³
• MT881 Ka-501 ("Euro Powerpack") Diesel: 894kW/m³
• MT883 Ka-524 (intended for EFV): 1,150kW/m³ (!)

So, the difference was never very big to begin with, and modern Diesel engines offer a substantial advantage of power output per volume. Interestingly, the Hyperbar seems to marry the disadvantages of both technologies - the high fuel consumption of the gas turbine with the higher crew level maintenance effort of a Diesel engine, and the thermal signature of an exhaust carrying soot particles...

The thermal signature is an interesting aspect. Yes, the M1's gas exhaust is much hotter, and that brings a host of issues of its own. Yet, the turbine exhaust contains virtually no particles and as such is invisible in a thermal sight. A tank accelerating behind a ridge line will belch a soot cloud which is easily visible in a thermal sight, giving you a bit of a clue where a target might soon pop up.

On the other hand, I've seen an M1 driving into a battle position in front of a tree. What looked like a good idea in the optical spectrum to mask the silhouette was disastrous in the thermal spectrum, as the hot exhaust were collected by the tree's foliage, heating up the entire tree within 20 seconds. You could literally watch how the tree lit up from below, turning from ambient to brightly lit in the thermal spectrum in no time (this is an effect that we do not yet simulate in SB Pro). In a forested environment, that's a huge tactical issue (IF the enemy is equipped with thermals). It will happen also with a diesel engine over time - make no mistake - but much, much slower.

As for the acceleration advantage, I assume this means that the M1 could go from 0km/h to full speed more quickly than a diesel-equipped contemporary (e.g., Leo II). Does this also translate, to some degree, to better cross-country mobility, or at least better speed going uphill?

Cross-country mobility depends on a number of factors, the ability to accelerate is certainly important. But you also need to factor in ground pressure, median maximum pressure (MMP), travel length of the roadwheel suspension, and overall weight of the vehicle. In Iraq, multiple road banks simply collapsed under the sheer weight of the Abrams - torque won't save you there. In a swampy area, a low MMP and low ground pressure in general will help you more than torque (and no, you can't just make the tank longer, as it'll be harder to steer around corners - and no, you can't make the tank wider, unless you give up on rail transportability, or change the rail gauge everywhere (good luck with that)).

[Invader ZIM]

the M1's gas exhaust is much hotter, and that brings a host of issues of its own. Yet, the turbine exhaust contains virtually no particles and as such is invisible in a thermal sight. A tank accelerating behind a ridge line will belch a soot cloud which is easily visible in a thermal sight, giving you a bit of a clue where a target might soon pop up.

On the other hand, I've seen an M1 driving into a battle position in front of a tree. What looked like a good idea in the optical spectrum to mask the silhouette was disastrous in the thermal spectrum, as the hot exhaust were collected by the tree's foliage, heating up the entire tree within 20 seconds. You could literally watch how the tree lit up from below, turning from ambient to brightly lit in the thermal spectrum in no time (this is an effect that we do not yet simulate in SB Pro).

That's been a headache with the turbine since it's inception. In one way, I think we were lucky that the Soviet's didn't have much in the way of thermal equipped vehicles until pretty recently. Now it's much more of an issue, and a pain to address the problem.

I vote for the intermat option, as well as the extra arat tiles to reduce it's signature, but once that exhaust hits anything that conducts heat all bets are off. It would be awsome if eventually this kind of stuff could be simulated, it forces trainees to be mindful of their thermal signature as well as their visible wavelength signature.

[MDF]

On the face of it, it's still true, but as so often, things get a bit more complex if you look deeper into the issue. The heat exchanger was already mentioned, and one thing that always struck me as a distinct disadvantage of the turbine is that the heat exchanger is welded in a rather complicated fashion to the turbine, and the weld lines must be of really good quality to prevent leaks. Only few specialists can do that, and you can't do it in the field but need a dedicated repair facility - and you can't swap a turbine without first disconnecting (=breaking the welding) from the heat exchanger. So, it may be less crew and low level maintenance, but swapping out a damaged engine in under 40 minutes as can be done with the Leo 2 is simply impossible, and it looks as if the maintenance effort rises at the higher echelons. That probably was considered an acceptable trade-off (you want as little maintenance burden at the crew level as possible), but it somewhat reduces the advantage that the turbine may seem to have at first sight.

As far as the volume argument goes, the turbine itself is smaller, but one should look at the whole package (like how much volume do you need for fuel to reach an identical operational range as a diesel engine; what about the transmission gears, heat exchanger, etc.) And it's not as if no progress has been made on the compactness of diesel engines in the past 35 years. So, for comparison (per Rolf Hilmes' "Kampfpanzer heute und morgen", pages 270ff.), let's have a look at the specific power output (power to volume ratio) of different engines, turbine, diesel, and hyperbar:

• The Leo 2's MT833 Ka-500: 689kW/m³
• The Challenger 2'S Perkins Condor: 878kW/m³
• The Leclerc's Wärtsilä Hyperbar: 549kW/m³
• M1's LV 100 gas turbine: 709kW/m³
• MT881 Ka-501 ("Euro Powerpack") Diesel: 894kW/m³
• MT883 Ka-524 (intended for EFV): 1,150kW/m³ (!)

So, the difference was never very big to begin with, and modern Diesel engines offer a substantial advantage of power output per volume. Interestingly, the Hyperbar seems to marry the disadvantages of both technologies - the high fuel consumption of the gas turbine with the higher crew level maintenance effort of a Diesel engine, and the thermal signature of an exhaust carrying soot particles...

The thermal signature is an interesting aspect. Yes, the M1's gas exhaust is much hotter, and that brings a host of issues of its own. Yet, the turbine exhaust contains virtually no particles and as such is invisible in a thermal sight. A tank accelerating behind a ridge line will belch a soot cloud which is easily visible in a thermal sight, giving you a bit of a clue where a target might soon pop up.

On the other hand, I've seen an M1 driving into a battle position in front of a tree. What looked like a good idea in the optical spectrum to mask the silhouette was disastrous in the thermal spectrum, as the hot exhaust were collected by the tree's foliage, heating up the entire tree within 20 seconds. You could literally watch how the tree lit up from below, turning from ambient to brightly lit in the thermal spectrum in no time (this is an effect that we do not yet simulate in SB Pro). In a forested environment, that's a huge tactical issue (IF the enemy is equipped with thermals). It will happen also with a diesel engine over time - make no mistake - but much, much slower.

Cross-country mobility depends on a number of factors, the ability to accelerate is certainly important. But you also need to factor in ground pressure, median maximum pressure (MMP), travel length of the roadwheel suspension, and overall weight of the vehicle. In Iraq, multiple road banks simply collapsed under the sheer weight of the Abrams - torque won't save you there. In a swampy area, a low MMP and low ground pressure in general will help you more than torque (and no, you can't just make the tank longer, as it'll be harder to steer around corners - and no, you can't make the tank wider, unless you give up on rail transportability, or change the rail gauge everywhere (good luck with that)).

I forgot to thank you for this post. Very informative!