I'm working on Tamiya's M1A1 and I am finding that more than a few references show the APU mounted on the turret bustle as opposed to the rear of the tank as Tamiya has it. I have seen one photo showing Tamiya's placement of the APU and the photo looks to be in the Middle East ( It could also be Yakima Firing Range!) so Tamiya's version is correct I guess.
I've also purchsed Escelon's M1A1HA decal sheets for Operation OIF and the images and refs. show the APU's on the bustle.
What gives? looking forward to being educated!
Cheers
Joker

Joker,
Do you have the older Tamiya M1A1 kit or the newer M1A1/A2 kit?
The APU is now mounted in the buslte rack. If you have the older kit, that was based on vehicles during Operation Desert Storm. Then, most vehicle that had APU where mounted on the rear right.
Any of the tankers here can verifiy my reply. Vodnik also has a lot of reference on this too. Im just a MIssile Repairman and not a tanker, but I at least tried to help a little.

I served with the 24th ID (mech) in the late '80's and we had the hull mounted APU's on our M1 IP's. I'm not sure if 'A1's even had the hull mounted type. Dan

Pete is right, currently only turret mounted APUs are used and all versions of Abrams (except for M1A2SEP tanks which have internal APUs). I believe that hull mounted APUs are no longer used since mid '90s, but they were indeed used on M1A1HA tanks during Desert Storm and earlier on M1A1s and M1 IPs.

Pawel

Above posts are correct. Hull mounted APUs were used up untill about 1993, after that the turet mounted APU was introduced in the M1A1 Heavy Common (Heavy Armor, HA, to the modeling world), Heavy because it had new Depleted Uranium armor added, Common because it was now the common tank for US Army and USMC. Original M1A2s still had turret bustle APUs as well. The M1A2 SEP (Systems Enhancement Program) has the internal APU mounted in left rear of hull.

It sounds like Joker needs to get the new Tamiya kit that has the updated turret, especially if the Echelon decals are to be used.

As far as the 3rd ID goes, some tanks had them, and some did not. I have been working with a platoon sgt from 1-64 and in his platoon only one tank had the APU. I spoke with a LT from 4-64 and one per company had them. So, as far as those two battalions go it is the modeler's choice and there is no set tank within the platoon or company that had them. It seems to have been a personal choice; need for APU vs space for more stowage. Few were apparently worried about conserving fuel or having the engines off to be quiet.

I don't know about the Marine tanks for sure.

Also, as far as Echelon goes, I have been working with Lawrence Goh personally, and I can vouch for his thoroughness. He typically works directly with the source, and does not merely rely on photos for his decals.

Bob

Hello All,
From the Marine Corps Side of the House, we had the Bustle mounted APU's before the Army thought they were fashionalbe. The Bustle APU's have gone through 4 modifications. The new Tamiya one is the most accurate but there is always room to improve.

Semper FI
Andy

Well now I'm a little confused, what's the main differences between the M1A1 of the Desert Storm campaign and the M1A1/A2 of OIF?
I realize the track has changed and the APU location ( thanks for all the info!) the inclusion of CIP panels but what else would be noticable?
As well I've read Vodniks comparison ( outstanding article by the way if you haven't read it, take the time really worth it I thought) reagarding the major M1A1 releases, does this still hold true, Tamiya being the most accurate more or less.
Cheers and thanks for your patience.

Joker

As far accuracy goes it all depends. Many people like the DML kits but they seem to be over-engineered and some detail is soft. The Tamiya kit, which I have a lot of experience with, clicks together, and it has some nice detail that the DML kit does not. But, the Tamiya kit has too many leftovers from the old molds. Lots of people have a problem with there being no anti-slip on the Tamiya kit, but it is not a hard addition to make. And the Tamiya kit is a bit steep at $40+.

I like the Tamiya kit for what is out there at the moment, and I am currently superdetailing one after learning from building my first OIF one. But, apparently DML is soon coming out with what is supposed to be the end-all of M1A1 kits with all new tooling. We shall see.

Bob

Here is a rundown of M1 Varients:

M1 Abrams Tank Variants

The Abrams series started with the XM1 and then the M1 was fielded. Based on feedback from the troops in the field, certain modifications were added to those initial M1s in the field and to M1s during production. These became known as M1IP or M1 Improved Production. This variant was equipped with the M68 105mm main gun and had the asymmetrical 3-blast panel configuration. The engine access cover does not have the two rear inspection hatches. The front fenders do not have the “X” stamping and the head light guards are straight across as opposed to the later stepped type. Also, there are sponson boxes on both sides of the hull.

The M1A1 had two identical turret blast panels and was up gunned to the 120mm smooth bore cannon. It also added an NBC over pressurization system in place of the left hull sponson (storage) box. A "man hole cover" was added forward of the loader's hatch in anticipation of the development of Commander's Independent Thermal Viewer (CIT-V). The CIT-V was not installed on any M1A1 though.

Operation Desert Storm happened here in the timeline.

The next variant included changes the USMC required making the Abrams suitable for amphibious operations. It also had the depleted uranium mesh added to the forward slopes of the turret and hull. Because these changes incorporated a heavier armor and was now a common USA/USMC tank, it was referred to as the M1A1 Heavy Common. The modeling world refers to this as the M1A1-HA for "heavy armor", but this nomenclature is not used in the real armor world. About the same time as the M1A1HC changes were being made(still during ODS), the Abrams changed track from the angled-block T156 track to the square-block, “Bigfoot”, T-158 track.

The Marines made some cosmetic changes to their Abrams. They added a Missile Countermeasures Device (MCD) on top of the manhole cover. This is the square device that some people confuse for a version of the CIT-V. It serves a totally different purpose by directing anti-tank guided missiles away from the tank. The Marines do not use the CIT-V. They also swapped the Army 6-shot smoke grenade launcher for a double stach 4-tube version for 8 smoke launchers on each side of the turret.

The M1A2 added the CIT-V, which allows the commander to search and designate targets while the gunner engages the current target. This tank also incorporated an auxiliary power unit (APU or basically a generator) in the turret bustle rack to power the optics and electronics without the need to run the turbine engine. The APU has been retrofitted to many M1A1s as well. The M1A2 also required a new commander's cupola because the CIT-V data screens took up too much room in the commander's hatch.

The final variant (so far) is the M1A2SEP or Systems Enhancement Program. This upgraded several internal systems and allowed the APU to be moved from the turret bustle to the inside of the left rear hull (Under Armor APU or UAAPU). The engine changed as well and the CIT-V now uses a 2nd generation FLIR. Very few units in the Army use the M1A2SEP, which are mainly remanufactured M1IPs.

There are several additional rebuilt variants of the M1A1. One is called the M1A1-D and incorporates the digitized electronics package that is in the M1A2. Another is called the M1A1 AIM or Abrams Integrated Management Program which rebuilds older M1A1s to a zero time/zero hours "like new" condition.

That should cover all the different Abrams for you.

Okay, I think I'm getting this. Here's a really dumb question..what's a blast panel?
Thanks for your patience
Joker

the blast pannel is on the top of the turret behinf the Hatches...... it's designed to Blow out if the turret is struck by a round.

here's another 'd' question...what's that flat vertical box hanging on the rear panels of the abrams..usually present when mine rollers are in use. another APU? or it got something to do with explosive mines?

can you attach APUs and this device at same time..or 2 APUs at the same time? alot of modellers attach all sort of things on their tank..some relevant others not.

Outstanding, thanks to all for the information
Cheers
Joker

The box in the middle of the rear on mine plow tanks is the CLAMPS system, can't remember what the acronym stands for. It was designed to drop chalk behind the tank to mark the cleared lane through the mine field and guide other tank drivers on. It is no longer used since it was pretty ineffective.

As to two APUs, no. Only one APU is used at a time, either rear hull or turret bustle mounted, depending on above versions.

And finally, yes, hull mounted APU and CLAMPS were used at the same time during ODS. The CLAMPS was no longer used after ODS and won't be seen on a turret bustle APU tank.

hi there,...thanks heavyarty for the information...with all sort of gadgets attached to the hull..kinda hard to manuever an abrams?.. except if you're on the desert flowing mines. thanks again.

We were testing/using generators in the bustle rack in the late 80s in Germany, long before the USMC took delivery of any Abrams tank. The stateside units were testing the right rear hull mounted ones that eventually became standardized in CONUS. I never saw the hull mounted ones until I returned to the states in 1991. The hull ones vanished from 1st Cav tanks around 1991. I had to turn the battalion ones in when we drew M1A1HA in 1991. We never mounted them to the new tanks.

I imagine the APU move from the hull to the turret was a USMC driven requirement since those tanks have a tendancy to have the hull under water during amphibious operations. It makes sense that they would have been the ones to advocate a turret mounted APU since that little generator would not have done well if it had to get submerged in salt water with any frequency.

Gino, the acronym is CLAMS or Cleared LAne Marking System. We had troubles with them in Germany in the late 80s. We'd go through a ton of chem lights and half the time the little markers didn't fall out of the CLAMS upright or were sitting in a rut created by the tank tracks or mine plow. They were only used at night to guide follow on vehicle drivers through the cleared lane.

Rob, Thanks for the clarification. I was surprised you hadn't come up on this subject yet. Felt like I was out there w/o a wingman.

Yeah,
The best deal the Marine Corps ever got was from the Army. I was on the team the went to Germany and selected 200 tanks that the Army was forced to give us :-) . Your'e correct in saying that the Army was testing the generators in the Bustle, the APU that we see today and associate with the Tanks was a Marine Corps program that we tried to sell to the Army much like the MCD which initially the Army didn't want.

SF
Andy

House hold goods just got delivered this week and I'm living in a sea of boxes. Just got my DSL hooked up today, first time online in about a week. Besides, there are plenty of Abrams experts on this site. Any information I put out is most likely inaccurate or just plain wrong.

Hope you get settled in and back to modeling pretty quickly. Gotta love PCS moves. I may be making one this summer to Leavenworth, the fort, not the Federal Pen. Based on new ILE slating, it may not be till Dec for the Jan class though. We shall see.