On Chimera again ... (designer's notes)

Woodwind
Specialist
Posts: 14
Joined: Tue 21 Jan 2014 18:12
Contact:

Re: On Chimera again ... (designer's notes)

Postby Woodwind » Fri 24 Jan 2014 13:10

another505 wrote:then unfortunately it is not designed like the strv 103

able to move up and down and rotate to traverse the gun :D


No - the Chimera was not an S-tank design.

The S-tank (as we called it in the UK), has a very low "L over C ratio" - that is to say, the ratio of the track length on the ground to the width between track centres. If it is much below 1.1 to 1, where the length and width create a "square" on the ground, the vehicle can be more easily skid steered than one that has a higher ration where the track is longer. The advantage of the latter is that the vehicle is more stable traveling at speed and it can cross wider ditches.

The square ratio means that you can achieve small adjustments in traverse (or "line") relatively easily and with less power than a conventional track layout. The S-tank also had variable height suspension needed for the elevation of the gun - and that had to be designed in from the start. The hydraulics have to be very good to give the sort of aiming precision needed for long-range shoots. (You could of course had a vehicle where the traverse was provided by the track and elevation by a conventional gun laying system - although that would have left another hole of course.)

Don't forget that we were working from what was essentially a Chieftain base with a few add-ons that were in UK service at that time - the suspension came off the Challenger 1 tank that had entered service in 1983.

Sleksa
Lieutenant Colonel
Posts: 2265
Joined: Tue 14 May 2013 12:26
Contact:

Re: On Chimera again ... (designer's notes)

Postby Sleksa » Fri 24 Jan 2014 14:57

Woodwind wrote:Don't forget that we were working from what was essentially a Chieftain base with a few add-ons that were in UK service at that time - the suspension came off the Challenger 1 tank that had entered service in 1983.


Do you have any estimates on the complexity and time needed for converting the 600 chieftain hulls into the chimeras, like how many other hull parts from mothballed vehicles were needed and in what quantities they would be available?

How about the spare parts for maintenance during prolonged fighting? To me it seems like a rather big operation, especially during a state of emergency/war brought upon by the possible soviet offensive. But I assume your project team experimented/calculated the possible gains these converted vehicles would have on the conflict were well worth the effort?
Image

Woodwind
Specialist
Posts: 14
Joined: Tue 21 Jan 2014 18:12
Contact:

Re: On Chimera again ... (designer's notes)

Postby Woodwind » Fri 24 Jan 2014 17:17

As far as the bigger picture was concerned, we did not have to look at or justify the vehicle on a whole life cost basis - other than to consider how we could make the best use of the existing Chieftain fleet by providing a low-cost TD variant. Given that the assumption was the the tanks were reaching obsolescence, the majority of the parts would have been donor items from the existing fleet. Whether or not we were going to go for 600 TDs is another moot point. If not, then presumably there would have been a major pile of spares sitting there.

You refer to a state of emergency. At the time there was no real feeling that this was an emergency amongst people in the army as far as I was aware. We did not view the project as being a reaction to a crisis of any sort. If the design had actually been adopted (highly unlikely in my view) then the normal procurement processes would have kicked in and we would have been waiting for many years before it came into service (slated for the early 1990s of course). I think the UK's "emergency reaction" (if you can call it that) to the 1983 freeze in relations with the Soviets was getting the Challenger 1 into service a bit quicker.

User avatar
Mitchverr
More than 10 000 messages. Soldier you are the leader of all armies!
Posts: 10646
Joined: Sat 24 Mar 2012 18:08
Contact:

Re: On Chimera again ... (designer's notes)

Postby Mitchverr » Fri 24 Jan 2014 17:21

I always thought that the challenger 1 was more to bail the nice company out of its pickle as i heard that they were waiting for something else and there was quiet heated debates as to not wanting the challenger 1 as it was renamed.
Image

Sleksa
Lieutenant Colonel
Posts: 2265
Joined: Tue 14 May 2013 12:26
Contact:

Re: On Chimera again ... (designer's notes)

Postby Sleksa » Fri 24 Jan 2014 19:42

Woodwind wrote:As far as the bigger picture was concerned, we did not have to look at or justify the vehicle on a whole life cost basis - other than to consider how we could make the best use of the existing Chieftain fleet by providing a low-cost TD variant. Given that the assumption was the the tanks were reaching obsolescence, the majority of the parts would have been donor items from the existing fleet. Whether or not we were going to go for 600 TDs is another moot point. If not, then presumably there would have been a major pile of spares sitting there.

You refer to a state of emergency. At the time there was no real feeling that this was an emergency amongst people in the army as far as I was aware. We did not view the project as being a reaction to a crisis of any sort. If the design had actually been adopted (highly unlikely in my view) then the normal procurement processes would have kicked in and we would have been waiting for many years before it came into service (slated for the early 1990s of course). I think the UK's "emergency reaction" (if you can call it that) to the 1983 freeze in relations with the Soviets was getting the Challenger 1 into service a bit quicker.


My bad, I didn't mean that the obsoletion of the chieftain fleet was a state of emergency but rather that the plan was for a portion of the chieftains would be converted into chimeras at the start of a conflict (such as a soviet invasion of the mainland europe).

I'm not sure if the terms are corresponding since I'm Finnish but we refer to the preparation moments before war liberally translated as a exceptional/emergency state or a grey phase of the conflict.
Image

Woodwind
Specialist
Posts: 14
Joined: Tue 21 Jan 2014 18:12
Contact:

Re: On Chimera again ... (designer's notes)

Postby Woodwind » Fri 24 Jan 2014 19:53

I understand your question now.

No - I do not think that was ever the intention. I believe that the timescale of the transition to war (TTW) would have been far too rapid to consider that sort of response. I doubt that we would have had time to even get our UK-based forces across and into position before the Sovs had launched across the IGB. I think it was the East Germans who would have been the fastest though. We found out after the German unification that the Warsaw Pact had thousands of concrete vehicle hides just behind the IGB and that they could possibly have swarmed across the border before we had even properly deployed from our bases in West Germany if they had wanted to.

The TTW phase was critical and a lot of effort was expended in making it as long as possible so the West had a chance of being on the battlefield when WW3 started ! To tool up for a new vehicle would have taken months and years even in a crisis. IMHO of course.

Sleksa
Lieutenant Colonel
Posts: 2265
Joined: Tue 14 May 2013 12:26
Contact:

Re: On Chimera again ... (designer's notes)

Postby Sleksa » Fri 24 Jan 2014 20:26

Woodwind wrote:I understand your question now.

No - I do not think that was ever the intention. I believe that the timescale of the transition to war (TTW) would have been far too rapid to consider that sort of response. I doubt that we would have had time to even get our UK-based forces across and into position before the Sovs had launched across the IGB. I think it was the East Germans who would have been the fastest though. We found out after the German unification that the Warsaw Pact had thousands of concrete vehicle hides just behind the IGB and that they could possibly have swarmed across the border before we had even properly deployed from our bases in West Germany if they had wanted to.

The TTW phase was critical and a lot of effort was expended in making it as long as possible so the West had a chance of being on the battlefield when WW3 started ! To tool up for a new vehicle would have taken months and years even in a crisis. IMHO of course.


Thanks. It sounded to me like the conversion process was incredibly quick and/or simple for some reason and allowed massive conversions in a short perioid of time which made me wonder if there was a pool of readily available parts in mothball/storage somewhere apart from the chieftain hulls.

Looking at the sketch and the model made by Bovington and the one in the game, the cannon seems to be quite low on the chassis. Did you also consider placing the gun higher on the vehicle like in the swedish S-tank for a even more lowered silhouette? Or was this not possible due to the chieftain's hull design or some other factor?

I had a chance to read some newspapers and magazines from the 70's and at my grandfather's house during the last xmas and I came across an article that was about a new soviet doctrine that was worrying NATO and Finland at the time. It's design was basically to launch soviet forces as quickly and as far inside the west as possible to force the western forces to either deploy the nuclear arsenal at their own encircled/combating troops or risk losing the forward deployed nuclear arsenal to the soviet forces.
Image

Woodwind
Specialist
Posts: 14
Joined: Tue 21 Jan 2014 18:12
Contact:

Re: On Chimera again ... (designer's notes)

Postby Woodwind » Fri 24 Jan 2014 21:31

The gun could not go higher as it made the overall vehicle too high - if you take the max depression and then see where the roof has to be to accommodate the top rear edge of the breech block on full recoil , it would have raised the overall height by too much. Part of a TD's strength is that it has a low profile compared to a tank in general terms.

The Soviet strategy you refer to might have been the manoeuvre force principle where a self-contained army or corp effectively drove as deep as it could then defended its patch until joined by the main forces. It was linked to the other side of the coin called FOFA - follow on forces attack where one tried to prevent the main forces joining it - as well as also trying to hit second echelon forces in general - including log support elements; sometimes this involved fairly deep strikes. All this sort of stuff got really mixed up at the end of the day - and then the Wall came down.

Got to go now - will respond to other points tomorrow

User avatar
another505
More than 10 000 messages. Soldier you are the leader of all armies!
Posts: 13128
Joined: Sun 21 Jul 2013 05:18
Location: Hiatus
Contact:

Re: On Chimera again ... (designer's notes)

Postby another505 » Fri 24 Jan 2014 21:50

If i remember correctly, the S tank strv 103 was considered by UK to buy

but the idea was scrapped as the tank was made precisely for Swedish tactics and region..
Image
Of Salt

User avatar
ohslowpoke
First Sergeant
Posts: 208
Joined: Mon 16 Dec 2013 17:29
Contact:

Re: On Chimera again ... (designer's notes)

Postby ohslowpoke » Sun 22 Nov 2015 22:15

I know this is a significant bump to this topic, but I was curious if Woodwind was still around; if so I would love to be in contact him via private message or email.

Return to “Wargame : AirLand Battle”

Who is online

Users browsing this forum: No registered users and 8 guests