My Beaut Aussie Cent

[Chris glover]

Bloody Hell!

[Stephen White]

And a rather poor vid of the first stab tests:



Regards

Stephen

[Fabrice Le Roux]

Fantastic R&D program Stephen!

Gyro position is the crux of the matter. If you put it in the turret will it get foxed if you slew the turret? This would preclude adding a second gyro to handle slewing at a later date?

If you emulate the first systems that compensated for elevation but required the gunner to lay the gun manually in azimuth, then the gyro could be mounted in the hull ahead of the CoG to detect and lead the vertical displacement. This arrangement could reduce the need to amplify the displacement, which might induce chatter as every pebble generates a blip. Some sort of "smoothing" either electronic or mechanical might be required.

There might be a risk, and experimentation will prove or disprove this, that any residual bounce due to the simple friction-based suspension dampening of the model, might result in the stab system chasing its tail.

A last thought is that calibration almost needs to be done when the model is finished and at its all-up-weight, as the mass dampening effects then become a "known unknowns"!

Once again you are breaking new ground. Bravo.
regards, Fabrice

[Simon Peck]

Hi Stephen
Super work as always! I haven't seen it myself but the latest Tamiya 1:16 (JGSDF Type 10) claims to have both barrel and turret stabilization. May be worth a look?
Cheers,
Simon

[davidwilkins]

Stephen

I viewed your latest update yesterday but did not comment until now as I was left speechless after seeing what you have achieved, absolutely brilliant work. As I have said before I wish I had just a fraction of your knowledge and skill.

David

[Derek Attree]

Hi Stephen
I have just seen these updates on the gun damping
I have to say its taking things to a super human level.
First class work as always.

Derek

[Roger Sleep]

Hi Stephen,
Haven't commented on your post before, but i must say what a nice job your doing, wish I had the time to do the work and spend the extra time showing others how you do it on the forum really impressed
Regards Rog

[Stephen White]

Thanks for the interest - I hope it's of use and inspires more development. Fabrice, you're spot on - the positioning of the gyro is going to be the crux of the matter. It can't be in the turret as you say. I'm convinced by the logical argument that as a rate sensor, it's not sensitive to distance from the centre of rotation of the hull in the vertical plane but emotion says it should be in the hull mid area. I'll have to do some empirical testing once I get everything finally installed.

One high point today was an envelope from Tony Barton, who makes the most wonderful one sixth cap badges, firearms and head sculpts:

https://sites.google.com/site/antheadssite/

I commissioned Tony to make me some cap badges appropriate for members of the 1st Australian Armoured Regiment and his work is quite amazing. The badges are tiny, less than 3mm in width but the level of detail is extraordinary:







The black beret is so important to the RAAC and RTR that I couldn't not do it, despite the beret not being regularly worn on operations in Vietnam. My one sixth crew will at least be properly dressed on parade.

Thanks Tony.

Stephen

[Stephen White]

I've also been working on one tricky issue with the stab system, EMC in the form of electrical noise interference. The Benedini sound system was picking up and amplifying noise signals from the powerful digital servo I'm using, to the extent that it was really not acceptable.

My first action was to wrap the leads of the elevation and recoil servos around ferrite rings. About as much use as a chocolate ashtray on a motorbike.

I came across EMC first running helicopter programmes for AgustaWestland. I always nodded sagely when the real expert came to see me but have to confess I never really understood more than a gist of what he was saying but I did remember something about power supplies and feedback loops. When in doubt, consult Mark for the best solution. I've run a parallel power supply to the elevation servo, using a cheap BEC which has the added advantage of stepping down 24V to the max voltage which the servo can accept and so delivering more power at a lower amperage.

I constructed a dedicated wiring harness which taps directly from the main battery feed, with a switch to allow the BEC to be switched off together with the Power Supply Module. It is in effect a big Y lead.

At the output side, you have to provide another modified Y lead. On the BEC side, the signal lead is removed so that only power feeds to the servo. On the Rx side, I removed the positive and return leads, so only the signal lead connects to the servo. Something like this:





The BEC itself is a Castle Creations device, relatively cheap and capable:

http://www.castlecreations.com/products/ccbec.html

I switched on not expecting the result - complete elimination of the unwanted feedback, indeed total silence except for the normal whines and wheezes of a digital servo in full song, all of which will be drowned out by Mr Benedini's finest. Result.

Now to finalise the installation. Thanks Mark and my patient colleague at Westlands.

Regards.

Stephen

[Stephen White]

A new crew for 064 and wearing for TankFest, their regimental Black Berets with the badge of the 1st Australian Armoured Regiment:





It's rare to see Australian tank crews in Vietnam wearing any headgear on operations. The baseball cap was perhaps fashionable in some troops and the odd tin helmet is seen stowed but the Black Beret and cap badge is so much a part of the RAAC and the RTR identity that it seemed appropriate to show it. I'm sure my Aussie contacts will approve.

Stephen

[Fabrice Le Roux]

Stephen,

Have a great weekend. I hope your model generates the interest it deserves. Looking great!

Question for your RAAC friends re headgear. At close quarters in the field, did they black up/tape over/remove the cap badge to deprive snipers of a nice aiming mark? Or was this simply not the issue in 'Nam that is was in NW Europe in '44-'45?

Cheers, Fabrice

[Stephen White]

Thanks Fabrice. Short answer is no but your question touches on how the RAAC operated in SVN. They faced a multitude of tactical challenges in a variety of terrain. A popular image of armour in SVN is of assaulting bunkers in close jungle:





In and around the many rubber plantations, the terrain was much more open, as can be seen from these two photos of the assault on Binh Ba in June 1969, one of the major actions in which 064 took part:





Jungle tracks presented a particular challenge, the threat of mines:



Then there was the mud in the rainy seasons:


So the first question I've asked is whether crews operated closed down. The Cent commander was provided with a remote extension to the comd's MG:



I understand it was generally binned, commanders preferring the better situational awareness of being heads up, even during intense assaults. This photo shows CPL Joe Dziedzic and TPR Roger Foote on the start line to assault prepared positions in Binh Ba (note the M79 grenade launcher held by Roger. Note also the US issue flak jacket draped over the comd's hatch. US tin helmets were also seen stowed on the glacis but probably not worn regularly:



Headgear seems to have been a matter of personal choice (and the fashion of the moment). The black beret was always to hand in case a senior officer appeared (here Gen Westmorland congratulating Aussie crews after the Battles of Coral and Balmoral:



The beret was also worn on operations:



Some drivers managed to acquire US helicopter flight helmets or the AFV crewman helmet but these had to be adapted to use the British Larkspur radio fit:



Some troops chose to adopt the US baseball cap, although there are those who turned their Aussie noses up at this element of foreign fashion:



Soldiers adapt quickly and the choice of headgear reflects the challenges faced by the Cent crews in SVN. From my conversations, the two most common considerations were the need for situational awareness and coping with the heat. Operating a tank heads out is not for the faint hearted, nor is firing the commander's MG from a very exposed position. Perhaps the combination of heat and relative blindness determined how crews operated. The Black Beret represents something more than fashion though and that's why I've gone to some lengths to show it on 064.

Hope that's of interest.

Stephen

[Stephen White]

No sooner had I pressed send than up popped an email from Rip Riley (who commanded 064 as a troop sergeant during A Sqn's tour in 1970. In part, he says:

Fabrice's question about the subject matter was interesting to say the least.
In The RVN I never saw the badge taped over, not that the black beret was often the head covering of choice outside the wire.
Most of the lads kept their berets close to hand for wearing in the advent of a senior commander's visit.
Those chaps were entitled to a real RAAC salute if the tactical situation was acceptable.
There is a great photo kicking around of US General Westmoreland congratulating a tank crew in the field after Coral/Balmoral; baggy jungle green trousers, black berets and silver badges and totally naked top halves.
I recall one night sitting in my commander's slot during ambush watch wearing my beret when I realised that the moonlight would be reflecting off the shiny badge.
Falatism saw me skewing the beret ninety degrees to the left; the beret adopting the classic British sports car driver's position.

Rip commanded 064 during Operation HAMMERSLEY, in Feb/Mar 1970. HAMMERSLEY involved operations by 8RAR and A Sqn, amongst others. The initial operation was a simple force protection task involving sappers using a quarry to provide building material. The quarry was close to the Long Hai Hills, which contained a VC sanctuary known to the occupying D445 battalion VC as the Minh Dam Secret Zone. Once the Australians became aware of the opportunity to take on D445, a series of ambushes culminated in a deliberate assault into the positions and an abortive B52 strike. Such was the threat that in this atmospheric picture, 8 RAR diggers are, unusually, wearing flak jackets and helmets.



A vivid account of the operation is here:

http://www.taylor.id.au/charlie.htm

Regards

Stephen

[Stephen White]

I've also just heard from Lt Col Bruce Cameron, who was a troop leader towards the end of the Australian time in RVN. He says:

Fabrice is right to ask about snipers ... beret badges weren't the aiming points, however. If the enemy were firing small arms, then 'centre of the seen mass', was most likely the 'target'. The Comd of the Heavy Weapons Coy, 3 Bn, 33 NVA engaged me from directly in front... his AK47 burst hit the barrel jacket of my comd's .30cal

Fabrice is right ... there was a great difference between 'NW Europe '44-'45' and Vietnam ... when tanks assualted bunkers, they were doing so in close jungle, the range of engagement was about 20m.


This illustrates the difficult balance between protecting yourself and operating heads out to maximise awareness and allow the commander's MG to be brought to bear. Food for thought on what the Australian Cent crews achieved in RVN.

Regards

Stephen

[Stephen White]

After weeks of developing the stab system, with more work to do, it's a real pleasure to get back to metal bashing, to things you can touch, smell and hit with a mallet.

The production track guards were of little use in Vietnam and the Australian crews quickly discovered their vulnerability to damage from what they called scrub bashing and from mines:



In June 1969, after trials, a modification instruction was issued to replace the tin work with quarter inch thick steel carbon steel plate (copy via Mike Cecil):



These were simply, almost crudely made assemblies implemented by 106 Field Workshop. The front, inter front, inter rear and rear panels were replaced and steel plate was welded over the track guards on which the bins were mounted. The outside edges of the plates were reinforced with 2" x 2" mild steel angle and reinforcing plates were added where required.

This is 064 with the Vietnam guards:







Paul Scott's tank is one of very few with the surviving Vietnam guards and he's very kindly provided photos and measurements to allow them to be re-created in one sixth. I've decided to recreate 064 at the mid point in her time in Vietnam, October 1969, by when the modified track guards were fitted.




















Using the aluminium brazing technique, the assembly begins with the forward track guard brackets, with reinforcing plates:





Regards

Stephen