Ryan's M3 medium

[cantankrs]

Yep, I agree. The pair of engine floor inspection plates seem to be present too. All very nice. That weight is interesting to know. Course the cone shaped dome on the back of the gearbox is the handbrake. The tailshaft with the sprockets welded to it has the right looking unijoint for Grant too - I think its Mack, like the gearbox, whereas the diff/final drive assy probably has a Chrysler plate on it? Any track joints that are 'kinked the wrong way' are known as 'dead' - I think it just means the track pin with the rubber donuts has managed to twist in the tube that forms the track frame (don't know if the donuts shear or if they slip in the tube, or both). I don't think you can go very fast with dead shoes - I presume there's a big risk of a track breaking and high risk to anyone nearby along with colateral damage. I have a Stuart manual that shows the track pins with donuts being pressed into the track frame under high pressure after being dunked in castor oil (caster oil being non-harmful to rubber - I think it's what brake part grease is made from). The pins have the flats machined in them for the connector wedges and thus the pins are held by a jig in a certain orientation so when they're pressed into the track frame they are slightly angled and when the track is assembled it has a tendency to curl inwards thus creating 'live track'. That type of steel 'pad' consists of two halves, outer and inner. Outer has the 'tread' and both may be plug welded together. Also that steel track probably has 1/16 or 1/8" (I can't remember) thicker diameter pins than the rubber track on your first M3 Medium. The sprockets are the same so the connectors are bored out I think.

Regards

Alex

[anthony urek]

Ripper pics Ryno, job well done. What is the heaviest the crane can lift?
Just shows you how effective tracks are for grip. But watching a WWII doco last night they showed a Sherman sliding down a road sideways on an icey day.

[Bob Moseley (RIP)]

OH NO!! Throw the tank away. That is as bad as having a full ashtray in a car. The tank is stuffed.

Bob

[Ganmain Tony]

Well done with the tracks old boy..... amazing what can be achieved by just saying 'bugger it' and adhering to Murphy's law....

"If it jams..force it. If it breaks, it needed replacing anyway"

Have you got any pictures of the current donk and transmission set up in the one that goes??

Just very interested to have a look..

Has anyone got any pictures of what was originally in these beasts??

Twin GM and Radial set ups??

One last question - did the Australian Sentinel use the same Chassis set up as the M3??

[cantankrs]

Anthony Urek's current thread has the picture below (the last pic) posted by 'Roy206' of a 6046 power pack. Also in the thread is the same chap's link to their running 6046
Note that there were other combinations of GM 6-71's such as a few pics I've gathered from eBay over the years of GM powerpack configurations for various applications.
Also, here in Western Australia is a fairly legendary primemover or tractor truck built after the war to haul iron ore to port named the Rhodes Ridley and it has a twin powerpack from an M3 Medium along with a gearbox and I think they used the crown wheels and pinions in specially cast diff housings. Click the link to visit their website.
And for Tony regarding the Sentinel, while it was based on M3 Medium drivetrain and tracks, the AC1 employed 3 x Cadillac SideValve V8's. Two other engine configurations tested was the 3 x V8 blocks mounted onto a welded steel common central case something like the Chrysler Multibank; and then 3 x Gypsy Major (I think it was) aircooled inline aero engines in the intial clover leaf layout. The thing was that Australia seemed to not have the machinetools to produce helical gears so they developed a straight-cut geared variation of the M3 box. Bradford Kendal I believe cast the hull and diff housings and turret. Only recently I found that the floor appears to be 3 x flat steel plates bolted into the hull casting, for each the driving, fighting and engine compartments - happy to hear more about this from anyone..?
I note that the French Somua S35 appears to have been a major earlier achievement in being cast as a 2 piece lower hull, 2 longitudinal plate floors, 2 piece upper hull and turret. While BK took the Sentinal's castings further by employing one main casting for the hull (except the diff housing and floors as noted).
Alex

[Ryan]

Hi Tony, the cranes max lift was 28tons according to its hook.

Cheers Bob, thought I'd throw a curly one in.

Ganmain T, here's some pics of the set up. It's a MAN truck engine of 15.2lt, v8 and 300hp. And hey.....you know of a Sentinel do ya??? Check out my Sentinel thread here: http://www.mapleleafup.net/forums/sh...ad.php?t=11517

And cheers for the ID Luke, Adrain and Alex. Here's a close up of one of the suspect track links too.

[Ganmain Tony]

Vast knowledge Ryan that comes from Wikipedia.....

Very interested in all this stuff - always have been. Built all the models when I was a kid, etc etc...

Great powerplant!! Youve just gotta move it to the back...

Would be an awesome start to building a replica Sentinel. They look manificent in pictures with the 17 pounder.

Speculation of course but I reckon they would've done a better job than the Sherman.

Figure wise, on paper they add up. Low profile, sloped armour, very quick (for the day) well armed (with the 17 pounder). The yanks couldve tooled up for this design.... surely.

I vote for building replica Sentinel - but then, it aint my money.

[Ganmain Tony]

Originally Posted by cantankrs

And for Tony regarding the Sentinel, while it was based on M3 Medium drivetrain and tracks, the AC1 employed 3 x Cadillac SideValve V8's. Two other engine configurations tested was the 3 x V8 blocks mounted onto a welded steel common central case something like the Chrysler Multibank; and then 3 x Gypsy Major (I think it was) aircooled inline aero engines in the intial clover leaf layout. The thing was that Australia seemed to not have the machinetools to produce helical gears so they developed a straight-cut geared variation of the M3 box. Bradford Kendal I believe cast the hull and diff housings and turret. While BK took the Sentinal's castings further by employing one main casting for the hull (except the diff housing and floors as noted).
Alex

Alex seems like I need to back up here before I upset anyone.....My comments about the Sentinel were an attempt to open a debate about Ryans restoration...not so I could jibber on attempting to impress everyone with how little I know....and believe me, my knowledge in this area is very little.

I thought (wrongly it seems) the M3 bottom half was identical to the Sentinel based on what you mention above. So opening a debate about altering the M3 to a Sentinel is now a non debate.

But i would seek some clarification on the differences. The hulls to me look the same, why isnt it possible for Ryan to do a Sentinel look alike?

[Ryan]

Originally Posted by Ganmain Tony

The hulls to me look the same, why isnt it possible for Ryan to do a Sentinel look alike?

My quick observations Tony are that the bogies have a slightly different Layout. The rear idler sits at a lower position and the transmission/final drive housing is slightly different.
But in saying that...if Stephen Speilburg can make a Tiger Tank out of a T-34 and put it in a movie anything is posible.
Some sheetmetal could make the bogies look similar I think, while the upper hull, being started from scratch could be made to look identical.
People make PzIII's out of FV432 APCs so a Sentinel out of a M3 Grant is quite possible.
Ryan

[anthony urek]

Originally Posted by Ganmain Tony

Has anyone got any pictures of what was originally in these beasts??

Twin GM and Radial set ups??

Here are some pics(although crappy) of Grant engine bays one with the 6-71 and the radial. The twin diesel one has one engine only. Runs fine on one. One engine was typically removed on cut down Grant dozers to save weight and fuel. Unfortunately the motor is covered with tarps to keep the water out which makes it hard to see. But you can see how tight the fit is! No room for maintenance or repair. You can see the fuel tank on the side wall of the engine bay along with the water and oil tank all incorporated into one.
The twin diesels are a great engine(s) but two of them are just too heavy. The radial is more than half the weight of the 6046 twin pack. And I have been told by a man who has driven both that he could pull a higher gear up a hill with the petrol radial. What a motor! I have included a pick of whats inside the radial, simplicity at its best!

[Luke R]

Correct me if im wrong, but didn't the M3 stuart use the 670 and the M3 Lee/Grant petrols the R975 Continentals?

[anthony urek]

Yep my mistake, Ill fix it.