Jerry and the M3

Forum for discussion relating to the M3 Lee nd Grant Medium Tank
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Adrian Harris
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Re: Jerry and the M3

Post by Adrian Harris »

Nice work Jerry, though I do wonder how big a lump of metal you started out with when making the JerryScope (great name :D ) ?

One very slight niggle is that, according to a recent discussion on the G104 list, the M3 didn't use the bent pin on the fuel caps, just the original shorter straight version.

Once I get out of house clearing hell I'll be glad to get back to the M3.

Adrian.
Contact me at sales@armortekaddict.uk for details of my smoker fan control module and other electronic gadgetry

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Jerry Carducci
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Re: Jerry and the M3

Post by Jerry Carducci »

Adrian, thanks!

I was not ambitious enough to make a pattern and cast a part in aluminium at least to get started however that probably would have been more
efficient. I began with a small scrap piece of ~16mm aluminum plate I have. If any of you are familiar with IBM 3890 check reader-sorters...that's
where the aluminium came from. When I was on software support team for the check processing system I had a good relationship with the IBM CEs
from whom I ultimately purchased all their scrap aluminum parts; these plates came from a major refit. I intended most of the metal for melting;
many of the parts I've cast or machined are from 're-purposed' aluminum sorter parts.....I'll likely never run out of aluminium for casting. I likely have over 350kg of it...

With regards to the pins thanks, I might try straightening and shortening them or just chalk it up to my go to explanation: "...these particular parts were made by a later sub contractor who worked from a different set of prints that were smudged with a coffee stain".

Jerry
http://tanks.linite.com/ - RC tanks: stay home, build a tank and save a life!

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Jerry Carducci
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Re: Jerry and the M3

Post by Jerry Carducci »

A few more little bits added to the Lee. The brace/strut/hold open whatever its named for the from driver's hatch. It was a challenge to make
such a small articulated swivel_able joint on this thing all from steel; not being certain how the original is made. Also the retainer clip is functional
actually riveted to the hatch with two tiny pins. I've decided I'll remake the front ProtectoScope at some point as the drum carrying the prismatic optics is probably twice the diameter of what I chose but this will do for the moment.

Also mounted is the antenna base purchased from ECA. I wanted to make a pattern and cast in bronze but laziness overtook me.

I have a couple of small things to attach, the ECA tail lights being one and then hopefully it's on to priming the rest of the model then final paint;
all contingent on if this confounded, infernal, incessant wind will stop long enough to allow it. These past two months have been the windiest I'm
able to remember. The wind begins early afternoon and blows fiercely until late at night.....

After priming I will mount all the special effects hardware and electronics and give it all a good shakedown... then a wipe down and paint. fingers and
toes crossed...

Jerry
Attachments
support in use
support in use
support stowed
support stowed
Antenna base pot- antenna to be added.
Antenna base pot- antenna to be added.
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Jerry Carducci
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Re: Jerry and the M3

Post by Jerry Carducci »

Ah I forgot to mention that I had a chance to make some latches for the side hatches/ doors. The two bolts holding the hasp on the outside made for a convenient way to attach the latches.. the only touchy part was drilling for and tapping a 00-90 screw blind hole in the door to attach the handle pivot point... The latches door securely close the doors; it's entirely possible I could find myself locked out of the model after running except that I can reach down from the loader's hatch and unlock the door. Apologies for the sideways photo...

Jerry
Attachments
door latch02.jpg
door latch01.jpg
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Robert E Morey
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Re: Jerry and the M3

Post by Robert E Morey »

Looking good - nice looking details Jerry!
Best regards,
Bob

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Jerry Carducci
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Re: Jerry and the M3

Post by Jerry Carducci »

I've made yet more progress. Applied most of the OD top coat however final touch-ups (of which there are many) yet need to be done.
Placed all the components I plan to implement, power, sound and recoil as well as having all the control surface interfaces/ servos.
I'm plagued by a improper battery for my pre-2019 Taranis transmitter so I'm waiting for more appropriate packs for it before proceeding further.

As I came late to the recoil system party for this model I was able to purchase many of the bits needed but had to make even more to fully
flesh out the controls. I made threaded connectors for the breech end of the 75 and 37mm gun tubes to allow attaching servos and my own servo mount for the 37mm recoil. Now to work out all the connections - I assume some are direct connections to the receiver. Not certain I've synchronized the sounds to the functions properly so that will be an ongoing effort however the 3 position switch selection seems to work. In work with a Benedini mini I found a clever way to mix a pot and a toggle (two position) switch to select sounds and lights although not sure that technique would work here; basically dividing a pot into whatever number of divisions that correspond to the number of selections available which are selected in turn by the two position switch. Sort of a built-in rotary switch. I may test a copy of this model profile sometime when I'm feeling adventurous and have nothing better to do...

I did have some trouble with the pulley for the commander's cupola scraping on the turret ceiling and faced with the choice of machining a recess on the turret or making the pulley smaller I chose the latter including a relief to minimize any potential contact surface.

I have a commander figure picked out, I'll wait on introducing him to a later date..

I've included a few photos of my progress. Also a video reference of a brief run test.



Be well all.

Jerry
Attachments
IMG_5730.jpg
IMG_5729.jpg
IMG_5721.jpg
IMG_5720.jpg
IMG_5719.jpg
64409571145__76F2A8CE-EF4E-4E5D-836D-DC6F5D5E6A2A.jpg
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Jerry Carducci
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Re: Jerry and the M3

Post by Jerry Carducci »

Continued progress. While waiting for real batteries for my Taranis I modified an existing 11.1v pack with an appropriate JST connector and it made
a world of diference although I had to temporarily 'Jerry rig' ( I'm comfortable with that description!) the back of the transmitter case as the pack is slightly too large. At least I didn't resort to duct tape or chewing gum and pipe cleaners.....

I have most major functions implemented except for the following:

- traverse on the 75mm casemate -servo works but doesn't seem to want to rotate the drum even though the drum moves quite easily by hand
so I'm still looking at that. May be a simple case of insufficient leverage.

- Elevation of the small cupola mg - only because I ran out of channels. Not sure if s-bus will help here but I'll look into it. at present I'm using fully 8 channels to control everything.

Recoil is working but rather in the form of an 'anti recoil' - the gun tubes jump forward and go back into battery- I'm assuming this can be corrected by moving the interface connection 180 degrees on the servo horn. Also I have yet to separate both the 37mm and 75 from simultaneously recoiling; again not sure if that is normal behavior. MG Led and gun flash work, more or less but need to be fixed in place, mounted

Wiring is quite busy in the model! I think I'll change the connector type for the cupola drive motor- the small blade connectors work ok but are rather not my choice.

I need to revisit the exhaust pots of the model- I'm assuming as exhaust orifices they should be all rusty and nasty looking as opposed to clean and pristine as they are at the moment. Touch up and tactical markings to follow. A battery mount is in progress. But I'm first going to take a little break from this model....

At some point I'll post a video of the model running in actual California dirt. I've also considered taking it with me one of my volunteer days as there are quite a few open areas in the vicinity which also have real California dirt. I volunteer aboard the USS Hornet museum as a member of the Aircraft Restoration Group; I'm current working on the restoration of an F4 Phantom- I get to rebuild some of the air brake/ flaps that have corroded. We are finishing up an S2 Tracker and prior to that we worked on my F8 Crusader- one of only a few A models in existence. I say 'mine' as the plane is assigned to me as plane 'captain'- I'm responsible for the restoration we did (I did a lot of metal work on the old girl) and its ongoing maintenance.
Before anyone asks: no I was never in the service and no I'd never worked on aircraft before dipping my toes in it on the Hornet- it's so cool to be part of living history there! My first love is and always will be armor...

Looking forward to the arrival of my Easy 8! A great companion piece to my M3.

Be well,

Jerry
http://tanks.linite.com/ - RC tanks: stay home, build a tank and save a life!

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