RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

[Jofaur86]

just for information

http://indochine-images.blogspot.com/20 ... chars.html

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[lmcq11]

just for information

Thanks, i just purchased a copy of this rare 400 page book last week, it is on transit from France. It seems to be the only book that tells the whole story of the 10 Chaffee tanks during the siege. It is a signed 1995 copy by the author, Andre Mengelle, who volunteered to jump over Dien Bien Phu in the middle of the battle to take over the command of "Conti" when Yves Hervouet was seriously wounded. I'll be modelling his tank and i hope to do a good job. I will provide more insight when the book arrives.

[lmcq11]

Thank you Kaczor, Model Builder 4, Barry and Eric for you encouragements.

The next two posts are for the main suspension and roadwheels.

I want an M-24 that looks like an M-24 from up close. Creating my own chassis was a must but it involves a lot of work, risks and potential mistakes at every corner. Because of the RC suspension is technical and must use items available on the market (durability, availability of spare parts, cheap...), some compromise are also required.

Seen here are the M-24 suspension hubs that need to be created. It involves some complexity because the side armored plate are not strait. The suspension arms have a specific shape and length. How it comes together is unique to this tank, every millimetre makes a big difference. The idea is to do something close, but adapted to RC components that are the closest match.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

First tasks is to create the suspension hubs. Basic shapes and components are created.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The positioning of the suspension arms need to account for the length and thickness of the suspension arms, the size of the roadwheel, height, space between roadwheel, placement of the dampers, distance between the tracks and the hull, etc. It took me a couple of hours to do calculations and make decisions on the positions, but also shape and thickness of every parts, etc. Adaptation and compromises are required to make the integration work.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Hubs are positioned carefully, every half millimeter makes a difference.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The suspensions arms are prepared. An assembly chain was created to rework all the 20 roadwheels according to the prototype shown early.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Roadwheel 1, 2, 4 and 5 have a damper and that is what makes the suspension for those wheels. However, road wheel number 3 does not have a damper. I thought about giving no 3 a torsion blade suspension but i had difficulty creating a system that will hold the suspension arms in place with the torsion blade using the HL suspension arms.

So, i opted instead to move the damper inside the hull like i have done in past builds. A shaft extension is created that connects the external suspension arm to another arm inside the hull linked to the damper. The main shaft is in thick brass and goes through an aluminum tube so that it does not get into contact with the softer plastic when operating.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The two suspension arms of roadwheel no 3 are positioned with their shafts, requiring digging into the 4mm base of the chassis. Use of a torsion suspension would not have made it easier.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Each suspension arm is locked to the shaft with an M1.2 steel bolt going all the way across the plastic and through the shaft.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

It took about two hours but roadwheel number 3 now have a working suspension, and nothing shows externally to make it inaccurate.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The internal dampers are given anchor points at the proper location to activate the suspension like if it was outside.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

continuing on following post

[lmcq11]

Overview of the hull with its main suspension. I had to put the dampers a bit more strait than i wanted compared to the M-24. If i gave the damper the same angles as the real ones on the M24, the RC suspension was becoming inefficient.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Because of the weight of the gearbox at the front and also because the tracks will be pretty tight, I gave roadwheel 1 and 5 a stronger metal damper with harder spring. It will be less smooth when hitting an obstacle, but the hull will show correctly.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The reworked road wheels are installed. At this point, everything if pretty rough, i did not polished anything. The gearbox was simply thrown inside to give the hull some weight.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Alignment and solidity are critical.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Notice the thinner roadwheels compared to regular M41A3 or M26 roadwheels. A lot of efforts went into this. The resizing of roadwheels is recommended only to experienced modellers.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

View under the chassis.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Next steps, installing the gearbox, sprocket, return rollers and idlers.

Regards, Louis

[Raminator]

Taking your builds to the next level, Louis! I think fully scratchbuilding your own chassis was pretty much the only progression you could make from Chris Ludwig's kits.

Some very elegant but simple engineering solutions with the running gear, impressive as always.

[lmcq11]

Thank you Raminator for your encouragement, as always. Building the main body of the M24 chassis itself was simple, and no interlocking joints to fill... However, each panels of the chassis has an angle, which complicates every item that needs to be created and attached to them. I have to build the angle. It is taking a lot more time than if the chassis had strait panels.

Continuing with the build

Installation of the gearbox was simple. However, the planned Mato gearbox on inventory that i like to always use on my builds did not fit. The shaft on the Mato Panzer III gearbox were too short, and the Mato Panther gearbox was too high. I did not want to bastardize these expensive gearbox by mixing components. After going through all my available gearbox in the scrap yard reserve, i selected what seems to be a pretty good Heng Long Panther gearbox with steel gears. Only the tip was too close to the rim for comfort as you can see. Some filing with the Dremel resolved the issue in no time.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Measurements were carefully taken to place the gearbox at the right location, as far forward as possible, at the right height and with the sprocket shafts coming out at the right length. I had to squeeze the two gearbox as much as possible. They are mounted on a plasticard plate 4mm higher than the bottom of the hull and solidly held with M3 screws going all the way through. I had to create new mounting holes on the gearbox for the screws to be at the right location.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Looks like the shape of these gearbox were made for the M24. Mato metal M4A3 sprockets were used for the testing as i am modifying these for the M24.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

As is usually required on such build, the front inside panel had to be grinded on the inside to provide the maximum space for the gearbox to be placed as forward as possible.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

View of the M24 Chaffee sprocket. It is very similar to a Sherman but with closed teeth.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The metal Mato M4A3 Sherman sprocket are designed for the Heng Long model and has opened teeth. I could have lived with these but i want to do the best i can on this build. Those teeth holes can be filled. I also removed the 3 inner brackets that provided a base for the cover, not to be used here.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

To fill most of the void space and provide a good base for the filling, a 1.5mm plasticard part was created to fit inside, then drowned in superglue.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

While the superglue is still liquid, nail files are used to file the whole surface smooth, including the bolt heads. It creates the best filler i know, superglue mixed with plasticard and metal dust. After 5 minutes of sanding and 3 nail files for each, the surface is smooth and solid. The rim is then cut along the metal inner hole with a blade. A round plasticard plate with bolt heads are created to simulate the attachment at the bottom.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Meng bolt heads are put on the sprocket surface and the M24 sprockets are ready. I only did the outer side of the sprocket because the inner side is not visible and it would be a wasted effort.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The M24 sprockets are installed and looking good. Not perfect because it is metal and there is so much we can do with these but this is satisfactory when compared to the real thing.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Continuing on following post

[lmcq11]

This is the M24 idler. Notice that it looks like a regular roadwheel but different in structure, without rubber band and with holes to make it lighter. Its complicated to accurately reproduce because the material is quite thin.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The best i could do is to take the M26 idler and remove the rubber band and make it thinner. It is not possible to make it more thin without breaking the structure of the wheel. The inner section of a Mato Sherman idler adjuster is used. The ball bearings were put on the plastic idler wheel.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The idler wheels are ready.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

View of the M24 base for the idlers.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The base is replicated but as this is RC, the rest of the complicated idler components are not put on. There are mostly hidden behind the idler anyway.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

A 2mm spacer was added to align the idler with the roadwheels. Not perfect but this idler/track adjuster is a lot more realistic than most sold on the market for the various tanks.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

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View of the M24 idler on the model. I am noticing that the Meng bolt heads on them should be bigger. I will take care of that.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

View of the idler mount inside the chassis. I gave them an extra 8mm of plasticard thickness for the base, giving a total of 14mm of plasticard thickness for the idler adjuster bolt. It should be more than enough to keep them in place, solid and aligned.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

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That's it for now. Next step, the sprocket gearbox, return rollers and the stop dampers for the roadwheels.

Regards, Louis

[jee]

awesome built again, and as said before, all the historical info makes it very interesting to follow!

[lmcq11]

Thanks Jee

Looking at the front lower panel, the M24 has large sprocket hubs.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

I decided to build these using solid 4mm plasticard in 2 separate sections (frontal and sides) coming together at the front. Plasticard layers are glued together and then carved with the Dremel in a slow telescopic fashion, adapting the parts to the various angles of the hull on all sides. Grinding a bit here, a bit more there, until they seem about right. The superglued and sanded smooth, superglue being used as filler on all joints.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The side bolted plates are done separately as they are technically removable, the separation must show.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Here are the finished sprocket hubs.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The return roller mounts and roller as seen on the Bronco 1/35 kit.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

For the return roller mounts, i took an old M41 chassis in the scrapyard and cut the 6 mounts with the Dremel to provide raw material for the M24 roller mounts. Because the M24 has an angle on the side armor, i am again forced to manage angles.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

I added the side reinforcements and some details. At this point, they are longer than they should. They will be cut at the right length once the return roller wheel in put on and exact calculations can be made.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The return roller mounts are installed and then cut to the right length on the exterior end.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Continuing on following post

[lmcq11]

The return rollers are prepared but not reduced in size as much as planned. They would have been too weak.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Return rollers are installed.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

I did not polish the rubber rims.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

On the M24, the return rollers are higher than the sprockets and idlers. They are properly aligned, something to watch for on such scratch build model where everything bad and wrong can happen at every step.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

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A few words on the references used on this build.

The Squadron Signal Walk around book on the M24 is a must have for this build. Contains tons of color pictures, explanation graphics, painting guides and is well explained.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The WWP book on the M24 is ok but there are gaps in the walk around set of pictures, requiring the modeller to look elsewhere for specific areas of the tank. Strangely, half the book is focussed on the interior and the engine compartment. I am aware of the Verlinden 1/35 engine compartment that would make engine pictures relevant, but i do not see how all the other pictures of the interior can be of use to most buyers unless the modeller scratch build it all.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

For a complete battle history of the ten M24 Chaffee at Dien Bien Phu, the book "Des Chars et des Hommes" by Andre Mengelle is the only one i know. It is in French and is quite rare. It contains 400 pages, with some picture sections and maps. Sadly, I have not found an English edition available for those who can't read French. I have read about half so far. It is a well written and fascinating book, written by someone who was there during half the battle. The author uses rich language, describes the daily battles of each tank in details, but also describes the men, their emotions, their friendship, their sacrifice, the hardship, the terror of the bombardments. When most officers were either dead or wounded, he volunteered to jump over Dien Bien Phu to take over a tank, and eventually the command of the tank section. His parachute jump at night over Dien Bien Phu is memorable. It is highly recommended.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

I purchased the book on eBay from France. The seller told me it belonged to a veteran of the 1st RCP (1er Régiment de Chasseurs Parachutistes) who fought in Indochina and Algeria. He recently passed away and the widow ask him to sell it. The book is dedicated to this paratrooper veteran and signed by the author, Andre Mengelle, thanking him for his interest on this dark chapter of French history.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

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The fact that Andre Mengelle was the second commander of the tank "Conti" at Dien Bien Phu is a direct connection to this M24 build because it is the tank i have chosen to build. Seen here is a view of Conti long after the battle, a wreck on the battlefield. I was not really surprised that there are so few pictures and films of the battle from the French side. The famous film director Pierre Schoendoerffer who created so many war movies on the French Foreign Legion was there the whole time but apparently, the Viet Minh confiscated all his precious material when the garrison surrendered. After so many years, it would be interesting and tremendously appreciated for the Vietnamese to release this material if it still exists in some archives somewhere, likely in Russia. But pretty sure he must have searched for it before he passed away in 2012.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

The author, Andre Mengelle, next to his tank Conti during a visit of Dien Bien Phu in 1994, forty years later. It must have been quite an emotional moment.

RC 1/16 M-24 Chaffee light tank- Dien Bien Phu 1954 - Build

Next step, the stop dampers and the upper hull.

Regards, Louis