1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

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lmcq11
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1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by lmcq11 »

Hi, my turn to build the Puma.

As i am waiting for parts for the GTK Boxer build, i will slowly start this one.

The Sd.Kfz. 234 (Sonderkraftfahrzeug 234) was a family of German WW2 armoured cars. Coming in 4 main versions, the vehicles were lightly armoured, armed with a 20, 50 or 75 mm main gun. This is the 234/2 Puma with the 50mm turreted gun.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
Capture2.JPG (46.59 KiB) Viewed 3328 times
This is the Metal Origin kit inaugurating my brand new retirement verandah modelling workbench. A modeller's paradise with sunlight for my eyes and summer breeze for my lungs. The kit is the special edition with metal ball bearings and servo holder (mandatory). At 378 eu for me in Canada (no VAT) from RC-Panzer-shop.de with 25 eu shipping, the basic kit is a good deal considering the metal components. I plan on providing my own solution for control board, rotation, recoil, etc.

I have browsed through a few builds of this model on the web. I have rarely seen a kit generating so much negative emotions, with builds sometime taking years, totally redesigned or being abandoned. I have no wish to replicate any of the stuff i have seen so i will build it my way. At this point, the plan is to build it strait from the box using Metal Origin parts and avoid any pitfall. This vehicle is to drive around, not a crawler for mountain climbing.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
The instructions are good and assembly goes fast.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
This is the dreaded Metal Origin custom gearbox. Of course, steel gears would be better. I somehow do not find it too bad myself. It should do the job with careful assembly and use. The availability of spare parts is my main concern for the future.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
The gears are pretty loose, with makes it simpler for the builder. The very tight gears that i am using on the GTK build required a lot more attention and more tricky to fine tune.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
Everything is falling in place. I was honestly expecting a lot more trouble. All good so far. I think the newer versions of this kit are likely better than the first ones.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
The seller at rc-panzer-shop.de made me buy this optional set of upgraded swing arms (left), telling me that these are required unless i build a static kit. To my surprise, the kit contains pretty good basic drive shafts (right) that are regular dog bones with drive cups that would have done the job with some grinding and filing.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
We'll see if these cardan joints are worth the 81 Euro (Vat free) I paid for them. In any cases, i now have a set of spare shafts. They are interchangeable.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
I have seen a few pitfalls to avoid.

First, this plastic part can be put upside down. The side matching the ball is actually the smaller one. If put on the wrong side like I initially did, the steering is quite hard, while quite loose if correctly put.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
The ball bearing needs to be hammered fully into place at the bottom of the arm. Careful not to destroy the bearing in the process.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
continuing on following post
Last edited by lmcq11 on Mon Jun 07, 2021 5:57 pm, edited 7 times in total.
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lmcq11
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by lmcq11 »

Not sure if it is because of the optional swing arms but the suspension on first test was quite jumpy. I had to file with a hand file the bottom of each drive cups to give more room for the dogbone shaft pins. Don't forget to put in the provided rubber rim inside. The suspension runs better once some weight is put on it.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
Those hex nuts need to be carefully inserted into the gears as it is possible to make them go in slightly sideways without noticing it and damage the gear if forced in.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
I have installed the pinion gear on the 540 motor as far deep as can be.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
Experience with the TPZ-1 Fuchs build last year taught me that a steering servo on a multi steering axles vehicle need to be as powerful as can be. Optimally, each axle should have its own servo. The design of this kit is having all four axles on one servo... Space is limited. Let's go with this design for now but let’s find the most powerful regular size servo available. I have purchased this nice 35kg servo on Amazon. Much better that the less than 20 Kg given by regular servos. Not sure the torque of a 20kg servo would work well. Testing is promising but the real test will be with the tires on. This bitch will turn.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
Those 3 washers indicated on the revised instructions are absolutely required to elevate the servo platform and clear the steering arm below. The servo end points need to be reduced to about 30% on both ends. Otherwise, this powerful servo might damage the metal mount and steering rods.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
The 2 connectors on top of each other that links the servo to the main steering rods need to be grinded in order to clear the motor above it.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
Every screw on the steering bars everywhere need to be loose, they cannot be firmly screwed, otherwise the steering is too tight. A drop of superglue on the tip of the screws going inside will keep them in place, while still being able to be removed if need be.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
Overview of the chassis in the sunlight.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
continuing on following post
Last edited by lmcq11 on Wed Jun 23, 2021 1:18 pm, edited 7 times in total.
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lmcq11
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by lmcq11 »

The main gearbox was half filled with synthetic grease gel and all the four drive shaft gearbox and axles are drowning in it. It helps reduce the gear noise as well. It’s running smoother than expected after all the comments I have seen. Again, the real test will be in the field.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
I find the provided plastic/metal steering tie rods to be too large and really ugly. These are not true steering tie rods. It would be nice to replace them with better ones in full metal from China that are more easy to adjust. I'll see later about that.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
A nice touch from Metal Origin.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
The motor should be installed before the steering servo. But be ready to put them on and off at least 5 times as you finetune the drive train.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
Every millimetre is counted on this chassis. There is not much room for improvisation or design change. I find the design to be pretty good. Not sure why all the negative comments I have seen.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
This is a really nice, beautiful and exciting chassis. I recommend cleaning the metal parts with a polishing hand file to make them shine and clean. I recommend avoiding painting any moving metal parts.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
continuing on following post
Last edited by lmcq11 on Mon Jun 07, 2021 6:01 pm, edited 6 times in total.
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lmcq11
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by lmcq11 »

This is it for now. The build is going well so far.
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
1/16 RC Sd.Kfz. 234/2 Puma armored car - build
And here is a short video of the steering, motor and gearbox in test. Keep in mind the whole thing is not yet finetuned.

phpBB [video]


Regards, Louis
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lmcq11
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by lmcq11 »

Short video of the first field trial outside on uneven pool deck made of cement. Everything is looking good out of the box, no issues. The gears and drive shafts are still a bit stiff but getting better as they get some mileage. The 8x8 steering is surprisingly excellent. The wheels are turning perfectly on cement even when the vehicle is fully stopped. That 35kg servo is making a difference.

phpBB [video]


Regards, Louis
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by BarryC »

:clap: :clap:

Another outstanding build in progress Louis! :thumbup: :thumbup:

Barry
"Details make perfection, and perfection is not a detail."
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by Herr Dr. Professor »

Louis: I am following your build closely. I bought a complete Puma kit about two years ago, and I have read scary things about making them run and steer. 8O I am grateful for great detail you are offering in your build here, for such detail will help me when I work up the courage to start.
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by lmcq11 »

Thank you Barry and Herr Professor,

After initial study of the basic kit and design, i concluded that the best option is to make it work with what is provided. Everything is designed so tightly inside the hull, if something is changed and the replacement is a bit bigger or of a different shape than the original component, then the whole basic design falls apart and everything needs to be redesigned. There is 1mm between the motor and the steering servo behind it. All the pull rods run just under and around them. The hull is very narrow and long. Almost everything is in metal, difficult to modify. I was in no mood to be too creative with this one with the basic tools that i have.

For this build, skills and understanding of automotive mechanics are more important than others. I could see right away that all the slots on the drive cups were too tight and making the suspension jumpy when turned by hand. They just needed some filing with hand files in order for the dogbone shaft to run more smoothly and give a break to the gearbox. The motor is strong and i can see that damage to the gearbox is possible if everything is too tight and the builder is turning on the power to see what will happen...

Same thing for the steering. If you screw all the screws of the steering tie rods solidly in place so that they don't fall, then nothing will steer because the provided tie rods are not steering rods... They are suspension tie rods. The plastic ends do not provide enough flexibility to make the ball swivel without resistance. It is also very difficult to adjust the wheels to make all eight of them strait because one end of the tie rod needs to be disconnected in order to adjust the length, at every time. They work now by keeping them loose on both ends but i have a set of real metal steering rods on order to try to replace them. A standard servo is also not strong enough for the design.

I am currently working on the turret rotation. I determined that the Metal Origin turret rotation optional set was looking weak and way too expensive. For this one, I will try to design my own.

Regards, Louis
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by Raminator »

Moving ahead smoothly Louis, I can tell that your meticulous and methodical approach is already paying off. It looks like several key parts can be installed the wrong way, which is asking for trouble and no doubt contributes to these kits' reputation. They don't leave much margin for error! That steering servo is a beast, definitely makes a difference. Looking forward to seeing more.

I'm a big fan of the 234/1 personally, but that's probably because I think autocannons are cool.
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Re: 1/16 RC Sd.Kfz. 234/2 Puma armored car - lmcq11 build

Post by MichaelC »

lmcq11 wrote:Short video of the first field trial outside on uneven pool deck made of cement. Everything is looking good out of the box, no issues. The gears and drive shafts are still a bit stiff but getting better as they get some mileage. The 8x8 steering is surprisingly excellent. The wheels are turning perfectly on cement even when the vehicle is fully stopped. That 35kg servo is making a difference.

phpBB [video]


Regards, Louis
Louis looks great and runs perfect. I will have to take mine apart and follow your steps ! I had lots of difficulty with the steering specifically and have to change the servo that comes with the kit.
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