RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

inger
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by inger »

Another fabulous build Louis!

I know I am few posts behind here but I just wanted mention my positive experience with 3D printed parts. I am currently using parts printed for my project in two different materials using two type of printing system.

For really big parts such as bar armour, I am using PLA+. This is a thermoplastic made from plant starch such as corn. This material is really tough and when printed with a 0.01mm nozzle is able to reproduce small details to a sufficiently accurate standard. There is also minimal layering. For 1/16 roadwheels, this would be a a good material because of its toughness and ability reproduce details such as bolt heads.

For small high detail parts, I am using a resin called Samos 128 and SLA printing. This material is really tough but has the added benefit of being able to be printed with 0.05 nozzle which delivers a highly detailed super smooth finish. This would be a good material to use for making masters for molds and resin casting.

My two cents.

And BTW your drive solution is really clever - very impressive!

Looking forward to following this build.
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Herr Dr. Professor
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by Herr Dr. Professor »

How interesting! I have never seen--much less thought up--a cross driveshaft drive. You have explained the challenge of getting the angles right, and you indicate good speed control. Apparently 250 RPM is slow enough. That sets me to thinking about the mathematical relationship between drive sprocket RPM and track speed.
250 X some variable % of the circumference of the bottom of the drive cog = track speed = ground speed.
You can tell that I was no mathematics prof. :wtf:
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lmcq11
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by lmcq11 »

inger wrote:I know I am few posts behind here but I just wanted mention my positive experience with 3D printed parts. I am currently using parts printed for my project in two different materials using two type of printing system.
Thank you ! my personal expectations from vendors selling high cost 3D parts are high. I had a string of disappointments lately. I actually can't remember saying "wow" on any purchase of 3d parts. Vendor print standards and customer expectations are very wide it seems. I agree with the fact that I will need to design and print my own parts at one point.
Herr Dr. Professor wrote:How interesting! I have never seen--much less thought up--a cross driveshaft drive. You have explained the challenge of getting the angles right, and you indicate good speed control. Apparently 250 RPM is slow enough. That sets me to thinking about the mathematical relationship between drive sprocket RPM and track speed.
250 X some variable % of the circumference of the bottom of the drive cog = track speed = ground speed.
You can tell that I was no mathematics prof

The control board and sprocket size are also a factor. Not sure how the encoder at the back of the motor impacts performance. There are so many variations of those motors in 6 and 12 volts DC, different RPM gearbox from 10 to 1000+ and different quality. I used 160 RPM on the M113A2 build two years ago and found it to be too slow. Going up to 250RPM this time is a trial. I assume higher RPM means less torque, not sure. I picked good quality ones. I'll see what it gives for real only once the tracks are built and can do some tests. So far, it looks promising.
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HERMAN BIX
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by HERMAN BIX »

That drive shaft solution is a stroke of pure genius Mr Mcq11
I get that the notchy operation manifesting itself depending on angle is why CV joints are used in cars.
The velocity of the outside of the rotating joint V's the velocity of the inside of the joint effectively means there is a speed up/slow down each revolution of the shaft as a result of the angle if not addressed.
Out of all your cunning ways out of a sticky modelling situation, that drive system is an award winner :clap: :clap:

Its almost like the Canadians got their "Pimp My Ride" on with the 113 & made it something special :haha:
HL JAGDPANTHER,HL TIGER 1,HL PzIII MUNITIONSCHLEPPER, HL KT OCTOPUS,HL PANTHER ZU-FUSS,HL STuG III,HL T34/85 BEDSPRING,
HL PZIV MALTA,MATORRO JAGDTIGER,HL F05 TIGER,TAMIYA KT,HL PANTHERDOZER,HL EARLY PANTHER G,TAIGEN/RAMINATOR T34/76,
HL AN-BRI-RAM SU-85
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lmcq11
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by lmcq11 »

Thanks Herman, The M113 Lynx is a cool Recce vehicle, with retro features of the 1960s. The American selected the M114 instead and it was a major failure. Let's see how the motorization works with the tracks on. I am currently building them, should be done in a couple of days and will provide video.

First, i need to complete the exterior armor in order to prevent residue from the construction and dust from sanding from getting inside the chassis, drive shafts, etc. The rear panel is put on, with the overlay for the static hatch. The round corners of the hatch are done with the roundel tool.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
As shown in reference and contrary to the 1/35 kit, the armored roof is not flush with the side armor plates, it has a partial overlay to reproduce.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
Capture3a.JPG (82.99 KiB) Viewed 2064 times
The overlay layer is added to the model roof, the top being removable, it also hide the top joints for a nice finish. Nice smooth base to build on the details.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
Capture4.JPG (50.02 KiB) Viewed 2064 times
Side view of the frontal hatch with the water gutter around it and the large hinges typical of the M113.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
Capture4b.JPG (70.53 KiB) Viewed 2064 times
The large frontal hatch is installed with working hinge to access the motors and drive shafts inside the hull.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
The model as it stands tonight.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
The rear armor has the same overlay.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
Capture8b.JPG (68.24 KiB) Viewed 2064 times
Now i have a sealed hull. Other than building the tracks and test the integrations, the model needs a lot of details that will take time to build one after another, but it is mostly cosmetics, no more major technical design challenges.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
continuing on following post
Last edited by lmcq11 on Sun Oct 17, 2021 12:34 am, edited 3 times in total.
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lmcq11
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by lmcq11 »

Starting to build the tracks.

First the pins need to be prepared by removing one of the end point. Looks like the end points were molded on the pins. It takes pliers in 2 steps to remove them.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
Every links and pin attachment points need to be sanded and polished for a smooth operation. You can see the bleeding on the mouldings below. This is pretty hard metal to work with. It just takes time.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
Then assembled but without the rubber pads at this time. The tracks need to be built very tight, the end point is hammered on the pins but use of many pliers is required, sometimes i need to go back and reapply pressure to squeeze each connector, then file again. If the track pins are too loose on the links, the tracks will work badly. Some few links are also smaller than others by 0.5mm for some mysterious reasons. Because i think i will have many extras, the short ones are discarded.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
It also takes time to cut the extra length of each pins, and then file the tip. These metal pins are hard as nails and need large cutter and muscle to cut. Its not the first time i build these.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
I figure it will take a day or two.

Regards, Louis
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Raminator
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by Raminator »

Coming together with your trademark speed and skill, Louis. I'm looking forward to seeing how those tracks go with the driveshafts. I have faith in your engineering ingenuity!
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lmcq11
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by lmcq11 »

Thank you Raminator and everyone watching for your encouragements.

The new Tank Modellbau metal tracks are finally assembled, taking about 6 hours in total. I used a Dremel cutting disk to cut the extra length of the pins. They are without their rubber pads that will be installed only after painting. One pin has not been finalized for easy removal of the tracks. Being new and hand built, the tracks are still a bit stiff, showing it more at low speeds but they have much improving after a break in period of 30 minutes on the bench running at full speed. There is always a couple of links or sprocket teeth that cause more friction than others and need more filing. Keep in mind the tracks represents the NATO German made M-113 variant used later by Canada and other countries, not the American T130E1 tracks.

Here is a video of the motorization testing at various speeds. Its running pretty smooth for such a scratch built setup.

phpBB [video]


Regards, Louis
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Herr Dr. Professor
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by Herr Dr. Professor »

It is impressive to see the tracks and that cross-shaft arrangement running so smoooothly! Congratulations on an engineering feat supreme!
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lmcq11
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Re: RC 1/16 M113 Lynx C & R - Canadian army 1970s UN mission

Post by lmcq11 »

Herr Dr. Professor wrote:It is impressive to see the tracks and that cross-shaft arrangement running so smoooothly! Congratulations on an engineering feat supreme!
Thank you Herr Dr. Actually, the biggest challenge is to make the Tank Modellbau metal tracks and sprocket to run correctly. Whoever has assembled one of those tracks will understand. They still run with some unwanted tension on a few track links but it is really getting better compared to when i run them the first time. They need a lot of fine tuning, grinding the metal here and there, replacing a link here and there. Its like teaching a kid how to walk.

Continuing with the build, the following set of posts are for the commander's cupola and the other hatches.

On the Canadian M113 Lynx as shown on the 1/35 kit below, the commander's has an M26 cupola, manually traversed and armed with a M2 Browning heavy machine gun installed on a flat platform in front of it, and fired from inside the vehicle. To reload, the commander has to open the hatch. The observer has a regular M113 commander's hatch and fires a rear facing pintle-mounted Browning 7.62mm machine gun. The driver has a regular M113 driver's hatch.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
The M26 cupola offers good vision with all around periscopes. Notice the turret axle of rotation in comparison to its base. I have not seen this before.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
To complement the 1/35 kit that i found has some simplifications and mistakes, the web has excellent Lynx walk arounds with tons of pictures, i specially like the one on Net-Maquette.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
First task was to create the rings and hatch material for the 3 hatches, done with a roundel making tool with plasticard of various thickness.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
Rings for the commander's cupola and hatches are installed. Notice the two level deck.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
Basic shape for the M26 cupola is drawn.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
The creation and assembly is done in steps.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
The cupola was not given an interior due to lack of available reference.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
The interior will be painted black and will have a commander's figure.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
At this point, the frontal platform for the Browning stand is left larger than it should until i have investigated the situation further. I see a lot of differences between the 1/35 kit and some pictures on the web on the size of this platform.
RC 1/16 M113 Lynx Command and Recon tank - build
RC 1/16 M113 Lynx Command and Recon tank - build
continuing on following post
Last edited by lmcq11 on Tue Oct 26, 2021 9:12 pm, edited 4 times in total.
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