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The start of an investigation: Seki 1:10 Tiger 1

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The start of an investigation: Seki 1:10 Tiger 1

Old 11-20-2014, 07:45 AM
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Gun Tech
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Default The start of an investigation: Seki 1:10 Tiger 1

Hi,
Yes it's me again, the FNG. Last night was the start of what should be an interesting endeavor. Being the type that goes overboard and always seeks out the lunatic fringe, I just received a Seki Tiger 1. First off, I wish to express my sincerest thanks to Tanque for his willingness to provide some detailed information to someone he doesn't know from Adam. He was able to provide some experience with the gas powered examples and acknowledged that he was aware that some electric models were produced. This is one of them:






To put size in perspective:


That is my Taigen T-34, it really feels inadequate!

I did apply power to see how it would work, since the electrics are really complex and I can't read Kanji, I just applied a full 7.4 to the motor, but it is made for 12V.



This thread will have to kick off with that for now, I have more photos and will try to keep a good record.

Mark
Old 11-20-2014, 07:51 AM
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Whoa... what a behemoth! And I thought my 1/6 M5's were large.


I don't have the room for a monster like this but it's neat to see there is interest in them still. I'd get a hernia transporting it around, let alone working on it. Nice score and you know we're all jealous!!





Jeff
Old 11-20-2014, 08:07 AM
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Jeff,
I promise my purpose is not to stir jealousy. Anyone that knows me, I have a nasty habit of going straight to the road less travelled and my mechanical background drives my interest in stuff like this. Luckily, even as uncommon as this is, I foresee that few will criticize if I bring the electrics around to a bit more modern technology, not that I am one to care, but I will preserve anything I remove for the "purists". As Tanque warned me the level of detail is very simplified and that should be interesting to learn from others here where I can make improvements. The first thing I see being upgraded is the speed control, it is a large assembly of 5 micro-switches to produce 3 forward speed and 2 reverse with a convoluted terminal board and a pair of "resistors" (bare wire coils acting as heat sinks). There are other bits that I am trying to play Sherlock Holmes and determine their purpose. I took it out last night for an uncontrolled run by manually connecting the battery and walking along with it, I made steering changes by reaching in and twisting the steering servo. Crude but fun!

Mark
Old 11-20-2014, 10:18 AM
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Tanque can confirm this, I think the Tiger I is more accurate in appearence then the Tiger II that Seki produced. A lot of the detail is simple, but way better than the Tiger II. Nice find and should be fun to modernize.
Old 11-20-2014, 10:26 AM
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Maus45,
I believe you are thinking of the Sankyo, that thing looks like a Tiger if you are 50ft away. As I said, the detail is simplified, but appears accurate for scale. The funny part is the turret, it has no underside and is rotated by what was once a rubber coated drive wheel (now rock hard and crumbling) contacting a wooden disc. The rest of it is sheet aluminum and castings for the body. The chassis is a proper torsion bar suspension and the drive mechanism is built like a brick outhouse.

Mark
Old 11-20-2014, 10:30 AM
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The key here is that I need to sort out what kind of power the stock motor produces, because if I could reduce its size with one of the modern crawler motors and/or a gear reduction, it would allow me to set up all of the electrics for 7.4V. As it stands 12V is too much for the ESC I have in my KT and I don't know enough about that part of this hobby yet to find a suitable unit if I keep the motor that is in it.

Mark
Old 11-20-2014, 10:45 AM
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Mark, you are correct, it is the Sankyo. Very crude scale look. You may want to look at this as a possible replacement ESC.

http://www.dimensionengineering.com/products/syren25
Old 11-20-2014, 11:06 AM
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MAUS45,
THANKS!!! Some of the description loses me, but several numbers jump out as working within my range. Most of the wiring in the tank is still pliable, but I see the need for replacement in the near future anyway, so if I start in on any changes I will be committed to a total overhaul. That being the case, I need to develop a system that will be all inclusive so I don't wind up with a wiring harness looking like it was patched together by Bubba's Ang-gin-nearing. I am not afraid to jury rig things for testing, but I cringe when patchwork butchery is an acceptable norm. As for the motor, I may see if I can borrow a manual tachometer to nail down what the output RPM is, as for torque, the gearing seems like it does a fair amount of the work and with the huge improvements in electric motors, that is why I am hoping I could reduce its size to a more common variant with a "normal" voltage. If I have to stick with 12V, so be it.

Mark
Old 11-20-2014, 11:35 AM
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You could use a Tamiya DMD for the ESC if it's dual motor. Used up to 14V on a tammy DMD before it gave out and reset, plus if you do blow it you can send it back for a replacement. (just may not want to tell them about the 12V though.) The only thing that may be an issue is the amp draw from those motors and the weight of the beast. Plenty of people have converted 1/6 Stuarts using the tammy electronics though.
Old 11-20-2014, 11:39 AM
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Benny,
This thing has a single 12V motor about 3" in diameter and 4" long as seen in the video. It uses 2 clutch systems for the directional drive/steering. Very different world from the Tamiya, but thanks for the input.

Mark
Old 11-20-2014, 01:07 PM
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Not too different than the first generation tammy's that ran on one motor and used 2 clutches, just bigger! One motor is the kicker though to use the DMD, it's been done, but hard to get the exact
resistance needed on the unused motor leads for the DMD to operate properly. Good luck on your adventure!
Old 11-20-2014, 08:50 PM
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Originally Posted by Gun Tech
Maus45,
I believe you are thinking of the Sankyo, that thing looks like a Tiger if you are 50ft away. As I said, the detail is simplified, but appears accurate for scale. The funny part is the turret, it has no underside and is rotated by what was once a rubber coated drive wheel (now rock hard and crumbling) contacting a wooden disc. The rest of it is sheet aluminum and castings for the body. The chassis is a proper torsion bar suspension and the drive mechanism is built like a brick outhouse.

Mark
The Sankyo was a 1/12 attempt at a King Tiger. While it was powered by the same excellent transmission that is /was used in their 1/10 type 74 and 1/8
scale type 61 the KT failed both as a model and an approximation of a KT. I had one, I know.

The Seiki Tigers were ( and are ) great models of their time. Excellently executed, strongly constructed and easy to maintain. Consider that most any example found today is easily 30 years old and if properly cared for I'm sure they'll last another 30. I hope more guys find these things and bring them back to life.
Sure they're dated by today's standards but as is said in Real Estate they have great bones. I stop myself at saying they have the unsurpassed benefit of being in the wonderful 1/10 scale, the most sensible of the large scales. Oh wait I meant to say they're all metal...

I have 3 Seiki Tigers all originally gas models; the third I converted back to gas. The only drawback in my mind is that the models aren't geared low enough
for my liking; at least the gas models. This in my opinion is the result of a decision to use a single compromise gear ratio that more or less works at the high and low ends of the throttle; If I had been the developer of their transmission I would have either used a much lower ratio or given the transmission 2 speeds.I prefer power over speed in my models; a lower speed model is much easier to drive well. I plan, someday, to explore options to lower the speed on my models as I purchased sets of Asiatam's 1/10 scale steel Tiger I tracks some while ago and they won't really work for effect in a racing Tiger.

I purchased my first Seiki Tiger used in 1979; it is an early gas job with conical brakes, the later versions had disk differential brakes for steering.

Somewhere I may still have a factory video from Seiki where they ran a 1/8 scale Sd Kfz 251 gas powered ( 4 cycle) using a smaller version of the gearbox used in their gas Tigers; I never saw their half track but in that video . Also they ran what I can only imagine was a prototype gas Tiger I powered by tandem Saito .30
4 cycle engines; again only seen in the video. Seiki as a company is sadly long gone, come to an unfortunate and inglorious end on all accounts.

So go out there and find those Seiki Tigers ( leave mine alone!) where ever they're hiding and get them going. If it needs to be said I'll offer any advice and help I'm able to any who want to travel that path....

Jerry

PS: Here is an image of the later style gas transmission I rebuilt several years ago. Centrifugal clutch on the left disk brakes on the right.
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Last edited by Tanque; 11-20-2014 at 09:03 PM.
Old 11-21-2014, 08:04 AM
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Jerry,
Again, I must say thank you for your input, you are an invaluable resource for this field here in the states.

As I spent another couple of hours noting the functions of the components and again looking at the layout of the gas powered transmissions, I now realize that there are no similarities to what has been used in this transmission. This system is essentially an overgrown clutch type steering unit that most likely paralleled or copied the Tamiya unit. There are a couple of very strange components and functions of this system that still puzzle me. First, the electric motor is not secured and is designed to rotate in its mount about 30 degrees. Second, there is a linkage that utilizes that rotation to engage one of two uni-directional bearing equipped gears against a "clutch bell"??? It is a puzzling feature and the best guesses are either a de-coupling unit if torque goes too high or some form of "hill holder" to prevent free wheeling while climbing or descending a grade. Here is a photo of these strange gears:



This is the "clutch bell" viewed from the top:



As Jerry stated, the "bones" are there, so I will get a speed controller on its way shortly and pick up another receiver, so that I can start upgrading the electrical to electronics and start opening up some real estate. I will also replace the rather crudely mounted servo for steering with something mounted in a bracket instead of held with a band clamp as seen at the far left of the second photo. While I am at it, I will try to replace all of the wiring with something a bit more pliable along with modern connectors. I did try running it with a full 12V, again, I just hot-wired it at a full 12V initially, but I did try running it through the speed control and it does work. There is no smooth increase, it goes from low, to medium, to high as each micro-switch is engaged by the cam. There are these two "resistors" that shunt power for the lower speeds and the little buggers get screaming hot!



I did take another extensive series of photos, but didn't have a chance to upload them yet, so please be patient. I can hardly wait to get this sucker underway as a true RC, because even running it manually it just grinds along and the tracks click and squeak just like its big brothers would.

Mark
Old 11-23-2014, 09:11 AM
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Okay, current findings. After further tinkering trying to discern what those strange one way gears are, they appear to be a means to prevent the tank from rolling in the opposite direction from the current direction of travel. In other words, if you are climbing a steep hill and stop, the tank will not roll backwards under its own weight. This however, will mean that if you are descending an equally steep grade, you would freewheel downhill unless you applied reverse to check the rotation of the bell-shaped housing. Thanks to the link from MAUS45, I have an ESC on order. Just for laughs, I pulled the motor out and swung by a couple of the LHS's and asked about a replacement, boy did that throw them for a loop! Needless to say, they all thought I was nuts, but admitted they never had anyone come in looking for parts for a 60lb tank. On a more serious note, I am going to see if one of my co-workers has a hand-held tachometer so that I can find out what the no-load RPM is on that motor (which is annoyingly unmarked), in case I ever should need or desire to replace the motor.

This is a video of the speed control at work, please excuse the crude camera work:



This is the motor at full tilt with 12V applied direct:



You can see the way the motor rocks in the housing and the linkage pops off because full power is applied so quickly.
Enjoy!

Mark
Old 11-23-2014, 09:38 AM
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As you probably surmised these models are not for those folks who don't like mechanical sounds, the sounds of gears meshing and doing their magic. You'll be better
situated to add sounds to this model than I am as the sound of the engine from mine makes the addition of special effects sounds impractical. I would however love to find a
unit with with I could just simulate the sound and flash of an MG 34 that I could use during the relative quiet at idle.

Is Vantec still in business? They used to make great higher capacity speed controls.


Jerry
Old 11-23-2014, 10:50 AM
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I just looked and Vantec is still in business, so they are still a source. I am already wondering about building something in the future to keep this Tiger company, but the lack of affordable (
Old 11-23-2014, 12:31 PM
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Out for a Sunday drive! (at 7.4V only)

Old 11-23-2014, 02:47 PM
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Originally Posted by Gun Tech
Out for a Sunday drive! (at 7.4V only)

LUV That Sound! Thanks for Sharing!
Old 11-29-2014, 10:54 AM
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Well, the postman brought me a present yesterday! I now have my ESC installed with a 2.4gHz RX.
I cleaned out a lot of gear! Now I have lots of room to work with.




I also had to swap out the servo for a conventional plug type as I had this odd-ball


For some reason, as yet unknown, using my DX4 and a 4ch RX, I tried to run the ESC from the elevator, but it wouldn't work, so I am going forward and reverse with aileron, the steering is via the rudder. A little odd to drive, but it works for the time being. Here is this mornings test run as an RC!



I came across one puzzling feature that has me curious. When I looked at the plugs for the batteries, they were wired in series (=24V). So it may be possible that this motor was later run as a 24V, because looking at the manual, it originally appears to have a total of four 6V batteries, with each set of two 6V in series for two 12V parallel inputs to the motor (12V total). I can see that the wiring is different at the plug junction from what was shown in the drawings. If anyone has ever heard of the actual operating voltage, please chime in. For now, I made a temporary harness with both 12V batteries in parallel, since I would rather run it at the lower power until I can be sure.

I also noticed a quirk about that odd anti-reversing gear, if you are going in one direction and slowly back off to a stop and then apply power gradually in the other direction, the motor doesn't torque enough to engage either gear and it will free-wheel. That meant I had to blip the throttle to make sure I was engaged. It drives very smoothly, but I don't know how much power it has for climbing just yet, I didn't want to tear up the wife's landscaping.

I need to get an auxiliary BEC for the servos, since the manufacturer, states that the built in BEC may not be adequate once you start loading the circuit down (turret rotation and elevation), for now it was up to the task for the steering servo. That's all for now.

Mark
Old 12-01-2014, 06:21 AM
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here is a site you might already know about, perhaps he still makes the parts?

http://www.sdkfz-modellbau.de/modelle.htm

Guntech you really sound very savvy at deciphering how things work just from experience and eye-ballin'! I too took up the hobby mainly for the mechanical challenges, of constantly re-engineering and improving our hobby grade tanks- but this would blow me mind!
Looking forward to seeing you perfect this rare Tiger 1, I can tell by your determination and effort nothing less is likely to stop you from finishing. And amazing model it will be someday soon too.

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Old 12-01-2014, 07:28 AM
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I believe Thomas Wittgrebe, a friend of mine and the owner of that website told me some years ago that he has stopped production of his models.
He may offer parts on a limited basis but I believe his regular production has stopped for some time.

Jerry
Old 12-01-2014, 07:57 AM
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Since I was successful with my changes, I gutted the tank down to a bare hull and removed all of the coagulated grease. I also stripped the gearbox of all of the old lube and gave it a fresh dose of synthetic lube. I have lots of pictures, but I will need to upload them later today and I will add them to the post. It took about 8 hours to take it down to parade rest, clean, lube and reassemble.

Mark
Old 12-01-2014, 11:18 AM
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Marc780,
Thanks for the compliment, after almost three decades of gunsmithing and my current job, working on cannons for the Navy, I have to figure out what makes things tick when there is no reference material to use. I love the challenge of getting stuff working and when I can fabricate improvements, it makes it even more fun. Yesterdays disassembly binge comes from a latent OCD streak that manifests itself through stripping things down beyond the "normal" level and making things squeaky clean. That way if a problem develops down the road, I know it is not from pre-existing neglect. Hopefully the future upgrades that involve electronics won't leave me gibbering in the corner (I hate electrons, even though I was an ET in the Navy). By the way, I forgot to mention that I did discover one damaged part. One of the suspension arms had two cracks on the flange for the wheel pin, it was probably from a drop or side impact and it doesn't look like it will impair operation or get worse unless it gets hit with a hammer. I will keep an eye on it and if necessary, I already thought out a way to machine it and reinforce it with a band of steel if it gets on my nerves.

Mark
Old 12-02-2014, 07:39 PM
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Things just got weird. I just secured a deal on another Seiki, so this one will have company. Unlike this one, the one I just got started life as another electric model, but was converted to gas. I won't see it for a couple of weeks, so the questions will gather in my mind until it shows up. I will likely try to paint this new one up as a companion from the Tunisia campaign if it cleans up well enough.

Mark
Old 12-06-2014, 10:29 AM
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Went on a binge and made a new wiring harness and tidied everything up. I also got all of the pictures from the teardown and cleaning loaded and I will play catch up. Enjoy!

































The battery tray looks like crap. I will see if I can machine one today.

Mark

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