I'm simply using a Y-splitter cable with the steering servo and the DMD's Ch 1 (Rudder) yoked together and plugged into ch 1 on the receiver. It seems to be working just fine. As you apply more left/right on the stick, not only do the front wheels turn, but you can see gearbox apply more left/right track accordingly. You could probably use one of those V tail mixers in order to control how much, but I'm satisfied the way it works with just the Y-splitter cable. I'm guessing it would work fine with the WSN gearbox or any other really.

Hi Guys,
You have inspired me and I ordered a 251. It's the rocket launching that I'm not to keen on but it was on sale. I wish to RC it and have an old 1/18 PZIV as a donor for the trans. My first question is, are there other gear boxes out there ? If I use the original gearbox, should I also stick with the electronics from the PZ IV ( I believe it is an 21st Century tank ). Or, use an HL electronics ( $ matters ) I also ordered the 88MM anti tank/ aircraft gun. Could a 251 pull the 88 ( minus the rocket launchers )?
Just some thoughts as I get ready for the project.

As is always, your help will be greatly appreciated.


Jim

Dave, your idea of using a Y-harness cable is not only a good one; but it mimics reality, too. I've read that German halftracks used a steering system whereby when the front wheels turned more than fifteen degrees, the braking system would start to act on the track on the side of the turn. And, that this was the reason that German halftracks didn't need a powered front axle to help "pull" the vehicle through the turn - unlike an American halftrack, which did. Even the little Kettenkrad used this system, and there are photographs of it operating with the front wheel missing entirely, due to the steering system.

Great build! -Mike

CountChocula,
I have the 251 that I want to RC, If I were to get the Tamiya tracked vehicle chassis kit, would that transmission be better then the one in my 21st Century PZ IV? Fantastic builds by the way.

Jim

Hi 1sgt,

From what I understand, that Tamiya kit gearbox ( have one too... with those gold looking gears and gray casing?) is noisy and weak. I think Rex Ross mentioned that as well on the 1st page of this thread. I would definitely go with that 21st Century PzIV gearbox. That thing has been rock solid for me so far. I haven't driven mine too much, but so far, it's really strong and I don't notice any slipping of the gears. If you're building it to battle, go with the 21st gb. If you just drive it around here and there, the Tamiya one would probably be ok.

Dave

I think I once seen a site that sells VS tank ( or one of the new smaller R/C tanks) parts and they had a good looking gear box that would be a good size for a 251 ??
I will try and find it again.

I haven't had too much time to work on the HT as of late. last night and today, I was able to cover some ground. I'm going to use a HL/WSN turret traverse, but instead of using the ring gear, I simply modified a Bandai road wheel plug/cap, cut a hole in the traverse gear, then mounted the cap directly to the final gear shaft. I will mount the turrect directly on to this plug in the center. I went this route for obvious space reasons. One of the pics shows what it will look like once mounted in the compartment directly on top of the DMD.

I also have been working on the turret itself and have cut some templates out of construction type paper and hope to cut out styrene pieces using these as stencils. I made a guide using some wire and angled it to 60 degrees in order to ensure I cut the templates to the proper (or consistent) angle for each piece.

I also replaced the rear plate from the .060 thick styrene to 1.18 stock. This reduces rear flex and gives it a more solid feel/construction.

I'm obviously taking some "artistic license" here since the scale and dimensions aren't correct since this started out as a 251. But... I hope it looks close enough when I'm done with it.

Here are some pics.

Nothing like scratchbuilding to make you feel like a true modeler!

Well truth be told, I'd rather be building off a set of instructions! I can't believe how much thought/time/work/trial-and-error goes into each area. You take this all for granted when you read off of instructions and reach for parts bag C and glue part 1 onto part 2!

All this aside, It's been a fun project to work on and great learning experience. True modeler? Yeah right!

Using the paper templates, I traced then cut out the pieces using .060 styrene stock. I then CA's them to the turret base plate. It's a little rough at this point so filler will be needed along with some sanding etc. But it gives an idea of the overall size of the turret when setting on the body. Due to all the angles, I went with the 6 sided turret (which was more prevelant on the "neue' body anyhow since it was easier to manufacture) instead of the 8 or 10 sided version on eariler models.

I was able to spend some time on the HT over the last couple of days. I accomplished quite a few things with still more to do.

1. Realizing that I needed more room (especially for the turret traverse mechanism), I begrudgingly decided to raise the ceiling of the HT enough to house all the components I needed. I didn't want to do this since it changes the look completely, but it was needed to make this work. I thought about following the 60 degree angle of the side plating, but this meant I had less top surface area for the turret and would have caused a major turret overhang problem on the sides. So I chose to just go vertical and live with it. To accomplish the lift, I used some evergreen .125 stock and basically built a frame around the top.

2. I also cut out the MG slot and sighting scope slots on the turret. I then made my first pass at a 18th scale 20mm cannon. It's not perfect, but I think it will work for now. The plan is to mount the emitter either under the MG, or, possibly under the 20mm cannon if I can get elevation to work. I don't have much room but am considering some sort of server type of elevation.

Here are some pics.

Dave

That looks really good to me. I like it!
Rex

Thanks Rex. Coming from you, that means a lot. I've been admiring all of your scratch builds out here for a while now. You're the master at this scratch building stuff! I just took this on because I can't find a tank I really like! =)

I was able to make more progress this weekend. Two of the main areas of focus were a mounting for the TBU, and doing some modeling/detailing of the rear.

Fashioning a small brass strip and bending it into shape, I mounted it to the bottom of the TBU. Then, I notched a small portion of the upper right side rear of the top of the HT. The brass "clip" allows the TBU to simply hang off the rear of the HT. I went this route due to space limitations in the turret plus I can clip it on and off quite easily.

I considered just mounting a fake rear access door, but I thought it would be cool to have a real working rear door. So I measured and cut out a door. I then cut out the thicker rear styrene for the door to go over. Using some hinges and other odds and ends I scavenged off my Bandai PzIV, mounted the door, view port, and rain guard over the door. I plan on mounting a Jerry can to the right of the door later.

Anyhow, here are some pics. More to come!

Dave

I put a coat of primer on in order to help me see where filler/sanding/attention is needed. I was also able to fabricate a simple (if not clunky) elevation system using a sub micro server (Hitec HS55 Feather) and a potentiometer (pot). The pot is larger than I need but it works for now. I may replace this with something smaller in the future but for proof of concept, works really well. I'm able to slow down the elevation speed quite nicely this way. I can also elevate the gun to 80 degrees (which the 250/9 could do for AA purposes) although I'm not sure who I'd be shooting at, at that angle! Maybe Craig (Streetsquid) setting on the bridge but since he's German, so much for that. =)

Anyhow, here a a few progress pics.

Dave

Dave,

Nice job on the project. Looks very good.

FYI, I used a Camera Position Controller from Dionysis Design http://www.dionysusdesign.com/produc...roducts_id/190 instead of the variable potentiometer for all of my TD custom servo elevations. When used in conjunction with a servo, the camera controller gives a nice slow elevation and also keeps the servo (correspondingly, the cannon) stationary (and on target) when the tx stick is returned to center (versus normal operation of returning the servo position to neutral too).

I'm guessing you'll be battling this in 2 weeks?

Thanks Jeff,

And thanks for the info on Camera Position Controller. I'll have to see how that works in practice since I can't see how much it slows down the servo. Will you have any of your tanks using that system with you on the 23rd? I'd love to see it and how it all works. Since I'm not using a digital radio that could help, I'll have to come up with either some sort of slipper clutch or stops to keep the barrel from snapping off if it goes too far. I'd rather not use that pot if I don't have to even though it gives me the speed I'm looking for.

I appreciate all the help and advice as I'm just stumbling my way through this one piece at a time! =)

Dave

Dave,

I've got a loose one of these camera controllers that I'll bring and we can install and live test on your 250/9 at BD.   You can install it and see how it works compared to what you've got.  As to limiting travel on my previous servo elevation units, I customized the length of the pushrod to get proper travel versus programming the servo.  Kind of stupid, but it works.  

Hey thanks Jeff.

I'd love to see how that works for sure. I soldered the leads from the servo to the pot so I can de-solder them if need be to test this out. With my gun setup, I don't actually have any push rods as the barrel is directly mounted to the servo arm. This is how I can get such a great range of elevation like the real ones had. I just don't know how to stop it one way or the other at this point. I'm going to mount a fire button to my Skysport so I won't have to worry about elevating the gun by accident while trying to fire.

Yeah, I'm hoping to have it battle ready by the 23rd, but there still alot of things to do yet. I also want to have the wire mesh roof in place as well to hide some of these components as well. We'll see though. I'm still not sure my front end suspension will even hold at this point! =)

Thanks again for the info and bringing the controller out to the BD.

Dave

Getting closer!

Looking good! That'll be a tough opponent in the built up areas....but not to us uber allies.

Thanks Duane, it's been a lot of work especially as of late in order to have it ready to battle by the 23rd. It's pretty much done now with the exception of a few things such as the split screen roof (it's just setting on there for now) and getting the body to set/fit correctly in the rear as can be seen by some of these pics. By the way, does anyone know what to switch the SW1 and SW2 switches on the MFU to set it to light?

Dave

It looks great, good job!

For light both switches go toward your sound volume control (or away from the communications plug). See you tomorrow.

Well, after having battled the little 250, one thing became clear. The AAA battery solution wasn't going to work! At best, I could get in 2 or 3 battles before draining the batteries. At the last battleday we had here at DAK, Jeff Ousley once again encouraged me to try the LiPo route instead. I considered it in the past, but the batteries were still to large to fit inside the Half Track and that would mean getting a new charger, batteries, etc.

Jeff suggested putting them outside the HT which got me to thinking right away. So... here is what I came up with. It's a first pass and it's not finished yet as there is more painting, weathering, etc. to blend it in better still ahead. Basically, it involves covering the batteries in a canvas type of material, some small threaded string, and a plastic duffle bag off a New Toys Mellinium M113 APC that I cut and hinged to the side of the HT to hide the wires. The batteries are as big as I care to get given the small size of the HT but they're twice the capacity of the AAA solution I had.

Here are some pics.

Dave

Very unique solution, have you tried in a battle yet?

i just wonder if you go on a bit of a hill on the left side if it will tip over on its side looks like it would be too top heavy to the right side