Weight Distribution and
 

Hey peoples I'm new, not just to the forum but to rc tanks! But not to RCs. but man the closest thing I've ever seen to my tank (Henglong M41) is maybe the "BLizzard" snow cat looking RC that my friend has. I understand the basics of what controlling two motors at once is all about but have no experience with those specialty escs or any kind of mixing with traditional escs, and on top of that the tank has a board which is alittle different and has a lot more pins and wires than I'm used to.


So on the Henglong I've driven it around and I really.. well I was really disappointed it the performance, I'm into scale crawling and my tank does the opposite of what I'd like it to do.
On flat smooth ground trying to start up slowly the motors are already stalled out lol. If I slowly move the stick forward it will eventually lurch forward and then its mostly fine. The controller wins worst quality of any of my RCs.

It does have metal tracks and wheels so maybe that's why the small stock motors are having trouble. they are not too tight.

Ive ordered a V2 taigen gearbox which will come with 390 size motors but beyond that, is there anything else than can help make it move more realisticly? The shorter gear ratio and stronger motors will help but I was just wondering how big is the next step to a better controller and throttle resolution?

Oh and the tank is very rear weight biased.. Do any of you add weight to the front to make it drive better?

First, the stock taigen V3 control unit will give you much better control than the Heng long unit and it's a cheap option. However, your best bet is to go with a hobby grade board like a Clark or an IBU. The difference in control is just amazing. The Walker Bulldog is, in my opinion, a really nice little tank that gets overlooked by quite a few. When I get home from work I'll post a couple videos of mine because I've done something unique with it. My m41 has two different Hull tops. One is stock and has a regular tank turret, and the other is one that I converted over to a quad 50 anti-aircraft tank. The tank runs with TG ball bearing gearboxes, 380 Motors, with metal tracks and sprockets and with the Clark tk20 it really, really runs great. If you want to maintain accuracy, you don't want to change your tracks. I know the other tracks can grip better but they are historically inaccurate and that's why I stuck with the stock m41 tracks in metal.

Ok cool. So I didn't expect to be able to use a higher voltage battery, that should totally help. Add some weight to balance it out.. that will be (hopefully) an easy task.

I'd love to get my M41 to the point that I can make an Tank vs. Rock crawler video.. of course at the end the tank shoots the truck and blows it up haha.

I wish you said the stock tracks work better because I paid the extra money for metal tracks and then painted them and everything, but I probably need the driving experience first anyway before I can take advantage of a grippy abrams track.

I'll check out your build thread for sure.

Thanks for the info. on the other control units/boards! I didn't realize the Taigen's had a unique control unit compared to the Heng Longs. After I get some experience with the stock controls and upgraded gearbox/motors I'm sure I will start looking towards this.

When I was looking at tanks for some reason I gravitated towards the M41! It just seemed so random amongst the many WWII tanks and I'm always a fan of the underdog :)

I understand completely, and I'm a big fan of the Bulldog myself. One of these days I'll get around to building one of the Bulldogs from the movie Apocalypse Now. One thing you should keep in mind is that the HL Bulldog is not true 1/16 scale. It's actually closer to 1/14 scale so to make it completely accurate you would have to narrow the tracks and lower the hull and a whole bunch of work that I just don't think is worth it. It's a sweet-looking and sweet running tank just the way it is and it's always good to see another Bulldog fan show up on the Forum.

Ok so I'm too new to post URLs or pictures of my tank I guess .. but I can tell you that if you search " M 41 English" on youtube you will find this old VHS copy of some upfitting program video from the era, and it starts off slow with just some guy talking but then it has the most awesome footage of M41s driving I've seen yet.

So here's my M41 with a Clark TK22 and the stock hull top.


And here with the AA top.

It does seem like a good combination with the Tk22! The AA version is really trick, the smoker unit works really well.
Did you actually time it with the engine start or does the TK22 bind it together? And your headlights work remotely too wow.

Ok so I've opened up the M41 for the first time and started making some changes.

First I removed the non-functioning heng long smoker unit. I just never got it to work, although it was moving air no smoke.

I want to move the speaker to in between the new taigen gearboxes, but they are still in the mail so I can't tell if it will fit. But it does appear to fit with the stock gearbox. Also now the wires are too short to reach from the speaker in the rear back to the board.

The layout and compact size of the RX18 is pretty sweet, and the wire management was surprisingly adequate (although I'm not a fan of twisted wires) I even saw a few mini cable ties in there. The overall build quality and connector fitment etc.on the board is really bad. Mine was not even closed all the way and I just barely got the plastic to snap together. It's a few steps back from the waterproof, and sealed escs that are available in other RCs.

So the reason why I want to move the speaker between the gearbox is to add some weight to the front, which I did in the source of a large square aluminum block I was using as a paper weight. I think its just the right weight, if it was steel it would probably be too heavy! After checking to make sure the upper hull would still fit and snapping off some plastic bits on the bottom to make it fit better I used gorilla glue to secure it. I didn't want to use double sided tape because it would have made it taller and possible interfere with fitment.

The motors are really small, if they didn't have that gear reduction they would be toast!

I took a picture but I don't think I can post them cause I have like 4 posts lol

If you run with the speaker between the GBs you won't be able to use a smoker, and I believe you liked the effect on mine so do you really want to give that up? I just use a stock Taigen smoker from Imex in Florida and they're only ten bucks a pop. For a long time I would automatically have Erik add two smoke units and two airsoft units (also ten bucks) to every order I placed. I found out early that smokers and airsoft units are prone to failure (even though they've gotten more dependable as time goes by) but they're cheap and easy to swap out so I guess I've just gotten used to it.

I understand about the weight in the front but I don't think aluminum is the best material for that, being light weight to start with. I just use simple lead sinkers from the fishing tackle box. I hold them in with Zap Goo and they come in all different shapes and sizes. Usually the split shot, about a quarter inch in diameter, work very well. You can tuck them into nooks and crannies so you don't waste space, and I just weigh out a handful on my postal scale to get a starting point.

You might want to look into a better control system. The hobby grade boards, like the IBU and the TK22 like the one in mine are a popular choice, and there's also the Asp and the Elmod. The TK22 is by far the most economical at about $100 including shipping from RC Tanks of OKC. That's Nathan's outfit and he's a good guy and an avid RC tanker himself. It does have it's drawbacks, though, as you need a special TV remote and an IR programming device to set it up, but once you have those things they work for any subsequent Clark products you buy. When I first started out I was buying HL tanks with the old 27 MHz set-ups and the control was horrible, so I found a cheap way to get better control was to install a Taigen MFU. Now they're up to the V3 control board (also called an MFU, for Multi-Function Unit) and I think it's a very good, low cost option for airsoft tanks. It's around $60 and works with any hobby grade transmitter, like my favorite tank TX, the FlySky i6. I have some videos of this set-up if you'd like to see them. The new V3 MFUs have proportional turret rotation speeds, very good sounds (although they haven't come out with a Bulldog sound module yet) and a feature to disable that horribly fake track recoil when you fire the main gun.

Where are you located? I think it's great to see guys from other areas of RC coming over to tanks so I try to do whatever I can to help them out. If you need parts you're welcome to raid my spares box for whatever I can provide, and I'll try to help out with whatever else you need. That don't mean we'll be takin' warm showers together or anything like that, but I do try to be as accommodating as possible with guys like you, just to make sure your experience is a good one and you stay in the hobby. The more you spend, the better chance they'll finally come out with my favorite TD, the Hellcat! So it's not like I don't have ulterior motives, but in this case they're to the benefit of new RC Tankers. So just shout if you need anything, and I'm looking forward to photos once you have enough posts (I always thought that was a dumb rule, but I don't run things around here. In fact, the only thing I run around here is my mouth. ;) ).

You might also want to take a look at this thread.

https://www.rctankwarfare.co.uk/foru...p?f=22&t=26093

Louis has just gone whole hog on this puppy and he's replaced the too wide stock tracks with a pair of the proper width, narrowed the sprockets and idlers, corrected all the errors in the tank that HL let slide, and really gone crazy with detail. This is one of the finest Bulldogs I've ever seen, and Louis never ceases to amaze me with his skill and attention to detail.

Yes the speaker will fit just fine between the gearboxes even with the 390 motors. I put all mine between the boxes. No need for the "unrealistic" and "toy like" smoke units, but then thats just my opinion. I have seen some excellent realistic looking builds ruined by the look of white smoke puffs as exhaust.

Consider also removing (cutting out) the battery box. This adds a lot of space for larger batteries, adding weight and moving around/changing electronics as your build evolves. The M41 is a short tank and even with the battery box removed it is still quite structurally sturdy.

I wondered about the correct amount of smoke, but if you look at the YouTube videos of restored tanks running around you can see that some do indeed produce a lot of smoke! Maybe they are just bad restorations and the engine needs work. :) The Tiger 131 doesn't seem to smoke much.

Steve

I have not tested this, but the parameter inertiainit can be set = 0 to turn it off on startup. Also, it can be turned on and off with the transmitter:

The inertia (momentum) can be enabled automatically at startup by setting the appropriate value,
also it can be turned on or off by transmitter.
For Base version only one curve is available
For Full Option version there’s up to 6 different pre-loaded curves, you can set the desired one by
setting the related value
InertiaInit=0
Set inertia status at tank power on 0=Inertia OFF, 1=Inertia ON (at start up)
InertiaType=1
Set the desired inertia curve

I like the inertia. When you just let off the throttle, the tank slowly comes to a stop. If you want an abrupt stop, reverse stick. This engages the "brakes" and the tank stops immediately and the brake lights come on.

Steve

Smoke is pretty much a matter of personal preference. Some guys like it and some guys don't. Personally, I like a small amount of smoke just because I think it's a good effect but there are quite a few tanks that don't really produce any smoke at all. Like I said, it all depends on what you like. If you like the smoker, use it, if you don't like it, don't.

I'm with ya, Rich, I can't stand the inertia feature either, and I have no idea where they got the part about most people wanting it. Almost all of the guys that I know and have talked to have said they don't want inertia and even if they do want it they definitely want the option of turning it off. For close-quarters driving like you find in an IR battle an inertia feature is a definite drawback.

It might be because most of my gear boxes are older, but I've never had any trouble with the diameter of the TG shafts and the HL sprockets, it's the flat. I just take a diamond file and file down the flat a little bit and then the sprocket fits right on. That may have changed since the last time I did it.

Thanks a lot I really appreciate the heads up. I finally have time today to work all this out. Super impressed with the taigengearbox, and it came in a really nice box. I guess I ordered it with both the smaller motors installed and then the 390s in a separate bag.

I almost got depressed when I saw the position of the lower motor screws but they did leave some access holes on the opposite side of the gearbox.

I'll try and install it first and when I run into the problem you mentioned I'll see if I understand what you meant loll

Ok I see the problem, I need to make the sprocket side a bit bigger without messing up the shape of the key hole.

Also as luck would have it the leads on the larger motors are too short.. But the leads on the smaller motors ARE long enough. So, I bet if I just tap it with a soldering iron it will come off and I can switch them. The larger motors have what I think are little resistors that combine the +/- in series with the can itself. or maybe its some other way i'm pretty tired atm. they say 104, 10.4kohm? i'm studying this stuff for work/school so I only just know what I'm looking at but not much experience :p

One of the things I dislike about the IBU2 is it seems like you have to wait a couple of seconds before each "command". So if you try to fire the gun twice rapidly, for example, the second time nothing happens. You have to wait a bit and then fire the gun. I find other motions have the same "lag", too. Maybe that is what you are talking about with the backup.

I love the inertia. I like how the tank slowly comes to a stop when you take your foot off the gas but don't press the brakes.

Steve

Those are capacitors, and they're on there to prevent electromagnetic interference with the receiver. The 104 means 104 microfarads.

ah cool. thanks

Perfect timing, I guess I was hesitant to mess with the driveshaft since the gearbox is a lot more expensive than the sprocket but that does sound pretty easy.

I did one side already, then I have to reassemble the sprockets and tracks, plug everything and check before I put it all back together.

All back together, mostly. Plugged everything in and it works. Had to put longer wires on the motors and speaker.

at first it looked like the larger motors used the same gauge wire, whatever that is 20-22. but when I went to solder on the motor and actually look the longer wires were aluminum looking not copper. While the shorter wires that came on larger motors were copper.

So .. I just.. pretend I didn't see that and keep going. the wire nut is for one of the speaker wires. don't @me. Also this was during testing and I put some cable tie and tuck wires in along right side hull now so it won't interfere with turret or fitment.

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Surprise the larger output from the taigen gearbox has a larger bolt which doesn't fit through the metal HL sprocket. Where's my drill?.

Looks like you did a fine job. You'll find yourself acquiring stuff as you go, and one good thing to have is a jst kit (the white pugs that are everywhere in one of these puppies) and a decent crimping tool. An assortment of shrink tube never hurts, either. If you have a decent electronics shop nearby you're in luck. Ever since Radio Shack went belly up I have to order most stuff online. It can be really handy having a place close by for the basics, like wire and resistors and LEDs and what-not. You'll hear a lot of opinions on holding stuff down and a lot of guys like a hot glue gun but I prefer this stuff called Zap Goo. A simple Google search will find it, and I think it's great stuff for everything from holding wiring in place to securing stowage. It sticks like crazy, until you want it to stop sticking and then it comes apart fairly easily. But if you know something better I'm always up for new ideas. ;)

Looking forward to more on this tank, and can't wait to see video! :)

Thanks for your help. It's all back together now and even on the HL 1800mah battery its fast. definitely scale speed and enough that the tank rolls to a stop now which is cool. It is more controllable with the torque of the motors but it feels like the controller and rx18 are holding it back. Sounds a lot different now too with those makes a cool in sync whine sound when it starts

Here is a running video, I know its lame in my living room but its cold and wet outside heh.

I can't seem to get embedding to work. but hopefully it will be a link

Might want to consider taking out one link of track which will increase track tension. Yours are very loose and once you start running the tank in rough off camber terrain, rock crawling, soft dirt/mud you are going to "de-track" fairly easily. The photos below show one of my M41s with stock metal tracks properly tensioned for hard off road use. https://cimg7.ibsrv.net/gimg/www.rcu...cc0e57be41.jpg
https://cimg1.ibsrv.net/gimg/www.rcu...e995fbb032.jpg
https://cimg2.ibsrv.net/gimg/www.rcu...889f386c9c.jpg
https://cimg1.ibsrv.net/gimg/www.rcu...da3ce4dc90.jpg
https://cimg8.ibsrv.net/gimg/www.rcu...6afe837363.jpg

[QUOTE[color=#333333]=Fsttanks;12475273]Might want to consider taking out one link of track which will increase track tension. Yours are very loose and once you start running the tank in rough off camber terrain, rock crawling, soft dirt/mud you are going to "de-track" fairly easily. The photos below show one of my M41s with stock metal tracks properly tensioned for hard off road use. [/QUOTE]

Although I havn't had any real issue yet, I agree they seem on the looser side.

I have hard time using that Heng Long controller but I can't upgrade everything all at once.. I am pretty excited now though the tank performs well I think its going to be great to try outside for the first time. I worry about those stubby little road wheel axles and the little idler guys have been reinstalled a few times already heh. I know whats not going to break though.. that taigen axle.

Btw, your tanks looks awesome those later variant m41s are interesting some had 90mm cannon?

The majority of the issues with control while using the HL electronics come from the poor track to ground "grip" provided by the stock M41 tracks. Even with the slightest addition of power they break traction easily and this causes the track to spin faster than desired. Since tanks roll on their tracks this makes for handling difficulty. Adding weight to the tank will help to some degree, but it will still be touchy unless you swap over to "rubber padded" tracks with FAR FAR greater grip or replace the electronics at some point.

The metal control/axle arms for the road wheels are pretty strong and you will have to really work at breaking them. To date I have not broken a metal one and I drive my tanks harder and faster then most. I do not know what you mean by "little idler guys" are you referring to the three upper track return rollers on each side of the tank or the front hull mounted wheels (idlers). Either way there are easy ways to ensure the stay secure.

The M41 pictured in my last post has a modified turret to give it a slightly modernized look. The main gun has also been changed to represent a modern 90mm cannon.

OK so I took one link out of both tracks, I lost some downward suspension travel on the far ends but without a tensioner and the tracks being so loose before I still think better this way for outdoor use like you said.
Plus now I have two more extra links and pins! Sorry about my bad terminology I was referring to the smaller wheels on top.

I lubed them up alittle bit and they will probably stretch after I run it a few times and be just right. Hopefully the extra load on the drivetrain doesn't get things too hot but it will probably be fine. plus if anything breaks its good excuse to upgrade lol

The tracks will "wear in" as you run them outdoors and loosen up a fair amount. Your return rollers should now * "stay together" much better as they will not have the tracks "slapping" against them like before.

Unless you are running higher than 8.4 volts, heat will not be an issue. I run 9.6 volts in all my tanks and things can get hot, but this is easily managed with the addition of small ** "cooling fans" inside the tanks. The 390 motors can handle a lot of heat (mine have hit as high as 200 deg), it is the MFU (receiver) and power switch that have issues and need cooling assistance at higher volts or amp draws.

* If the return rollers wheels separate again simply add a "small" amount of automotive silicon ( I prefer black) to to the "male" half and press them pack together and let dry overnight. You can also use CA or epoxy but the use on wheels tends to fail sooner as they do not hold up well under hard use and the vibrations caused by it. Silicon tends to handle the vibration of hard use better. I am sure others have their technics as well.

** Small cooling fan can be added by simply using the "smoke" power slot on your MFU (since you have removed the smoke unit). You may have to splice the adaptor plug for the MFU onto the fan wires, this is super easy anyone into RC hobbies can do it (some fans come with the correct plugs and splicing will not be needed). The cooling fan can then be controlled on/off with the "smoke button" on the transmitter as desired. Another option is to use the IR port on your MFU to power a fan. There are a few "ready made" MFU covers that can be found on eBay with built in fans relatively cheap, around $20. These work well if you have limited space.

I ran a full battery through and made a small hill to crawl on, along with the tensioned tracks, and the results were the high side of OK @ 160F on the motors and 135F on the RX18.
there is really no where for the air to go in there. but a fan might help yea I'll have to try it. Interestingly the tank became a lot more controllable at the end of the battery life or maybe I'm just getting used to it.
I started at 8.4 and ended at 7.3 the tank still wanted to run though, and still had a lot of speed.

Unfortunatly the airsoft fun doesn't fire anymore, no sound or recoil from it. I doubt its the board since it shows no signs of trouble. but maybe I pulled wires loose from turret side.. I don't really NEED it to shoot but something to fix. it still traverses fine.

Those are relatively normal temps while running 8.4 volts. The fans tend to drop temps by roughly 10% in my testing.

The 390 motors coupled to the Taigen 3:1 gearbox on a light tank such as your M41 do handle well and smooth out when the volts are around 7.6 to 7.9 volts. As you increase the tanks weight this smoother handling comes in earlier in the battery charge/volt output. It is almost immediate if you swap to rubber padded tracks on a weight balanced tank, at which point you will be happy you have the extra volt(s) available.

Couldn't tell you what is wrong with the airsoft unit. I think I have one that is still installed and functioning. I "remove" them from my tanks for various reasons. But it is not surprising that yours is not working, they tend to have short lived lives.

Everything is a balancing act, electronics + battery + motors + gearing + weight + traction = handling desire for a given terrain or driving style. Finding yours can be simple or as complex as you want to make it. I have done simple and complex and have enjoyed experimenting with both.

I had a 2s lipo with a deans plug on it. my other batteries are 3s with traxxas, and I just use a traxxas to deans adaptor when I charge them using a traxxas charger. I ended up using the deans end off one of my adaptors and splicing and soldering it onto what used to be the Tamiya plug on the tank. So now I have over twice the running time and quicker charging. I ran it for 30minutes starting at 8.4 volts and it only dropped to 8.2v. That means even though I don't have a low voltage alarm at the moment, i'll have plenty of time to check it using my meter and it won't be so easy to run into low voltage because I estimate it will be over an hour!. Yes its a tight fit but there it is.
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