yoshigt2

I'm wondering about the durability of the Tamiya gearboxes. I love my Tiger I, decided to add some more to it. Picked up an ammo crate, bucket, metal crank handle, and metal tracks for it from Tankzone.com.

I know the tracks will be added stress for the motors, but how does anyone think the gearboxes will hold up?

Tanker 10

I think the gear boxes will be fine. You might want to consider a gear box brace and a better idler system that also will aid in the stiffening of the hull. I had a hull bending problem with my JS-2 until I bought the Henn Tec idler system for it. Now I can run the metal tracks without a problem.

yoshigt2

Thanks for the quick reply Tanker.

Gear box brace? Haven't seen anything about that in my searches. Must have missed it. I'll look into a better idler system for it. Is the Tamiya idler set just not strong enough?.

Panther F

Well, a lot of variables come into play here. Time used, conditions you drive in, YOUR driving and the weight. Usually the first that will fail are the cheap chrome slip-on gears... the final drive gear on the axles. IF you can get a set of IMPACT axles (they have a steel gear welded on the axle) using those will make it a bit more robust.

Keeping them clean of debris, oiled and a good tensioner is a good thing too.

You'll get a lot of ideas and suggestions here but the best one is to run them 'till they fail and worry about it later. Even with plastic tracks... unexpected things can happen.


HTH






Jeff

yoshigt2

My thoughts exactly Panther, I just would like to know my options early. Essentially I'd like to set the Tammy tank for IR, and just beat the RTR tanks.

Tanker 10

I tried going to the ETO Armor web site to post a link for you but the site appears to be down. A gear box brace gives you more surface area to mount the gear boxes as compared to the stand-offs that come with the kits. Therefore stiffening the hull in that area.

Tanker 10

Tamiya gear boxes are too expensive to replace, at least for me. I would rather spend a little money on preventative measures from the onset.

tomhugill

As long as you're not using geardowns you should be fine, ausfs tiger has survived 10 years punishment in stock form. There's nothing wrong with the Tigers idler system, gearbox brace is a good upgrade though.

Ive found the first gears that tend to go are the brass ones closest to the chrome ones, that's only when I was using gear downs. The stock gearboxes without have always held up fine for me.

ausf

Probably closer to a dozen years now.

That poor Tiger was the training tank for my sons and all their friends over the years. Too many jackrabbit starts to even consider. Still all original, still going strong (original kit tracks too).

I have 5 Tamiyas stretching many years and have only had one gearbox have an issue and that was after my son launched it out of his friend's hand to a 4 foot drop on the sprocket. All it took was a new bearing and to heat and rebound the bent axle and it was back in business.

Tamiyas are expensive, but you get quality components designed to last.

yoshigt2

They do seem much more robust than the HL boxes in my Panzer IV.

It's really nice to hear they will last that long.

So braces at minimum. One more question, I do notice if I let off the throttle in reverse, it will snap to a stop. Going forward it will not. Is there an adjustment I am missing?

ausf

No adjustment. I think you're just experiencing the natural action of the tracks. With prop we tension, the track drapes over the drive sprocket and rests on the second set of road wheels. That slack has to be overcome when going forward, just like the real thing.

If you really want some realism on the way it drives (not recommended for battling), you can install a Turnigy chip in between the MFU and the Rx on the throttle. It sets servo speeds (in both directions) so you can delay the start and stop. It simulates inertia and is fantastic, but really hard to master the driving since the tank will buildup speed on starting and roll out a bit after you release the throttle. It's a real blast, but like I said, not good for battling since you'll over shoot everything or not accelerate as intended. It's complete customizable so you can add as much of the effect as you want.

yoshigt2

Now that sounds like fun. I'd love more realism to it. I'd like to do another Tamiya kit, I kind of prefer them to the Tiagan/HL tanks.

Thanks for all the responses guys! I really appreciate the input!

Any more info on this Turnigy chip?

sevoblast

\Web sight is being worked on and a new web sight is in process. Tiger 1 gear box brace is DP08 but I'll have to check with The Daryl to make sure we have some, they've sold like hotcakes of late. You can email me from my profile on this sight.

yoshigt2

Nice! Thanks!

Panther F

http://www.hobbyking.com/hobbyking/s...regulator.html


It's used primarily on aircraft to control flap movement.

You will have to change your reaction time while using this.




Jeff

Panther F

No one said there was Tom.

Remember it's not a debate or rebuttal. We're just making some pointers there rookie.




Jeff

sevoblast

ETO sight is back up, got hacked again. Also, a new sight is about to go live.

yoshigt2

Thanks for the info.

Any word on the turret weights for the Tiger I? Sorry to ask here.

Panther G

Generally they are not that much more expensive than any other higher end brand. i never paid more than 65.00 for a set and that was new.

Tanker 10

Please share your wealth and tell me where I can buy New Tamiya gear boxes for $65.00.

yoshigt2

Yes. Do share..lol

tomhugill

Jeff an idler upgrade was mentioned in the second post, no need to jump on me....

Jasons store ore has been the cheapest for Tamiya gearboxes I could find, a pair was about £55, so maybe $75-80.

danlrc

[ATTACH]2161759[/IMG]

New approach to gearing.....Belt Drive.
Just one story, but hopefully gives some perspective on gearboxes.

I have a Tamiya King Tiger. It's probably the heaviest Tamiya tank and it has added metal tracks making it all that much heavier. If I remember right, it weighs in at 12lbs.
Shortly after I got it, the main gearbox drive axle broke. It is 8mm in diameter where it enters the wheel, and 6mm in diameter inside the gearbox. But it broke at the c-clip groove, where the diameter is only 4mm! A definite weak spot. Tamiya was great - they replaced the gearbox for free (I had to send receipts, pictures, broken part).

A while later one of the gearboxes stripped a gear. I run "lightly" and not that frequently, and keep the gears clean and lubed with high quality synthetic grease. I bought a new gearbox. A few months ago, another gear stripped. Similar place...on a shaft nearer to the final output. I am NOT buying yet another gearbox.
Instead, I designed a timing belt/pulley drive.

MANY advantages to belt drives - see attachment. The big mechanical advantage is that timing belts engage the pulley at many, many teeth, vs gear trains where only a single tooth engages on each gear. To keep the loads small enough on the single teeth, the Tammy transmission has 8 separate geardown steps, at about an average ratio of 2.2:1 per step. That's what requires all those gears and shafts. A belt drive can do the same reduction easily in just 2 or 3 steps, with no risk of a breaking/stripping a single tooth and ruining the gear box.

I ran bench tests with a mock up drive using belts and pulleys I had, duplicating the reduction ratio of the one good Tammy gearbox I had left.
In the test, I ran 8.0 V to the belt drive set up and dead-lifted increasing weights. At three pounds vertical lift at high speed (a full 8V to the motor), the belt drive lifted with no hesitation and no significant RPM reduction.

Then I switched over and ran the Tamiya drive with the three pound load (exactly the same motor, same battery voltage and same reduction ratio as the belt drive). Yikes! The Tammy drive immediately stripped out. I didn't expect that, so now I have no good Tammy drives (3 stripped ones...anyone want to buy them for parts?).

Bottom line, the new miniature timing belt/pulley designs can handle tremendous loads, have very high efficiency, long life, require no lube or maintenance, are very quiet and easily built, modified and repaired.

More details as I get the parts and do the build. I ordered final parts and will be assembling the KT drive in a few weeks.

I'll be using GT2, 2mm pitch timing belts, 6mm wide with matching pulleys.

Parts for two drives adding up to about $80 from SDP/SI
http://www.sdp-si.com/products/Timin...leys/index.php
I'm looking for a lower cost source, but SDP offers a complete range of pulley and belt sizes needed for custom designs for tank drives.

Tanker 10

Interesting read danlrc, looking forward to seeing your KT run on your drive system.

yoshigt2

This does sound like a nice project. I'm excited to hear how much quieter the electric drive is.