ETO Drive for KT - report
08-07-2016, 06:01 AM
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ETO Drive for KT - report
After going thru 3 Tamiya gearboxes over the years - a broken axle and then stripping two gearboxes (I think my KT may be too heavy for the stock gearbox), I started experimenting with timing belt drives. The net with that approach was that under heavy load, the belt over the small diameter main axle drive sprocket would jump teeth. No-go on that approach for now.
So I bit the bullet and bought the ETO drive. Pretty much perfect....should have done it long ago.
Details:
My KT has heavy metal tracks (3.48 lbs) and a lot of animation additions (smoker, lights, BP canon, etc) that make it heavy - 13.4lbs with battery pack.
The new drive was shipped immediately on order and I had it in just 3 days...super-quick delivery!
First observations -
This thing could probably handle a golf cart. Really heavy duty.
And at first, it seemed really heavy....it weighed-in at 1.5 lbs. But for comparison, the Tammy drives together are up at 1.12 lbs. Since my KT is already heavy, I lightened up the ETO drive frame with a bit of drilling and trimming (see pics). The changes took off 0.23 lbs. The new weight of the ETO unit is 1.27 lbs., only 0.15 lbs (2.4oz) heavier than the Tammy drives it replaces - not of much consequence. The lightening is not necessary - I just can't resist changing stuff.
No directions were included (correction: full instructions were emailed, but I didn't see the email), but with just a little mechanical common sense, none are needed. The space between the bearing blocks is very tight. I didn't use the included brass axle spacers - they were slightly too long to fit. The bevel gear width alone on the axle seems to give very acceptable gear mesh, but with no spacer, degree of over-mesh is uncontrolled. Any feedback on that?(correction: after seeing the instructions, its clear how the spacers fit. Now they are installed and all fits exactly)
The bevel gear set screws all need to have threadlock applied. During adjustment runs, they kept coming loose. Threadlock was also used on the 4 mounting bolts. No problem once threadlock was used. (also in the instructions that I missed seeing) A minor quibble - even though the bevel gears are all the same size, the setscrews on the motor gears and shaft gears are different sizes, so two different tools are required.
The unit is super quiet compared to the Tammy drive, and very smooth. Top scale speed in testing was 22 mph (at 7.6volts). I think prototype sustainable top road speed was 24mph and 12mph cross country, so the ETO drive is pretty much right on the money for the KT speed.
The other big noticeable difference was that handling in forward and reverse turns is much smoother and very predictable at stock transmitter settings. To get reasonable turn performance with the Tammy drives I had to play with transmitter servo speed and expo settings. Two things helped here I think. The power and efficiency of the new drive and the modification to the tracks suggested by wright971 (see his post: http://www.rcuniverse.com/forum/rc-t...l#post12241483 )
As wright971 suggested, I beveled off the shoulders of the tracks using an alignment jig on a bench sander. Really seems to help a lot.
The slight extra weight seems no issue - the tank sits and rides level and looks good rolling over obstacles. I did remove and twist the two leading wheel (behind drive wheels) torsion bars to pre-load the wheels to support any effect of extra weight.
I don't have run time or amp data yet, but in doing install and running tests, a 6 year old NiMH C-cell pack (7.2V, 5000mAh) seemed to hold voltage very well under load and run for a seemingly long time.
Bottom line - maybe a bit costly, but in the long run and for performance: priceless. Highly recommended.
So I bit the bullet and bought the ETO drive. Pretty much perfect....should have done it long ago.
Details:
My KT has heavy metal tracks (3.48 lbs) and a lot of animation additions (smoker, lights, BP canon, etc) that make it heavy - 13.4lbs with battery pack.
The new drive was shipped immediately on order and I had it in just 3 days...super-quick delivery!
First observations -
This thing could probably handle a golf cart. Really heavy duty.
And at first, it seemed really heavy....it weighed-in at 1.5 lbs. But for comparison, the Tammy drives together are up at 1.12 lbs. Since my KT is already heavy, I lightened up the ETO drive frame with a bit of drilling and trimming (see pics). The changes took off 0.23 lbs. The new weight of the ETO unit is 1.27 lbs., only 0.15 lbs (2.4oz) heavier than the Tammy drives it replaces - not of much consequence. The lightening is not necessary - I just can't resist changing stuff.
No directions were included (correction: full instructions were emailed, but I didn't see the email), but with just a little mechanical common sense, none are needed. The space between the bearing blocks is very tight. I didn't use the included brass axle spacers - they were slightly too long to fit. The bevel gear width alone on the axle seems to give very acceptable gear mesh, but with no spacer, degree of over-mesh is uncontrolled. Any feedback on that?(correction: after seeing the instructions, its clear how the spacers fit. Now they are installed and all fits exactly)
The bevel gear set screws all need to have threadlock applied. During adjustment runs, they kept coming loose. Threadlock was also used on the 4 mounting bolts. No problem once threadlock was used. (also in the instructions that I missed seeing) A minor quibble - even though the bevel gears are all the same size, the setscrews on the motor gears and shaft gears are different sizes, so two different tools are required.
The unit is super quiet compared to the Tammy drive, and very smooth. Top scale speed in testing was 22 mph (at 7.6volts). I think prototype sustainable top road speed was 24mph and 12mph cross country, so the ETO drive is pretty much right on the money for the KT speed.
The other big noticeable difference was that handling in forward and reverse turns is much smoother and very predictable at stock transmitter settings. To get reasonable turn performance with the Tammy drives I had to play with transmitter servo speed and expo settings. Two things helped here I think. The power and efficiency of the new drive and the modification to the tracks suggested by wright971 (see his post: http://www.rcuniverse.com/forum/rc-t...l#post12241483 )
As wright971 suggested, I beveled off the shoulders of the tracks using an alignment jig on a bench sander. Really seems to help a lot.
The slight extra weight seems no issue - the tank sits and rides level and looks good rolling over obstacles. I did remove and twist the two leading wheel (behind drive wheels) torsion bars to pre-load the wheels to support any effect of extra weight.
I don't have run time or amp data yet, but in doing install and running tests, a 6 year old NiMH C-cell pack (7.2V, 5000mAh) seemed to hold voltage very well under load and run for a seemingly long time.
Bottom line - maybe a bit costly, but in the long run and for performance: priceless. Highly recommended.
Last edited by danlrc; 08-10-2016 at 05:36 AM.
08-07-2016, 08:08 AM
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Very nice write up. I see what appears to be stand offs under the plate. Do you use them when mounting the gear boxes, or can the gear boxes be set right onto the hull floor? If so, that would be a good stiffening option.
08-07-2016, 09:29 AM
#4
Great review. Very informative and well written. Just one thing I'm left wondering about - How much did it cost, delivered to your door? Shipping to Detroit should be about the same as to Minneapolis.
Also, what brand is your KT? I get the impression it's a Tamiya, but would like to be sure. I'd like to get a Tamiya Tank and I've been looking at the new JP4 but the KT is also in the running.
Also, what brand is your KT? I get the impression it's a Tamiya, but would like to be sure. I'd like to get a Tamiya Tank and I've been looking at the new JP4 but the KT is also in the running.
08-07-2016, 01:11 PM
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But the 4 point mount is plenty strong because unlike the Tamiya with separate right and left drives, this is one single unit - both axles in perfect, rigid alignment on a rock solid metal base. No flex can occur. The load on the floor pan is that of the track tension, and the 4 bolts are more than enough to hold the drive in place.
08-07-2016, 01:29 PM
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You're welcome. Here are some old often repeated clips...
I'll try to do more soon.
https://youtu.be/MWSXFVleYHw
https://youtu.be/EAaeK9gbNu8
https://youtu.be/whRuQ3Dlwu8
I'll try to do more soon.
https://youtu.be/MWSXFVleYHw
https://youtu.be/EAaeK9gbNu8
https://youtu.be/whRuQ3Dlwu8
Last edited by danlrc; 08-07-2016 at 01:35 PM.
08-07-2016, 01:33 PM
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Great review. Very informative and well written. Just one thing I'm left wondering about - How much did it cost, delivered to your door? Shipping to Detroit should be about the same as to Minneapolis.
Also, what brand is your KT? I get the impression it's a Tamiya, but would like to be sure. I'd like to get a Tamiya Tank and I've been looking at the new JP4 but the KT is also in the running.
Also, what brand is your KT? I get the impression it's a Tamiya, but would like to be sure. I'd like to get a Tamiya Tank and I've been looking at the new JP4 but the KT is also in the running.
Cost was as listed on website...$265. Shipping was only $12 - super reasonable for 3 day USPS delivery service.
08-07-2016, 02:47 PM
#9
You're welcome. Here are some old often repeated clips...
I'll try to do more soon.
https://youtu.be/MWSXFVleYHw
https://youtu.be/EAaeK9gbNu8
https://youtu.be/whRuQ3Dlwu8
I'll try to do more soon.
https://youtu.be/MWSXFVleYHw
https://youtu.be/EAaeK9gbNu8
https://youtu.be/whRuQ3Dlwu8
08-09-2016, 05:28 PM
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Hey Sollie....here's the ETO tranny running....boring, but gives an idea of how smooth it is.
Recording sound level was not changed. At first, you hear a lot of clatter from the spinning metal tracks (the tank is on a test stand). You can't hear the drive...it's very quiet.
Later in the vid, I turned up the tank sound to about 75%. It totally drowns out the drive sound.
Still a lot of grease on the axles, etc that I cleaned up before closing things up. The only exposed gears are the bevel sets. I covered those with strips of wide masking tape across the gearbox frame. Very easy to keep dirt out and grease in.
Note that with tnhis gearbox, it seems expensive, but you don't need to beef up the chassis, add support bearings on the output shafts, etc etc....so you don't have to spend money on Band-Aid fixes to the Tamiya gearboxes.
See next vid I post. This tank weighs almost 14 pounds, has heavy metal tracks, but the drive just pounds away thru tall grass and up a 45deg bank with no sweat.
https://www.youtube.com/watch?v=aohDUg2YYJY
Recording sound level was not changed. At first, you hear a lot of clatter from the spinning metal tracks (the tank is on a test stand). You can't hear the drive...it's very quiet.
Later in the vid, I turned up the tank sound to about 75%. It totally drowns out the drive sound.
Still a lot of grease on the axles, etc that I cleaned up before closing things up. The only exposed gears are the bevel sets. I covered those with strips of wide masking tape across the gearbox frame. Very easy to keep dirt out and grease in.
Note that with tnhis gearbox, it seems expensive, but you don't need to beef up the chassis, add support bearings on the output shafts, etc etc....so you don't have to spend money on Band-Aid fixes to the Tamiya gearboxes.
See next vid I post. This tank weighs almost 14 pounds, has heavy metal tracks, but the drive just pounds away thru tall grass and up a 45deg bank with no sweat.
https://www.youtube.com/watch?v=aohDUg2YYJY
Last edited by danlrc; 08-09-2016 at 05:31 PM.
08-09-2016, 07:11 PM
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Here's a vid of the KT making the first run with the ETO drive in heavy grass. Shaky/jumpy...doing phone video and running Tx....sorry.
Tank weighs almost 14 lbs. Has metal tracks. It ran with no effort thru heavy grass and up a bank. The bank is more than 45deg and the tracks lose traction, but the drive keeps cranking away.
Turns, handling all better than I remember having with the Tamiya gearboxes.
I think the ETO is a winner.
https://www.youtube.com/watch?v=7O4FFhtwmJo
Tank weighs almost 14 lbs. Has metal tracks. It ran with no effort thru heavy grass and up a bank. The bank is more than 45deg and the tracks lose traction, but the drive keeps cranking away.
Turns, handling all better than I remember having with the Tamiya gearboxes.
I think the ETO is a winner.
https://www.youtube.com/watch?v=7O4FFhtwmJo
08-09-2016, 11:53 PM
#12
Dan, thanks for your compliments on the transmission. Normally detailed instructions are sent including about loctite on the gear set screws but they must have ended up in your spam folder, they were sent 01 August.
With my units gone are the transmissions stripping a gear if debris gets in the tracks, now you will break a track link. Last time I looked a track link is a bit less expensive than a Tamiya overhaul kit, which is the only way to get parts for Tamiya transmissions. You will also find that when battling you will have maneuverability until the killing hit. Since back when I was battling at Danville I seemed to be a bullet magnet the maneuverability while taking hits is a big plus for me.
With my units gone are the transmissions stripping a gear if debris gets in the tracks, now you will break a track link. Last time I looked a track link is a bit less expensive than a Tamiya overhaul kit, which is the only way to get parts for Tamiya transmissions. You will also find that when battling you will have maneuverability until the killing hit. Since back when I was battling at Danville I seemed to be a bullet magnet the maneuverability while taking hits is a big plus for me.
08-10-2016, 05:09 AM
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Note - I edited the original report post to correct for my failing to see instructions...
Last edited by danlrc; 08-10-2016 at 05:38 AM.
08-10-2016, 05:26 AM
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http://www.rcuniverse.com/forum/rc-t...l#post10247842
Based on a small motor found in a surplus store.
Speed is totally adjustable by resistor value controlling voltage to motor. Is this KT turret too fast? I think I remember looking up prototype turret speed and tried to match it.
The one time I was at Danville (wish I could go again...fantastic...great people), I was surprised at how fast some tanks and turrets were. That was years ago though.
Edit: Hi Benny...checked T2 turret speed references. There were 4 speeds for a full rotation - 60sec low, 19 sec high, 10 sec high at hi engine RPM, and manual (720 handwheel turns per rotation). The model rotation time is about 13 sec, slower than the max prototype speed of 10 sec.
Final turret aiming was done with the handcrank.
Note that a rotary connector was used on wires to the turret....a great modification. No worry about twisted wires anymore....
Last edited by danlrc; 08-10-2016 at 06:15 AM.
08-10-2016, 05:34 AM
#16
Hey, "TANKS" so much for taking the time with the report AND videos! These gearboxes from Krasnodar Krai are top notch and such a simple design. Being quiet is what I'm all about and just wish I had the $$$ for a set in this Jagdpanther build... if they're available yet.
I spent many hours with my IMPACT unit for my Panther G just to make them this quiet and still don't have nearly the gearbox. I do have a TII build coming up later and this thread here proves they are the number one upgrade for a tank.
That is if you're serious enough.
Jeff
I spent many hours with my IMPACT unit for my Panther G just to make them this quiet and still don't have nearly the gearbox. I do have a TII build coming up later and this thread here proves they are the number one upgrade for a tank.
That is if you're serious enough.
Jeff
08-10-2016, 06:51 AM
#17
Turret drive mods shown in this post:
http://www.rcuniverse.com/forum/rc-t...l#post10247842
Based on a small motor found in a surplus store.
Speed is totally adjustable by resistor value controlling voltage to motor. Is this KT turret too fast? I think I remember looking up prototype turret speed and tried to match it.
The one time I was at Danville (wish I could go again...fantastic...great people), I was surprised at how fast some tanks and turrets were. That was years ago though.
Edit: Hi Benny...checked T2 turret speed references. There were 4 speeds for a full rotation - 60sec low, 19 sec high, 10 sec high at hi engine RPM, and manual (720 handwheel turns per rotation). The model rotation time is about 13 sec, slower than the max prototype speed of 10 sec.
Final turret aiming was done with the handcrank.
Note that a rotary connector was used on wires to the turret....a great modification. No worry about twisted wires anymore....
http://www.rcuniverse.com/forum/rc-t...l#post10247842
Based on a small motor found in a surplus store.
Speed is totally adjustable by resistor value controlling voltage to motor. Is this KT turret too fast? I think I remember looking up prototype turret speed and tried to match it.
The one time I was at Danville (wish I could go again...fantastic...great people), I was surprised at how fast some tanks and turrets were. That was years ago though.
Edit: Hi Benny...checked T2 turret speed references. There were 4 speeds for a full rotation - 60sec low, 19 sec high, 10 sec high at hi engine RPM, and manual (720 handwheel turns per rotation). The model rotation time is about 13 sec, slower than the max prototype speed of 10 sec.
Final turret aiming was done with the handcrank.
Note that a rotary connector was used on wires to the turret....a great modification. No worry about twisted wires anymore....
08-10-2016, 07:31 AM
#19
Very sorry, Bob. The email instructions look great, but I totally missed seeing them. Good news is that install was so straightforward I eventually got TU installed without even seeing the instructions.
Note - I edited the original report post to correct for my failing to see instructions...
Note - I edited the original report post to correct for my failing to see instructions...
08-10-2016, 07:39 AM
#20
Hey, "TANKS" so much for taking the time with the report AND videos! These gearboxes from Krasnodar Krai are top notch and such a simple design. Being quiet is what I'm all about and just wish I had the $$$ for a set in this Jagdpanther build... if they're available yet.
I spent many hours with my IMPACT unit for my Panther G just to make them this quiet and still don't have nearly the gearbox. I do have a TII build coming up later and this thread here proves they are the number one upgrade for a tank.
That is if you're serious enough.
Jeff
I spent many hours with my IMPACT unit for my Panther G just to make them this quiet and still don't have nearly the gearbox. I do have a TII build coming up later and this thread here proves they are the number one upgrade for a tank.
That is if you're serious enough.
Jeff
http://www.etoarmour.com/product_det...?productID=S03
Krasnodar Krai is beautiful, and quiet.
08-10-2016, 08:29 AM
#21
Dan great video. Looks like you were doing a re-inactment from "Battle of the Bulge" when the Tiger II (M-47) tracks start to slip while climbing the hill towards the fuel depot!!!
08-11-2016, 08:16 AM
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Smoke is not cg. It's a small black powder cartridge electrically fired. The barrel is set up to fire the BP cartridge, or to have a flash LED module inserted for battling.
I'm close to finishing a prototype design with LED flash and fog juice smoke. It could be fired many times with no reload. Stay tuned....
I'm close to finishing a prototype design with LED flash and fog juice smoke. It could be fired many times with no reload. Stay tuned....
08-11-2016, 09:02 AM
#25