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What transmissions are available for tractor trucks ?

Has anyone used a RC4wd 3 speed ? What are they like ? Has anyone disassembled one, i'm curious to know are they a crash gearbox like the old Tamiya hilux diecast gearbox or are they a dog box like the current tamiya plastic box...??


Also what are everyones thoughts on this 9 speed transmission...?? it has 3 ranges and 3 gears in each range and is full metal...??

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The Rc4wd 3 speed is not the greatest out there. I asked this same question not long ago and it ls said to have some hard shifting issues and the actual shifter is very tight requiring a high torque servo, and it's only 4x4 in first gear and 2wd in all others. With that said their 2 speed and single speed trannys are great but if course not as fun without all the gears.
Pricing also seems a bit steep on it compared to other 3 speeds.

As for the nine speed I've never seen it before so I can't give you any real input on it. Whose the manufacturer of it? And what's the cost?

--Dan

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Hi Dan,
when you say the RC4wd 3 speed has "hard shifting issues" do you mean it is difficult to shift without grinding gears or that it is physically hard to move the shifting mechanism ...?

The 9 speed is made by HGM in Australia.....don't know the cost....is the concept good...??

Thankyou.

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Both, shift shaft is very hard to move requires alot of torque does not feel super smooth and I've heard when shifting it tends to grind if the servo is not setup just right on the shaft (it can be finiky) also with shifting on the fly, but this you'd kind of expect with any trans seeing as they don't have clutches

--Dan

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Do you have a web on HGM?

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I was wondering the same as above do you have a link to the trans maker
Id like to look into a bit more and see what it's all about

--Dan

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No web, but a email: lkhanley@optusnet.com.au

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Hi, email lkhanley@optusnet.com.au , no web address. :)

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I e mailed him and he gave a great response and info. i gave him the forum info and told him to join and share his build. its designed to fit into trucks in replace of tamiya 3 speed.

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Its a shame the didn't make the case look more like a scale engine and tranny combo. Did the email list the gear ratios?

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wow with just a little work that would look just like a engine and transmission lol

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I will post some more pics but motor is inside trany

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This is his e mail to me. i hope he joins or at least tells which forum build is on. Ratios are
high 1st 8.25 2nd 6.83 3rd 5.27
med 13.75 11.39 8.79
low 25.13 20.08 16.06

hope this helps

Hi Don,

The 9 speed was designed to fit into Tamiya a chassis replacing the 3 speed. it is the same overall length as the 3 speed, slightly narrower so it fits in between the rails with ease (unlike the 3 speed) but it is much higher owing to the larger number of internal shafts. It should fit inside a sleeper cab with no problem (with some moving around of radio gear, batteries ect), It will require two servos to shift. Day cabs will require the back wall of the cabin to be cut out so the box can extend trough. How much it extends through depends on where it is mounted on the chassis. if carefull repositioing of the front servos is done and the box moved further forward the transmission can sit in almost the same position as the engine and trans in the full size truck.

As shifting is concerned i would forsee that the 9 speed would essentially be shifted by selecting a range (high, mid, or low) with the right stick on the control in the vertical plane (right horizontal of course being steering) and then shift the gears 1st, 2nd and 3rd as normal with the left stick on the control in the horizontal plane, only changing ranges as the overall situation requires, rather than starting in 1st / low and shifting all the way through all the 9 gears to top. So in some situations you would start in High range / 1st and not even look at the 6 gears below that. In a crawling situation you may decide Low range is suitable and then start in either 1st, 2nd or 3rd and the same for Mid range. Chose a range then choose a gear. Having said that you can also start in low range and shift up through the ranges to high range selecting 1st, 2nd or 3rd at the same time. Almost endless possibilities.



The prototype. A production box would have helical gears on the motor's
primary reduction rather than the spur gears shown here.

The transmissions have a aluminium casing, steel pinions and countershafts, bronze cluster gears, steel syncronizers and more than 20 ball bearings. Supplied with a RS540 or RS555 motor. All gear shifting can be done on the go. Requires two servos to shift. Lubricated by automatic transmission fluid.


Price...???
This is a high end product for the scale model purist, not for the budget modeler....esentially a custom one at at time hand made gearbox. It is not a mass produced off the shelf item. It's cost will exceed the cost of the entire truck x 2. It will however be backed up with individual technical assistance to get each transmission working in the customers vehicle rather than the buy it and go away and die attitude of the manufacturers of the off the shelf gearboxes (which i hear have problems). Cost: $1250.00 AUS. If a customer is unsatsisfied with the transmission i will purchase it back from them for it's original sale price.


The 9 speed at this point is at a crossroads. The developement stage is completed, what is required now is enough interest given the high cost and small market to be shown to justify the expence of getting a large number of gear blanks produced (as the gear cutters have a minimum order number). Currently i have enough blanks to produce only one more transmission. If gear blanks were cut individually this thing would cost a million dollars..

I hope i have been informative.
Please feel free to ask any further questions.


Best Regards
lyle.

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So what are everyones thoughts on the 9 speed transmission..??

Is it a matter of "there is no need for it".....???

That is a dangerous argument, as there is "no need for" almost everything that gets bolted on to a RC truck, like headlights, tailights, sound systems, springs, shock absorbers, smoke generators, mirrors, exhausts, fuel tanks, ect, ect, ect....

Is there anyone that would have one, or will people wait till the big manufacturers offer it, like RC car enthusiasts did with suspension ......???

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This transmission cost 1250 AUS or $ 1347.34 US you can do a 8 speed for about $500 US or a 6 speed for about $355.31 US all aluminum cases and all metal gears. Ed

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Yeah I think the transmissions are one of those things that doesn't translate from the 1:1 to scale modeling. Diesel engines work in a narrow range so the transmissions are geared to keep them working in that range. The electric motors we use provide a lot more range and at small scale you need slow with power so a low gear and a high gear really provide all you need.

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I think the all in one 9s is a great idea, but it's a little on the large side for the guys that want a interior, a day cab, a tipper on the back or other,
If it was smaller/more compact I think there would be a bigger market for the guys that want all those gears and were willing to fork out over a grand for a gear box,
For most people it would come down to cost, how much room it takes up as there are alot of cabs out there that are crammed with electrics when the body is off and for most a 3 speed is plenty...
Just my thoughts...

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You are quite correct.
The RS540 is quite a broad range and torquey motor.
If someone was seeking scale realism in perfomance (as many do in railroad models) a electric motor of narrower performance range could be selected to simulate the diesels performance. Perhaps the RS555. It is likely that such a motor would draw considerably less amperage than the average RS540 so far greater running times may also be achieved along with the more realistic performance.

It would be a matter of individual taste....

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Thankyou for your thoughts on the matter.

Many things do not go from 1:1 down to scale. This is a real problem. this is why the trans is a lot larger than a scale model of a real trans would be. The gears inside are around Tamiya size. And there are a number of technical reasons why Tamiya went for that size of gears.
If you did a scale model of a real trans the gears and shafts would be tiny. It would be like watch making, it would be fragile and prone to breakage and bearing failures and the gears being so small would need to hardened steel and then ground...
OMG....if you think 1300 bucks is over the top, a minature scale gearbox with tiny hardend and ground gears would cost more than the national debt....

This monster 9 speed can be mounted further forward in the chassis with some inginuity reducing the overhang at the rear of a day cab to 1/2 inch.

Everything in engineering is a compromise, what one person will trade off another won't.....As i say it is a matter of individual taste...

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Size comparison:....

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Impressive, but totally overkill. I like it! None the less, I just don't see any need for 9 gears. Three seems about right, and when I had a 3 speed truck, I found myself most often running in 2nd gear. It was a good in between gear. Now my latest truck has a really simple one speed planetary gear head motor and that doesn't bother me one bit. It's more compact, stronger, and can handle all kind of torque. Yes, I gave up shifting the gears, but that's one less thing to worry about, it frees up a channel on my radio, and I just never found myself shifting gears all that much anyway. It's fun for a little while, but if your driving your truck in a tight place, about the only place you do get up to top speed is in an open parking lot. Unless you've got some aux. gear reduction.

I wonder how much backlash that 9 speed has. Tamiya's 3 speeds have way to much.

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With metal gears and synchronizers backlash can be dramatically reduced because the slots in the gears and the drive dogs on the sychronisers are cut into a solid blank and can be made any size.

The plastic gears and sychronisers Tamiya use are injection molded and cross sections of injection molded items must be kept thin or the plastic will shrink considerably when it cools. Therfore the drive dogs on the synchronizers are narrow and the slots in the gears are wide (the land in between the slots is narrow). Resulting in lots of backlash....

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9 speed alternate mounting positions..

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by the time you shift thru all 9 gears, it will be across the stateline.:D

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Even with these pics you can see its nearly impossible to have an interior, especially in a day cab. I really dont even see a way in a conventional or an extended sleeper without figuring out a way to lay it on its side.

--Dan

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I will have to say having a interior was not a priority when designing this transmission. For me personally it is not a priority at all. I don't see the need to make the cab comfortable for a 5 inch hight plastic man. The cab interior is far better utilised for equiptment. If cab interiors are a priority it may be more suitable to build a static model.

The transmission connot be laid on its side. It contains automatic transmission fluid. It would make a awfull mess, not to mention oil up the motor......

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It would not allways be necessary to shift through all 9 gears.

As shifting is concerned i would forsee that the 9 speed would essentially be shifted by selecting a range (high, mid, or low) with the right stick on the control in the vertical plane (right horizontal of course being steering) and then shift the gears 1st, 2nd and 3rd as normal with the left stick on the control in the horizontal plane, only changing ranges as the overall situation requires, rather than starting in 1st / low and shifting all the way through all the 9 gears to top. So in some situations you would start in High range / 1st and not even look at the 6 gears below that. In a crawling situation you may decide Low range is suitable and then start in either 1st, 2nd or 3rd and the same for Mid range. Choose a range then choose a gear. Having said that you can also start in low range and shift up through the ranges to high range selecting 1st, 2nd or 3rd at the same time. Almost endless possibilities.

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I am working on a Cat V8 engine cover to go over the front of the transmission to improve the engine bay looks.

This is the extension through the front firewall into the engine bay with the 9 speed moved forward.

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One difference between 1:1 and our equipment is the prime mover RPM. Diesel engines have a very narrow power band and low max RPM, requiring multi-gears to match available power/torque and road speed. Our electric motors have a considerably wider RPM range, depending on turns, etc. I chose a low RPM 85t motor for my Payhauler. It turns 5200 RPM at 7.4V, so is about double the diesel engine RPM in the real truck. By using a 3-spd trans, I just about replicate prototypical road speed, since the 1:1 had a 6-spd trans. Lower turn motors spin a lot more RPM, reducing the actual need for a many-gear trans - use of one speed or a 2-spd trans works just fine since we seldom see anything like scale speed (70 MPH) with our trucks.

But then, nothing beats shiftin' those cogs 9 times going across the room! To each his own - just have fun doin' it.:p:p

Ken

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Yes Ken.....you got it...... to each his own...!!

I've been experimenting with 12volt RS555 motors running on 7.2 volts.
In that configuration they act more like the diesel, it's more of a challenge to drive, and more realistic, they drive like a truck instead of a sports car.....the spin off is the batteries last for ages...

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Here is the gear ratio chart for anyone interested.