1/16th scale radio-controlled Komatsu D455A-1

[tournaphil]

We've started the fifth machine, the Komatsu D455A-1 radio controlled. This machine is approximately the same size as the 41's, in fact, it knocked the 41 off its perch as the largest on the market at the time. It will be an approx 1500 s/n machine from 1986 and will be modelled from the same machine featured in PA Minings youtube documentary video of the D455A-1 shown here. The D455A-1 was considered to be the 1st Super Dozer placed on the commercial market, as mentioned by PA Mining.



This is the 1:1 machine we will build, a 1986 Komatsu D455A-1 with full-U blade and 4-barrel Super Ripper. This photo is from P.A Mining's documentary video to show the machine.(Photo courtesy P A Mining.)

Progress report: Progress to date is the grousers are done and ready to bolt to the chains.

 

[tournaphil]

We've been busy on the D455A. Drawings are completed and all the parts have been acquired or laser cut in mild steel. Like the previous models, this is an industrial model using industrial components. The motors are F350 window winder motors geared down at 4:1 chain driven to the final drive 5/8" dia final drive shafts which are keyed to the drive sprockets. Unlike the 1:1, we are not expecting any final drive problems. Here are some build update photgraphs.



Tracks completed. Everything starts with the tracks accurately built, laid out and to scale.



Next stage is to make a mockup, very importantly, sitting on finished tracks and rolling gear. This is just like the auto manufacturers used to do. As redimentary as it looks here, it's vital to get the dimensions right at this point along with the drawings before committing $$ to the steel supplier and laser cutter.



Test frame with motors and rolling gear fitted to prove the drawings before committing to laser.


Some of the detailed laser cut parts prepped for the welding bay.

 

[tournaphil]

Some more progress pics of the D455A-1. Note this is a + 1500 serial number machine like the machine in the first photo by PA Mining.


The main frame tub and track frames mig-welded. Very strong, a good rigid base for the model with plenty of frame strength to hang the U-blade and ripper.



While waiting for the laser cutters I build the cab for the EROPS.



Basic frame welded

 

[tournaphil]

We got the U-blade sheets rolled by a sheet metal company in a set of slip rollers. They did a good job, pulling those three-radii tri-planar curves into the end sheets and two radii into the center sheet. They are just propped up here, they align nicely and we'll tig-weld them in the backsides.



Tilt cylinder I spun up on the lathe. The full U has one tilt cylinder and one tilt brace.

 

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20' U Blade has been welded. Good strong mig-welds here. They'll dress up nicely leaving a rough worn appearance.


U blade rough finished. Ground engaging not fitted yet. Looks like it has already spend 10,000hrs on the job.


Made the rops to dimensions from the parts manual in 1:1 balsa to check fit. Next I'll make it in resistance welded tube and it will be all welded with mounts. Most of the parts here I have made are drawn in a drawing program using the OEM parts manual as a guide. Unlike the Caterpillar parts books of which many are engineering drawings and can be scaled straight off, the OEM Komatsu manuals as are the Fiat-Allis and Allis-Chalmers manuals, reasonably accurate drawings but not acurately to any scale. So they are a good guide but require a complete redraw for use in building. So in making something like this, it is essentially back to square one and start from scratch for the drawings.
I've seen a few drawings in 3D programs on the internet however, they are of no use in building an actual working model without a massive redraw in CAD, nothing connects and the material thickness is simply a drawn line. That's a huge headache. So I don't use CAD, we can roll our own in half the time and just as good or better using 2- dimensional drawings and some good ole metal work on the work bench in way less time than it takes to fiddle around in a tricky CAD program. I did use CAD for the CHTZ T-800 though. Once was enough, more time was spent in CAD than at the workbench, back to the tried and true drawing with a calculator and basic 2-dimensional drawing program and some good ole marking and scribing tools.



Here's the D455A-1 and the HD-41. They are basically the same size machine and use the same engine, a Cummins V1710-C-700. The HD-41 uses a Twin-Disc trans and the D455A uses a pair of D355A trans mounted side by side in the one case. The D455A is a little heavier by about 10 tons depending on mounted equipment and just a little longer in the main frame and track frames. U-blades for both are 20 feet wide.

 

[tournaphil]

Single tine Super Ripper draft frame completed. It will have both lift and ptich rams. Since this machine is the predecessor to the prototype D555 which became the D575A-2, I will use the same rams as I did on the D575A-2 model.

 

[tournaphil]

Here we have the D455A-1 set up just for obtaining and measuring some positional dimensions like setting the distances for the blade lift rams, tilt cylinder and the ripper lift and pitch barrels before I go ahead and make them. I'm going to have to spin those up on the lathe so it will be a while yet before I can get back on it. The barrels for the lift rams are already done. It's weighing in at about 29lbs at this point for the bare tractor which scales out in 3 dimensions at 1/16th scale to approx 117,000 lbs for the bare tractor scaled back up to 1:1. The U-blade weighs in at 27,000lbs and the ripper at 14,000lbs on the 1:1. So for a 1:1 machine we are looking at about 166,000 lbs with fluids, full U and super single. At 29lbs for the bare model tractor at 1/16th we are looking for another 11lbs in weight with the blade and ripper and finishing touches for it to scale out at approx 166,000lbs in the 1:1. We know the blade, draft arms and ripper box weigh 9lbs at 1/16th so its getting very close to scale in weight. There's not a lot in terms of weight to be added to it taking into account all the above.There's an awful lot of detailing work to go in yet though, this is just the basic fabrications.

 

[tournaphil]

Another progress report on the D455A.



The Komatsu K-Link type diagonal bracing is fabricated and fitted up and adjusted for the correct side-load transfer and tilt. The Komatsu K-Link with the three ball-joints on the bar that connects the front ends of the draft arms allows for tilting of the blade without bending or twisting the draft arms and transfers side loading stresses to the opposite side of the machine to prevent the machine pivoting on the loaded corner of the blade since the loading is partially transfered to the opposite side by the manner in which those braces and ball joint work in unison with one another. This 1:1 machine does not have two tilt cylinders, you'll need a totally different linkage arrangement for that. Of course a full-U blade is not a severe service blade like a reinforced straight tilt blade like on the D575A-2 model; first and foremost a full-U blade is a mass material moving implement.


Another view of the Komatsu K-Link arrangement. You can see the three ball joints mentioned earlier.


Progress to date. The ripper beam or drawbar is cut and ready for drilling and mounting to the tractor ripper frame and the ripper box already made. The pick is also made and I should have it all on this week.

There is a ton of electronics to go into this project yet. We got our motor controllers from Dimension in Ohio. They work flawlessly and if we have had a problem Dimension have always come straight to the party and fixed it plus they carry parts and have a service dept. Real service and parts back up. And then we have all the programming to make them do the various cycles autonomously while we sit on the side line with a coffee and watch them.

 

[tournaphil]

Progress update: The rops is made from some nice resistance welded tube and tig-welded. The ripper draft beam is also made and I am currently making the track frame covers. All the parts for the blade and ripper lift and pitch rams are made - soon as the track frame covers are made we'll fit them up. The paint at this stage is just left overs rough sprayed on to stop surface rust formation until I sand and fill and undercoat, resand and refill and prime all the fabrications together. We have the top coat yellow, Komatsu Dark Yellow which is the correct color for the Komatsu's built in the 1970's and 80's.

 

[tournaphil]

Progress update: The ripper drawbar beam is made and test fitted and the lift and pitch rams will be made next week.



We assembled the tractor so we could get the blade lift rams fitted up and tested and make sure the lift rams and tilt ram working through the adjustable K-Link and diagonal braces tilted the blade freely without twsiting as is the Komatsu design. Works exactly as the design intended.
Rops and cab is also finished.

Compare this photo with the first photo from P.A Minings photo in the beginning of the thread.

So this week we expect to have the ripper lift and pitch rams made then move on to the panel work such as track frame covers, engine side panels, hydraulic tanks and a myriad of detail work such as air intakes, exhaust and of course the electronics. Some questions have been asked about the 1500 serial number mentioned in the first introduction of the build. D455A-1's began at s/n 1001. So a 1500 s/n machine indicates approx 500 may have been built to get up to a 1500 s/n number machine though that would have to be checked against the Komatsu s/n book by someone.

 

[tournaphil]

"D455A-1's began at s/n 1001." And thats even just my guess since Komatsu seem to have begun s/n's for their machines at 1001. I have no proof they did not start D455A-1's later at say 1011 etc etc for example. The 1500+ s/n machines underwent some major cosmetic changes like the hex cab for example and the machine began morphing into the prototype D555A.

 

[tournaphil]

Ripper lift and pitch rams fitted up and tested.

 

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Current progress pic. Track frsame covers and panel work is next.

 

[farmerlund]

Pretty interesting build. How do you make the track pads? I really like the way you make it look used. How many hours do you think it took you to build it?

 

[tournaphil]

Pretty interesting build. How do you make the track pads? I really like the way you make it look used. How many hours do you think it took you to build it?

The grouser plates are cast zinc, then the four holes for the grouser bolts are drilled in a jig and bolted to the track chains. It just looks used at this point since the paint is currently only to prevent flash rust to worked steel surfaces as mentioned earlier. There would be about 1000 hrs labor in each of the dozers built.

 

[tournaphil]

We got the track frames and front idler recoil all fitted up and the track frame covers made and bolted up. The recoil is functioning nicely with enough sag in the chains like the 1:1 but not taut - enough to roll freely and not throw a track.

 

[Tyler d4c]

Would you be interested in building a machine for hire

 

[tournaphil]

Would you be interested in building a machine for hire

Sorry, that's not something we do. Thanks for the inquiry.

 

[tournaphil]

More progress on the D455A. A lot of finishing work and painting is done. The electrics were installed including the H-bridge motor controllers and the wiring looms made up and installed along with the radio control gear. We field tested the bare tractor rolling frame for the first time under it's own power and radio control. Purpose was to run it hard on some rough 30deg side slopes executing turns in both directions on the side slopes and backing up across the slopes to check the tracks and rollers for operatiion and alignment and see if it would throw a track. Of course a big tractor like this in 1:1 is usually kept pretty much on the flat however we needed to stress and observe the rolling gear before moving to the next step. No problems so we pulled it down and began painting for re-assembly. We've got the decals all made, engine bay side covers are made and we are just about ready for assembly and super detailing such as grab rails decals, air cleaner barrels etc.
Here are some progress pics.


Blade and ripper frame


Main frame and ROPS


Track frames

 

[tournaphil]

Correction:
I wrote in my post #5 that the D455A-1 and the HD-41/41B use the same engine, a Cummins V1710-C-700. The D455A-1 uses the Cummins V1710-C-800 engine rated at 650hp in the D455A-1. Thanks for the info bigiron.