[1:8] Akerman H16D

Hello Everybody.

It's time for me to start my very first buildthread.

I have since 2004 been building on an Akerman H16D excavator in 1/8 scale but since 2006 the build has been more or less standing still due to circumstances like buying a house and getting kids.

From the beginning my excavator was decided to be powered by a gasoline engine and the tracks and swing moved by homebuilt hydraulic motors. Since then I have realized that using a gasoline engine is associated with a lot of problems like like heat and vibrations. Building your own hydraulic motors is very complicated and timeconsuming, time that I don't have any more.

A while ago I decided to make a major change in the design. After reading a lot of interesting posts here in this forum I have decided to make my excavator to run from electric mortors.

So far I have decided to use a Jung IPZ 1 - HR 7 hydraulic pump powered by probably a Torcman motor. I have thoughts of using Veroma hydraulic valves but I'm not sure about that yet, maybe i build my own valves and just buy the pressure relief valve.
For the undercarriage I'm thinking of Graupner Speed 600 to power the tracks but I need to find a suitable reductiongear, preferably a planetary gear with a reduction ratio of about 30-50:1

Here is a few pictures from the build so far.

Hello Laban,

great job! The hydraulic pump is certainly the right one and as far as I know the Veroma-Valves are good ones.
Which voltage do you want to use? 12 Volts? I think, that the Graupner Speed 600 are to fast, this will need a bigger gear reduction. Probably you will need about 15 Revs on the chainwheel. Where do you want to place the Motors? Planetary gears from cordless drill´s are often used, the end reduction happens inside the chainwheel with a homemade planetary gear.
By the way, in my actual project I use a final gear reduction in the chainwheel 20.36:1, using a double planetary gear. Reduction over all is 582:1.

greets
Markus

This looks great!

AFAK, Speed 600 come in various speeds and not all of them are racing motors - I think one even has a 5-pole rotor?
But maybe it would be an idea to use brushless outrunners?
Several people have used them successfully.

that´s why I asked for the Voltage. There are several Speed 600, but only one for 12V and another one for 14.4V. Feel free, to take a look on the Graupner-Motoren.pdf, specially side 7.

The voltage range includes higher voltages for several motors.
AFAIK, the "Nennspannung" is mainly intended for direct drive airplanes - with gearing, higher voltages can be used. (Although that means even higher speeds, so your original point stands.)

Yes I will use 12V and the idea to use the Speed 600 BB Turbo from graupner is "stolen" from Bernd Hellers EC300 and I'm sure I have read somewhere that he is using 36:1 planetary gear as the first step in the reduction. The Speed 600 is running at 18200rpm under no load wich is quite high, I have not been able to find the rpm under load but my guess is that it would be around 16000rpm.
I'm aiming at a trackchainwheel rpm of 10-15rpm where 15rpm is an absolute max, I want my model to be quite slow.
My first thoughts was to use the Comodrills MFA motors as they come in a wide range of different reductions but I think they are too weak. I have seen them beeing used for the swing in 1:14,5 excavators ,here in the forum, and then used in pairs.
I'm open for the idea to use brushless motors to drive the tracks too.

My track motors will be placed in the square compartment under the slewing ring and drive the tracks by a chain.

Is it possible to use the Veroma valves with a higher preassure than the 30bars stated on their homepage, I will use 35-40bar.

Gruß
Anders

Hello Anders,

I`m gonna use the Robbe Roxxy Outrunner 2827-34 Brushless, which makes about 760Turns/Volt, also using 12 Volts. I´m not sure about the load-rpms, but I think it should be round about 7000. I will locate the Motors in the sidebeams of each track (Liebherr 984, 1:10), so it will certainly fit in the under-carriage middle section of your Akerman. As your Model isn´t as heavy as mine (once if it´s finished), I even would say, they´re a little bit oversized!
Because of the brushless Motors uses three wires each, you need a rotary union with six electric circuits or you use a second receiver and an accu in the under-carriage for driving.

greets
Markus

I have been stuck looking for a suitable Cordless Screwdriver in my search for a planetary gear to use for the track drive. Finnally after taking 4!!! different screwdrivers apart I have found what I been looking for - woohoo. I'm going to follow Kette1zu8's tip and use Robbe brushless motors for the tracks.
I the meantime I have been doing some work on the drivers cab and now it got a pair of homemade hinges for the door.

Any tips of where I can find a suitable 1:8 driverseat?

well done Driver´s Cab, Laban!

Please let us know, which cordless drill is the benefactor of the gear?

greets
Markus

You can find driverseats on the page from Ruediger Schink www.schink-1-8.de
btw nice cab that you build .

It's been a really long time since my last post but that doesen'n mean that nothing's happend. I fell for the idea to use the Robbe Roxxy 2827-34 motor for the track drive and use parts from Black & Decker EPC12 cordelss drills to build the gearboxes. The result is two three stage gearboxes with a reduction of 1:166 an additional 1:2.67 reduction is in the rollerchain driving the chainwheel and it sums up to a total reduction of 1:444.

I will be ready for the first testdrive of the undercarriage very soon

Now I have a box full of donors.
The gearboxes had to be placed side by side to fit.

nn

Ich fühle mich durch die nn Kommentar beleidigt. Keine Updates mehr gemacht werden.

Mann super TOP

Off Topic:
was bedeutet denn "nn" ? Warum muß man dann beleidigt sein ?


Ansonsten kann ich nur mein Lob für den Bagger aussprechen, ich wäre glücklich wenn ich so ein Prachtexemplar bauen könnte

Endlich fertig

That's a great piece of work!
We would love to see a video of it, doing some work in the dirt.

Congratulations for being loyal to your project for 20 years.
I also have a project since 2012, and will not give up until it's finished.

Though there were some posts during my active years here, I must admit I didn't notice this thread. Maybe because excavators are not my focus.
But the scale 1:8 is definitely the right one!

Thank you!

Estimated build time was around 4 years but it ended up in a few more
I really love the size of the 1:8 models but there are some drawbacks. They are heavy to handle and takes upp much space in storage.

There will be a video available soon.

It took a while but now on Youtube.

https://youtu.be/I9pVta7KyO0?feature=shared