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Looking amazing Jonny!
It is very cool to see the shapes from the diecast model scaled up it makes me appreciate how detailed our toys were back in the day.

What felt like a bit of man 'flu staring the week before Christmas developed into an antibiotic resistant dental abscess in the New Year, by Saturday morning most of the elephant man level of swelling had gone down, today it still hurts like badword & I'm still running a high temperature - and although I'm still really not up to doing anything, I'm beginning to get a bit bored with TV, reading, and waiting for the next dose of pills ... so it's not that I've made progress with the build as such, just that I did make some (or at least take some photos & make some notes) a couple of weeks ago but failed to post it until now:


There wasn't much detailing to do on the top & back, but that's been done + I temporarily sorted the wiring & had a short test drive - which highlighted some snags to fix:

- steering has gone assymetric (steering much better one way than the other) again & centring really isn't work very well;

- ditto for the unloader boom, I can set it up right, but the next time I come to use it it's gone wrong again ... i suspect the pair of metal gear servos I bought for this were trash...

(replacements have arrived but are still sitting in the box);

- a couple of mm needs taking off the studing that makes up the reel shaft;

- the cab needs reinforcing (or something), especially on the right side where it's warping quite badly ... my fault for using thin sheet to save weight - as if it matters on a vehicle with an all up weight around 7.5kg ...

- the 12v fan is spinning so slowly on 6v it might as well not be there, I gave up waiting after 6 weeks for the 5v replacement from China so ordered another from Wales (they were out of stock initially) ... that took several days longer than expected & both arrived on the same day;

- still need to sort some method of battery fixing, it probably won't be a high tech solution - I'm thinking stop strips, hooks and elastic bands.

-amber beacon is very small & the blue anodised base is very wrong ...

I hope that you will be better fast Jonny.
Next week I go to hospital to remove 2 teeth. . Better health for you Jonny.

That is one amazing build

stingray-63 wrote:

I hope that you will be better fast Jonny.
Next week I go to hospital to remove 2 teeth. . Better health for you Jonny.

Thanks Stingray - and good luck with your extractions too

After rallying last weekend, I went downhill again until the early hours of Thursday morning when it finally popped after dozens of cups of tea (with honey & lemon) to draw it out... I don't think I'll ever be able to look at a Cadbury's Creme Egg again though The tooth was pulled Friday morning so it's hopefully over, bar the healing up.



Today I removed the problem servos - a pair labelled TowerPro MG945 - very disappointing as I'm sue I've used similar ones without issue, but on the bench these are noisy & wobble about during movement, and the end of a movement badword horribly. In use they don't centre reliably & are very difficult to set up.

The replacements are Turnigy TGY-AN13 & look almost identical aprt from the label and being marked "C E" (note the space) on the bottom, instead of "CE" & the "no dustbin" symbol. On the bench they are a lot quieter, don't wobble & badword, but are visibly slower ... fitted they seem to work better, but I haven't done a fully assmbled/loaded test.

The unloading boom has a lot of potential to undo fasteners through inertia if it hits the end points too hard, I've ordered a servo speed regulator to plug in & increase the transit time to a more scale looking speed, regardless of how fast I twist the TX knob - it really doesn;t need to snap to attention.

Thanks Jonny.

Hey guys,
Hope you are both feeling better after your dental ordeals .
The combine is looking great Jonny! To bad about your servo woes...I have had good luck myself with the Turnigy brand servos ( despite what the radio elitists say " well you know, I only use brand X because it is the best bla, bla, bla"....) so hopefully your troubles will be over. I am interested to know how that servo speed controller works out could be a useful bit of kit to know about for future builds.

This is one of the best custom builds I've seen Jonny, nicely done. I was looking over it last time you posted.

I'm sure I recall having similar servos or something years ago and an issue, maybe just a bad one but I think it was twitchy and would just spasm on its own accord.

Keep up the good work and hope you also make a fast recovery.

The servo regulator is a tiny thing, with 4 sets of pins - one for input, 3 for ouptut. 3 tiny potentiometers (on the the other side ) control servo direction, speed in one direction, and speed in the other... more features than I need TBH, but between it, a new servo, and adjusting the end points (100% in one direction, 60% in the other), the unloader boom is now set up as I'd like it, with a fair change that simply using it won't mess it up ...

The regulator seems to work by chopping the servo travel up into discrete chunks & introducing a delay between them - and that's problematic with the boom being so long (so any slack or irregularity is magnified at the far end), and heavy (by RC component standards)... at the "slow" end of the pots, travel is about 10 seconds, but is divided up in to move wobble wobble, move wobble wobble, and repeated over the whole half-meter travel. At the "fast" end, it's not slowed down at all (as expected), I settled on a transit time of 2.5 to 3 seconds, at that rate you can hear the servo going on and off, but the intertial swing forward at the end of the movement is just finishing as the next push fro the servo is coming, so it gives the illusion of smooth movement.

Units like this promise scale movement without the expense of buying "slow" servos for plane undercarriage & so on ... I'm not convinced they delivery, though it's working well enough here.





I finally got around to sorting the battery stay ... I've used heatshrink over the ends of the elastic bands & on to the brass hooks to make it a bit tidier/safer ...





The egine on the 1:1 version is a turbodiesel (driving hydraulic pumps for motive power etc) ... it's a sound that doens't seem to be replicated by any sound unit at present - some IC negine noise but mostly a lot of air getting compressed. I had hoped th fan would go some way to at least hinting at that, but no. I looked briefly at ducted fan/motor combos (along with a cheap brushless ESC and an servo tester for speed control input/note tuning), but they're always going to some more like a jet turbine.

Plan C was to upgrade the fan motor, so I machined up a boss/adaptor to take a 540 motor ... the fan certainly shifts a lot more air, but initial testing suggests the resonance set up in the body is at far too high a frequency. My initiall thought was to reduce the voltage by means of resistors, but burning it off as heat (a la old Tamiya MSCs) seemes wasteful - I will try a leftover ESC & servo tester so see if I can get a better pitched sound before going to the hassle of making motor clamps ...

Jonny wrote:

... I will try a leftover ESC & servo tester so see if I can get a better pitched sound before going to the hassle of making motor clamps ...

Hmmm ... noise reduced from really loud & annoying to more tolerable (but with much less air) ... just sound like pointless motor vibration though, so really not worth the extra work & complexity.

I guess that means it's time to dismantle for paint, trying to do something about the warped cab side on the way.