MangaNOID

I'd love to learn how your doing this as I would like to build a car chassis one day. To me it looked like the cylinders would pop off where the top two red 2L axles (verticle ones) are holding them on, when suspensions is loaded.

I looked at this and didn’t think the small cylinders would take the weight of a car so I just tried one pumped up and one cylinder can take a kilo of force quite well, so no doubt this MOC will not weigh more than 4 kilo the feel of the cylinder squishing was a nice feel too. It will work really well for suspension I do like a MOC with pneumatics. will the front cylinders pop off their top support though under load?

Haha! If only we all had the willpower to do that. Your whole post is one of reverse psychology inspiration for sure I know this won’t be the best build but if it works without falling apart and has the functions I originally wanted (operated from the cabin) then I’ll call it a success. I am being positive today (after last night-see below) as the only flaw I see in it is the slight flex in the tracks in relation to the undercarriage chassis. I’ll make sure to show this in the video for anyone interested. Once again @@jotta93, Thankyou for poking me in the ‘continue’ direction. There are so many times I have been disappointed and just wanted to do something more simple with this but I do find it hard to give up ideas (even if the end result is a little compromised) there will be a video on this for sure even if it does end up highlighting the inadequacies of this build But, I did have a good 45minutes last night to test some thoughts and test the operations again and it was looking rather good after a couple changes! So I’m Mr happy today. I didn’t think they would fit so I never put them on but after trying last night the little round wheel things for the tracks do indeed fit and make the drive much smoother! I can have 3 each side. I also reverted to a previous setup (I’ll spare the boring details) that allowed the tracks expanding pump to be almost twice as fast. So much better. So a couple items scrubbed off the list from above. I’ll try not to overwhelm the airwaves here. I’ll wait for my bricklink order. Fix another two items from the above list, Shoot a video and come back with it all done soon I hope.

This is quite nice indeed in such small scale. Two things I may not be happy with though (not that I could make it any better) is the turning circle looks not great from the video? also could the gears be changed to speed up the tipper bed? then it could be a really great MOC... IMO

Hold your excitement @jotta93, that only leads to disappointment! -This thing is getting heavy and almost too heavy for the two M motors to move it. -The track expanding pump spins so slowly that it takes a whole minute for the tracks to expand or retract. -There is gear slipping when slewing left. -The drop down mechanism to drive the lower chassis functions has to be very aligned for it to drop into the lower chassis drive thingy’s. Slewing to those points is a bit frustrating. -The blade moves faster going up than it does going down. -The tracks are a little flexible as said before, as they are only secured on by two pneumatic cylinders each side. -The drive wheel in each track rest on the ground (instead of usually lifted up a little) so the drive movement is very bumpy as the wheel ‘climbs’ over each track segment, -maybe some other stuff... I can fix maybe one or two of those things above but to fix all of them I do have to get rid of the expanding tracks. They are the trouble maker in this build. I will finish the model with them and post a video but after that I will no doubt build a model without the expanding tracks which will be way lighter, more playable, more structurally robust and just better all round I think. too much stuff going on maybe ruins a good model. call me Mr Fickle with this build.

thanks @I_Igor seeing others builds sure does get your own ideas flowing. speaking of which I had some inspiration from this build below. it was the only mini excavator that I found on the net and wanted to proportion mine similarly. which is also why mine will not be yellow of course. I rather like the red and white of the Japanese Takeuchi brand. anyway I hope that colour will be the only thing to procrastinate on with this model if it all comes together.

I also say this should be pinned. a great explanation of lots of info. I found axles frustratingly very hard to build for steered sprung driven that actually work well with proper vehicle characteristics, so this should help guide indeed

6 steps forward 5 steps back so I haven't updated much as I'm just tweaking what I have really. I wont list all the tweaks there is too many. highlights though so far are that I am less negative abut this build after realising that 5 of my 7 small 1x6 pumps don't work very well. i do not know why but i will try to clean them? they work an unloaded cylinder but will not work on this model which was obviously annoying until I realised this. so now using the 2 good ones I have the model can indeed lift itself up using the main and secondary arm (and the blade of course). it takes a little time but none the less, it makes me happy. this now still leaves room for a LEGO battery box which I am happy about indeed! testing all the functions now seems positive so I am now doing open undercarriage surgery to place all the pneumatic hoses for the tracks expanding. it is VERY tight for space so I have to have no slop in the hoses and be as neat as I can. I only had some yellow leftovers to use as hose which looks awful but it shouldn't be seen in the end at least. after testing this it really should (hopefully) be just a small bricklink order for some parts for the seat and other cosmetics and a couple more threaded axles.

I think it may be hard to gain interest in competitions that are not TC or official Eurobricks contests as the last two challenges, the AMS_1 and 2 (started by @letsbuild) on the technic forum that I remember (and entered) (beside the buwizz comps that have great prizes) have been unfinished after all the effort that went in from contestants. not that that's the be all and end all of course but its a bit 'WTF' you know.

Hey @Kio Liex thanks for your comments! I hope the end results will be impressive...we shall see good suggestion about the star wars figures and i wanted one for the model photo shoot in the last pages but I do not think i'll be adding a driver. maybe for some still photos but the extra weight may make this a failure Good suggestion @I_Igor and I actually do have a small 'brace' thing on the front and back of the turntable. it helps a little but I think in the above photo the flex might be exaggerated do to the flex in the blade support...hard to explain but I have re designed a new blade support that may be stronger (yet to build it) we shall see. no matter what though I will not eliminate the flexing. I did try another support much further back but the weight going through it pulled some of the upper chassis loose! I may just need some more of those threaded axles. below is a look at the new blade setup. hard to see probably but anyway, the green axle is where the threaded axle will be. the pink thing floating is the drop down drive that mates to a turny thing below to drive the small blue pump for the track extenders. there is of course as mentioned another turny thing the other side of the lower chassis that drives the blade LA's up and down

Thanks for the enthusiasm Jotta93! I hope you get some hobby time soon! I get about 5 hours a week at the moment. plus some thinking a doodling time at work of course So, I’m getting a bit hesitant about whether the expanding tracks (especially in this non manual form) is worth it or not. It is compromising the structural integrity of the undercarriage. Mostly when doing the ‘excavator trick’ below though, so I will continue, everything is working…Just! but this certainly would not make an official set with this setup. I’ll hopefully explain as I update. One of the main things I wanted this excavator to do is be able to lift itself off the ground, to then be able to expand its tracks. Just like the real ones can do. I do not think this is entirely necessary on a real one (or this one on a smooth surface) but is a neat trick. I just finished with the front blade (almost. it needs a little cosmetic tidying). It is ‘upside down’ compared to most setups as the drive axle comes through the very bottom of the chassis from the rear, so had to put the LA’s at the bottom. But this blade is driven from the upper body and can, so far, lift the excavator. After that you have to slew the upper body around 180 degrees (it only just manages to do this…just, because of the slope angle of the body) and use the digger arm to push into the ground to lift the whole thing up on only the bucket and the blade. Unfortunately the small pumps are nowhere near strong enough to do this on their own so I have to switch (pneumatic switch) the main arm cylinder over to a large manual hand pump to pull this trick off. There is still a little more weight to go on the model such as small battery, roof and operator seat but hopefully it will all still work then In this pic below you can hopefully and rather unfortunately, see the weight pressure on the turntable with the undercarriage quite angled compared to the upper body. only one side of the upper and lower parts take the weight which causes this squeeze So I also admit I have to get some threaded axles to keep the blade held in to the chassis at this stage as any wobble or sudden movement can, at the moment, pull the LA’s out and everything collapses. I have one from my 8851 set but need another on my next brick order.

that make sense the way you say it for sure. In fact you gave me an idea of how I may be able to speed it up (just the pumps) a little more. I'll see if it helps any. another thing i forgot to mention is that i had to take apart the cylinders to get them working smoothly. Even though they were not used much at all from 42053. I added some vaseline to the bore and seal which worked a treat. instead of taking 40-50 pumps of the small 1x6L pump it only needed 15-20 to extend a large cylinder. much more efficient.

small but significant update is that I have finally sorted out the pneumatic setup for the upper chassis. This proved very frustrating to me. I have settled with 2x 6L pumps driven by one XL motor, which also drives the slewing and lower chassis stuff like dozer blade and tracks expansion (if they work as I haven't made that circuit yet) one pump drives the main boom the other pump drives all other pneumatic functions. I started off with an M motor for all of this but when pressure built up in the lines when the pneumatics were not being used the motor slowed and stalled untill the pressure released by using the functions. that meant no slewing could be done either so I had to go back to the XL motor, but that was a lot slower than the M motor in RPM so I used a chain drive to speed the pumps up a little. It works quite well but all a bit in slow motion. maybe that's normal for Lego pneumatics though. I tried double pumps on the one circuit but I just could not make that work under load I have done away with the air-tank too as that hinders rather than helps in this setup for some reason. I guess the small pump takes a long time to fill the tank, to then send that pressure to the cylinders rather than straight to the cylinders. I re worked the rear section many times to get this setup below that seems rigid with the chassis and good enough for splitting one motor into high speed pumping and very low speed (~5rpm) slewing without the air-tank I should also be able to put the battery box 8x4x5 (even though I wont be using it I did want to make it pure Lego build in theory. big relief to get this part sorted so i can work on the undercarriage blade and single pump now. the controls are very nice to use, very intuitive, just like the real compact excavators!

Thanks! I hope this is on track too! This feels better solution when using the tracks for sure, really solid feeling and can stall the motors without clicking if I put my hand in its way, but still a little disappointed with this solutions lack of Technic’ness. Thanks! I’m building an LDD file as I build and would like to make instructions for this even if it’s just for me to re build one day (if it all works in the end that is) but I realise how difficult instructions are and what with pneumatic tubes going everywhere it could be well beyond my abilities. We shall see. And I can’t post without a picture so here is how the tracks sticks work to the polarity switch. Its not a solidly connected connection but it works a treat. Although the feel of the switches is not as nice as the gears and clutch parts from before that click in place. Also (because we all like pictures but with fear of over saturation) there will be a couple of built versions of this (in the digital world anyway) one version will be built with the Lego rechargeable battery box as the seat base and the pneumatic tank outside the body behind the driver seat. The build I will do in real bricks will have ‘loose’ single 9V or Li-po battery under the seat with the pneumatic air tank hidden under the seat also to keep the outside look a little cleaner. Each version is easily changeable to the other with no real chassis modifications needing to be made.

Yea, certainly not intended as an insult but white connectors remind me of bones of course, and your MOC is certainly the most amount I have seen together ever and that ossuary is the most bones I’ve seen together. Red chassis black car…not my cup of tea. Neutral colours chassis only for my eyes really, but that’s mostly because I’m boring

Sorry, im posting an update as it keeps me motivated. the transplant of the m motors and polarity switches has been quite successful. Although they are very visible in the current position. I had to move them from being directly under the tracks levers as the throw on them is too much with the long levers, so I put them off to the side with a liftarm setup connector to decrease the throw by about half. reverse sticks... Forward sticks... The tracks drive really well now. No clicking through the coaxial etc. I hAve a worm gear setup with 8T for final drive to each track though. I connected the arm pneumatics and all is working well! I am hoping one small pump feeding an air tank will be enough for continuous ‘play’.

love it. it has a great style of dorky futuristicnes too it. I mean that in a good way. and functions, so many of them, great fun for the target audience.

Great MOC, as others have said that chassis pic is sweet! And that suspension, oh man I wouldn’t know where to start And at first look it reminded me of that bone ossuary just outside Prague, which looks like a whole bunch of white connectors at first glance when entering

3: 10 5: 6 4: 4 8: 3 17: 2 13: 1

I got flicked in the eye with a rubber band once, so not much of a safety device there great model, great functions! so much happening in this.

thanks @steph77 I do have those laying around unused () I have had a look through the free (? ) building instructions and I think I can get most of the way through the Technic bits no problem actually but Im probably just missing a few half liftarms L shape and turbine elements so I'll give it a go in the next few weeks when there is time and see how far I get and add any to future bricklink orders as necessary. again.

this is such a great truck! its so small that the finer lego elements look quite large. well done indeed! I wouldn't add any pneumatics to the LA arm as that would be weird to have both on there... but you could possibly improve the arm playability by using pneumatics instead...

Love to see this finished so hope the bits arrive and or the close of tc-15 can be held a little longer cause so far it looks incredible!

So in essence this all makes the AH-77S more manouverable... yeah I don’t understand but interesting nonetheless. I’d like to build this thing to see what one of your helicopters is all about. Thank you for making instructions @Ivan_M I’ve got many parts missing from the list though but all in good time.

Superb build! do the blades on the real one really tilt like that? Incredible! I’ve never seen like that before. I’m no guru of course though.