Posted January 25, 201114 yr Here is a excavator I found on youtube.In my opinion they are some issues with it,the pump works well Edited November 8, 20159 yr by Alasdair Ryan
January 25, 201114 yr RC pneumatics..! not bad! Althought I still think air pneumatics or not for excavators..
January 25, 201114 yr Alasdair, I am glad that you push your Excavators project further, and it looks good! Rotation of the superstructure is nice and smooth, so is the drive, but I don't like the pneumatics here at all. They are impossible to control properly and its movement here just look totally unrealistic, imo. They can be controlled better with manually operated switches. Pneumatics do rule, but not here, on this scale and on this type of machinery it is better to have LAs.
January 25, 201114 yr Again not as good or as good looking as 8043' pneumatics are just not suited to machinery at all and cylinders joined back to back looks really bad.
January 26, 201114 yr Author Alasdair, I am glad that you push your Excavators project further, and it looks good! Rotation of the superstructure is nice and smooth, so is the drive, but I don't like the pneumatics here at all. They are impossible to control properly and its movement here just look totally unrealistic, imo. They can be controlled better with manually operated switches. Pneumatics do rule, but not here, on this scale and on this type of machinery it is better to have LAs. i have started on a new excavator myself if any of you want to help you are most welcome! i am working on a excavator for a youtube guy (no la's or puematics)
January 26, 201114 yr Don't listen to those guys, pneumatics are perfect for this. They can't help it if they can't design a decent setup and are too ham fisted to operate them properly
January 26, 201114 yr Don't listen to those guys, pneumatics are perfect for this. They can't help it if they can't design a decent setup and are too ham fisted to operate them properly How do you know that pneumatics are perfect for this? Did you build similar size excavator as Alasdair did, both with pneumatics and LAs?
January 26, 201114 yr How do you know that pneumatics are perfect for this? Did you build similar size excavator as Alasdair did, both with pneumatics and LAs? Yes. My LA one (built 2009) improved on the 8043 in terms of performance, but still didn't match my pneumatic ones. Besides I don't see why people say pnaumatic excavators don't move realisticly. I've not seen an LA powered excavator (that doesn't have to run on 11.1 volts!) match the performance, realism, power and versatility of my pneumatic ones or many of the others seen on youtube, such as: This one even has a telescopic boom! and there are plenty more that move realisticly if you look. Anywho, lets not hijack this thread as well, this discussion is getting old now Edited January 26, 201114 yr by allanp
January 26, 201114 yr My LA one (built 2009) improved on the 8043 in terms of performance, but still didn't match my pneumatic ones. Can I see pictures of those excavators? Alasdair built the RC pneumatic machine. As you can see here, I was commenting that: They can be controlled better with manually operated switches. The links you provided are models with manually operated switches, not RC operated. Regarding power and realistic movement and look, take a look at this one: Pneumatics could lift the arm of this size? They can't, I tried it. This line is the one I think it is not appropriate: Don't listen to those guys, pneumatics are perfect for this. They can't help it if they can't design a decent setup and are too ham fisted to operate them properly I think that everybody on this forum can write their opinion. I know we all protect what we like, I like both pneumatics and LAs, and I think you should allow other opinions regarding Alasdair excavator, such as BrickDemon's, davidmull's and mine...
January 26, 201114 yr The combination of looks and functionality is great. I'm sure you invested a lot of time and even more Lego pieces in this! I'm wondering: Is there any way to make the arm move at a slower and hence more realistic speed? Thanks for sharing!
January 27, 201114 yr the real test would be to dig arround something without tipping it over.. like some lego characters.. and really move some sawdust fom one place to another over a certain distance.. those cut and past videos of excavators just digging arround in the nowhere still don't show they are better then LA powered excavators.. just that they have more power.. but also not in all cases.. but I really like that the pneumatics are remotely controlled in the excavator in this topic. that's really great! Edited January 27, 201114 yr by BrickDemon
January 27, 201114 yr Don't listen to those guys, pneumatics are perfect for this. They can't help it if they can't design a decent setup and are too ham fisted to operate them properly Everyone has an opinion but u really seem to be the only one that constantly runs down la,s,iv never seen someone as obsessed about pneumatics like this,as we have all said before we like both la,s and pneumatics,I'm really looking forward to seeing new ideas for 8110 coming out this year, la,s just suit machines much better because of there persision,u talk about pneumatics in every post nearly and that's ur own opinion,only thing I'll find use for my pneumatics is letting down my ramps on my trailer for my 8043,let's just hope we see a better system on 8110 that will bring pneumatics in par with la,s on functionality.
January 27, 201114 yr its my excavator !!!! and my youtube account some more details: more videos are coming Edited January 27, 201114 yr by benjiii712
January 27, 201114 yr @Brickdemon I would like to make some "digging" videos in the next days The combination of looks and functionality is great. I'm sure you invested a lot of time and even more Lego pieces in this! I'm wondering: Is there any way to make the arm move at a slower and hence more realistic speed? Thanks for sharing! I used auto valves from Dmac his Brickshelfgallery: //www.brickshelf.com/cgi-bin/gallery.cgi?m=dmac I am 14 and from germany Edited January 27, 201114 yr by benjiii712
January 27, 201114 yr I agree with AllanP too, there is quite a few people that prefer pneumatics. That excavator AllanP posted is nice (I would rather have that over the 8043), and I honestly believe LA's have their place but I can not help thinking the 8043 is hindered by LA's a bit for the following reasons: 1) It is not even making an attempt at modelling real life machinery. This is a real big point for me, movement comes second IMO. I will always try to model as close to real life machinery as possible. At the end of the day, I could buy toy RC excavators that moved far better if I wanted 2) The dual LA's come out of sync quite easily. Would never happen with pneumatics. 3) Is the accuracy provided by LA's ever needed for an excavator? (the answer is no) Some people seem biased against pneumatics, I read on a blog someone was putting the Unimog down because it has them, which I find hypocritical as the model is not even released yet! I have an 8043 built sitting by the side of me, I kind of like it IMO its not the best Technic set I have. @Milan: By the looks of the video, pneumatics could lift a properly designed arm of that size. For a start it would not have motors on it hence a lot less weight, and it looks as if he is only using LA's on the end of the arm. I can not see what lifts the first part of the boom (I presume its like the second part), but the second part is done with rack pieces. So I guess LA's could not lift the weight of the motors and boom either
January 27, 201114 yr 3) Is the accuracy provided by LA's ever needed for an excavator? (the answer is no) Personally I think the answer to this is yes, absolutely. The accuracy of the LA's highly improved the playability for me.
January 27, 201114 yr Personally I think the answer to this is yes, absolutely. The accuracy of the LA's highly improved the playability for me. I have never had any problem with dual LA's getting out of sinc. If the gear train does not slip that cannot happen UNLESS you allow the LA's to go full travel and actuate the internal clutch. Until Pnuematic cyclinder have a means of feed back they can only be either fully extended or fully retracted. Also under heavy load they close to quickly to be realistic. If they were hydraulic (oil or water) then they would stop at any desired position which is what LA's do. LAs can be set at any desired position between full extended or full retracted. Most aircraft use electrically operated linear actuators to control flaps etc so there is a precedence for their use. The purfusion of hoses on models with pnuematic cyclinders detracts from the overall appearence. This can be a problem with PF elements but usually the cables can be tucked away out of sight. ONLY plus point for pnuematic cycliders is their colour being yellow. LAs should be made in yellow also. Edited January 27, 201114 yr by Doug72
January 27, 201114 yr I have never had any problem with dual LA's getting out of sinc. If the gear train does not slip that cannot happen UNLESS you allow the LA's to go full travel and actuate the internal clutch. I think that is quite a problem to be honest, perhaps its better with a PF speed controller rather than the on off types supplied. There are a lot of potential systems to make pneumatics more controllable, many of which have been stated by AllanP elsewhere on this forum Until Pnuematic cyclinder have a means of feed back they can only be either fully extended or fully retracted. Also under heavy load they close to quickly to be realistic. If they were hydraulic (oil or water) then they would stop at any desired position which is what LA's do. LAs can be set at any desired position between full extended or full retracted. Most aircraft use electrically operated linear actuators to control flaps etc so there is a precedence for their use. The purfusion of hoses on models with pnuematic cyclinders detracts from the overall appearence. You can have a lot more control than just fully extended or retracted, with careful design and control you can stop a pneumatic with more precision than opened/closed (limiting the valves travel for instance is just one solution). The cylinder will stay in place until the pressure drops due to leakage - it does not instantly loose air. The 8043 is not an aircraft though (I would love to see a decent aircraft model mind ), and real life excavators use hyrdraulics and have hoses running up the booms instead of UJ's and prop shafts. Here is a real life small excavator, not an LA in sight and it has hoses http://img.diytrade.com/cdimg/903288/8879897/0/1246033512/1997_John_Deere_190E_Excavator.jpg I do not see the problem with hoses detracting from the overall appearance. It is closer to real life and a lot more pretty (in aesthetics and engineering prowess) than UJ's and prop shafts in my opinion! . At the end of the day I love technic models that model real life machinery (even if it is a crude rendition), and for that reason alone LA's in the 8043 just do nothing for me . I do think LA's are a good addition to the technic family mind , but I think their place is in robotics and aeroplanes Edited January 27, 201114 yr by richthelegodude
January 27, 201114 yr Can I see pictures of those excavators? They are no longer built, I only have one pneumatic one half built right now. My MOCs really don't stay together for long as I don't have a huge amount of pieces. Regarding power and realistic movement and look, take a look at this one:http://www.youtube.c...h?v=wHHvxCMmnhY Pneumatics could lift the arm of this size? They can't, I tried it. You would have more chance lifting an arm of that weight with pneumatics than LAs, the excavator in the video you posted does not use either pneumatics or LAs to lift the arm so i'm not sure what the point of posting it was This line is the one I think it is not appropriate:allanp, on 26 January 2011 - 10:00 PM, said: Don't listen to those guys, pneumatics are perfect for this. They can't help it if they can't design a decent setup and are too ham fisted to operate them properly I think that everybody on this forum can write their opinion. I know we all protect what we like, I like both pneumatics and LAs, and I think you should allow other opinions regarding Alasdair excavator, such as BrickDemon's, davidmull's and mine... Sorry if it caused offence, it was only meant as a light hearted bit of fun, besides i'm not sure if Alasdair would appreciate comments like... "but I don't like the pneumatics here at all. They are impossible to control properly and its movement here just look totally unrealistic, imo." Is what I said really any worse considering it was only meant as a bit of fun compared to you lableing his latest hard work as unrealistic? It may be only your opinion, which you are entitled too (it would be boring if we all had the same opinion), what I said was also nothing more than my own opinion. Everyone has an opinion but u really seem to be the only one that constantly runs down la,s,iv never seen someone as obsessed about pneumatics like this,as we have all said before we like both la,s and pneumatics,I'm really looking forward to seeing new ideas for 8110 coming out this year, la,s just suit machines much better because of there persision,u talk about pneumatics in every post nearly Sorry about that, I guess with everything else I usually agree and find that what I want to say has been said (unless someone is looking for ideas or help with a MOC) so there is little point in me saying it again. Pneumatics and LAs are really the only thing I disagree with a few people on, so I post mainly on that. I have said before that LAs are not bad, they have just been used in too many places where I thought would have been great for pneumatics, and have been made worse in many ways in my opinion for the use of LAs. But i'm sure LAs would be great in places like robotics. Richthelegodude, you are clearly a man of wisdom, have agreed with everything you have said here so far. OK, that's enough now, unless there is something positive or informative to add, can this thread move back onto the awesome MOC posted by Alasdair? I'm beginning to feel sorry for anyone who posts a pneumatic MOC due to somebody saying it's unrealistic cos it's pneumatic and should have used LAs and PF and blah blah blah (one thing that has only worsened my own LA bashing out of retaliation and being annoyed at that type of thing). Edited January 27, 201114 yr by allanp
January 27, 201114 yr Most aircraft use electrically operated linear actuators to control flaps etc so there is a precedence for their use. Yes and no. Many aircraft use ballscrew type linear actuators to drive the trailing edge flaps, but the drive unit that powers those actuators is actually usually hydraulic or pneumatic. Yes, you heard right, some current commercial aircraft use a pneumatic motor to drive the flap system. There is often an electric motor as a backup system. Virtually all aircraft flight control surfaces are driven by linear hydraulic actuators. Most leading edge slat systems and some trailing edge flap systems are driven by geared rotary actuators. Both the linear hydraulic actuators and the linear ballscrew type actuators are capable of moving to a commanded position and holding that position. A mechanical actuator would continue to hold that position over time with no power, while a hydraulic actuator would eventually bleed away the pressure and return to neutral without power (just like LEGO excavators). Construction equipment, so far as I am aware, always uses linear hydraulic actuators. So yes, there really are such things as electro-mechanical actuators in the world, and they really are used for some cool stuff, but they are not used for excavation equipment. I have never had any problem with dual LA's getting out of sinc. If the gear train does not slip that cannot happen UNLESS you allow the LA's to go full travel and actuate the internal clutch. If the system is properly designed, the 24 tooth clutch gear will slip before the internal clutch in the linear actuators triggers, so they should never get out of sync. I have not had my LA's get out sync beyond that which they have when originally assembled. As discussed in another thread though, they do get 1/4 turn out of sync as they go from boom-down to boom-up because the drive gears face opposite directions.
January 27, 201114 yr Thank's for Sharing MY video!!! Anyway, welcome to eurobricks, benjiii! Your creation is really sophisticated and functions quite well. Also it's one of the few Lego excavators that have a 2-section-boom. This is great work and the fact that you are only 14 years old makes it even more impressive! It's good to see someone from Germany here in the Technics forum Of course I know efferman but still we have imo a massive lack of technic moccers from Germany here at eurobricks. What's the reason for that? I really don't know. I'm looking forward to see more videos of your excavator grindinggears Edited November 8, 20159 yr by Alasdair Ryan
January 28, 201114 yr Guys, just to stay on topic, despite the differing funcionality of LAs and pneumatics..I can see many people mentioned that pneumatic works just like in a real excavator. Yes at certain point, pneumatic actuator works almost in the same principle..a forced compressed medium, resulting in linear force (movement). But the medium is completely different. Real excavators use hydraulic fluid, instead of air..hence the name 'hydraulic'-taken from hydro. Liquid is much more dense than air, which sees why real excavator can move a heavy or light loads with the same precision. Anyway, I can see HUGE possibility of Lego creating an actual hydraulic actuators, where the hydraulic pump is powered by PF motors. The size of the current LAs is almost the same as an offroad 1/8 RC Nitro Buggy shocks, although the body is made of sturdy aluminum. So in theory making a small 'hydro-tight' element is possible. The medium will be silicone oil, which will be safe for the seals. Just picture it as pneumatics with fluid instead of air.. We'll just have to see what Lego has in store for us in the future..
January 28, 201114 yr Anyway, welcome to eurobricks, benjiii! Your creation is really sophisticated and functions quite well. Also it's one of the few Lego excavators that have a 2-section-boom. This is great work and the fact that you are only 14 years old makes it even more impressive! It's good to see someone from Germany here in the Technics forum Of course I know efferman but still we have imo a massive lack of technic moccers from Germany here at eurobricks. What's the reason for that? I really don't know. I'm looking forward to see more videos of your excavator grindinggears Thank's and more Videos are Coming (for now http://www.youtube.com/user/Benjiii712) I am working at a tipper Truck no, but the Problem is that excavator allready use all chanels so i Gould like to Control it with the nxt and MY iPhone Sorry for MY Bad englisch @grindinggears,I come from NRW Edited November 8, 20159 yr by Alasdair Ryan
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