So I am on this learning curve right now to design the neck head movements of the Terminator project, Thirsty for knowledge on the regular or HDD servos and what is the difference between a servo Linear actuator and a regular servo? I am thinking that since the new Linear actuators seem to resemble what were used for a long time with RC car steering mechanisms and what my brother uses in Pneumatic air cylinder pistons to control fast moving Props for movies and stage shows. My bro was telling me to go with the Pneumo cylinders but I want the Bot to be able to move around the field at summer Festivals we have outside. Must be Electronic and mobile, with no Giant air compressor to haul around LOL! Does anyone know if these actuators are faster than regular servos with movement speeds? Also would the Linear servo handle more load as a piston push pull mechanism VS a motor or regular servo with a cable attachment? I am leaning on getting the Linear actuators to replace the fake chrome pistons that go on the Terminator head,neck,chest,back and the giant fake pistons that go at the hip Chest connection. The price of Linear actuators are expensive just like the more expensive high torque servos, so ya ..Decisions, decisions. https://www.robotshop.com/ca/en/linear-actuator-l16-100-63-12-p.html Now if I go check out the local hobby store here in town I can likely get much cheaper electronic servos used for Radio control vehicles like used for hobby Monster truck steering or Hobby R.C. airplanes.but not likely as large or powerful as these new ones from the robot store inventory. So I learn something new everyday, I had no idea that this existed,perfect for hands and finger movement!...https://www.robotshop.com/ca/en/dynalloy-flexinol-006-lt-actuator-wire.html Arnold had too much Flexinol wire in his jaw muscle,LOL! Sorry guys thought this was Hilarious!...https://www.youtube.com/watch?v=nnrIdXWtOP8

I considered going Pneumo for a short time with my B9's arms. There is plenty of power you can put into a small space with less power needs them regular servos. It was tempting to use this method.  However in the end, like you I didn't want to find space for a air tank and compressor. The thing that really killed it for me was the noise. You will hear the compressor pumping air into the tank and the hiss of the air escaping when the piston moves. Maybe your brother know how to overcome these problems.

Linear actuators are hitting the market. Again like you said they are costly. Seems the faster they move the higher the price. [/font][/size][/color][/font][/size][/color][/font][/size][/font][/font][/size][/color][size=3][font=OpenSans, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji"][size=3][font=OpenSans, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji"]

I ended up buying a real nice Linear actuator from Progressive Automation for another part of my B9 (the bubble lifter). I haven't installed it yet but am real excited to upgread using this. If you order directly from PA they can custom build to your specs for no extra cost. Just choose what you need from a drop down list.

https://www.progressiveautomations.com/tubular-high-speed-linear-actuator

https://www.ebay.com/p/12vdc-High-Speed-5-9-6in-Linear-Actuator-DC-Motor-Stroke-150mm-Force-50n-Ts-ly/704186829

After playing with the drop down menu on the Progressive Automation website I see the price does change just a little as the stroke gets longer. However only by a few dollars. You can get strokes from 1" to 24" with a force range from 11 -33 lbs. It looks like the speeds will drop as force needs goes up. Fastest I see is about 9" a second. Slowest is about 3" a second.

Great vids Dave! That is what I was looking for some examples of Linear servo in motion. 9" per second is actually really fast for what I may need but again I need to balance with the cost. That Progressive web site is something to look at,so much selection!

And these guys have already done what I am doing, some others too I saw one video from 2015 so I am not the first but only difference I will have the entire body replicated and moving with actuators and another thing most people do not have the best robot controller EZ B! https://www.youtube.com/watch?v=AV36d7EbNSQ

some of you guys may be building great large robots as well. A good secret on trying to make vinyl or plastic look just like real chrome. Do not use most of the Wal-Mart or Canadian Tire chrome paints,they do not really work. There is a very few that come close to chrome or more like a polished Aluminum if clear coated(The clear coats always kill the chrome shine effect for some chemical reaction or just the coating results in yellowed or dull appearance) There is a paint that works great called Spaz stix about 17 dollars for a small can but it really looks like Metal Chrome on any material and the secret is to really lay on a high Gloss black first and then sparingly add a thin top coat of the Chrome paint,Gently buff after for convincing Metal chrome shine. Then the company Alsa is great too but way more expensive,they do sell a regular aerosol can for $50.00 called Killer Chrome that looks so good,they use it in auto body shops to repair chrome bumper damage and they have a new one too that works better but too expensive called Easy-Chrome,100.00 for the minimum size,not worth it. Alsa also sells Chrome wraps that look so amazing you can wrap a car to look just like a chrome plated car! I have seen the Lamborgini's with this Black Chrome wrap that looks Jaw-dropping gorgeous. You can get these many colored wraps from Ebay and China way cheaper and easier to do yourself as they don't get damaged if you make a mistake and need to peel off the wrap. Just my 2 cents on Robot cosmetics,wraps can be used for anything as well....I am going to do this on parts of my Black Fiero GT like on the Big rear spoiler at the back as a Black chrome look,Hood with shiny Chrome area and the Pegasus Emblem,possibly the silver bottom side panels with Black Chrome. Also any future Robots of course, Cylon Centurian comes to mind!......update.....

After watching this youtuber, The Centurian just does not seem as menacing any more like what I remember as a kid, Possibly the Doctor Who Cyber-Man would be a cooler next build!.....https://www.youtube.com/watch?v=LVYGSg3Tujw

And this one just made me cringe,LOL!!....https://youtu.be/BkLQdX4lkAA

Glad that vid was helpful. It was actually done by a friend of mine down in Australia by the name of Steve Neal. He's built a B9 robot that rivals any other I've seen.

Dave that is awesome, a Small world indeed!