Thanks for the responses!
Cossett, I joined this forum as a result ot the invite you posted at...was it the truck stop or commercial? Anyway thanks for the link!
As far as my skills go, I think it's been more an issue of determination. I don't like soldering, for one thing. I learned what I know about machining on this project, and that has been a blast so far. With a ton of trial and error, this thing has changed so many times i could almost assemble all the original pieces into it's former self! Plus, it started out as a stationary carrier with a cable tethered power pack for the upper, that all went bye-bye, and the learning curve started all over. RC had some hidden challenges.
Styrene is my comfort zone, but I usually give this project the summer off, and this is it's 3rd or 4th. So the body work is waiting, and I'm thinking about designs on that. Lotsa ways it could go.
1/24- 1/25 is my scale of choice for everything other than HO. You'll probably notice that the crane is usually perched on an unfinished HO model railroad. Anyway, the crane will have it's own fleet of tractor trailers in the same paint scheme. Building it in 1/25 has proven harder than I thought, space is at an extreme premium in both the carrier and the upper unit. There is even a battery in the carrier's fuel tank to help save space. The frame is loaded with either mechanisms (more on that soon), or batteries. There is room in the upper unit for one more drum (winch) but it would require another channel. I may use another 2 channel radio to operate it later on.
The crane is freelanced, but follows closely real crane designs, fairly on the modern side. I couldn't find complete enough drawings or a prototype that sits still long enough to pattern after, and I got tired of looking and waiting, or finding one that could be mechanized using the available motors and such.
One of the mechanisms in the carrier's frame is this lifting unit that lifts the stack of counterweights onto or off of the upper unit's deck.
A real crane stacks it's counterweights on the deck with either a short boom, or a special setup boom. Then when it has them stacked on, it rotates 180, and hydraulics in the carrier lowers the set onto some kind of hooks or platform on the upper. This was a pain, but when I saw a real crane do this, I HAD to have it on mine!
The idea is that the little "cart" rides in a set of ramps. The card is held in it's relative position on the frame by a tie rod. The ramps push or pull under it, raising or lowering it as need be. The ramps are driven to and fro by a long threaded rod with a motor-gearhead. (that 3rd channel on the radio is a shift control) This doesn't have or need speed control, just a servo that kicks a DPDT switch, and then limiting switches at either end of the throw with diode bypasses for change of direction (polarity). It works like a champ, has no trouble lifting the 8 lbs of counterweights.
Counterweights here are on the carriers lift unit. I have machined out more clearance room since thia picture was taken off the underside of the deck
Weights now on the upper unit. It look like a gap between the deck and weights, but there were spacers in there. That has been improved a bit too. Operational for about 2 years or so, I still get a kick out of watching this whole process work!
As on a real crane, the gantry can not fold down with the weights in place for transport, but the crane can move around, and can even carry a load as long as the carrier and upper are in alignment, with the counterweights facing forward, the load behind.
I mentioned motors earlier. I have some sources I can link you to if anyone is interested in these gearhead motors for other mechanized purposes. I could very easily see an operating 1/16 wrecker unit using these guys. (I'm not gonna get into another scale myself...huh-uh)
Still more later if anyone is following...Dan