This was the direction I was heading for R/Cing my U1 232.i.e. open one, close the other, with one servo. Simple, once you have defined the servo rod lengths and positions on servo driver arm. Originally I tried driving these from the tender with R/C car universal joints. OK when running in straight line, but needed a sliding rod and tube system to take up the variations on drive lengths when negotiating curves. i.e. over 3/4" between full left and full right. Especially the tight rads. So placed servo in cab on right hand side with short, stiff drive rods to underside of throttle/blower handles. Eventually fried the servo wiring, after 12 months, with an alcohol flashback. But servo was still ok. Worked well under static tests on the treadmill, but not tried it under a real load yet.
Our Japanese friend Mr. Tanaka?, told me he puts the servo's under the side valances. But this seems to need long control rods, bent a various angles to hook up to throttle etc. At this point they are too flexible, and wippy. Especially when opening up a closed throttle with a hot engine i.e. to overcome initial closed friction.
On my U1 1/4 turn of throttle represents full stop or very high speed, so running at 1/16 to 1/8 open is the controllable norm, even with 40% cut-off and 8 coaches.
One problem I have seen is the inability of the servo to actually have enough torque to fully close the throttle, and give the final fully closed tweek.
I have seen photographs of a U1 with 5 servo,s all driving from the tender. Seems to work, but does not look good. I do not like visible R/C Controls. Prefer them well hidden or disguised. Much more difficult when "adding on" to a ready built loco, without a major tear down. Especially a U1, Daylight or KGV ETC. Next time, I will add R/C as the kit is built.
Duchess has only two servo's controlling forward, reverse, cut-off, blower and cylinder blow downs for pressure release start up. Servo,s are buried between the frames. Also has hand throttle over-ride to pre-set for load. One servo does have not push rods, but uses rotating discs to open and close the steam ports. The 2nd has a bell crank for operating the Johnson bar.
Roundhouse and Rubies etc. no real problems, as controls are much more accessable, larger scale and open.
Regards,
Tony D.
At 11:49 AM 11/26/02 -0800, Geoff Spenceley wrote:
Barry Harper of Diamondhead fame R.Cs his alky locos--no problem. I forget how he controls the blower--but one servo could open the blower and close the regulator and vice versa.--this may be what he does. Those 1/32 cabs are small.Geoff. --Gary - chilling in Eugene, Oregon >http://www.angelfire.com/or/trainguy >http://community.webshots.com/user/raltzenthorWhy do so many say it is >impossible to R/C an alcohol fired loco? >My logic says if a servo is available for throttle, blower, and reversing >lever then the loco should be R/C controllable. What am I overlooking? >
