Tony D: Fantastic write up. Simply fantastic. I am amazed at how things are the same from full sized down to Gauge 1. Especially the delay or dwell time you talk about. Prior to heading into the curve on the smaller full sized engines we run, you have to give it some throttle or you die in the curve. The shay is the most instantly reactive, our 4-4-0T has the longest dwell. The diesels (25ton and 55 ton GE diesel electrics) are real dogs. Throttle must be provided before hitting the full impact of the curve or there is a noticeable slow down. I believe this is due in part to the time it takes for the relays to kick in as the generator RPMs come up. Very mushy, unless you really give the throttle a pull.
Great write up. Many thanks. J.R. ----- Original Message ----- From: Anthony Dixon <[EMAIL PROTECTED]> To: Multiple recipients of sslivesteam <[EMAIL PROTECTED]> Sent: Wednesday, April 02, 2003 3:34 PM Subject: Re: Materials compatibility > Hi JR, > Really good feedback, and I recognise many parrallel "actions and > reactions" in my 10mm scale coal burners. > I run two coal burners, one is controlled 'by hand", which has only two > controls, one for throttle and one for the blower, with a slip eccentric > controlling forward and reverse. Has a dummy Walschearts valve gear. > The second engine is radio controlled, with working Walschearts valve > gear, and R/C controls for the throttle, blower, Johnson Bar and cylinder > drain cocks. Also have an Aster U1 which also has full Walschearts valve > gear, hand controlled, and can be run on coal or alcohol. > With the slip eccentric engine, without radio control, after firing up > to 80PSI and with a red hot fire, I add 2-3 loads of coal before release. > The running technique is to use both wide throttle (1/2 turn open) > throttle, and 1/4 turn blower for starting off with 6-7 coaches, and once > under way, reduce throttle to 1/8 turn on throttle and 1/16 turn on the > blower. This gives a steady speed with enough throttle and blower, to pull > the load out of the tighter bends after natural slowing, but not allow an > "out of control" speed on the straights, heading for the curves. So almost > a set and release driving method. When the pressure drops to 30-35 lbs, > which is typically after 3-4 laps of my 300' track. I stop the engine, load > 2-3 loads of coal, open up the blower for approx. minute or so, build > pressure to 45-50psi, close blower to 1/16 turn and release again. I have > one really tight curve which brings the engine to almost a standstill, but > the blast increases greatly under this load, and pulls the load through > the curve and up to straight line speed again, till the next curve. > With the UI, a 4 cyl. compound with Walschearts and hand controlled. > The Johnson bar is set at full position, with throttle 1/2 turn open and > blower at 1/8 to start off. Once under way, and after approx 200', the > engine really takes off as all the cylinders warm up. So requires cutting > the Johnson bar to approx 40% cut-off, closing blower to < 1/32 turn and < > 1/8 throttle to achieve the same constant speed as above. However running > on alcohol does not give the really noisy blast when pulling out of the > curves. The U1 is a really quiet engine for its size. Engine will "cruise" > at 40-50psi for several laps before pressure drops as the alcohol runs out. > However the R/C Controlled coal burner with Walschearts is a totally > different animal. It has a "hand throttle" which can be pre-set according > to starting and running load, before release. This hand throttle remains > open at all times in pre-set position while running. The R/C control on the > Johnson bar, for forward, nuetral and reverse are infinately notchable on > the left hand control stick. The throttle and blower are controlled on the > right hand control stick, with the initial 1/4 of stick movement > controlling the blower, the next 2-3 notches control the cylinder drain > cocks, and remaining stick movement controls the throttle. Which is also > infinately notchable. At firing up, the hand throttle is closed, R/C > throttle closed, and R/C blower is opened when pressure reaches 45psi. > At 80-90psi at start-off, the Johnson bar is set in fully open > position, the throttle is opened through the blower position and cuts it > off. The drain cocks are opened through 2-3 notches, > to blow down steam and water and then throttle opened more to move off. As > the load is taken up, I reduce the Johnson bar by approx 10%, and back off > on the throttle. As speed is built up, I reduce the Johnson bar setting > again to approx 50%. Typical running with 7 coaches and 50lb load is 1/2 > throttle and 50% on Johnson bar. With the R/C notchable increments, it is > surprising what affect 1 or two notches to the throttle and/or the Johnson > bar makes, and the amount of balance one can achieve and maintain. Thereby > actually "driving" the track as opposed to set and release. Which is > something never experienced in the non-r/c engines. Also there is a "dwell" > time between action on the stick and re-action of the engine, which takes > some getting used to. (I have flown R/C planes and used to "instant on" > controls). Also by throttling back into the blower zone and and opening up > on the johnson bar, you can generate more draft and build up pressure back > up, if dropping off. However this is the sign that the fire needs > replenising, but you do get some warning or feedback from the engine that > this is neccessary. When re-coaling I can keep the blower > open by R/C or by keeping the hand throttle slightly open and R/C off. > Types of coal are an entirely different issue!. > Regards, > Tony D. >
