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Model Forum / General / Railroads / May 2008Not model RRing, but impressive modeling
Video of very nice, and very skillfully controlled, B-29 and X-1 models. The B-29 is powered by 4 chainsaw engines. But it would seem to be unprototypically over-powered - how many B-29's could do Immlemann's and outside loops? Geezer http://users.skynet.be/fa926657/files/B29.wmv > Video of very nice, and very skillfully controlled, B-29 and X-1 models. > The B-29 is powered by 4 chainsaw engines. But it would seem to be > unprototypically over-powered - how many B-29's could do Immlemann's and > outside loops? Geezer The models *have* to be overpowered. After all, where is anyone going to find the scale-length concrete-paved runway that would be required to get an accurately power-loaded model B-29 off of the runway? (The WW2 Tinian runway was 6,000 feet in length. If the model were built to 1/8th scale for instance -yielding a 17.6 foot wingspan- the scale runway would have to be 750 feet long...) And there's another aerodynamic problem as well: it's known as "scale effect", and it means that a model-sized wing is considerably less efficient that it's full-sized big brother. So you have to drag it through the air at a proportionally higher speed to get the same amount of lift that the larger wing would get at much lower airspeeds. Taken together, these factors mean that even if you had an accurately power-loaded model of practically *any* aircraft, and a scale length runway to fly it from, there's a very good chance that it would never be able to get off of the ground under it's own power! > Video of very nice, and very skillfully controlled, B-29 and X-1 models. > The B-29 is powered by 4 chainsaw engines. But it would seem to be > unprototypically over-powered - how many B-29's could do Immlemann's and > outside loops? Geezer > > http://users.skynet.be/fa926657/files/B29.wmv All modelling suffers from either a power or speed imbalance to the prototype. It's not entirely uncommon for model trains to exhibit these symptoms as well. Voltage and gearing frequently make them start, travel and stop much faster than their prototypes. Cheers, John > All modelling suffers from either a power or speed imbalance to > the [quoted text clipped - 4 lines] > Cheers, > John Not to mention the pure lack of mass compared to the prototype. There's just not enough mass behind a model engine (in railroading scales) to push the locomotive like what happens on the prototype. Sometimes you see the effect in G gauge, but rarely in HO. Puckdropper  SignatureYou can only do so much with caulk, cardboard, and duct tape. To email me directly, send a message to puckdropper (at) fastmail.fm > > Video of very nice, and very skillfully controlled, B-29 and X-1 models. > > The B-29 is powered by 4 chainsaw engines. But it would seem to be [quoted text clipped - 10 lines] > Cheers, > John Those problems can be got around in model railways by fitting sensible gearing and weighting as generally rigid structures hold our models against the force of gravity - model aircraft don't have that advantage. Regards, Greg.P. >> > Video of very nice, and very skillfully controlled, B-29 and X-1 >> > models. [quoted text clipped - 19 lines] > Regards, > Greg.P. They do, but scaling power and weight IAW the weights and measure of the prototype can be difficult. In 1959, Canada scrapped its only supersonic plane. In the mid 90's, CBC produced a movie about the plane which included some footage of the real plane and its 1/10 scale model which represented the flying prototype. You can tell discern the model from the actual plane because of its movements. On a sidenote, the modellers discovered that the more power they put to it, the faster it wanted to go. This was similar to the prototype as its limiting factor was skin temperature. But, they never got the chance to find out. If gearing and weights on HO were accurate, then 5 mph through a yard could be realistically modelled. But, who wants to wait that long? Cheers, John > If gearing and weights on HO were accurate, then 5 mph through a yard > could be realistically modelled. But, who wants to wait that long? Me. And, I'm given to understand, a rather large number of others as well. -Pete >> If gearing and weights on HO were accurate, then 5 mph through a yard >> could be realistically modelled. But, who wants to wait that long? > > Me. > > And, I'm given to understand, a rather large number of others as well. Sorry, but I'm not buying the "large" numbers of others. There's just too many "roundy-rounders" vs. those who merely operate their trains, let alone those that would move at 100% realistic speeds at all times. Let me put it this way: at my 60+ member club, I think there's maybe 1 or 2 guys that I have seen try to operate realistically while switching. The rest stop too abruptly (sometimes for magnets), accelerate too quickly, or couple up to a cut of cars that should be 10x the weight of the switcher and yet there is hardly a pause as all the cars instantly accelerate to the switcher's speed (one of these days, someone will invent -BEMF for decoders). It's not like they are zooming around the a layout at 200mph, but they are taking "shortcuts" to realism. Paul A. Cutler III ************* Weather Or No Go New Haven ************* >>> If gearing and weights on HO were accurate, then 5 mph through a yard >>> could be realistically modelled. But, who wants to wait that long? [quoted text clipped - 18 lines] > Weather Or No Go New Haven > ************* Since an HO model has 1/87^3 the volume of a full-size car, its mass should be in the same proportion. That makes a 200,000lb loaded car about 4.9oz in HO, and an MT of 100,000lb about 2.5oz. The NMRA recommended weight for 40ft car is 3.8oz. The NMRA recommended weight depends on car length, not prototype weight, and was arrived at after lengthy testing (in the 1950s IIRC.) It may be time to update the RP in light of better trucks, but it still won't change the fact that momentum does not scale at all well, neither does rolling friction, both of which determine how far the car will roll without braking. A full size car travelling at 5mph might roll 100yards or more on the level - there is no way other than a motor inside th car to mimic this behaviour in an HO model. If you think that scaling the mass to 1/87th in hopes of getting corresponding momentum, well, 1/87th of 200,000 lbs is 2,299lbs... ;-) HTH Signaturewolf k. momentum > does not scale at all well, neither does rolling friction, both of which > determine how far the car will roll without braking. A full size car > travelling at 5mph might roll 100yards or more on the level - there is > no way other than a motor inside th car to mimic this behaviour in an HO > model. > > wolf k.- I lived in Roseville, CA for several years, and enjoyed watching flat- switching in Roseville yard. The cars would coast majestically forever, even at almost imperceptible speeds, the empties coupling with huge echoing crashes. This fascinating action all seemed to happen in super-slow motion. With absolutely frictionless bearings and cars cast from depleted uranium we might be able to replicate that, at least in F-scale. > A full size car travelling at 5mph might roll 100yards or more on the > level - there is no way other than a motor inside th car to mimic this > behaviour in an HO model. I seem to recall an article in RMC or MR some 40 years ago that involved a rubber band around an axle drum, passing through a hole in the boxcar floor to turn the axle of a substantial brass freewheel. A few of those in the cut, and jackrabbit starts and stops might be reduced. SignatureSteve > >> � �If gearing and weights on HO were accurate, then 5 mph through a yard > >> could be realistically modelled. �But, who wants to wait that long? [quoted text clipped - 19 lines] > Weather Or No Go New Haven > ************* Do the old John Allen " ball bearings and buzzer" in a box car idea and have the club vote to approve a .25 or $1.00 fine for anytime an operator buzzes the buzzer during an operating session. It's a great way to pay for the Christmas party AND make operators learn to operate more correctly. You know what? >Do the old John Allen " ball bearings and buzzer" in a box car idea >and have the club vote to approve a .25 or $1.00 fine for anytime an >operator buzzes the buzzer during an operating session. It's a great >way to pay for the Christmas party AND make operators learn to operate >more correctly. This reminds me of the Top Post/Bottom Post argument. It drains the fun from any discussion when the train police show up. -- Ray > It drains the fun from any discussion when the train police show up. Sure, but you learn to expect that attitude from some people. I see the same exact situation in the music profession almost every week: "Drummers aren't *really* musicians.", "You can't play the Blues on a banjo!", yadda-yadda-yadda...........and in most cases the best thing to do is just smile, say something non-committal, and go your own way. But when there are a majority of them in charge at your club or whatever, and they begin leveling fines on anyone who doesn't operate the way they think you should, it's time to politely leave and either form your own club or build that railroad you've been planning all these years. -Pete > "Drummers aren't *really* musicians.", "You can't play the Blues on a > banjo!", yadda-yadda-yadda........... Ya mena, like "What's the difference betweena drummer and a large pizza? THe pizza can feed a family of four." or "A gentleman is someone who knows how to play the banjo - and doesn't." bada bing SignatureSteve > Ya mean, like "What's the difference between a drummer and a large pizza? > The pizza can feed a family of four." [quoted text clipped - 4 lines] > > bada bing Nope, but you score extra points for knowing a couple of generic musician jokes. What I'm speaking of are the guys who really and truly think that Ged appointed them personally to police the way other guys run their trains, play music, or any other occupation you can name. And who are more than willing to get in your face and tell you all about it. For instance: I recall an occasion on this newsgroup a few months ago when I posted asking if anyone knew where some old Walthers folded-paper passenger-car diaphragms could still be found, and one sanctimonious soul began his reply with "REAL modelers use such-and-such diaphragms"... ...There's a wonderful old-time musician named Doc Watson who was once being interviewed by a somewhat arrogant young writer, who began her interview by asking, "Doc, you don't really play Bluegrass or Blues music, so what do you call the stuff you play?" And Doc, who was quietly simmering at that point, replied "I don't know what you call it. But it's my guitar, and I play whatever the hell I want to play on it". Good for Doc. -Pete >> Ya mean, like "What's the difference between a drummer and a large pizza? >> The pizza can feed a family of four." [quoted text clipped - 12 lines] > play music, or any other occupation you can name. And who are more than > willing to get in your face and tell you all about it. [...] The really dangerous ones are the folk who decide that they have the Truth about politics and religion. 'Cuz G-O-D told them so. Signaturewolf k. >> What I'm speaking of are the guys who really and truly think that Ged >> appointed them personally to police the way other guys run their trains, [quoted text clipped - 3 lines] > The really dangerous ones are the folk who decide that they have the Truth > about politics and religion. 'Cuz G-O-D told them so. It's the same pathology in either case; it just manifests itself in differing ways. I've met model railroading rivet-counters who are just as dogmatic in their beliefs as, say, Pat Robertson is in his. So far as I'm concerned, both sorts are welcome to their ideologies, but are not welcome to try forcing me to behave according to *their* lights. -Pete <snip> > But when there are a majority of them in charge at your club or whatever, > and they begin leveling fines on anyone who doesn't operate the way they > think you should, it's time to politely leave and either form your own > club or build that railroad you've been planning all these years. Fines are a bit "over the top" in my eyes (we use peer pressure and a written critique in our club's newsletter for "corrective" action). However, I can sympathize with the thought. Those who run their trains like rocket sleds should not be in a club in the first place...unless they can find a club full of rocket sled engineers. Paul A. Cutler III ************* Weather Or No Go New Haven ************* > There's just > too many "roundy-rounders" vs. those who merely operate their trains, let [quoted text clipped - 7 lines] > decoders). It's not like they are zooming around the a layout at 200mph, > but they are taking "shortcuts" to realism. This comes back to the dream which i have had for a long time for DCC - I want to see a throttle with the control features of the old TAT-IV throttle. IOW, not just basic acceleration and deceleration momentum effects, but both a throttle and a brake handle, with release, service, lap, quick service and emergency positions on the brake. You can shut off the throttle but your train would continue to coast, only decreasing in speed very slowly like the prototype until brakes are applied. Like in TrainSim. Let's get some realism in trying to bring your train to a stop at the right spot, with over or undershooting the station or siding. SignatureRick Jones Remove the Extra Dot to e-mail me The Lake Erie & Oregon Railroad http://www.geocities.com/seventysixinchesoffun/ I love being married. It's so great to find that one special person you want to annoy for the rest of your life. >> There's just too many "roundy-rounders" vs. those who merely operate >> their trains, let alone those that would move at 100% realistic speeds [quoted text clipped - 18 lines] > Let's get some realism in trying to bring your train to a stop at the > right spot, with over or undershooting the station or siding. This may get someone "Off the Dime" so to speak. Because doing this would a fairly 'trivial' thing 'electronically speaking'. Chuck D. >> This comes back to the dream which i have had for a long time for >> DCC - I want to see a throttle with the control features of the old [quoted text clipped - 9 lines] > This may get someone "Off the Dime" so to speak. Because doing this > would a fairly 'trivial' thing 'electronically speaking'. The addition of a multi-position brake handle shouldn't be excessively complicated. The rest is just firmware programming in the throttle or base station, not in the decoder. SignatureRick Jones Remove the Extra Dot to e-mail me The Lake Erie & Oregon Railroad http://www.geocities.com/seventysixinchesoffun/ Necrophilia - the uncontrollable urge to have a cold one. > This comes back to the dream which i have had for a long time for DCC - > I want to see a throttle with the control features of the old TAT-IV [quoted text clipped - 6 lines] > Let's get some realism in trying to bring your train to a stop at the > right spot, with over or undershooting the station or siding. Um, this is already out there with QSI sound decoders. If you set your deceleration momentum (CV04) to a high level, the loco will "coast" for a long, long time. To stop the train, you must first reduce the throttle to zero and wait until the diesel/steam sounds goes into idle. Then you press and release F7, and one will hear an air release sound (which is supposed to be from the brake stand in the cab). The train "brakes" come on, and the train will slow at an increasing rate unless you "lap" the brake by pressing and releasing F7 again (the air release sound stops, but the train will continue to slow at that rate and no faster). One can accelerate and cancel out the brakes by merely moving the throttle above zero percent, or the train will come to a halt...eventually. Or, one can hit the emergency brake on the throttle and stop ASAP (w/ flywheels only). I've done this many times with my Atlas Trainmaster. I also status edit the address for 14 speed steps, while also boosting the starting momentum (CV03). This can get interesting, as you can use the push buttons on the throttle to go in 7% jumps, which is kinda like the notches on a real loco. The momentum smoothes out the speed steps, and the brakes do the same. It's a bit of a challenge, but fun at the same time. Paul A. Cutler III ************* Weather Or No Go New Haven ************* >> This comes back to the dream which i have had for a long time for DCC - >> I want to see a throttle with the control features of the old TAT-IV [quoted text clipped - 19 lines] > train will come to a halt...eventually. Or, one can hit the emergency brake > on the throttle and stop ASAP (w/ flywheels only). This sounds like a small step in the right direction, but still not as authentic as what could be done. Let's hope someone continues to evolve the idea into something more in line with the TAT-IV capabilities. SignatureRick Jones Remove the Extra Dot to e-mail me The Lake Erie & Oregon Railroad http://www.geocities.com/seventysixinchesoffun/ "Rose has gotten a bad rap because too many people drink it with their clothes on." -John McPherson > This sounds like a small step in the right direction, but still not as > authentic as what could be done. Let's hope someone continues to evolve > the idea into something more in line with the TAT-IV capabilities. About the only thing I can think of that isn't "real" enough is that you can't apply the brakes while the throttle is above 00%. What else do you want it to do? Oh, and what's a TAT-IV? I've used PSI throttles in the past (my club used them) which had momentum, service brakes, etc. Is the TAT-IV like that? Paul A. Cutler III ************* Weather Or No Go New Haven ************* >> This sounds like a small step in the right direction, but still not as >> authentic as what could be done. Let's hope someone continues to evolve [quoted text clipped - 5 lines] > past (my club used them) which had momentum, service brakes, etc. Is the > TAT-IV like that? The TAT-IV (True Action Throttle Version 4) was developed by Linn Wescott. An article on constructing one appeared in the 3/69 MR. As I mentioned previously, braking was applied separately with a brake handle with several positions that replicated those of an actual locomotive brake stand. The original was a large, fascia mounted unit, but I think a handheld controller with a throttle knob and brake handle with multiple positions could be manufactured. Unfortunately I can't find a really good article about it online, just some minor references. SignatureRick Jones Remove the Extra Dot to e-mail me The Lake Erie & Oregon Railroad http://www.geocities.com/seventysixinchesoffun/ "As the Chinese philosopher, Unconscious, once said, 'It is better to have loved and lost then never to have seen Lost > The TAT-IV (True Action Throttle Version 4) was developed by Linn > Wescott. An article on constructing one appeared in the 3/69 MR. As I [quoted text clipped - 5 lines] > Unfortunately I can't find a really good article about it online, just > some minor references. The TAT-IV offered controllable rate acceleration, adjustable starting voltage, pulse power with adjustable pulse width and frequency square wave pulses that automatically diminished as the filtered DC main power increased, and a five position brake (run-release-service-quick service-emergency). It was great for realistic operation, and for overcoming the shortcomings of open-frame motors. A version of the TAT-IV throttle was offered for several years as a HeathKit - the RP-1065. Heath offered a remote - the RPA-1065-1, but it used a heavy 12 conductor cable so that only a CA or ex-MN governor would not tire holding it through an entire op session. I made a simple mod to mine that sacrificed the 5 position remote brake switch and the throttle pot, and made a remote with accelerate and decelerate buttons mounted in a used vitamin container that worked with a lighter 4-conductor cord. Geezer On 5/5/2008 7:17 PM Geezer spake thus: > The TAT-IV offered controllable rate acceleration, adjustable starting > voltage, pulse power with adjustable pulse width and frequency square wave [quoted text clipped - 10 lines] > pot, and made a remote with accelerate and decelerate buttons mounted in a > used vitamin container that worked with a lighter 4-conductor cord. You don't happen to have a circuit diagram (or a link to one) that you can post, do you? I'm curious how this ancient piece of linear (i.e., non-digital, non-switching) electronic equipment worked. SignatureThe best argument against democracy is a five-minute conversation with the average voter. - Attributed to Winston Churchill On 5/13/2008 12:00 PM David Nebenzahl spake thus: > You don't happen to have a circuit diagram (or a link to one) that you > can post, do you? I'm curious how this ancient piece of linear (i.e., > non-digital, non-switching) electronic equipment worked. Hmm; looks like a guy would want to get a copy of the March 1969 issue of /Model Railroader/. Anyone happen to have one handy? SignatureThe best argument against democracy is a five-minute conversation with the average voter. - Attributed to Winston Churchill > On 5/13/2008 12:00 PM David Nebenzahl spake thus: > [quoted text clipped - 4 lines] > Hmm; looks like a guy would want to get a copy of the March 1969 issue > of /Model Railroader/. Anyone happen to have one handy? I have the magazine, but lack a scanner. The article and schematics are spread over multiple pages. SignatureRick Jones Remove the Extra Dot to e-mail me I am Monica Lewinsky of Borg. You will be assim-mm-mmmm-slurp! >> This sounds like a small step in the right direction, but still not as >> authentic as what could be done. Let's hope someone continues to evolve [quoted text clipped - 5 lines] > past (my club used them) which had momentum, service brakes, etc. Is the > TAT-IV like that? Yes, with separate throttle and brake controls. The brake handle has multiple positions similar to a prototype brake stand on a locomotive. A pushbutton to apply brakes just isn't the same IMHO. SignatureRick Jones Remove the Extra Dot to e-mail me I am Monica Lewinsky of Borg. You will be assim-mm-mmmm-slurp! > Yes, with separate throttle and brake controls. The brake handle has > multiple positions similar to a prototype brake stand on a locomotive. A > pushbutton to apply brakes just isn't the same IMHO. It is when your operating with walk around throttles, switching industries and handling car-cards and waybills at the same time. -- Cheers Roger T. Home of the Great Eastern Railway at:- http://www.highspeedplus.com/~rogertra/ Latitude: 48° 25' North Longitude: 123° 21' West > Yes, with separate throttle and brake controls. The brake handle has > multiple positions similar to a prototype brake stand on a locomotive. A > pushbutton to apply brakes just isn't the same IMHO. Ok, so it's more the interface you're looking for. One can get realistic results these days with DCC and air braking, but the interface is not up to prototype standards by any means. Hmm... I'm thinking something like the Digitrax DT400 throttle, but with the second cab encoder knob replaced with a brake handle. Maybe replace the other throttle with an 10-position rotary switch that would emulate the 8 throttle notches, plus Idle and Off. Hmm... BTW, that is one baaad sig you got there. :-) Paul A. Cutler III ************* "The Internet is like a herd of performing elephants with diarrhea ---- massive, difficult to redirect, awe-inspiring, entertaining, and a source of mind-boggling amounts of excrement when you least expect it." - Anon. ************* >> Yes, with separate throttle and brake controls. The brake handle has >> multiple positions similar to a prototype brake stand on a locomotive. A >> pushbutton to apply brakes just isn't the same IMHO. > > Ok, so it's more the interface you're looking for. Well, the interface coupled with the functionality. The thing that intrigues me is rooted in a description an author gave of using a transistorized throttle on Whit Towers's Alturas & Lone Pine. The article was in MR in the late '60s I believe. To lazy to dig and find the exact year and month ATM. In the article he described having to bring his train into a siding for a meet. The train was nearly as long as the siding IIRC, so he had little room for error. Don't apply enough brakes and you overshoot the siding in front of the opposing train; too much brakes and you won't clear the end of the train or possibly wind up with some (virtual) flat wheels. Anyone playing MS Train Simulator knows the feeling of stopping short or overshooting the correct position for taking on water from the tank or spout while manipulating the brake handle. That's the realism I want in a DCC throttle. SignatureRick Jones Remove the Extra Dot to e-mail me I am Ronald McDonald of Borg. Would you like fries with your assimilation? > >> > Video of very nice, and very skillfully controlled, B-29 and X-1 > >> > models. [quoted text clipped - 35 lines] > Cheers, > John The model train problem is more one of friction than mass. Our bearings have proportionately more stiction and friction than the real ones. In particular, overcoming stiction is far greater than for the prototype, so our trains leap from zero to an unrealistic speed very quickly. If you add momentum effect to your controller then scale speeds mixed with foreshortened tracks is quite taxing to operate. Greg.P. |
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