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!
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.
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.
You can only do so much with caulk, cardboard, and duct tape.
To email me directly, send a message to puckdropper (at) fastmail.fm
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.
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?
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
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
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... ;-)
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.
On Thu, 01 May 2008 11:55:24 -0400, Wolf Kirchmeir wrote:
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.
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
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.
Nope, but you score extra points for knowing a couple of generic musician
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
Good for Doc.
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.
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
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.
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