Metrication advocates are at it again

And about seven gallons in a cubic foot. For some reason that number sticks with me.

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

There's a good reason to switch to metric, right there. I'm always getting tangled up when I'm driving somewhere and I have to convert miles to inches.

Ed Huntress

There are still some along I-5. Sue

Farther north than that. I live in Los Banos (yeah, where's that? - About 70 miles NW of Fresno and 6 miles off of I-5 - several hundred miles north of Mexico) and there are some in this area on the highway. Sue

"JTMcC" wrote in message news:LwKJb.33162$ snipped-for-privacy@news01.roc.ny...

The dumbest part of the whole thing, other than the fact that it makes everything more expensive to build but what the heck it's not their money, is that they spec steel products ( pipe, angle iron, plate, channel, beams, ect. ) in metric measurements, knowing full well that the contractor can't but those items, and will have to convert those dimensions and of course they have to include on every print, several metric designations that fall directly in between the available material sizes leaving the contractor to wonder which way to go, and trying to drag a timely answer out of the government buearocrat/engineer means your 45 day job now is being turned into a 90 day, money pit tying up every resource available for as long a time as possible. A few years ago a state DOT guy was telling me how he really wanted to start his own business. I told him he didn't have a prayer. Those guys do everything the opposite of a for profit private sector company. What I call overhead, and strive to keep a small a number as possible meaning a little more profit (or a little less loss), they call a budget and work at increasing the number as their importance increases proportionally with it. When I try to use manpower efficiently, they want to hire as many people as possible, again, it makes their department and themselfs more important. Their goal is to do a job with the maximum number of people as possible, and to spend as much as possible. Exactly 180 degrees out from the real world. Rant somewhat over now .

JTMcC.

HI, Back in the late 70's or early 80's, there was a newspaper article about a manufacturer of some kind of industrial equipment. After a series r of small design changes the machines was starting to be kludgy, so the company decided to clean things up. And metrify the machine ( mostly bolts and such ). Previously they had sold zero units outside the US. Shortly after the metrified unit hit the market, several foreign companies called and asked to buy. This was with no foreign marketing. When asked about their sudden interest, the foreign companies all said, the machine with English parts would be vitually un-maintainable for them. Try buying a 9/16's bolt in France.

Any company that wants to sell internationally knows that it has to use metric.

Thanks Roger Haar

Like I said," a useless number ", it has no practical use by 99.9% of the population.

Greg H.

Not necessarily true, if the tolerances are so loose that the engine spends part of it energy fighting ageist it's self, or just moving parts around, that didn't provide useful work, you loose energy due to slop.

Look at the difference between the main engines on a Saturn IV and the Space Shuttle, the engines on the Space Shuttle are fine tuned, with tight tolerances. I have heard it said that if the main engines on a Saturn IV, were held to the same tolerances as those on the Space Shuttle, it would produce more thrust with less fuel.

Much the same thing could be said about the differences in military jet fighters, of the USA and the former USSR during the cold war, you get what you pay for with close tolerances, you can go for the fine tuned precision or brute force. The USA tended to go for the fined tuned precision route, the former USSR tended to the brute force approach.

Greg H.

I have no idea.

Greg H.

I have heard allot of speculation as to what the Merlin, that the P-51 got, would have done for the P-38, had it replaced the Allison's that the P-38 used. Have you heard anything like that?

I have heard some War Bird enthusiast and some former WW2 pilots speculate that it would have been better than the P-51.

Greg H.

Originally the P51 had a different engine, I think it was the allison. Somebody in england was flying a prototype, and said 'hey, I know what to do with

In went the merlin, and next thing ya know, 'ol mr. goebbels says "war's over!"

Jim

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That's why I keep hearing the "Look what it did for the P-51, what if they put they put the Merlin in the P-38 question?", and personally, I can't help but wonder myself.

Greg H.

I still maintain that it is the allowances that are loose, not the tolerances. CLass 5 and Class 9 bearings can have the same nominal dimensions - it's the tolerances that are different. If you tighten up the allowances, you have to tighten up the tolerances to prevent excessive slop or binding, but it is possible to have increadably tight tolerances and real sloppy allowances, which lead to very costly machines that don't perform well. Think of using a jig grinder to put in holes that have

One easy-to-remember equivalent is 320 rods per mile. Carry your canoe and gear over a few 40, 60, or 80-rod or longer portages in the boundary waters and you quickly get a good feel for the distance.

The only drawback to this is remembering the 5.5 yard, or 16.5 feet, length of a rod. "One canoe length" is good enough on the trail. But if you want to use rods around the shop, you'd probably have to go to a specialty supplier (don't know of any offhand at the moment) and buy some gauges calibrated in microrods.

-jiw

I'll remember that! You never know when you'll have to convert something to rods, furlongs, or whatever...

My one-man canoe is 13'2". It will never do.

Google is your friend. Just enter the conversion you want, like foot/rod and out pops the conversion.

It will also automagically convert British units like furlongs/fortnight to something useful like m/s

Dick

Never heard of Saturn IV ??

I have heard of Tital IV and I remember the Saturn V

SSME's are cryo engines, nothing in common with the F-1

It is up to the designer to specify engine clearances, and the tolerances required to keep them within acceptable limits. High performance engines typically use larger clearances to reduce friction losses. If the tolerances are ill chosen so as to allow a stack up which results in tight clearances, the engine will produce less power. It may even fail catastrophically. But this is a design fault if too large tolerances are specified, a manufacturing and quality assurance problem only if the specified tolerances aren't maintained on the shop floor.

Actually, it is the fact that the SSMEs burn hydrogen/oxygen with an ISP of 455 while the Saturn F1 engines burned kerosene/oxygen with an ISP of about 270 which makes the difference in thrust efficiency of the two different engines. In other words, it isn't increased precision, it is the major difference in the chemical kinetics of the two fuels which makes the performance difference.

One way to picture this difference is to consider the F1 a diesel truck engine while the SSME is a nitromethane burning dragster engine.

Soviet doctrine was to have overwhelming numerical superiority on the battlefield. That meant their aircraft had to be inexpensive to produce and simple to maintain in the field. Yet even so, their SU-27 outperformed most western aircraft in speed and maneuverability. (The fact that they had the world's largest supplies of titanium didn't hurt.)

Western aircraft excelled in superior avionics and stand-off weaponry. This gave them the ability to engage several targets at once, and to avoid dogfights where their lesser flying performance would be a disadvantage. Of course this also ran up their cost tremendously, so the Western powers could only afford about a fraction of the number of aircraft as their Soviet opponents, even though the West was much richer, and spent many times as much money on them.

Soviet Cold War doctrine was never tested on the battlefield. We'll never know if their approach of sending 5,000 front line Soviet aircraft against the 600 or so front line Western aircraft would have been successful or not. The only experience we have is from the Mideast wars, where a handful of planes from both sides battled. In those cases, the superior avionics and stand-off weaponry of Western aircraft prevailed. But we don't know if they could have actually handled forces outnumbering them 10 to 1 in the air.

It should also be noted that Russian rocket engines have a long record of performance, reliability, and *cost effectiveness* far in excess of that of comparable US rocket engines. In fact, future US rockets, such as the OSP, may use Russian rocket engines (unless that deal is killed for political reasons).

There's much good to be said about simple, *robust*, and cost effective design when it comes to high energy propulsion systems.

Gary

Wayne Lundberg wrote

That might be true in a free market, but the market is not free. It is distorted by billions of dollars of taxpayer funded contracts.

For example, Nasa and the US military specify metric units in contracts. This provides a financial incentive for their suppliers to increase the adoption of metric.

In contrast, taxpayer funded civil construction (roads etc) contracts are specified in non-metric units. This provides a financial incentive for their suppliers to continue their use of non-metric units.

You have not served have you? If you had, you would know that the military uses metric. Feel free to tell a group of American soldiers that they are socialist elite lunatics.