Author Topic: Cruising at 120 km/h  (Read 2055 times)

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AzCal Retred

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Reply #30 on: December 17, 2020, 07:11:25 pm
Zimmemr - my Electrical Utility Union experience parallels yours. A good Union takes work & member support. Lots of workers somehow believe the company gives up those benefits out of the goodness of their hearts. Ben Franklin's "Hang together or hang separately" doctrine really applies. On the Railroad I got to experience a "Company Union" and was not impressed. It was "the best Union the Company ever had...".
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zimmemr

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Reply #31 on: December 17, 2020, 10:18:24 pm
Zimmemr - my Electrical Utility Union experience parallels yours. A good Union takes work & member support. Lots of workers somehow believe the company gives up those benefits out of the goodness of their hearts. Ben Franklin's "Hang together or hang separately" doctrine really applies. On the Railroad I got to experience a "Company Union" and was not impressed. It was "the best Union the Company ever had...".

I hear you brother. We went through some very tough times when we elected a real low life to run our local. Pretty soon he had a new caddy and we  lost benefits, overtime and saw our jobs farmed out to scab contractors. Fortunately for us, he pulled one of those  "If you walk out on me I'll kill myself" stunts with his wife. She kept walking and to the surprise of all of us he turned out to be true to word. Our next president and his board got thing turned around and even though I retired on the last day of the current contract. The one he and his crew negotiated turned out to be a good one. I was in IBEW local 420, it was an "inside" local at Connecticut Light and Power Our traveling local is 42, were you IBEW?
« Last Edit: December 17, 2020, 10:21:45 pm by zimmemr »


Richard230

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Reply #32 on: December 17, 2020, 10:22:37 pm
The municipal worker's union that I was forced to join (what they called a "closed shop"), had meetings that were a joke. Everyone sat around in the DPW lunchroom and drank "Irish" coffee and complained and joked about their "stupidvisors". When it came time to elect officers, the only people who were nominated were the members who didn't show up to the meeting. Everyone always tried to show up for the election meeting so that they could decline the job if they were nominated.   ::)  The union really didn't do much other than spending a year on city time during the day negotiating a new contract.  ???
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AzCal Retred

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Reply #33 on: December 17, 2020, 11:42:58 pm
UWUA & IBEW both over time: San Onofre, Mohave GS, Bishop and Big Creek Hydro, and some time in Transmission. The young guys don't really believe how underhanded the company can be, they often just see the letterhead on the paycheck and assume they are valued. There's always a tough learning curve. The membership makes the Union, when they don't care & pay attention, things fall apart.
A brace of 1999 Bullets: 1 Red Deluxe, 1 Green Standard. Also, 1 wee orphan 1956 Fire Arrow project.


zimmemr

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Reply #34 on: December 18, 2020, 12:51:51 am
UWUA & IBEW both over time: San Onofre, Mohave GS, Bishop and Big Creek Hydro, and some time in Transmission. The young guys don't really believe how underhanded the company can be, they often just see the letterhead on the paycheck and assume they are valued. There's always a tough learning curve. The membership makes the Union, when they don't care & pay attention, things fall apart.

We're on the same page my friend. Exactly the same page.


ace.cafe

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Reply #35 on: January 03, 2021, 04:16:43 am
Pomeroy Dictum for engine longevity.
2500 fpm avg piston speed limits during normal use.
90mm stroke at 2500 fpm = 4250 rpm cruising rpm.
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gizzo

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Reply #36 on: February 11, 2021, 09:05:09 am
Is it true meteor 350 cannot cruise at 120 km/h  ???

It'll do it at redline in first.

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gizzo

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Reply #37 on: February 11, 2021, 09:07:37 am
There's always the Jawa Perak for comparison. 6 speeds. 30 HP at some undisclosed RPM, I'm guessing maybe 8500-ish? It HAS to spin more than the Meteor to develop 50% more power (on paper, at least). Price is about 15% more than the Meteor. Mileage seems to be in the 28-32 Km/L range, probably more often 65 MPG mostly as kids of all ages will be exploring the powerband more thru that 6-speed box. Car 'n Bike think it'll run 125/75 pretty reliably, (DriveSpark is thinking 150-160 KPH (90-95 MPH) which squares with maybe 28-30 HP. It will definitely be more "frantic" than the Meteor. That 6-speed may possibly mean it's a bit "cammy". Keef Sparrow & Derottone have made a good point about market suitability. The Perak would certainly be suited for the US market where we don't mind rowing the shifter a bit. The Kamikaze Ninja 250/300 is proof of that. Derottone's other point about MPG seems borne out also, a possible 65 MPG for the more muscly Perak against a probable 85 MPG for the more laid back Meteor.

https://www.carandbike.com/reviews/jawa-perak-first-impressions-2192708#:~:text=The%20Perak%20is%20a%20factory%2Dcustom%20motorcycle%2C%20and%20India's%20most,capacity%20engine%2C%20with%20more%20performance.

https://www.drivespark.com/two-wheelers/2019/jawa-perak-top-speed-mileage-seating-height-exhaust-bookings-deliveries-more-029879.html
Jawa Motorcycles are yet to share any official performance figures of the Perak motorcycle. However, considering the power output and weight, we expect it to come with a top speed of around 150km/h to 160km/h. Mileage & Fuel Tank Capacity The Jawa Perak comes with the same fuel tank as the Jawa and Jawa 42 motorcycle. This includes the same 14-litre tank capacity as the others. However, with slightly higher displacement and power output from the engine, we expect the Perak to return a lower mileage figure than the other two models. The fuel efficiency figures of the Jawa Perak will be in the range of 28 - 32km/l.
Read more at: https://www.drivespark.com/two-wheelers/2019/jawa-perak-top-speed-mileage-seating-height-exhaust-bookings-deliveries-more/articlecontent-pf106935-029879.html


Those comparisons are worthless. Indian media just makes shit up based on whatever they think will make them sound like they know what they're talking about. Probably got something to do with monetization.
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derottone

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Reply #38 on: February 12, 2021, 01:04:23 pm
Pomeroy Dictum for engine longevity.
2500 fpm avg piston speed limits during normal use.
90mm stroke at 2500 fpm = 4250 rpm cruising rpm.

Is there more to the Pomeroy Dictum? Never heard of it, 2500 fpm seems like a relatively slow piston speed.
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ace.cafe

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Reply #39 on: February 12, 2021, 04:41:15 pm
Is there more to the Pomeroy Dictum? Never heard of it, 2500 fpm seems like a relatively slow piston speed.
It was a guide for normal vehicles, not racing, and it was many years ago. However, it is still quite applicable for road vehicles even today, and many vehicles still conform, even though they don't define it as Pomeroy.


Famous British engineer.
https://en.m.wikipedia.org/wiki/Laurence_Pomeroy

Article.
https://www.google.com/amp/s/www.roadandtrack.com/new-cars/car-technology/news/amp10953/nascar-would-have-pomeroy-spinning/

« Last Edit: February 12, 2021, 04:54:11 pm by ace.cafe »
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derottone

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Reply #40 on: February 12, 2021, 06:24:44 pm
Interesting, always good to have a rule of thumb.
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AzCal Retred

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Reply #41 on: February 12, 2021, 06:34:38 pm
An article by the noted Kevin Cameron referring to engineer Laurence Pomeroy. Easily found information with a simple search.
 Also kudos to Ace by bringing up Pomeroy in this forum 12 years ago in this forum.
Let's discuss Piston Speeds on: March 14, 2009, 05:08:43 pm
" A long time ago, there was this automotive engineer by the name of Laurence Pomeroy.
He came up with a standard called the "Pomeroy Dictum". The Pomeroy Dictum states that for good longevity, the piston speeds in an internal combustion engine should remain under 2500 feet per minute.
Okay that's a relatively older standard, but it's still relevant, and it was an accepted premise when the Bullet engine was originally developed in the 1940s/50s. "


Kevin Cameron
Shouldrace bikesbe purpose-builtor heavilybasedon productionbikes?
Motorcycle Sport & Leisure3 Jun 2020Kevin Cameron
Should race bikes be purpose-built? Kevin Cameron looks at the longstanding argument.

When the Isle of Man TT road races resumed in 1920after the Great War,the general assumption was that this was still a test of endurance among well-prepared production bikes - literally a Tourist Trophy event. If primitive belt-rim or caliper brakes functioned poorly, too bad! It would be un-sporting to fit nonproduction brakes that actually worked.

Yetit was also clear that success on the Island sold a lot of motorcycles, such that sourpuss makers like Triumph and BSA,normally devoted to selling lowpriced utility bikes, were tempted to give it a try.

In engines, the sharp point of technology was overhead valves. But Laurence Pomeroy's dictum applied in 1920: "The first instance of novel principle is invariably defeated by the developed example of established practice:' A side-valve Sunbeam won the Senior TT in 1920, despite Douglas's head start with OHV (they'd built one in 1913) and AJS'scertainty that OHV was the future. Alec Bennett's 1922 Senior win on a Sunbeam would be the last in class by a side-valve.

The following year Douglas got it right and the revolution appeared unstoppable as their bikes were 1-2-3-4 on the first lap. One by one they stopped, leaving local man Tom Sheard to win on the highrevving OHV Douglas flat twin.

It was tempting to take the moral high ground by running useless stock brakes and flexy pre-war chassis in the TT, but it was becoming clear that misguided morality did not win races. 'Pa' Norton famously threatened to fire any rider who raced with other than the jerky, short-travel Druid girder fork.

But riders see clearly what better ideas can do. Graham Walker fitted a longer-travel Webb fork with friction damping - and went faster. One by one, the other riders followed his example.

When Walter Moore was hired to make a winner of Norton's OHV 500, he saw it was crippled by nearly useless stock brakes. As British Hub, the usual supplier, could do nothing before the TT, Moore adapted brakes from Ford cars.

When crankpins wallowed loose in soft cast-iron stock engine flywheels, what was a moralist to do? No new bikes would be sold by crowing that their parts, proven inferior in performance, best fit the spirit of the rules. This made the choice a simple one: either race to win or don't race at all. Cast iron flywheels were replaced by heat-treated carbon steel equivalents.

AJS and Velocette saw the value of overhead cam (OHC, but it took them time to make it work. Douglas and Sunbeam both made OHC experiments, but without success. To make bikes finish races, a lot of testing was necessary, and there was a need for development engineers with racing experience. Hire one of the top men and, like it or not, your results improved. Racing was no longer just sporty flat-cap riding on standard bikes. When you fixed what broke in this process, your motorcycle naturally evolved into a purpose-built racing machine.

The shortcomings of drip-feed total-loss oiling drove design toward full pumped recirculating oil systems. A total-loss rider, looking back and seeing no smoke, knew it was time to 'give 'er a shot' of oil with the hand pump. Engines rejected such cretinous schemes by tightening and seizing at speed.

First one maker and then another had spurts of TT success. Douglas had no future in racing because there was no way to cool their rear cylinder, sheltered as it was behind the crankcase and magneto. Sunbeam and Rudge had short-term success too, but it was becoming clear that winning required designing to win - not 'careful assembly' of warmed-over production machines with useless brakes and frames that snapped.

Norton eventually accepted this wholeheartedly and the resulting long list of wins drew criticism that they had 'ruined racing'. In 1931, once they'd got their OHC 500 and 350 performing properly, Nortons were first, second and fourth in the Junior, and 1-2-3 in the Senior, ahead of two Rudges.

Did Norton ruin racing? Experience of the present day in MotoGP and World Superbike tells us clearly that they did not. What they did was build the best bike possible under the rules in force. If anyone

'ruined' racing, it was the rules-makers in failing to set limits like those set out in detail for WorldSBK.

Yetbecause this was all happening for the first time in the sport we can't frown too darkly at the rulesmakers either. The 'spirit of the rules' was made clear in 1911 when pedalling gear was banned and multi-speed gearboxes were deliberately encouraged. The role of racing was to bring forth technologies that would raise the capability of the motorcycle for all users.
« Last Edit: February 12, 2021, 06:43:26 pm by AzCal Retred »
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derottone

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Reply #42 on: February 12, 2021, 10:10:02 pm
Thank you for the impressively efficient researching efforts AzCal.  :)
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Richard230

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Reply #43 on: February 12, 2021, 10:16:29 pm
So what sort of fpm do the 73mm-stroke pistons of my BMW R1200R achieve at its 9,000 rpm redline? I would expect BMW to design the engine's maximum engine speed to be rather conservative for running at top speed on the Autobahn. I bet it is more than 2500 fpm.
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ace.cafe

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Reply #44 on: February 12, 2021, 10:38:23 pm
So what sort of fpm do the 73mm-stroke pistons of my BMW R1200R achieve at its 9,000 rpm redline? I would expect BMW to design the engine's maximum engine speed to be rather conservative for running at top speed on the Autobahn. I bet it is more than 2500 fpm.
The Pomeroy Dictum isn't intended to be the redline. It is everyday riding rpm guideline for longevity.
A 500 Bullet hits Pomeroy guidelines at 4250 rpm, but it redlines higher.

To answer your question for 73mm stroke and 2500fpm piston speed, it would be 5250 rpm.
At your 9000 rpm redline the piston speed would be 4311 fpm.

A Bullet at 4311 fpm would be at 7300 rpm.
« Last Edit: February 12, 2021, 10:45:55 pm by ace.cafe »
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