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The Machine that goes Ping

StukaFox (Member Profile)

newtboy says...

Lol. I've done similar at that turn in my Civic with super wide tires, it was a go-cart, totally rode on rails, but that turn had the rear end hanging out and the front tires smoking. I also got pulled over doing 110, but on the straight right after the turn, just before the artichoke fields. The cop asked didn't I think over 80 was a bit fast, I said yes, he let me go. I was so lucky. Should have lost my car.
Then there was the Acura Legend I inherited...the Speedo topped out at 150, but the car sure didn't. I think I got it to around 175 based on rpm calculations. Ahhh, to be young and stupid again. Crashed it into a K rail at 55 mph, went airborne. Good times!

StukaFox said:

I love 84!

I had some friends into exotic cars and we'd take 84 over to the coast now and again, mostly because we had a shit-ton of money and a shit-ton of spare time to kill -- the Dot-Com fucking rocked!

There's a bend in the road just outside La Honda on the coastal side that's a 15mph hairpin with a tree at the apex. It's a lovely goddamn thing, especially when you forget it's there. So here we all come, lane-trading and exercising general assholery in cars that cost what a nice single-family home does.

Oh FUCK, the turn!!

My friend in the 911 does this beautiful trail-brake and swings through the curve. Elise follows suit, complete with smoking tires. Next up is Countach. He BARELY holds it together, but gets through without any real drama.

Now it's my turn.

Did I mention I was driving a '97 Camaro Z-28? Yeah, Camaros of that year are good at exactly one thing: driving very fast in very straight lines. Corners? Yeah, not so much. I realize I'm in trouble and I'm coming into the turn WAY too fast. I grab the shifter and get ready. My plan is that I'm going to slam it into first, let the rev limiter do its thing to save the engine, pull the e-brake and swing the tail, then punch it and swing the ass-end around and launch out of the curve with smoking Z-rated tires and all!

And HERE WE GO -- grab the shifter, yank it all the way down and...

That's when California emissions standards fucked me.

You see, when you buy a Camaro Z-28 in California, you don't actually get first gear. You get what's called a California First, which is actually SECOND gear, because if you were actually able to use FIRST gear, the goddamn car would belch enough emissions to make a farting Brontosaurus blush. And second gear ain't exactly gonna work for my little plan.

tl;dr is that I hit the no-lock brakes hard enough to get my speed down and was able to bring the ass around with the little e-brake trick. I wasn't out of the woods because I over-corrected on the way out and spun. The same God that I spite and don't believe in actually saved my ass and I didn't end up going off the road. Apparently, he loves fools and Z-28 Camaros.

I honestly had more fun in that car than the law allows: sometimes literally, like when I got clocked at 110 coming onto the straight at King City. Good times, man, good times.

How it Starts

BSR says...

Ya need a new line. That's so late 70's. "Hook, line and sinker" went out with 78 rpm vinyl records too. Think man. Think. Don't be a parrot.

bobknight33 said:

I realize you are a leftist liberal nut and that you not only drank the Kool Aid but you are guzzling it down.

Now we can even bowl from the couch

bremnet says...

Oops. Sorry folks... didn't dig enough for the origin. Thanks Crushbug. Kind of wondered about the how much force would be required to hold the ball at that rpm, but fell for it.

BSR said:

spoileralert

bobknight33 (Member Profile)

It's good to be the King!

Spinning Hologram Demo

Ever See a CT Scanner at Full Speed?

Largest Turboprop in the world Antonov AN 22 Manchester

radx says...

Counter-rotating propellers sparked my curiosity when I first saw them on a British Seafire Mk46 at a flight show in the early nineties.

So my amateur's answer would be that it's about the problem of turning the engine's power into thrust. With increasing power, you can either increase the propeller's RPM or its area. So you either a) spin it faster, b) increase its diameter, c) use a more favourable blade geometry, d) add more blades.

a) and b) both lead to blade tips moving faster, and once they approach the speed of sound, wave drag sets in and ruins your day. b) also runs into issues in terms of ground clearance. Thus the Kim Jong-un blades on planes like the An-70: short and fat.

c) is rather difficult to do in terms of manufacture -- that's why more pronounced blade shapes are a relatively recent development.

d) on a single propeller decreases the efficiency of each blade as it passes through the previous blade's vortex. That's why, for instance, German planes in WW2 almost exclusively relied on 3-bladed propellers with increasing blade size, whereas Supermarine went to four and even 5 blades rather quickly. You can work the issue to a certain degree by modifying the blade geometry, thus the 8 blade props on a modern A400M.

Adding more blades by adding another propeller gets around d), although the aft prop still loses efficiency compared to the front prop. On the other hand, counter-rotating props massively reduces problems with torque, which can be rather horrendous for single engine prop planes. The Bf 109, for instance, is (in)famous for being difficult during take-off as it pulls to the side quite violently.

moonsammy said:

I don't know enough about aerodynamics to understand how stacking the propellers like that makes any sense, so I'm just going to assume it's some sort of Soviet technomagic.

Vox explains bump stocks

harlequinn says...

"First you claimed .2 second split is 300 rpm, now you say it's 90rpm. I'm so over this. Have fun at the range. "

Ahh I see the confusion. I should have been clearer.

I'm reporting two different rates - max theoretical, and actual with aiming and magazine changes.

So using splits alone on an unlimited mag, 0.2 split is 300 rpm.

Using that same 0.2 split with fixed aiming time of 1 second per target and two mag changes (30 round mags) you'll get approximately 90 rounds per minute actual.

Etc. as per my other examples.

It's good to hear you've been shooting that long. If you've been doing it that long you must still enjoy it - which is great.

newtboy said:

I mixed up your two fire rates (.2 and .12) still you said you can keep up 5rps for many minutes (10 for a short time) not 3...."My lazy firing rate has splits (time between shots) of approximately 0.2 seconds. I can do that for a long time (many minutes before I slow done). That is a rate of 300 rounds per minute. My fast splits are approximately 0.12 seconds. I can't do that for very long (probably one magazine). That is a rate of 600 rounds per minute." And that's only really 300rpm if you have a 300 round mag.

....wait...why am I wasting my time on this? It's clear you're not comparing Apple's to Apple's.
You didn't come close to convincing me that manual 120 shots per minute at 400 yards all well aimed is believable...even belt fed. Keep in mind he actually averaged hitting one moving person in the dark at 400 yards per second for 10 minutes. Your generous competition numbers have you double tapping at 45 targets per min (without a hit rate given, or range).

First you claimed .2 second split is 300 rpm, now you say it's 90rpm. I'm so over this. Have fun at the range.
Again, the target was the crowd. He got more lead on that target on auto. No aim needed.
I've been shooting (non competitively) for 40 years btw, after rifle marksmanship courses for 3 years starting at 7...but thanks for the suggestion.

Vox explains bump stocks

newtboy says...

I mixed up your two fire rates (.2 and .12) still you said you can keep up 5rps for many minutes (10 for a short time) not 3...."My lazy firing rate has splits (time between shots) of approximately 0.2 seconds. I can do that for a long time (many minutes before I slow done). That is a rate of 300 rounds per minute. My fast splits are approximately 0.12 seconds. I can't do that for very long (probably one magazine). That is a rate of 600 rounds per minute." And that's only really 300rpm if you have a 300 round mag.

....wait...why am I wasting my time on this? It's clear you're not comparing Apple's to Apple's.
You didn't come close to convincing me that manual 120 shots per minute at 400 yards all well aimed is believable...even belt fed. Keep in mind he actually averaged hitting one moving person in the dark at 400 yards per second for 10 minutes. Your generous competition numbers have you double tapping at 45 targets per min (without a hit rate given, or range).

First you claimed .2 second split is 300 rpm, now you say it's 90rpm. I'm so over this. Have fun at the range.
Again, the target was the crowd. He got more lead on that target on auto. No aim needed.
I've been shooting (non competitively) for 40 years btw, after rifle marksmanship courses for 3 years starting at 7...but thanks for the suggestion.

harlequinn said:

"You said almost 3 times that speed, continuously for over 10 minutes....and not with a lightweight speed shorting pistol."

You are not making any sense. I see what I wrote but it is unclear what you are referring to. You are welcome to quote the part you are referring to.

As I wrote above, you can choose the length of time you are aiming your firearm for. I even gave a comparative set of aiming scenarios.

I love how you take the top end of my approximation as your "laughable" scenario and don't mention the rest of the range (i.e. 50 rounds per minute with mag changes). Could you shoot at one round per second aimed? I think with a little training you could.

Doing 0.2 second splits (i.e. you shoot twice at each target) and taking about a second on every target, using 30 round mags, you can do 90 round per minute without much trouble. Going a little slower, say 0.3 second splits, and taking 1.5 seconds per target you can do about 60 round per minute. I could go on. The point is, these are aimed shots with a higher chance to hit the target, and with just as much chance to accidentally hit another target on a miss. This has the result of more hits on target.

"you get more hits on target in full auto".

No, you don't. On target means a hit near the point you intended on a target. He was getting random hits - as is evidenced by the low fatality rate versus high injury rate. The only way you would be correct was if you argued that he intended non-fatal injuries as much as he intended fatalities (and you're welcome to make that argument - it has some merits depending on what this lunatic was trying to achieve).

"If it's as common as you say, that should be easy to provide with a comparison video instead of a suggestion to buy and read a certain book. The videos I found are all short range small target, not at all the same as what we're debating. Show me a comparison of a field layered deep with 10000 balloons getting shot at from distance, that would be informative, short course accuracy target shooting isn't."

The book is good because it shows military statistics with full-auto versus other fire modes. Books are often better than videos. It also outlines military teaching methodology, include marksmanship and how it evolved over time. Full auto is still used in military engagements but you'll find it is used very sparsely (here is a good thread of military and ex-mil talking about it's uses: https://www.quora.com/Why-do-militaries-use-assault-rifles-when-the-full-auto-feature-is-rarely-ever-used )

Short range targets are easier to hit. Are you trying to prove my point? Long range targets are harder to hit. Your rate of randomly hitting targets does not get better at longer ranges. But aiming does increase your chance of hitting a target at any range.

If you really wanted to do a comparison at that range then the targets would be a lot larger than balloons.

You're arguing against established marksmanship knowledge that is readily available over the internet or in firearms courses.

I think you owe it to yourself to prove yourself right or wrong by doing some rifle marksmanship courses. Approach it as a sport and you'll have a lot fun doing it!!!

I can't chat much longer - thanks for the good discussion!

Every Song of the Summer Since 1958

U2 "Two Hearts Beat As One" 1983

lurgee says...

War was the album where I started. I bought everything before it. I have at least 3 remixes of this song. One is a unreleased promotion 12" 45 rpm. Remained a huge fan until Unforgettable Fire which is my favorite album. I also have 3 U2 4Play packs(4 45 rpms). One containing some tracks yet to be released digital from their Boy era.

Cyclist Uses Aerodynamics Over Leg Strength

Khufu says...

I don't see a motor... there is no derailleur because he is riding a fixed-gear bike. you can also tell from the way the back wheel meets the frame (axle hole has wheel insert from back and is tightened to desired chain tension).

He probably avoids pedaling down fast decents for this very reason. rpm gets so high it no longer helps to pedal. I see people on fixies riding up and down mountains in my area, the real impressive part is how they climb UP the mountain in such a big gear.

song77 said:

Motorized, no derailed, and he had to slow the bike down to put his cleats back in . Made skillz in planking thou i wouldn't have the guts to do that

Blower impeller design experiments

Drachen_Jager says...

Huge huge miscalculation on his part here.

Electric motors all have efficiency curves which show the efficiency (power output to power input) relative to the RPMs of the motor. Without addressing that, the rest of this experiment is meaningless. If he tested it on ten different motors he'd come up with ten completely different results.

What he SHOULD have done was to use a motor that he can fix the RPMs, adjust it to the peak efficiency RPMs for each setup and then measure windflow and power consumption. That would give him some numbers he can use.



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