OK, I'm being lazy here

Ike666 · January 29, 2011, 11:07 AM

What is the trans-sonic velocity range in FPS?

dumbodave · January 29, 2011, 11:51 AM

Wikipedia says 1,126 f/sec - at 68 degrees F and presumably at sea level. Altitude, temperature, and even Barometric Pressure can change that figure considerably...

Brian Pfleuger · January 29, 2011, 12:04 PM

I believe the general range is roughly from mach .8 to mach 1.2.

Mach 1 at standard atmosphere and sea level is 1,116 fps, so "transsonic" would be from 892 fps to 1339.

However, that is the area generally used in aviation, where drag begins to increase drastically at the low end up to the point where all airflow around the aircraft becomes supersonic at the high-end.

I assume that a bullet will have a much lower range of speed where the instability would be a problem.

egor20 · January 29, 2011, 12:10 PM

Its faster than the winged velocity of an unladen European Swallow.

Airspeed can also be predicted using a published formula. By inverting this midpoint Strouhal ratio of 0.3 (fA/U ≈ 0.3), Graham K. Taylor et al. show that as a rule of thumb, the speed of a flying animal is roughly 3 times frequency times amplitude (U ≈ 3fA).5

We now need only plug in the numbers:

U ≈ 3fA
f ≈ 15 (beats per second)
A ≈ 0.22 (meters per beat)
U ≈ 3*15*0.22 ≈ 9.9

... to estimate that the airspeed velocity of an unladen European Swallow is 10 meters per second.

Sorry, couldn't resist

carry on, nothing to see here

mehavey · January 29, 2011, 02:35 PM

This is "Trans"sonic.....

The front half of the bird is supersonic.
The back half is subsonic.

Peetzakilla's +/- 20% Mach is a nice round esimate for flow effects in general. But numbers vary dramatically from application-to-discipline:

http://search.aol.com/aol/imageDetai...ary-online.org

But the fighter shot also shows why you want to minimize the chances of your bullet dropping back through this transition if you are looking for long-range precision

Ike666 · January 29, 2011, 02:44 PM

Mehavey

I've had the privilege of seeing that sight at sea (USS Roosevelt) - both by an F-14 and F-18. The 'Cat was by far the more impressive of the two.

Thanks guys - now I can transliterate to my Barn Swallows from that Eurotrash bird!

Brian Pfleuger · January 29, 2011, 02:47 PM

Quote:

Originally Posted by mehavey

The front half of the bird is supersonic. The back half is subsonic.

Well, technically, it's the air that's "half" subsonic and "half" supersonic. That pilot would be having a very bad day if half his plane was faster than the other half!

mehavey · January 29, 2011, 03:16 PM

For y'all's explosive viewing pleasure...
http://www.youtube.com/watch?v=a32z-HZlq1o&feature=fvsr

(More reasons not to have bullets go trans-sonic if you can avoid it.)

Rangefinder · January 29, 2011, 03:26 PM

Quote:

... to estimate that the airspeed velocity of an unladen European Swallow is 10 meters per second.

Yes, but what does that have to do with a 1-pound coconut?

I didn't even get around to asking your favorite color or quest yet!

4runnerman · January 29, 2011, 03:58 PM

to estimate that the airspeed velocity of an unladen European Swallow is 10 meters per second

Awesome movie is was. Could watch it over and over. Cracks me up everytime i watch it

Brian Pfleuger · January 29, 2011, 04:45 PM

Are you suggesting coconuts migrate?

Rangefinder · January 29, 2011, 04:56 PM

Wait--we're getting off-track here. We need to pull it back on-topic a little...

A TRANS-SONIC COCONUT! Now THAT would be something, wouldn't it? Especially if there were a swallow involved...

wncchester · January 29, 2011, 05:03 PM

"The front half of the bird is supersonic. The back half is subsonic."

Hummm...there's an interesting concept in there somewhere.

4runnerman · January 29, 2011, 05:04 PM

A TRANS-SONIC COCONUT! Now THAT would be something, wouldn't it? Especially if there were a swallow involved...

Only if the coconut was being transported by the Black Knight

While chasing the swallow

Rangefinder · January 29, 2011, 05:08 PM

Or... How about a trans-sonic COW!! I want THAT catapult!

Holy-hell, the OP probably thinks we've all gone completely off the deep end...

Ike666 · January 29, 2011, 05:30 PM

Actually, no. What an unexpected treasure trove of tid-bits about trans-sonic, um, objects.

Now, I'm thinking Cat-in-the-Hat... the blur of the red and white strips as he transitions through the compression wave

4runnerman · January 29, 2011, 06:25 PM

Egor started it.Ya ,It's all his fault,,Ya lets blame him,,Shame on you Egor

Brian Pfleuger · January 29, 2011, 07:33 PM

You know how you prove that a coconut is transonic?!

It'll turn you into a Gnut!

(but you'll get better!)

Ike666 · January 29, 2011, 09:54 PM

RANGE YARDS MUZZLE 50 100 200 300 400 500 600 1000
VELOCITY FPS 2700 2602 2504 2314 2132 1951 1778 1617 1117
VELOCITY FPS 2600 2501 2405 2219 2038 1861 1694 1536 1078

So, if I'm understanding this right, the 168 SMK Federal GMM will transition out of supersonic around 958 to 993 yards, and become inherently less stable at those ranges (give standard normal atmospheric conditions).

Coconuts, however, with their substantially better BC will remain supersonic out to about 1100 yards.

Yes?

January 29, 2011, 11:07 AM	#1
Ike666 Senior Member Join Date: October 10, 2009 Location: SW VA Posts: 491	OK, I'm being lazy here What is the trans-sonic velocity range in FPS? __________________ ___________________ "I'm your huckleberry."

January 29, 2011, 11:51 AM	#2
dumbodave Member Join Date: January 30, 2010 Location: Calgary, Alberta Posts: 46	Wikipedia says 1,126 f/sec - at 68 degrees F and presumably at sea level. Altitude, temperature, and even Barometric Pressure can change that figure considerably... __________________ If it's incoming - DUCK!

January 29, 2011, 12:04 PM	#3
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	I believe the general range is roughly from mach .8 to mach 1.2. Mach 1 at standard atmosphere and sea level is 1,116 fps, so "transsonic" would be from 892 fps to 1339. However, that is the area generally used in aviation, where drag begins to increase drastically at the low end up to the point where all airflow around the aircraft becomes supersonic at the high-end. I assume that a bullet will have a much lower range of speed where the instability would be a problem. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

January 29, 2011, 12:10 PM	#4
egor20 Senior Member Join Date: November 14, 2010 Location: Northern Virginia Posts: 1,824	Its faster than the winged velocity of an unladen European Swallow. Airspeed can also be predicted using a published formula. By inverting this midpoint Strouhal ratio of 0.3 (fA/U ≈ 0.3), Graham K. Taylor et al. show that as a rule of thumb, the speed of a flying animal is roughly 3 times frequency times amplitude (U ≈ 3fA).5 We now need only plug in the numbers: U ≈ 3fA f ≈ 15 (beats per second) A ≈ 0.22 (meters per beat) U ≈ 3150.22 ≈ 9.9 ... to estimate that the airspeed velocity of an unladen European Swallow is 10 meters per second. Sorry, couldn't resist carry on, nothing to see here __________________ Chief stall mucker and grain chef Country don't mean dumb. Steven King. The Stand

January 29, 2011, 02:35 PM	#5
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,883	This is "Trans"sonic..... The front half of the bird is supersonic. The back half is subsonic. Peetzakilla's +/- 20% Mach is a nice round esimate for flow effects in general. But numbers vary dramatically from application-to-discipline: http://search.aol.com/aol/imageDetai...ary-online.org But the fighter shot also shows why you want to minimize the chances of your bullet dropping back through this transition if you are looking for long-range precision Last edited by mehavey; January 29, 2011 at 02:53 PM.

January 29, 2011, 02:44 PM	#6
Ike666 Senior Member Join Date: October 10, 2009 Location: SW VA Posts: 491	Mehavey I've had the privilege of seeing that sight at sea (USS Roosevelt) - both by an F-14 and F-18. The 'Cat was by far the more impressive of the two. Thanks guys - now I can transliterate to my Barn Swallows from that Eurotrash bird! __________________ ___________________ "I'm your huckleberry."

January 29, 2011, 03:16 PM	#8
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,883	For y'all's explosive viewing pleasure... http://www.youtube.com/watch?v=a32z-HZlq1o&feature=fvsr (More reasons not to have bullets go trans-sonic if you can avoid it.) Last edited by mehavey; January 29, 2011 at 03:27 PM.

January 29, 2011, 03:58 PM	#10
4runnerman Senior Member Join Date: January 16, 2010 Location: Minnesota Posts: 3,577	to estimate that the airspeed velocity of an unladen European Swallow is 10 meters per second Awesome movie is was. Could watch it over and over. Cracks me up everytime i watch it __________________ NRA Certified RSO NwCP- Performance Isn't Optional

January 29, 2011, 04:45 PM	#11
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	Are you suggesting coconuts migrate? __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

January 29, 2011, 04:56 PM	#12
Rangefinder Senior Member Join Date: August 4, 2005 Posts: 2,017	Wait--we're getting off-track here. We need to pull it back on-topic a little... A TRANS-SONIC COCONUT! Now THAT would be something, wouldn't it? Especially if there were a swallow involved... __________________ "Why is is called Common Sense when it seems so few actually possess it?" Guns only have two enemies: Rust and Politicians.

January 29, 2011, 05:03 PM	#13
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	"The front half of the bird is supersonic. The back half is subsonic." Hummm...there's an interesting concept in there somewhere.

January 29, 2011, 05:04 PM	#14
4runnerman Senior Member Join Date: January 16, 2010 Location: Minnesota Posts: 3,577	A TRANS-SONIC COCONUT! Now THAT would be something, wouldn't it? Especially if there were a swallow involved... Only if the coconut was being transported by the Black Knight While chasing the swallow __________________ NRA Certified RSO NwCP- Performance Isn't Optional

January 29, 2011, 05:08 PM	#15
Rangefinder Senior Member Join Date: August 4, 2005 Posts: 2,017	Or... How about a trans-sonic COW!! I want THAT catapult! Holy-hell, the OP probably thinks we've all gone completely off the deep end... __________________ "Why is is called Common Sense when it seems so few actually possess it?" Guns only have two enemies: Rust and Politicians.

January 29, 2011, 05:30 PM	#16
Ike666 Senior Member Join Date: October 10, 2009 Location: SW VA Posts: 491	Actually, no. What an unexpected treasure trove of tid-bits about trans-sonic, um, objects. Now, I'm thinking Cat-in-the-Hat... the blur of the red and white strips as he transitions through the compression wave __________________ ___________________ "I'm your huckleberry."

January 29, 2011, 06:25 PM	#17
4runnerman Senior Member Join Date: January 16, 2010 Location: Minnesota Posts: 3,577	Egor started it.Ya ,It's all his fault,,Ya lets blame him,,Shame on you Egor __________________ NRA Certified RSO NwCP- Performance Isn't Optional

January 29, 2011, 07:33 PM	#18
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	You know how you prove that a coconut is transonic?! It'll turn you into a Gnut! (but you'll get better!) __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

January 29, 2011, 09:54 PM	#19
Ike666 Senior Member Join Date: October 10, 2009 Location: SW VA Posts: 491	buzzkill warning RANGE YARDS MUZZLE 50 100 200 300 400 500 600 1000 VELOCITY FPS 2700 2602 2504 2314 2132 1951 1778 1617 1117 VELOCITY FPS 2600 2501 2405 2219 2038 1861 1694 1536 1078 So, if I'm understanding this right, the 168 SMK Federal GMM will transition out of supersonic around 958 to 993 yards, and become inherently less stable at those ranges (give standard normal atmospheric conditions). Coconuts, however, with their substantially better BC will remain supersonic out to about 1100 yards. Yes? __________________ ___________________ "I'm your huckleberry."