When knowledgeable people speak of a vehicle going "X Mach" they are
referencing the speed of the vehicle compared to the speed of sound at
local conditions, right?

I ask because I've heard NASA folks mentioning that the Shuttle, at some
point in it's descent, is going Mach 25. I claim that means the vehicle
is going 25 times faster than Mach at that particular pressure and temp
where the Shuttle is, while someone else claims NASA means 25 times the
sea level value of Mach, even though the Shuttle is in the very upper
atmosphere at the time.

I know to discount what reporters say, but I'm referring to engineers
and their official spokesmen.

BTW, I understand the definition of Mach references local conditions.

--
Scott
--------
It's not a coincidence that pictures that would inflame the Americans to
war are not shown extensively while those pictures that undermine our
will to fight are shown ad naseum.

In article >,
"tscottme" > writes:
> When knowledgeable people speak of a vehicle going "X Mach" they are
> referencing the speed of the vehicle compared to the speed of sound at
> local conditions, right?
>
> I ask because I've heard NASA folks mentioning that the Shuttle, at some
> point in it's descent, is going Mach 25. I claim that means the vehicle
> is going 25 times faster than Mach at that particular pressure and temp
> where the Shuttle is, while someone else claims NASA means 25 times the
> sea level value of Mach, even though the Shuttle is in the very upper
> atmosphere at the time.

Upper atmosphere conditions vary quite a bit. The upper atmosphere
absorbs quite a bit of Solar Radiation, and gets relatively warm in
the process. So - the speed associated with Mach 1 varies.
To keep things in the FLight Control System (and the Public Releations
Office) as uncomplicated as possible, but still accurate enough, NASA
uses a sylized value of 1,000 ft/sec as Mach 1 at the very high (Peak
Heating Region) altitudes. The true value for the speed of sound
wanders back and forth across 1,000 ft/sec at those heights, but not
by much.
The Speed of Sound at Sea Leve, on a Standard (29.92"Hg Pressure, 59
Deg F - 1013 mBar/15C) is about 1115 ft/sec.

So, while the number is a little bit arbitrary, it's still related to
local conditions, and not Sea Level conditions.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

thanks Peter

>NASA
>uses a sylized value of 1,000 ft/sec as Mach 1 at the very high (Peak
>Heating Region) altitudes.

This is why I stay faithful to this newsgroup despite all the insane
postings during election years. You never know when you're going to
come across some wonderful, useless bit of information like this.

I wish the people in the local cocktail circuit were more tuned in to
air & space. Then I could ambush somebody with this factoid.

Thank you, Pete!

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com
Viva Bush! blog www.vivabush.org

>>NASA uses a sylized value of 1,000 ft/sec as Mach 1 at the very high (Peak
>>Heating Region) altitudes.

>I wish the people in the local cocktail circuit were more tuned in to
>air & space. Then I could ambush somebody with this factoid.
>
>all the best -- Dan Ford

Well, Dan you just have to wait till someone says, "Boy, we've been
having some hot weather recently!"

Whereupon you respond, "Speaking of 'hot,' did you know that at the
Peak Heating Region.....

vince norris

I think that value should be 100 ft/sec. Mach one is about 600 Knots = 1
NM/Min. One NM = 6,000'. Divide 6,000 by 60 (seconds in a minute) and you
get 100, not 1,000.

--

B-58 Hustler History: http://members.cox.net/dschmidt1/
-

"vincent p. norris" > wrote in message
...
>
> >>NASA uses a sylized value of 1,000 ft/sec as Mach 1 at the very high
(Peak
> >>Heating Region) altitudes.
>
> >I wish the people in the local cocktail circuit were more tuned in to
> >air & space. Then I could ambush somebody with this factoid.
> >
> >all the best -- Dan Ford
>
> Well, Dan you just have to wait till someone says, "Boy, we've been
> having some hot weather recently!"
>
> Whereupon you respond, "Speaking of 'hot,' did you know that at the
> Peak Heating Region.....
>
> vince norris

1083 fps @ 59F, Sea Level, hypothetically dry atmosphere. STP, Standard
Temperature & Pressure. In std water, about 4800 fps. Al


"Darrell" > wrote in message
news:M7Mqc.31369$Md.30236@lakeread05...
> I think that value should be 100 ft/sec. Mach one is about 600 Knots = 1
> NM/Min. One NM = 6,000'. Divide 6,000 by 60 (seconds in a minute) and
you
> get 100, not 1,000.
>
> --
>
> B-58 Hustler History: http://members.cox.net/dschmidt1/
> -
>
> "vincent p. norris" > wrote in message
> ...
> >
> > >>NASA uses a sylized value of 1,000 ft/sec as Mach 1 at the very high
> (Peak
> > >>Heating Region) altitudes.
> >
> > >I wish the people in the local cocktail circuit were more tuned in to
> > >air & space. Then I could ambush somebody with this factoid.
> > >
> > >all the best -- Dan Ford
> >
> > Well, Dan you just have to wait till someone says, "Boy, we've been
> > having some hot weather recently!"
> >
> > Whereupon you respond, "Speaking of 'hot,' did you know that at the
> > Peak Heating Region.....
> >
> > vince norris
>
>

In message <M7Mqc.31369$Md.30236@lakeread05> - "Darrell" >
writes:
>
>I think that value should be 100 ft/sec. Mach one is about 600 Knots = 1
>NM/Min. One NM = 6,000'. Divide 6,000 by 60 (seconds in a minute) and you
>get 100, not 1,000.
>

I think you made a mistake at the very beginning:

600 knots = 600 MN/Hour = 600 NM/3600 Sec = 1/6 NM/Sec = 6000/6 ft/Sec =
= 1000 ft/Sec.

BTW, I think at sea level Mach 1 is around 660 Knots (at some "average"
temperature).

HTH,
************************************************** ****************************
* Arie Kazachin, Israel, e-mail: *
************************************************** ****************************
NOTE: before replying, leave only letters in my domain-name. Sorry, SPAM trap.
___
.__/ |
| O /
_/ /
| | I HAVE NOWHERE ELSE TO GO !!!
| |
| | |
| | /O\
| _ \_______[|(.)|]_______/
| * / \ o ++ O ++ o
| | |
| |<
\ \_)
\ |
\ |
\ |
\ |
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\ |
\ |
\_|

In article <M7Mqc.31369$Md.30236@lakeread05>,
"Darrell" > writes:
> I think that value should be 100 ft/sec. Mach one is about 600 Knots = 1
> NM/Min. One NM = 6,000'. Divide 6,000 by 60 (seconds in a minute) and you
> get 100, not 1,000.
>

Darryl, It's a good thing they had somebody behind you with the map :)

600 Kts is 10 Nautical Miles/minute, not 1.

BTW, you'd probably know this: Is theere any truth to the story that
a B-58 got itself into some manner of perdicament up over Alaska, near
one of the airbases. (For the same of Argument, I'll say Eielson, but
I don't know) The Pilot was busy trying to keep teh airplane flying,
and things were kinda touchy. While things were gyrating, the Nav
tried calling the Pilot & DSO, and for some reason (Either they were
busy trying to save the airplane, or the ICM wasn't working too well)
didn't answer. The Nav got nervous & punched out, right near one of
the Base Rescue helicopters, which scooped him up & ran for home.
In the meantime, the Pilot got things under control, & managed to get
it on the ground at this Alaskan base. As he clumb down teh ladder,
he was met by the irate Nav, who was screaming at him "Why didn't you
tell me where we were! I'm teh Navigator, dammit, and I have a right
to know!"


--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

"Al Gerharter" > wrote in message >...
> 1083 fps @ 59F, Sea Level, hypothetically dry atmosphere. STP, Standard
> Temperature & Pressure. In std water, about 4800 fps. Al
<<
<<SNIP
>For quick and dirty (in one's head) cruise calculations I always used
1.0 Mach = 600 kts. (It's closer to 610 at -57F) but that let me, for
example, say .8M was 8 miles a minute. On the deck, about 670 (11
m/min). That and using fuel flow per minute (3000pph - 50ppm) gave me
rough figures. Of course, if things looked tight, then I used the
whiz-wheel. BTW, on the deck 760 mph is close to .1M (STP), so when
your car is showing 76 mph, you're buzzing along at about .1M. (For
interstate travel, 75 mph is 12.5 miles in 10 minutes . . . we just
completed about 6000 miles of driving where I used this sort of mental
T=D/R to predict ETAs thus boggling my better half. Same sort of calcs
can be used ina light plane such as C152 . . . 6gph = 1 gal in 10 min,
90KTS = 1.5 nm/min; 120(tailwind)=2 nm/min. As above, use the
calculator if things look tight. (If they do you've screwed up.)
Walt BJ

On Wed, 19 May 2004 09:42:21 -0700, "Darrell" > wrote:

>I think that value should be 100 ft/sec.

Good thing I haven't been to any cocktail parties since the post.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com
Viva Bush! blog www.vivabush.org

Walt wrote:
>BTW, on the deck 760 mph is close to .1M (STP), so when
>your car is showing 76 mph, you're buzzing along at about .1M. (For
>interstate travel, 75 mph is 12.5 miles in 10 minutes . . . we just
>completed about 6000 miles of driving where I used this sort of mental
>T=D/R to predict ETAs thus boggling my better half. Same sort of calcs
>can be used ina light plane such as C152 . . . 6gph = 1 gal in 10 min,
>90KTS = 1.5 nm/min; 120(tailwind)=2 nm/min. As above, use the
>calculator if things look tight. (If they do you've screwed up.)

Glad I am not the only one running continuous ETAS while cruising down the
Interstate :-) Drift gets to be a bitch though!
Habit! Ingrained by instructors who are really old farts now!

Rick Clark
MFE

(OXMORON1) wrote:
>>Walt wrote:

>>BTW, on the deck 760 mph is close to .1M (STP), so when
>>your car is showing 76 mph, you're buzzing along at about .1M. (For
>>interstate travel, 75 mph is 12.5 miles in 10 minutes . . . we just
>>completed about 6000 miles of driving where I used this sort of mental
>>T=D/R to predict ETAs thus boggling my better half. Same sort of calcs
>>can be used ina light plane such as C152 . . . 6gph = 1 gal in 10 min,
>>90KTS = 1.5 nm/min; 120(tailwind)=2 nm/min. As above, use the
>>calculator if things look tight. (If they do you've screwed up.)

>Glad I am not the only one running continuous ETAS while cruising down the
>Interstate :-) Drift gets to be a bitch though!
>Habit! Ingrained by instructors who are really old farts now!

Speaking of winds and such, as an "old fart" flight instructor myself
(it's all downhill after 40, right?) here is a little homemade
question that I find many aviators both military and civil routinely
get wrong:

If you takeoff from airport "A" and fly 200 miles into a 20 mph
headwind to airport "B" at 100 mph (TAS) and then turn around and
fly back to airport "B" now with a 20 mph tailwind at the same TAS
will you complete the roundtrip flight in the same time as if you had
made the flight in no-wind conditions?

Yea or nay?

(Correct answer gets a cigar and large bucket of his favorite
drink....)

>Mike Marron > wrote:

>Speaking of winds and such, as an "old fart" flight instructor myself
>(it's all downhill after 40, right?) here is a little homemade
>question that I find many aviators both military and civil routinely
>get wrong:

>If you takeoff from airport "A" and fly 200 miles into a 20 mph
>headwind to airport "B" at 100 mph (TAS) and then turn around and
>fly back to airport "B" now with a 20 mph tailwind at the same TAS
>will you complete the roundtrip flight in the same time as if you had
>made the flight in no-wind conditions?

>Yea or nay?

>(Correct answer gets a cigar and large bucket of his favorite
>drink....)


Oops!

The above question should read, "...turn around and fly back to
airport "A" now with a 20 mph tailwind at the same TAS."

In other words, if you takeoff from airport "A" and fly 200 miles into
a 20 mph headwind to airport "B" at 100 mph (TAS) and then turn around
and fly back to airport "A" now with a 20 mph tailwind at the same TAS
will you complete the roundtrip flight in the same time as if you had
made the flight in no-wind conditions?

"Peter Stickney" > wrote in message
...
> In article <M7Mqc.31369$Md.30236@lakeread05>,
> "Darrell" > writes:
> > I think that value should be 100 ft/sec. Mach one is about 600 Knots =
1
> > NM/Min. One NM = 6,000'. Divide 6,000 by 60 (seconds in a minute) and
you
> > get 100, not 1,000.
> >
>
> Darryl, It's a good thing they had somebody behind you with the map :)
>
> 600 Kts is 10 Nautical Miles/minute, not 1.
>
> BTW, you'd probably know this: Is theere any truth to the story that
> a B-58 got itself into some manner of perdicament up over Alaska, near
> one of the airbases. (For the same of Argument, I'll say Eielson, but
> I don't know) The Pilot was busy trying to keep teh airplane flying,
> and things were kinda touchy. While things were gyrating, the Nav
> tried calling the Pilot & DSO, and for some reason (Either they were
> busy trying to save the airplane, or the ICM wasn't working too well)
> didn't answer. The Nav got nervous & punched out, right near one of
> the Base Rescue helicopters, which scooped him up & ran for home.
> In the meantime, the Pilot got things under control, & managed to get
> it on the ground at this Alaskan base. As he clumb down teh ladder,
> he was met by the irate Nav, who was screaming at him "Why didn't you
> tell me where we were! I'm teh Navigator, dammit, and I have a right
> to know!"

Whoops. Senility has hit me again. Thanks Pete. Don't know what I was
thinking of. Of course you're right. That's why I needed Herk in the Nav
seat!!!!

As for the story. I'll try to check that out next month when I go to the
B-58 Hustler reunion at Fort Worth on June 4th, 5th, & 6th. It's at the
Green Oaks Inn. Stop by and I'll buy you a beer..

Darrell

B-58 Hustler History: http://members.cox.net/dschmidt1/
-

"Arie Kazachin" > wrote in message
...
> In message <M7Mqc.31369$Md.30236@lakeread05> - "Darrell" >
> writes:
> >
> >I think that value should be 100 ft/sec. Mach one is about 600 Knots = 1
> >NM/Min. One NM = 6,000'. Divide 6,000 by 60 (seconds in a minute) and
you
> >get 100, not 1,000.
> >
>
> I think you made a mistake at the very beginning:
>
> 600 knots = 600 MN/Hour = 600 NM/3600 Sec = 1/6 NM/Sec = 6000/6 ft/Sec =
> = 1000 ft/Sec.
>
> BTW, I think at sea level Mach 1 is around 660 Knots (at some "average"
> temperature).

I fall on my sword! I screwed the pooch on that one. The 600 knot/mach 1
value worked pretty well for us in the Hustler since we couldn't go mach 1
at sea level (legally). We were limited to the most restrictive of 600 KIAS
/ Mach 2 / +115 C RAT. Although we had "momentary" limits higher.

Mike came back with:
>Oops!
>
>The above question should read, "...turn around and fly back to
>airport "A" now with a 20 mph tailwind at the same TAS."

Glad you made that correction, I was still orbiting "B"

Rick

(OXMORON1) wrote:

>Mike came back with:
>>Oops!

>>The above question should read, "...turn around and fly back to
>>airport "A" now with a 20 mph tailwind at the same TAS."

>Glad you made that correction, I was still orbiting "B"

Heh. But now that you've flown back to "A" and landed, in order to
get the cigar and bucket of your fave drink you have to hazard an
answer to the question. ;)

>Rick

No, you are exposed to the headwind for a longer time. Any wind from any
direction will increase your round trip time. Al (a very old flight
instructor)

"Mike Marron" > wrote in message
...
> >Mike Marron > wrote:
>
> >Speaking of winds and such, as an "old fart" flight instructor myself
> >(it's all downhill after 40, right?) here is a little homemade
> >question that I find many aviators both military and civil routinely
> >get wrong:
>
> >If you takeoff from airport "A" and fly 200 miles into a 20 mph
> >headwind to airport "B" at 100 mph (TAS) and then turn around and
> >fly back to airport "B" now with a 20 mph tailwind at the same TAS
> >will you complete the roundtrip flight in the same time as if you had
> >made the flight in no-wind conditions?
>
> >Yea or nay?
>
> >(Correct answer gets a cigar and large bucket of his favorite
> >drink....)
>
>
> Oops!
>
> The above question should read, "...turn around and fly back to
> airport "A" now with a 20 mph tailwind at the same TAS."
>
> In other words, if you takeoff from airport "A" and fly 200 miles into
> a 20 mph headwind to airport "B" at 100 mph (TAS) and then turn around
> and fly back to airport "A" now with a 20 mph tailwind at the same TAS
> will you complete the roundtrip flight in the same time as if you had
> made the flight in no-wind conditions?
>
>
>

Mike Marron wrote:
> Oops!
>
> The above question should read, "...turn around and fly back to
> airport "A" now with a 20 mph tailwind at the same TAS."
>
> In other words, if you takeoff from airport "A" and fly 200 miles into
> a 20 mph headwind to airport "B" at 100 mph (TAS) and then turn around
> and fly back to airport "A" now with a 20 mph tailwind at the same TAS
> will you complete the roundtrip flight in the same time as if you had
> made the flight in no-wind conditions?

Okay, I'll bite.

Looks like the no-wind solution is 4 hours, the headwind/tailwind
solution is 4.17 hours.

Just in case I win, I prefer Lagavulin 16. I'll skip the seegar.


Jeff

>"Jeff Crowell" > wrote:
>>Mike Marron wrote:

>> Oops!

>>The above question should read, "...turn around and fly back to
>>airport "A" now with a 20 mph tailwind at the same TAS."

>>In other words, if you takeoff from airport "A" and fly 200 miles into
>>a 20 mph headwind to airport "B" at 100 mph (TAS) and then turn around
>>and fly back to airport "A" now with a 20 mph tailwind at the same TAS
>>will you complete the roundtrip flight in the same time as if you had
>>made the flight in no-wind conditions?

>Okay, I'll bite.

>Looks like the no-wind solution is 4 hours, the headwind/tailwind
>solution is 4.17 hours.

>Just in case I win, I prefer Lagavulin 16. I'll skip the seegar.

Al Gerharter was the first to answer correctly, but disqualified
himself by admitting that he's an old hand instructor so it looks
like you won indeed. Congratulations! A large bucket of Lagavulin
16 is on the way...

>>
>> In other words, if you takeoff from airport "A" and fly 200 miles into
>> a 20 mph headwind to airport "B" at 100 mph (TAS) and then turn around
>> and fly back to airport "A" now with a 20 mph tailwind at the same TAS
>> will you complete the roundtrip flight in the same time as if you had
>> made the flight in no-wind conditions?
>
>Okay, I'll bite.
>
>Looks like the no-wind solution is 4 hours, the headwind/tailwind
>solution is 4.17 hours.
>

Because you spend more time going against the wind and fighting it, than you
spend with the wind and benefitting from it, so thats why you lose time




Ron
Tanker 65, C-54E (DC-4)
Silver City Tanker Base

(Ron) wrote:

>Because you spend more time going against the wind and fighting it, than you
>spend with the wind and benefitting from it, so thats why you lose time

Amazing how many folks fail to grasp this concept.

Instead of forever battling headwinds, one of these days I'm going
to get in and burn an entire tank of gas or two while intentionally
flying WITH the wind and see where the tailwinds take me....

"Mike Marron" > wrote in message
...
> (OXMORON1) wrote:
> >>Walt wrote:
>
> >>BTW, on the deck 760 mph is close to .1M (STP), so when
> >>your car is showing 76 mph, you're buzzing along at about .1M. (For
> >>interstate travel, 75 mph is 12.5 miles in 10 minutes . . . we just
> >>completed about 6000 miles of driving where I used this sort of mental
> >>T=D/R to predict ETAs thus boggling my better half. Same sort of calcs
> >>can be used ina light plane such as C152 . . . 6gph = 1 gal in 10 min,
> >>90KTS = 1.5 nm/min; 120(tailwind)=2 nm/min. As above, use the
> >>calculator if things look tight. (If they do you've screwed up.)
>
> >Glad I am not the only one running continuous ETAS while cruising down
the
> >Interstate :-) Drift gets to be a bitch though!
> >Habit! Ingrained by instructors who are really old farts now!
>
> Speaking of winds and such, as an "old fart" flight instructor myself
> (it's all downhill after 40, right?) here is a little homemade
> question that I find many aviators both military and civil routinely
> get wrong:
>
> If you takeoff from airport "A" and fly 200 miles into a 20 mph
> headwind to airport "B" at 100 mph (TAS) and then turn around and
> fly back to airport "B" now with a 20 mph tailwind at the same TAS
> will you complete the roundtrip flight in the same time as if you had
> made the flight in no-wind conditions?
>
> Yea or nay?
>
> (Correct answer gets a cigar and large bucket of his favorite
> drink....)

No.
Pepsi please.

On Sat, 15 May 2004 21:25:59 -0500, "tscottme" >
wrote:

> I ask because I've heard NASA folks mentioning that the Shuttle, at some
> point in it's descent, is going Mach 25. I claim that means the vehicle
> is going 25 times faster than Mach at that particular pressure and temp
> where the Shuttle is, while someone else claims NASA means 25 times the
> sea level value of Mach, even though the Shuttle is in the very upper
> atmosphere at the time.



It's a definition thing. The Orbiter goes Mach 25, by definition,
until the dynamic pressure gets high enough to be sensed, which is at
(surprise!) Mach 25. If you use the real dynamic pressure, which is
zero, the Mach number goes to infinity, so we set it to Mach 25 by
definition to avoid that.

It isn't sea level Mach number for that airspeed. No one uses
"equivalent Mach number". That's because the aerodynamics and
aerothermodynamics are functions of Mach number, so it has to be
local.

This means you're right and someone else is wrong.

Perhaps that someone else is confused by equivalent airspeed, usually
presented by PAO as miles per hour. That is the sea-level airspeed
that the airplane would have to fly at to have the same Mach number at
sea level that it has at altitude.

I don't have my calculator or my standard atmosphere here, so the
numbers I'm about to give you will be only approximate. Flying Mach 3
at 80,000 ft is an indicated airspeed of about 300 knots (300 KIAS).
At sea level, the equivalent airspeed would be about 3,000 fps, which
you'll have to convert to knots (this will be KEAS).
[i]
> I know to discount what reporters say, but I'm referring to engineers
> and their official spokesmen.

You can check this in "Space Shuttle Hypersonic Aerodynamic and
Aerothermodynamic Flight Research and the Comparison to Ground Test
Results", Kenneth W. Iliff and Mary F. Shafer, NASA-TM-4499, June,
1993. If you go to http://www.dfrc.nasa.gov/DTRS/1993/Bib/H-1894.html
there's a link to a pdf version.

One of the early references explains the air data system, including
this Mach number definition.

Mary

--
Mary Shafer Retired aerospace research engineer

On Sun, 06 Jun 2004 20:42:51 -0700, Mary Shafer >
wrote:

>At sea level, the equivalent airspeed would be about 3,000 fps, which
>you'll have to convert to knots (this will be KEAS).

I make 3,000 fps to be 2.758 knots....


all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com

"Cub Driver" > wrote in message
...
> On Sun, 06 Jun 2004 20:42:51 -0700, Mary Shafer >
> wrote:
>
> >At sea level, the equivalent airspeed would be about 3,000 fps, which
> >you'll have to convert to knots (this will be KEAS).
>
> I make 3,000 fps to be 2.758 knots....

Did I miss something, like a really strange joke or
that you're calculating some (correction?) factor at
3000 fps and want the answer in knots?
Did you really determine 3000 feet per second to
be less than 3 knots? Knots as in nautical miles per hour?
Or perhaps it was a type and you meant 2758 knots?
2578 knots would still be way off, but it would at least
be of the right magnitude;
3000 fps = 2045.4545... mph ~= 1777 1/2 knots.

Got to be the correction factor...

Perhaps my calculator left off some zeros.

On Tue, 8 Jun 2004 03:17:26 -0400, "John Keeney" >
wrote:

>
>"Cub Driver" > wrote in message
...
>> On Sun, 06 Jun 2004 20:42:51 -0700, Mary Shafer >
>> wrote:
>>
>> >At sea level, the equivalent airspeed would be about 3,000 fps, which
>> >you'll have to convert to knots (this will be KEAS).
>>
>> I make 3,000 fps to be 2.758 knots....
>
>Did I miss something, like a really strange joke or
>that you're calculating some (correction?) factor at
>3000 fps and want the answer in knots?
>Did you really determine 3000 feet per second to
>be less than 3 knots? Knots as in nautical miles per hour?
>Or perhaps it was a type and you meant 2758 knots?
>2578 knots would still be way off, but it would at least
>be of the right magnitude;
>3000 fps = 2045.4545... mph ~= 1777 1/2 knots.
>
>Got to be the correction factor...
>

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
The Piper Cub Forum www.pipercubforum.com