0.72 M @ FL450 in ISA conditions in kts?

[pilot007]

Hi again,

how much is 0.72 M @ FL450 in ISA conditions in KTAS?

Don't have my good'ol FlightComputer-Slide in my pocket ;)

C ya,

pilot007

[JimmyTAP]

About 190kts IAS I reckon.

JT

[No_Speed_Restriction]

410


Disclaimer: Answer compiled using a CRP-1 and the pooley's "I havent used my CRP-1 since the last Jurassic Period"

[JimmyTAP]

About 430kts I reckon.

Or (more correctly) 413kts if local speed of sound is 573.57kts.

Alternatively 0.72 works out at 190kts CAS or 180kts EAS . root sigma is 0.44 so TAS = 180/0.44 = 409kts



JT

[BOAC]

NSR wins! Using this site (http://www.ae.su.oz.au/aero/atmos/atmtab.html) and some very rusty maths, it comes out to 413.087kts (roughly):D

This nifty little (http://www.desktopaero.com/appliedaero/appendices/stdatm.html) Javascript programme gives you the TAS in fps and we can all convert that, can't we......................:D

[A. Bruun-Pedersen]

EDIT: I just removed my answer because I answered something completely else!!!:\

[john_tullamarine]

BOAC,

Neat link.

As a long ago aero graduate of SU (in the dark ages when we were a separate Department and lived in the wonderful antiquity of PNR - did I ever tell you about the Fluid Mech exam question involving the tea lady, coffee break, and the spiral staircase .. ?) ... I have taken the liberty of linking to Doug's page on the URL sticky.

Ah ... fond .... if not always sober ... memories .. Forest Lodge bacchanalian revelries .. hours asleep in the smoking chairs in the Union Building .. the best years of one's life (for the great majority of us) were in the idyllic embrace of one's misspent undergrad days .....

[BOAC]

did I ever tell you about the Fluid Mech exam question involving the tea lady, coffee break, and the spiral staircase .. ? - careful - someone will 'Snopes' that one:D :D

Any more votes for 413.087kts (roughly)?? :p

[FlightDetent]

Surely the calculation is correct ... for TAS.

:E

FD.



[Deleted by author because he is an idiot to mistake ISA for IAS and cannot read the question in first place.]

[oxford blue]

I have to say that this all seems terribly complicated.

If I have to play this game, I can do it as well as the next man and produce complex formulae and solve them with a calculator.

I can also use a circular slide rule nav computer if I need to.

But, once above 36,090 pressure altitude (which we are) then ISA is -56.5ºC - at least, until we get to about 65000 feet.

So Mach One = 573 knots TAS (or, more practically, a bit less than 600).

So your Mach meter becomes a 'mile-a-minute meter' - ie, Mach 0.70 is 420 knots (7 miles a minute).

In the air, nobody's going to argue about 7 knots (the completely accurate answer).

[Dan Winterland]

I know some people who will!

[BOAC]

The BIG question is - did we answer 'pilot007' s' query to HIS/HER satisfaction?:D

[Old Smokey]

BOAC,

Yes, you did answer the correction correctly, I entirely concur with your answer.

The complete set of data is -

TAS = 413.1 : CAS = 191.7 : EAS = 181.7 : SAT = -56.5°C : TAT = -34.0°C.

pressman, I think you will obtain slightly improved results if you use a constant of 38.975, and -273.15°C for absolute zero.

Dan Winterland,, I also know people who would argue about a 7 Kt error, those who operate 15 hour sectors and do care about a 105 mile aggregate Air Distance error. The variable (contingency) fuel reserve for long distance operations is usually capped at 30 minutes, and that degree of error would account for about half of it.

Regards,

Old Smokey

[pilot007]

thx,

you guys rock! I'll go for fouronethree.