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-   -   Rules of thumb (https://www.pprune.org/tech-log/340591-rules-thumb.html)

bArt2 27th August 2008 19:41

To calculate the True airspeed:

TAS = 55,1088 times squareroot T times the squareroot of the squareroot of (1+0,00023157 times IAS squared divided by P times (1+(IAS squared/1750200)))-1 :E

Or if that is to complicated, you could approximate it by using: TAS=IAS+2% per 1000'

Bart:oh:

bluelearjetdriver 27th August 2008 19:52

Quite a good one I use for time travel...E=MC^3 (that's right Einstein....cubed!!!)

plain-plane 27th August 2008 21:21

Quick Cross wind
The part of an hour…:ok:
Any thing over 60 deg off the runway: cross wind is the full wind…(a full hour)
45 deg off is ¾ hour: cross wind is ¾ the full wind.
30 deg off is ½ hour: cross wind is ½ the full wind.
20 deg off is 1/3 hour: cross wind is… well i think you get the picture… but still: 1/3 of the full wind.
nornally accurate to within 2 kts… :D

Leave 5 on the glide 27th August 2008 22:30

Tas = Ias + Fl/2

cjam 27th August 2008 23:55

The total amount of cash you'l give your current wife when she leaves in 1000's, is your average cruise TAS /2 .
This only works for wife one and two, after that divide by five.
Makes C172's look attractive.

Pilot Pete 28th August 2008 00:55

When to turn in on a visual approach from aloft downwind:

On a Boeing, be gear down flap15 (737) or 20 (75/767) passing abeam the touchdown threshold, 2 miles out abeam. Start a stopwatch and descend at idle thrust. The timing to extend downwind is;

Height above T/D threshold/100 x 1.5 and if you want to really cream it take off 1/2 the tailwind component in kts.

e.g. Pass abeam at 5000' AGL.

5000/100=50 50 x 1.5 = 75 seconds

This works well when new/training. With experience and if you want to really nail it, say with a 15kt tailwind downwind, take off about 7-8 seconds....it looks quite tight and it is, but you will stabilise on final into a 3 degree descent from above......

Take landing flap as appropriate, usually turning final. If the timing works out less than 45 seconds then make it a normal visual circuit, i.e. level off at 1500' AGL and turn in at 45 seconds (i.e. if you are passing 3000' AGL or less as you pass abeam, you are not really flying a visual approach from 'aloft', merely descending to circuit altitude before turning base/final).

Works a treat, especially at places like Pafos where you are often kept high and pass abeam at something like 8000' AGL.

PP

Permafrost_ATPL 28th August 2008 14:36

Good rule of thumb to keep you out of trouble on takeoff: the relationship between TOW and V2.

On the 737-700, the number of tons of your TOW minus 22 should be pretty close to the last two digits of your calculated V2.

e.g 55 (tons) minus 22 = 33, thus expecting V2 of 133.

Work it out for your own aircraft and fly safe...

P

TO MEMO 28th August 2008 15:24

Good one for the Sim.

both engine flameout and gliding to an airport 2 MN for each 1000 ft. And you`ll have to lower the gear around 2000ft.

Add 2500ft for an 180º turn (down wind to final). 1000ft for a 90º turn

mnttech 28th August 2008 15:51

Pounds to Gallons
 
Take Pounds times 1.5. Drop the last zero and that is the gallon amount.
Need 1000 pounds of fuel?
1000 X 1.5 = 1500
Drop the last Zero = 150 gallons of jet fuel.

Fark'n'ell 29th August 2008 09:39

flying rules
 
Hey MBSV1863.
You forget

Never take thine altitude in vain lest mother earth rise and smite thee
:)

mcdhu 29th August 2008 11:58

My Mum said to me as I went off to join the Air Force over 40 years ago:

''Always fly low and slow and use lots of top rudder in the turns.
Always keep your fingernails clean.
Never ask a lady what has been wrong with her.
Never look in a lady's handbag.''

Not bad advice really - thanks Mum.

Cheers,
mcdhu

fantom 29th August 2008 19:01

I just remembered a really important one:

"A wet owl never flies at night."

Served me well.

40&80 30th August 2008 21:39

Dear Lord..Let not my overconfidence exceed my ability.
Remember..It is the one you do not see that gets you.
Shut mouth catch no fly.
When belly touch back bone pilots talk sense.
Talk is cheap money buy land.
Never hang your basket higher than you can reach.
Check Check double check re check check.
ScanScanScan
Pitch Bank Balance Power.

capster 31st August 2008 14:05

In god we trust, the rest we check.

Always roll towards the sky pointer

misd-agin 31st August 2008 15:10

TO MEMO

Join Date: May 2007
Location: Europe
Posts: 50


Good one for the Sim.

both engine flameout and gliding to an airport 2 MN for each 1000 ft. And you`ll have to lower the gear around 2000ft.

Add 2500ft for an 180º turn (down wind to final). 1000ft for a 90º turn



Actually modern jets have glide ratios around 18:1, which equates to 3 n.m. per 1000' of altitude. 767, designed about 30 yrs ago, is 17.9:1.

TAS divided by sink rate/100 = glide ratio. Eg, 260 KTAS/1300 FPM = 20.0 (or the cheating way, 260/13 = 20)

Hmmm, have to figure out what the 757 winglet glides at.

Manuals provide the best gllide speed (L/D). Check out the "dual engine flameout" driftdown speeds. Typically (last 3 a/c I've flown) it's very close to Vref 30 + 95 kts.


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