727 Vmo?

[LEM]

What's the 727 Vmo at sea level?
I was told an amazing 450kts.
True?

[mutt]

450 Kts TRUE or INDICATED?

Mutt.

[viking737]

AA 727-200
Vmo sea level 380KIAS
21,500 ft 411KIAS

[TurbineBlade]

Hello...i have seen the 727 (aaaa what a wonderful machine !!) doing 420kts Indicated at 2000ft !! At the time aloud banging noise started at the nose area.I was new at the 27 so i was told that this sound comes from the nose gear doors banging at high speeds due to aerodynamic loads created by the fuselage !
:cool:

[LEM]

!!!!!!!!!!!!!!!!!!!!!
So you were 40 knots faster than Vmo???????????? :confused: :oh:

[HotDog]

The following from Frontier Airlines 727-191 data:

SPEED LIMITATIONS

MAXIMUM OPERATING SPEED – VMO

35,000’ - 310 KIAS .90 MACH

30,000’ - 345 KIAS .90 MACH

25,000’ - 383 KIAS .90 MACH

20,000’ - 409 KIAS

15,000’ - 403 KIAS

10,000’ - 398 KIAS

[LEM]

Thanks for the info!

ps: still wonder about the 420 KIAS.... :ooh:

[zlin77]

From memory (hazy now ), 727-200 in Australia, 360 Kias. Believe the mmo was .88. However there was a selectable function on the ASI to set a higher mmo? A feature for different airworthiness authorities who set different limits. 350 kts. to 20 nm. on descent was the "normal" high-speed descent with ATC approval.

[LEM]

However there was a selectable function on the ASI to set a higher mmo? A feature for different airworthiness authorities who set different limits.
Yeah... I started to suspect so. Interesting!
To my (very limited) knowledge, this is the only aircraft with such a feature. :suspect:

[HotDog]

I have never operated on the 727 but on the classic 747 models that were fitted with reserve fuel tanks 2 & 3, the ASIs had a NORMAL/AUX FUEL switch in the right hand bottom corner of the instrument. With fuel in the 2 & 3 reserve tanks (which had to be full if used) The ASIs were selected to the AUX Fuel position, which reduced the VMO pointer and VMO warning to a lower speed. I wonder if the discrepancies of VMO on the 727 had a similar origin of fuel tank configuration between certain models?

[LEM]

Where are those reserve fuel tanks 2 & 3 located on the Jumbo?
Is the reduction in Mmo due to wing bending limits in turbulence with the heavier weight?
Why do they have to be full if used?

Thanks for the info!

[kkbigjet]

hello all

yes u r rite ..

the diff vmo was due wing bending effect and due zero fuel limitation..this was refered to as mode A or mode B ,with a mode a aircraft having a lower zfw lt and also faster.

it was a switch which changed the barber pole on the asi as per the zfw limitation.but whats important here is that some heavier 72s were only mode B but still could to 350 kias or 0.88m.

some 72s which were capable both mode A or B as per zfw ..set mode A or B before choks off and this remained applicable throughout the flight ;implying u cud not change in the air;

i have some time on a mode A plane and have flown it 375 kias in the descent and 350 in climb .. and if i recal correct the pole was sitting at approx 390 knots.

bi bi
kunal

[747FOCAL]

I have seen flight test video of a 727 flying around somewhere just above the cascades here in Washington during flight test that was running Mach .97. She couldn't have been more than 18,000 - 20,000 ft. Although it was not cockpit instruments I was looking at on the screen. This was a documentary flight test video and the commentator said "Here we have the 727.......Mach .97 yada yada yada".

The jist is that the 727 was flight tested to that speed. I am pretty sure that in recent times the 727 and the 747 have gone Super Sonic more than any other commercial aircraft.

Who needs the Sonic Loser when you could just make a derivitave of the 727 with nice quiet efficient engines? :ok:

Wasn't the first plane into the twin towers doing like 350 kts?:(

[HotDog]

LEM, 2 & 3 reserve tanks on the classic 747 are in the wing tips outboard of reserve tanks 1 & 4.

[viking737]

My memory is getting a little fuzzy, but I think the 727-100
had a higher Vmo at sea level than the -200.
Might dig out the old books and check it.

The A-B switch on the 727-200B model I believe were
required to be in mode B at ZFW above 136,000 lbs or
TOW above 172,000 lbs. This would lower the Vmo to 350KIAS
at sea level and 372KIAS at 26,500 ft.
Mmo remained the same at Mach .90