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-   -   Cruise Mach for various Business Jets (https://www.pprune.org/biz-jets-ag-flying-ga-etc/527567-cruise-mach-various-business-jets.html)

WeekendFlyer 11th Nov 2013 16:25

Cruise Mach for various Business Jets
 
All,

I was wondering if you could provide me with the cruise mach number and Mmo for the various business jet types that you fly? I understand that some of them are quite a lot faster than typical commercial jets and I want to get an idea of the speed difference. It is for a project I am working on, to correlate high cruise speed with specific design features (e.g. wing sweep, thickness to chord ratio, aerofoil section, etc).

Grateful for any help you can provide.

Regards,

WF

marianoberna 11th Nov 2013 16:32

My Cessna 150 cruises at mach 0.12 at 8000 feet :}:}:}:}:}:}:}

Gulfstreamaviator 11th Nov 2013 17:13

is that with the forward galley
 
it does make a difference, of 0.00001, and speed is important.

glf

tin hat at the ready

falconeasydriver 11th Nov 2013 17:23

The falcon I used to fly told you it was doing .82, but was really only doing .81
The G550 I flew was happy at .83
The 777 I now fly is happy at .83-85.

Dash8driver1312 11th Nov 2013 17:52

Cruise Mach for various Business Jets
 
We're straining our PeeDubs trying to drag our wings up to M0.6 on the Mighty Q400!

dirk85 11th Nov 2013 18:49

Citation Excel/XLS as close as possible to the MMO without triggering the overspeed warning, ie about .73/.74.

Globally Challenged 11th Nov 2013 19:25

Challenger 300
 
Cruise 0.82 (unless you are trying to eek out 7 hours across the atlantic with a jet stream in the face - in which case it was 0.80 today)
MMO 0.83

Astra SPx 11th Nov 2013 19:48

Astra SpX/Gulfstream 100
 
Cruise Mach usually between 0.82 - 0.83, have seen 0.85.
Mmo 0.875

His dudeness 11th Nov 2013 19:53

C680 MMO .8 max speed varies a lot with altitude and weight. Usually doing HSC at .74 to .8

The ones much faster are few, the G650 and Citation 10/X spring to mind.

fleigle 11th Nov 2013 19:56

Citation X could do .92 but normally .88-.89 for "economy"
f

Pratt X 3 11th Nov 2013 20:47

Challenger 604/605 & Gulfstream G200
 
CL604/605
Mmo 0.85
Normal cruise 0.80 (large decrease in fuel efficiency above that speed)
Most efficient speed 0.77-0.78
LRC 0.74

G200
Mmo 0.85
Normal cruise 0.81-0.82
LRC 0.74-0.75

Deep and fast 11th Nov 2013 22:25

Embraer legacy M0.78

No the fastest but has a huge cargo hold for a biz jet

D and F

Jet Jockey A4 12th Nov 2013 01:39

Cruise speed...
 
For the Global 5000 and XRS the speeds are as follows...

Keep in mind that maximum TAS and Mach vary with altitude/temperature and the higher you go the lower the MMO will be.

VMO (SL - 8000') = 300 KIAS

VMO (8000' - 30,267') = 340 KIAS

MMO (30,267' - 35,000') = 0.89M

MMO (41,400') = 0.88M

MMO (47,000') = 0.858M

MMO (51,000') = 0.842M

Normal cruise speed is 0.85M and we use for long range cruise speed when heavy 0.82M.

If you really want to go fast and fly as close to the VMO/MMO you would fly the Global between 30,000' and 41,000'.

Trim Stab 12th Nov 2013 07:14


VMO (SL - 8000') = 300 KIAS

VMO (8000' - 30,267') = 340 KIAS
Is that a step-change at 8000'? Must be a right PITA in the descent! The CJ2 has a similar step-change at about 6000' IIRC and it was always a challenge to remember to slow down enough to stop the overspeed klaxon sounding.

His dudeness 12th Nov 2013 07:30

That change is also at 8000ft (something to do with windshield certification) - I think every Citation has it....

For the Sovereign that is 270/305

south coast 12th Nov 2013 07:43

DA7X

High speed 0.85
LRC 0.8
MMO 0.9

Jet Jockey A4 12th Nov 2013 10:57

In reply to trim stab...
 
Quote...

"Is that a step-change at 8000'? Must be a right PITA in the descent! The CJ2 has a similar step-change at about 6000' IIRC and it was always a challenge to remember to slow down enough to stop the overspeed klaxon sounding."

I don't see how it is a problem seeing that you have to be at 250 kts below 10,000' in most if not all airspaces in the world.

First.officer 12th Nov 2013 11:29


I don't see how it is a problem seeing that you have to be at 250 kts below 10,000' in most if not all airspaces in the world.
Not in the London TMA if they give you free speed....:eek:

Quite happily get 270kts in the CJ2+ - as said, you get to 8000ft, and then VMO drops to around 263kts IAS, and if you forget that (as previously mentioned), you do get a nice alarm in your earholes hehe - you only forget once or twice after that ;-)

Oh, CJ2+ MMO I think is M0.737, usually with a good ISA and FL450 Cruise, you can expect say M0.71...

F/o

Jet Jockey A4 12th Nov 2013 11:39

In reply to First.officer...
 
Quote...

"Not in the London TMA if they give you free speed...."


I did say "most" airspaces in the world... Too bad Canada changed their speed restrictions to align themselves with "the rest of the world" some years back.

It used to be that on departure in Canada if you were cleared above 10,000' one could accelerate to any speed above 250 knots while in the climb. )-:

ksjc 12th Nov 2013 16:15

@AstraSPx

Are you sure about your cruise speed and MMO?

I spent 13 years in the IAI 1125 ASTRA and it was a 0.78 cruiser with 0.835 MMO. Is the SPx different?

Also, regarding GLEX speeds...

A quiet flight deck to be sure but anything above 320 KIAS gets unbearably loud up front. Don't know why one would want to fly faster. You are only in this realm in the teens during descent anyway.

WeekendFlyer 12th Nov 2013 17:12

All, thanks for replies so far, very useful. Just wondered if there are any G650 pilots who would be willing to add to the discussion?

A Pandy 12th Nov 2013 19:14

Cruise Speeds
 
I fly the G650.
The MMO is .925. Normal cruise is .90 with long range cruise between .85 and .87.
For flights under 5000nm we will normally plan .89 as this seems to be far more fuel efficient than pushing up the power to .90.
For legs over 5000nm we will normally plan at .85 or .87 mach. Speeds below .85 do not benefit much due to the drag curve.

SCSflIer 13th Nov 2013 00:58

Cruise speeds
 
DA2000

MMO-.865
Intermediate- .75
LRC- dependent on temp/ ALT. In the ball park of .72
Normal cruise .80, seems to be the best of both worlds. (Speed/Efficiency)

SCSflIer 13th Nov 2013 01:03

Cruise speeds
 
HS-125 (800XP)

MMO- .80
Normal cruise- .74-76
LRC- .72

And for 700 series, you are lucky for .70 on a good day!

WTON 13th Nov 2013 04:53

HS 125 Hawker XP series:

MMO .80

Long range .70
Normal cruise speed .76

@ FL410

Astra SPx 13th Nov 2013 06:04


I spent 13 years in the IAI 1125 ASTRA and it was a 0.78 cruiser with 0.835 MMO. Is the SPx different?
Absolutely. It's a completely different bird.

From the QRH, max cruise:

FL450, ISA, 17000 lbs, 0.81, ISA - 10 gives 0.835, ISA + 10 gives 0.717
FL370, ISA, 24000 lbs, 0.825
FL390, ISA, 16000 lbs, 0.839
FL410, ISA, 18000 lbs, 0.83, ISA - 10 gives 0.847

Mmo 0.875
Vmo 353 KTS
High speed climb is 0.72

epsum 13th Nov 2013 11:18

Lear 60,
MMo M.81 (up to F380-390)

Normal cruise .77-.78 (@F400/410)
Long range .72

Booglebox 13th Nov 2013 22:17

Here's one: Cessna C525 CitationJet ("CJ0" as we like to call it) - M0.62 :}

stilton 16th Nov 2013 05:24

The G650 is pretty impressive.


Just wondered why Gulfstream didn't give it slats and / or more range ?

Welle 16th Nov 2013 07:58

GL5T
 
GLEX - normally cruising 0,83- 0,85
LR cruise - 0,80-0,83

welle

formulaben 16th Nov 2013 08:03


That change is also at 8000ft (something to do with windshield certification) - I think every Citation has it....
Bird strike protection.


§25.631 Bird strike damage.

FAA
The empennage structure must be designed to assure capability of continued safe flight and landing of the airplane after impact with an 8-pound bird when the velocity of the airplane (relative to the bird along the airplane's flight path) is equal to VC at sea level, selected under §25.335(a). Compliance with this section by provision of redundant structure and protected location of control system elements or protective devices such as splitter plates or energy absorbing material is acceptable. Where compliance is shown by analysis, tests, or both, use of data on airplanes having similar structural design is acceptable.

EASA
The aeroplane (all structure, including windshield) must be designed to assure capability of continued safe flight and landing of the aeroplane after impact with a 4 lb bird when the velocity of the aeroplane (relative to the bird along the aeroplane’s flightpath) is equal to VC at sea-level or 0.85 VC at 2438 m (8000 ft), whichever is the more critical. Compliance may be shown by analysis only when based on tests carried out on sufficiently representative structures of similar design. (See AMC 25.631.)


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