Q400 to the stars! (FL600+)

[KingGhidorah 209]

Perhaps if NickM is interested in comparing the Majestic's performance to the real airplane, within the normal envelope  of FL270, I found this http://cf.alpa.org/internet/alp/1999/mayQ400.htm.  It's a very detailed test flight profile with very specific numbers provided.  Here is another article with some performance numbers as well http://theflyingengineer.com/aircraft/proud-to-fly-a-turboprop-q400-vs-atr72  After reading these two articles, and looking at NickM's first post, I agree with you GHarrel, that the realistic performance within the normal operating altitudes does not seem to be compromised by this strange ability to climb north of 60,000. 

[~Craig~ 10]

[Deleted]

[Nick M 106]

Perhaps if NickM is interested in comparing the Majestic's performance to the real airplane, within the normal envelope  of FL270, I found this http://cf.alpa.org/internet/alp/1999/mayQ400.htm.  It's a very detailed test flight profile with very specific numbers provided.  Here is another article with some performance numbers as well http://theflyingengineer.com/aircraft/proud-to-fly-a-turboprop-q400-vs-atr72  After reading these two articles, and looking at NickM's first post, I agree with you GHarrel, that the realistic performance within the normal operating altitudes does not seem to be compromised by this strange ability to climb north of 60,000. 

 

Thanks for links KG - I'd seen the second one but that first article is new and I'll be sure to read it properly later.

 

For what it's worth guys, I'm definitely not suggesting that the Q400 flight model is borked within its service ceiling - just that the odd high altitude behaviour is worthy of further discussion/investigation. As per my first paragraph in this thread, I love the Q400 to bits. I've spend most of my time in her hand-flying approaches and trying to pull off respectable landings, so this high altitude stuff is a bit irrelevant I know!

 

Cheers,

Nick

 

P.S. Incidentally, I tested out the absolute ceiling of the NGX earlier today and was just about able to get a lightly loaded aircraft above FL500. However, at this point the 'coffin corner' effect was quite convincing, with the aircraft barely controllable between the stall speed and V_NE.

[~Craig~ 10]

Bear in mind one thing here .....

 

[i'm not saying this explains the entirety of this result here, but is certainly a factor] ....

 

...the reason that the Q400 is limited to a FL250 max ceiling is nothing to do with performance.   It is entirely a statutory limitation (both sides of the pond), because the aircraft has no emergency oxygen system.    There is no passenger oxygen supply in the Q400 that drops down in fancy little masks, in the event of depressurization, or any other catestrophic failure.

 

Thus the aircraft is limited to FL250, so that it is never more than 15,000' away from getting down to a safe 'unpressurized' altitude.

Look at the power to weight ratio of those powerful 5,000shp-a-side PWs, and bear in mind the fact that Q400 pilots often talk about how powerful the engines are, and that they're the best things about the aircraft.

So don't think that a Q400 should struggle to get past FL250 in a climb - not at all; a King Air can get to FL350! 

 

I am not saying a real Q400 should/would be able to make FL600 but that it should be borne in mind that the FL250 ceiling is not imposed by performance, but by legislation, on the oxygen point

 

 

REFERENCES:

 

From this article here:-

 

http://theflyingengineer.com/aircraft/proud-to-fly-a-turboprop-q400-vs-atr72/

 

.... "the Q400 can reach FL250 in 16-18 minutes"       You will not find many aircraft that reach a PERFORMANCE-based ceiling in 16 minutes.   

 

 

From this article here:-

 

http://www.flyertalk.com/forum/continental-onepass-pre-merger-closed-posting/790410-q400-aweful.html

 

"The Q400 does have oxygen masks"

[Nick M 106]

So don't think that a Q400 should struggle to get past FL250 in a climb - not at all; a King Air can get to FL350! 

 

I am not saying a real Q400 should/would be able to make FL600 but that it should be borne in mind that the FL250 ceiling is not imposed by performance, but by legislation, on the oxygen point.

 

Indeed! And I think even a type-rated Q400 pilot may find it difficult to assess how high an 'unconstrained' Q400 could climb if they were allowed to try it. (Though maybe I'm wrong on this - not sure how much the training takes in extreme situations, but I found this statement interesting in the Wikipedia Article on Pinnacle Airlines Flight 3701 which I referenced in another thread: "Pinnacle Airlines has restricted flights to a maximum of FL370. It has also changed its training program to include high altitude operations in ground school and simulator training. In addition, each crew is taken in the simulator up to FL410 and shown what the airplane did on the night Flight 3701 crashed.")

 

I suspect the question of the absolute ceiling of the real world Q400 is probably one for the designers of the real thing!

[ckyliu 1,749]

...the reason that the Q400 is limited to a FL250 max ceiling is nothing to do with performance.   It is entirely a statutory limitation (both sides of the pond), because the aircraft has no emergency oxygen system.    There is no passenger oxygen supply in the Q400 that drops down in fancy little masks, in the event of depressurization.

 

I am not saying a real Q400 should/would be able to make FL600 but that it should be borne in mind that the FL250 ceiling is not imposed by performance, but by legislation, on the oxygen point

Passenger oxygen masks are an option on the Q400, and if fitted the service ceiling increases to FL270. However, you still made a good point about the ceiling not being performance based, I suspect the FL270 is down to differential pressure structural limitations.

[~Craig~ 10]

 

http://www.flyertalk.com/forum/continental-onepass-pre-merger-closed-posting/790410-q400-aweful.html

 

"The Q400 does have oxygen masks"

 

 

Oops, that should have been typed as "The Q400 does not have oxygen masks"

 

My Typo!  :smile:

[Nick M 106]

A bit of feedback from the Developers on this topic over at the Majestic forums. Although Oleksiy's reply makes me feel a bit like a naughty boy, I can quite understand where he's coming from!

 

Needless-to-say: my enjoyment of the Q400 is undiminished and it's an add-on I won't hesitate to recommend it.

 

Will have to see what the PRO edition offers when it's finally available (the shared cockpit feature doesn't particularly interest me) but I'm certainly looking forward to seeing Majestic's implementation of the HGS.

 

Cheers,

Nick

[martin-w 3,234]

I second that, looking forward to the HGS.

 

So essentially Majestic are saying they coded the flight dynamics to perform accurately within the normal certified altitude parameters. Not necessary at altitudes that are excessive.

 

Fair enough I say, I'm happy it performs well in the normal certified regime. No point in wasting time coding that far outside the envelope.