Falcon 50 Cruising altitude >FL360?

[Gridley 257]

Hi all,

New user here, so please let me know if this is a RTFM question.

I've had a couple of flights in the Falcon50 and I'm very pleased with the aircraft - great work Flysimware!

My issue is this - I'm having a very hard time getting the plane to cruising altitudes above 36k feet.  Once above about FL310, climb rate is very slow.  I've tried mach hold as well as VS modes and I end up around 200fpm.  I have not been able to get the aircraft above FL400 at all.  I'm probably missing something with managing the engines but I'm not sure where.  I'm using P3Dv5 so I'm blind with checklists...

Any tips where I might be going wrong?

Thanks,

sg

EDIT: I have reviewed the docs in the "Reference Information" sticky...

Edited May 11, 2020 by Gridley

[Gazzareth 808]

 

The last patch reduced the power by quite a bit, not tried climbing above FL310 recent, but it used to easily cruise there at MMO, now you struggle to get to that speed at all.

 

That said always worth checking the air temperature,  if it's stupidly high it will cause you issues.

 

G

[Gridley 257]

36 minutes ago, Gazzareth said:

 

The last patch reduced the power by quite a bit, not tried climbing above FL310 recent, but it used to easily cruise there at MMO, now you struggle to get to that speed at all.

 

That said always worth checking the air temperature,  if it's stupidly high it will cause you issues.

 

G

Thanks for the reply, G.   On last flight from KMDW to KFLL, OAT was minus 30-ish, so that's probably not it.  

[Gridley 257]

As an aside - If I had been at FL420, I might have missed this! https://prepar3d.com/forum/viewtopic.php?p=217854#p217854

[Ariel 6]

AS Gazzareth said, the last change to the engine power has caused a bit of a problem.  It probably isn't possible to get it right for all parts of the flight envelope, but the the change to reduce fuel consumption at cruise levels has reduced the power available to the point where you can't get a reasonably high cruise level now.  Overspeeding is a thing of the past in level cruise, and I'm frequently flying flat out at 100% N2.  I preferred the previous high fuel consumption and more power available.

Ariel

[Gazzareth 808]

Completely agree there, was preferable to current status where it is all but impossible to get to higher cruise levels & speeds...

 

G

[Dreamflight767 312]

Is this a "bug" or real life thing?

[Mad_X 12]

On 5/13/2020 at 9:06 PM, Ariel said:

AS Gazzareth said, the last change to the engine power has caused a bit of a problem.  It probably isn't possible to get it right for all parts of the flight envelope, but the the change to reduce fuel consumption at cruise levels has reduced the power available to the point where you can't get a reasonably high cruise level now.  Overspeeding is a thing of the past in level cruise, and I'm frequently flying flat out at 100% N2.  I preferred the previous high fuel consumption and more power available.

Ariel

I disagree. I find the fuel burn to be almost spot on with real world tables and I do not like an overpowered aircraft. 

[Ariel 6]

 

 

On 5/19/2020 at 9:34 AM, Mad_X said:

I disagree. I find the fuel burn to be almost spot on with real world tables and I do not like an overpowered aircraft. 

Ok, fine, and of course it's good that the fuel burn is now more realistic.  The question is, was the general Falcon performance (climb rates, service ceiling etc) way over the top before the mod, as you imply?  Although I have time as a real-world military pilot in my younger days - I have never been in any series of Falcon, let alone the FA50 - so I'm just guessing.  But it does seem to me that it has become surprisingly sluggish above 20k, and the climb rates have dropped noticeably.  Compared to it now, the FSW Lear seems a hot ship.

Any real-world Falcon jockeys out there who can comment?  I don't have any detailed weight/temperature climb performance tables to do any worthwhile flight testing.  Do you?

Still like flying it however.  Maybe I should try going off with minimum payload and fuel and see how high I can get...

Ariel

[Gridley 257]

13 minutes ago, Ariel said:

 

 

Ok, fine, and of course it's good that the fuel burn is now more realistic.  The question is, was the general Falcon performance (climb rates, service ceiling etc) way over the top before the mod, as you imply?  Although I have time as a real-world military pilot in my younger days - I have never been in any series of Falcon, let alone the FA50 - so I'm just guessing.  But it does seem to me that it has become surprisingly sluggish above 20k, and the climb rates have dropped noticeably.  Compared to it now, the FSW Lear seems a hot ship.

Any real-world Falcon jockeys out there who can comment?  I don't have any detailed weight/temperature climb performance tables to do any worthwhile flight testing.  Do you?

Still like flying it however.  Maybe I should try going off with minimum payload and fuel and see how high I can get...

Ariel

This is what I was asking about originally - is it realistic to expect the Real World FA50 to cruise at >FL400?  SEE: https://www.aopa.org/news-and-media/all-news/2016/august/pilot/quick-look

[ark 1,290]

After seeing this thread I decided to see what would happen if I tried to reach 41,000ft with the Falcon50 (v2.0b) with moderate loading. Fuel load was about 7500lbs (half fuel), forgot to add any passengers so just had the pilot and co-pilot. Took off from my home location KCOS which is at about 6200ft and set up a full throttle IAS climb at about 180kts or so, and just let it go while I did some other things. So no step climbing, etc. As the Falcon reached 41,000 ft the IAS was down to about 155kts and the VS was about 400ft/min. The Falcon leveled off and eventually reached a cruise speed of M 0.813.

So, just one data point. Don't know how realistic this all is, although if you started out heavier I would expect you could still get up to 41,000ft by burning off fuel as needed on the way up. It would be interesting to know what a typical RW Falcon50 climb profile to 41,000ft looks like.

Jim Barrett may be able to shed some light on this.

Al

 

Edited May 20, 2020 by ark

[JRBarrett 3,070]

The aircraft may be mildly underpowered now, but it was way overpowered in the original incarnation, where one could cruise at FL390 and would have to keep N1 in the 70% range to avoid overspeeding which is very unrealistic. At cruise, N1 would  normally be above 90%

Trying to climb in IAS mode at something like 180 knots is actually very counterproductive. The nose will pitch so high to keep the speed down that drag will increase massively - a classic “back side of the power curve” scenario.

I don’t know how well it’s modeled in the sim, but the real aircraft is most efficient climbing at an IAS of at least 280 knots once above 10,000 feet. That puts the AOA in the range where the wings develop maximum lift.

You will see the same thing during climb in any well-modeled add-on with full VNAV and autothrottle, at 10,000 feet the first thing the the PMDG 737 or FSL Airbus will do is to pitch down to build up speed to at least 290-310 knots before continuing climb.

In the current FSW  model, I pitch down to acquire 320 knots climbing through 10,000 feet (using V/S), then switch to IAS hold and let it eat, controlling rate of climb with power. When current IAS reaches the point where 320 IAS = Mach 0.75, I switch to Mach hold. The transition will usually happen somewhere between FL250 and FL280, depending on air temperature. Once above FL250  or so, power levers do go almost full forward to keep a decent rate of climb.

Doing that, I have no problem reaching the mid to upper 30’s in reasonable time. I rarely fly above FL390 unless very lightly loaded, which is also true of the real aircraft. In real flights typical max cruise altitude would be FL400 westbound or FL410 eastbound. FL450 is possible, but not until the wing tanks are almost depleted, meaning you would be down to feeder fuel only, which means you had better be in a position to land within 60 minutes - i.e. once you get to FL450, you are only going to be there a short amount of time before it will be time to begin descent.

I haven’t flown on a real 50 in years, but was in the jump seat on one of our 900s just last week, and even on that aircraft, (which has TFE730-60 engines, with quite a bit more power than the 50), the power levers were pretty much full forward, and the N1 was about 98% in the climb above 30,000 feet. (The 900 does have autothrottles). 

If you have the 50 fully loaded, with full fuel and every seat filled, I would not expect a cruise altitude of much higher than FL340-350 would be possible until quite a bit of fuel has been burned.

The Lear 35 is a much lighter aircraft, and does climb faster than the 50, but on the other hand, it has far less range and payload capacity.

Edited May 20, 2020 by JRBarrett

[ark 1,290]

19 minutes ago, JRBarrett said:

The aircraft may be mildly underpowered now, but it was way overpowered in the original incarnation, where one could cruise at FL390 and would have to keep N1 in the 70% range to avoid overspeeding which is very unrealistic. At cruise, N1 would  normally be above 90%

..........

 

Jim, thanks so much for sharing your knowledge, experience and expertise. We are very fortunate to have your participation on this forum!

Al

 

Edited May 20, 2020 by ark

[JRBarrett 3,070]

42 minutes ago, ark said:

Jim, thanks so much for sharing your knowledge, experience and expertise. We are very fortunate to have your participation on this forum!

Al

 

Just want to point out I am not a commercial pilot, but as a Falcon mechanic, I do have lots of jump seat time (probably 200+ hours). I watch everything going on intently and ask lots of questions. Our company pilots are well aware of my interest in flight simulation (a couple of them are DCS fanatics themselves) and are always willing to share info on procedures. 

Speaking of the Lear, Although it has a justifiable reputation of being a “rocket ship” in climb, once in cruise, it really isn’t all that fast by modern biz jet standards. Mach 0.80-0.81 is about the fastest you would ever want to go, and pilots have to keep an eagle eye on the speed when that close to the barber pole. If it strays up to Mach 0.83, (the MMO limit), a stick puller (opposite of stick pusher) will activate which will produce a very unpleasant sudden pitch up. Mach 0.78 is a more typical (and safer) cruise speed for the Lear

The Falcon can safely cruise all day at Mach 0.84, It has a certified MMO of Mach 0.86, and that only because they had to draw the line somewhere. There is a YouTube clip from the 1980’s where Dassault test pilots took a 50 up to Mach 0.95 in a dive with absolutely no ill effect. A Lear would literally disintegrate if went that fast.

So even though the Lear would easily beat the Falcon to cruise altitude, once there, the Falcon would outrun it easily.

[ark 1,290]

14 hours ago, JRBarrett said:

Just want to point out I am not a commercial pilot, .......

Jim's being a bit modest here. Besides his impressive bizjet mechanic credentials, I have it on good authority he has RW Private Pilot experience as well.

Al