739NG too heavy?

Quote from Phil747

okay so i appreciate that weight and balance is a big thing to implement, but that means that every aircraft is programmed to handle a certain way. yesterday i took the new 737 out, 33,000 feet, in the CRZ thrust limit, and while it did take a lot longer to climb, it seemed happy at altitude. no idea if i'm doing something wrong, but at flight level 350, 267 knots indicated (M.785) in the CRZ thrust detent, the speed just gradually creeps back, like it's too heavy to sustain flight at altitude. have to leave it in CLB 1 to keep my speed or else it will eventually stall out. same for the 747; anything over 35 or 36,000 it seems too heavy to be able to cope with the altitude. 35,000 shouldnt be a big ask for the 739 but it seems with this one that it is. is it because i upped the V/S just beforehand just to get it to climb quicker and didnt climb slower like i did before?

what kind of altitudes and speeds do you guys cruise at with it? do you ever touch the thrust limits once it's in cruise or leave it in CLB, CLB 1, etc

Edit: the autobrakes on the 739 dont seem to automatically disable from RTO after takeoff as well unlike every other Boeing in the sim

This allegation is unfounded. I just took a flight on the Boeing 737-900ER and everything went smoothly without any problems. You are probably making mistakes when piloting the aircraft. There's nothing wrong with the plane. There is no bug that could compromise the flight on the 737-900ER.

Quote from Phil747

1) yes youre 98% right i still dont know what the hell im doing with the new 737

2) i got a dev response already, your entire post there was totally unnecessary. i see your overprotective attitude towards the sim still hasn't gone yet.

edit: get up to 35,000, set 267 knots indicated on the MCP, then stick it in the CRZ thrust/N1 limit and tell me if the airspeed starts bleeding back.

I defend what is right. As I mentioned in the previous answer I did a complete flight on the 737-900ER and didn't encounter any bugs. I support the sim because I see that the developers' work is great. Of course, there is nothing perfect in this life and there are flaws. Despite this, the simulator will be better worked on over the months as guaranteed by the developers.

Take a look at video tutorials, it could even be from PMDG to help, as I think it's your mistake, this doesn't happen here

The outside air temperature and tropopause might not be modelled world wide or even at all but above 30,000 feet in Aerofly observing the Mach limit in the climb will appropriately result in a rapidly reducing indicated airspeed so keep an eye on it but follow Mach No.

If a Mach No. hold in the climb is not possible try a carefully monitored vertical speed mode and creep up very slowly continuously reducing the rate to maintain Mach No whilst keeping the engines from overspeeding.

‘Reverse engineering’ the high altitude performance in Aerofly generates a remarkable specimen atmosphere miles away from the nominal International Standard Atmosphere.

Does anyone else feel the 737 is too “weak”? When taking off, I need to use 90%+ thrust with 5 degrees flaps to maintain a positive speed when using a 15 degree takeoff angle

Quote from Phil747

Might be worth it. Taking the 78X from Chicago to São Paulo then probably an AF77W back to Paris, so won’t touch the 739 for a while. Good to use the time to actually learn what altitudes this thing can cruise at without stalling out 😂

(Can it reach FL370 or 380 and not stall out in the CRZ flight detent?)

Today I was testing it, and it only remains at high altitudes practically with the throttle in TO/GA, I tested different retentions and only 99% and 103% made it remain stable in cruise

Quote from aviation2023 BR

Today I was testing it, and it only remains at high altitudes practically with the throttle in TO/GA, I tested different retentions and only 99% and 103% made it remain stable in cruise

Same for me

Look at the fuel flow at high altitude. The maximum rpms only just generate sufficient air density in the combustion chambers to sustain the flame. The thrust produced is very modest and the plane can be quite close to its stall indicated airspeed despite the high Mach No. and high true airspeed through the cold very thin air. The old 707 could be routinely operating in the coffin corner, at a height where it was only a fraction above its stall and hard up against its Mach limit, unable to either slow or speed up.

Running in what can be 75% vacuum relative to sea level, the flat out engines drive the generators, feed the air conditioning packs and only what is left propels the plane. The reason step climbs are well into the flight and gain only a modest level increase is that significant fuel weight must be burned off to have any extra performance margin.

Selecting power and climb rates manually in the sim might be more rewarding and more fun.

Quote from Phil747

i let the aeroplane climb up to about 20/23 or 24,000 feet (while still having a target of 33,000 set in the MCP) and engaged the CRZ thrust limit.... Activating CRZ above 30,000 is still fine as long as the vertical speed is lowered

Why on earth do you select CRZ limit while still climbing and especially at such low altitudes?

You should always climb with the CLB limit selected.

I don't know what the simulated weight of the Aerofly 737 is, but e.g. the A320 IRL struggles with anything above FL300 at high weight.

Check the pitch attitude during cruise. If it's higher than 2-2.5deg you are simply too heavy for this FL.

My airplane art:

Bernt Stolle - Art for Sale | Fine Art America

Quote from Phil747

okay so i appreciate that weight and balance is a big thing to implement, but that means that every aircraft is programmed to handle a certain way. yesterday i took the new 737 out, 33,000 feet, in the CRZ thrust limit, and while it did take a lot longer to climb, it seemed happy at altitude. no idea if i'm doing something wrong, but at flight level 350, 267 knots indicated (M.785) in the CRZ thrust detent, the speed just gradually creeps back, like it's too heavy to sustain flight at altitude. have to leave it in CLB 1 to keep my speed or else it will eventually stall out. same for the 747; anything over 35 or 36,000 it seems too heavy to be able to cope with the altitude. 35,000 shouldnt be a big ask for the 739 but it seems with this one that it is. is it because i upped the V/S just beforehand just to get it to climb quicker and didnt climb slower like i did before?

what kind of altitudes and speeds do you guys cruise at with it? do you ever touch the thrust limits once it's in cruise or leave it in CLB, CLB 1, etc

Edit: the autobrakes on the 739 dont seem to automatically disable from RTO after takeoff as well unlike every other Boeing in the sim

The FMC thrust limit page displayed after climbing above the thrust reduction height gives three options, GA, CON and CRZ. For full engine output climb the CON option provides the Maximum Continuous Thrust Limit, this will get you to the highest performance altitudes. GA gives a higher Go Around climb thrust limit.

Quote from Phil747

(Can it reach FL370 or 380 and not stall out in the CRZ flight detent?)

No. That's one of the major shortcomings of Aerofly. Since the planes don't use any fuel, you can't do step climbs to higher FLs because the weight doesn't change.

My airplane art:

Bernt Stolle - Art for Sale | Fine Art America

You get to less than 100 feet per minute climb in the Aerofly 737-900 at 39,600 feet at Mach 0.78. The angle of attack is 4.1 degrees, higher or lower attitude and you lose height, do a turn and you lose speed and or height and you cannot get it back. You have to drop several hundred feet to get a tiny performance margin to recover and very slowly creep up again.
(Manual throttles at 100% N1, they can go higher. The 100 feet per minute climb rate is at the Service Ceiling, the point to sensibly give up).