I've been flying FSX for several years, mainly with the default 737. I've recently purchased the PMDG 737NGX and I've got a question about something that happens in the real world vs the Sim world.

 

On approach I've noticed in real life 737-800's, the speed brakes extend intermittantly and almost like the outer speed break extends less than the inner speed break. As far as I can tell, sometimes the left side speed breaks extend when the right sides do not. It's almost like they are linked to other controls and controlled by the Autopilot.

 

In all of my Sim flying, it seems like when I deploy the speed breaks on decent and approach, they extend all at once to a fully extended position, then as I retract them, they completely retract.

 

Has anyone experienced this before ? In real world, is there a feature of the A/P that controls the speed breaks ?

 

Thanks, Lee

Alright mate,

you can control your speedbrake/spoilers, with speedbrake lever, if you don't have one (usaully comes with saitek pro throttle) you can control it via the keyboard (i think i have never tried) but sure you can deploy them half way or how you would like.

In all of my Sim flying, it seems like when I deploy the speed breaks on decent and approach, they extend all at once to a fully extended position

 

In fligh you are not allowed to move speed brake lever beyond "flight detent" position. That's why you'll never see maximum angle retraction and all spoiler panel used in-flight.

 

In real world, is there a feature of the A/P that controls the speed breaks ?

 

A/P doesn't control speed brakes. It controls ailerons. But when control wheel is turned more than 10*, flight spoilers on inner wing will extend to help ailerons to increase bank angle faster.

 

FCOM vol2 pages 9.20.5 and 9.20.17.

Yep, it's flight spoilers for roll control.

In this video notice from the :09 to :30 sec mark. This shows the partial deployement of the speedbreaks that I'm talking about.

<iframe width="560" height="315" src="http://www.youtube.com/embed/7vPbSL5NGIk?rel=0" frameborder="0" allowfullscreen></iframe>

you will notice the aileron movement and spoiler movement coincide...as previous posters have explained, roll control.

In the video which was posted above, you can also see the short field package, which lets the spoilers extend at a higher angle.

OK, thanks for the info.

 

So does the default FSX 737 or the PMDG 737NGX-800 have roll control ?

OK, thanks for the info.

 

So does the default FSX 737 or the PMDG 737NGX-800 have roll control ?

 

"roll control" isn't a system, or a thing. What they're saying is that the spoilers help bank the aircraft when the pilot turns the yoke past a certain point.

 

Also, don't judge a 737's behavior based on the default 737. There is a reason PMDG took 3 years to make this plane.

OK, thanks for the info.

 

So does the default FSX 737 or the PMDG 737NGX-800 have roll control ?

I don't know about the default one, but the ngx spoiler "roll" function works.

Just try it, turn on hyd pumps and move ailerons from 0 to full, you will see spoiler starting to rise on the wing where the aileron is going up.

The mixing function works also if spoiler are extended as speed brake, in this condition the flight panels are already extended (depending on lever position), spoilers on the side that needs to climb will go down depending on commanded angle.

Remember also that there are flight and ground spoilers, few work in air and on ground, the others only on ground.

Great information guys !!! I had never noticed it before but I will look for it now. Thanks, Lee

Great information guys !!! I had never noticed it before but I will look for it now. Thanks, Lee

 

Keep learning and have fun flying the NGX! :wink:

OK, thanks for the info.

 

So does the default FSX 737 or the PMDG 737NGX-800 have roll control ?

They both model the roll spoilers. The NGX models them much more accurately than the default 737 of course.

The roll spoiler system is 100% accurately modeled in the NGX - we had all the values and conditions for how it behaves straight from Boeing.