[LOGGED 2435] Engine failure just above V1 - Not enough rudder

[richjb]

Greetings...

First, my compliments on the most complete simulator that I have seen since I first starting using flight simulators from the Sublogic days.  I've been corporate aviation for 35 years, and for last 12 I have been flying the Challenger 300 and 350.  I've never seen anything like this a flight sim product (X-Plane, FSX, P3D, PS1/PSX, take your pick).  I am approaching this airplane as if I am in my first week of ground schools at FSI or CAE.  Kudos on that! 

I have done some flying with it, and one my first tests was to perform a V1 cut.  I did it fairly light weight 34K and 38K, standard day, no wind, 1000' PA.  V1 speed was 115 KIAS and the engine failure was set to 117 KIAS.  With the aircraft on the ground, at the point of engine failure (L Engine Permanent Flameout), the nose yawed just a bit and it did not take a lot of rudder to keep it straight.   At VR, I rotated toward the command bar attitude.  When she broke ground, the amount of rudder required drastically increased.  An increase in rudder is expected leaving the ground, but it was probably excessive from my experience in similar jets in the Level D simulator and even a few V1 cuts in the actual airplane during training.   

What I noticed most of all was that climbing at V2 speed, which was 133 KIAS, I could not apply enough rudder to center the turn slip indicator, i.e., "the dog house".  The best that I could do was a half brick out towards the operating engine.  Naturally, there was noticeable left yaw and left heading change that could not be counteracted.  In short, the airplane did not have enough rudder authority. 

For controls, I have a fairly decent rig.  I have a PFC Jetliner yoke and the old FlightLink rudders, which are fairly sturdy.  In X-Plane, I tried setting the response curve to linear, I set the both stability augmentation and control response to "0", which as I understand should give me full control response. 

Has anyone else tried a V1 cut?  If so, what has been your experience?  It might be that I have controller issue. 

During testing, was rudder authority checked for a V1 cut?   Were there any issues?  Anything I need to set in the controller setting to improve performance or correct this problem? 

Really enjoying the Hot Start CL650! 

Thanks!

Rich Boll

 

  

 

[Graeme_77]

Hello Rich,

V1 cuts were tested during the development phase, and rudder authority increased to make it workable, but it is possible some further refinement is needed.

The support volunteers vary in experience, from PPL, Airbus, CRJ and Gulfstream pilots, and there are experienced Challenger pilots and Challenger subject matter experts who also know their way around X-Plane well.

As an Airbus driver I do find the Challenger hard work on one engine in X-Plane, partly because the Airbus is blessed with a massively powerful rudder and trim, and also because I have pretty cheap rudder pedals and typically fly twist stick rudder.

I've asked one of the Challenger pilots to have a look at your report and provide feedback. Should changes be required the developers will do the very best they can, as the objective is to make this simulation as close to perfect as the technology allows.

The standard disclaimer about a recreational product, not for real training, etc, etc.

Thanks for a detailed write-up, and it's great that the simulation appeals equally to enthusiasts and professional pilots.

 

[Graeme_77]

Just to keep you updated Rich, one of the Challenger 650 pilots has reviewed the flight performance and checked your report, and agrees that some more refinement is possible. I've logged the case for the developers, and this thread will be updated when I've got more information. Thanks again for the detailed report.

[richjb]

Thanks Graeme!

I haven't had the privilege of flying the CL650.  I flew the old 600 with Lycoming's way back in 1988, but can't remember squat other than it really few nice!   I was much disappointed by the fact that the CL300/CL350 did not fly as nice.  That said, the rudder on the CL300 is pretty good and a V1 cut even at light weight, close to VMCG is fairly easy to handle.  In most cases, full rudder is not even required.  The CL350 is another matter.  The extra engine thrust pretty much means go to the stop on a V1 cut. 

My FlightLink rudders are getting old, and FlightLInk is out of business.  Too bad, they were a good company.  I have noticed that with right rudder, which I would have been using with a Left engine flameout, does not register to full authority in the X-Plane joystick response curve. Even with the stability augmentation and control response sliders full left, the right rudder at full deflection only goes up to 0.7 or so on the vertical "Y" axis.  I have tried everything short of uninstalling and reinstalling.  I figure I'll wait for XP12 for that!

Thanks again for your help!

Rich Boll