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ramprat

Not getting full power out of the Navajo.

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Hi all,

 

I noticed this Navajo seemed underpowered from what I remember.  I found the problem.  The manifold pressure should be about 46" at full throttle.  This Navajo was only getting 40".  At first I thought it was a hardware problem, but it turned out to be an incorrect setting in the aircraft config file.  You can fix it by opening the aircraft config file and find [piston_engine].  Under that catagory find max_design_mp=40.  Change it to max_design_mp= 46 and save the file.

 

It will make the airplane behave more like the real deal.

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Bill,

 

I agree. I found the same thing and had set my max_design_mp to 45. Good call.

 

Greg

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Curous what doesn't work in this plane.  It's my pet peeve that a lot of switches are stubbed out on Carenado planes.  Also, I don't see the typical bugs thread on her.  So far I've heard:

 

  • Underpowered
  • Landing lights weak.  Internal lights need work.
  • No sound change between 30-40 MP.
  • Wrong autopilot.
  • AI a little off

That's a pretty short list for Carenado, if that's it.  It would be a good sign if they took the bug list seriously and fixed them.

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Add to the list:

  • Flap deflection on the first detent is too far down.  Should be closer to a trail setting (about 10 degrees).  Second detent should be about 20 degrees.
  • The shaking effect on start up and shut down is excessive.

And, it would be nice if they used the GTN750 panel insert that include the click spot for the pop-up.  But, I agree, this is a pretty short list.


Bill,

 

I agree. I found the same thing and had set my max_design_mp to 45. Good call.

 

Greg

Good call back at ya Greg.  We both noticed the same thing.

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Flap deflection on the first detent is too far down.  Should be closer to a trail setting (about 10 degrees).  Second detent should be about 20 degrees.

 

Fixable in the config?  Might throw off the FDE though.

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I don't know if we can fix it or not.  I mess with it and report back if I can find a fix.  My ability with all this is limited.  I call it the monkey method.  That's based upon the Scopes Trial ie; If you pound on the key board long enough......

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How many notches of flaps are there?  Found this in a PIM...

 

EDIT: Never mind...found it.  You are correct.  Notch1: 10, Notch 2: 20, Notch 3: full.

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it would be nice if they used the GTN750 panel insert that include the click spot for the pop-up

 

You might try clicking on the thin edge at the top of the GTN750's bezel - this is where the click-spot is in the 404 - of course the "Home" button shows the "D->" label, but hey, you can't have everything I guess. :P

 

Note: you click on the left side of the bezel as per normal to put the 750 back in the dash, go figure...

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Gregg,

 

I found correcting the max_design_MP to 45 also fixes the sound issue as well as the power issue. You can hear the difference when you pull the MP and RPM back.

 

Greg

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Also, I don't see the typical bugs thread on her.

 

Or it could be a possible sign that less people have purchased this plane based on past experiences.  Thus, less bugs reported due to less people flying this model.

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I just submitted this to Carenado Support.  We shall see what happens.

 

Hi,

I used to fly the Navajo years ago when I worked for the Piper Dealer in Sacramento, California.  
So, I was excited to see your product.  I bought it and I think it has real potential to be one of your best.  However there are a few areas that need attention that would make it closer to the real deal IMO.

1.  Maximum manifold pressure should be 46" instead of 40".
2. Lighting needs attention both inside and outside (Landing Lights, Stobes, Instument Lights)
3. No engine sound change when reducing power until approximately 32" of MAP.
4. The airplane really needs a three axis autopilot.  I never saw a Navajo with a two-axis autopilot.
5.  Flap deflection on the first detent is too far down.  Should be closer to a trail setting (about 10 degrees).  Second detent should be about 20 degrees.  The third detent should be about 30 degrees.  
6.  The shaking during startup and shut down is way too strong.  There really shouldn't be any perceivable shaking if the airplane is in good condition.
7.  I am using the GTN750.  I would like to see the GTN750 bezel with the click spot for a pop-up.

Thank you!


 


You might try clicking on the thin edge at the top of the GTN750's bezel - this is where the click-spot is in the 404 - of course the "Home" button shows the "D->" label, but hey, you can't have everything I guess. :P

 

Note: you click on the left side of the bezel as per normal to put the 750 back in the dash, go figure...

Well I'll be a blue nosed gofer.  I never would have thought of that.  It works, thanks.

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What does 2-axis autopilot mean? I assumed that it would mean roll (aileron) and pitch (elevator). Yet the autopilot coordinates rudder in turns beautifully, so I think the "autopilot bug" is about a label on a texture, is it not?

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Hi Jim.

 

You are correct. The axis designation for an autopilot does refer to the number of axes about which an airplane rotates when a contol imput is applied.  The three axis autopilot does add contol over the yaw axis (rudder).  However, it is usually more of a yaw damper than a turn cooridinator in my experience as the aileron yaw induced by an autopilot is minimal in most cases.  Every three-axis autopilot I ever saw added a degree of sophistication that allowed the pilot to pre-select an altitude for climb and descent.  That altitude pre-select feature is what I am looking for in this Navajo.  I should have stated it that way. 

 

 

PS:  I just modified my request to Carenado Support accordingly.  Thanks for pointing this out.

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Understood, I guess I wouldn't have expected an altitude pre-set in an aircraft like this so I assumed it was modeled correctly, or at least typically. It would be nice to have.

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There may have been some Navajo aircraft with a two-axis autopilot, but I never saw one.  I hear there were also some early versions of the Navajo with normally aspirated engines.  I never saw one of those either.  So, who knows, maybe I'm wrong in assuming most were equipped with three-axis autopilots.  However, all the Aztecs,Twin Comaches, 310's, 400 series Cessnas etc I saw back then also had three-axis autopilots as I recall.  As I have been thinking about it, the two-axis autopilots I saw were always in single engine aircraft.  I don't remember ever seeing one in a twin.  But what I recall is really not important.  I just hope Carenado will patch the Navajo and address the bugs that have been reported by me and others who have some experience with the airplane.  

 

Cheers,

 

Bill   

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I have submitted my bug report via a ticket based on my findings (which largely match what has been written here) and based on points I haven't seen yet but which have been reported in this thread. I urge others to do the same.

 

Glenn

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Gregg,

 

I found correcting the max_design_MP to 45 also fixes the sound issue as well as the power issue. You can hear the difference when you pull the MP and RPM back.

 

Greg

 

Yes but no...on their version there's no difference on sounds between 30 and 40", as Gregg said and it's still not from 40 to 46", JUST when you pull back the rpms to 2400...there's a tiny bit difference, but not that much...

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Yeah, the sound files are cued to the actual engine parameters. You do anything you want with the MP levels and even sticking in sound files from other aircraft, but it won't make a significant difference. That's something that Carenado is going to have to fix (and note to Carenado, although I know you never read these forums - you had best heed the customers' wishes this time. A LOT of us have reached the ends of our collective ropes with your aircraft, and I for one am done with Carenado/Alabeo aircraft until things improve drastically. You've been warned).

 

Oh, and yes - you (Carenado) had better start making these paintable.

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