Mooney drivers who have the Garmin GFC 500

[gsxrpilot]

3 hours ago, 201Steve said:

fly a J, arguably the “most powerful” of the mid bodies

Really? I'd say not even close. 

Rocket, Missile, Encore 252, 231... M20J, F, G.

[201Steve]

43 minutes ago, gsxrpilot said:

Really? I'd say not even close. 

Rocket, Missile, Encore 252, 231... M20J, F, G.

Yeah for sure, all around poor description. Side bar to the point, what aircraft and why is it yawing in in cruise

[Diesel 10]

I got the GFC500 + 750 + 2 x G5s installed earlier this year. Similar to others, I couldn't be happier.  I've had a chance to fly the setup quite a bit including a good amount of "actual" approaches etc.  I really love it.  Previously I was using a 430 and a KFC150.  Not bad but the KFC150 was at End of Life.  The GFC500 setup is an order of magnitude more sophisticated.

I have had a couple of experiences of some mild altitude oscillations/hunting during Altitude Hold.  I haven't had an opportunity to do any diagnosis on this.

Trevor

[M20F]

2 hours ago, adverseyaw said:

Sadly no plane with a propeller flies squarely -- they all fly a little sideways and we just have to tweak the controls to get them as close to straight as we can.

I want to get in on the start of this beating (I jest slightly, but I know my Mooneyspace!), but would highly disagree.  Lot of types, years, etc. and no issues.  Obviously P-Factor applies left and right.  In cruise though there should be no issue and the ball centered.  
 
I rarely hand fly because I am very lazy and really just fly to go places these days.  When I do though my F is on rails when trimmed.  I can go hands off for 5-10 mins before it wobbles itself into a need for correction (and that is a little aileron or elevator; never the rudder).  Same is true in a AC560, C150, and the list goes on. 
 
If you are stepping on a rudder peddle in flight, you have a rigging issue. 
 

[carusoam]

Adding a single data point to the fire...

The O... with rudder trim...

1) Has a T/O climb setting somewhere to the right, half scale...

2) It cruises near dead center on the trim scale... clicking the button to get it just right...

3) Oddly enough... The P-factor is real... and in smooth air during the descent... the trim is pushed to the left... about 1/4 scale...
 

4) I never noticed this during descent in a decade of M20C flying... it had to have been there... just no scale to compare it to...

5) Of course I would have to have data to share regarding AOA or attitude.... as they are not identical in my climbs and descents either...

 

PP thoughts only, not a CFI...

Best regards,

-a-

[PT20J]

On 8/30/2020 at 12:39 PM, adverseyaw said:

Sadly no plane with a propeller flies squarely -- they all fly a little sideways and we just have to tweak the controls to get them as close to straight as we can.

Let's think this through. Propellers exert various forces on the airframe due to gyroscopic effects, torque, p-factor and spiraling slipstream. If an airplane is flying sideways, there must be a sideways force. Where would this force originate and how is connected to the propeller? Let's consider an airplane in cruising flight. Torque acts axially and cannot generate a side force. P-factor is negligible as the ascending and descending blades are at essentially the same angle of attack in level flight. There is no pitch rate or yaw rate to created gyroscopic precession. Thus, we are left with the spiraling slipstream which, by its impingement on the vertical tail, creates a side force. If unchecked, this would cause the airplane to fly along in a sideslip. However, the pilot would naturally counteract this situation with rudder input nulling out the net side force. This would require constant rudder pressure to keep the ball centered (wings level), and would be tiring on a long flight. Fortunately, engineers have designed means (usually a slight canting of the vertical tail or offset of the engine thrust line) to generate the counterbalancing side force without holding rudder pressure. This solution is exact only for a single speed and power setting, but the optimum is so broad that it works well over the normal range of cruise speeds. Faster speeds, as in a high speed descent, will require compensating left rudder, and slower speeds, as in a climb, will require right rudder. Of course, if you have rudder trim, you can trim for straight flight at any speed.

My M20J cruises with the ball centered (feet on the floor) and wings level for several seconds (hands off). Here's a good article about Mooney rigging:

201407 Control Rigging.pdf

Skip

[adverseyaw]

I think we're speaking the same language, although I could have used more precision in my last post. :-) Unlike a paper airplane, which can be built in a way that truly introduces no asymmetric loads, a single-engine piston airframe is always subject to left-turning effects. The designer building in offset in the motor mount and vertical stabilizer is evidence of this, and that evidence is the beginning of the story, not the end.

In the quest for more speed and less load on my yaw damper, I will heed the prevailing advice and will have my rudder rigging checked at annual. :-)

But for the physics of it, I agree most with the statement that this rigging will be for a particular configuration (a point within cruise) and will not necessarily apply to the rest of the envelope. If we differ on whether the cruise envelope can be adequately covered by a single rigging, this is a question that can be resolved with measurements! Then we can just argue about what "cruise" is ;-)

[PT20J]

The lateral-directional motions can get pretty complex. Lets say you are flying along and suddenly decide to stomp on the right rudder and then release it. The nose will yaw to the right. The rate of yaw will increase until you release the rudder and then it will stop and reverse as the natural directional stability wants to reduce the sideslip. The sideslip will cause a rolling moment to the right due to dihedral effect and the yaw rate will cause a rolling moment due to the difference in speeds of the two wings. If you try to correct the roll with aileron, the adverse yaw introduces a yawIng moment and if you use the rudder the fact that the vertical tail is above the CG will introduce a roll. So, in anything but calm air, the airplane is always wallowing around a bit. Some are worse than others especially if the roll-yaw coupling devolves into a Dutch roll. If I get a GFC500, I’m getting a yaw damper. Mooneys aren’t terrible in turbulence, but why not get some help to smooth out the natural dynamics?

One trick if you don’t have a yaw damper is to remember that stick-fixed stability is generally greater than stick-free stability. I was getting a terrible ride over the Arizona desert on a warm afternoon in a Duchess when I thought to block the rudder pedals with both feet preventing the rudder from floating. The ride improved considerably. 

Skip

[Missile=Awesome]

Is that news to anyone that resting feet on rudder pedals in turbulence helps?

[PT20J]

Anyone miss CWS?

[Niko182]

15 minutes ago, PT20J said:

Anyone miss CWS?

No

[donkaye]

I thought I would miss it, but I don't.

[Bob - S50]

9 hours ago, PT20J said:

Anyone miss CWS?

No.

[carusoam]

CWS... Never found any value to it...

Was it used for something in transport planes in the 60’s or something?  Familiar to somebody?

Turning the AP off, then back on When needed, thirty seconds later, seemed pretty easy...

Each function is independently controlled... Altitude function, and directional function... push the button, it’s on... push again it’s off...

Flying around a cloud required holding the button down for a long time...

Did I miss something?

Best regards,

-a-

[Rmag]

My Mooney has a KFC 150 CWS, I hardly ever use it.  One of the things I don’t like is that it is tiny and impales my thumb tip.  Are they all like that?

[carusoam]

Rmag,

There is a tiny black cap that is supposed to cover the metal pin... a tad bit friendlier for your thumb...

Finding a cap for that is probably a simple search for electronic switch caps...

It would be extra helpful if we knew who the switch manufacturer is...

Some MSers know these details... stand by.

Best regards,

-a-

[ZuluZulu]

4 minutes ago, Rmag said:

My Mooney has a KFC 150 CWS, I hardly ever use it.  One of the things I don’t like is that it is tiny and impales my thumb tip.  Are they all like that?

My KAP 150 has that little button too, but I can't remember if I have the plastic cap @carusoam mentioned.  I think I would remember the experience of my finger getting impaled when pressing it, so I'm guessing it probably does.

[gsxrpilot]

Just now, ZuluZulu said:

My KAP 150 has that little button too, but I can't remember if I have the plastic cap @carusoam mentioned.  I think I would remember the experience of my finger getting impaled when pressing it, so I'm guessing it probably does.

I'm certainly missing the little cap. It's painful to use the CWS so I never use it.

[Scottknoll]

I had the cap come off my PTT button. It was not fun to talk on the radio... I believe this was the cap used to replace it and might be the same for the CWS.

https://www.mouser.com/ProductDetail/Electroswitch/SW53AA2?qs=5muX3C0yOnj5E%2FJxlK6wTg%3D%3D

[carusoam]

Sk’s data sheet with what the button cap looks like...

https://www.mouser.com/datasheet/2/128/minp17-5206.pdf

Mouser is a great resource even if it is a different cap...

Best regards,

-a-

Edited September 11, 2020 by carusoam

[HIghpockets]

When I had my GFC 500 installed the CWS button was converted to a TOGA button. I find it very convenient.

[Rmag]

9 hours ago, HIghpockets said:

When I had my GFC 500 installed the CWS button was converted to a TOGA button. I find it very convenient.

I was thinking about doing that if/when I do a GFC500 upgrade. Were you able to re-label the switch or just leave it as is?

[ZuluZulu]

11 hours ago, HIghpockets said:

When I had my GFC 500 installed the CWS button was converted to a TOGA button. I find it very convenient.

I was told the TOGA button has to be placed close to the throttle, so we're looking to repurpose CWS as a push-to-command button for activating Teligence.

[Rmag]

1 hour ago, ZuluZulu said:

I was told the TOGA button has to be placed close to the throttle, so we're looking to repurpose CWS as a push-to-command button for activating Teligence.

It does not have to be placed close to the throttle.  It just has to be within easy reach of the hand that normally operates the throttle.

The install manual states:

Installation of the GFC 500 Autopilot also requires a Go Around switch. See Section 3.2 for switch part number. The installation of the Go Around switch must meet the following criteria;
• Must be within easy reach of the hand that normally operates the throttle
• Must be easily located by the pilot without visual reference
• Must be located so that any action to operate switch will not cause an unintended input
to the aircraft flight or engine controls
• Must be located to minimize inadvertent operation and interference from other nearby
switches or devices
• Switch must be clearly labeled “GO AROUND” as defined in Section 3.4.77

[dan nephin]

On 8/21/2020 at 4:18 AM, HIghpockets said:

I have the GFC 500 and two G5s. Best upgrade I ever made. 

+1 on that! Had mine installed by trilogy and Don Hague in chilliwack its a great combo!