Yaw Damper question in a J

[WaynePierce]

I just purchased a GFC 500 to replace my currently in-op KAP 150 (sometimes it does, sometimes it doesn't) I've never had the opportunity to fly with a Yaw Damper but the 500 has the ability. Would you choose to have it connected in a J? Why? Currently I've had the avionics shop order the servos to do the same as the 150... Roll, Pitch and auto trim. I'm assuming to have the Yaw Damper installed would take another servo for the rudder which I currently do not have.Thanks...

[N201MKTurbo]

I wouldn't pay for it. The only plane I've flown with a yaw damper was a T310R. That plane will Dutch roll a bit in the bumps and it helps. But, I've never been flying in a Mooney and thought "I wish I had a yaw damper"

[WaynePierce]

2 minutes ago, N201MKTurbo said:

I wouldn't pay for it. The only plane I've flown with a yaw damper was a T310R. That plane will Dutch roll a bit in the bumps and it helps. But, I've never been flying in a Mooney and thought "I wish I had a yaw damper"

Thank you, that's what I was thinking, but I was watching some "instructional" videos on the GFC 500 and there was a Mooney J driver video and he had the YD installed and said he was glad he had it... I wondered why...

[N201MKTurbo]

3 minutes ago, WaynePierce said:

Thank you, that's what I was thinking, but I was watching some "instructional" videos on the GFC 500 and there was a Mooney J driver video and he had the YD installed and said he was glad he had it... I wondered why...

IDK, I honestly rarely touch the rudders unless I'm maneuvering. But then again, I may be subconsciously using them in the bumps and just don't think about it. Besides, there's nothing better to do while riding in the Mooney, might as well fly it some.

[kortopates]

I like mine in a K, same fuselage. YD makes it easier to climb to altitude but my climbs are much longer than yours but its also turn out to be a big plus in turbulence. Out west turbulence is common.
but yes it’s another servo install just like the others back in the tail.


Sent from my iPhone using Tapatalk

[ArtVandelay]

I didn’t get it, J is very stable and I don’t fly in turbulence as a rule. Now if you had a V tail Bo, then definitely.

[PT20J]

I think it depends more on your. Some people want every bell and whistle they can get. Nothing wrong with that. I'm kind of at the other end of the spectrum, though. Everything in my airplane is there because I need it or it adds redundancy against failures. Every piece of equipment has overhead associated with learning how to use it and to maintain it and it will also have failure modes that have to be understood and planned for.

I never felt the need for a yaw damper in my M20J before I installed the GFC 500, so I didn't have one installed when the GFC was installed.

Reading some threads, there seems to be some confusion about what a yaw damper does and does not do. It's not intended as a replacement for rudder trim. It is intended to dampen out yaw oscillations. Some airplanes have more objectional yaw dynamics and roll-yaw coupling (aka Dutch roll) than others. I'll bet Bonanza pilots love it.

One nice thing about the GFC 500 is that it is a modular design so it's easy to add the yaw damper later if you want. Just tell the installer to set up the wiring so that it is easy to extend the CAN bus and power to the extra servo.

Skip

[PT20J]

12 minutes ago, ArtVandelay said:

I didn’t get it, J is very stable and I don’t fly in turbulence as a rule. Now if you had a V tail Bo, then definitely.

Actually, a handling qualities test pilot (Roger Hoh) once told me that the Dutch roll is about the same in the straight tails and the V-tails. (At the time, he was flying a V-tail). Everybody blamed the tail, but apparently it was inherent in the basic design.

[A64Pilot]

15 minutes ago, PT20J said:

Actually, a handling qualities test pilot (Roger Hoh) once told me that the Dutch roll is about the same in the straight tails and the V-tails. (At the time, he was flying a V-tail). Everybody blamed the tail, but apparently it was inherent in the basic design.

It’s true I flew once in the back of an A-36 once, I will not again. I think it’s the very flat bottom or maybe just not enough vertical surface area back there.

I think the tail is as big as it can be on an A-36 without a complete redesign.

‘But if you ask an A-36 owner they will deny it as does the Aviation press.

[WaynePierce]

16 minutes ago, PT20J said:

I never felt the need for a yaw damper in my M20J before I installed the GFC 500, so I didn't have one installed when the GFC was installed.

Reading some threads, there seems to be some confusion about what a yaw damper does and does not do. It's not intended as a replacement for rudder trim. It is intended to dampen out yaw oscillations. Some airplanes have more objectional yaw dynamics and roll-yaw coupling (aka Dutch roll) than others. I'll bet Bonanza pilots love it.

One nice thing about the GFC 500 is that it is a modular design so it's easy to add the yaw damper later if you want. Just tell the installer to set up the wiring so that it is easy to extend the CAN bus and power to the extra servo.

Skip

I don't have it now and didn't think I needed it but then I started watching YouTube... My J doesn't have rudder trim, I wish it did because sometimes when I'm straight and level the ball is a little on the left. Digitally and analog. Not much but in my Cherokee I had rudder trim and it was very handy.

[donkaye]

Per Garmin:  Optional Yaw Damper (YD) — The yaw servo provides Dutch roll damping and turn coordination in response to yaw rate, roll angle, lateral acceleration, and airspeed.

The YD combines 4 inputs in damping yaw.  I don't think the BK YD in the Encore does that.  The GFC 500 YD can handle yaw in turbulence better than I can.  While I can fly the airplane better than the AP in turbulence, I keep the YD on because it does a better job at handling it than I do.  For the extra money for the servo and minimal added labor because the shop is already in there, I'd add it.

[Pinecone]

A buddy was in a partnership in a Cherokee 180D.

One time we were flying up to a breakfast in NY.  I was flying from the right seat.   He kept looking at the instruments and me and frowning.  I asked was what wrong.  He said, "You fly my airplane 4 knots faster at the same power setting."

I have flown tail wheel aircraft, Gliders (Comm, CFI), and helicopters (Comm, CFI), so tend to use my feet when flying.

[PT20J]

2 hours ago, WaynePierce said:

I don't have it now and didn't think I needed it but then I started watching YouTube... My J doesn't have rudder trim, I wish it did because sometimes when I'm straight and level the ball is a little on the left. Digitally and analog. Not much but in my Cherokee I had rudder trim and it was very handy.

If it is rigged right, the ball should be centered in cruise and require a bit of left rudder in a dive. 

It's important to make sure the airplane is rigged correctly and that as much control friction as possible has been eliminated before autopilot installation. I understand that Garmin spent a fair amount of effort on this with each test airplane before installing the autopilot for certification. Installers probably not so much. How many avionics shops are even equipped to check Mooney rigging? 

Even when new, the Mooney controls have a fair amount of friction. I know everyone thinks the push pull tubes are better than cables because cables can stretch. But, cables run through pulleys with ball bearings. The Mooney aileron tubes run through guide blocks with some grease smeared on them at numerous points through the wings. At high airspeeds, the low pressure on the top of the ailerons causes them to want to float up which puts the tubes on both sides in compression and this flexes them slightly increasing the friction. Roger Hoh flight tested the Predator and told me that it was so bad in that airplane that the stick would stay wherever you put it with very little centering force. Another problem with the push pull tubes is that there are a lot of rod ends, and they develop lost motion over time as they wear.

The Mooney elevator control friction is worse than the ailerons. Much of the problem is in the eyeball bearing where the control shaft penetrates the control panel. Mooney has had at least three iterations of the penetration, chrome plated the shaft, and tried various lubricating recommendations. The black nylatron eyeballs currently in use are supposed to be self lubricating and kept dry, presumably to avoid crud buildup. I put new eyeballs in my panel when I had it apart and they had significantly less friction than the ones that I removed that were only 1200 hours old but had been lubricated with who knows what. Even with all this effort there is enough friction to create a measured trim band of about 5 KIAS at 65 KIAS. 

Skip

 

[PT20J]

I think Dutch roll is a Beech thing. My wife and I once flew a Duchess from Palo Alto CA to Santa Fe NM and the ride wasn't great out over the desert southwest.

One trick is to recognize that there are two different stability criteria: stick-fixed and stick-free. Stick-free is where the control surfaces can float and that's what we normally experience when we fly. Stick-fixed is when we rigidly hold the controls so that the control surfaces cannot move at all. Stick-fixed stability is generally greater than stick-free because the float is destabilizing.

So, in the Duchess, I used both feet to block the rudder pedals so that the rudder could not float and the Dutch roll calmed down considerably. Think of it as a poor man's yaw damper 

[laytonl]

My wife has commented that “we have less tail wagging with the new autopilot”.   Quite frankly I’ve never noticed much tail wagging in turbulence, but she had.  It is interesting to rest my feet on the pedals and feel the YD working.  Lee

[Pinecone]

I think that more pilots should spend time in both a tailwheel aircraft and a glider.  Both teach rudder skills that most pilots lack. 

Helicopter also instills more foot work, but a bit more expensive.

[WaynePierce]

20 minutes ago, Pinecone said:

I think that more pilots should spend time in both a tailwheel aircraft and a glider.  Both teach rudder skills that most pilots lack. 

Helicopter also instills more foot work, but a bit more expensive.

I have less than an hour in a Cub, but I agree with you 100% and would love to get a tail wheel and glider endorsement!

[rbp]

38 minutes ago, WaynePierce said:

tail wheel and glider endorsement

TW is an endorsement. G is a category add-on rating

[dzeleski]

On 12/2/2022 at 3:44 PM, WaynePierce said:

I just purchased a GFC 500 to replace my currently in-op KAP 150 (sometimes it does, sometimes it doesn't) I've never had the opportunity to fly with a Yaw Damper but the 500 has the ability. Would you choose to have it connected in a J? Why? Currently I've had the avionics shop order the servos to do the same as the 150... Roll, Pitch and auto trim. I'm assuming to have the Yaw Damper installed would take another servo for the rudder which I currently do not have.Thanks...

I think it’s worth it in a J. I’ve turned it off a few times just to see what it feels like and it makes things smoother and more comfortable for everyone on board. In IMC with less experienced passengers it makes a big difference for those passengers. Really for me it’s just one less control input I need to worry about and can focus on making sure everything is setup correctly and doing the right thing. With the yaw damp on as well as the whole AP the thing is just on rails.

And really let’s be honest here being able to say “Yaw Damp On” during climb out is worth the purchase price alone. 

[bmcconnaha]

The GFC500 that I had I my J had a yaw damper.  I found it nice, and would do it again, but, be realistic with expectations.  You’ll still need right right rudder in even a low angle cruise climb.  And still need a little left rudder in descent.  Now, I feel the Mooney is very stable, but the yaw damper is noticeable in turbulence, and I preferred to have it on.  All in all, I’d do it again.  

[Pinecone]

And since Mooney owners are about speed, keeping the tail in check is worth a few knots.

 

[rbp]

On 12/2/2022 at 4:12 PM, kortopates said:

also turn out to be a big plus in turbulence

I have an M with the YD.  definitely makes a difference in turbulence

[dzeleski]

11 hours ago, bmcconnaha said:

The GFC500 that I had I my J had a yaw damper.  I found it nice, and would do it again, but, be realistic with expectations.  You’ll still need right right rudder in even a low angle cruise climb.  And still need a little left rudder in descent.  Now, I feel the Mooney is very stable, but the yaw damper is noticeable in turbulence, and I preferred to have it on.  All in all, I’d do it again.  

When my yaw damp is on I don’t have to touch a single peddle at any phase of flight. Even during climb or decent, the ball is always centered.

[bmcconnaha]

16 minutes ago, dzeleski said:

When my yaw damp is on I don’t have to touch a single peddle at any phase of flight. Even during climb or decent, the ball is always centered.

Dang, I must have not one, but two weak servos.  Lol 

[PT20J]

30 minutes ago, bmcconnaha said:

Dang, I must have not one, but two weak servos.  Lol 

The yaw damper is not supposed to be an automatic rudder trim. It will keep the ball centered to coordinate turns and compensate for minor out of trim conditions. If you are significantly out of trim, as in a climb if you don’t have rudder trim(or have it but don’t use it), the yaw damper may not be able to center the ball. Even if it can, you are putting needless strain on the servo asking it to maintain a constant torque for a prolonged period. 

Skip