PT20J

Lets say I apply left rudder. The airplane will bank to the left because the rudder introduces a yaw rate which causes the right wing to have a greater airspeed (and thus more lift) than the left wing. However, the directional stability of the airplane will eventually cause the yaw rate (and thus the rolling moment) to decrease. There will however be a sideslip, and if the airplane has dihedral, the resulting yaw angle will cause a rolling moment to the right. So, the ability to turn the airplane with the rudder is dependent on the interaction between the two moments. Reducing dihedral improves the ability to bank with the rudders, but decreases lateral stability and increases propensity to diverge in a spiral. So, rather than mess with the dihedral, the usual fix is to add a spring interconnect between the ailerons and rudder. Skip

I agree with your analysis -- I did neglect the sign. Thanks for pointing that out. There are several roll effects that can be produced by rudder deflection: Roll due to sideslip (dihedral effect) Roll due to yaw rate (differential airspeed between wings) Rolling moment due to rudder deflection (discussed above) Aileron deflection due to rudder deflection (due to the interconnect springs) Skip

For simplicity, I just lumped all the effects into “torque.” But you are correct that there are several forces at work. However, it is incorrect to say that rudder does not counteract torque. The aerodynamic center of the vertical tail is above the aircraft roll axis and so the force generated by rudder deflection does produce a rolling moment. Skip

Yes, it’s a kludge.

If it's the Micky Mouse arrangement on the throttle like on my M20J, it's a pain to get it just where you want it. I went up and set up in the landing configuration and figured out where I wanted the throttle to be positioned when it went off and then marked the throttle shaft with a sharpie. Back on the ground, I could fiddle with the switch adjustment until the switch would close when the throttle it the mark.

I have a small group of aeronautical engineer friends that are kind enough to answer my questions and beat around ideas from time to time. I try not to bug them too often. But Ron always seemed happy to hear from me and answer whatever question I had and gently point out the flaws in my understanding. I will truly miss our interactions which were always so informative and pleasurable. Skip

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

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

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.

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

I think you are overthinking this A published segment of an IAP will have a published minimum altitude. If you are on a published segment and cleared for the approach you may descend to the published altitude. If you are within the TAA you are on a published segment and may descend to the published altitude when cleared. Only if you are NOT on a published segment when cleared for the approach must the controller issue an altitude to maintain until established on a published segment.

ForeFlight can display on the map the locations of the current towers it is receiving in flight.

The roller lifters also require a different cam with a different ramp profile. This causes the MAP to be a little higher at idle. Lycoming couldn't get the turbocharged engines to meet rated power with that profile and I learned in the factory class that they use the DLC lifters in turbos.

Look at the excerpt I posted above from 7110.65. The note that begins at the bottom of page 4-8-5 states: "Aircraft that are within the lateral boundary of a TAA, and at or above the TAA minimum altitude, are established on the approach and may be issued an approach clearance without an altitude restriction."

The airframe can be a few degrees warmer than the ambient temperature because of ram effects. Garmin (at least on the G3X) corrects RAT (ram air temperature measured at the probe) for true airspeed heating effects and displays a corrected OAT. I've noticed that I can fly at 0 deg C OAT in clouds and never pick up ice. There is an option to display RAT on the G3X data bar. Skip

I wonder how many Mooneyspace threads this issue will spawn? Maybe it will set some sort of record.

Interestingly, it says ”appropriate weights”. I assume that would be interpreted as MGW. Here’s the complete section on stalls and spins including paragraph 3.85 referenced in the stall section.

The Cherokee series has the most benign stall characteristics of light GA airplanes I've flown. Held in a power off stall, the nose just bobs up and down as it flies in and out of stall and you can keep the wings level with the rudder. I can hold my M20J in a stall and keep it straight the rudder, but it's like standing on a beach ball -- very touchy, and eventually it will get away from me and drop a wing. This is not the same as it dropping a wing abruptly at the break, but it does show that the Mooney wing drop characteristics are very sensitive to sideslip. Note also the specified technique for the test: Trim to 1.4 Vs and decelerate at 1 (knot/mph, at these speeds it doesn't matter) per second. If you don't trim for 1.4, the stick forces are high and if you haul back it will stall at a higher speed (due to g-load) and stall more abruptly. It never hurts to review the spin recovery technique :PARE (Power off, ailerons neutral, rudder full opposite rotation, elevator briskly forward). According to CAR 3, all normal category airplanes had to be placarded against spins unless they are characteristically incapable of spinning. Nonetheless, CAR 3 required that they be shown to recover from a one turn spin in one and a half turns. Spins are not fully developed until 1.5 - 2 turns and a fully developed stall may be harder (or impossible) to recover from. But keep in mind that Mooney probably only tested this once per model and that would have been with a new, perfectly rigged airplane. Skip

CAR 3 certification limits were for power off and power not less than required for a 300 fpm climb with gear up, takeoff flaps. They had to be done with gear up and down, flaps in any position, and least favorable CG. The procedure calls for trimming to 1.4 Vs, pitching to slightly below stall speed and the reducing speed at the rate of 1 mph per second until the stall break.

The right rudder counteracts the torque if you keep the ball centered. The decrease in wing lift at the stall doesn’t change that. But it takes increasing rudder as the airplane slows because the torque is (mostly) constant but the rudder becomes less effective.

Stall strip location can only be confirmed by flight test. There is a procedure in the service and maintenance manual. Certification limits are 15 deg max roll within one second of the stall break. M20J service manual has the same limits. Mooney flight tested each airplane and placed the strips accordingly for each due to manufacturing tolerances. This should have been done again after missile conversion. Not sure what has changed, but if you were coordinated at the stall it shouldn’t behave as you described.

I don’t think so. I don’t believe anything has changed lately or is likely to and there is a link to this list in the current SBS description document. Every GBT (ground based transceiver) broadcasts its lat/long and ID as part of the FIS-B uplink and UATs are supposed to provide a means to display this information for all stations being received, so it’s never been that big a secret. But, I think in the past, someone may have just been nervous about putting all the information in one place. Skip

Ever wonder where those things are? Here’s the current list from the FAA. Apparently it was provided in response to a FOIA request (maybe that explains the apparently random sorting and the fact that the .xlsx file was converted to .pdf before posting). https://www.faa.gov/foia/electronic_reading_room/media/ADS-B_Ground_Stations_as_of_08-31-2018.pdf Stratux went to the trouble to plot the locations on a map (unfortunately, they didn’t include the altitude tier). http://towers.stratux.me Skip

No, I never had an issue in ALT or PIT. IAS can hunt a bit if the airspeed is increasing or decreasing at engagement, or if the thumbwheel is rapidly moved to a setting greater than +/- 5 KIAS after engagement, but it will generally settle out after 2 cycles which is the natural long-term longitudinal response of the airplane. I replaced both yoke eyeballs when I re-did the panel. I was amazed at how much greater friction the old ones had. I do keep all the heim bearings and trim components lubricated and occasionally apply some silicone spray to the control shafts which are chrome plated and smooth. I have followed Mooney’s current recommendation and have not lubricated the new nylatron eyeballs. Skip

I had a need to go to KPAE last winter. It was above the LPV minimums for the RNAV Y 16R approach when I took off, but as I was getting vectored ATIS advertised 200-1/2. A Boeing Co. jet ahead went missed. At 200’ DH all I could see was the inside of a cloud. Power, TOGA, get the heck out of there. Next day, I shot the same approach to 500 overcast. I took note of the environment at 200’. That’s low. Gotta be on your game there. When I used to do a lot of IPCs, I observed that often pilots not used to missing would put in power, but not pitch positively to climb attitude and instead continue a descent. Apparently the fact that the engine was making a lot of noise caused them to think they were climbing. One feature I really like with the GFC 500 is that TOGA does not disconnect the autopilot but commands a straight ahead climb. Skip