PT20J

Chris, this has been a long and interesting thread. From your description in your posts, here's what likely happened: Your airspeed was too high on short final and, perhaps due to the obstructions, you were maybe a bit high also. At some point, as you started using up runway, you forced the plane down to the ground before it was ready. That's the only way to get it to land on the nose wheel, and that's why it bounced. It's also very common, so don't feel bad. This didn't happen with your instructor because an instructor would have seen this coming and had you correct or go around. You only need to satisfy two conditions for a good landing: 1) The airplane needs to be aligned with the centerline, flying level and decelerating a few inches above the runway, and 2) the airplane needs to be in a nose high attitude. If you do that, it will land itself. There are numerous techniques to get the airplane to a point that satisfies those two conditions, and pilots will argue endlessly about which technique is best. Fly safe, Skip

It's just physics: Moment = Force X Distance. Yaw (controlled by the rudder) is a rotation about the vertical axis that passes through the CG. Rotation is caused by an applied moment.

According to my old PA28 service manual, you are correct regarding early Cherokees. Beginning in 1974, bungees were added to the steering system. The nose wheel fairing aerodynamically centers the nose wheel in flight. There's a service bulletin #291 that details the addition of springs if the fairing is removed. I'm not sure how the retractable Cherokees work w.r.t. nose wheel centering. Usually, some sort of mechanism is required on a retractable to keep the nose wheel from getting cocked during retraction.

OK, I’ll bite: why would rudder authority make for better landings? The only thing you need the rudder for is to keep it straight. Which reminds me: one of the not so great aspects of the Mooney design is that the nose wheel doesn’t disconnect from the rudder when fully extended as in many airplanes. And, since the steering is rigid (no bungees) you have to relax rudder pressure when the nose wheel comes down during a crosswind landing or you head for the grass. Bet that’s why the nose wheel deflection - and hence the turning radius - is limited. And, since the nose wheel pivots less than other airplanes, it’s more easily damaged by towing. Skip

That’s backwards. There is less rudder authority with aft CG due to shorter moment arm. That’s why highest Vmc speed for a twin is at aft CG.

Longer moment arm from rudder to CG allows same size rudder to produce greater yawing moment.

I believe it depends on the dash number.

Sorry, I wasn’t clear. $2k is what it cost to fix it.

A Decathlon is "bouncy" -- especially wheel landings. Three things work against you: 1) The landing gear is ahead of the CG, so any vertical velocity at touchdown pitches the nose up increasing the AOA, 2) The tail down force is acting with a moment arm from the stabilizer to the CG until the instant of touch down at which point it acts about the main gear which is a longer arm and this causes a pitch up moment, 3) the spring steel gear is much springier than the original Aeronca bungees. The trick is to fly it down very close to the runway, level off somewhat nose high (the old timers call it "landing on the back side of the mains") so it is slow, and then either roll it onto the runway with a slight forward movement of the stick, or be primed to move the stick forward immediately when it touches on it's own. The forward movement of the stick holds it on the runway so it can't fly and also overcomes the natural instinct to flinch and pull back slightly when it touches down. Skip

Well, I guess we have to define how high it has to be to be called a bounce. When people talk about bouncing an airplane it's usually several feet -- not a little bounce like you get in a drop test.

It cost me about $2K. IIRC they charge about $3.5K for an overhaul/exchange. If the repair price gets up to that level I think they cap it there, but best to call them as things may have changed. Skip

Interesting thread. What causes a bounce? Try this thought experiment: Imagine a crane lifting your favorite Mooney ten feet off the ground. Then the cable breaks. How high will it bounce? I actually witnessed something similar years ago at Mammoth Lakes California. The runway is at 7135' MSL and runs east/west. To the south is Convict Lake in a cut in the Sierra Nevada mountains. When the wind is out of the south at more than about 15 kts, it funnels down over the lake and hits the runway about midfield setting up a nasty wind shear. A friend and I were tightening the tie downs our airplanes due to a gusty south wind when we saw a M20E load up four people and taxi out, so we decided to hang around and watch. Hey, maybe the wind shear wasn't so bad and we could go home after a long day of skiing Mammoth Mountain. The Mooney climbed to about 50 feet and then started bobbing around as the wind shear hit it. If the pilot had put the nose down and landed - the gear was still down - he'd have been OK. Unfortunately, he tried to climb out of it. The plane settled to about 10 feet before it quit. We saw it hit and heard the rumble a second later. It didn't bounce noticeably from our vantage point 500' away. It taxied back to the ramp under it's own power and everyone deplaned and walked to the FBO, presumably to attend to their underwear. We walked oven and casually inspected the plane. About 4 inches of the prop tips were bent and the landing gear doors were bent outward at 90-deg. That's a lot of main landing gear compression! @Shadrach is right: If it bounces, it's flying. That requires excess speed and an increase in AOA which is supplied when the pilot unconsciously pulls back when surprised by the initial ground contact. Skip

Sounds like the KC 192 computer has a problem. Mid-Continent is probably the best bet to repair B-K components. They are an B-K authorized repair center. Autopilots Central and Executive Autopilots send the units there that they can't repair. Mid-Continent recently repaired my computer - works like new. Skip

Stewart Warner (now Mitchell) made mechanical recording tachometer models calibrated for several cruise RPMs, with 2300 and 2566 being the most common. Mooney used the 2300 RPM model. So, at 2500 RPM it will read 2500/2300 = 8.7% fast. I discovered this when I had my '78 J tach replaced. The electric tach that drives a "Hobbs" meter on my '94 J seems to be set closer to 2500 RPM, but I haven't tried to calibrate it. Maybe someone knows. Skip

Usable (not minimum usable) qty is 6 qts. 8 - 6 = 2 minimum. 1E10_Rev_28.pdf

No, but I did note a decrease in oil pressure and an increase in temperature when it got down to 4.

IO-360/O-360 oil capacity is: Max 8, Min 2, Aerobatic engines are dry sump.

Five flight schools I've been associated with had a standard practice of filling Lycoming IO-360, O-360, O-320 engines to 7 qts on the dipstick and adding a quart when it got down to 6. I've run both my M20Js that way with very little oil on the belly from the breather. Skip

American Flyers (nationwide flight school with huge fleet of Cessnas) started using vinyl for their custom paint schemes long ago -- I think they were the first to do it on airplanes. When Cessna restarted C-172/182 production, they consulted with AF and decided to use vinyl in standard production. I've seen vinyl-clad C-172s that have sat out on rental flight lines in the California sun for 15 years that look great. Skip

Did you happen to check the serial numbers? Likely they just sent a new servo.

All autopilots calculate commands to the servos based on modes selected and inputs from sensors. All a flight director does is display the same pitch and roll commands on the attitude indicator. The fact that Garmin chose to put most of the smarts in the G5 rather than the mode controller doesn’t change the basic functionality nor should it affect certification or Garmin’s pricing.

The 3” extensions do require drilling holes in the pedals to attach the brackets, but these holes don’t have any affect on the angle of the pedals which is set by the factory drilled holes in the brackets. @Andy95W idea to adjust at the brake cylinders is something I haven’t tried. I assume he means to shorten the rod ends. The maintenance manual doesn’t seem to describe the adjustment unless I missed something (always possible).

This is a really good point - stick-fixed stability is generally better than stick-free stability, so blocking the rudder pedals to keep the rudder from floating will improve the ride in turbulence. One of the tough problems in designing an airplane without some sort of stability augmentation system is getting the balance of lateral and yaw stability right. Too much one way and you get spiral divergence, and too much the other way and you get dutch roll. Dutch roll is more annoying and difficult for the pilot to counteract and so the nod is usually to decreased spiral stability. The J (the only one I've tried this with) actually has great spiral stability -- slowed down and trimmed to around 90 KIAS straight and level hands off it will eventually enter a descending turn. But as the airspeed builds, the nose comes up as the inherent longitudinal stability kicks in. Around two and a half oscillations of the phugoid and it will settle out in about a 45 degree bank at a constant 90 KIAS or so. This, of course, assumes that it's rigged right and there is no fuel imbalance. So, because of this characteristic, the M20J has a bit of tail wag in turbulence. (This is all likely due to making the vertical stabilizer as small as possible as was discussed in another thread - in aerodynamics, you don't get something for nothing). I can easily see the advantage of the yaw damper if you are going to fly a lot in turbulence. Skip

I found this a bit tricky to adjust. As shown in the picture, the "step" is really where the roller on the microswitch arm rides up on the cable swedge. If you set the switch too far toward the cable, it hangs up a bit on the edge of the swedge when you close the throttle. If you set it two far out, the switch doesn't actuate. And of course you have to adjust this while standing on your head.

I've installed both the 1.5 and 3 inch extensions in different M20Js. It would be pretty hard to imagine screwing up the installation, but you can always double check the drawing. I've noticed that the pedal angle with the 3 inch extensions is such that it's easy to ride the brakes with the seat cranked up pretty high. Skip