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Everything posted by Vance Harral
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That black-colored block is exactly what's found in our 1976 M20F, which best as I can tell is factory original. I think Mooney used this arrangement for a short period of time in the mid-70s, after the older "eyeball" carrier, and before the modern "ring" in your photo of the 1979 J model. One of our blocks is a bit worn, which leads to some play and chattering in the fore/aft movement of the yoke. It can be eliminated for a while with a very light coating of TriFlow or other silicone-based lube on the shaft, which I like to think doesn't carry much grit into the block. But it's probably true that over time, repeated applications of lubricant are just making things worse. We did purchase a replacement block from LASAR several years ago. But it turns out to be so much trouble to install it that we've just kept the part on the shelf, until such time as there is other reason for significant disassembly of the yoke and/or shaft mechanisms.
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Is there confusion with Vx on our vintage M20s?
Vance Harral replied to Nukemzzz's topic in Vintage Mooneys (pre-J models)
I stand corrected, my copy of the manual does have that sentence. I just missed it, buried as it is at the very tail end of the verbiage, and with no corresponding graph or table. Thanks for the correction. As others have noted, the manual doesn't actually state the gear/flaps configuration at which 80 MIAS achieves best angle. People are speculating above that it's with gear down and flaps in the takeoff position. But the manual doesn't actually say that, and that number seems to be at odds with my experiments in our F model. The E and F are not exactly the same, though, despite being pretty similar. I stand by my position that leaving the gear down while topping a 50-ish foot obstacle is the most practical tradeoff for obstacle clearance. Again, if raising the gear during that 6 or so seconds is really the difference between clearing the trees or not, you shouldn't have taken off in the first place. -
Is there confusion with Vx on our vintage M20s?
Vance Harral replied to Nukemzzz's topic in Vintage Mooneys (pre-J models)
Is there confusion with Vx in our vintage M20s? I say yes, absolutely. Permit me to elaborate. I don't own an E model, but I sometimes give training in them. I have a copy of the 1966-67 M20E "Super 21" Owner's Manual dated March 1967 for S/Ns 832-1308 and 67001-67062. I don't see "Vx" or a "Best Climb Angle" speed published anywhere in that manual. If someone can post a screen shot from that manual or a later M20E edition showing a published Vx, please do so. Best as I can tell, Mooney simply didn't publish one for the M20E, and that's what I teach. But I want to know if I'm wrong. In any case, I do own a 1976 M20F model, and the October 1975 revision of the M20F Owners Manual has a Climb Performance table which charts both "Best Angle" and "Best Rate" climb speeds. It claims the Best Angle speed is 94 MIAS/82 KIAS at all altitudes, while showing Best Rate to vary from 113/98 at sea level to 96/83 at 16K pressure altitude. But... that chart has a Conditions section which says those speeds are with gear and flaps up. In contrast, the Takeoff Distance chart specifies wing flaps in the takeoff position, and the "Normal Procedures" says not to raise flaps until clear of obstacles. It also says not to raise the gear until you can do so safely, which obviously means at least the first few feet of takeoff occur with the gear down. Conclusion: the chart in the M20F Owners Manual which specs a Best Angle climb speed isn't actually applicable to takeoff and obstacle clearance! As a CFI, this leaves me with a dilemma in teaching proper short-field technique in vintage Mooneys. While I don't necessarily claim it's the "one true way", I teach short field takeoff technique in vintage Mooneys with flaps set to takeoff and gear down until 50' AGL; then we raise the gear, then the flaps. Using takeoff flaps matches what the Owners Manual prescribes. My rationale for leaving the gear down thoughout the 50' climb is, during the roughly 6 seconds it takes to do this while pitched for Vx in that configuration, I want the pilot fully focused on pitch control, and spring-loaded to shove the nose down if the engine takes a holiday (or even hiccups). Neither of those things is well served by taking one's hand off the throttle and trying to raise the gear, especially in a Johnson bar Mooney. So what speed should one use for this 50' climb with gear down and takeoff flaps? The M20F Owners Manual doesn't say. Even if I changed technique to raise the gear "instantly", I still don't have a published Vx with flaps set to takeoff, which is what the manual prescribes until the obstacle is cleared. Therefore, one has to determine Vx experimentally. My partners and I have run this experiment several times in our M20F, and we find Vx with takeoff flaps and gear down at our home airport (KLMO, elevation 5050), is about 73 MIAS. Yes, 73 MPH indicated. Yes, that's uncomfortably slow. Not only is it uncomfortably slow, it also requires an uncomfortably high pitch attitude and deck angle. It really does achieve the shortest distance over a 50' obstacle, but it's a vulnerable configuration, and none of us like it. When we practice true short field technique, we expect our students (and ourselves) to immediately lower the nose to a Vy climb attitude as soon as the obstacle is cleared. Note: many pilots I work with on short field takeoffs hold Vx far too long. The mythical 50' obstacle isn't much higher than the top of a tall hangar, and since you're going to be climbing in the neighborhood of 500 fpm, it only takes 1/10th of a minute to get there. That's about 6 seconds. By all means, clear the obstacle, but it hardly takes any time at all, and you shouldn't keep staggering along in a high pitch attitude after you've done so. It increases risk for no good reason. I've spoken with other Mooney drivers about our findings, and none of them have hard data to dispute the 73 MIAS number. But some of them say they're just not willing to use that slow a speed and that high a deck angle right after liftoff, and it's difficult to argue with that advice. Were I a DPE evaluating a candidate's short field takeoff performance in a Vintage Mooney, I'd have no quarrel with a candidate who told me 80 MIAS was their best tradeoff between performance and safety, even if a slower speed might achieve a slightly shorter obstacle distance. One thing I try to drive home to my students about takeoff and landing performance numbers is that if tiny variations in speed or technique are actually the difference between going into the trees or not, you've already committed the cardinal sin of a judgement error. Just my $0.02, interested to continue reading what others have to say.- 50 replies
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Main gear retraction pivot
Vance Harral replied to Nukemzzz's topic in Vintage Mooneys (pre-J models)
I hadn't realized the SB was only applicable to F and J models. My guess is that's due to the higher gross weight of 2740 lbs in the F/J, vs. the 2575 lb gross of the C/D/E. Higher weights put more force on the gear. -
Cessna resumes Turbo 182 production
Vance Harral replied to LANCECASPER's topic in Miscellaneous Aviation Talk
I think it's mainly the flight school environment, which Cessna continues to heavily influence. My hypothesis goes like this: in training, there's rarely good reason to pay the extra cost per hour for a 182 vs. a 172, for any certificate or rating. I know of at least two local flight schools that keep a single 182 on the line, while also running a fleet of 172s. The former are rarely flown and can be booked on a few hours' notice. The latter have to be scheduled days or weeks in advance. Sure, some of the students talk about "stepping up" some day, but in the short term there's no value for the extra cost, and the insurance requirements to solo don't help. Meanwhile, airplanes smaller/lighter than a 172 seem to have viability problems: not enough useful load, etc. That leaves the 172 as the sweet spot for actual training. Hence, lots of demand from flight schools. Turning to demand outside flight schools, you have a bunch of potential owners that completed their training in a 172, who might consider a 182. But the younger folks going directly to the airlines aren't going to buy any airplane at all - it wouldn't be affordable to them even at half of current market prices. Amongst the remaining older/wealthier crowd, most of them understand it's difficult to operate a piston airplane as a viable business tool or personal traveling conveyance, and are only interested in the hobby aspect. And if a "well loved" 172 at the flight school was good enough for their training, then a "nice" 172 is good enough for their follow-on hobby flying. Sure, a 182 has better utility for not much more investment. But that's irrelevant if the mission is to periodically fly around the patch with zero or one other buddies for $100 hamburgers and the like, so why pay the extra cost? This phenomenon isn't unique to Cessna. One might similarly ask why the PA-28 is so sought after when it can't hold a candle to the PA-32. I don't have hard data to back this up, it's just a gut feel based on listening to my and others' students around the flight schools talk about long-term ownership plans. -
8 Zircs per main gear; I don't believe you ;)
Vance Harral replied to TheTurtle's topic in Vintage Mooneys (pre-J models)
I ordered a tube of Aeroshell #7 from Aircraft Spruce at the beginning of September, and I'm still waiting on the order to be filled. I need it for our annual in April, and I'm starting to think I need to look elsewhere. -
Main gear retraction pivot
Vance Harral replied to Nukemzzz's topic in Vintage Mooneys (pre-J models)
A neuron fired, and I remembered the one other thing I wanted to contribute to this thread. The IPC specs ordinary AN hardware for the landing gear side brace bolts; but AD 78-15-02 requires following the instructions in SB M20-212 to replace those with NAS 1306 high strength bolts, see https://www.mooney.com/wp-content/uploads/2020/12/SBM20-212.pdf. If you're ordering new hardware for these bolts, order the NAS 1306 hardware, not the AN hardware spec'd in the IPC. If you order your hardware from LASAR, they'll likely send the correct hardware. If you're just ordering from Aircraft Spruce based on the IPC, you can wind up accidentally un-doing an AD. -
Main gear retraction pivot
Vance Harral replied to Nukemzzz's topic in Vintage Mooneys (pre-J models)
I went through a similar exercise a few years ago. You might find this thread I posted at the time helpful: -
Out of curiosity, can you guys elaborate on what undesirable behavior occurs in a GFC500 installation without the yaw damper? I haven't flown or ridden in a Mooney with a GFC500 autopilot. But the local flight school I teach at (amazingly) has GFC500s in every one of their airplanes. So I've flow with them in 172s, 182s, and a PA-28, including on 1 or 2-ish hour XC flights. Some of these airplanes lack the pitch trim servo, and manually managing trim is mildly annoying. But none of them have the yaw damper servo, and I can't detect anything about the way the airplane flies that I think would be improved with a yaw-sensing gyro, including flying in turbulence. My opinion is uninformed, however, having never actually flown with a GFC500 yaw damper in any airplane at all. I'd like to learn more.
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Ideas Needed for Instrument Panel Labels
Vance Harral replied to cliffy's topic in Avionics/Panel Discussion
For a professional look, I can strongly recommend engravers.net. Lots of choices, but I recommend black 0.020 Lexan with silver text. Matches vintage-era placards very nicely, plastic rather than metal as PT20J suggests. What I really like about the engravers.net guys is that they'll custom cut the placard to any shape you want, drill holes, etc. You just have to give them a detailed template. I send them a to-scale PDF with dimensions, and I get back exactly what I spec. Very inexpensive, too. -
Caution is appropriate, and a thorough pre-buy is always a good idea. But lack of ADS-B in 2022 is arguably less likely to be indicative of a poor maintenance attitude than other "deferrals". A number of aircraft owners simply don't want to be tracked, don't fly in rule airspace, and therefore don't need or want ADS-B. I'm not one of them, but I know some. I think those of us who like ADS-B and/or live in big metro areas, tend to forget there are still huge swaths of airspace where ADS-B isn't required even after the 2020 deadline. In general, it's not required in Class E airspace outside the lateral boundaries of Class B/C, up to 10K MSL. Quite a lot of country falls in that category. Not sure where the OP is buying his airplane, but if it's based out of, say, some small town in the midwest, the lack of ADS-B doesn't necessarily mean the current owner doesn't care for the airplane.
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Questions after my first familiarization flight
Vance Harral replied to Papa K's topic in Modern Mooney Discussion
Cowl flaps should be operated based on observed cylinder head temperature. It's not an "always open during this phase of flight, and always closed during that phase" thing. Your normally-aspirated Lycoming is generally fine at any cylinder head temperature between 250-400 degrees. Below 250 is too cool for the lead scavenging agent in the fuel to activate, and you're likely to get plug fouling. Above 400 starts to affect engine longevity. Halfway between those points is 325. Consider that a soft target (don't agonize over it), and open/close cowl flaps as needed to stay around the target. On a hot summer day, cowl flaps will need to stay open during the entire climb. After leveling off for cruise, it may take quite a while for CHTs to cool down below 350 or so. Don't close the cowl flaps before that happens. On a cold winter day, I still have the cowl flaps open for takeoff (checklist item and force of habit), but if I look at CHTs early in the climb and see them under 300, I'll close the cowl flaps while still climbing. I'm not always perfect at executing this strategy, and neither is anyone else. Fortunately, it's not an especially critical item, at least not in 4-cylinder Mooney models. -
Why is Elevator Control so Heavy?
Vance Harral replied to MBDiagMan's topic in Vintage Mooneys (pre-J models)
I think what you're really asking here is, "what's normal"? The replies to this are going to be model specific, because different models of Mooneys had different elevator pitch control systems: some have bungees, some have a counterweight, etc. Concentrate on replies specifically from other F model owners. In our 1976 M20F, the spring bungees incorporated into the pitch control system result in a stiff elevator feel, even when everything is properly assembled and lubricated. With the trim set to the takeoff position, I would estimate it takes nearly 20 lbs of pressure to hold the yoke either fully back or fully forward against the stops. That's the effect of the bungees. When I fly the airplane with two passengers in the front seat, and set the trim indicator about 1/2 inch further up than the marked takeoff setting (a very reasonable choice with no weight in the back seats), I wind up pulling about 10 lbs of force on the control wheel to get the nosewheel to unstick. Once the nose comes up, I relax that pressure, and the airplane climbs nicely at that trim setting. So if you're experiencing around 10lbs of force from time to time, I'd call that normal. If you're experiencing 20/30/more lbs of force, something is wrong. -
Just a data point for the OP: I've known Brian Pickerell for about 20 years, and the seller of this aircraft for about 3 years (he's an enthusiastic aviationist, has gone from zero hours to CFII in that period, and has over 400 hours in this particular Mooney). Both of them are personable, standup guys. That doesn't mean either/both of them might not have missed something, and you should still get an intensive PPI on any airplane you buy. But I promise you're not deliberately getting a lemon unloaded on you by shady characters.
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Your best bet is to discuss this with Bruce Chien, as others have indicated. You don't need to join another message board to do so, and in fact that's not really the best approach anyway, as he gets so many questions that his answers on those venues are understandably clipped. Suggest you contact him directly via http://www.aeromedicaldoc.com/ and offer to pay for an hour of his time as a consultant.
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Seeking CFI/CFII for Transition in Denver
Vance Harral replied to Hans in Denver's topic in General Mooney Talk
Paul's airplane is at KBJC, and he's not (yet) an instructor. I'd like to help, but I'm not really the right guy for this. I've got about 30 hours' dual given in the right seat of K models, but only giving instrument instruction, flight reviews, etc. to pilots who have already received transition training and have plenty of turbo Mooney time. My airplane is NA, and as much as I understand the principles of turbo engine management, I wouldn't trust transition training to any instructor who doesn't have significant left-seat turbo time. -
Centennial or Rocky Mountain airport CO
Vance Harral replied to Mark89114's topic in General Mooney Talk
The runway at KBDU is 4100' in good condition. Field elevation is about 5300'. Margins start to get a little thin in something like an Ovation at gross weight, but A/B/C/E/G/F/J models are fine, provided winds aren't squirrely... ... and that's really the only reason I don't recommend KBDU to newcomers. The wind can be funny there, being right in the shadow of the flatirons. Much of the time, winds are light out of the east at the surface, and there's nothing to hit off the end of runway 8, so risk factor is low. When the prevailing west wind kicks up enough to push to the surface, those unfamiliar will choose 26, which points right at the mountains. The issue isn't actually the mountains themselves, it's that the topography around there can generate a wicked downdraft just a bit west of the runway. The tow pilots I know there won't take off on 26 unless the particulars of the day and airplane they're flying will allow them to turn crosswind at or prior to the end of the pavement. -
Centennial or Rocky Mountain airport CO
Vance Harral replied to Mark89114's topic in General Mooney Talk
Another vote for KBJC instead of KAPA. Speaking as a local, I'd urge you to also consider uncontrolled options (KEIK, KLMO), but you won't get 24-hour FBO staffing there. Signature is the "established" FBO, at KBJC, but I've heard good things about new-kid-on-the-block Sheltair. No personal experience there, though. Note that KBJC has a self serve pump which is competitively priced with nearby uncontrolled airports. But any savings is probably eaten up by what the FBO will charge you if you don't purchase fuel. FBO fees and policies change frequently depending on who's working the desk, phases of the moon, etc. Strongly suggest you call a day or two before arrival and figure out which of Signature or Sheltair is offering the best deals for piston singles. -
What airport and flight school/flying club?
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Colorado - Looking at buying a Mooney, but never flown in one
Vance Harral replied to Icebrk34's topic in General Mooney Talk
@TheStig moved to Florida. But there are other Mooneyspacers in the area, including myself (M20F) at KLMO and @gsxrpilot (M20K) at KBJC. My airplane is the last year of the M20F. It's effectively an early-model M20J in the cockpit (electric gear and flaps, 6-pack panel, etc.), it just doesn't have the airframe speed mods that make the early model Js 10-15 knots faster. If you can't find an actual M20J to ride in, my airplane is a decent facsimile. I'm tied up through the end of the year, but would be happy to give you a ride shortly after the New Year if someone else doesn't before then. For the M20M, you probably do want to find a ride in a long-body model, and I don't have any inroads for you there. Hopefully someone else will step up and offer a ride. -
What Is That Thing On The Co-Pilots Yoke??
Vance Harral replied to GeneralT001's topic in General Mooney Talk
Fair question, and one of the things we checked when deciding to install. With the balls on the yoke and the compass up on the center post, the distance is large enough not to have any effect. No, I didn't do a full before/after compass swing. But before attaching, I moved the ball mounts from "far" away, up to the yokes, wiggled them around in the yoke area, and didn't see any visible movement of the wet compass. This is not an acid test, but no worse in practice than avionics shops which never re-swing the wet compass after installing new gizmos, even though it's technically required. Data point: I have a magnet of similar strength on my key ring, and I put the keys on the glare shield during preflight, which tends to wiggle the compass. I worry a (very) little bit about buggering the compass that way, but I confess I just do it anyway. That key ring magnet needs to be within about 12" of the wet compass to actually produce any visible movement. If I put it on the far edge of the glare shield, the field strength just isn't big enough to matter to the compass. Makes you appreciate how strong the "weak" magnetic field of the earth really is. -
What Is That Thing On The Co-Pilots Yoke??
Vance Harral replied to GeneralT001's topic in General Mooney Talk
Not until just now! -
What Is That Thing On The Co-Pilots Yoke??
Vance Harral replied to GeneralT001's topic in General Mooney Talk
That's a Nite-Ize "Steelie Ball" mount for phones/tablets. https://www.amazon.com/Nite-Ize-Original-Steelie-Magnetic/dp/B01JJP5JAW/. Note that this link is to the larger, more expensive size, designed for tablets. Don't confuse it with the smaller, less expensive size, designed for phones only. We have one of these mounts on each yoke in our airplane. It's far and away the best phone/tablet yoke mount I've found, for a couple of reasons. First, there's nothing faster than a magnetic mount for attach/de-attach. Just pop the device on/off the yoke in a half second. No clamps, no tabs to click in, etc; just on and off, immediately. Second, a ball mount allows you to swivel your phone/tablet around on the yoke. Very handy if you want to switch from portrait to landscape orientation, or just make a slight adjustment when the sun happens to hit an angle that causes glare and/or a blinding reflection. -
That sounds about right to me. Labor adds to the $700 kit cost if you're not your own A & P, but swapping injectors is not a labor-intensive job. Maybe a couple hours worst case (sometimes you need to go multiple rounds of swapping with GAMI to get the absolute best result). Call it $1000 all-in, and a 200 hour payback worst case. This is a theoretical argument that assumes one meticulously manages the mixture at all times. If you're a little lazier like most of us, and/or spend a lot of time flying around the pattern, doing IFR training, etc., you're not going to save the full 0.8gph during every hour of operation. Regardless of those quibbles, though, there is always going to be a break even point within a few years. Up to each pilot to decide if that's the best use of their dollars compared with additional training or other alternatives. Let's try not to confuse the original poster, who has a normally aspirated engine (as do I). Turbocharged Senecas and 252s have the option to run LOP in cruise while still maintaining "rated" cruise power (60%, 65%, 70%, 75%, whatever - take your pick based on desired engine longevity). One can simply push the throttle forward, increase manifold pressure, and maintain rated power up to the critical altitude of the turbo. That ability to maintain rated cruise power and run LOP without slowing down is attractive. If I had the privilege of operating a turbo'd bird, I'd likely fly LOP in cruise. At optimum cruise altitudes in a normally aspirated engine, however, it's a tougher sell. Running LOP and also making rated cruise power requires staying low, where additional drag is working against you. Climb up to optimum NA density altitudes of around 8K and you're likely below max rated cruise power even at the best power mixture. Going LOP there slows you down. Still a great tool in the tool bag for increasing range when needed. But a lot of us normally-aspirated drivers just can't stand to give up the knots it costs to get the benefit, even though that's an emotional argument that has little impact on real-world, door-to-door enroute times.
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If we're going to get into details, let's get it exactly correct. Balanced fuel flows across all cylinders increase engine smoothness at stoichiometric mixtures, and mixtures lean of stoichiometric. Producing the same amount of power under these conditions requires injecting the same amount of fuel, because fuel is the governing input to the combustion equation. Unequal amounts of fuel -> unequal amounts of power developed -> engine roughness. But unbalanced fuel flows across all cylinders in rich-of-peak operations have (almost) no effect on power developed, and therefore no effect on engine smoothness. The reason is that the excess fuel in a rich mixture is simply unused, and blows out the exhaust unburned. It doesn't matter whether you have "a little" more fuel than the stoichiometric ratio, or "a lot" more. The power developed is the same (well, aside from the effects of small differences in additional cooling, and the density of the material exiting the exhaust system, which explains the less-than-flat power/mixture graph on the rich side). If your point is that unbalanced fuel flows across cylinders can allow some cylinders to be ROP while others are LOP, sure, that's true. But that is not "best power", which is the point you are emphasizing: Best power in an aircraft cylinder is always rich of peak (100-200 degrees ROP for the typical Lycoming, see graph below). If the mixture crosses over into lean-of-peak operation, the cylinder is not running at best power. Furthermore, as the graph shows power decreases more quickly on the LOP side than on the ROP side. So in an engine with less than perfectly matched fuel flows, best power is achieved when one cylinder is around 150 degrees ROP, and all other cylinders are still ROP. Again, if any cylinder actually crosses into LOP operation - where fuel flow does affect the power developed - that is by definition not best power. LOP operations tend to produce plug that look nice when pulled for inspection and gapping. But let's be careful with the word "fouling", and distinguish cosmetics from actual mis-firing of the plug. As a primarily ROP-in-cruise flyer, I have zero problems with misbehaving spark plugs. This is almost certainly because I aggressively lean during low power ground operations, which is where essentially all plug-fouling-of-the-type-that-causes-misfire occurs. Barring very extreme cold weather operations, any power setting actually used in flight produces sufficient cylinder combustion chamber temperatures for the lead scavaging agents in the fuel to do their trick, and it's generally lead contamination that causes poor spark. Again, the plugs from a primarily-LOP-flown engine will tend to have just a hint of light brown residue on the plugs, while a primarily-ROP-flown engine will have a heavier, blacker residue. So LOP is "cleaner" for the plugs, no argument there. But not cleaner in a sense that actually matters. I'm not finding huge balls of lead down in the plug well when I pull my plugs for inspection and gapping, and I don't have problems with mis-firing plugs. Concur, no argument. If I had GAMI injectors, then instead of flying with one cylinder at 150-ish ROP and some of the other cylinders even richer, all the cylinders would operate right at 150-ish ROP at the best power setting. There would be no difference in the power developed or the speed I traveled at vs. without GAMIs, but fuel flow would be a few tenths of a GPH less.