Shadrach

Quote: 201er Very interesting response. I'm going to have to read those articles and give this some more thought. Does this mean that running 2700RPM at higher altitude is less bad than cruising 2700RPM down low (noise, engine wear, oil burn, etc)? However, I think you missed part of the oversquare point for high altitude and lower MP recommendations by POH. It would have been my guess that if 27"/2200RPM is allowed at sea level, that you would be good to use WOT above any altitude yielding 27" MP or less. However, if you look at the 4,000' performance table I posted, you'll see that although 26.2" MP are available (2400RPM column), a maximum of 24.4" is recommended for 2200RPM. This yields 62% power. There is clearly some kind of purposeful intent her rather than providing a 65% setting and whatever MP between 24.4" and 26.2" that would provide it. Also, they did not provide a 26.2" MP power setting for 2200RPM even though it probably would be available as well. Based on the table it doesn't seem that 2200RPM is an inefficient prop setting at 4000ft. In fact the opposite. 2400RPM and 23.3" yield 65% power, 9.2gph, and 152ktas. 2200RPM and 24.4" yield 62% power, 8.5gph, and 148ktas. My guess is that at 2200RPM and 25" you could get about 8.7gph and 150ktas. For these reasons, except if oversquare is the culprit, I cannot understand why the POH does not provide a 65% or full throttle power setting at 2200RPM at 4000ft as just one example.

The original airframe was certed without PC. The wing has adequate dihedral to make for a pretty stable platform in its own right. I cannot imagine any logical reason to remove or permanently disable the system unless it was being replaced with a modern AP.

A neutral density filter can be had for about $20 depending on application. I've seen folk have good luck with an ND2. YMMV.

Quote: AustinPynes I may just try to take one plate off and do a repair to get my feet wet. that is the only place I see past leaks at.

I have been into my tanks twice and my take is the following: 1) Polygone stripper works, it does not work fast, it does not work easily, it does not even work well... but it does work. 2) A low profile handleless Semco Dispensing Gun will run circles around a "can and brush" when it comes to quickly and accurately laying sealant. I got a new one on E-bay for $35, but I was lucky. They can be had fro under $200 used. Keep a brush handy for some of the detail work. 3) Flamemaster semkits work well. Use is CS 3204 B2 for fillet seams in the tank. Use CS 3330 B2 for access panels. A sloshing compound was used by the factory, I used PR-1005-L, some feel that the sloshing step is unnecessary. 4) No offense to José , but advising people that access panel sealant is "non bonding" and suggesting that integral tank sealant is a better option for sealing access panels is not just lousy advice, it borders on sadistic if the tanks ever need to be opened again. Removing the access panels when they are merely sealed with the "non bonding" sealant is a job. You could stand on the top panels with no screws in place and they would still not give way. 5) There's a reason why Mooney put mil-specs #s in the MX manual, all of the materials I've listed meet those mil-specs or are superseded by those mil-specs.

Quote: jlunseth Now I'll have to go look it up. It seems to me it was "Flying High Performance Singles and Twins" by John Eckalbar.

Quote: AustinPynes Now if I can just get a mechanic to call me back. It must be great business for A&Ps these days. One never calls me back even though he was a personal friend referral and I have emailed and left a VM. Another I have to call to talk to him as he will never call me. Seems the only ones that call back are farther away. Are A&Ps so busy they are pushing off work? Must be nice to have so much work you call back who sounds accomodating. Maybe it is me and I sound like a jerk in my emails and VMs. I will have to ask someone to review my messages. Cant be my breath as I havent met them yet.

Quote: Hank -For your last question, it seems that down low, WOT/2000 is rather similar to cruising on the interstate at 75 mph in 3rd gear instead of in 5th . . .

Quote: 201er I don't understand why a greater condition of being oversquared is permitted at sea level and higher power but not at higher altitude and lower power? There have been many times in cruise where I wanted to begin a descent leaving throttle full and simply pulling back the prop to reduce drag, but decided to bring the power back to the maximum POH applicable MP for that lower RPM setting. Is this really necessary?

Quote: jlunseth At higher altitudes, props generally become less efficient at lower rpm's. What you are most likely seeing in your POH are higher RPM settings at higher altitudes, required in order to produce a higher BHP. And that's because the prop is more efficient at the higher RPM at that altitude.

If the prop hub is leaking you will see grease stains on the face (back) of the prop propigating from the hub. This often happens when a mechanic or owner who doesn't now any better over-greases the prop (many still beleive that grease should be pumped until dirty grease is pushed out of the opposing zerk; this is wrong.). I think that a prop o-ring is unlikey to be the issue, unless it was damaged, reused, or forgotten (would be pretty messy). My guess is that it is the crank seal, which is not a real big deal replace. While I prefer the "stretch seal" that stretches over the prop flange, split seal can be installed without removing the prop. I installed a split in 2006 and have had no trouble with it. Before you replace the seal, make sure that the breather is open. A R&R'd crank seal will just leak again if the crank case is pressurized.

The biggest issue with taking a Mooney into a grass field is the lower gear doors on models so equipped. Those of you who say that they "were not designed for it" must have some clairvoyant ability to communicate with the late great Al mooney himself as I see no reason or great risk with landing on grass. Nor does my POH make any recommendation of it not being recommended. I regularly take my M20F in and out of and 1800ft turf strip in fair (undulating with clumpy crab grass) condition. It's a non-issue. The prop has 9" of clearance, maybe ~6" if the suspension is compressed. If you're encountering those kind of holes, then it's not a grass strip landing, it's bush work... Being that the rocket has the lower main gear doors, you don't want to land at a place where the grass is more than ~4" high, because you will have to clean off grass stains. The moral of this story is think about what you're doing before you do it. Make sure that the field doesn't have holes the size of Dallas. A Mooney is just fine on grass as the gear system is far hardier than their lesser brethren which folks take into and out off grass without thinking about it.

Quote: carusoam EB, My simple Garmin portable can be programmed for height above airport and distance away. No inflight calculations required. I think my set points are 400fpm, 1,000ft above, 3 miles out. My retro IFR GPS can set a descent angle (requires inflight calculation, I can't find a usefulness for this feature). Garmin allows me to arrive at TPA a few miles out, in order to slow to proper speeds. There are two other details that are helpful in this department. There is a vertical timer that tells how much time is left before the nose over. There is also a glide slope line that indicates if you are ahead or behind schedule. Like JL points out above, variations in density, power output and speed will make it near impossible to set a vertical velocity and keep it there. In VMC, you want to be looking outside, and not overly focused on the vertical speed. In the past I did the calculations for 3 miles per minute and tried to maintain VV. Conservative alt adjustments for engine failure. The end result was excessive speed in the traffic pattern. Gps vertical guidance is an excellent aid to balance safety and efficiency while descending with maximum forward velocity. Best regards, -a-

I use 3 miles per minute and ~1000FPM +/- 500 in descent depending on conditions and whether I'm alone (I don't mind clearing my ears repeatedly in descent but I'm mindful that passengers might.). I will reduce power to manage airspeed if necessary depending on conditions. I have no concerns about descending just under redline (~170kts), especially in the glass smooth evening air. I use the GPS descent profile function to make small adjustments.

I've not done a lot in the way of climb testing for 2 reasons. 1) In my anecdotal experience, the actual change in climb rate is not that dramatic (<200fpm) from 90 to 120mph. 2) I've never felt at a loss for climb performance. It'd be nice to have more, but I've never felt that I've needed more. I'm sure that if I was based out of Denver I'd feel differently. Unless I'm at or near MGW, which is rare (useful of 1059lbs, I'm typically 400-500lbs under MGW), 120mph almost always yields 1000+fpm at DAs under 3000ft and provides good cooling, visibility and forward speed. I look forward to reading more as your research and analysis continues... Also, I would not put tremendous stock in that lycoming graph. AFAIK, It is conceptual in nature and not engine specific.

Hi Norman, Being that you're doing your thesis, I would like to see more about how you're using SFC relating to mixture, rather than just taking Gami's estimate. I believe that the lowest BSFCs occur at fuel air ratios significantly lower than would be utilized at 25LOP (more in the range of ~35-65LOP, engine dependent). Moreover, Gami may or may not have been taking airframe efficiency into consideration when they came up with that number (I've personally don't recall 25LOP given as a "best SFC target, excepting for in this thread.). I don't believe that the power level that generates the lowest BSFC in a specific engine necessarily correlates to the most efficient power setting for a given airframe (discussion limited to normally aspirated engines). I think that you already understand this and it will be a significant part of your thesis. However, In addition to flat plate area, I'd like to see how you're accounting for the increase in induced drag that can result from lower IASs at the reduced power levels being used to attain the lowest SFC. It seems to me that those values would change with altitude and from airframe to airframe. Thanks! P.S. Do you still want the climb table from my M20F POH, or are you only wanting M20J info?

If your boost pump is not holding pressure, it can create "slack" in between the engine driven and electric pumps. If it is hot enough, the fuel will bubble (read boil) during the pressure drop, causing your engine to burp. Do you climb with the aux pump on? If the unit is a Dukes pump and you're thinking of sending it out, I must recommend Russell Romney/D&G Supply. I had my pump IRANd by D&G last year and they were fast, professional and communicative with competitive pricing. http://www.dgsupply.com/

Quote: Hank The higher I cruise, the closer to peak I run. On descent, I maintain cruise EGT [more or less] and cruise MP [more or less]. That ends us being lots of tweaks to those two levers. But then, I like having the quadrant rather than the push/pull/twist knobs.

I'm a LOPer and I do the following. It is not Gami or APS's method, but my own. YMMV... I enrichen in descent to keep the combustion event out of the exhaust (you'll see an EGT spike when this happens) as the mixture gets leaner in the thicker air. When approaching pattern altitude I'll set the EGT to the target take off target ~EGT or a little less if I'm still high. Perfect set up for a go around regardless of DA. Never had to use it thankfully.

Quote: jlunseth Speaking of distractions and loss of focus, I had a doozy the other night. I was coming in for a landing at a small rural airfield in western MN that was unfamiliar. It was a night landing and a short field, so I was working hard to keep the airspeed under control. At the "fence" and in the dark, I saw the silhouette of a tree line running perpendicular to the runway and not that far away, and the tree tops were above me. I have landed at a number of airports where there seems to be one tree sticking up right on the approach path to the runway, and I was distracted, looking for trees, when I suddenly realize I have lost track of my approach speed, and it is around 65 and falling, about 50 feet off the ground. That is "imminent stall" speed in my aircraft. I figured out what was going on, applied power, and made a safe landing. But I think this cured my of night approaches at unfamiliar small rural airports.

Randy, If you're going to continue to post as me , than I want the keys to that $%^#ing Rocket!

Quote: KLRDMD I simply don't see a reason for the Rocket to be smug when you fully analyze the situation.

Quote: KLRDMD I simply don't see a reason for the Rocket to be smug when you fully analyze the situation.

Norman, I'm happy to do that for you, but my POH is for a 67F model. I only referred to it to illustrate the lack of accuracy in the factory manuals back in the day. If you still think it would be of use let me know.

I'll concede Beeches and Mooneys, but single engine Cessnas are complete pieces of $h!t!!!...