0TreeLemur

After work today I changed the JPI EDM-900 pre-alarm setting for the CHT from 460 to 405 and took her up to see how that worked. I was hoping that the CHT bar chart would turn yellow like the EGT bar graph does. Nope. As I recall, the warning is a text string in the rolling window that said something like "CHT4=405F" in a blue font. Not a real attention grabber. Anything I can do or am I S.O.L.?

That's awesome! Thanks @Junkman! I'll work on getting that set. Having a visual warning will really help. Looking at my data, most flights before I started really watching it, CHT4 went over 410F, usually by a few degrees, seldom more. I put that limit into the Savvy Analysis online software, and having the ability to stop it from happening so often will hopefully maximize my engine life. With his ability to perform analytics on all those EDM data, plus the experience of matching damage histories with CHTs, when Mike Busch gives a limit I think there is nothing wrong with trying to do as he suggests and keep the CHT below 410F.

Here's the saga redoing the panel in our '67C. We used Cerecoting, which is a baked-on ceramic-like coating. Folks do it with firearms a lot.

Mike Busch says we should strive to keep the CHT in Lycomings below 410F. Looking at the programmable settings in the JPI 900 menu, I don't see a "warning" CHT setting. Of course the 500F redline setting is there. I wish we could set a warning level (e.g. 408) that would turn the CHT bar yellow and help show that the temp is getting high. Is there such a setting and I just missed it? I need to look at the manual- I don't think there is a warning setting. Anyone have any experience communicating with JPI? I've heard rumors that their attention can be difficult to obtain....

In a rolling dive? If I were in that situation "add afterburner" would not be the next line in my recipe book. Wow. Thanks for posting this @kmyfm20s

Today I flew to Aircraft Spruce East at FFC to buy some oil. I took this appropriately weird photo for Feb. 29, 2020, while waiting to depart FFC in our M20C. Lots of warbirds at that drome. I suppose in support of the film industry around Atlanta. This one seems to be a North American dressed up to look like a Japanese Kate torpedo bomber.

The barometric pressure in the southeast US has been really high lately. Today it was 30.40" with low density altitude, I was seeing 27.6" MP WOT on takeoff, the CHT on Cyl. #4 up to 411, with cowl flaps open and maintaining 100+ kts on climb out, despite the 13C air temperature. I reduced power to 26.5" MP, which brought the CHT on that jug back to 403 or so. The FF on the JPI900 indicates about 16 gph at takeoff power for the O-360 (carbureted) in our C model. The Mike Busch book "Engines" has saved me multi thousand $$ already- pretty good ROI. I'll follow what he says.

Mike Busch in "Engines" p. 85 wrote: "I'm convinced that if every piston-powered aircraft was equipped with a modern probe-per-cylinder digital engine monitor that set off alarms anytime any CHT rose above 390F for Continentals or 410F for Lycomings, cylinder head-to-barrel separation fatalities would become largely a thing of the past."

FAQ: REMOVING TANK SEALANT

You are correct, aerodynamics of spins are very messy. But, since we don't spin Mooney's intentionally , I'm not really thinking about the effect of forward-swept rudder on spin recovery. It is much easier to make he case that at high angle of attack (e.g. landing flare) a forward swept rudder will have more effective area per unit deflection and length than an aft-swept rudder because the forward sweep minimizes spanwise flow. That point is easy to make from geometric concerns, right? Any data on that?

The C wing is 174 ft2 for a 172 or 177RG, and yes, a different airfoil. The 172 is fixed gear with struts and fixed pitch, the SP model has the IO360 rated at180 HP. The 177 is retractable with no struts, and constant speed prop. but 200 HP. The C177 has a bit more empty weight, and about 100 lb more useful load than the the M20C. The POH cruise speed of the C177 at 7500 and 70% pwr is listed as 144 kts at 10 GPH. Our '67 M20C at 7500' does 143 kts at 10 GPH on 70% of 180 HP. The C177 with its 100 lb more UL isn't going to make me make another trip, I'm going to leave baggage at home. The 172SP at 124 kts and with fixed legs and struts hanging out isn't a fair fight, even though it has the same amount of aluminum in it. The data comparison in the paragraph above indicates to me that the drag of my M20C at the same airspeed requires 14 fewer horses to move essentially the same load through the air as a C177. That equates to less drag? Some of that reduced drag is airfoil, and some is cross-section? Which C model would you compare against a M20C? What model of C would be most similar head-to-head. ? Note, our M20C does have the lower cowl closure mod but not the 201 windshield.

Making a small cross-section fuselage with a high wing is possible only if the pilot's head protrudes through the upper wing surface into a blister (greenhouse). Data suggest that the interference drag created by the low wing configuration is significantly less than the additional drag of a larger x-section fuse due to pilot visibility requirements (M vs C) with equivalent O360.

FAQ: WHERE CAN I FLY TO LUNCH? Change the airport (KTCL) to your home drome (e.g. KWTF), then change the search radius if you want (200) NM?, and whether or not it must be on the airport (1) or not (0) Search here: http://www.fly2lunch.com/results.php?apt=KTCL&radius=200&onApt=1 Thanks to @flight2000 for the reminder.

Not in Central Florida, but good- Air Prop Specialists in Marianna, FL., which is in the panhandle. They will do the ECI on your plane while you wait. Free lunch at the city-run terminal. I think they charged me $185 last time they did it on our '67C.

Yes, this is an issue. It is why I stopped donating to Wikipedia- their editors can be maddeningly inflexible. If someone else who likes a good fight wants to "tag in" and carry on with this battle, I'd welcome it. Ideally, if I could find a perfect, irrefutable published source confirming that Big Al Mooney was correct, I'd put it in there and dare the troll to show is true colors or shut up. I thought I had done it with the Garrison article. Grrrr.

Yes, I know of that quote. The problem is this: If Al Mooney or I said it, it is opinion. If an independent "expert" confirms it in writing in widely available popular literature, it becomes fact. I kind of get it. I really thought that Garrison's article in Flying sealed it- but the "expert editor" seized on the statement by Garrison that aft sweep is bad. Therefore, forward sweep is good. Eh? Here's what Peter Garrison wrote in Flying in the April edition of 1995: "The loss of stabilizing authority of a swept tail is slightly offset by the increase in tail moment arm -- that is, the tail, by virtue of being swept, is slightly farther away from the center of gravity and so slightly more effective. But the increase in tail moment arm is proportionally very small and its benefit disappears beyond about 15 degrees of sweep. (Lift curve slope can be regained by increase the aspect ratio of the vertical surface, as Cessna did when it swept fins in 1960. Sweeping the tail is also detrimental to spin recovery. In a spin, air flows across the fin and rudder at a steep angle; with a strongly swept fin- the fins of single-engine Cessnas have 40 degrees of leading edge sweep, worthy of a transonic fighter-- the hinge line about which the rudder pivots is more nearly aligned with the flow, and the effectiveness of the rudder drops sharply. In fact, the swept forward fin that is a hallmark of Mooneys was originally intended to enhance the spine-recovery characteristics of Al Mooney's single-place Mite (which was to be an aerobatic airplane) by setting the rudder hinge line at something closer to a right angle to the airflow in a spin. What eventually became a styling feature began as a rather ingenious technical innovation." Who can read this and not confirm the assertion that forward sweep is good for rudder authority at high angle of attack? Anybody else on here ever edit Wikipedia? Anybody else want to insert or cite this quotation into the "Design" section of the M20 Wikipedia page and reassert the point?

In terms of FAQs I think of Qs like these: 0. What constitutes a pre-purchase inspection? 1. I'm considering buying a pre-J model Mooney. What are the gotcha's? 2. I'm considering buying a J or newer Mooney. What should I watch out for? 3. I just bought an pre-J Mooney, what should I consider doing first? 4. My tanks are leaking, what can I do? 5. What maintenance can I do as an owner on my Mooney? 6. Is Mooney transition training important? 7. I'm a new Mooney pilot and I'm having trouble slowing down. How? 8. Is the PC system worth keeping? 9. What is SB208? Why is it important? ...

No, I don't have Larry Ball's "Those Remarkable Mooneys", nor do I have Garrison's 1980 "The Complete Guide to Single Engine Mooneys". Garrison's article is unfortunately not definitive about the Mooney tail, so I suspect that his book isn't either. Do you know if Larry Ball talk about the tail design and the advantage of a swept-forward rudder at high angle of attack?

Thanks for the encouragement. I was inspired by Garrison's article to improve the "Design" aspect of the M20 page. With your help maybe we can get it done. If you can find that advertisement, that would be really cool to see and another bit of evidence. Oh- some interesting quotes, including at least one attributed to Al Mooney here: http://www.mooneyevents.com/quotes.htm

Those would be great topics for a FAQ section!

Sorry to have you waste so many words. My understanding is not the issue. My problem is that I have a troll editor who is resisting my attempts to incorporate this little gem of knowledge regarding the swept forward Mooney rudder into the M20 article on Wikipedia. He insists on a good 3rd party reference. The 1996 article from Flying by Garrison (?) that Skip referenced at the beginning of this thread is insufficient for this troll editor because Garrison wrote both that it matters, and that it maybe doesn't. That is the problem with requiring 3rd party verification from the lay press. What is needed is a good reference report or article saying that a forward swept rudder has more effectiveness at high angle of attack than a normally aft-swept rudder, using itty-bitty words, with no uncertainty. I could write dot products with fancy sketches all day, and that won't matter. Any written independent article that says exactly what we know will be most appreciated, so that I can edit the M20 wikipedia page to say this. I added it, including the reference to the 1996 Flying article, and he deleted it, because he is "experter" than me. Well, I'm not gonna give up that easy. Any help you can provide, ideally written in not too many big words or high level mathematical notation will be appreciated. Someone on the MooneyPilots.org or some such place said that there was an interview of Al Mooney from years ago where Al discussed all this. Anyone have a reference to that? Thanks.

There is a so-called "expert editor" that I'm having a disagreement with right now about the utility of minimizing spanwise flow with a forward swept rudder at high angle of attack. Any data or especially a publication that supports this notion would be helpful. No rush at all, this is a hobby project, but I would love to hear about anything you can find regarding the M20 tail. Thanks, Fred

Yesterday on an IFR practice flight from TCL to ANB, in cruise at 7000 ft, T=1C with a freezing level forecast to be at 8000 ft, I looked up from my scan to see this. I was flying through supercooled raindrops that were freezing even though the air temperature was above freezing. My request for lower was immediately approved, I took this photo in the descent. The wings looked just as bad as the windshield.

It does sound like it might be a treasure of design info. Please share with us all you can.

A select group of known users with editorial authority can identify threads or pieces thereof, edit for clarity, focus, and content, and move them into the FAQ. They should not be controversial, nor should they be editable by normal users. This work should be done offline and just posted when ready. Did you try that? Properly done it will be frictionless and controllable. I publish a lot. If your past experience went sideways it was not correctly designed and/or implemented.