Lood

On what grounds is the MTOW of a specific airplane calculated or determined? A friend of mine brought this up and it got me wondering. He flies an M20E and seeing that we share the same engine and wing, wanted know why the F has a higher gross weight? In turn, I would like to know how the later model M20J's had their gross weight increased to 2900lbs? Apart from the aerodynamic improvements, the J is basically the same airplane as the F in terms of power, wing, fuselage, etc. The question that arises here is, if the F can fly at 2740lbs, why can't the E do the same and if the J can fly at 2900lbs, why can the F do that as well? We don't have any intention to overload, or even try this out, but would just like to know out of interest.

I once drained my tank in order to make a calibrated dip stick and the tank actually took 34 gals when I refilled it. Below is the reply from my AME: "Good question. The 64 gallons is all useable fuel. The unusable is 15 lbs on your F model which would be in addition to the 64 gallons. In other words the tank capacity is 34,5 gallons." This makes sense in my case, but if I only fill with 64 gals, is the 15.0 lbs unusable still in effect, IAW, do I now only have 62 gals usable?

Just fill your tank and let it stand over night. Dip it the next morning and see how much fuel is gone. Then do the maths and decide how much you're going to loose in anyway. My managed and lived with my seeping left tank for almost 5 years, but now, depending on its level, it's leaking at a rate of about 5 gals every 3 - 4 days, so it's time to bite the bullet. I had the right tank resealed earlier this year and it gives me immense pleasure to always find its fuel level where I left it - even after weeks.

I am under the impression that my '67 F has all its 64 gal of fuel to use. Someone else differed with me and referred to the FAA type certificate data sheet for the M20 series and specifically the F and J models. According to that document, 15.0 lbs of fuel in these airplanes are not useable. I just can't lay my finger on it quickly, but I am very sure that I read somewhere that my Mooney didn't have any unusable fuel and is able to burn all 64 gals. I scanned through my POH, but nowhere does it mention anything with regards to unusable fuel, only that it carries 64 gal. Can anyone give me the correct version, please?

Same here. I stand to be corrected, but if I recall correctly, my CHT's dropped by almost 20 deg. I didn't gain any speed though.

Here in SA, we don't have flight following. I only file when going into a controlled airport and when I fly my family on long distance cross country trips.

I wash only when really necessary using a bucket, very soft broom and micro fiber cloths. I like Mequiars' products and I wax and polish about once a year. Using the bucket method, it is actually amazing to see how little water is needed to wash an airplane.

075/085 and 095/105 when it's really hot.

I'd just like to confirm: Seeing that the JPI930 is certified to use as a primary indicator, is the original factory probe still required on #3 or not? My thoughts were that if the stock gauges on the panel may be removed when fitting a JPI930, what use is there to still keep the original probe on the cylinder?

That's the interesting part Byron. I have also downloaded quite a couple of nice-to-have apps since I got my iPhone, just to discover that my trusty old G296 cam do it all. Many might even be easier to do on the Garmin in flight.

Well, it seems I'm lucky. Got almost 70 hours on my IO360A1A and all temps are rather cool. On a return flight last Saturday, the CHT's rose the highest since stabilizing at around 15 hours - to a max of 347 deg. OAT was 86 deg F. Normally, the CHT's are around 300 deg with #4 always being between 320 - 330 deg. Oil consumption has just about settled and since the last top up to 7 on the dipstick, during the 50 hour oil change, I have actually flown 16 hours and the level is now down to 6 on the dipstick. Most seems to have been blown out the breather though, looking at my F's belly. The level has been sitting around 6 for at least the last 4 hours and it seems that I will only have to top up for a long flight. I rather well informed person reckoned that if an engine hasn't settled after 25 hours, the break in might not have been successful.

400 deg be it then, but I'll continue not to let any CHT on my engine come close to 380 deg.

Here's a data sheet of the first flight where I noticed it. However, looking at the actual data, it doesn't seem to be as bad as shown on the bar graph of the JPI. I'll check all the possibilities on the intake side. I sure hope the exhaust valve spring possibility is incorrect - this engine has done only about 65 hrs since an extremely expensive overhaul. Engine Data.pdf

Lately, I've noticed that the #2 EGT is much higher that the other three when my engine is idling. I always lean aggressively for all ground operations, but this doesn't seems to make a difference. As soon as I increase the RPM during the run up, all EGT's level out, like normal and during all flight operations, all is normal. When I close the throttle on landing, #2 goes higher again. Anybody have an Idea where I can start looking?

I always turn the pump on during all take off's and landings. Been doing it for the past 4 plus years and over 300 hrs and never had a problem. I've had to replace the on/off switch on the panel though.

Double post.

Relax guys, everybody flies his or her airplane whichever way they like. Be it whatever type or model and everybody will defend his or her method with their own explanation, to be the best. Although I don't have any PIC experience on 231's, I was just commenting on the original post, because I know that it's SOP to have cylinder work done somewhere along the way before TBO on most Continentals - also true for the IO360 used in the 231, but in my friends' case, this never happened. I also know that no two engines of the same model react the same, despite being treated exactly similar. That's seen all the time on twins. Why didn't he just buy a J? Well, I guess because he could afford to buy an almost brand new 231 back in '82 and fly it like a J for the following 25 years.

A friend of mine bought a 1982 model 231 with 200 hrs total time. He flew it for 25 years before the engine was TIMEX, or actually 50 hours before and replaced with a factory reman. His engine was never opened during this 25 years and I'm sure it must be due to the manner in which he flies. On take off, he would never go higher than 35", climb at 30" and he always cruises at 26" in the normal non-turbo levels of 10k feet and below. At this power setting, he gets around 165 kt burning only 9.5 gal. It is my opinion that his engine never really worked hard and it lasted its lifetime - cylinders and all.

Also only use flaps on shorter fields, if there are obstacles and when heavy. Agree that the transition is smoother without flaps and the initial climb out better.

You'll be fine with the take off and everything. Just expect to see a rather poor ROC when it's hot AND if you're heavy at the same time. My '67F climbed out of Upington here in SA at about 150 - 200 ft/min - fully loaded. Upington is not very high, but it does get extremely hot there in summer.

Quite often, some of the home builders are looking for a prop for their project.

If you're landing at a high altitude airport in a normally aspirated Mooney, your cruising altitude will not be much higher than the airport itself . So, you won't need a lot richer mixture, if any, to be ready for a go-around. I normally cruise at around FL085/095, 75 deg ROP. This leaves all my EGT's in the 1360 deg region. My home field is at 4000 feet and normally, two turns on the mixture once at circuit altitude puts my EGT's back at around 1300 deg, which is adequate for a go around. Whenever I descend from FL105 to a low level airport, for instance, I simply reverse the leaning process. I keep an eye on the JPI and just keep the EGT's at around 1350 deg by enriching the mixture as I descend.

Agree with the target EGT method - mine is 1250 deg. Also, don't attempt such take off fully loaded or when it's very hot and make sure you have enough runway and no excessive high ground directly in your climb path. BTW, what are you flying?

I've also read and actually seen the start procedure with the mixture in idle cut off. I tried it a couple of times, but then my engine takes forever before it starts.

The replacement alternators from Plane Power are 70 amp IIRC.