Blue on Top

All y'all are funny and great at the same time . There is a difference between BEW (Basic Empty Weight) and BOW (Basic Operating Weight). BEW includes all unusable or undrainable fluids. BOW includes fluids and equipment in the normal operating state (engine oil at full; full O2, if planned on using; full TKS fluid, again if planned on using; charts/manuals/etc.; pilot, again if planned on using, etc.) O2 is probably not serviced until in Production Flight Test where it is actually verified that it works.

1. When they were first introduced people listened to all the hype (one-sided ... not telling the whole story). Yes, an 85% scale Starship (72% drag) will meet performance numbers when full size engines are ,used. 2. Although the Starship was originally intended to replace the King Air, it couldn't compete (for many, many reasons ... most of them performance related). King Airs are just efficient flying machines. There are good reasons that there aren't composite airplanes all over the place. They are heavy and expensive. Cirrus sells chute. BTW, good OEMs outdate their own airplanes every 8 years or so. 3. Beech had ODA then, before they went bankrupt and now under Textron Aviation. 4. There is no new airplane market because OEMs won't look for new cheese ... or at cost effective prices. The 70s market was ... well ... 50 years ago. Different times, different manufacturing cost structure and different labor costs. There are new airplane markets. 1B. The same is true for the new $$BB Uber Elevate market. Great idea, but no physics has been looked at. A helicopter that takes 150 HP takes 150 HP to operate - gas powered, electric powered, hydrogen powered, etc. Making the disc loading higher INCREASES noise and decreases efficiency. Go figure

Nothing new here. Al has been giving this talk for years (decades?) at the Western Soaring event in Tehachapi. Adverse yaw is trivial in the grand scheme of drag. I'm still looking for that rudderless, high thrust, multi-engine bird. The Citation X wing is designed similarly (30 years ago). It is very much a point designed airplane, ... then they went and added a winglet (no comment). @A64PilotCanards are terribly INEFFICIENT. One needs to look further than the surface of one portion of the balance equation. Yes, in a canard, both surfaces are lifting, but that is ignoring a lot of other downsides. The downwash off the canard affects only the inboard section of the main wing ... and each flight condition produces a different downwash. As a result, the main wing inboard section needs to be of variable incidence :)) ... while not changing the outboard section. All takeoff and landing performance is based on stall speed. Canards have higher stall speeds because the small wing (canard) is maximized at the expense of the main wing (which should not stall). Inboard DOWNload on the main wing of the Starship is near 1000 lbs. in cruise. CG loading is also much more difficult in a canard. There are a good reasons why the King Air is still in production and the Starships have been destroyed.

Bungees will only change (out of trim) forces and help stability ... stick free and stick fixed become closer to the same. Control of the aircraft will not change with bungees ... only the control surface stops will change the performance of the airplane. In addition, when the elevator down travel was increased, no new parts were made (some clearance modifications were made), which means that the gearing wasn't changed (majorly. minor gearing changes will happen due to a different (or in this case larger) portion of the sector is being used. The differential in the aileron system uses this type of geometry to make the up-going aileron travel more than the down-going aileron.

@cliffySome things will never be answered as much time (and many people) have passed. Here's a few points to ponder, but I have no definitive answers. 1. The only reason that I know to increase the down elevator throw of an airplane is spin recovery. 2. Flight characteristics will not change if the flight control system gearing did not change. It looks like travel was increased by changing the length of the push-pull rods (which may explain the trim change(s) 3. Deflection changes in '69 are noted in the S&MMs for the series (attached). 4. I also noted a Service Instruction "Mooney S. I. M20-44" (also attached) which appears to be for both mis-installed push-pull tubes in the tail section ... and to make clearance for larger travels. 5. Here's an educated guess as to "why?" There was probably a spin accident that occurred, but the exact CG and loading were not known. The FAA probably asked Mooney to run some spin testing at aft CG. I am not sure if Mooney did spin testing for the original M20E since the airplane, weights and CG envelopes were the same as the M20C. Something was probably found (slow recovery ... 1-turn spin has to recover in 1 additional turn), and Mooney and the FAA agreed to the elevator travel change. The FAA probably didn't have enough evidence to bring out an AD, and Mooney probably didn't want to put something out that said their airplanes could have an issue. Blue on Top, Ron S&MM Elevator.pdf SIM20-44A.pdf

@carusoam Please tell me more. I thought the wing was twisted through the M20G and the M20J wing was "untwisted" to gain speed. Warning! WARNING!! Selfless plug coming ... I, "Blue on Top LLC", is here to be your mod/STC/improvement shop

Canards are much LESS efficient than conventional tails. The Beech Starship/King Air is a great example. Why? Downwash off the canard changes the wing local angle of attack ... and is different for every flight condition. The main wing angle of incidence would need to be variable ... but that would mess up the outboard wing outside of the canard downwash. With a conventional airplane the whole tail is the the downwash of the wing and can be changed accordingly. In addition, a canard maximizes efficiency of a small surface (the canard) at the expense of the efficiency of the much, larger main wing. In cruise of the Starship, the inboard main wing is pushing DOWN with a force of ~1000 lbs. In addition, the pusher propellers of the Starship need 5 sectors of different blade pitch to be more efficient ... hence the weed wacker sound when they fly over ... with exhaust going through them.

1) Not all airplanes have a symmetrical vertical fin airfoil. Some even have the fin offset to counter torque. 2) Symmetric horizontal stabilizers are to lower part count; they can be left or right (same with elevators). Even if the stabilizers have camber, the elevators may not (again to save part count/tooling). 3) The Stearman tail is VERY heavy (probably in the range of 400 lbs. on the tail wheel (it needs lift to offset its weight). Ron

I'll do my best, but this might take further explanations. So increasing down elevator travel very much supports stall/spin recovery. And @cliffywas going down the right path ... until he cogitated a little too much. Here's an aspect of CG where many people falter. After several unrecoverable spins (and fatalities) aerobatic pilots are beginning to understand this, too. CG is not just CG when discussing spin recovery. I'll try to put this into a good example (which I am not good at). The M20C and M20E have the same CG envelope, so what could be different? Mass (or weight) distribution is different. I'll go further with the example than the real airplanes. In other words, I'm making up numbers here. Say an owner installed a new engine that was 100 lbs. heavier than the old one, and it was 4' in front of the CG. To keep the CG in the same position, he adds a 25 lbs. lead weight in the tail, 16' aft of the CG. Both CG moments are 400 ft.*lbs., and they offset each other. CG is in the same location. BUT ... Izz (the moment of inertia about the vertical axis) has gone up dramatically. In other words, in a spin, the airplane will want to spin faster AND flatter, but the aerodynamic recovery forces have not changed. Spin dynamics and aerodynamics are very, very, very complicated. Hope this helps ... as a beginning.

@Cyril Gibb Probably not publicly, but you can ask Mooney. I wish I could tell you more.

@Andy95W I would estimate both. Al was an avid reader/learner and designed his first airplane professionally at the age of 19. All of his work at Culver with elliptical wings and leading edge slots culminated in the M20 wing design. Of course this is with his brother Art adding in the manufacturing portion. The Al Mooney M20 wing (the wood wing) development is documented in a very interesting Mooney document. The wing has a very close to perfect elliptical lift distribution. Preliminary design of the M20 was actually completed in Wichita. Al and Art knew their stuff

PS2 Swept tails are heavier. PS3 Remember I said everything in design is a tradeoff? The aerodynamic center of Mooney surfaces are closer to the CG (shorter arm) than airplanes that have swept (aft) tail surfaces. PS4 Yes, the straight leading edges were an ART Mooney input for easier manufacturing (and less wasted material).

Wow! It's the only word I can say after reading this whole thread. Everyone is close, but ... that only works for horseshoes and hand grenades (like we used to say in grade school). All y'all nailed the strutted, high wing Cessnas and the Lark, so let's get to the Mooney tail. Note: The Mooney tail aerodynamics visualized my be my last "The Mooney Flyer" article for a while ... hopefully in the May issue. Let's go ... Rule #1 - EVERYTHING in design is a tradeoff. Forget the leading and trailing edge sweep angles as they really don't matter. What really matters (aerodynamically) is the 25% chord line. Since Mooney surfaces are all straight tapered, measure 25% aft from the leading edge at the root and at the tip and connect those points. This is the sweep that the airflow cares about. ALL 3 Mooney surfaces (wing, horizontal and vertical) are forward swept. Now we'll look at the stabilizing surfaces. The horizontal doesn't change sweep with a change in aircraft AOA, but it does change local AOA. As the wing (aircraft) AOA increases, so does the local horizontal AOA due to an increase in the wing downwash. This AOA on the tail is further increased with flaps. A couple notes here: 1) downwash increases as wing lift increases and 2) remember that the horizontal is an upside down airfoil that creates a down force. Now to the main topic. The Mooney vertical surface is more effective as aircraft AOA increases because the 25% chord line is getting closer to perpendicular to the airflow (noting that downwash lessens this effect). This allows the tail to be relatively smaller. Tails are designed for the low airspeed conditions ... there's lots of yawing moment available at higher speeds. And now the kicker ... The rudder hinge line is actually more forward swept than the 25% chord line. Why does this matter? Mother Nature (airflow) wants to take the easiest path possible. If the vertical surface is aft swept (most modern airplanes), when the rudder is deflected, the air has a tendency to travel up the hinge line (easier) than going around the deflected surface (harder). With a Mooney, the air can't do this as easily. In other words (let's look at the left side of the vertical surface with a left rudder deflection - aero people call this the pressure side). Air doesn't want to go up the hinge line because it also has to go forward at the same time. Nor does it want to go down the hinge line as this is INTO a higher pressure area. As a result, it has a tendency to travel straight backwards around the deflected rudder. This is also why gap seals are more important in Mooney aircraft. ,,, and now you know the rest of the story. Blue on Top, Ron PS. Questions are welcome ... I'll learn, too.

I'll get back to all y'all this weekend. I had to post something to be able to follow the topic This is soooooo exciting! Sun-N-Fun is just around the corner, too!

Developing a product in this area. There are sooooooo many freakin' Mooney part numbers over the changes in models and years. I'm trying to get my head and hands wrapped around it. The main reason for my post is to allow me to follow the thread, but expect great improvements (usefulness, quality and price) shortly.

1) Engine weight 100 lbs. over advertised. 2) Cooling issues never fully resolved. 3) Engine TBR (no overhaul) is short. 5) Gear box TBR (no overhaul) is half of short. 6) Little to no help from Technify (including no interface drawings or models). 7) No help from Continental. 8) Base engine/FADEC is the only certificated portion - no accessories: alternator, radiators (2), oils cooler, thermostats, etc. 9) Only one propeller was approved as it has to be low inertia (light) but strong enough to take the power pulses. With that said, it ran flawlessly for 175 flight test hours. Thrust was never validated.

One. Al (and Art) left Mooney the day the M20A received the PC (production certificate ... on the wood wing). Seems the financiers were talking one night about how "cheap" Engineering was. Al took offense to the words. A couple years later, Al was asked to return to metalize the M20, but he refused. The LASA-60 above came out in 1959. Al wasn't at Mooney-Kerrville very long. The M-18 (and M-19) were designed and first produced in Wichita ... and the M20 preliminary design was also done in Wichita. There is a great Mooney design philosophy article over in an MS "Mooney Ads" thread. If Mooney International were smart, they would read and understand those words.

If all y'all get Kitplanes (or more appropriately Kitplanes Weekly via email), there is an article about another Al Mooney airplane, the LASA-60. Seems a gentleman found one of them and put a Chevy 383 stroker engine in it. He's now looking to part out the airplane and engine. I think the article says he has a potential buyer for the engine but is looking for an airframe buyer. I have a picture of an LASA=60 with the original Mooney logo on the tail (and the tail of a Mooney aircraft backed up to it. https://www.kitplanes.com/powering-a-mystery/ PS. All called this his M-22, his 22nd design.

Diesel engines are also turbocharged, so they maintain rated horsepower to a higher altitude. Climb is all excess Hp/weight.

MooneySpace is sooooooo much cooler than BeechTalk. I better stop there , but I'm running our of emotions here. I'm just so emotional, Baby. What an a terrible, conflicted person I am - a Type A, emotional enginerd. Can it get any worse?

In 50 years, when I am 106, they will have perfected and stopped the aging process. I am living forever. So, you old men, have your wheel chair race around the fully-electric Mooney on the ramp so that -a- has time to change the flags from green to checkered. Then get the he// out of the way because I'm starting up my electric Mooney and taking off!

So very rough numbers (so I can do the math ), The engines on a 337 are 160kW each. We'll say it's a very good Lithium-ion battery at 160 Wh/kg. Each hour of flight for each motor requires 1000 kg (2,200 lbs.) of batteries. This assumes that the batteries can be used to 100% capacity (65-70% is more realistic). In the end, a flight of 4 hours on a C337 will require 17,600 lbs. of batteries ... at 100% capacity. Not practical ... yet. Fuel cells need to get less expensive.

Yes! And they are doing the right things! They have replaced one of the engines with an electric motor and calling it "hybrid". That is kind of misleading as both propulsion devices are not outputting the same power. (note: I can't believe that I am going to say this ... especially to Erik of all people) But do the math. Very good Lithium-ion battery energy density is slightly above 150Wh/kg. For both propulsive devices to be outputting the same power all the time, the gross weight would be so high that the airplane couldn't get airborne. Check out Pearl Harbor Aviation Museum. They did an hour-long webinar on 1/29/21 on this vehicle. Wonderful presentation. Yes, they flew from LA to SF with this hybrid ... again, do the math for how much the electric motor was contributing ... and when. PHAM also did a webinar this past Friday (2/12) on a hydrogen fuel cell (ignore the costs) airplane. Both are cool webinars to watch ... with the reality filters on. So, why do I say they are doing the right things? They are getting all the other bugs worked out before (if and when) the solution to the energy density equation comes along. Because of centerline thrust, they don't have to deal with assymetric thrust when a propulsive device quits (distribution is much, much easier). They are dealing with motor cooling (Cessna already did the engine cooling portion). Motor power is NOT the issue. Even at 90-95% efficiency, cooling is. More than my 2 cents, but this excites me. =Ron

PS. The M20 is faster than the Velocity V-Twin ... with slightly less horsepower.

Diamond dumped the Thielert/Technify/Continental diesel engine when they started having problems. They designed their own series of Austro engines that they use in their airplanes now. Centerline thrust has its advantages ... and disadvantages. I personally like the configuration and modern CFD programs can handle the airflow much better today than when the 337 was designed. Google "Cessna XMC", 1014 or 1034, one of the cooler airplanes in my opinion. The twin canard is the Velocity V-Twin. Don't get me started on canards. Despite popular belief, canards are not efficient ... ask Beech. If they were, King Air would have been out of production decades ago ... it's still a cash cow for Textron (the larger ones). A Mooney philosophy 337 would be a very cool looking airplane. You got me thinking way, way too much! Thanks