Flight Ops

Engine Power Settings For Climb and
The Myth of Climbing At Reduced Power


 

Ed. Note: In the August issue, we took a real world look at the plusses and minuses of the M20C. The C model is a great airplane, but as we discussed, it is not the perfect airplane. This month, lets take a look at the 200 horsepower, Lycoming 10-360 powered M2OE. How does it compare to the M2OC? Does the extra 20 horsepower of the E model really make much of a difference? Is fuel injection really better than a carburetor? How much faster is an E model than a C model in the real world? The article will contain these answers along with my overall impressions after flying an excellent 1964 model M20E loaned to MAPA by Jimmy Garrison and David McGee at All American Aircraft and Dennis Bernhard at Lone Star Aviation here in San Antonio, Texas.

In our continuing evaluation of the airplanes owned and operated by MAPA members, the M20E was next in line for flight testing. Our goal was to find a stock E model and perform the exact flight profile as we did for the C model in the August issue. Not only would this give us a good feel for the performance capabilities of the M2OE, it would also give us a great comparison with the C model to see just how much of a performance difference exists between the two airplanes. And after finally learning how to operate the mechanical landing gear in the C model for the August issue, we were eager to fly an E model with that infamous "Johnson bar".

Note the aerodynamic differences in the cowling designs between the M20E (left) and the M20C (right). Neither one is very good.
Our first challenge was to find a totally stock E model to fly. We were in luck. Just across the street from our office here in San Antonio is All American Aircraft, one of the premier pre-owned Mooney dealers in the country. They just happened to have a superb '64E model on the showroom floor. N6966U, serial number 326, was taken in by the factory service center here in San Antonio, Lone Star Aviation, and transformed from an airplane with lots of problems into one in almost as good condition as when it left the factory in Kerrville some 36 years ago. All American was selling the airplane for Lone Star and had already found a buyer at the time of our evaluation flight.

The front end of the M20E showing the oversized inlet area for cooling air, induction air filter, and the small "ram air" door just above the induction air filter.

Lone Star Aviation had done a lot of work on 66U. They had the engine overhauled, repaired major corrosion in the tailcone, tail and flaps, resealed the fuel tanks, replaced the brake discs, complied with service bulletin M20-208 (corrosion in the fuselage frame) and had the airplane repainted. The results of all this work is what you see here --an early M2OE in superb condition.

N6966 Uniform had only 3184 hours on the airframe and 20 hours on the newly overhauled engine when we flew it. The airplane was in great mechanical condition. The only real squawks I could find were a cabin door that was almost impossible to close from the inside (the latch needed adjusting) and a tachometer that read 100 RPM low (I always use a digital strobe tach to set prop RPM when doing these flight tests-- mechanical tachs are notoriously inaccurate). For an airplane 36 years old, that is a very short squawk list indeed.

Let's go flying! As you walk up to the M2015 on the ramp, it's hard to tell it from the M20C. Firewall aft, these airplanes are identical. About the only way to tell the two apart is in the appearance of the lower cowling. The carbureted C model has a square "chin" protruding from the lower cowling that houses the induction air filter The E model lacks this chin, although the filter for the induction air is positioned in the same location. The E model cowl looks sleeker and cleaner without the chin of the C model, but neither win an award for good aerodynamics.

The E model cowling shares two things in common with the C model cowl--1) aerodynamically and 2) mechanically it is a poor design. Aerodynamic deficiencies are an oversized inlet area for cooling air to enter, too small exit areas underneath and behind the cowl flaps for this cooling air to exit, and a too flat frontal area. All this adds up to one thing-- drag. And lots of it. When the M20J (201) was developed in 1976, the first thing the engineers in Kerrville redesigned was this cowling configuration that had carried over the years. Rightfully so-- the cowling is the biggest single source of aerodynamic drag on early Mooneys. MAPA members call all the time wondering what the most effective speed mod is they can put on their pre-J model airplane. The answer is simple--install a 20l style cowling. They're expensive, but give the most speed increase for the money.

Mechanically, this cowling isn't any better. Did Mooney's engineers in the 60's ever hear of the term "preflight check of the engine compartment"? There are more sheet metal screws holding this cowling together than you can count. Just like all the other early Mooneys (and the new ones aren't much better), better come to the airport 30 minutes early if you plan to remove the cowling for a proper engine compartment preflight. Or come out the day before if you don't want to keep your passengers waiting in the cold, heat or rain while you struggle with removing and reinstalling 50 or 60 screws. This is one of the few areas where I envy our Bonanza and Arrow brothers--flipping a few latches they can see the entire engine and exhaust systems on their airplanes. We, on the other hand, are stuck with a major construction project just to get two side panels removed for a basic look at a portion of the engine. Bad engineering on Mooney's part.

One last word on this and I'll quit harping on it. As I said in the C model article in the August issue, we are seeing more and more in-flight mechanical failures inside the engine compartment that could have been caught with a proper preflight. But due to the difficulty in removing the panels of these cowlings, we aren't taking the time to remove all the sheet metal screws for a proper preflight of the engine compartment. But can anyone blame us?

Another area where the M2OE (as well as the M2OC) falls short is in the area of "ramp appeal". Just like its C model brother, the E model sits low to the ground and looks small compared to other single engine airplanes on the ramp. Passengers will notice this and start questioning you about the strength of this airplane you are about to take them flying in. To passengers, "big" and "strong" go together. You and I know this is hogwash-- there is no stronger airframe in the world than a Mooney. But try convincing your non-aviation passengers. It gets kind of old reassuring everyone that this "little" Mooney is just as strong as the Bonanza or Cessna 182 towering over it from the next tie down space. But this goes with the territory if you own and fly an early (or even a late model) Mooney.

Enough "ramp chat". Let's get inside, buckle in and look around. I discussed it at length in the August issue on the C model, but short-body Mooneys don't make good four-place airplanes. Once seated inside, you'll see why - there isn?t enough legroom in the back and not enough cubic feet in the cabin for four adults. Our beloved shortbody Mooneys are great two-place airplanes with lots of stretch out room for the people in the front and lots of space for baggage in the back. But bring along a third occupant and things deteriorate quickly. A third passenger can sit in the back for a while by sitting "sidesaddle" with his or her feet sideways in the space on the other side. That's really uncomfortable (ever try to ride a bicycle like this?). But as a four-place airplane? Forget it. You bought the wrong airplane if you need to carry four. Four work much better in an M2OF, G or J with their longer fuselages and 8 inches more legroom for the rear seat passengers. Luckily, our seat is the best in the house-- the left front. Let's settle in and look around. Positioning the seat far enough forward to reach the rudder pedals puts your eyes and face very close to the instrument panel. Not a problem, but if you need to wear reading glasses (and I do), you'll need them in the E model. The panel is less than an arm's length away.

Frankly, I get a little uncomfortable sitting this close to the panel. I think back to my flight test days watching FAA crash tests done in the late 70's showing what happens in a sudden impact to the front seat occupants wearing lap belts only. The dummies used in these tests simply pivoted around the lap belt and impacted the panel with their face and head. Even a relatively slow 30 knot impact resulted in serious head and facial "injuries" to the dummies. If you have a Mooney without shoulder harnesses, you owe it to yourself and your passengers to install a set in the front seats. That panel is right in front of you. It will hurt when your face hits it. Our test airplane had inertial reel shoulder harnesses retrofitted ($300 per seat from Lake Aero Styling 1-800-954-5619). They worked perfectly. I gladly buckled up and prepared to fly.

The left hand cowl flap on the M20E. The exit area is too small and the cowl flaps should have "side skirts" for more efficiency. Same for the right.

This is where I came across what I think is the most serious operational aggravation of the M2OE - starting that darn tightly cowled fuel injected Lycoming IO-360-AlA engine. I consider myself a pretty competent Mooney pilot (3000 hours in type, former engineering test pilot). But I have to tell you that this engine in this airplane humbled me. I could start it cold. But hot? What a disaster! I almost ground the starter into a pile of metal shavings trying to get it to fire when hot. The mechanics at Lone Star Aviation would just line up at the hangar door and laugh at my starting attempts. It was 90 degrees F on the ramp during these evaluation flights. Inside the cockpit, it felt more like 150 degrees as I cranked away without any response from the engine.
But to my rescue came David McGee from All American Aircraft. David has probably started more M2OE models than anyone else in the country. David gave me his procedures on how to start the engine in the M2OE-- hot or cold. They worked perfectly! I was so impressed with his procedures that I have made a separate article in this issue of the Log (see page 26) that detail his M20E starting procedures. I thought I knew it all-- I have started lots and lots of J models over the years. But this was different. I didn't have a clue. David saved my day. See his article in this issue on how he starts the M2OE. It could save you from being pretty embarrassed in front of your passengers and fellow pilots on the ramp as you crank away on the starter in your M2OE without any results whatsoever.

The starting difficulties I encountered with the M2OE verifies that all airplanes are full of compromises. The M2OC with its carbureted 0-360-AID is a delight to start hot or cold. A few pumps on the throttle and the engine fires right away. The problem with this engine is that it can make ice in the carburetor. Not good when flying lots of IFR. The choice of the fuel injected IO-360-AIA in the M2OE eliminates the carb ice issue, but adds the compromise of hot starts that have to be finessed like playing a piano. So you make your choice - M2OC (carburetor) or M20E (fuel injection). Learn how to handle the carburetor ice threat with an M2OC or how to hot start the M20E--the choice is yours.

The instrument panel in our test airplane from the pilot's perspective. The instruments in thse airplane were rearranged into a basic "T" configuration, making IFR much easier. Highly recommended.

Once started, the M20E immediately shows the advantage of fuel injection. The engine idles smoothly and evenly. With the carbureted C model, better be on the mixture control quickly after the start, leaning for smooth operation and to save the plugs from fouling. You should lean the engine in the E model as well for ground operations, but you won't find as dramatic an improvement in smoothness as in the C model. But do it anyway--with both airplanes you?ll save the plugs from fouling if you aggressively lean for ground operations.

Pre-takeoff check is just as routine as is the C model. Controls, Instruments, Gas, Attitude (trim). Runup. I again liked the mag and prop cycle cheek at 1700 RPM in the E model, same as the C model. The airplane is much quieter at this lower RPM value than the newer airplanes. Flaps can be lowered to the takeoff position if you desire, but I have to tell you that they really aren't needed for most takeoffs. If the field is short, by all means use flaps--they will slightly reduce your ground roll. But the F model has such strong takeoff performance that you'll find the flaps aren't really necessary for most takeoffs. Power in for takeoff and what I think is one of the biggest attributes of the E model becomes quickly apparent. The E model has the strongest takeoff performance of all Mooney airplanes--bar none. The combination of 200 horsepower, short fuselage and light weight make this the best of all Mooneys when it comes to runway acceleration, takeoff distance and distance to climb over a 50 foot obstacle. This airplane really gets with the program during takeoff. My takeoffs were made with only myself on board, full fuel, a ground temperature of 90 degrees F and a density altitude of 3000 feet. By the time the power was all the way in, the airplane was ready to fly. I estimate that the takeoff distances were around 800 feet or so. There is no other Mooney that can touch these takeoff distances. Even the new ones. Certainly, the new ones have much more horsepower, but they are also a lot heavier. If you fly often from short runways, the E model is the best of the best Mooneys for short field operations. Positive rate of climb established after takeoff and all the engine parameters in the green, it's time for a manual gear retraction. I'm feeling pretty confident--I'm beginning to like this manual gear. Unlatch the lever, slide down the handle. Swing the bar towards the floor - and I realize I have the portable OPS antenna wire hooked with the Johnson bar! So here I am, gear stuck halfway up, tower calling to switch to departure control, trying to maintain the proper pitch attitude for climb and the stupid GPS wire tangled all around the gear handle. Rule number one for a manual gear Mooney pilot--make sure the path the gear handle travels during retraction and extension is clear at all times. I feel pretty stupid, but I wonder how many manual gear Mooney pilots have the same problem.

With the gear finally retracted, it's out to the test area to take a look at climb performance just as we did for the M2OC in the August issue. Our flight tests on both airplanes were done in the heat and low altitude turbulence of south Texas--perfect for measuring some real world climb performance data. I was also pretty light in both airplanes--about 300 pounds under max allowable gross weight. Test conditions for the C and F models were almost identical, so we should have some excellent "apples to apples" comparisons between the two airplanes.

For our M20E test airplane, two continuous climbs were performed from 1500 feet to 10,000 feet. One was made at 100 MIAS and the other at 120 MIAS. The procedure used for the climbs to altitude were 1) full throttle, 2) 2700 RPM, 3) mixture leaned to 100 degrees rich of peak EGT and 4) cowl flaps full open. As we discussed in the M2OC article, this is the most efficient way to climb any normally aspirated Mooney to altitude. Forget reduced power climbs (the old "25 squared" myth). You're giving away everything (performance) for nothing. And if possible, try to climb at a constant airspeed somewhere above Vy. Climbing at Vy usually isn't necessary (unless there are obstacles or mountains in the way). A climb speed higher than Vy gets the airplane to altitude almost as quickly as climbing at Vy, increases over the nose visibility, keeps the engine cooler and results in more horizontal distance covered across the ground while in the climb. Climbing the M2OE at full powe, leaned to 100 degrees rich of peak EGT and faster than Vy is flying your E model the way it was engineered to fly.

Using the procedures listed above, here is how the data turned out for our two continuous climbs in the M2OE:

Continuous Climb Data 1964 M2OE N69661U
Full throttle, 2700 rpm, mixture leaned to 100
degrees rich of peak, cowl flaps full open, airspeed as noted, ram air off
Climb #1 Airspeed at Constant 100 MIAS
Elapsed
Time
Altitude MIAS MP RPM Oil
Temp (F)
CHT
(F)
OAT
(F)
Rate
of Climb
FPM
0:00 1500 100 28.1 2700 140 390 85 ---
1:00 2500 100 27.1 2700 145 395 84 1000
2:00 3340 100 26.1 2700 145 395 79 840
3:00 4100 100 25.2 2700 145 395 74 760
4:00 4950 100 24.7 2700 145 395 69 850
5:00 5700 100 23.9 2700 140 395 68 750
6:00 6450 100 23.2 2700 145 395 66 750
7:00 7210 100 22.7 2700 145 400 66 760
8:00 7800 100 22.0 2700 145 400 66 590
9:00 8440 100 21.5 2700 150 400 66 640
10:00 9080 100 21.1 2700 150 405 65 640
10:40 10000 100 20.2 2700 150 405 65 640
Climb #2 Airspeed at Constant 120 MIAS
Elapsed
Time
Altitude MIAS MP RPM Oil
Temp (F)
CHT
(F)
OAT
(F)
Rate
of Climb
FPM
0:00 1500 120 28 2700 150 330 86 --
1:00 2510 120 27 2700 150 360 86 1010
2:00 3380 120 26 2700 150 380 83 870
3:00 4250 120 25.1 2700 150 380 80 870
4:00 5130 120 24.2 2700 150 390 76 390
5:00 5900 120 23.8 2700 145 390 71 770
6:00 6510 120 23.1 2700 145 390 67 610
7:00 7200 120 22.5 2700 140 385 64 690
8:00 7830 120 22 2700 140 380 62 630
9:00 8300 120 21.6 2700 140 380 61 470
10:00 8800 120 21.2 2700 140 380 60 500
11:00 9370 120 20.8 2700 140 380 60 570
12:21 10000 120 20.1 2700 140 380 60 476
Just as expected, these numbers show an improvement in climb performance over the C model. The extra 20 horsepower were in conditions almost identical for both airplanes. Single pilot, full fuel, hot day (90F plus on the ground), 100 and 120 MIAS climb speeds, full throttle, 2700 RPM, leaned to 100 degrees rich of peak, cowl flaps open. Let's take a look at the bottom line comparison between our C and E model test airplanes:

CLIMB PERFORMANCE COMPARISONS M20E -vs- M20C
Model Climb Speed
MIAS
Avg Rate of Climb
to 10000'
Max
Oil Temp
Max
CHT
E 100 797 fpm 150 405
C 100 657 fpm 205 440
Advantage E Model + 140 fpm
E 120 688 150 390
C 120 571 205 430
Advantage E Model + 117 fpm

So the extra 20 horsepower of the E model buys 140 FPM at 100 MIAS and 117 FPM at 120 MIAS. Not bad. There are times when a 100+ FPM increase in rate of climb can come in real handy, such as during a high density altitude takeoff or trying to climb over steep terrain. If climb performance is important in your flying, the climb advantage goes to the E model.

You'll note I performed the climb tests in the E model with the ram air control off. The ram air system installed in the F, model consists of a cockpit control that activates a small door in the lower cowling that allows unfiltered induction air to enter the engine's induction system. By bypassing the air filter, the induction system is allowed to "breath easier". The result is a one-inch or so manifold pressure increase (about 10 horsepower) when operating with the ram air control on (door open).

I didn't use the system in the climb because I wanted to see how the E model compared configured exactly as the C model. The C model doesn't have a ram air control, so I didn't use it with the E model. If I had performed the climbs in the E model with the ram air on, I would have gotten about 15-20 FPM more rate of climb. So, if you desire to climb your E model with the ram air on, expect another 15-20 FPM rate of climb increase. Just remember you're using unfiltered induction air in the lower levels.

I would like to make a comment from a technical standpoint about the ram air system on the E model. Mooney's marketing department made a big deal about the ram air system back in the '60's--a "poor man's turbocharger" and all that stuff. Talked about how it was a stroke of design genius to offer this primary induction system bypass to give added engine power and better airplane performance when flying in clean air.

Bull. There is no way a properly designed primary induction air system should have a 1" hg manifold pressure drop across the filter. I think the ram air system on the E model was simply a bandaid for a poorly designed primary (filtered) system. If Mooney's powerplant engineers had designed the primary induction air system properly in the first place, they wouldn't have had to incorporate this "ram air" idea. It's bad engineering to require the pilot to open an induction air bypass to get the engine performance he deserves in the first place. And unfiltered air is not good for the engine.

A good primary induction air system shouldn't have a 1" hg manifold pressure drop across the filter. For example, the later J models had about a .25" hg drop. That's why the factory dropped the "ram air" system on that airplane in later years--it wasn't worth anything. So, shame on Mooney's powerplant engineers in the '60's for designing a primary (filtered) induction air system on the E model with a 1" hg manifold pressure drop and requiring pilots to select unfiltered air for proper engine performance. Bad engineering. Bad marketing.

Gotta love that wing! We go fast in Mooneys because of the excellent wing design. The E model is no exception. Just look at that smooth surface, even after 36 years. A tribute to Mooney's craftsmanship.

So, we've shown the E model has better climb performance than the C. That was expected. But how about level flight cruise performance? Does the extra 20 horsepower of the E model and the slightly more aerodynamic cowling give it greater cruise performance than the C? Let's take a look.

Our cruise performance flight testing on the E was done identically to the C. Same altitudes, power settings and weights. We chose to measure cruise performance on the E model flying the airplane at its most efficient cruise power setting and configuration. If you fly an E model, you will get the most cruise performance and good economy from your airplane where we tested--full throttle, 2500 RPM, leaned to 50 degrees rich of peak EGT and cowl flaps closed.

Just like the C, the induction and exhaust systems on the F are designed (tuned) to be most efficient with the throttle in the full open position and at 2500 RPM for continuous cruise. The mixture setting is your choice. You can choose either 1) 100 degrees rich of peak EGT for best power (good speeds, but watch that fuel flow), 2) 50 degrees rich of peak EGT (my recommendation as a perfect compromise between best power and best economy), 3) peak EGT (best economy, but expect a 4 or 5 knot speed loss), or 4) 50 degrees lean of peak EGT with a set of balanced fuel injectors from GAMI.

My recommendation is for 50 degrees rich of peak EGT for any normally aspirated Mooney. The engine runs cool and smooth, aircraft performance is excellent and the fuel flows are quite good. So try full throttle, 2500 RPM and 50 degrees rich of peak EGT with your F model. I think you'll like what you see.

Our speed runs were accomplished using the four direction GPS method of determining true airspeed. Fly N, S, E, W (headings, not tracks) stabilized on altitude and speed, note stabilized GPS groundspeed for each direction and average the four. That average is the aircraft's true airspeed for the power setting and configuration you are flying. Here are the numbers for the E model. Ram air position (I hate this thing!) is noted.

Level Flight Cruise Performance 1964 M20E N6966U, Full throttle, 2500 rpm, 50 degrees rich of peak, cowl flaps closed.
Altitude
OAT
F
MP RAM
AIR
RPM Direction IAS
KTS/MP
GPS GROUNDSPEED
KTS
10000 64 20.1 off 2500 W 128/148 156
10000 64 20.1 off 2500 S 129/149 132
10000 64 20.1 off 2500 N 128/148 157
10000 64 20.1 off 2500 E 128/148 137
Average GS/TAS 145.5 kts.
7000 65 22.7 off 2500 E 140/162 141
7000 65 23.8 on 2500 E 144/166 144
7000 65 22.7 off 2500 S 140/162 136
7000 65 23.8 on 2500 S 143/165 140
7000 65 22.7 off 2500 W 139/160 160
7000 65 23.8 on 2500 W 143/165 165
7000 65 22.7 off 2500 N 140/162 161
7000 65 23.8 on 2500 N 144/166 166
Average GS/TAS (ram air off) 149.5 kts
Average GS/TAS (ram air on) 153.75 kts
4500 76 24.7 off 2500 W 144/166 152
4500 76 26.0 on 2500 W 146/168 153
4500 76 24.7 off 2500 S 143/164 138
4500 76 26.0 on 2500 S 144/166 140
4500 76 24.7 off 2500 E 143/164 149
4500 76 26.0 on 2500 E 146/168 151
4500 76 24.7 off 2500 N 143/164 158
4500 76 26.0 on 2500 N 144/166 162
Average GS/TAS (ram air off) 149.25 kts
Average GS/TAS (ram air on) 151.5 kts

As you can see, our test airplane, N6966U, exhibited excellent cruise numbers. Compared to the 200 horsepower, retractable gear competition in the pre-owned market, the E model is simply the fastest. A Cardinal RG can barely manage 140 KTAS on a good day. A 200 hp Arrow is a 135-140 KTAS airplane. A Beech Sierra is a pitiful 125-130 KTAS machine. Want to go fast? Buy an E model.

I didn't get any ram air on data at 10,000 feet because I forgot to activate the door. But as you can see from the 7000' and 4500' data, ram air on adds about 1" hg manifold pressure and 2.5 to 4 KTAS, depending on altitude. Just make sure to turn it off before you descend (I forgot) and don't use it when flying in visible moisture or, heaven forbid, in a sandstorm.

It's interesting to compare the speeds we found with our E model test airplane and the C model flown for the August issue. Here is how the two airplanes compared flying at exactly the same weights, power settings and altitudes:

Comparative Cruise Speeds M20E and M20C
Level flight, full throttle, 2500 RPM, 50 degrees rich of peak EGT, cowl flaps closed
Model Altitude Ram Air GPS Derived Cruise Speed, KTAS
E 10000 off 145.5
C 10000 --- 139.0
Advantage E model +6.5 KTAS ram air off
E 7000 on 158.75
E 7000 off 149.50
C 7000 --- 143.50
Advantage E model +10.25 KTAS ram air on
+6.0 KTAS ram air off
E 4500 on 151.50
E 4500 off 149.25
C 4500 --- 146.75
Advantage E model +4.75 KTAS ram air on
+2.50 KTAS ram air off

So, we have proven that the E model has about a 130 FPM advantage in climb over the C model and is faster anywhere from 2.5 KTAS (ram air off down low) to 10.25 KTAS (ram air on up high) faster. Those 20 extra horsepower and slightly cleaner nose cowl do make a difference. And so does that ram air system, although I still don't like it.

But I must pause here to discuss an issue with the pre-'69 C and E models concerning airspeed--specifically airspeed limitations. The early '64 E model I flew has a top of the green arc airspeed of 150 MPH IAS, just like the '66 C model I flew for August. This limitation did improve in the later years--both airplanes increased their top of the green arcs to 175 MPH IAS for the 1969 model year. But for those of us who fly pre '69 C and E models, be prepared to spend a lot of time in the yellow arc in level cruise and certainly in descent. My gosh, about the only time you're not flying in the yellow are in a pre '69 C or E model is during climb! There are no other general aviation airplanes I know of that spend so much time with indicated airspeeds in the yellow arc.

Say what you will, but this is not a good feeling. Descending through turbulence in an early C or E model 20 or 30 MPH into the yellow arc is not comforting. First of all, with its relatively light wing loading compared to the later, heavier Mooneys, the E model is just getting clobbered by the rough air. You better have a strong spine if you fly an early E model, because high speed descents in much air will be hammering you around pretty good. This really isn't a structural consideration---we all know how tough the Mooney's airframe design is. The wings aren't about to fall off or anything. It's just a question of ride quality and passenger comfort. At speeds well into the yellow arc, every little bump in the air is magnified into a major airframe displacement. It's pretty uncomfortable.

Another negative to mention on the E model we flew for this report are the poor handling qualities in roll, but this complaint is for airplanes built prior to 1965 only. Specifically, pre'65 Mooneys all had ailerons that were "curved" on the bottom surface. These curved ailerons resulted in very high roll forces. The test pilot term for this is "high breakout forces". Roll rates with these curved ailerons are good---once the ailerons are displaced, the airplane rolls crisply and quickly. However, the forces required on the control wheel to get these roll rates are extremely high. When I made my first turn out of the traffic pattern in 66U, I thought 1) the PC was on, or 2) the autopilot was engaged, or 3) something was jammed in the aileron control system--these aileron forces were really high! But everything was okay. It's just the design - the curved ailerons on the pre '65 models require Popeye forearms. And the higher the speed, the higher the aileron forces. At 170 MPH IAS, these ailerons feel like they are cast in concrete.

This view clearly shows the curved aileron on our '64E Model test airplane on the left. Compare it to the straight-bottomed aileron shown on the right on a '66 C Model. Expect high roll forces with the curved ailerons.

The good news is that the later model ailerons can be retrofitted to the pre'65 model Mooneys. They are expensive ($800 from the salvage yard, $1500 from Mooney) but they make a dramatic improvement in reducing roll forces. Incidently, this aileron change is required if retrofitting a PC system or an autopilot to a pre'65 model Mooney.

At the lower end of the speed envelope, handling qualities are much better. Stall characteristics in the M2OE we flew for this report were identical to the C model we flew earlier - excellent. Stalls in early Mooneys are a non-event. There is no tendeney to drop a wing and a simple relaxation of the back pressure gets the airplane flying again quickly. I found the indicated stall speeds to be 67 MPH IAS clean and 61 MPH IAS in the landing configuration (gear down, full flaps) in 66U at the weight we were flying, almost identical to the C model flown earlier.

Using the rule of setting threshold approach speeds at 1.2 times the stall speed for the configuration being flown. I made several landings in the E model using 73 MIAS "over the fence" flaps full down and 80 MIAS with the flaps up. These speeds worked perfectly -- just the right amount of energy and airspeed for a nice flare and landing. And the landing distances are short when using these threshold speeds---weIl under 1000 feet.

If there is one area where we Mooney pilots mess up the most, it's approaching too fast. I'm hearing speeds of 100-120 MIAS over the fence. These numbers are way, way too high. At least, you'll burn up the brakes using these kinds of threshold speeds. At worst, you might need more runway to stop than is available. We hear of a Mooney landing overshoot and an excursion into the weeds once a week here at MAPA headquarters. That's a shame, because crossing the threshold at the proper speed would eliminate this. Try using 75-80 MIAS as a target threshold speed on your next landing or two in your B, C, E, F, G or J model. You'll like what you see and feel.

Yep, it's a Mooney! Note the "short rudder" with the fixed tailcone. Indicative of a pre'68 C or E.

So, that's our look at the M20E, plusses and minuses considered. It's a wonderful two-place airplane, a barely acceptable three-place airplane for an hour or so and an impossible four-place airplane. In the front, you sit close to the panel and should consider retrofitting shoulder harnesses in the front seats a must for you and your passenger's safety. Expect limited panel space and a hodgepodge instrument layout in pre'ó9 models. Pre'65 models have very high aileron forces and the manual gear is either loved or hated, depending on whom you talk to. The fuel-injected engine in the M20E eliminates the worry of carburetor ice but adds the aggravation of hot starts. And like the C model, proper engine preflights are impossible without taking 30 minutes to remove and replace lots of sheet metal screws.

But oh my, that performance! We proved an E model is, for all practical purposes, a 150 KTAS airplane. This blows away all the other 200 horsepower competition. Fuel burn for these types of speeds should he right at 10.5 gallons per hour. With 52 galIons of fuel, this makes the E model a good "just under four hour" airplane with adequate VFR reserves. The E model is capable of cruise climing direct to 10,000 feet on a hot day in 12 minutes or so. Compared to the C model, buying an E will add 120 FPM or so to your climb capability and at least 5-7 KTAS to your cruise speeds (maybe even 10 KTAS, depending on altitude).

What's the current market demand for E models? High. And getting higher. We see most good, clean E models with decent avionics going in the range of $55,000 - $65,000. Hard to believe, isn't it? Pre-J model Mooneys are all appreciating like crazy. Our 64 E model test airplane. N6966U, is a classic example. Great airframe, newly overhauled engine, new paint, extensive airframe refurbishment, fair interior, fair avionics. The airplane sold for $59,000. Wow!

Early Mooneys have pretty good visibility. The two-piece windshield (left) gives acceptable visibility over the nose in level cruise flight (center). The side windows (right) are cut pretty high into the cabin, giving decent visibility to the sides. But you can't see out like in a Cessna or a Beech.

But speed and economy sells. Always has and always will. As fuel prices escalate (now approaching $3.00 a gallon in some places), so will the value of our Mooneys. Nothing delivers like a Mooney in these two critical areas. However, Mooneys aren't perfect. They're full of compromises. I've tried to point then out in these series of articles. But I have to tell you, they're compromises we're all willing to make. I like the speed and I feel safe when flying a Mooney. I don't get this same feeling in any other airplane. I'm sure you feel the same way. And in the end, does anything else really matter?

If you're deciding between an E and a C model Mooney, the extra 20 hp does make a difference. The airplane just feels stronger in climb and cruise and the match of the 200 hp engine to the short body Mooney airframe seems perfect. The fuel injected engine does add level of safety to IFR operations. Carburetor ice is a problem with the M20C. This is something you don't have to deal with in the E model.

So is the extra $10,000 or so worth it to buy an E model over a C model? The answer comes after you analyze the type of flying you plan to do.. Lots of IFR. serious cross-country transportation or high density altitude takeoffs? By all means buy an E model. If your IFR operations are limited, your normal trips are under 500 nautical miles. and most of your flying is east of the Rockies, the C model will do just fine.

Personally, I would spend the extra money for the E model. I would add a speed mod to the cowling and rearrange the instrument panel into the hasic "T" configuration. I fly lots of IFR and I can't stand the aerodynamics of the pre-J model cowlings. But that's my choice. Quite frankly, you can't go wrong with either airplane. After all, they're both Mooneys.