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C 172 Techniques
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C-172 Information; ... C-172 Model (Re-engined model N); ...1955 to 1986 C-172 Differences; ...Lycoming; ...Takeoff/Landing Comparison; ...C-172 Differences and Checkout; ...Damaging Aircraft; …Exercise in C-172; ...C-172 Procedures; and LandingsPrecision Approach Speed No Flaps; …Level Cruise; …Climb at 90 Knots; …Level Approach Speed at 90 Knots; ...Level Approach Speed at 90 Knots #2; ...Approach Descent Speed at 90 Knots; ...Slips with Flaps; ...Landing Problem; …Second Opinion; …Fuel Problems of Cessnas; … C-172R Data Sheet; ...A Better Way to Move a Cessna; ...Cessna vs Piper ...Aircraft Proficiency Checkout; ...Unorthodox Short Field Landing; ...Crash Landing Problem; ...Modified C-172s; ...1963 C-172 Suggestions; ...

C-172 Information
This TCDS covers all 172s. For models 172 through early 172Ms the Vfe limitation is 87 knots. From later 172Ms through the 172R the Vfe limitation is 85 knots. This is the highest speed, in general, that the pilot should extend *full* flaps. The Cessna 172 Type Certificate Data Sheet (3A12) is located at

C-172 FAA Type Certificate Data
In the case of the 172 SP, the W&B limitations are contained in FAA Type Certificate Data Sheet (TCDS) 3A12 (which covers all 172s) Note 1 which states: XII - Model 172S, Skyhawk SP, 4 PCLM (Normal Category), 2 PCLM (Utility Category), Approved May 1, 1998

C.G. Range Normal Category
(1) Aft Limits 47.3 inches aft of datum at 2,550 pounds or less.
(2) Forward Limits Linear variation from 41.0 inches aft of datum at 2,550 pounds to 35.0 inches aft of datum at 1,950 pounds; 35.0 inches aft of datum at 1,950 pounds or less.

Utility Category
(1) Aft Limits 40.5 inches aft of datum at 2,200 pounds or less.
(2) Forward Limits Linear variation from 37.5 inches aft of datum at 2,200 pounds to 35.0 inches aft of datum at 1,950 pounds; 35.0 inches aft of datum at 1,950 pounds or less.

The key to the 400-pound limitation you see on your chart is derived from the shifting datum line at the variable weights. The manufacturer determined that there should (actually must) be a 400-pound limitation for the two front seats in order to meet the structural limitations contained in the regulations.
Rick Cremer

C-172 has best G.A. fatal accident record at .56 per 100,000 flight hours. This figures out to one accident for every 18,000 hours of C-172 flight. Using the figure that the average serious injury/fatal accident occurs in only one of every six accidents, we find that an injury accident will occur 110, 000 hours of flight time. I want to fly long enough to have an injury accident.

Not long ago I saw four people get into the C-172. I questioned the pilot regarding weight and he said that he was in limits. When the heavyweight of the group got into the back seat, I again approached the pilot and suggested that balance might be a problem. What can be done? First, I don't believe anyone deliberately, and knowingly damages an aircraft or exposes passengers to danger. A pilot may have erroneous perceptions as to what makes a good landing. Maybe, there is a problem with knowing aircraft attitudes. Is establishing a stabilized approach at a constant airspeed the problem? Very possibly, it is caused by a situation beyond the pilot's experience. Instructional flying is five times safer than other G.A. flying. Since so much instruction is done in the C-172 it is logical to expect that the C-172 has an excellent safety record when compared to complex-high-performance aircraft.

A single pilot in a C-172 with his seat well forward; the C-172 with a a full radio stack; and The aircraft is within C.G. limits presents a potential flying control problem. A final approach at 60 knots will give the elevators enough authority to round out. As the aircraft decelerates below 60 knots the elevator loses authority and may well be unable to raise the nose, even if full back and up. This is especially true if the power has been taken off.

Under these conditions, what should the pilot do? If you can't arrange to get one passenger in the back seat, you should plan to leave at least 1200 rpm. The power will help hold the nose up and give the elevator the authority required for a full stall landing. Very careful energy management will be required to avoid a balloon. It can be done to a full stall landing every time. You will not be able to see the runway. The nose wheel will remain well clear of the ground. Power can be applied for the takeoff and the flaps removed without the nose wheel ever touching the ground. Alternatively, the power can be taken off as the nose wheel touches.

Aircraft damage due to landings is mostly accumulative. Occasionally damage happens all at once but usually it is accumulative. The gearbox can take thousands of average landings without any damage. The spring gear can take a heck of a beating. The severe damage to Cessnas is to the gearbox underneath the seats. One falling out of the sky from 20' can break the box. Repair or replacement of a C-172 gearbox can cost $9,000. The nose gear is attached to the firewall. A very hard landing on the nose wheel can damage the firewall.

Flying an aircraft with a bent firewall is enough to trigger an FAA investigation. Try to inspect the firewall of a C-172 or C-182 without removing the cowling. Is the nose wheel fork bent? Inadequate preflight the FAA calls it. It took me 14 months to shake them loose.

The C-172 generic landing uses 70 knots for downwind and final adding two ten-degree notches of flaps while taking off two full turns of trim. On final you put in full flaps and no trim change. You are on a stabilized approach hands-off at 60 knots. For the go-around, on bringing up the flaps you will be trimmed for a 75-knot climb. The hard part of flying the C-172 is leveling off. The old joke about how long it take a student to level off a C-172 is answered with, "Thirty-five hours". It will take about one and one-third turns of trim and a close eye on the altitude while the plane accelerates. The trick is to reduce to 2450 as soon as you reach 100 knots. Otherwise, you will be jockeying airspeed and trim for quite a while. The cause of this problem is that the C-172 has less power for its weight than the C-150. The time to accelerate to 100 knots seems to take forever. Initially you will be holding backpressure and then forward pressure on the yoke while the airspeed gets sorted out. Due to deceleration the C-172 power should only be reduced to 1700. At approach speed the power will have dropped to 1500 rpm

C-172 Model M (Re-engined to model N)
The change of 1407U to a C-172N by the addition of the 160 H.P. engine will increase the fuel consumption rate to around 8+ gph. I would suggest each pilot run some fuel consumption tests to compute figures for their mode of operation. To do otherwise is unsafe.

Note: Use of a C-172 information manual other than for a C-172N will give erroneous information.

Power: New engine 1995 is 160 h.p. and has higher fuel consumption than previous 150 h.p. Fly conservative until consumption is known. Speed: Do not use manual figures. For cross-country the use of 105K will work about right.

C-172 Information 1407U C-172 Model N. The new engine makes it Model N since the flap deflection has been limited to 30 degrees.

Speed: Do not use manual figures for cross-country. The use of 105 kph will work about right. This may change with new 160 hp engine but not by much. Power mostly affects rate of climb. Cruise: Recommended lean mixture with fuel allowance for engine start, taxi, takeoff, climb and 45 minutes reserve at 45% power. 75% power at 8000' Range 450 nm no reserve. Cessna has a bulletin on the C-152 that indicates full rich operations will decrease range by over an hour and increase fuel consumption by 40%. Similar figures would probably apply to the C-172.

C-172M 1975-6
hp - 150
Gross - 2300
Empty - 1335
Useful - 965
Cruise - 122kts
Climb - 643
New - 27,600
Current 41,500
Value retention 141%

Time 3.9 (Recommend 3 hours maximum)
Sea Level rate of climb 770 fpm
Service Ceiling 14,200
Takeoff Performance
Ground roll 865'
Over 50' obstacle 1440
Landing Performance
Ground roll 520'
Over 50' obstacle 250
CAS Stall Speed
Clean power off 50 kts
Dirty power off 44 kts

Empty weight and useful load.......consult weight and balance papers
C-172 is vulnerable to dangerous weight and balance conditions.
Gross to/landing weight 2300 lb.
Baggage allowance 120 lb.
Wing Loading 14.4
Fuel Capacity 42 gallons
Useable 39 gallons
Fuel consumption...................160 h.p. engine in 1995 changes figures
Engine- Lycoming 160 hp. (14.4 lb. per hp)
At 2500 rpm at 2000' 76% power and leaned uses 8.5 gph.
At 2400 rpm at 8000' 60% power 6.7 gph

The N has 160 hp and 30 degrees of flaps. These make it possible to increase the useful and gross because of the go-around requirements. Slips with flaps are either prohibited or not recommended in the POHs. The slip problem arises from the possibility of extended flaps under certain conditions such as in slips or wind shear blocking or interfering with the airflow over the horizontal tail surfaces. I have had such an occurrence in a C-150. The tail surfaces stall and the nose pitches straight down before the stall warner has a chance to yelp. Cessna merely admits that there may be control oscillations.

1955 to 1986 C-172 Differences
36,000 C-172s have been manufactured since the first one in June of 1955. The C-172 has the best safety record of aircraft in its class. The 1956 model had a 145 hp Continental. The 1960 model had a swept tail. In 1963 a rear window appeared as well as single piece windshield and longer elevator. The 1956 to 60 C-172 had a low panel that allowed the pilot to 'look down' over the 145 H.P. engine. Over 30,000 C-172s have been built in 43 years. 1960-63 enter the swept tail and no-window fuselage. Enter the window in the back and then we have a series of changes in engine, landing gear, and cockpit but essential things remained the same. The 1964 model had electric flaps instead of the Johnson Bar. 1968 models switched to Lycoming 150 hp engines. In 1971 the spring steel gear was changed to tubular. In 1972 the dorsal fin was extended to correct pitch problems during slips. 1973 changed the wing leading edge to a droop as well as a shorter propeller. An engine change in 1972 was a disaster due to inadequate lubrication. 1978 saw the 24-volt electrical system and better seats. 1981 gave a 160-hp engine and gross weight of 2400lbs but reduced flap travel of 30 degrees. 1986 changed the angle of the horizontal stabilizer to improve pitch authority. Popular modifications include such things as 180 hp engines and possibly constant speed props. Sound reduction through use of thicker windshield, long range tanks and electronic upgrades are common.

The large slotted flaps in older Cessnas can a nose down pitch in forward slips. A cautionary warning is in many POHs indicating that slips should be avoided when using maximum flaps. The pitching motion is the result of the difference between a strong wing downwash over the tail in straight flight to a reduced downwash influenced by a raised aileron in slipping flight. This effect is elusive hard to duplicate, I have experienced it only once in over 9000 hours. This restriction does not apply to the wing-low drift correction used in crosswind landings.

When the larger dorsal fin was adopted in the 1972 C-172L, this sideslip pitch event was eliminated. In the higher-powered C-172s the placard was applicable to a mild pitch from flap outboard-end vortex hitting on the horizontal tail at some combinations of side-slip angle, power and airspeed."

Over sixteen C-172s are involved in accidents every month. One accident every two days. This gives a rate per 100,000 flight hours of 1.46. Prior to 1977 the C-172 engine failure rate was one per every 5.6 million hours of operation. Only one in six of these accidents result in personal injury. Night accidents in C-172 occur at nearly a 20% higher rate than day accidents.

85% of all C-172 accidents are due to pilot error. This is more than accidents in other types. The aircraft has been deemed responsible in 7% of the accidents. The percentage of C-172 accidents is highest when the pilot involved has between 100 and 200 hours of flight time. 50% of the accidents occurred when the pilot had less than 50 hours in the C-172 type aircraft. A high percentage of C-172 accidents have been attributed to inadequate checkouts.

C-172s have twice as many hard landings as a PA-28 (Cherokee) per aircraft. The C-172 is four times as likely to have a wind related accident. It has twice as many go-around accidents. NRI Flying Club has spent no less than $4,500.00 in the last two years on just nose-strut repair and nose gear rebuilding of O7U. This is certainly indicative of a problem in piloting, checkouts, and instruction. Making flat landings or nose wheel first are the problem.

The C-172 has half as many fuel exhaustion accidents as like powered low-wing aircraft. Crosswind takeoff and landing accidents were relatively frequent and attributable to inadequate checkouts. The second major area of accident was the go-around, which has been partially corrected by Cessna by reducing flap extension to only 30 degrees on later models. Serious C-172 accidents were generally related to controlled flight into terrain or obstructions. (Low level flight) To fly the C-172 you must practice landing in different flap configurations and power settings. You must know how to hold the control for taxiing. The C-172 go-around requires anticipation and attention to the procedures for flap removal. It takes practice of the right kind to bring an improvement and a change in our maintenance costs. Years ago the Club lost a C-172 because the pilot attempted to make a go-around without removing at least partial flaps.

Airworthiness Directives are less common to the C-172 than other aircraft. Check the security of the aileron counterbalance weights, seat tracks for locking, flaps for smoothness of jack screw, and the panel lighting rheostat and you have the ADs pretty well covered.

First decide that aircraft is idling correctly
1. Operate engine for 1- minute at 1200 rpm. This might be done taxiing but it is relatively hard on the brakes.
2. Increase to 1800 for 20-seconds
3. Reduce to 1200 rpm and kill with mixture.

Takeoff/Landing Comparison
C-150 Take Off 735' /50' 1385 Landing Distance 445 /50' 1075

C-172 Take Off 945 /50' 1685 Landing Distance 550 /50' 1295
--C-172 Use 10 degrees for soft field or short roll but not for obstacle clearance.

C-182 Take Off 795 /50' 1625 Landing Distance 545 /50' 1285

An airplane should not be expected to get out of a space where it has landed.

C-172 Differences and Checkout
Be careful loading a C-172. A C-172 has four seats but is really a three passenger aircraft. Avoid putting weight in the back. C.G. is critical. What you can carry and where you can carry it will depend on the individual situation. Fuel consumption can cause a shift in the C. G. range. Useful load varies because of installed equipment that is included in the empty weight. Fuel consumption will vary with the loading. A heavy C-172 will require fuel after less than three hours of flight. Don't believe the manual on range, speed, capacity, or fuel consumption.

The time of year (temperature) has a significant effect on C-172 performance. Aircraft performance early in the morning or in the winter will decrease at warmer temperatures. What the C-172 was able to do in the winter, it will not be able to do in the summer. Warm air does not have the same ground effect as cool air. The C-172 is NOT a good high altitude or density altitude aircraft. C-172 performance requires careful planning, loading, cruise, and flight procedures.

Some of the performance for the C-172 at gross is poorer than that of the Cessna two-seaters. The C-172 takes longer to accelerate to its cruise of 100+ Kts than a C-150 does to its cruise of 85 Kts. Your first takeoff in a C-172 will surprise you as it departs for the left side of the runway when power is applied. You must anticipate this P-factor and torque with right rudder. Controls are heavier and response slower than trainers. Correct trim use becomes important. Failure to anticipate trim settings is a typical pilot problem.

Trim adjustments must be made during the descent and fine adjustments made when level. If the climb and level off is done at assigned altitude, then the plane must be deliberately over trimmed to require backpressure to hold the altitude. The altitude must be held for up to three minutes at higher density altitudes before any power reduction. This allows the plane to accelerate rather than climb.

The most important adjustment between flying the C-150 and the C-172 is in performing the transition from climb to level cruise. For the next several minutes the airplane will proceed to both accelerate and climb. The 'new to type' pilot will be several hundred feet high and have to go through the leveling process all over again. Because of its power to weight ratio and drag, the C-172 takes a while to accelerate from climb to cruise speed.

The pilot must be prepared to anticipate the amount of trim setting and yoke pressures required to maintain altitude for the time it takes the C-172 to accelerate to 100 kts. At 100+ knots the power should be reduced to 2450 rpm and trim adjusted. Even slight changes in altitude or power during this transition can make the transition to level flight take much longer. If the climb and level off is to be done at an assigned altitude, then the plane must be deliberately over-trimmed to require backpressure to hold the altitude during acceleration.

The most common fault in leveling off is to trim for level flight immediately and then proceeding to other activities. For the next several minutes the airplane will proceed to both accelerate and climb. The 'new to type pilot' will be several hundred feet high and have to go through the leveling process all over again. One solution for this is to climb 1 to 2 hundred feet higher than the desired altitude and then dive and accelerate to the assigned altitude. (Not an IFR procedure) Trim adjustments must be made during the descent and fine adjustments made when level.

The C-172 can be flown just like a C-150, however, to do so is both uneconomical and a sign of incompetence. In several very important particulars the C-172 should be flown differently than the C-150. While the C-172 may have more horsepower than the C-150, it actually has less power per pound. The C-150 can be made to climb at gross with full flaps. The C-172 has difficulty just to maintain altitude. Any go-around with a C-172 must include removing the drag due to flaps. Because of its power to weight ratio, the C-172 takes a while to accelerate in any situation. The new 160 h.p. engine will help but only marginally. Additional power benefits climb more than any other performance factor.

The C-172 has a much higher and deeper instrument panel, which may require shorter pilots consider putting their flight materials into a pillow type carrying case. When level, the C-172 seems to have a slightly nose down attitude somewhat different than that of a C-150. In level flight the nose is low enough to be easily seen over. The C-172 nose position is one of the transitions you need to get used to. The C-172 now has a four position fuel selector. An imbalance in fuel use can be corrected only by going to the fullest tank for a period of time. Don't try to put the selector part way or your engine will stop. Older C-172s require single tank operation above 5000'.

If the trainee has been taught to slow the C-150 on airport arrival prior to the numbers, this rather uneconomical technique will carry over to the C-172. The fact is that the extra speed of the C-172 on downwind will give the correct pattern size and spacing if properly used. For instance, to obtain 1500 RPM in the C-172 the throttle setting should initially be reduced only to 1700 RPM. As the aircraft decelerates at the pattern altitude, the RPM will fall to 1500 RPM. The entire transition process becomes very easy if the constants of trim, power setting, airspeed, are carried from the C-150 to the C-172. The pattern speeds of the C-172 may be different from downwind, and, base. These speeds while different are constant. Slow to 80 knots after the numbers, 70 knots on base and 60 knots for final. Other speed sequences will work just as well.

The older C-172, like the C-150, has a built in engineering relationship between power setting, flap application, and trim. Knowledge of these factors allow a pilot to 'know' what power, flap and trim settings will give the 'hands-off' performance desired. The C-172 requires full movement of the trim for no flap slow flight and only 17/1800 RPM. Abeam the numbers, three down trims and power to 1700 from cruise will give 70 kts and 1500 RPM at the key position just before base. A one for one with 10 degrees of flaps and trim will maintain 70 kts until turning final. On final full flaps will not require any additional trim and the approach speed will fall to 60 kts. After landing and flaps up, the aircraft is properly trimmed for climb. (Likewise, the C-152)

The flap and no-flap pattern and approach speeds of a C-172 can be the same. The use of flaps improves the aiming descent angle on final and can reduce the ground impact speed. Proper flare in a C-172 greatly reduces structural loads and touchdown speed. You must work to get a full-stall minimum speed touchdown in the C-172. The C-172 tends to lose elevator power in flare and will be unable to raise the nose unless the elevator effectiveness is augmented by prop-wash. Try landing with 1200 rpm and see the difference attained in nose attitude. The landings are even easier with less than 40-degrees of flap.

The landing configuration with flaps means that the runway will not be in view for a proper (full stall) landing. The C-172 nose position is one of the transitions you need to get used to both for level and landing. Good landings of the C-172 with the nose wheel off the ground require precise use of yoke, flaps, and power. To fly the C-172 you must practice landing in different flap configurations and power settings. You must know how to hold the control for taxiing. The C-172 go-around requires anticipation and attention to the procedures for flap removal. Evidence based on NRI maintenance would indicate an on-going problem.

One of the more difficult aspects of making the transition to a C-172 is directly related to its power to weight ratio. The C-172 takes longer to achieve cruise speed when leveled off than do most other aircraft. The traditional saying is, "How long does it take a student to level off a C-172?" (Answer below)

I have found it desirable to initiate the instruction from established cruise airspeed with power at 2450 rpm. Note the airspeed indicated at cruise. Have the student index (memorize) the amount of trim change required to establish a hands-off climb at 75 knots at full power. With this information a student can learn to level off a C-172 quite quickly as well as initiate a stabilized climb.

I have found many students who come to me with prior instruction tend to level off with an initial reduction to cruise power. WRONG! This means that a C-172 must accelerate to cruise speed using cruise power. It will take several minutes and a constant adjustment of the trim. Typical result is for the aircraft winding up 200' high and still out of trim. Students using this method will take 35 hours to learn to level off.

The most efficient way to level off a C-172 is to leave climb power full on during the initial leveling off. Use the yoke to lower the nose and forward pressure to hold heading and altitude. Roll the trim wheel up one full turn and perhaps a half more. Continue holding the heading and altitude while the aircraft accelerates to cruise speed. Use sound as an indicator as to when you should take a look away from the horizon and to the airspeed indicator. At cruise speed reduce power to 2450.

Exceeding cruise speed or being below cruise speed before reducing the power means that your trim setting as indexed will be wrong. This means you must hold heading and altitude with yoke pressure until the aircraft acquires its natural cruise speed. This problem is easily avoided by reducing the power at the proper time. One way to check the level cruise attitude and trim is just to place both hands on the cowling pad and note that the nose begins to drop. Put your hands over your head and the nose rises. Normal hand position gives level flight.

The more accurately you determine normal cruise speed and the index of trim difference between climb and level the faster you can level off. For those who are working on their IFR rating you might work on additional trim/power indexes as required for 90 knot climbs, level, and descents. Learn the sounds of your aircraft just as you know the sounds of your automobile. With a safety pilot practice making the throttle and trim changes with your eyes can be done and makes it so that flying the airplane is not a part of the IFR problem.

For a given configuration (Weight, flaps, gear, etc.) Pitch + Power = Performance. Otherwise, if you pitch to Vy attitude, add full power on your Skyhawk you expect to get about 75kts airspeed and 700 fpm climb (Performance). (Standard conditions +10-20 degrees.)

Useful information to know would be the pitch attitude and power setting (RPM) to use to maintain altitude, descend at 500 fpm and climb at 500 fpm while holding 75 kts airspeed. Do the same for 65 and 85 kts. For highest speed flying go to 7500 feet with 2700 rpm and leaned. For fuel efficiency use 2500 rpm for a 10% fuel saving.

If you can fly the same aircraft most of the time you can develop a sense, which will help you immensely. Set any configuration you want, and listen to the sounds. By changing the configuration you can get an ear for the next set of specific sounds. You can literally learn to tune your aircraft by ear. You can find a functional relationship between RPM and air speed in a specific configuration.

Damaging Aircraft
Aircraft damage due to landings is mostly accumulative. Occasionally it happens all at once but usually it is accumulative. The gearbox can take thousands of average landings without any damage. The spring gear can take a heck of a beating. The severe damage to Cessnas is to the gear box underneath the seats. One falling out of the sky from 20' can break the box. Repair or replacement of a C-172 gear box can cost $9,000. The nose gear is attached to the firewall. A very hard landing on the nose wheel can damage the firewall. Flying an aircraft with a bent firewall is enough to trigger an FAA investigation. Try to inspect the firewall of a C-172 or C-182 without removing the cowling. Is the nose wheel fork bent? Inadequate preflight the FAA calls it. It took me 14 months to shake them loose.

The accumulative damage mostly occurs to the nose gear. The oleo strut can survive forever if the landings are on the main gear. When the nose wheel becomes a part of the initial landing contact it becomes life limited. Every compression of the strut loses some air and perhaps oil. If the strut is not cleaned prior to every flight the accumulated oil and dirt act like sandpaper on the 'O' ring. After a number of nose wheel compression cycles the strut will become flat and knock against the wheel even when taxiing. Every subsequent landing causes the shock of the nose wheel landing to be transmitted into the firewall and the engine mounting. Now, the damage is not just to the gear but in the engine and the aircraft airframe. I recently (February '94)saw someone taking the NRI 172 and make somewhere between 4 and 6 touch-and-go's. Every one of the 'landings' was flat. Not once was the nose wheel held off the runway for even a moment.

Not long before that I saw four people get into the C-172. I questioned the pilot regarding weight and he said that he was in limits. When the heavy-weight of the group got into the back seat, I again approached the pilot and suggested that balance might be a problem. Is there a problem or is Gene Whitt making one? Saw the same thing in Hayward yesterday 11-14-98.

What can be done? First, I don't believe anyone deliberately, and knowingly damages an aircraft or exposes passengers to danger. A pilot may have erroneous perceptions as to what makes a good landing. Maybe, there is a problem with knowing aircraft attitudes. Is establishing a stabilized approach at a constant airspeed the problem? Very possibly, it is caused by a situation beyond the pilot's experience. Consider.

A single pilot in a C-172 with his seat well forward. The C-172 has a full radio stack. The aircraft is within C.G. limits. A final approach at 60 knots will give the elevators enough authority to round out. As the aircraft decelerates below 60 knots the elevator loses authority and may well be unable to raise the nose even if full back and up. This is especially true if the power has been taken off.

Under these conditions, what should the pilot do? If you can't arrange to get one passenger in the back seat, you should plan to leave at least 1200 rpm. The power will help hold the nose up and give the elevator the authority required for a full stall landing. Very careful energy management will be required to avoid a balloon. It can be done to a full stall landing every time. You will not be able to see the runway. The nose wheel will remain well clear of the ground. Power can be applied for the takeoff and the flaps removed without the nose wheel ever touching the ground. Alternatively, the power can be taken off as the nose wheel touches.

If the C-172 is fully equipped with radios and panel gear, a full stall landing may vary from difficult to impossible depending on the seat position of the pilot. Landing with power at 12-1300 rpm as in a soft-field landing will make full stall landings easier. The C-172 lands better with a rear seat passenger.

Since CCR refueling practices avoiding fuel overflow, be sure to make an allowance for less than full tanks. A fuel tank will not hold as much useful fuel on a hot day.

A C-172 at a density altitude of 11,000' and properly leaned will only develop 98 horsepower instead of its 160 at sea level. We now have a C-172 attempting to takeoff with a C-150 engine. This is not a takeoff situation even leaned and suicidal with a rich mixture. With a rich mixture you would be pumping over 10 gallons an hour of fuel into a engine which for best power should only have 7 gallons per hour. You lose from an overly rich mixture in many ways. Wings and propeller cannot be turbocharged so their capability cannot be changed. CCR density altitude at 100 degrees F is 3000'. Plan and fly accordingly.

Exercise in C-172:
Go to slow-cruise of 90 knots and reset the attitude indicator for level. Cover the AI. Initiate a climb with full power and confirm that the climb is reasonable both in attitude and airspeed. Reduce power for slow-cruise and make a 15 second right standard turn. Level off and initiate a descent by reducing power. Level off by adding power. Make a 15 second turn to the left. Do this several times to develop a sense of control and safety. You will learn that attitude plus power gives performance. The had move in unison on the yoke and throttle to give the desired performance. From this proceed to develop the attitudes and power required to give you all the performance parameters required for all performance situations. You want to learn to control the airplane so that flying is not a part of the instrument flying equation. There is no one way to initiate, perform, and conclude a given maneuver. The following procedures are merely suggestive as one way.

C-172 Procedures and Landings
1. Abeam numbers, power back to 1,700rpm. Hold the heading and altitude.
2. Decelerate and trim for 70 knots.
3. 10 degrees of flaps, trim for 70 knots
4. 20 degrees of flaps on base. Trim for 70 knots
5. Turn final, flaps as required, trim for 60 knots.
6. Use power as the variable to control arrival.
7, Use rudder/ailerons to align with runway
8. Make small pitch corrections in the roundout.
9. Flair as the numbers go under your nose.
10.Keep holding a little back pressure
11.When you feel the plane starting to settle, raise the nose to cover the far end of the runway.

Precision Approach Speed No Flaps
Clearing turns
carburetor heat
Power to 1500
Hold altitude with yoke
Trim down as far as it will go
Power to 1800 for minimum controllable at 50 knots
Power to 2000 for slow flight @ 60 knots

Level Cruise
Full power until 100 knots
Power to 2450

Climb at 90 Knots
From level cruise
Raise nose to climb attitude
full power
One+ trim down.
Fine trim for airspeed

Level Approach Speed at 90 Knots
From level cruise
Power to 2200
One+ trim up

Level Approach Speed at 90 Knots #2
From Climb
Lower nose
Lower nose to level
At 90 knots reduce power to 2200
Fine trim

Descending Approach Speed at 90 Knots
From climb
Reduce power to 2000
Lower nose to descent attitude
Fine trim for airspeed

Approach Descent Speed at 90 Knots
From level approach speed
Power to 20000
Fine trim

Slips with Flaps
POHs 172

The owners manual for the 1967 Cessna 172 states on page 2-11
Normal landings are made power-off with any flap setting. Slips are prohibited in full flap approaches
because of a downward pitch encountered under certain combinations of airspeed and sideslip angle.

The 1976 POH requires a placard which states "AVOID SLIPS WITH FLAPS EXTENDED"

Landing section for Normal landings states:
"Steep slips should be avoided with flap settings greater than 20 (degrees) due to a slight tendency for the
elevator to oscillate under certain combinations of airspeed, sideslip angle, and center of gravity loadings."
"The maximum allowable crosswind velocity is dependent upon pilot capability rather than airplane
limitations. With average pilot technique, direct crosswinds of 15 MPH can be handled with safety." No
max demonstrated crosswind speed is in the POH. The 1967 model has 40 degrees of flaps available.

The 1970 (C172K) model's POH (1970 model also had 40° flaps) has been changed to read "Slips should be avoided with flap settings greater than 30° ..." No required placard is noted in the Limitations section.

Placards are required by model:
According to the TCDS 3A12 (covering models 172 - 172S), regarding slips, the following On flap handle,
Models 172 through 172E:
"Avoid slips with flaps down."

Near flap indicator Models 172F (electric flaps) through 17271034, excluding 17270050):
"Avoid slips with flaps extended."

The 172 manuals suggest, but do not restrict, not slipping the aircraft with more than 20 degrees of flaps. On that model doing so would occasionally induce "elevator oscillations." No such notation appears in the 182 POH, or the POH of any other model Cessna besides the 172, because no such elevator oscillations have shown up in full flap slips on other models. Probably has something to do with different fuselage lengths and tail sizes.  Having intentionally gotten a 172 in this configuration in my flight instructor days, I did after much effort, get some elevator oscillation. No big deal, just some momentary change in stick force at the control wheel. Plane remains fully controllable, however, I can see where it would be disconcerting for the pilot, particularly if it occurred during the landing flare. But again this only applies to the 172.
John Frank, CPA Tech Rep

Landing Problem (Opinion)
I had the plane trimmed for landing, and I was seemingly pulling with all my might to flare. Is this normal?

I've got about 800 hours in a 177B and a 177RG and I'm a bit puzzled by your problem with high flare forces. The main difference between the Cardinals and other Cessna trainers is the stabilator. At high speeds, trying to overpower the stabilator if it's out of trim will require huge yoke forces, but at flare speeds it gets much lighter. My thought is that you were coming in hotter than you may have realized and that the plane was not trimmed quite right. I find that if I get the plane slowed down to 90ish KIAS and level in downwind with 10-degrees of flaps out, and get a decent trim setting for that configuration, then the plane will almost fly itself down through the rest of the pattern through a power reduction and subsequent additions to flaps, with only minor trim adjustments required.

So theory 1 is that you were actually too fast on final and not really trimmed right.

Theory 2 is almost the opposite: you were trying to impress your instructor by flying a nice slow short-field approach with 30-degree flaps. You were in a significant nose-down angle and tried to pull it up at flare to the stalling pitch all in one fell swoop at minimum airspeed, just as the stabilator is losing the last of its power. The yoke is in fact very light in forces, but you're actually so tense trying to horse the heavy nose from its steep nose-down to a stalling nose-high pitch in two seconds that you've got the yoke against the stops, which feel darn heavy :-)

Theory 3 is that the stabilator bearings, cable pulleys, or antiservo tab on the stab need maintenance; it does sometimes happen that things do wear out in only three decades :-) (As a side note, all early Cardinals were "recalled" to get the stabilator slot mod mentioned by another poster, so that's really only an historical curiosity.)

Anyway, my suggestions are:
(1) Trim it out nicely on downwind, when you've got your speed stabilized at 85-90KIAS or so.

(2) Initially work on landings with 20 degrees of flaps. This doesn't get the nose as far down, so makes for an easier transition to nose-high landing attitude.

(3) Watch your airspeed like a hawk on final until you're 10-20 feet AGL.I suspect it's easier to pick up a little too much airspeed on short final in the 177 than the 15X you're used to. Conversely, if you get too slow, the 177 will sink pretty fast even if you're not near stall. I like 65-70KIAS on final with the FG, about 5 more for the RG. You'll have to adjust these speeds to MPH if you've got a pre-1976 Cardinal. Work on the slower short-field approach after you're happen with the normal landings.

(4) If you can't take your hand off the yoke and fly with the rudder any time during a straight segment of base or final, the trim, power, and airspeed must not be right. It should be two fingers' yoke pressure until the flare.

(5) Make a distinct separation of the roundout and flare. For the roundout, pull up just enough to break the glide and fly the plane level down the runway at a height you're not afraid to fall from, somewhere between one and six feet depending on how good your depth perception is. Lower is better, as long as you don't whack the nosewheel first, but don't worry too much about being a little high as long as the stall horn isn't tormenting you. Freeze your stabilator pullback position to fly flat until the plane slows. You should have all the power eased off no later than breaking the glide unless you are attempting an honest-to-God soft field landing, and probably even then.

(6) Wait for the plane to slow and start sinking before you pull back any more. As the plane sinks, ease in more up-stabilator to try to keep the plane at the roundout height. When the plane gets tired of flying, it will land on the main gear, which is the whole point. Drop the nose gear whenever you like. Voila! You've flared and landed. The stall horn may or may not be busy at this time, depending on how high you want to point the nose. As long as you touch down on the main gear first on a paved runway, it's mainly a matter of taste.

Some people like to dial a bunch of nose-up trim for flaring; I don't touch it after entering short final and usually it ends up close to the take-off trim setting, fairly neutral for around 70 KIAS. As another person mentioned, if you do use a lot of up trim, be prepared to demonstrate some good tricep muscle on a go-around. You'll have to do it one handed too, since the other hand will be spinning the trim wheel like a top :-) I prefer a neutral setting, but it's a matter of taste.

Once you've broken the glide and stabilized the plane level above the runway, NEVER EVER PUSH THE YOKE FORWARD. If you have pitched the nose too far up and it's ballooning up, GO AROUND and do better the next time, don't push it down like you can get away with in a 172. The nose is heavy and the stabilator is big and powerful and if you get the two working the same way you can do amazing things to the nose gear, none good, as you porpoise down the runway. If you've got it up just a little too much, freeze the yoke back-position (it's still fair to use your ailerons, of course), and wait for the plane to slow down and settle. I slammed plenty of 172s into the ground as a student pilot, and I honestly think the Cardinal is an easier plane to land once I got the trim and airspeed calibrated on final and abandoned my old 172 flare technique of yanking the elevator back to the chest in one swift motion as soon as I saw the instructor tense up and start to reach for the yoke.

As you get more experience with the plane, it will be easier to blend the roundout and the flare together, but even now if landing conditions are marginal, e.g., gusty winds, I will round out and fly the plane a few feet above the runway to make sure I'm happy that things are under control before committing to the flare and landing.

I hope you find these suggestions helpful. I think the Cardinal is a great plane (though a turbo and/or another (fillintheblank) HP would be nice too) and a decent cross-country vehicle. And if you get a few more hours and still think the yoke forces are superhuman, maybe somebody should look the stabilator mechanicals over. One of the major problems with Cardinals is that there are more than a few mechanics who think that everything put in a 177 must be just like a 1X2, so why look at the service manual? You could buy out Bill Gates with the money that's been spent to replace FG shimmy dampeners that have exploded after getting topped off with fluid, ala 172s. :-( Luckily, that's only fatal to wallets, not pilots.Good flying,

Second Opinion
The 172 is not easier to land -- it is different. It has a distinctive tendency to balloon if your approach speeds are too high. The greater weight gives a more solid feel to the plane, but to be honest I really don't think there is all that much practical difference between the two planes.

The 152 is not dangerous in spins. A few hysterical chicken littles, notably on this ng, have gone overboard on a 152 in Canada that crashed during a spin. This 152 was missing several parts that had been removed by a mechanic who didn't think they were important. Inspection of other 152s at that same school revealed that most of them were missing the same parts (what a surprise). This mechanic had worked on 152s elsewhere and they had been similarly modified -- so the Canadians issued an AD requiring all the 152s in the country be checked. The FAA in the USA works the same way. If someone cuts their finger, everyone has to take their fingers in to be checked to see if they are bleeding.

The 152 is probably one of the safest aircraft in the world when it comes to spins. It would be hard to argue that the 172 is any better. In any event, spins are the least of the problem if you are looking at the relative safety of a type of airplane. Both the 152 and the 172 have a long list of airworthiness directives. Most of these directives were probably issued as a result of a fatal accident. Yet these planes have a fatal accident rate per 100,000 hours that rivals that of airliners.

The 172 is a lot less tolerant of overloading than the 152. The small Cessnas in general have a large envelope, but it is possible to get them out of balance with just two people in front. The bigger the Cessna the worse the problem seems to be until in the 206 people take to loading weights in the back to keep the cg in limits.

Of total accidents both fatal and nonfatal caused by a stall (including spins), the 172 has almost the best rate of any plane, with 0.77 accidents per 100,000 hours. The 150/152 is about twice that at 1.42; still very good when you consider that both these planes are used extensively as trainers. Considering the people who fly them, the 152 does very well indeed, as does the Tomahawk and other 2 seat trainers of the period. They were a tremendous improvement over the Cubs which had accident rates that were more than five times greater. All the planes that are better than the 172 are also Cessnas, except for the Bellanca 14-19 and the Piper PA-32. The plane with the best record in stalls is the Cessna 182 at only 0.36 accidents caused by stalls per 100,000 hours, followed by the 195 at 0.47 and the 206 at 0.54. Compare this to the Aeronca 7's rate of 22.47 and a rate of around 5.0 for most Piper taildraggers.

Both the 150/152 and the 172 generally are near the top of the class in any category of accident, whether engine or airframe failure or bounced landing. The 172 probably has the best safety record of any general aviation plane ever built, but the 152 and the Piper PA-28 are not far behind. When these planes do have accidents their fatality rate is exceptionally low. The huge majority of accidents in these planes are simple fender bender types, with a good sprinkling of botched landings -- these planes are trainers after all.

Many people believe that trainer aircraft such as the 152, the 172, the PA-28, the PA-38, etc., were made deliberately hard to fly in order to make better pilots. I would like to see some evidence of this. These planes are so easy to fly that they have made pilots of many people who would never have otherwise been able to fly. Until these planes were introduced only an elite few had the talent necessary to make the cut. They put flying in reach of everyone, and for awhile up through the 1970s it looked like aviation had reached a critical point where someday learning to be a pilot would be an expected skill of everyone, like driving a car. Many factors conspired to end that dream, and the number of pilots being produced today is only a fraction of what we once turned out. Our numbers are increasing, but it will probably be many years before we return to anything like those days.

We pilots today are like pioneers, the forerunners of a generation when some day aviation will have truly fulfilled its promise.
C.J. Cambell

Fuel Problems of Cessnas
Significant fuel imbalance has been explained away as due to overflow venting pipes being pressurized by air
in flight. However, it has been found to be due to fuel tank sealant obstructing fuel tank vent lines as well.
See Cessna service bulletin SEB 99-18

C-172R Data Sheet
Vso 33
Vs 44
Vfe 30° 85
VFE 10° 110
Va 2450 lb 99
Va 2000 lb 92
Vno 123
Vne 163
Vr 55
Vx 60
Vy 70
Climb 85
Short field T/O
- flaps 10°
- slightly tail low
- init climb at 57
Max Glide 65
No flaps 70
30° flaps 65
Short Field 62
Lycoming IO-360, 160 hp @ 2400
Fuel: 100 or 100LL, 56 tot, 53 gal usable, 35 gal at tabs
Oil: 6 to 8 qt
Power settings TAS GPH
Take off FT/2400
Cruise climb 2400# 85 11.0
4000 ft 79% 2300 117 9.1
66% 2200 111 8.1
6000 ft 80% 2350 120 9.2
71% 2250 114 8.1
8000 ft 80% FT/2400 122 9.2
76% 2300 116 8.2
10000 ft 72% FT 118 8.2
12000 ft 69% FT 117 7.9
Lean 50°F rich of peak EGT

Clean 2100 90 level
10° flaps 2300 90 level
(precision desc) 1900 90 500 fpm
(non-precision) 1500 90 1000 fpm
In pattern clean 1900 85 level

A Better Way to Move a 172
Now that we are encouraging members to push the plane to and from the fuel and pre-heating stations to save starting wear and tear, we need an easier way to move it for the solo pilot. Even if you don't have arthritis in your hips, struggling with the too short tow bar is a pain. This method works the nuts.

There are now two 48" long loops of 3/16" bungee cord on the towbar handle and a length of rope. Put the towbar on backwards, hook the loops around the step on the landing gear, and run the run the rope over to the other side where you push on the strut. Pull to steer one way, release to steer the other. Tight turns are only possible in one direction so think ahead which side you want the bungee on.

This setup works even better in reverse because you aren't working against the trail of the gear.You can back the plane precisely into the tie down from out to the side where you can see. As a bonus, the tension of the bungee keeps the towbar from popping off.

The geometry just happens to work our for our tie down such that the plane will track right towards the pre-heating spot with no steering required if you put the bungee on the passenger side. A slight pull when you get close to the hanger and, you are there. There is a spare bungee in the milk crate.

Cessan vs Piper
--Seat belt systems are somewhat different.
--Flap relationship to trim is unique one from the other.
--Best to have your own POH for every aircraft you fly.
--Most of the checklist items will have a different sequence
--The first item of your emergency checklist will be different.
--Manufacturer's instructions related to carburetor heat differ.
--Night and cockpit lighting systems require distinctive explanations.
--The maneuvering and taxiing blind spots are usually quite different.
--One door system is more likely to accidentally open as the other is.
--Cross wind and ground handling in strong winds distinctly different.
--One flap system is more controllable and consistent than the other is.
--Seat adjustment systems are just different enough to cause difficulties.
--Never plan to immediately fly hard IFR in a newly transitional aircraft.
--The way you hold your hands on the throttle should be quite different
--One fuel system is twice as likely to cause an engine failure as the other is.
--POH numbers and explanations vary year to year and even within the year.
--You should always make your own aircraft specific operational checklist.
--Confirm the 'neutral' position of the trim setting indicator with actual trim position.
--Learn all you can about the failure modes of all unfamiliar instruments in either type.
--Gear retraction and extension of one is less likely to give problems than the other is.
--The way you use the rudder pedals and brakes have a VERY dangerous difference.
--The preflights are distinctly different with differing critical points where mistakes occur.
--Get some pre-flight cockpit time for reading the POH and referencing the cockpit to it.
--Run the trim wheel all the way up and down, manually and electrically to become familiar.
--Within the same models of each manufacturer there are wide critical airspeed differences.
--Both manufacturers have made wing, elevator and instrument changes affecting critical speeds.
--Distinct differences in handling when at gross and near either end of the center of gravity range.
--With two exceptions, one type is more likely to have a stall/mush accident in all its models than the other is.

Aircraft Proficiency Checkout
Removal and storage of cover
Checking time log/pitot cover and control lock storage
Cargo doors not to be slammed.
Refueling procedures
Location of POH/weight/ balance and aircraft papers.
Cockpit lighting
Starting procedures
Priming without throttle
Prop-wash effects behind
Detecting carburetor ice
Taxi procedures
Mixture leaning
Power vs brakes
Controls set for wind direction
Facing wind or local requirements
Use of hand brake/foot brakes
Magneto check drop comparison
Clearing fouled plugs
Pre takeoff
Clearing the bases and final
Confirming power available
First power reduction at 1000'
Leveling off
Allow acceleration before power reduction|
Setting 75%, rpm and leaning
Trim and use of auto pilot (Operation and failure modes)
Heading and altitude control
Coordination of flight
Radio Procedures
Initial call to ATC and follow-up
Non-tower airport operations (Pattern operations)
Light systems
Steep turns
Slow flight
Stall recognition/recovery
Emergency procedures
Simulated engine failure
3 take offs and landings to include
No flap
Short approach
Short and Soft
Full flap go-around

Unorthodox Short field in C-172

Afterthought: You know, the 172 is really a short-field machine. My instructor, the little Napoleon who got off terrifying people on behalf of the IRS CID, made me slow down the 172 in the pattern and on landing to not far above the stall and drop the flaps to 40 when we had the runway made, and flare it just before touchdown just over the threshold. I learned a lot from that guy. I've heard other pilots of renown and credibility swear THAT was the way to land a 172. We took this 172 into short fields all over the Carolina hills, and I mean into some tight little sod fields. I like the bush pilots --- he was one. God, how I love those days!
Larry Smith 

Crash Landing Problem
I have always prided myself on ability to detect and solve training problems but can't put my finger on yours. I suspect the problem lies in several areas in this order.

--Your seating. If you are not setting your seat height properly so your eyes allow you to turn your head and see the bottom of the wing, you should adjust your seat accordingly. A couple of months ago I failed a club checkride because my seat was too low. I picked up on the problem and passed without any problem with my seat at the proper height two days later..

--I havenít flown the C-172S but my bet is that it has a fully complete radio stack. Most C-172's need a backseat passenger to make a power-off flare. A short field landing can be made quite well while carrying power You can even fly a bit slower with a steeper approach angle. If you are solo with your seat forward as I would fly at C-172 you are right at the forward edge of the C.G. range. When you have a forward C.G. and low airspeed the elevator can run out of sufficient 'authority' to raise the nose for a proper flare. This is why carrying some power into the flare helps. Once the nose is up into the flare you can slowly reduce the power for touchdown.

--Airspeed. If you are making your approaches using the POH numbers you are too fast if solo and even with two aboard. The POH numbers are for gross aircraft weights. For every 100-pounds below gross weight there is an allowable reduction in approach speed. This speed is called Vref land applies to every landing. and most other operations where weight is a factor. Suggest you go to my web site and review the C-172 info. The Vref figures you want may be in the POH. Otherwise you might search my web site for the formula.
Let me know if this helps or what you do to solve the problem.
Gene Whitt.

Thanks for a detailed response and a pointer to your web site. It's an amazing resource.

More specifically, concerning my bouncing problem, your suggestions make sense, but not quite. Seating and CG might be part of the problem, but I seem to be flaring just fine with power off on normal landings, after forward slips to landing, etc. with exactly the same seating and same weight distribution. It's only on short-field landings that I misjudge *something* and bounce hard. This happens fairly frequently, but not

I will try approaching at below-POH airspeed next time. My concern is that, at lower airspeed, once I chop the power over the threshold I'll drop even faster. Your email and the short-field landing procedure on
your web site seem to suggest keeping some power into the flare, while I was taught to have power on idle as soon as I am over the 50ft "obstacle".

I suspect my problem is due to some combination of very fast sink rate once power is off and insufficient flare, which is very frustrating, because this means that my mental flare image is somehow wrong on
short-field landings. After I am clear of the obstacle, I just try to fly the normal roundout and hold the aircraft off as long as possible just as I would do (successfully) for a normal landing, but instead I feel the
aircraft plop on the runway and bounce back into the air.
Thanks for your advice!


You gave me the clue to your problem. When you pull the power off the aircraft makes a quick drop. You instinctively raise the nose to stop the sink. Wrong! Any raising of the nose will lower your airspeed. Maintain your airspeed. May require lowering the nose or at least holding it constant. The airspeed is what you need to flare.

Of late, (2003) more and more primary instruction is taking place in modified C-172s.  The modifications are usually some combination of more horsepower, a tuned exhaust and only 30-degrees of flaps.  Little mention is usually made of longer and re-pitched propellers which increase the inherent P-factor of the more powerful engines.  

The sum of these modifications is an aircraft that performs differently in critical situations such as takeoff.. An out of trim modified C-172 is likely to become airborne at a much lower airspeed.  It will climb at a much higher angle and pull considerably more to the left.  Failure to hold a strong right rudder means that yaw is a force to be concerned about at high angles of attack. Landings are likely to be exposed to excessive float, ballooning and high pitch angles if the same approach speed is used for the modified C-172 as for the standard under-powered C-172.

 The tuned exhaust system eliminates back pressure in cylinders, allowing a greater volume of combustible mixture to replace exhaust gases. This creates greater engine efficiency and brings the engine up to its full  rated horsepower. Conventional exhaust systems impede the flow of exhaust gasses, reducing the torque of aircraft engines so that a 180 horsepower engine might develop no more than 160 or 150 horsepower.

With a tuned exhaust there are exhaust tubes for each cylinder that are equal in length rather than the standard unequal lengths.  They all flow flow into a common collector. This allows the engine to breathe at full capacity, saving fuel in the process. Most installations get power increases of  up to 23 horsepower.  This can mean 150 to 300 fpm increase in climb rate. 
The engines tend to run quieter and cooler with a  tuned exhaust. Feedback from owners has been positive and enthusiastic.

There's no such thing as free horsepower. But the tuned exhaust can increase the power of getting more exhaust from the engine with less turbulence.  Tuned exhaust systems scavenge an exhaust pulse with the suction created by the previous outgoing pulse. This effect makes a given engine more efficient by generating the same power at a lower fuel burn.

The stock Cessna exhaust  has four short exhaust tubes going into a common muffler. This fails to efficiently send exhaust from the engine. Unequal lengths of the exhaust tubes send pulses into the muffler where they impact an exhaust pulse that was just left another tube. The opposite forces cause back-pressure to build up in the muffler system  Exhaust from one cylinder can impact the exhaust from the other side of the engine. Any disturbing flow affects the exhaust out of the engine and the flow of the fuel/air mixture into the cylinders.  The fuel burn for the horsepower will be less due to the better breathing of the engine.

At full power the modified aircraft will use at least a half-gallon per hour more fuel.  Plan accordingly and run a series of consumption checks to modify your fueling practices. Power Flow is  limited by the standard fixed-pitch propeller.  You can expect 5-kt higher indicated airspeed with the standard prop.  Re-pitch the propeller to go faster.  Runway performance and climb will be significantly higher.  Expect a minimum 100 fpm improvement in climb speed.  The takeoff will be about four seconds quicker than usual and at least 230 feet less distance and happen at about 35 knots.. All of this with the same standard engine.

. The modified aircraft  could lean to peak and slightly beyond before engine roughness occurs, at indicated fuel flow was around 6.7 gph. At full throttle the difference was 2.4 gallons per hour, but we don't recommend aggressive leaning at power settings higher than 75 percent.  A tuned exhaust evens out mixture distribution.   The plane can redline rpm in cruise.  A 3 inch longer and re-pitched propeller is .required to avoid red-lining.  Heater performance is o.k. down to -10 degrees Fahrenheit.

Installations may require that a hole in the lower cowl to let a support rod support the muffler and, relocating the gascolator to keep flow away from the exhaust.  there is a 3-4# weight addition. 

What this means to the pilot is that a completely different method of flying the aircraft is required.  More rudder, more anticipation and greater re-trimming as is required in larger aircraft.  Even the airspeeds will be significantly different.

Modified C-172s
The modified C-172 with power flow exhaust systems have sufficient power to surprise the pilot and reach this stall before being corrected.  Do NOT trim for the flare as a safety measure.  The go-around performed with trim applied for the flare can be deadly.

The C-172 rudder was originally designed for a 145 engine.  With a 180 engine and a power flow exhaust system you are getting 200 hp.  This aircraft in flare and power applications will require considerable rudder. It does not pay to be rudder-lazy in a modified C-172.

Don  a CFI, Asks for 
1963 C-172 Suggestions
I would suggest some of the following.

If the C-172 has a stock 150h.p. Lycoming it is more underpowered for its weight than a C-150. This means that when reaching pattern altitude you must stay at full power for a considerable time for the aircaft to acellerate before reducing power. (Alternative is to climb 100' high and dive to reach cruise speed more quickly.) Suggest that you go to altitude and have students practice climbs of 500' to level cruise several times with the intent to reduce the amount of time it takes to be hands-off level cruise.

If the final approach speed is to be 1500 rpm, teach them to reduce power to 1700 abeam the numbers, Since this done at cruise speed the momentum of the plane will initially drive the prop before it slows to the desired 1500. Trim down three times using fingertip behind top button to pushing that button into bottom slot. Doing this will, if student holds heading and altitude, allow the plane to extend the downwind just the amount required for turning base at 80 mph. Put in the first ten degrees of flap and take off one finger-tip turn of flap as plane descends at 70 mph. Check with hands off controls. Turn base.

On base put in 20-degrees of flap and take off another turn of trim. Change base angle to adjust sense of high or low for turn to final. Turn final and put in full flaps. No change in trim required. (Aircraft will be trimmed for Vy go around speed when flaps removed.) Approach speed will be 60 mph hands off.

Individual aircraft will vary this procedure but not by much. Back seat passengers will make significant change in yoke pressure required for landing flare. Still I suggest you do all lessons with two students and recorders (See my site) With due care you can change student seats in the air at altitude. Practice on the ground. This will allow one student to watch a lesson and apply it to his lesson.

Note that the 1963 wing does not have the 'cup' that later models have. Presume your flaps are non-electric. Makes for great landings and flight path control. Great year, great airplane.  You may find that solo students of light weight are unable to get the nose up at 60 mph. Try, as I did, a sack of cement in the luggage compartment.
More if you wish....

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Continued on C-182s