dewitte@bgsuvax.UUCP (Anne Dewitte) (10/30/85)
In the 172 that I rent I noticed my take-off r.p.m. was only 2200 which is just the beginning of the green arc. I had 3 others in the plane and was getting a bit nervous. I learned from the mechanic that the engine is a 0-320-H2AD and it is a piece of (junk). I'd like to know what other's take-off r.p.m.s. Is it this particular engine or characteristic of all 0-320-H2ADs?
cfiaime@ihnp3.UUCP (J. Williams) (10/31/85)
In article <769@bgsuvax.UUCP> dewitte@bgsuvax.UUCP (Anne Dewitte) writes: >In the 172 that I rent I noticed my take-off r.p.m. was only 2200 which is >just the beginning of the green arc. I had 3 others in the plane and was >getting a bit nervous. I learned from the mechanic that the engine is a >0-320-H2AD and it is a piece of (junk). I'd like to know what other's >take-off r.p.m.s. Is it this particular engine or characteristic of all >0-320-H2ADs? If you watch the RPM on any fixed pitch prop airplane, you will notice that takeoff and climb rpm is somewhat less than red line. It seems that with the pitch of the prop on a 172, it is particularly noticable. BUT, 2200 rpm is a bit low. At that point, if concerned about the engine, I would have aborted the takeoff and had the mechanic look the engine over. When in doubt, DON'T FLY. As for the O-320-H2AD itself, this is not one of Lycoming's better contributions to aviation. Early ones had valve lifter problems, oil pump problems, and (I think) cam shaft problems. This lovely little engine :-) was so reliable that in 1978 all of the engines were grounded pending inspection. We had one that had under 3 hours from the factory and needed replacement. (I was working for a ferry service in Wichita at the time.) Another problem with later Lycoming designs in general is the wonderful invention of the "twin pack" magneto. Let's face it, gang, a mag typically dies because of a mechanical failure in the drive, not an electrical failure within the mag itself. Sure, Eiseman mags blow condensors, and old Case mags may have swollen rotors, and there is an AD on the coil in old Bendix mags, but MOST OF THE TIME the failures are in the nature of a broken drive. So what does Lycoming do? Sure, a common drive for both rotors. You lose the drive, you lose all spark in your life, so to speak. Don't you love what companies do to save a few dollars in production costs? jeff williams ihnp3!cfiaime AT&T Bell Laboratories
wool@oracle.UUCP (Chris Wooldridge) (11/03/85)
In article <769@bgsuvax.UUCP>, dewitte@bgsuvax.UUCP (Anne Dewitte) writes: > In the 172 that I rent I noticed my take-off r.p.m. was only 2200 which is > just the beginning of the green arc. I had 3 others in the plane and was > getting a bit nervous. I learned from the mechanic that the engine is a > 0-320-H2AD and it is a piece of (junk). I'd like to know what other's > take-off r.p.m.s. Is it this particular engine or characteristic of all > 0-320-H2ADs? During climbout in fixed-pitch propeller airplanes, reduction in RPM is quite normal, for the same reason prop overspeed can occur in descent if you don't throttle back. As for the engine, your mechanic is quite right. Cessna used the "E" series of the O-320 until about 77 (I think) when they switched to the "H" series ... which seems to be about the only "bad" engine Lycoming has ever produced. A faulty valve and valve train design causes the engine, which has a recommended TBO of 2,000 hrs, to burn out quite a bit sooner - sometimes as little as a few hundred hours. Cessna recognized this and switched back to a "D" series enginea few years later which has been quite reliable. There are about 8,000 of these "H" series engines out there, so if you're Skyhawk shopping make sure you check the engine carefully. Since your airplane is a rental, a valve problem in the engine should be detectable at the 100hr inspection as low compression on one or more cylinders. Check the engine logbook for the figures from the last 100 hr. Happy aviating ... (heard last Thursday night before starting a bumpy approach ...) "Boeing Field Information Transylvania, 0500 greenwich weather, measured ceiling 700' overcast visibility 2 miles rain, fog. Wind 160 at 10 gusting 15, altimeter 30.12. Approach is ILS to 13R. Advise ground or Seattle Approach you have information Transylvania ... AHHH OWWWWWWW!!!!" -- Chris Wooldridge Oracle Corporation 1100 206th Avenue, N.E. Redmond, Wa. 98053 (206) 868-1985 {ihnp4!muuxl,hplabs}!oracle!wool
ths@lanl.ARPA (11/04/85)
> In the 172 that I rent I noticed my take-off r.p.m. was only 2200 which is > just the beginning of the green arc.... I'd like to know what other's > take-off r.p.m.s. Is it this particular engine or characteristic of all > 0-320-H2ADs? I recall very vividly the first time that I noticed the RPM during take-off in a C-172 (O-320-E?). I too was at gross and was a bit concerned at the long take-off roll. I glanced at the RPM and.....WOW ONLY 2200! Since I was on the LOONNGG runway at Stockton Ca. I continued the take-off (amazing how the neophite pilot will go where angels fear to tread!). When I returned to Reid-Hillview I asked my instructor "how come"? He said it is that way all the time but he either failed to point it out to me or I failed to note his comment during the check-out. I had about 70 hours at this point and it was my third or fourth flight in the C-172. As with most experiences of this type it stayed with me. Today I make a definate point of having my students check the rpm early in the take-off roll for 2200 to verify that they are getting the available power at that point. Carburator ice, bad mixture setting, fouled plugs, or carb heat left on will rob you of critical power. During the climb, at 70 to 80 knots the RPM will usually come up to 2300 to 2450 depending on altitude, climb speed and type of prop and engine condition. I don't know if there is a "climb" prop approved for the C-172 but that could increase the rpm by a 100. The only time you may see RED LINE of 2600 to 2700 (which represents 100% power at sea level) is during operations at low altitudes and full power or during high speed descents. The moral of this story Anne, is that fixed pitch propellors do not permit the engine to turn 100% RPM during take-off or climb operations. As a result the engine can not develop full power, a rather unfortunate situation since these are the two flight operations where you really NEED all the power you can get. This is why the "variable pitch" propellor came into existance. SEE THE ARTICLE IN AOPA PILOT MAGAZINE LAST MONTH - IT DESCRIBES THIS SITUATION VERY WELL. Ted Spitzmiller
ark@alice.UucP (Andrew Koenig) (11/05/85)
> In the 172 that I rent I noticed my take-off r.p.m. was only 2200 which is > just the beginning of the green arc. I had 3 others in the plane and was > getting a bit nervous. I learned from the mechanic that the engine is a > 0-320-H2AD and it is a piece of (junk). I'd like to know what other's > take-off r.p.m.s. Is it this particular engine or characteristic of all > 0-320-H2ADs? Light airplanes seem to have tachometers that read a little low -- at least the ones I've flown do. I suppose it's done that way so that prospective purchasers will believe the airplane is faster than it really is...
dhp@ihnp3.UUCP (Douglas H. Price) (11/08/85)
Now that it has been about a year since this incident (and I am now somewhat removed from it) I would like to relate what happened to me in a C-152 while still a <40 hrs. student. It was about a month and a half before my wedding, and I was trying to finish up my required flying time so that I could get my license out of the way beforehand. In fact, my instructor, Jeff Williams, often seen here in net.aviation, suggested, "You've got to get your priorities straight, boy! What's more important, flying or getting married?" :-) Anyway, I rented 6246P, a 1980 vintage C-152 with long range tanks for an hour's worth of practice area work. This airplane is equipped with a Lycoming O-235-L2C model four cylinder horizontally opposed air-cooled engine. I was the first one out that day with the airplane. Checkout was normal. It was a somewhat warmer day than the last time I had flown, so I was prepared for sluggish response from the craft, though not nearly as bad as we shall see. I was alone (of course) but had full long-range tanks, so the weight was relatively near gross. The following is what I remember was said between myself and the tower one year ago. Forgive any technical inaccuracies from the tower's point of view. I normally see it from the pilot's point of view. 6246P: Aurora ground, Cessna six two four six Popa at Luminaire with information Alpha, and I'd like to be westbound today. Aurora Gnd: Cessna four six Popa, Aurora ground, taxi to one eight. 6246P: Four six Popa. As I taxied to the active runway I could hear a rattle I hadn't heard before. But, then again, every time I got into one of those airplanes they sounded a little different. The power runup test was completely normal. 46P's engine had a tendency to silt up with carbon deposits which needed to be burned off by leaning the engine during the static tests. Nothing unusual was noted. 6246P: Aurora tower, Cessna six two four six Popa ready at one eight. Aurora: Cessna four six Popa, Aurora tower, right turn approved, clear for takeoff. I then turned onto the runway and applied full power. Acceleration was sluggish. I noticed this problem relatively soon in the roll down the runway, but didn't do the correct thing and abort the takeoff. Finally after using about 3/4 of the 4500 foot runway, I managed to get the thing into the air. Now, not only was acceleration bad, but the rate of climb was anemic at best. Groundspeed stayed low, the attitute to hold the airspeed was low as well, and the rate of climb indicator reported a 150ft/min climb. The expected value at that temperature and a 75kt airspeed would have been around 500ft/min. As it was I was doing well to maintain that rate of climb at the best-rate-of-climb airspeed 68 kts. Once I had assured I would clear the power lines on the other side of the road, I finally got around to checking the tachometer. It reported that I was at 2000 rpm, 300 rpm low!! So it wasn't my imagination! It was real trouble!! 6246P: Aurora tower, four six Popa, I've got a problem here. Aurora: Four six Popa, do you wish to declare an emergency, sir? 6246P: Uh, negative. I'm not developing full power, and I'd just like to get this thing back on the ground. Aurora: Roger four six Popa, can either continue in the pattern to the right, third in order for landing, or I can give you a left turn for landing on runway two seven. 6246P: Aurora, four six Popa, I'll go right. Aurora: Roger four six Popa. Another mistake. If there really was a problem with the engine, it might quit at any second. I might be better to take an immediate vector to a runway. On the other hand, diverging wildly from what I had planned in the first place, a right turn (which would allow me to continue around the pattern) could be just as dangerous for a low-hours student such as myself. As I waited until I had reached a safe altitude to begin a turn, I listened to the engine a while longer. 6246P: Aurora tower, four six Popa, I've changed my mind, I'll take the left turn. Aurora: Cessna four six Popa, left turn approved, clear to land on runway two seven. Cessna four one Popa, go around.... Now came the, ahem, fun part. Rule 1: when in trouble stay in tight to the airport; you may have to glide it home. Rule 2: in the case of suspected engine trouble, especially that close in, don't touch the throttle until you are fully committed to the runway. Jeff had told me that most engine failures on landing occur when power is reduced for the landing. My turn to the left (gently, gently!) put me on a slightly far-out downwind for 27. Still with the throttle all the way in, I turned base for a short final. The flaps started coming out at this point. Finally, when I had more than enough energy to make the runway, I cut power back to a normal 1500rpm value. The engine didn't quit. Full flaps and a normal-feeling crosswind landing. Aurora: Cessna four six Popa, clear to taxi, remain on this frequency until fully stopped. 6246P: four six Popa. I taxied back to the FBO. The engine sounded normal again!! 6246P: Aurora tower, four six Popa, back at Luminaire. Aurora: Roger four six Popa. I climbed (shakily) out of left seat, went to the owner of the FBO and said, "You might want to take a look at the engine..." I sat in my car for a while and thought about my actions. Two days later I dropped by to see what they had found. The AP had the right side of the engine apart. A crescent shaped chunk of the piston skirt 1/3 of the way around one of the piston was missing. The AP said that the piece had fallen back into the crankcase and had gone bouncing around in there. That particular cylinder was developing no compression at all. The one on the opposite side was pretty bad off as well, and the other two had been on their way downhill. He gave me a fuzzy polaroid photo of the bad piston, an extra from the report supposedly going to the NTSB. The usual "storal of the mory" is of course, anything out of the norm is worth worrying about! -- Douglas H. Price Analysts International Corp. @ AT&T Bell Laboratories ..!ihnp4!ihnp3!dhp
ark@alice.UucP (Andrew Koenig) (11/09/85)
> Now, not only was > acceleration bad, but the rate of climb was anemic at best. Groundspeed > stayed low, the attitute to hold the airspeed was low as well, and the rate of > climb indicator reported a 150ft/min climb. The expected value at that temperature > and a 75kt airspeed would have been around 500ft/min. As it was I was doing > well to maintain that rate of climb at the best-rate-of-climb airspeed 68 kts. Digging into my Cessna 150 manual, I note that it says that during a full-power runup, the engine should turn 2360-2460 RPM. While the tach may be off a few hundred RPM, it would probably be worth while to run the engine up to full power briefly before takeoff and remember how fast it turns. If it does something markedly different next time, you know something is amiss.
cfiaime@ihnp3.UUCP (J. Williams) (11/10/85)
It is interesting to see Doug Price's article about his engine failure. As Doug's instructor, there are several things that I can see I didn't stress enough in his training. 1. Never take a sick airplane into the air. 2. Always check your instruments (airspeed and tach/manifold pressure) on takeoff. 3. When in doubt, ABORT YOUR TAKEOFF. When I first heard about Doug's incident, I was pleased with how he handled the situation. I am still pleased. However, I feel that he should have said "emergency" when he realized that the airplane was in trouble. There is nothing wrong in telling the tower that you want special treatment if you have a problem. This incident reminds me of a happening in a 1940 Aeronca Chief (11AC) back in Chanute, Kansas. I was giving someone a checkout in this freshly rebuilt machine. On takeoff, we were using the short (less than 2500 feet) grass strip. The engine didn't sound right, like it was not developing full power. Slim Hunsaker, the owner, decided to fly anyway. At about 30 feet of altitude, the engine went to idle power. We landed before hitting the trees, and got the airplane turned around. Investigation showed that we were getting carb ice because of a missing baffle near under the engine. Not pleasent. Will I fly a sick airplane knowingly? Well, yes and no, depending on the airplane and the situation. I have ferried sick airplanes for rework, taking into account the possible damage to the airplane or the nature of the engine problems. Always solo, always daylight, always with a place to land. But, if an airplane develops problems on takeoff, abort. (The only exception to this has been in the Funk. Coming out of Millville, New Jersey, the radio smoked and died. In spite of the electrical smoke in the cockpit, I continued my takeoff while killing the master switch. I don't abort while l}eading a flight of 2 because the second airplane may not be in a position to stop.) Anyway, I am pleased that Doug shared this incident. What Doug doesn't relate is that when he and his wife are renting airplanes, they always break. Doug's wife is also a pilot (and a good one, at that). On one Saturday, we were going to give Doug's wife a BFR and also go out for breakfast. There was an alternator fire on startup in the first airplane, landing gear problems in the second (popped circuit breaker, pump ran all the time), and some other problem on a third airplane. I have gotten where I watch Doug fly from the ground. I already have enough grey hairs. Jeff Williams AT&T Bell Laboratories ihnp3!cfiaime