Ok, this might be the dumbest thing to ask, but how do you effectively hold your altitude in a fixed pitch airplane with all analogue instruments? I genuinely can’t figure this out.
I’ve only flew airplanes with CSP and digital instruments but recently I hoped in a C152 and depending on the weather I could be fluctuating up to 200ft +-. I did manage to complete the differences training in 2 short flights because the procedures and emergencies are super simple but for the life of me I can’t figure out how to fly straight and level with this thing.
The way I would maintain my altitude in a da20a1 or a p2002mk2 would be to note the attitude on the ah where the airplane flies level and maintain it and if I would have updrafts or downdrafts I would just pitch up or down and the CSP would maintain my engine RPM so my trim would remain the same.
My biggest struggles are reading the AI, the propeller RPM keeps changing, and the airplane keeps getting out of trim (because of the previous reason)
I really need all the advice, wisdom and tricks I can get.
You watch the altimeter, and hold the attitude that makes it stay put. It quickly becomes second nature once you get the feel of any given plane. And keep it in trim. Not a big deal in a 152, where the trim is pretty superfluous frankly, but in a 182 if you don’t keep it perfectly in trim you won’t be able to keep it level (unless you are a bodybuilder).
Real planes don’t have AIs (OK, that’s a bit strong – but you should be able to fly a Cub or Citabria, which don’t).
I learned how to fly in a plane with one Venturi driven gyro instrument, no AI, and essentially my only use of an AI now is in occasional hood work, for IMC practice, rarely do I look at the thing in my normal flying. An AI has nothing to do with ‘classic VFR flying’.
You only need one instrument to hold cruise altitude, the altimeter, and one control, the elevator. With a FP prop in a light plane (not a 182), if you sink below desired altitude hold a little aft stick/yoke pressure for a while, and do nothing else except be patient. Allow speed to decay a bit while slowly regaining the lost altitude. Don’t mess with trim, leave it as set for cruise AoA. Once you get back to the desired altitude let the stick pressure relax and the plane will return to cruise AoA and RPM. Do the opposite (light forward stick pressure) when floating a little high. Don’t try to hold constant RPM with the throttle, set the throttle for cruise RPM once and then leave the throttle where it is along with the trim.
Meanwhile keep the ball centered with your feet and the plane won’t change heading.
@JoeMama_the_Pilot wrote:
how do you effectively hold your altitude in a fixed pitch airplane
Just turn on the autopilot! 😂
The options discussed by @johnh and @Silvaire will help you maintain altitude. But when flying in an aircraft like that, presumably VFR, why bother keeping your altitude exact? If you get an updraft, ride it! The quickly upcoming downdraft will bring you back where you were…
But when flying in an aircraft like that, presumably VFR, why bother keeping your altitude exact? If you get an updraft, ride it!
This is the answer, unfortunately it will not impress any flight instructor or examiner…
Worth a read in this regard:
https://en.wikipedia.org/wiki/Phugoid
I have the same issue, just exacerbated that the phugoid oscillation is unstable in my plane – gliders are notorious for their low damping. So, basically, you can’t really let go of the stick while under power.
Fun fact: A week ago an aquaintance had his second birthday. This is all preliminary, I understand he wanted to fly to an airfield festival and went half comatose due to exhaust fumes entering the cockpit. The controller told him later he “watched him die” when the perfectly trimmed plane flew in a phugoid for an hour, including through a control zone, changing course at random until he came to enough to land.
The C152 (I did most of my PPL in them) is fairly stable but does need practice to fly well.
Fixed pitch prop planes are less stable in pitch because the engine revs vary to make pitch excursions worse.
Your brain is a much better AI than you think (pretty stupid thing to say in these AI infected days 
, thinking of the “other” AI). But it has to be trained. Not much training is needed though. 2-3 hours max and you got the hang of it. All you need to fly straight and level is the altimeter. It’s in fact perfect for it, not so fast reacting as a VSI which, just makes it more difficult. The other “trick” is one hand on the throttle and keep that RPM constant.
I trained a lot of air force cadets. They were used to SAAB Safari with CS prop and proper AI. The only thing I needed to tell them was to work that throttle. They got in within one single flight. The “correct” way is to look outside, use your ears to get the RPM right and glance at the altimeter every now and then. It’s no problem keeping the aircraft glued to the correct altitude.
The other side of the coin is what eurogaguest say: Why ? Flying cross country VFR it’s a very stupid thing to work against the winds. You will use them to you advantage, and that means changing altitude while keeping the airspeed fairly constant.
You have been studying lots of aeronautical equations I have seen. The brain works very much like a PID controller, only it’s much better. It has several feed forward loops, several feedback loops (for every parameter), and it can change the PID constants continuously and at will while also being predictive in both short and long time frames. It’s more of a sensor fusion predictive flight control computer, but the basic PID algorithms is the foundation. To make it work satisfactory, these PID algorithms have to be in muscle memory. The only way to train muscle memory is to exercise.
If you think of it like that, there will be at least 3 integration constant when keeping level flight. A very short one using the VSI. A “normal” one using the altimeter, and a very long one flying cross country. The very long one is not as much muscle memory as it is predictive modelling.
LeSving wrote:
The other side of the coin is what eurogaguest say: Why ? Flying cross country VFR it’s a very stupid thing to work against the winds. You will use them to you advantage, and that means changing altitude while keeping the airspeed fairly constant.
For Romania I would say it is probably true, for the UK – no way, see all the talk about the CAS infringement.
Go and fly this aircraft on a cool windless evening and you will quickly learn these things fly beautifully despite being basic and slow.
Once your brain has experienced it, you will subconsciously learn a chunk, and have more confidence it is a stable platform.
After that, a little extra eye on the ALT and you’ll be able to do it in less stable air.
However as mentioned, unless in a test, fighting for absolute altitude all flight, is unnecessary and hard work.
When I was learning this struggle was a familiar thing to me also.
I flew up and down and lost heading often depite trying to diligently watch the instruments and was convinced it was impossible to to keep the tolerances the instructor wanted.
He would say “my controls” and ‘The flying Gods’ would turn off the turbulence, wave and crosswinds for as long as it took to say “Your controls” before turning them back on, to make me look bad.
