First helicopter lesson: questions?

[baobab72]

Hi everyone
today i had my introductory lesson at flying the helicopter - an R22 -, loved it!! was so excited that i almost forgot my bag under the seat and a few questions i wanted to ask the instructor but that start to emerge back only now!

let me bring to your attention that the flight took place in cannes and all the checklists were in french which is not my first language, so even though the instructor talked me through most of the procedures, a few words did get lost in the translation!! besides some portions of the flight are still a blur!!

a few considerations for the plank drivers outthere willing to give it a try!

checklists pretty straight forward, it all makes sense if you have done some reading on rotorcrafts - although the start up happens very quickly, the instructor turned the alternator on at a very early moment during the start up sequence so i was wondering what the proper procedure is - how long do you have to wait? - followed shortly after by the clutch, as reflected by the erpm's and the rrpm's increasing as the clutch was bringing the main rotor online. i believe that he checked the oil pressure and then we waited for the CLUTCH light to extinguish. Once the light went out he increased the engine to 70% and then he checked the magnetos - max drop 7% within two seconds - the carb heat - he pulled the carb heat lever and checked for a decrease in ermp's and for an increase in the carburetor temp gauge, the sprag clutch - didn t quite grasp that check, too quickly so if anyone is willing to shed some light on that it would be much appreciated!!!, he just wound the engine down and checked for the erpm and the rrpm needle to split, indicating that the rotor had been disengaged from he engine; and something else i can not recall.

he then briefed me about some power settings that we were going to use - 21"Hg MAP for cruise, 23 for the climb abd 18 for the descent, he also mentioned 15 but i forgot to which phase of flite it applies.

once the takeoff clearance was issued, he picked up the aircraft to o hover, it happened much faster than i had anticipated, while i was following him on the controls, and in a bit we took off heading towards the shoreline - i was still trying to figure out when we would have experienced the ETL so i missed most of the takeoff!! lol although i think from a hover he held the collective steady and then he pushed the cyclic forward to accelerate to whatever speed and then we took off!!

soon after takeoff he handed me over the cyclic and at first although all the readings i had done on the subject and on the flying techniques that apply to the r22 i did try to correct for a right bank by raising the cyclic!!! he then told me that what i was doing had no effect on the controls so the first lesson learnt was that in order to turn you have to move your wrist horizontally if you wanna control the helicopter, in the direction of intended movement!

thanks again to your advices and my readings i did nt fall in the overcontrolling trap, althogh i constantly had to tell myself to relax my grip!!
i looked outside and i took a point slightly above the compass as a reference to maintain my horizon and it worked just fine, i was able to maintain my altitude within 50 ft or less!

one tendency that i had was to pull the cyclic towards me while entering a turn trying to compensate for the decrease in the vertical component of lift but that comes from my airplane background even though during the second portion of the flight what the instructor was telling me finally did sink in and i was correcting with the collective.

I had an hard time to adjust to the fact that you mainly control your direction of flight and airspped solely by the cyclic and not much your altitude so everytime my altitude was shifting i was trying to correct for it by using the cyclic instead of the collective!!

also during the approach i had a very hard time to control the helicopter despite of the hints from the instructor - or i should say i had a hard time following the instructor since i was still trying to grasp the relationship between the cyclic and the collective!!

during the approach i had a hard time adjusting to the fact that pulling the cyclic will cause the airspeed to drop and it is a very odd feeling looking at the airspeed bleed away!!!

then it came the hover: at first he gave me the cyclic and although it was not pretty i did not drift as much as i had anticipated, while once he gave me the pedals and the cyclic i couldn t figure out what the helicopter was doing and which control i was supposed to use to correct it - the instructor told me that i was trying to correct for a heading change with the cyclic although i should have used the pedals but quite frankly even now, i can not tell you if the airplane was yawing or turning or both, i was just not able to eep it under control!!!

overall a very good experience!!

now the questions:

the instructor told me that with the collective we control both our altitude and ourmap: i understand the altitude portion, but not the map one!!! is it because of the correlator? why when you raise the collective your map increases? and why when you lower it it decreases?

when do you use, if you do, he ermp/rrpm gauge? other than during start up?

during the approach what do yo use to control your rate of descent? is it the collective?

what are the power settings that you use?

Many thanks!!!

baobab72

[FSXPilot]

The governor controls your RRPM. So lifting the collective has the effect of increasing the angle of attack of your main rotor blades. This also increases drag so the governor asks for more power from the engine. MAP is the power the engine is producing.
I hope that helps explain some of your questions.

[baobab72]

Tks for the reply
So if for instance i want to start a climb i raise the collective, the blade picth increases, the aoa increases, more lift, the rotorcraft climbs.
As the lift increases so does the induced drag, therefore the rrpm's tend to drop, the governor kicks in and increases map to maintain the proper rpm's. How far do i pull the collective? Until my roc is achieved? And the throttle do i use it to fine tune the required map of 23? And then i use the cyclic to pitch for the desired speed of 60 kias, am i correct?

Tks

Baobab72

[MartinCh]

B72, you may want to resurrect heli aerodynamics thread or start your own.
It's gone way off topic/name of this thread.

Oh, btw, I know that due to your aviation background, you want to have things clear, but you're way ahead of flight portion, from briefly skimming through your posts. Not to mention the MAP setting is rough guide, which changes with conditions, total weight of helicopter, IAS desired etc.

Welcome to helicopter community, btw. I also fly planks and gliders, so I'm not condescending pure heli pilot, haha. Just that flying rotary tends to be more fun, but also one has to be more careful as more things can go wrong. But for time being, you got the FI next to you to watch out for that and train/mentor you.

In R22/44, you leave 'fine tuning' of throttle to governor, so long you're not doing abrupt inputs to collective or restricting the movement of throttle by governor. You'll be concerned with throttle on start up/shutdown and practising for emergency, ie autos, hover autos, stuck pedal running landing, (GENTLE) low rrpm recovery practice etc.

[Ascend Charlie]

To answer your questions:

the instructor turned the alternator on at a very early moment during the start up sequence so i was wondering what the proper procedure is - how long do you have to wait?

The alternator is turned on almost immediately, so that the battery isn't providing the electrical power for the clutch and other things.

the sprag clutch - didn t quite grasp that check,
Just a check to make sure the freewheel unit is working - the rotor has to disengage from the engine if the engine has stopped or is going slower than we want the rotor to turn.

the instructor told me that with the collective we control both our altitude and ourmap: i understand the altitude portion, but not the map one!!! is it because of the correlator? why when you raise the collective your map increases? and why when you lower it it decreases?

You already got that one. You want more pitch, you raise the collective. The lift is created, but the drag wants to slow the blades down. The governor opens the throttle to keep the RRPM steady, the MAP goes up. There is also a mechanical correlator which physically opens the throttle as the lever is raised, and this is then "topped up" by the governor. Same when descending, less drag, blades speed up, engine power gets reduced to control RRPM in green.

when do you use, if you do, he ermp/rrpm gauge? other than during start up?
You always keep an eye on the dual tacho, to make sure the revs are matching. In auto, the pilot must control the RRPM with collective to keep the revs in limits. Too fast, you will damage the rotor head and die. Too slow, you die. Just right, you live.

during the approach what do yo use to control your rate of descent? is it the collective?

Attitude (cyclic) is airspeed, power (collective) is rate of descent (or rate of climb, or staying level). On final, from about 300' and 60 kt, with the intended landing spot about halfway between the horizon and your instrument panel, you set the hover attitude, which gives you a gradual slowing down, and reduce the power to hold the aim point steady in the window. Maintain an apparent walking pace over your toes. Around 30 kt the drag rise makes you want to sink more (use power) and around 15kt you lose translational and want to sink some more. Use power as required (stay straight!!) to carry yourself to the landing spot. Easy.

[baobab72]

Hi guys
First of all thanks for your replies! And i do agree with the previous post about the fact that perhaps i am overthinking cos i am trying to get the whole picture without having the elements - it is not easy being a line training captain struggling to keep up with a flying machine, trying to connect the dots, keep a good situational awareness, and understanding the mechanics behind every and each input and maneuvers, but i guess i will have to adjust to the idea!!!

But i have this disease called compulsive curiosity!!!! :}

Coming back to the handling of the helicopter, let s say if i was want for instance climb, is it a true statement that initially raise the collective increasing the pitch, the correlator kicks in to increase the map and i keep on raising it until the desired power setting is achieved? Or do i use the collective to achieve the proper rate of climb and then i adjust the throttle to set the climb power? In the meanwhile i adjust my pitch to maintain the airspeed? In the plank world i use to teach the mantra pitch power and trim, meaning that first you set a desired pitch then you set the required thrust and finally you trim.
What would be the procedure to lets say start a constant speed climb at 500fpm and what is the one to level off?

I have searched the forum but i couldn t find any post explaining the sheer mechanics of flying, the tchniques, the inputs and what to expect!

Once again many thanks for your answers, they are extremely useful!!!!!

Baobab72

[Gordy]

Apply aft pressure to cyclic, climb, apply forward pressure to level off.

[[email protected]]

Baobab72 - for entry to climb or descent Power, Attitude, Trim - for level off from climb, Attitude, Power, Trim.

For academic helicopter flying there will be a nominal climbing speed which will be different from the cruise speed so the entry to the climb is initiated with power (raise collective to achieve desired climbing power) the speed is adjusted with cyclic to achieve the required climbing speed and then the aircraft is trimmed.

For the level off the attitude is adjusted to accelerate towards cruise speed at approximately 10% of the RoC below the desired level off height, then as height and speed get towards the desired datums, the power is adjusted to cruise power and then the aircraft is trimmed.

In practise, the aircraft can be climbed at any speed (if you have the power) so PAT still applies - raising the collective causes the nose to pitch up slightly and vice versa when lowering the lever (due to the difference in V squared between the advancing and retreating sides of the disc) so even a cruise speed climb or descent will need some attitude correction with cyclic.

As you have probably discovered, moving one control in a helicopter means compensating with the other two and you will find yourself using your feet much more to maintain balanced flight.

[Dennis Kenyon]

Just for the record: APT - Going UP .... Attitude - Power - Trim.
Levelling off .... ditto.
PAT - Going DOWN Power - Attitude - Trim.
Levelling off .... ditto

Nit-picking .... DRK

[[email protected]]

I'm sure you are right Dennis - it's been a long time since I taught basic climbing and descending:ok:

[baobab72]

Thanks to all of you
For the inputs, that APT attitude - pitch for the desired speed, 60kias -, power - 23"hg map in the r22 - and trim i guess it refers to adjusting the throttle to fine tune the rpm's -, and PAT for the descent, it is a very good and easy to remeber hint!
What if i want to perform a 500fpm climb for instance, do i control the roc by means of the collective and then use the throttle to set the power?

Many thanks

Baobab72

[Gordy]

I am all about KISS...... you are on lesson one, try not to over think...

Apply aft pressure to cyclic till speed comes back to about 60, climb, apply forward pressure to level off, adjust pressure to maintain straight and level.

This is the easiest way with minimal inputs and does not require any power changes or pedal input----which at your stage will create instability.

[Ascend Charlie]

Trim in a fixed wing means "get the skid ball in the middle, use elevator and aileron trim to remove all control forces."

In a helicopter, Trim means "Get the f*****g thing in balance, dopey!" because any power or speed change will affect the balance (skid ball), and then fine-tune the power settings and attitude for the airspeed.

"Pitch" has 2 meanings in choppers - one is for the nose up/down attitude, and the other is for the collective pitch setting. Try to use "power" for the collective and "attitude" for cyclic, because the equation is said as "Power + Attitude (in Balance) = Performance" , not "Collective plus Cyclic (with pedals) = Performance."

[[email protected]]

Baobab - you don't need to use the throttle - that is what the governor is there for. If you don't have a governor then your learning curve will be steeper because you will need to adjust the throttle every time you move the collective in order to keep the RRPM in the green.

You must get used to monitoring the MAP so you don't exceed the limits (easy to do) every time you raise the lever.

For a 500'pm climb - if you are at climbing speed already then raise the lever until the VSI reads 500'pm - if you are at cruise speed, bring the cyclic aft and raise the lever until you stabilise at climbing speed and 500'pm - in both cases the TRIM is fine tuning the attitude, fine tuning the collective position and, as already mentioned, putting the ball in the middle.

Gordy - we all know you can fly a helo around the sky just on cyclic with cruise power selected but Baobab wants to learn the correct and academic method - no point in learning bad habits now.

[Aucky]

What if i want to perform a 500fpm climb for instance, do i control the roc by means of the collective and then use the throttle to set the power?

In flight, R22/R44 - you don't need to twist the throttle if you have a governor, it's on, and all is working normally and being flown within limits. If, as you say, you want to climb at 500fpm you will need to bring the speed back to 60kts (Attitude to climb speed), select a MAP (power) RAISING THE COLLECTIVE LEVER (NOT TWISTING THE THROTTLE) to a MAP above that required for level flight, and not exceeding your max MAP available (found each flight on the chart above your head, using pressure altitude and temp), and adjust the trim to keep it in balance.

As the collective is raised the butterfly valve in the carburettor will open automatically by means of a mechanical linkage to the collective, this linkage is relatively well calibrated to compensate for the increase in drag through the rotor system for most in flight power settings, but it's not perfect. Additionally, the governor can sense changes in engine RPM electronically (a feed from the right magneto I believe), and will make small corrections to the throttle if required (felt through the twist grip as small movements), to maintain ERPM at the top of the green, and therefore RRPM in powered flight. So throttle correlation does most of the work, and the governor makes additional subtle adjustments. The only time we need to use the throttle manually is for the start, shut-down, and inflight following a governor malfunction (or potentially in limited power scenarios, but thats a topic for another day).

In most cases, R22, 2 on board, at sea level - level flight will require somewhere in the region of 18-19" MAP at 60kts, MAX allowable (5 min) climb power will be approx 24.5"/23.5" MAP (BETA/BETA II), so any power setting between the two will give some rate of climb, the more power the greater ROC. For 500fpm, adjust attitude for 60kts, set a notional power of around 23"MAP establish a climb, left pedal for balance, wait for the VSI to catch up (not likely to be an IVSI in a 22), and once ROC is established adjust MAP as required not exceeding the MAX allowable MAP. Simples.