Learning to Fly RC Planes – Lesson 5: Getting Down to Business
a guest post by Tony Murano for RC-helicopters.net
Prerequisites: You have good control of the plane in the air in level flight. You very rarely get disoriented and can figure out how to reorient yourself when it goes wrong. You’ve looped your plane, or at least tried to, and you understand how to convert altitude into airspeed and have played around with this a little. Your landings work out okay most of the time, and you can normally land within 30m (or 30 yards) of yourself provided you aren’t landing due to dead batteries. You have probably done 10-20 flights.
Objectives: Low-level low speed passes, a new trick or two, and learning to fly in a 3D space.
Congratulations – if you mostly pass the prerequisite list at the top then you are well on your way to learning how to fly RC.
Just going to refresh a few old things before we get started:
large scale airplane models
plastic scale models
p 51 h
- Thinking ahead – concentrate not only on where the plane is and what it is doing but where it will be in a few seconds time – this is going to be critical as we bring down your altitude.
- Don’t be afraid of altitude – it is still your friend. If you get in trouble your are generally better of being higher.
- Wind is still something you should avoid, although you can now comfortably fly in fast walk/slow run wind (0-8km/hr, 0-5mph – use your TX ribbon to check the airspeed).
- Remember, if you are doing low altitude work, do it while you have a fresh battery. Losing power close to the ground is no fun.
Depending on how you think your flying is going it may well be time to adjust your controls one step on your control horn (so move the control surface linkage one hole closer to the control surface). If you do this make sure you put in two flights to re-familiarise yourself with the plane before moving onto the other things in this part of the course.
Thinking differently about altitude
So over the previous “lessons”, I’ve stressed the importance of good altitude. Now that you have good confidence in the air we are going to start bringing the altitude down. Rather than flying at 30 meters, we are going to come down to about 20 meters, which is about 2 mistakes high. This is the cruising height – we will come lower than this while maneuvering.
It is time to start coming down to less than 10 meters altitude more regularly, but you are not ready to just fly at this height all the time. Instead, all of our incursions into the last 10 meters above the ground will be planned maneuvers which we come down, execute and climb out.
The nature of your flying is going to change a bit now – climb to altitude (investing in potential energy) and then use that energy for some maneuvers, then go reestablish your altitude etc.
It is also going to change how you approach obstacles – with enough energy you might decide to climb over obstacles rather than flying around them, and with your altitude coming down you are going to start being low enough that such things might be around.
A note about wing folding
Many trainers have quite light wings which may start to fold if you give them too much speed and try to pull up to sharply. The Electrafun, in particular, can fold wings under extreme maneuvers and high speed. If you have prepped the wing as per these notes that will help, but this is just something you need to be conscious of. For example, if you put two stall turns together you will push the EF wing to its limits, if you put three stall turns together you will almost certainly fold its wing.
Two things fold wings – too much airspeed and trying to change kinetic energy (ie speed) into potential energy (ie altitude) too quickly. Of these two, the latter is the worst. In other words, if you have a lot of speed pull up gently whilst you turn airspeed into altitude. Pulling up hard is more likely to fold the wing. Obviously, if the ground is just there, pull up as hard as you have to and hope for the best.
Low-Speed Low-Level Passes
With you standing in the middle of your field, as your plane flies over your head on the downwind leg at 15-20 meters altitude bring the throttle to about the 50% position and let it gradually lose altitude to around 10 meters as it is about 40-50 meters away from you. Do a medium 180-degree turn, making sure to use some elevator to make the turn a bit faster, and to prevent the plane from losing too much altitude. If there is any significant wind your plane should now be pointed directly into it.
After the corner use the elevator to slowly bring the plane down to around 3 meters altitude (1.5 people high). Use your own judgment as to whether you need less or more throttle to maintain this altitude and dial in the right throttle.
Let the plane pass you at about 3 meters altitude and run it out the other direction for another two seconds or so (provided there is plenty of space). Go 100% throttle and climb out to 15-20 meters, back to 50%, turn towards yourself, and get ready to set it all up again. (note – you may not be able to reach 15-20 meters before you turn back – just do your best).
On the next run use your own judgment about the height you need to start your turn at, what throttle position to use etc.
If anything goes wrong on this you need to open the throttle, get the wings level if they are not already, and pull up for altitude.
This series of exercises will really teach you some control finesse. It is putting you in a tight spot, the turns into the wind can go wrong as you are reasonably close to the ground to make a turn, and the possibility of a mistake close to the ground on the actual pass is always there as well.
As you get confident with this try reducing the altitude for the low-speed pass from 3 meters, to 2 meters (about your head height) to 1 meter eventually (about your waist height) – take your time getting there!
You thought you could fly didn’t you 😎 Keep at it – these exercises are some of the most demanding and beneficial you will do. They really teach you the minimum needed to keep a plane flying, and how to have precise, spot on control.
Some new tricks
All the way back in part two we talked about stall turns. It’s a bit debatable whether this is a trick, but it does make the aircraft do something cool, and is a neat way to quickly get airspeed, turn 180 degrees and set up for a high energy trick.
At about 15-20 meters minimum altitude feed in full left or full right rudder and hold it. Don’t use the elevator at all. The plane will bank until its wings come past perpendicular. As the wings come past perpendicular and the plane starts to flip over release the rudder. The plane will stall, and fall out of the sky, turning approximately 180 degrees in the process. Use a little up elevator to restore level flight.
One neat combination is to put together a stall turn with a series of loops. At full throttle at 25 meters minimum cause a stall turn, and then use a full up elevator to make the plane loop. Provided the plane pulls the first loop cleanly, just hold the elevator and pull the second loop straight away. If you find you don’t have quite enough energy for the second loop then immediately after the stall turn let the plane fall for just an instant longer for a little more energy. By gradually letting the plane dive for just an instant longer you might just get three loops in a row. Also by elongating the dive at the end of each loop, you can trade a little altitude for more energy to pull another loop. Do be careful about the stress on your wings and your overall altitude though.
Another couple of easy tricks are a crucifix stall and the similar and slightly more advanced hammerhead stall.
With full throttle and plenty of energy (either from a dive or a stall turn) simply pull back on the elevator until the plane is perpendicular to the ground (so from in front or behind its wings make it look at little like a crucifix). Use finesse on the elevator to hold the plane perpendicular for as long as possible (it may need a little down, or a little up elevator to hold it in position). Eventually, the aircraft will stall, possibly coming over on its back, in which case pull up once you have a little airspeed, or fall forwards, in which case just use a little up elevator to restore level flight once you have enough airspeed.
The hammerhead stall is a variation on the crucifix stall. As you approach the stall point while climbing perpendicular feed in full left or full right rudder. The aim is to make the plane fall to the side rather than forwards or onto its back – from behind or in front the wing tip looks a little like the head of a hammer being swung. This maneuver will be quite hard to get textbook with a high dihedral trainer, but you should get something approximately correct.
If you get this correct you should emerge flying in exactly the opposite direction of what you entered the hammerhead stall in.
Finally, let’s talk about a snap roll which is one of the few ways to make your three channel trainer role. Leave this one until you have tried all the others on a few other flights. Once you are getting a feel for how much space you need to recover, turn etc give this a go.
From not less than 25 meters altitude, and with full throttle and a fresh battery, dive for 5 meters building up plenty of airspeeds. Pull up with the elevator until the nose is about 20 degrees above horizontal, release the elevator and give full rudder input and hold it(either direction) while the plane rolls through 360 degrees until the level flight is restored. If you’ve gotten the timing right the plane will snap roll, probably losing 2 or 3 meters of altitude in the process. If you don’t have enough energy or your timing is slightly off you may end up with a stall turn, or possibly halfway through the roll upside down. In either case, let go of the rudder, and use gentle up the elevator to restore level flight. Provided you started your snap roll at 20 meters you will have plenty of room to recover, even if things do go wrong.
More flying stuff
Okay, well now you have some tricks to work on. At the same time start using your altitude for some more interesting flying, like diving from 30 meters down to 20 meters and just doing some tight corners, and noticing (and enjoying) the difference in how the plane handles with the extra speed.
One thing to be a little careful of as you do this is you will find that the plane is more responsive with more airspeed. Just be aware of those stall turns. If you do one too close to the ground you will have a crash, so use finesse on the stick. You will also find that you can sustain a higher banked turn with more airspeed (that is, you stall turn later), but exercise care when your altitude is down.
Your next plane
You are already thinking about it, aren’t you? Maybe, maybe not. Either way, put it to the back of your mind for the moment while we try and get every bit of fun and learning we can out of the trainer. I’ll talk about your next plane in the next part of the “course”. For the moment I would suggest you hold off.
That’s it for this part
So, that’s it for this part – there is a lot of stuff for you to learn here and a lot of stuff to practice. Probably 20 flights worth give or take. So hopefully I will see you for Part 8 by which stage you will have a pretty good handle on what your trainer can and can’t do.
You will probably find after some practice you are varying the starting altitudes for maneuvers quite a bit based on your own sense of what is required etc. Go for it! Just don’t get too far ahead of yourself. The difference between a close call and a really serious crash is just 5 meters difference in starting altitude.
Don’t be afraid to try out some crazy stuff yourself once you have all this under control. Just remember when you are trying something new:
- Get plenty of altitude
- Keep on thinking in front of the plane, particularly about your altitude.
Keep on practicing your landings. By the time you come back for part 8, your planned landings should be within 15 meters of yourself almost everytime, and unplanned landings due to power loss at a starting altitude of anything over 2 meters should be a non-event.