Emergency turn

On Sat, 28 Mar 2009 12:27:36 -0500, Tired Bob wrote in :

Think ahead of where the plane is.

Contrary to post-crash stories, trees and walls don't jump out at aircraft. They are where they are all through the flight. Think about them BEFORE taking off and make your plans accordingly.

Factor in the wind, too. It really makes a huge difference in how much time you have to avoid the trees.

A split-S would be a half-roll to inverted, then hard up elevator to perform a half-loop to upright. An Immelman is hard up elevator, a half loop, then a half-roll to upright.

Split-S: goes down, reverses direction.

Immelman: goes up, reverses direction.

It sounds as though you just need more practice.

A lot depends on your plane, too. If you have a lot of dihedral in it, the rolling maneuvers may be pretty sloppy.

Marty

Are you teaching yourself to fly? That's an excellent way to learn how to repair and build airplanes (I taught myself to fly, on planes that I designed, and learned (a) how to repair airplanes, (b) how to design airplanes that can be post-holed into moist sod and survive*, and (c), eventually, how to fly planes).

As Martin said, plan your flight before the aircraft leaves the ground (or your hand). This is particularly important if you are a beginner, or rusty, or if the airplane, field, or day presents some unusual challenges. If you have a plan, then planned flight won't come as a surprise -- you'll only have to think fast for things you _didn't_ plan on.

If you can, plan on the most likely things that _might_ happen: "if I get within 50 feet of that tree, I need to veer off to the left", or "if my motor stops right _here_ I need to not take off, if it stops _there_ I need to grit my teeth and land straight ahead, if it stops _up there_ I'll have enough altitude and airspeed to turn", etc.

One of the most fascinating experiences I had was getting the opportunity to fly in a small twin-turboprop, and listen to the pilot's chatter on the intercom. Do you know that pause when your plane is lined up on the runway, but you're not accelerating yet? One of the things that is happening is that the pilots are agreeing on landmarks for one-engine-out events -- this is where we cut back the other one and hit the brakes, this is where we try to take off anyway, etc. That way if the s**t hits the fan, their response is coordinated and immediate. It doesn't hurt if both sides of your brain have a similar conversation before you launch your model.

As far as your question: It sounds like you are not rolling all the way vertical before you apply elevator, so you gain some altitude. You're also slowing down considerably, so you're lucky you're flying an egregiously overpowered airplane. As Martin said, dihedral makes this maneuver harder to do -- in general you need to add some rudder to make it all come out right, or just accept that the turn is going to be ugly.

Good luck, keep trying, and remember that the most important things that a pilot can have are altitude, airspeed and ideas -- if you have any two of the three you can spend some of of the two you have to get some of the one you don't, but if you're down to one you're in a world of hurt.

• Build everything in front of the wings out of strong materials: sheet backed with ply, basically. Then build everything behind the wings with stick-and-tissue construction, with triangular bracing. The front will absorb the impact, the back won't contribute.

This doesn't help if you post-hole into the ground in August, or if you fly straight into a tombstone (I learned how to fly in the spring, in a field across the road from a cemetery. The August post-hole came about after I picked up the hobby again).

Rudder. Nowadays, it seems nobody uses any rudder control or so I have heard some of the "old-timers" lament.. Fastest, sharpest turn I know how to make involves using the rudder along with the ailerons while turning. Takes practice just as anything else does but well worth the effort. A certain amount of elevator and throttle is also needed, esp. to recover from the tendency to stall. Learning to apply rudder input will also come in very handy during crosswind takeoffs and landings. Now, I am no "Rudder Maven" by any means but I do make it a point to practice with the rudder at some point in every flying session whether during crosswind flybys or just cranking a U turn at either end of the field just for fun. Prior to hearing those comments from the "old-timers", I only used the rudder for steering my plane around during taxiing, so I figured they had merit and I made it my goal to learn proper use of the rudder. Anyway, that's my advice for a sharp 180 turn.

I strongly suspect Marty hit the nail on the head with his observation that you need to think ahead of the plane.

Let me share some 'tricks' I use to help folks when teaching them how to fly. They may help you get 'ahead' of the plane sooner next time.

Flying at any field is possible if you internalize the general rules of aircraft placement and look to see how they impact with your specific field. The field I used to teach at was surrounded by trees and powerlines so the 'where is the plane' was needed from the first flights to solo.

The first step is to stand on the centerline of your runway with your shoulders parallel to the line of flight as the aircraft is taking off. Then you put your arms up with your hand open, fingers together and oriented so your thumb points up. Turn your head to look across the edge of your hand without moving your body and see what on the horizon you are pointing at. Note the strain on your neck. Do this for both left and right sides. The point you have identified is what you will use to demark the 'pilot line' for yourself (and the club if you are at a club field),.

Next is to step to the pilot station. If none is identified, try to step back about 25 feet and stand with your shoulders parallel to the line of flight again. This time when you put your hand up and view it in the same manner (including the neck strain) as before you will not see the previously identified point. Move your arm until your hand points at the original point and turn your head with it (I tell students to put their nose. Note how it feels in your neck.

What you have just identified are points of view that you want your aircraft on the other side of to prevent hitting yourself or other pilots.

The next thing to do is to identify turn points. I learned that telling students to look for a point on the horizon always ended with them loosing the aircraft since it did strange things as they were looking away from it. So I came up with a better way to do the job that should enable you to fly almost anywhere.

Stand at the pilots station and make sure your shoulders are parallel to the flight path. Look straight out. This is the 90 degree mark. Now put your arm up and look at the point you previously identified and we will call this the 0 mark. Make sure to turn your head with your arm as you move it to about 45 degrees which will be 1/2 way from 0 to 90. In other words follow your arm/hand with your nose. On both sides of the flight path we have just identified turn points. One will be the turn from crosswind to downwind leg and the other downwind to base leg.

The next thing is to figure out is when to turn from take off let to crosswind which is really easy to describe. Start the description with your arm up level and your open hand, fingers together and palm down. As you look across the back of your hand imagine the top of the airplane being level. Now raise your fingertips just enough that you can see the entire back of your hand. This is about the best climb angle for a beginner. The time to turn crosswind is when, in the above described attitude, you can see daylight between the horizon and your airplane. This automatically takes into account tree lines.

The last thing to figure out is the turn from base to final. Clearly you must turn shortly before you reach the point on the horizon we identified earlier as being on the extended centerline. How much depends on wind velocity, direction, and your aircraft speed and handling.

I use these for the first flight at every new field I fly and they work.

Good luck.

Jim Branaum AMA 1428

I would suggest that the most important thing to learn is how to make the airplane go where you want -- not where it wants. The best way of learning this is to use a computer flight program (I suggest Real Flight).

A split S is risky but in an emergency...... I fly at an airport sometimes and we must have spotters for full scale. No one noticed the 2 army helis coming in at low altitude. The shout went out " everyone land". I was flying a tower trainer and I did a split S, it dove right into the ground. I blame flimsy pushrods. I'll not use those kind again. Make sure the elevator is a PULL for UP.

mk They landed on the active runway, got out and took a leak and left.

Hmm, sounds like I need some work on the basics of thinking about flying to prevent these crises. I've been taking off and noodling around hoping to stay out of trouble -- in vain. Thanks for the replies -- I'll be changing that risky habit.

In a light plane, one type of "emergency" turn is named (and aptly) "Box Canyon Turn" It's a steep, sort of climbing turn away from an obstacle while holding the A/C on the edge of a stall. If done properly, the A/C all but stops travel towards the obstacle, and turns in about the smallest area possible. If not done properly, the ensuing stall and fall out can be not so good!

"Minimum radius turn" for the box canyon. In a 172, slow to

80 mph, apply 20 degrees flap, bank 60 degrees, full power and pull hard. No altitude change. The stall speed (normally about 55) is 1.41 times higher in a 60-degree bank so the 20 degrees of flap lowers the stall to well below 80. All of this should take no more than about ten seconds. A 172's flaps 20 stall is 49. In the 60-degree bank it's 69. A "climbing-away" turn is a chandelle and is much more difficult to do. You need more airspeed to start with because you're increasing the load factor just by pulling up, thereby raising the stall, so the airplane needs to dive first, using up precious room. It's used in very narrow places where the minimum radius turn won't do. I won't fly into anything that narrow without being able to see that there's lots of visibility and room on the other side. There are plenty of situations where you are doomed if you venture there.

Dan

That's why I used the word "sort of". Slowing the plane down by bringing the nose up while you turn is to me the basic part. Other settings vary with aircraft capability. The "Barn Door" flaps on a 172 are an interesting subject in themselves. I was very disappointed when Cessna changed from manually operated to electric flaps. Applying what you know as a light plane pilot to flying an RC model can get involved. Lack of hands on feel and in/from plane visual references are major differences to overcome.