Slowing Down to Land
 

Question: What's the best way to slow down a plane without flaps or ailerons, prior to landing. I've tried to "Flare Up" but have not yet gained enough confidence to avoid the eventual, well, you know....

RE: Slowing Down to Land
 

I cut the throttle on my downwind leg then crab (side slip) or make some slow S-turns while on final to bleed off some airspeed if I think I am still going too fast. Although these still use the control surfaces you mentioned, it's just what I do.

RE: Slowing Down to Land
 

A great way to slow down for landing is simply to cut throttle on the down wind and hold altitude, by slowly increasing elevator trim, until the proper speed is achieved at that point stop feeding in trim and the model will maintain that airspeed hands off. If you make small throttle changes to reduce the rate of descent, and shallow turns, you will still maintain the same airspeed. You should definitely practice go around's at altitude as the nose will pitch up upon full throttle, and you will need to practice compensating and re-trimming. A good stable approach and proper trim settings will make all of your landings great.

RE: Slowing Down to Land
 

Regardless, just watch your airspeed so it doesn't get TO low!!! Do everything at a high altitude first and watch the aircraft react to your inputs and be prepared to add throttle right away and go around.

CGr.

RE: Slowing Down to Land
 

Drag is the only force that can slow an airplane down.
There is the drag due to friction and the drag due to lift.

There is nothing you can do about the first type, since your plane has no flaps to deploy and no ailerons to perform a slip.
However, you can increase the drag due to lift via elevator control.

More elevator up produces higher wing's AOA.
Higher AOA produces more lift at the same speed or the same lift at slower speed.
Slower speed is what you want.
Critical AOA is the limit to that trick.
Critical AOA is the maximum AOA that your wing can take before stalling and loosing substantial amount of lift.

Just feed elevator gradually while you reduce throttle.

Practice stalling the wings high enough.
Get familiar with the max AOA and minimum speed that are safe for a regular landing.
Below the critical AOA, your elevator is your brake.

In a step dive, height becomes speed; hence, descend slowly.

Your plane has elevator and rudder only; hence proper aligment is key in order to avoid dramatic maneuvers when your plane is slow and low.

Read this article:

http://masportaviator.com/2004/01/17...ng-techniques/

RE: Slowing Down to Land
 

Good Stuff - thanks

RE: Slowing Down to Land
 

All landings are different as well as all airplanes.....If you have a high wing trainer type airframe then you can cut throttle on the down wind leg and glide to landing.....try that with a bipe and you'll never make the runway.....
A basic techique is to slow down and descend on the downwind leg...then on the base leg maintain altitude to slow down from the loss of altitude....as you turn final make sure to drop the nose..set up a nice glideslope...use the elevator to maintain speed and your throttle to control altitude......the last of the airspeed will bleed off as you flair to touch down....
I did say that correct by the way, elevator to maintain speed and throttle for altitude....
But like I said all landings are different as well as all airplanes.....you may have to have a click or two of throttle all the way to the runway...depending on the plane and the winds.....
Practice stalls up high so you know how she feels at stall speed....and stay above stall speed on approach....then pratice pratice pratice

RE: Slowing Down to Land
 

You can slow with the throttle. (Yeah, I know everybody knows that.)

In fact what happens when you back off the throttle, the prop pulls less (YES i KNOW) and less. It can get to a point where it acts as a brake. That's the point.

How long it works as a brake depends on the idle rpm that prop and engine can give. No matter how fast or slow, you can find a good throttle setting by test. Chop the throttle somewhere on your downwind or base leg. Chop it to idle and then give it a couple of clicks back. See what happens as you turn onto final and descend toward the threshold.

You want to come over the threashold at a nice safe, slow speed. Too fast? Start earlier next time. Too slow? Start later. But always have those couple of clicks as insurance that you're not flying too slowly.

Simple? If it works for you. Keep in mind that nowhere on the final do you want to see much of the underside of the plane. No matter how many clicks, you can kill the airplane with too much elevator. You got a good way to nail a safe airspeed so don't screw it up by bad elevator control.

Finding and using the place to "set the throttle" takes some of the workload off your flying a safe approach. Learning how much is too much underside to see turns your landings into the safest maneuver you know how to do.

RE: Slowing Down to Land
 

This is invaluable information for those of us learning (or trying to learn how) to land! Thanks for posting that.

RE: Slowing Down to Land
 

Try trimming the airplane for slow flight - pull the throttle back to something less than half (plane dependent) and reset the elevator trim to maintain level flight. Gently and slowly fly around the pattern a few times. Learn that in this configuration, you can move the throttle back a bump or two and the plane will descend. A few bumps forward and the plane gently climbs.


Kurt

RE: Slowing Down to Land
 

A good low idle rpm and a low pitch prop work well to slow a plane down. I shoot for somewhere around 2000/2400rpm. but Idont sacrifice a reliable idle rpm.

RE: Slowing Down to Land
 

Landings are controlled with the throttle and elevator as most are stating but if you haven't got the feel for the flare you should go practice a bit longer. Elevator control is a must. Some other little things that may help are the props you use. I use long props with light pitch and the prop acts like a breaking action. Once in a while I use a three bladed prop with some plane/engine combos and the breaking action of a three blade prop will slow a plane down. As LN stated, it's the drag that slows and some props just seem to add to that. A new pilot may over control the elevator and induce a stall if you slow too fast. Just start shooting some approaches or false landings a couple of mistakes high so you can get a feel for the landings. After you get it down do a lot of touch and goes during your day. It all comes to you with time and practice.;)

RE: Slowing Down to Land
 

If you really want to get good at landing, kill the engine and learn how to do dead stick landings. When you can place more than half of the landings just a few steps from you, you will have landings down.

RE: Slowing Down to Land
 

An important part of basic trimming of your airplane includes establishing a nice glide slope that is primarily used during landing. Let's say that you are on your downwind leg, straight and level at your cruise speed, you then drop the throttle to a couple of clicks above idle - the resulting descent angle is your glide slope. If it's too steep and fast you'll need to adjust it using up elevator to hold a nice slope and reduce speed. If it's too shallow and your controls are "wallowy" you'll need to adjust it using down elevator to increase the angle of descent to regain speed and control.

RE: Slowing Down to Land
 

Another hindrance to a good flair and slower landing speed is a nose heavy air plane. Just a few hours ago I helped a new comer to our club balance his Avistar. He had been flying it with the Cg towards the front of the plane because that was how his first instructor set it up for him. Absolutely the right thing to do for a true beginner;). But he has a little experience under his belt now, so we moved his battery aft and hence moved his Cg moved aft about 1/2" . Reccomended postion is 3 1/4" from LE and now his CG is about 3 3/8" from LE. He was impressed with how much easier his plane was to fly and land now.:D

A nose heavy plane tracks straigher and is more stable, so it is best to err towards nose heavy if you are a begginner or you are new to that particular plane. But a nose heavy plane lands at a faster speed and looses elevator authority as you near stall speed and try to flair. Many times this will also contribute to bouncing down the runway during landings.:eek: Make sure your CG is within reccomended range for that plane, but it will land slower and flair easier if the CG is slightly into the aft portion of the reccomended range.;)

RE: Slowing Down to Land
 

A HUGE ditto to this.

If the plane is nose heavy, everything else you try to do will only help a little, but you'll never solve the problem until you balance it properly

RE: Slowing Down to Land
 

It works both ways.......a tail-heavy plane is even worse when you are trying to maintain elevator authority. When doing weight and balance calculations when I was taking my pilot's training in full-scale, there was only a slim margin that you wanted to stay in and slightly nose-heavy was much better than tail heavy.

RE: Slowing Down to Land
 

This is true, but in 90% of the cases I have seen where a model lands hot, it is because they have the CG too far forward (Nose-heavy)

So they are not even close to that "slim margin"

RE: Slowing Down to Land
 

Only problem with applying that is you're talking about nose heavy versus too tail heavy. Trust the experienced flyers, our models are very seldom too tail heavy. What they almost always are when they're overly sensitive for an inexperienced flyer, is a little tail heavy and way too much elevator throw for the CG.

You can fly our models with the CG all the way to the back of the CG range, and as long as you tune the elevator throw to match the CG, you'll have a safe, controllable model. I can count on one hand the number of modelers who didn't look baffled when that was described to them. What you often get is some mumble about needing all that throw if they get into trouble. Another fantasy that is alive and well in our hobby.

What you get when you move the CG forward can often work, but most modelers don't tune the throw for that either. Tune the throw or not, what you will get 100% of the time is a less efficient model. Moving back will give a model that actually stalls at a slower speed thanks to lower wing loading and higher efficiency (less drag). But you've got to either adjust the throws to keep your safe, secure feel, or learn to fly like every one of our 3D flyers fly. They do it all the time and do it safely.

RE: Slowing Down to Land
 

BTW, a tail heavy model HAS elevator authority. You don't have to work to maintain it. You got it. You usually need to use less of it than more.

As you move the CG back you get better and better elevator response. And your airplane gets more and more efficient as you lose the induced wing loading. Less loading, less drag, less elevator needed.

RE: Slowing Down to Land
 

All Good Stuff!

I practiced slowing down last night with the elevator and realized I've been doing this (albeit unconsciously) for some time.  It was good to know what I was doing and to see the results though.  This evening, I moved the CG back 3/16" - I could go back up to 1/4". 

If the weather corporates tomorrow, and it's not to dark when I get home, I take the Cub up again before dinner.

RE: Slowing Down to Land
 

One thing to try before you ever go past the recomended CG range is throttle to idle (at a safe altitude) slowly feed in elevator until you either stall or you reach the max elevator throw. If you reach full throw and it just starts to descend then you have one of two problems or both. 1. not enough elevator authority, generally due to too little throw or too large a gap, or 2. Your too nose heavy. Both of these are easy to adjust or fix. If however you reach a stall before you reach full throw then you have more throw then needed. If it is close leave it, if it is excessive then it needs to be reduced. Remember you need less elevator as speed increases. The problem with moving the CG back is as you get closer to the critical AoA the center of lift (CoL) moves forwards and if the CoL reaches or passes the CoG then you reach a negative stability state and that can be fatal. It may fly a little better each time you move it back, but you will reach a point that stability will suddenly be lost with little warning. Often it is too late once you get to that point.

RE: Slowing Down to Land
 

You're probsbly diving at the runway. It's a common reaction with new flyers who aren't comfortable with being near the ground. I try to be less than 3 feet off the ground and level when I get to the end of the runway when it's windy, and as low as a foot when it's not. The more wind there is, the more dive you can get away with.

RE: Slowing Down to Land
 

Or, you may be flying a high wing trainer with significant dihedral, dihedral that self-rights itself rather than stalling off to the left or right.

Just sayin' ...

RE: Slowing Down to Land
 

No it will still stall, just straight forward.