ahicks

My Feedback: (2)

On the bold, wow, I don't hear many others using that term often! It's how I would describe what many are talking about when they mention flying the plane in nose high, controlling altitude with throttle? Full scale student training involves MANY exercises in what they call "minimum controllable airspeed". This consisting of flying the plane up to a very safe altitude, then raising the nose up to some ridiculous angle while slowing the plane, then seeing just how slow you can get it while maintaining that altitude (using up to/including full power)? The plane is said to be flying "in back of the curve" at this point. Of note is that mistakes here end in "unusual attitude recovery" lessons (what a blast!), but I think the point of the minimum controllable airspeed is an exercise that can eventually be used to land or take off using the minimum amount of runway?

Also, that forward slip often appearing like knife edge flight, couldn't agree more. Presenting the side of the plane to it's forward motion, that's how you slow a plane quickly, or prevent/minimize acceleration while dropping nearly straight down! That's also a plane you had better know well prior to that. Being all cross controlled like that is an invitation for a mistake or a stall - with little or no chance for recovery as you're generally going to be doing that on final?

Last, IMHO, if there's any surprises for the uninitiated while flying tail heavy (or maybe a little too tail heavy?), it's that if taken too far, the plane is no longer capable of regaining airspeed if left on it's own? Most like to fly slightly nose heavy (to varying degrees), and I think this is why. A neutral (or slightly tail heavy) plane requires the pilot be cognizant of airspeed at all times - for he is now fully responsible for maintaining it! The plane will no longer build airspeed if left to it's own devices. The nose heavy plane will stall, dropping it's nose in the process, building airspeed all by itself (assuming only that there is enough airspace to allow that). Tail heavy, if the plane is slowing or getting mushy, YOU need to drop it's nose or add power to correct, or be prepared for the consequences (a plane with little or no forward airspeed)? -Al

acerc

Exactly the point of the recommended range is just a starting point. Only through flight can one find the true balance.

Airplanes400

My Feedback: (349)

I too, built a tribute plane for my mother-in-law several years back, who is now my ex-mother-in-law!
Here is the tribute plane.



Then, I put this in my backyard ...

Instructor

My Feedback: (16)

I have been flying model airplanes for 53 years. I have noticed lately that a lot of guys have an aft CG. When they try to land, their plane will balloon a lot. Then they add expo to try to correct this condition. I also have heard them say "It is real pitch sensitive in flight, so I add expo to get rid of the sensitive pitch". Having the correct CG, will solve a lot of these problems. It might take a few flights to get the CG correct, but when you get it right, you'll find that you don't need EXPO at all. Then there is the "It takes a lot of elevator to flair on landing" which tells me that they have a "Nose heavy CG". They will use High rate to take off and land, but switch to low rate during flight. To many things to concentrate on during flight. If you forget to switch any switches, then you have a problem trying to land. I can see the 3-D guys setting up their plane on a mode switch and then switching for what mode they want during flight. It's almost impossible to land a 3-D plane with a 45º deflection on the elevator or ailerons. Just my 2 cents worth. Have fun and enjoy.......

Larry / Instructor

dalolyn

My Feedback: (7)

How many of you have flown a airplane in a strong headwind and landed the plane with no forward movement. My 96" cub will do this fairly well, sometimes
I swear it will go backwards for a bit in a real strong headwind.

Andy_S

I was taught to use the throttle to control rate of descent, like said earlier, and use the elevator for airspeed in exchange for altitude.
Consistently managing touchdown speed starts with the base leg. If a landing is bad, I usually ask about how precisely the base leg was executed, or if it was just an after thought of a 180 degree bank turn onto final. All things being equal, any given approach can be modified just by the altitude, location and speed of the base leg. Fly it perpendicular to the runway, making crisp 90 degree turns in and out of it.
It can be boring at first to fly with such a large margin for error, but then, I prefer boring landings to exciting ones if you know what I mean.

sensei

Obviously you may have never properly setup or even flown a 3D airplane because when they are set up properly the C/G is not too far forward, or aft, and you can easily take off, fly and land without ever switching from full 3D rates back to mid or low rates, I do it all the time and it is really no problem for a seasoned pilot with a properly setup airplane. Just saying.

Bob

Instructor

My Feedback: (16)

Are you still flying this plane? If so, you need the cut the elevator throw. About eight years back, a guy came to our field and wanted to join our club. He had a Top Flite AT-6. He said he had a few guys trying to help him with this plane, but it just snapped on take off. It is hard to tell just how much throw there is on a rather large elevator from just looking at it. I tried to take it off for him and it wanted to snap on take off. I managed to get it down without any damage. I asked him if the throw was correct and he told me it was. I cut the throw down to half of what he had and it flew fine. After checking the throw setting he had, I found it to be 7/8" insted of 5/8" like the book said. Then I found the CG aft by 1/4". Scale models won't take an aft CG like sport models do. They also don't like more throw than is recomemded for the High rate settings.....

Larry / Instructor

Instructor

My Feedback: (16)

Hi Bob,

To tell you the truth, I have never flown a 3-D airplane. I have a few friends here in North East PA that set them up that way and that's what they tell me. If you have found the "sweet spot" and like the way your planes fly, then by all means contuniue setting them up that way. We all know, not everyone flies the same.....

Larry / Instructor

sensei

Hello Larry,

If you haven't tried it, maybe you should because it is real a rush. After just over 35 years of flying control line, free flight, sport, pattern, speed, and scale RC flying I was board out of my mind, until one day I gave 3D a shot... Well that was well over a decade ago now and still having a blast.

Bob

sensei

Around 28 or 29 years ago in the Antelope Valley California I had a Lanier Transit with a K&B .45 that I modified to have ailerons, anyway I remember one day while I was flying at the base of the Palmdale mountains the wind began to blow so hard at one point that with that .45 wide open my airplane was move slightly backwards pointed into the wind and there was nothing I could do about it but dump the nose slightly and milk it to the ground, the moment it touched down and I cut the throttle it immediately flipped on it's back.

Bob

speedracerntrixie

My Feedback: (29)

The airplane was raced just this once and the hung up in my mother in laws sewing room. As I stated, the CG issue was that the airfoil had a very forward center of lift and the cheek cowls are a couple inches out and go all the way back to the wing LE. It was initially set up with 1/4" elevator deflection each direction and expo set to 30%.

HighPlains

My Feedback: (1)

This is the classic power curve, sometimes referred to as the J-curve that shows several important concepts. Note that the aircraft drag is composed of two components, the form drag which results from changes in speed. It goes up roughly with the square of speed, in other words double the speed and you have 4 times as much drag.

The other drag is induced drag that comes from creating lift. The slower you go, the higher drag becomes from creating lift. When you combine both, you end up with a curve with a bottom. At that bottom, that is the speed that the airplane will fly in level in un-accelerated flight with the lowest possible power.

As ahicks stated, the left side of the curve is where you are flying when you are using throttle to control descent with throttle. If more elevator is applied to create more lift, it also creates more drag and thus more power is required.

However, you can also fly on the left side of the curve (the so-called "backside of the curve") when dead-stick with no engine power. Many people end up here when they crash a plane trying to get back to the field without even knowing what really happen to them. Often the radio is blamed, when in reality the airplane falls out of flight in a stall.





Now to avoid crashing when flying on the backside of the curve while deadstick, you have to release the elevator while you have some altitude and pick up speed once again so that you are able to flair. Otherwise, more elevator up to the final stall will just increase the rate of altitude loss. But this is a very powerful way to lose altitude and slow a model down to land in the minimum distance.

YellowBlueBird

Go back a few decades, before we had full controls. The planes were always landed dead stick. When the approach was too low to make a circle and to high to get down before hitting the barbed wire fence at the other end of the field just hit rudder left, right, left, right. It would slow down.
I have a pulse125 that tends to float and eat up all of the field, this old trick works just fine. I have never been able to get the pulse to slow in a side slip.

Jerry

sensei

I am a guy and as the saying goes, most guys are very visual so can any of you post video so we may see the slowing and landing techniques you use, it would be great for us to see.

Bob

BMatthews

Instructor, I too had misgivings with that much elevator and aileron on the first flat foamie 3D model I flew. But it turns out that these things fly so slowly that they are very controllable even on full rates and with 45 to 50 degrees of surface throw.

Same with the rearward CG location to where it's even slightly unstable. They might be unstable according to the math but in reality I never notice it in flight unless I'm trying to travel a fair ways in level for some odd reason. In those cases it needs the odd little nudge to correct a very mild divergence now and then. It's not at all like you end up chasing it around.

ahicks

My Feedback: (2)

Instructor,
To continue with Bob's line of thoughts regarding 3D, I couldn't agree more? Sounds like we have similar flying histories. Also, with power it's entirely possible to land a plane with the elevator at 45 degrees up, tail wheel (or rudder?) first. Roll out will be about 2 feet, depending on headwind! I'm another that uses expo to my advantage when flying a plane set up for 3D, mostly as I don't have to think about hi or low rates any more (less thinking is good!), and because some time has gone into expo setup requirements, I have the advantage of flying a plane with lock to lock throws on all control surfaces, while providing very civilized behavior around center stick....

Don't mean to beat anyone up, but making statements like the ones you made earlier about CG and expo? Those are the type that people hear often enough to start believing, especially when coming from an/their instructor. Those are precisely the thoughts they need to learn are NOT TRUE when/if they are going to continue beyond that second or third plane, towards more advanced flying. Making statements like those, without further qualifying them, are often doing that student more harm than good?

bpbrinson

Airplane manufacturer CG recommendations are always toward the forward range. It takes time to find the proper CG for the airplane AND your flying style. I have flown large scale birds, aerobatic, lots of pylon racers, deltas, and currently sport fly F5D and F5B hotliners. Every airplane has a different way to slow for landing and personality. You have to get it up to a safe height and play with them to the edge of control. Some are nasty and some are sweethearts. With the computer radios you can usually soften the nasty ones a bit and play with CG extremes. One story of getting behind the curve. I flew a friends Byron F-16 (sweetheart) and was at a DF fly-in in the 80's. They had a fast pass/slow pass contest. The Byron was a shoe in for the slow pass prize the way I had it set up. I entered the "speed" trap at about 10 feet altitude, full up and full throttle. I was losing altitude and had nowhere to go but down. Landing gear? Belly flop? My mind was racing. I started to release back pressure and I think a small gust on this calm day saved me the humiliation. Started getting a little altitude at about 3 feet above the deck. Speed was 11 mph on that pass!

TheRickster

My Feedback: (12)

Most peoples problems with building up speed on landing is because they will fly the whole flight at 50ft altitude then when it is time to set up for landing they climb to 200ft and try to do space shuttle approaches.. I always start losing altitude on the downwind leg then when I turn up wind I am at a comfortable 10ft or so aligned with the runway still under light power. Fly to the threshold and flare and presto it is down....

Rick

lopflyers

My Feedback: (12)

wow, never heard of that technique . I'll try it just x fun

Granpooba

My Feedback: (5)

Ditto ! Let me add that you are the first posting here that has even begun to mention a pattern, such as downwind !

Their is a pattern fellows and that is what I have flown all my real life and with models. All your attitude, trimming and speed control is begun to be set and applied upon entering your down wind leg. Then all you have to do afterwards is make very small power / speed adjustments. You should not have to be doing rolls, slips or any other aerobatic maneuver to control your landing speed.

Just me personal opinion !

bpbrinson

I agree! People are afraid to learn to fly slow. Yes, it gets mushy and insecure feeling…… Fly the plane!

Brooks

JPMacG

My Feedback: (2)

A downside to the trend towards using bigger and bigger engines is landing. One of my models will fly well above stall speed with the engine at idle. So either I have to literally fly the model onto the ground or kill the engine on final.

Hossfly

This forum is really a great forum. IMO the best lesson here is that if the pilot pays attention, he can/will get the machine to roll to a stop, all in one piece using a whole BUNCH of methods and skills. Really, is there any wrong in the use of the "whatever it takes" method?
I have no interest and darn well no skill in the 3D world, but I can do very well with landings. My most fun in RC is having a machine on the field and the day is either all alone or just a few pilots not doing much. All kinds of "landing" maneuvers can be played with, such as dead stick with engine out and some with it in idle. Hitting a spot on the facility using every thought of approach one can think of. I really like to spend time making crosswind approaches, landing, and then following the landing with a go-around take-off. Come in right on the deck about 2-4 feet off, pull up into an inside loop and then land on the "spot" or close to it. Doing all this the pilot will find himself using every one of the techniques displayed in this forum plus some additional ones. Try it, you will like it. I do.
For a good and quick slow down, fly an initial approach at some altitude between estimated 50 to 75 feet altitude. Over the runway end or maybe up to 200 feet down over the runway, roll into 45 degrees bank (later use 60 - 75 degrees) then roll out, throttle back, drop gear, then flaps (if they are there to use) and roll into a 45-60 degree bank descending toward the runway. Plan a roll-out about 100 feet from approach end, 10 to 20 ft. high, shooting to touch down at 20 to 40 ft (depending on your RW length). Let the machine slowly sink, wing down into the wind, and rudder the fuselage straight down the runway. As you enter the round-out and slowly ease back on the throttle, the elevator will lose effectiveness due to loss of prop wind-flow, thus requiring more elevator. Mind you these changes are"miniscule" but needed and smoothly. As soon as a wheel touches (BTW do NOT allow the wing to do the touch!! ) lower the nose, if a 3-wheeler to ground. If a tail drager gently hold enough UP to keep tail and Tail wheel down for steering. Once you have stopped the model, hold full aileron INTO the wind, and tail down. Nose wheel, use steering to keep it on the turf, usually a bit of nose down, on ground.
Taxi in and shut down.

Fuel up and do it again!

combatpigg

My Feedback: (3)

I do everything possible to eliminate dead, fun robbing weight and also fly with the most rearward CG that I'm comfortable with. This will make the plane seem lighter VS flying with a more forward CG. The more forward CGs raise the stall speed.