DLG/F3K - PlanaBH

[Lambreta]

Outro texto.

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If one doesn't take the time to set up DLGs well, then one doesn't know how a well set up DLG should fly! One also doesn't have the practice at doing it, so it becomes a hassle and takes a lot of time. And the results are uncertain. That is because plane setup is a skill just like any other. It becomes faster and more automatic with experience. You won't get that experience without doing the work!

In the vast majority of the cases where someone puts their transmitter into my hands, the plane is set up sufficiently poorly to hurt the pilot's performance.

The throws you want may not be the throws wanted by someone else. Take a plane setup by IMAC pilot Jim Cokonis (ShadowFalcon). Is his plane fairly well set up? Yes... If you only want to move the sticks about an eighth of an inch for normal maneuvers. He has the skill on the sticks to do that with precision. Do you? If not, then his well set up plane would be poorly set up for you. The less precision you have with the sticks, the more toned back you need the control response to be, so that you can maintain adequate precision in flight.

Let's look at rudder throws for example. It turns out that the efficient range for rudder throws is about 13mm or about half an inch. Beyond that, efficiency goes to garbage. Amazingly enough, that is pretty true regardless of the percentage chord of the rudder. That was a surprising result from one of my analysis threads. So one could set up such that rudder throw is only a half an inch. Or, one could set up an inch of throw, but except for real emergencies, only use the inner half of that throw range. Both options could be considered well set up; it depends somewhat on how the pilot will use it. If you like to play close tag with trees, then you likely need that inch available. Otherwise, you'd likely be better off without it. When it comes to using rudder, it is better to use a little too little than a little too much. Having reduced travel available helps prevent over-ruddering.

CG is another one of those things... Some pilots make a study of how their planes fly. They can keep the plane flying efficiently regardless of conditions and regardless of CG setting. Other pilots have no clue. They need the plane to be fairly pitch stable to make up for this. Also, "optimal" CG position is a function of turbulence level, as are optimal airspeeds (more turbulence -> fly very slightly faster for same camber setting). That's just a minor fact of life in the Reynolds numbers range in which we play. The neutral point is not a static point for us. The behavior of our wings is not a constant. So there isn't a single perfect CG setting either. Even the range of desirable CG positions may change a little as conditions change.

Some manufacturers provide good guidelines for things like throws and CG. Others provide essentially no guidance. But in any event it is a good idea for pilots to have enough confidence/skill at the sticks to be able to safely fly the plane regardless of settings. It is also a good idea for the pilot to have the skills in plane setup to then be able to fix it so it flies well.

Heck, one should be able to take a mystery plane and get it set up reasonably well fairly quickly. That would still be set up better than the vast majority of planes out there. Then, fine tuning takes more time and familiarity with the plane.

For instance, take mystery plane. Let's say the pilot is pretty good at the sticks, smooth, and doesn't over-control the plane. So, let's set fairly conventional starting throws of +/- 3/8" aileron, +/- 3/4" rudder, (assuming top mounted stab) as much down throw as one can get without hitting the boom, and some reasonable degree of up throw - lets start at half an inch to make up a number. Put the starting CG about 3" behind the leading edge of the wing. Set the elevator trim to be parallel with the boom. Now the plane should be flyable regardless of the model. Perhaps not easily, or hands-off, but flyable.

Set the camber in cruise. Lacking info to the contrary, that is where the upper surface of the wing near the root is fairly flat across the hingeline.

Give it a toss and trim elevator so that it will try to fly hands-off.

Now launch it and get a little altitude. Put the plane in a vertical dive and let it build up some speed. If it pulls up, then give it some down trim. If it tries to go inverted, then give it some up trim. Now we have a trim position that would be somewhere in the ballpark for pitch neutral provided the CG was set approximately at the neutral point. Yes, there is some handwaving and some caveats here but it should be close.

Now, add a few clicks of up trim (perhaps 3 but how much will depend on the servo you are using and on whether or not you set up the transmitter such that each trim click moves the servo - which you should have done). Then leave trim alone... Adjust CG in minute increments until the plane is flying at a desirable speed for cruise trim.

This method somewhat decouples the elevator trim question and the CG location question which is why I presented it as an alternative to the classic methods. It should get you in the ballpark pretty quickly which is the point of the exercise.

Now lets look at response rates in roll and pitch. If the plane is super responsive in pitch but dead in roll, then increase aileron travel and/or reduce elevator travel. Get the plane to where the pitch and roll response seem to be at the same rate as one moves the sticks. One can generally set this in the dual rates setup, even if dual rates are not turned on by a switch. That is, one can use the same rate for all flight modes/conditions. I advocate that - less to mess with and mess up as one flies. Our DLGs don't really have a wide enough speed range to need multiple rates. If you have to mess with the travel adjustments you might have to re-visit the elevator trim as the servo can end up moving a little depending on your luck.

Next, lets set up pitch-neutral roll. In level flight, roll back and forth quickly over shallow bank angles. Make sure you are using only aileron to do this, no elevator! If the spring tension is not high on the sticks, chances are you can't do this well enough. Now, if the plane gradually pitches down, increase the differential slightly - make the down aileron go down a bit more and the up aileron go up a bit less. If the plane pitches up some, then do the reverse. Note the plane will likely slow down some during this maneuver but that is NOT the same thing as a pitch response. Making the plane move costs energy and that is paid for by either altitude (potential energy) or speed (kinetic energy) or both. What you want to watch is the angle of the tailboom (or whole fuselage) relative to horizontal. You don't want that angle changing.

Is this where you really want your differential? If you are a beginner/intermediate pilot, then I'd say yes. If you are advanced/expert, well then it is your choice. You should have the skillz to deal with the pitch change induced by aileron input.

Now realize I'm not an advocate of aileron->rudder mix. It is wrong more than it is right IMHO, in terms of percentage of flight time. But let's assume you want it. So this is when you'd set it up.

Go back to the small quick rolls. Watch how the fuselage changes pointing direction, left and right. When the plane is rolling in the clockwise direction, then the fuselage will yaw to the left. And vice-versa. So add a little aileron->rudder mix and check the results. Dial that mix until the fuselage maintains a constant pointing direction during the shallow roll maneuvers.

BTW, will this give you an axial roll? NO! It will just start out close to axial so it is not bad for initiating rolls from level flight. The required rudder correction direction is reversed when the plane is flying inverted (reversed at the sticks that is)... As I said, automatic corrections are wrong more than they are right. You can't beat skill at the sticks. But, you're the pilot. You pick your poison and take your chances.

Now, add in a mix for elevator->camber that adds perhaps 2mm down flaperons for half stick up elevator. It's just a starting point anyway. What you should find is that now the plane is suddenly a lot livelier in thermal turns and climbs more easily.

Now go do the loop test and dial in the up elevator throw and the elevator->camber mix. http://www.rcgroups.com/forums/showthread.php?t=1234569

At this point, the plane should be flying pretty well in cruise mode/condition and should thermal fairly well. It should be smoothly responsive on the sticks.

Now go ahead and duplicate this setup to create speed+launch and float flight modes/conditions.

For speed, adjust the camber to be 2mm up from where it was for cruise. That's a good starting guess if one doesn't have the info for that wing.

For float, adjust the camber to be 2mm down from where it was for cruise. Again, just a good guess lacking data for the wing. If Edge, go 1.5mm for starting.

Fly the plane in each of these modes, and trim the elevator to adjust the speeds. Don't bother trying to trim float if the air is not smooth while you are doing this setup. It is too difficult.

Now set up a launch preset. This would just be a couple mm up elevator added to the speed mode. Adjust for a nice pitch response on the throw.

Perhaps one can invent a quick and dirty test for how much elevator to use. Put the plane in a near vertical dive in speed mode from perhaps a quarter above launch height. Hit the preset button as one has speed approaching the ground. Make adjustments to get a good compromise between speed retention and altitude loss from when the preset is hit. Or, even better, use an altimiter.

For float mode, which is a thermal mode (cruise being the other thermal mode) reduce the elevator->flap mix for up elevator and down flaps. Since the flaps start farther down, there is less margin for them to go lower. For a starting guess, cut the motion in half.

For speed mode, probably just go ahead and cut the elevator->flap mix in half, both directions.

Ok, now just go and fly the plane for a while in a variety of conditions. Fine tune as you see fit.

Gerald

PS - Forgot to mention about dialing in landing flaps, but I covered that anyway in the sticky thread. This post duplicates a lot of info from that thread anyway, but perhaps with a bit more of an at-the-field perspective and doing things slightly differently in a few cases. There isn't one single approach that works. But doing things in an appropriate order really makes the job a lot easier!"

[Marcelo]

Eu vou dar uma treinada. Peguei o Siriuis do Alexandre Cruz, e tenho um chopstick em bala tambem...assim que lpegar a manha pego um modelinho pro mesmo..

[marcelowolf]

Olá pessoal.....gostaria de saber onde o pessoal voa dlg ou f3k em sao paulo ou regiao de campinas.
Comprei um Versus e gostaria de construir e voar e depois alçar voo para outros melhores. Gostaria de saber quem poderia montar par mim

[Marcelo]

Sao Páulo Capital to atras de um pessoal tambem.

Fugindo um pouco, olhem isso

http://www.youtube.com/watch?v=WesBVBNwgrI


to pensando em pegar para brincar..treinar termicas pequenas..

[Lambreta]

[quote:b512e13162="Marcelo"]Sao Páulo Capital to atras de um pessoal tambem.

Fugindo um pouco, olhem isso

http://www.youtube.com/watch?v=WesBVBNwgrI


to pensando em pegar para brincar..treinar termicas pequenas..[/quote:b512e13162]

Pesquisem por F3XBrasil no face... entre em contato com eles.

Sobre este mini, se tiver um preço bem mais atraente que o Elf irá vender bem.
Já voei o Elf e chega a dar nervoso tamanho o despenho para seu tamanho.

[marcelowolf]

olá o que quer dizer com esta frase "chega a dar nervoso tamanho o despenho para seu tamanho".....é muito bom ou muito ruim?

[Lambreta]

É bom, pequeno daquele modo, mesmo leve, parece um DLG puro.

[Marcelo]

Pois é..deu vontade rs. Só desanima ver o preço do Binary 900 aqui, presumo que esse deva ser ainda mais caro..

[Lambreta]

[quote:6223b982ab="Marcelo"]Pois é..deu vontade rs. Só desanima ver o preço do Binary 900 aqui, presumo que esse deva ser ainda mais caro..[/quote:6223b982ab]

Eu ainda acho que compensa pegar um DLG usado, mais antigo (com 500,00 se compra coisa BOA pra voar, completo e em bom estado) do que um mini.

[fdcampello]

Gente, aproveitando a experiência e vocês, algum DLG tem asa bipartida baionetada ou todos tem a asa colada inteira?