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Old Sep 26, 2012, 03:55 PM
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Kitchener, Ontario
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Originally Posted by Gerry__ View Post
Was the wind blowing? If yes, then at what speed?

http://www.rcgroups.com/forums/showp...19&postcount=1
It was pretty light today. Less than 5kph.
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Old Sep 26, 2012, 04:10 PM
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Originally Posted by rwelder View Post
It was pretty light today. Less than 5kph.
Do you find that it happens more in one direction than the other? Do you try to power out of it? (thinking torque might have an effect) How much aileron deflection do you have programmed? If the wind gets under a raised wing tip you are going to need that much more authority to get it back down. Definitely practice rudder turns with, if anything, a little opposite aileron to keep the wings level. it's not meant to be flown by "bank and crank" (aileron then elevator) it's meant to finesse it around the sky. Tell me your previous experience wasn't Q500s
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Old Sep 26, 2012, 04:25 PM
Drifting off the reservation..
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As far as spinning this plane, I don't think that is possible. I've tried to make it spin and the most you can get is a falling spiral dive.

I think folks sometime get too high on approach due to the shallow glide slope, and try to slow the plane down too much to avoid overshooting the field. Done it myself many times. That's why I went under the limbo poles and compressed one of my wings.
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Old Sep 26, 2012, 04:27 PM
Drifting off the reservation..
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Originally Posted by coreman View Post
and, dare I ask...

Were you turning downwind at the time and stalled due to maintaining your ground speed instead of airspeed?

Stirring up the pot! for shame for shame!!!
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Old Sep 26, 2012, 04:51 PM
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Originally Posted by JumpySticks View Post
As far as spinning this plane, I don't think that is possible. I've tried to make it spin and the most you can get is a falling spiral dive.

I think folks sometime get too high on approach due to the shallow glide slope, and try to slow the plane down too much to avoid overshooting the field. Done it myself many times. That's why I went under the limbo poles and compressed one of my wings.
That is what Crow is for!

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Stirring up the pot! for shame for shame!!!
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Old Sep 26, 2012, 04:59 PM
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OK, you were under power so you were not flying a glider you were flying it as a power plane. That changes EVERYTHING.

If you are gliding at low altitude and stall and hit the motor, that often results in crashing under power. Learn to deal with a stall without the motor.

But since you were flying under power, we can ignore the idea that you were flying a glider and gliding too slowly and stalled.

Having a brake is not an issue as you had the motor running when you went into the spin so the brake doesn't matter.

If you had the motor running before the spin you had airflow over the elevator and rudder. Doesn't help the aileorns but you would have elevator and rudder control. And, again, if you had the motor running when you went into the spin than you should have had enough air speed for aileron control too.

Wind can flip any aircraft on its side. If you were flying in high winds or gusty winds, especially if you were flying cross wind, the wind can flip your aircraft over on its side. Even with the motor on, if you don't have enough airspeed you won't be able to pull out at low altitude. The rudder can be very helpful here.

Naturally any airplane can be put into too steep of a bank at too slow of a speed and it will drop from the sky. Nothing unique here.

So, my conclusion from your answers is either you have a control surface problem or your flying technique needs some work.

Check to make sure your ailerons are working properly. Make sure the horns have not pulled out of the foam and that the control rods are working smoothly and that they are not flexing excessively when used.

Be sure the servos have not become loose in some way and that the control rods on both ends are solidly anchored in the control horn and servo horn.

Be sure the aileron hinges have not torn loose.

Finally, make sure you range check your radio before the first flght every day to be sure you don't have any obvious radio issues.

You may have posted this earlier but what radio, receiver and servos are you using? Is this a BNF or a plug and play configuration.




Just like any power plane if you have too little power and you pull up too steeply you will stall.
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Old Sep 26, 2012, 05:30 PM
Drifting off the reservation..
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If he had just a little power on, it could be that the prop was acting as an airbrake, slowing the plane below stall. Any power turns off the brake, and a low power setting can be similar to a windmilling prop.
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Old Sep 26, 2012, 05:53 PM
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Hmmmm. It sounds like we're getting to the bottom of rwelder's problem. I'm afraid that i don't have an RP so I can't offer instructions on setting the ESC to "brake". Most gliders claim to have the brake set as the default but I have managed to turn it off inadvertently while hooking things up for the first time or changing something. I'm still leaning towards simply getting too slow and trying to turn too tightly. Indoor flying would tend to get one in the habit of making tight turns that a 2 meter glider just can't match. And, as JumpySticks pointed out, using a little bit of throttle with a powered glider can do more harm than good.

In a general sense, one needs to plan one's landing approaches in advance and learn to do "go arounds" earlier than with a powered plane. Once one is familiar with a given glider it is possible to stretch a glide but even then it's usually best to get the plane level and then use a higher power setting to climb out and start the approach from scratch.
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Old Sep 26, 2012, 06:30 PM
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Originally Posted by rwelder View Post
I have flown RC for many years but am fairly new to sailplanes. I bought the Radian Pro and have crashed twice now. Both times, the plane gets into a fairly steep bank and I can't pull it out. Full opposite aileron doesn't seem to do anything and it quickly spirals into the ground. How do I correct for too steep of a bank without getting into a death spiral?

Does anyone know of a version of this plane that I can fly on my Phoenix sim for extra practice without having to use glue?

Thanks.
When you fly in a steep bank, you have to create more lift to stay level by pulling up on the nose, because the lift vector tilts. In a real aircraft the pilot automatically does this. But if he is flying slowly he can't so he must add more power. If power is not available, either the bank angle must be reduced or the altitude must be allowed to slip. If he doesn't increase speed or let the altitude slip the wing stalls. In a turn the stall speed goes up because of the increasing g's. The stall speed really starts to increase in level steep turns over 30 degrees of bank.

If you are flying an RC plane while rying to maintain altitude in a steep turn, you must do the same thing, pull up or add power. The problem is that when flying RC we are not in the aircraft so we do not see the nose of the aircraft and its relationship to the horizon, You don't have the same visual clues.

If you are flying an RC glider, the problem becomes more difficult. You are already probably flying close to the stall speed, especially while thermalling, and the natural tendency is to try to always maintain altitude even in the turn. You must fight against this and allow the nose to drop while in the turn to pick up speed unless you are in a very shallow turn. This takes some getting used to and is sometimes hard to judge because the plane may still be going up even with the nose lower if you are in one part of the thermal thermal but be going down with the same aircraft attitude in the weak part of the thermal.

In a light plane the standard procedure when you get into this pickle is to immediately relax the bank and avoid any stall. Its easy to sense it coming. You feel it in the controls and in your our butt. You could add power, but light aircraft just don't have the reserve to get you out of this. So you relax bank. But this probably isn't the best way to recover in an RC glider however because you may not see the stall coming and once you are in the stall, your ailerons won't do you much good. I'd say your best bet for recovery of a model stalled in a turn would be full power, neutral aileron, and a tad of down elevator. And if you need directional control, use rudder. Its effectiveness increases dramatically with prop wash. Take advantage of that.

Yeah, I know, just too much to think about when it is happening. Best to add a little more speed in turns (lower the nose), and watch the bank angle, especially near the ground.

Cliff
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Old Sep 26, 2012, 06:51 PM
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Thanks for all your suggestions and ideas. For the record the plane is BNF with a DX6i.

Took her out this evening to try and figure out where my issues are. I think the biggest issue is definitely my flying technique. I had some success this evening flying into a bit of a breeze off of a slope. It was a handful to control under power and tended to climb at a crazy rate into the wind. Gliding was better and particularly with a bit of altitude. I could have flown longer but my transmitter started to give me a low battery warning sound so I cut the flight short. Maybe 15 minutes in the air.

I checked things over again once I got home and it seems like I may have been tail heavy, (measuring 2 3/4" from the leading edge of the wing at the fuselage and then balancing the plane upside down on this spot.) I think that is weird since there is plenty of Guerrilla Glue holding the nose together but that could have contributed to the challenges I had been having.

I was hoping for a relaxing, fun sailplane did I buy the wrong plane?
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Old Sep 26, 2012, 06:52 PM
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Originally Posted by rwelder View Post
Not sure. 2 out of the 3 times I have been out with it I have found myself in a steep bank turn that I can't get out of. Seems fine until it gets into that death spiral. Do I need to use more rudder to control the plane? With my other powered RC planes you don't use the rudder much in the air and most turns are aileron/elevator controlled.
Two more questions that come to mind. Were flaps being used?? Why were you in a steep banked turn?? Getting ready to land? Getting ready to power up to altitude?? Well, that's at least two!
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Old Sep 26, 2012, 07:00 PM
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Wind can flip any aircraft on its side. If you were flying in high winds or gusty winds, especially if you were flying cross wind, the wind can flip your aircraft over on its side.
To say that a high wind crosswind can flip a plane is contrary to the concept (and fact) that the plane is moving IN the wind. It will not flip in a steady wind but can do so as a result of gusts or turbulence.
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Old Sep 26, 2012, 07:09 PM
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Originally Posted by rwelder View Post
I bought the Radian Pro and have crashed twice now. Both times, the plane gets into a fairly steep bank and I can't pull it out. Full opposite aileron doesn't seem to do anything and it quickly spirals into the ground. How do I correct for too steep of a bank without getting into a death spiral?

Thanks.
If the plane has stalled no amount of aileron control is going to bring it out. To do so requires differential lift, and a stalled wing has no lift. The only solution is airspeed and opposite rudder to stop the turn, assuming that the rudder has not stalled also. Some situations are not recoverable, which is why they are called death spirals.
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Old Sep 26, 2012, 07:22 PM
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I think that you will find the RP to be a "relaxing and fun sailplane" with a little experience and maybe a little tweaking of your setup. A powered glider with a lifting airfoil is going to climb under power. The faster you go? The more it wants to climb. I think you will find that correcting for it becomes second nature.

Cheers!
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Old Sep 26, 2012, 07:36 PM
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Originally Posted by peterlngh View Post
I think that you will find the RP to be a "relaxing and fun sailplane" with a little experience and maybe a little tweaking of your setup. A powered glider with a lifting airfoil is going to climb under power. The faster you go? The more it wants to climb. I think you will find that correcting for it becomes second nature.

Cheers!
Precisely, and this is a point that is often missed when guys first get a glider or have other expectations for the plane. Powered planes are designed to cruise level at some speed while flying under power. When you increase power they gradually climb, when you decrease power they descend.

Sailplanes are designed for thermalling without motor power. I fly my Radian typically for 2 hours with usually 5 power climbs of about a minute each. That is 5 minutes of powered flight for each 2 hours of total flight time. The only time you use the motor in a glider is when you need to climb to find the lift. That is what the plane is designed to do.

If you want to fly in some other fashion, you need to find a different type of plane. If you try to use the Radian/Pro for some other type of flying than for which it was designed, you will be disappointed and may even find all kinds of faults with the design that are really nonexistent.

Cliff

PS This is a general comment not directed to anyone personally -unless the shoe happens to fit you...
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