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FT Flyer

d8veh

Well-known member
#1
I built two FT Flyers to run some tests. One had ailerons and slightly enlarged control surfaces and the other was a standard three-channel one. Neither had any downthrust and both had the thin wire pushrods mounted on the upper side of the rear fuselage, like suggested. They both flew OK, but both had a rather nasty trait that made them difficult for beginners. When they were given down elevator to penetrate the wind, they dived down in an almost suicidal way. They flew fine when going round with their nose slightly raised and using the throttle to adjust the height, but in the breeze today, they drifted down-wind, so needed down elevator to penetrate it.. I've been watching all the Youtube videos I can to see if others have this trait, but most are flying in calm conditions and I don't see the guys use any down elevator, except the one below, which shows the problem quite well. the pilot probably just put it down to himself not knowing how to control it, but that's what happened to mine except I didn't crash. I'm wondering whether it's something to do with the large flat wing or the rather thin pushrod.

I'm going to do some experiments to see if I can make it more acceptable. Has anybody else experienced this on the FT Flyer? Did you find a way to improve it?

See the dive at 0:55
Note they way it swoops down at about 1:10

 

jaredstrees

Well-known member
#2
I've only built a three channel version, but I didn't experience that type of behavior. does this happen when it is calm or just when the wind picks up?
 

d8veh

Well-known member
#3
It's not caused by the wind in any way because it'll do it in any direction at any time. A little bit of down elevator doesn't do much, but a bit more and the plane swoops down a bit out of control. It's no problem for an experienced flyer, although it's not a comfortable situation. The wind only contributed to the problem in that down-elevator was needed to penetrate the wind. On a calm day, you don't need to do that.

The transmitter is set with triple rates. I didn't risk going onto the high rates and the low rates were too low for this one. They're more or less the same settings as I have for many other planes, and I fly lots of different ones - normally at least one new plane every time I visit the flying field. On this visit I had three new planes. I therefore get a good feel for when something isn't quite right.

You can see the problem perfectly in the above video where he makes his first crash. He tried to level out a bit with the elevator, but the dive took him straight into the ground. Mine would have done the same except I always had more height.

I built the 3ch one specifically to test how easy it was for a beginner to answer a guy on another forum, so I let my inexperienced flying buddy do the maiden flight. I could see that he was a little bit out of control and not able to bring the plane back to the square without doing those terrifying dives, so I took the transmitter from him to bring back the plane. That's when I could see that the problem was in the plane, not the pilot.
 

jaredstrees

Well-known member
#4
hmmm. Well, I've got one that is just about done I was going to give to my son. Ill have to finish her up and see what happens. It'll be after Thanksgiving, but I'll let you know.
 

kilroy07

Well-known member
#5
I'm still a beginner, so I'm still learning so what I offer is just my observations and opinion of the FT Flyer.

It's a flat wing, so I think it has to have a slight angle up attitude Angle Of Attack (except maybe gliding in) to stay airborne.
I once tried a K2 airfoil but that was on my bomber version to yank a nerf football in the air... might be worth going back and playing around a bit more with that... (If I recall, I folded the wings in a high speed turn with a heavy bomb load) :unsure:

I had one that just flew very squirrely and couldn't figure out why... turns out the pushrods would flex... (after this I stopped using the thin wire) small changes seemed okay, but large movement would bind then snap to full deflection a second or three later (imagine how fun THAT was to try and bring home in one piece...)

I like the simplicity of the FT flyer because it gets you in the air with SOME success, but it's probably more of an "introductory to flight" than your main training aircraft (I'm leaning more and more to the tiny trainer for that.)

I guess my final take of the flyer is, it's ONE sheet of foamboard, you can have it cut and built in under an hour. It WILL fly for almost anyone (maybe not "Well" but it'll fly) and you can move the electronics when you are ready for a better air frame.

Hope this helps
 

kilroy07

Well-known member
#7
Oh, one more thing... When I first flew, I had WAY too much throttle! I was flying on a 2205 with a 3 cell...
(Yea, I KNOW now... that's a bit much on an FT Flyer, but I didn't then.)

It flew and was kinda a crazy ride, then I dropped the throttle to half and this wild bronco I was riding suddenly tamed down and flew quite nicely! I was amazed how little power it actually took and all that extra power just magnified every little mistake I was making (I was heavy on the sticks (like all beginners I suppose) in the beginning.)
 

SlingShot

Maneuvering With Purpose
#8
Looks like the throws are too extreme coupled with over controlling the aircraft.
If it were me, I'd reduce the throws (at least the elevator) by half and make sure I had 40% expo. Gentle corrections on the control inputs are the key.

Odd thing though, that video is from 2015....
 
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d8veh

Well-known member
#9
To me, the plane in the video just looked out of trim. Erratic behavior will happen If you have too much expo. A sharp leading edge or a tail heavy plane will be very sensitive to elevator.
I know what you mean, but that's not it. I have about 8 Flitetest planes on my transmitter plus two others. They all have more or less the same settings, as I just copy one to the next, then reverse any servos that need it. I've flown probably more than 100 different planes, and I haven't experienced this behaviour before. My Two FT Flyers (and the one in the video as far as I can see) exhibit the same behaviour, where they're over-sensitive to down-elevator. There's no problem with up-elevator. When you reduce the throttle, they're easy to control, except that they fly slightly nose-high and cannot penetrate a breeze like that. With reduced throttle, you fly with mainly up-elevator, and you control the height with the amount of throttle, so you don't see the problem.

There's two things I can think of. Its either the combination of zero wing incidence, the flat wing and zero down-thrust or it's the thin pushrod bending. The push-rod is pushing for down so you'd think that it would be under-sensitive if anything. The pushrod has a zip-tie brace on the 3 ch plane and two on the 4ch one. For the next flight, I'm going to try some downthrust on the motor and a stiffer control rod.
 
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d8veh

Well-known member
#10
OK, so I did a couple of modifications today. I added some strips to the wing top and bottom to blunten the leading edge, and I cut the nose to give about 3 deg of downthrust. If it's not to windy tomorrow, I'll test it.

FT Flyer wing mod.jpg
 

Merv

Well-known member
#11
The push-rod is pushing for down.
I think that’s your problem, the push rod is flexing on down. As the plane starts to go down, at some point, the push rod will straighten out. That sudden release of flex, could cause your dive. Try adding more supports (zip ties) to the push rod.
 

d8veh

Well-known member
#12
I was going to stiffen it, but when I checked it tonight, I found that it's already very stiff. It's very straight and has the zip-tie support in the middle. I left it how it is because I can't see it being the cause of the problem. I've convinced myself that the diving is just the behaviour of a large flat plate.
 

d8veh

Well-known member
#13
I tested it again today with the wing modification. It was difficult to tell whether there was any difference because it was quite breezy, but I don't think there was any difference. Again, it was OK with it's nose in the air, but you can't fly like that in a breeze, and when I opened up the throttle, it was very squirrelly. I tried a second flight with the expo cranked up to 60, but that only made it more difficult to steer because the breeze would knock it around so that large movements were needed to correct the plane all the time. I would add that I have a small hot motor with a small propeller. It would probably be better with a larger prop and a slower motor.

I'm going to try one more mod to get it to fly more like a normal plane, then I'll condemn it to calm days only. I'm going to scallop out the backs of the wings to narrow the chord.
 

Bricks

Well-known member
#14
If you take it straight up and hit the throttle what does it do? This is how I check thrust angle if it pulls to the canopy it needs down thrust, pulls towards the gear up thrust.
 

Paracodespoder

Well-known member
#15
I was going to stiffen it, but when I checked it tonight, I found that it's already very stiff. It's very straight and has the zip-tie support in the middle. I left it how it is because I can't see it being the cause of the problem. I've convinced myself that the diving is just the behaviour of a large flat plate.
Add reinforcements anyways. When placed under load (during flight) the wire has to push harder, this can cause a lot of flex. I built an ft bravo, and it has the servos on the bottom of the wing. It had hardly any response to up elavater due to flex. Trashed the airframe because it didn’t fly to suit my style.
 

buzzbomb

I know nothing!
#17
I know nothing. Is that perhaps the problem?
Suddenly found myself all :ROFLMAO::ROFLMAO::ROFLMAO:

If this weren't the internet, and posting a reply, you would have read "I know nothing, is that perhaps the problem?" Yeah! That's the problem! :p Laugh at yourself as much and as often as you can. It's good for the soul. :cool:
 

d8veh

Well-known member
#18
With scalloped wings, the FT Flyer looked fantastic. I was sure that it was going to fly beautifully, but the wind was very gusty today. Combine that with a crappy toss off, and the plane hit the ground before I had a chance to control it. Now the tail is separate to the wings and motor. It was bad day at the field today. I lost my new FT 3D too due to a stupid mistake. Only my favourite Sportster survived. I'll be spending the rest of the week practicing my right hand toss-offs rather than actual flying because the wind will stay until Friday. Can someone advise the best method of tossing off?



ft flyer b.jpg ft flyer c.jpg
 
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buzzbomb

I know nothing!
#19
With scalloped wings, the FT Flyer looked fantastic. I was sure that it was going to fly beautifully, but the wind was very gusty today. Combine that with a crappy toss off, and the plane hit the ground before I had a chance to control it. Now the tail is separate to the wings and motor. It was bad day at the field today. I lost my new FT 3D too due to a stupid mistake. Only my favourite Sportster survived. I'll be spending the rest of the week practicing my right hand toss-offs rather than actual flying because the wind will stay until Friday. Can someone advise the best method of tossing off?



View attachment 118845 View attachment 118846
Dang, dude. That sucks. Because I am a fifty-year old juvenile, I'm going to leave your question alone... Just a suggestion, though? "Hand launching a plane." Much better word choice. Just sayin' :sneaky:
 

Merv

Well-known member
#20
Can someone advise the best method of tossing off?
It depends on the plane, for tractors, I prefer the overhand football toss. For pushers, I prefer the Frisbee toss. The sidearm wing toss will work for both. Regardless of your preference, set the throttle at about 40%. It should have enough power to pull the plane out of your hand. Give it a firm throw, angled upwards about 20-30 degrees. If you use the Frisbee or sidearm toss, DO NOT induce a yaw, you need to throw them straight.