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FT LongEZ First Flight - Not at all what I expected.

JasonK

Well-known member
#1
I built a FT LongEZ yesterday and took it out today with a 2Cell, 6x3 prop on an A Pack motor. I got the CG were the plans said to do for RC option. Trying to figure out what I might have done wrong. First 2-3 tosses didn't go anywhere (just belly flopped), so I had my son throw it with the throttle up at 100%. This got my off and flying but I had to hold back ~80% (low throws 30% Expo) to just keep altitude. I did manage to make a slow left loop, getting the plane 200ft? away from me around the loop. When it got bake near me it was coming straight at me (and still hadn't got much altitude), I tried to make a sharper turn, but dropped it from the sky. It was flying somewhat nose up the whole time.

I tried moving the CG back slightly, but that didn't help much and just made it less controllable, didn't help with the up elevator needs.

One thing that supprized me is that it actually flew fairly smooth (other then the hard up need), keeping it level in the roll direction was fairly trivial, and the bank/yank turns were rather smooth.


I am curious if anyone has any idea what was going wrong with the flight (sorry no video) or suggestions for things I should check.
 

mrjdstewart

Well-known member
#2
you need some reflex in the elevons. this is typical of plank style airplanes. go into servo setup on your transmitter and adjust the sub-trim so you are almost a full FB thickness up. keep the CG the same and try again.

i have never been a fan of the EZ, but that's just me.

good luck,

me :cool:
 

JasonK

Well-known member
#3
I had already put in the Reflex requested by the plans (this is the elevator neutral position). Are you thinking that this is insufficient?
FTLongEZReflex.jpg
 

Merv

Well-known member
#4
This got my off and flying but I had to hold back ~80% (low throws 30% Expo) to just keep altitude.
Sounds like you need more up elevator. Once you get the plane trimmed to fly hands off, it will fly much better.
I’d move the CG back to the original place. CG has more to do with stability not setting the pitch of the plane.
 

CarolineTyler

Well-known member
#5
Built two of them, hated them both. Poor flyer, breaks it's canard on almost every crash, of which there are plenty. The flat profile wing is super pitch sensitive.
 

JasonK

Well-known member
#6
Interesting that you broke the canard all the time, mine just 'floats' down and belly lands when I cut the throttle. I was out at an airfield today and tried to fly it a few times, with a 3 cell it had plenty of go, even made most of a circuit before coming down (had issues on the turn into the wind/far away from me, need to make the turn tighter corner). Then eventually had issues with it climbing hard when the throttle was high, but when I cut it, I had a fairly controllable glide slope.

I also noticed that my power pod was slightly loose, and given the sensitivity of the plane, I wonder if that was part of my problem (thrust angle shifting). One of the guys at the field said that if it glides ok (which it seems to) but was climbing when the motor was on, I probably had a thrust angle issue.

I am debating if I am quite ready for this however, it is _very_ sensitive on the controls, ended up with 50% EXP and my dual rates were turned down quite a bit toward the end there. I might just go back to a tiny trainer for a while... get better at flying (I think my son might have passed me on the Tiny trainer here) and get back to my 'crazy' designs after I get better at flying.
 

Tench745

Well-known member
#8
I don't have experience with the FT LongEZ, but with a flat plate wing you will generally need a greater positive angle of attack for the wing to generate sufficient lift. If you glide test and it floats down without diving steeper or pitching up it means your airframe is trimmed correctly for the current CG. If the aircraft is particularly pitch sensitive you can move the CG forward and you'll have to re-trim the aircraft to get that nice power-off glide.
If it glides well but becomes unmanable with power on, it means that somehow the motor/prop/thrust is the issue. Typically if it pitches down when you add power it means you want to add some up-thrust. If the plane pitches up when you add power you want down-thrust.
If your problem seems to swing either way ie. sometimes pitching up with power, sometimes down; then you'll want to look for slop in the motor mounting and the controls. A loose power pod like you have, and/or pushrod flexing has perplexed more than one builder, myself included.

I will say that, for me, 50% expo is too much. The controls start feeling sloppy and you lose the feeling of how what you're doing on the sticks affects the aircraft. It becomes really easy to keep pushing the stick further and further to get the effect you want and then suddenly you get out of the softened region of the Expo and you over-control. For me, if I have expo much above 30% it means I need to reduce the throws either mechanically or by adjusting rates in the transmitter.
 

JasonK

Well-known member
#9
I don't have experience with the FT LongEZ, but with a flat plate wing you will generally need a greater positive angle of attack for the wing to generate sufficient lift. If you glide test and it floats down without diving steeper or pitching up it means your airframe is trimmed correctly for the current CG. If the aircraft is particularly pitch sensitive you can move the CG forward and you'll have to re-trim the aircraft to get that nice power-off glide.
If it glides well but becomes unmanable with power on, it means that somehow the motor/prop/thrust is the issue. Typically if it pitches down when you add power it means you want to add some up-thrust. If the plane pitches up when you add power you want down-thrust.
If your problem seems to swing either way ie. sometimes pitching up with power, sometimes down; then you'll want to look for slop in the motor mounting and the controls. A loose power pod like you have, and/or pushrod flexing has perplexed more than one builder, myself included.
This is what someone on the airfield told me, give it a touch of down thrust (it was pitching up, nearly uncontrollably when under power)
I will say that, for me, 50% expo is too much. The controls start feeling sloppy and you lose the feeling of how what you're doing on the sticks affects the aircraft. It becomes really easy to keep pushing the stick further and further to get the effect you want and then suddenly you get out of the softened region of the Expo and you over-control. For me, if I have expo much above 30% it means I need to reduce the throws either mechanically or by adjusting rates in the transmitter.
Yup, that is what I realized afterwords, that I should have turned down my dual rates instead of the expo. Either way, it is sitting on my shelf until I get some more practice in with a Tiny Trainer.