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Harrier flattens out

#1
Hi Folks,
I just picked up a hobby king Reaktor 3D. It's my first real 3d plane and I'm having a blast with it. When I try to get into a harrier though I find that it wants to level out even though I am applying full back elevator. What am I doing wrong? Is it the plane's CG? Do I need more elevator authority? More throttle?

Any tips are appreciated :)

Thanks
 

xuzme720

Dedicated foam bender
Mentor
#2
Probably CG. The Reaktor seems to like a very rearward CG. Mine is actually too far back at the moment so it harriers almost by itself. (Not that I'm any good at them! I have found this plane can take a beating!) Of course, in any kind of wind all it wants to do is climb and is very pitchy so I will have to move it forward some before I put it in TOO hard and don't have a Reaktor anymore.

Just keep bumping it back until you get somewhere you like.
 
#3
Do you have weights in the tail? Or did you move any of your electronics backwards?

I probably do have the CG too far forward, I haven't actually checked it. It flys awesome, perfectly straight and level, but I know it's designed for a pretty light motor/battery combo and I'm running a D2822 and 850mah 3S which I think is quite a bit heavier than recommended.
 

xuzme720

Dedicated foam bender
Mentor
#4
I'm using a 28 series motor, I think it's a Firepower 450 IIRC and a 1300mAh 3s. I made a cutout just over the wing to hold the battery and I have the ECS in the old battery hole. I just moved it there but CG's too far back now.
I always try to move stuff before I add weight. With these foam planes it's pretty easy to just cut a hole if you need a different location to place gear. If it doesn't work, just glue the piece back in and try somewhere else. Just be sure to cut carefully and hang on to the cutouts!
 
#5
I moved the lipo back quite a bit, almost right over the CG. CG is at 85mm from the leading edge as the manual suggests. It seems to have helped though I'm getting a lot more wing rock than I was before. I was able to get into a hover a couple of times today but holding a harrier is tough because I feel like I'm constantly correcting for the wing rock. I'll keep playing with it :)
 

Ak Flyer

Fly the wings off
Mentor
#6
Even 3D planes should have a neutral center of gravity. I kept mine towards the rear when I was learning, but the more research and practice I did the more I realized how important it was to have it centered. It will hover easier with a rearward cg but it's going to hurt it in other areas. Like any other aircraft it requires balance to do all around 3D.

Besides that, check your throws. How much are you getting out of it? It takes quite a bit to pull into a hover when flying slowly. If you are cruising and pull it straight up and then back off the throttle, does it still want to nose over? Could be a thrust angle problem.
 
#7
If you are cruising and pull it straight up and then back off the throttle, does it still want to nose over? Could be a thrust angle problem.
Before I moved the battery it would nose over in that situation, now it sometimes does but sometimes it will fall backwards or to the side as well. What should it do?

I will check my throws. I don't have a good way to measure them but I will figure it out. I have a feeling I'm not getting as much elevator throw as I should, though I'm also not sure how I'm going to increase it with the the pull/pull thread system.

Thanks for the advice :)
 

Ak Flyer

Fly the wings off
Mentor
#8
Post some pictures of your setup. Pictures at full throw up and down would help. What radio are you using? You can adjust your servos to go past 100% on spektrum radios. To adjust throw mechanically on a pull pull, you just move the thread to a lower hole, just like you would a pushrod. You have to move it on both sides though.
 

xuzme720

Dedicated foam bender
Mentor
#9
Even 3D planes should have a neutral center of gravity. I kept mine towards the rear when I was learning, but the more research and practice I did the more I realized how important it was to have it centered. It will hover easier with a rearward cg but it's going to hurt it in other areas. Like any other aircraft it requires balance to do all around 3D.
Yes, I went past the rear of recommended cg and it sure showed! I think I might be having some thrust angle issues as well but it's just one of many things I am working out on multiple models at the moment. I always seem to bite off more than I can chew...
 

Ak Flyer

Fly the wings off
Mentor
#10
it's just one of many things I am working out on multiple models at the moment. I always seem to bite off more than I can chew...
Tell me about it. I'm trying to decide how best to thin down my fleet. I'm big into the nitro helis right now, I still have nitro planes, electric helis, electric planes, rock crawlers, pretty much everything but multi's and fpv at the moment. I want to build a big tri copter but I have to get rid of things first.
 
#12
Tell me about it. I'm trying to decide how best to thin down my fleet. I'm big into the nitro helis right now, I still have nitro planes, electric helis, electric planes, rock crawlers, pretty much everything but multi's and fpv at the moment. I want to build a big tri copter but I have to get rid of things first.
I'd take that super cub float plane off your hands if you're interested :)
 

Ak Flyer

Fly the wings off
Mentor
#13
I'd take that super cub float plane off your hands if you're interested :)
The Super cub is about as hammered as you can get. It's got weird tendencies now, the flaps are more like brakes, it's waaaay faster than stock but also has to fly faster because it's quite a bit heavier. I was out flying again the other night with my friend who hasn't modded his as much and his is way slower, more like stock. The cool part is I can carry a payload nearly straight up as far as I want to drop with the bomb drop. It's really a beater plane that I wouldn't wish on others. Most of my stuff that I got when I was learning is not in condition to sell. It's more of what am I going to give away, what am I going to trash, which am I not going to put money into any more. My Galaxy has already gone to the trash pile, my hawk is about to, My MCPX is going to be a birthday present for my brother I think. I got a MSR and a bunch of parts to sell, my MCX2 I'm trying to sell, then my big stuff. I'll probably keep the super cub forever. I may sell my nitro cub after I recover it the rest of the way, my Fourstar 60 still needs the wing finished and a new engine, might just recover it and sell the air frame. Then there's the Ember. Needs a new frame to be able to fly or sell. The micro 4Site is my last indoor plane. I'll revive it for the winter.

Okay, not sure why I'm rambling on about all that. Thinking out load and typing I guess.

So anyway, how the Reaktor coming? Lol.
 
#14
I'm using Turnigy TGY-1800A servos. I just measured my elevator travel and I'm getting about 55mm of travel, where the manual says it should be 70. I can see that I'm not maxing out the "notch" in the tail.

Is my control horn backwards? I couldn't quite make it out in the manual and at the time I thought this would give the most throw but now that I'm looking at it I have a feeling it should be the other way :eek:

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