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Old Jun 08, 2010, 02:49 PM
Houston. .we have a problem.
FOX ONE!'s Avatar
United Kingdom, England
Joined Aug 2008
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Anyone flown their birds recently?
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Last edited by FOX ONE!; Jun 22, 2010 at 12:42 PM.
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Old Jun 23, 2010, 09:53 AM
Registered User
hklagges's Avatar
Munich
Joined Dec 2008
1,173 Posts
Quote:
Originally Posted by abagnalejr123 View Post
Anyone flown their birds recently?
Check out this guy here:
http://www.xwing-crew.ch/index.php?o...86&video_id=34

Cheers,
Henrik
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Old Jun 23, 2010, 10:11 AM
Ready to fly MRs
Sid3ways's Avatar
Swanton, OH
Joined Jul 2007
5,082 Posts
LMAO, who needs a dolly when you can take off on the gear and jettison it after takeoff?
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Old Jun 23, 2010, 11:02 AM
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London
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What the hell happened there? Why did it dip so much after take-off?
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Old Jun 23, 2010, 11:26 AM
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hklagges's Avatar
Munich
Joined Dec 2008
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Quote:
Originally Posted by Jammo View Post
What the hell happened there? Why did it dip so much after take-off?
Probably overcontrolling... with all these control surfaces the Su-47 is incredibly agile.

Cheers,
Henrik
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Old Jun 23, 2010, 11:56 AM
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London
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Makes sense.
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Old Jun 23, 2010, 03:35 PM
Ready to fly MRs
Sid3ways's Avatar
Swanton, OH
Joined Jul 2007
5,082 Posts
Looked like it needed an insane amount of trim and the elevators/canards weren't at the right neutral angle to begin with. Either that or he put a cinder block under the canopy.
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Old Jun 30, 2010, 04:48 AM
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Joined Jan 2010
78 Posts
Awesome with the cow's bells in the back

It gives a godd idea of switzerland lol
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Old Jun 30, 2010, 07:59 AM
Fly, Crash, Burn,
f4addict's Avatar
United States, CT, Danbury
Joined Jul 2008
667 Posts
Mtn_commando, how did your maiden with tuning gyro's go?

The guy in the video was trying to loose some weight off the plane so instead of doing all the hard word, he found a easy method. Just rip the landing gear and doors off.!!!:-)
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Old Jun 30, 2010, 09:17 AM
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United States, CA, Dublin
Joined Sep 2008
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No maiden yet, been unable to find time. Will post a report as soon as she takes to the air.
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Old Aug 01, 2010, 02:55 PM
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United States, CA, Dublin
Joined Sep 2008
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Ok gentlemen, I finally maidened her yesterday. The delay was because I was looking for a paved runway. I finally joined a club that has one.

Actually, I had cold feet so I asked one of the field experts to maiden her. AUW was 2750 grams. All gyro gains were at 0%, and thrust vectoring was kept off.

First takeoff was aborted because she ran out of runway (around 100 feet). Ran into the grass and that caused the front retract to dislodge. With some 5 minute epoxy, she was ready to go again.

Second takeoff, we started right at the beginning of runway, allowed her to pick up good speed and lifted off like a rocket in around 150 feet. VERY tail heavy, said the pilot! Also very touchy on the controls. We knew immediately that we had to bring her back down, the pilot was struggling to keep her under control (and he's a GOOD pilot). Power was enough, but it was way tail heavy and that made it very hard to control. Easing back on the throttle caused her to nose up dramatically, almost looking like a cobra .

Anyway, he was finally able to get her down. Landing was a little rough, she came down almost vertical on her tail. Thrust vectoring nozzles dislodged and both of the rear retracts snapped right at the wheel. But the rest of it is unscathed.

So, looks like I overcompensated for the CoG. I had it at about 3.5-4 cm (so 1-1.5 cm behind factory setting), and that was definitely too much. On a positive note, the repairs are easy. Looking forward to getting her back in the air next weekend. I'll be extra careful to keep CoG exactly at 3cm.

She was definitely a head turner though
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Old Aug 01, 2010, 03:09 PM
Flying Hazard
SU-4ever's Avatar
Spain
Joined May 2006
3,034 Posts
I'd have used the gyros.

That's the trick on Tail heavy planes!

Good to know it lives to fly another day, better luck next time!
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Old Aug 01, 2010, 03:37 PM
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hklagges's Avatar
Munich
Joined Dec 2008
1,173 Posts
Hello there,

thanks for the field & damage report. Some comments below.

You can shorten the takeoff distance enormously by switching the TV nozzles on. With them, you can (or at least I could, and I have a Su-47 with a similar AUW as you have) rotate after 10-15 meters (30-50 feet).

Regarding the tail heavyness: This plane seems to be really tricky. You had it at "1-1.5 cm behind factory setting". When I tried it at 1.5cm behind factory setting, it was tail-heavy as yours - terrible. But when I had it at the factory setting, it seemed nose heavy to me - where is the sweet spot? Maybe some pre-trim of the control surfaces (canards 3 up, elevators 1 down) would help more than moving the CoG backwards?

Regarding the touchyness on the controls: Absolutely. It is easy to overcontrol it. I am considering to remove roll from the canards and elevators and have it only on ailerons and tv nozzles.

The head-turner effect is there, but that means there is even more pressure on the pilot!

Cheers,
Henrik
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Old Aug 01, 2010, 03:40 PM
Flying Hazard
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Spain
Joined May 2006
3,034 Posts
Leet's see what happens with the Gyros, I'm really interested in your results!
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Old Aug 01, 2010, 04:10 PM
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United States, CA, Dublin
Joined Sep 2008
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Hi Guys,

Thanks for the feedback. SU-4ever, did you mean you have used gyros on this plane? Or on some other plane? How were your results?

Henrik, since 2.5 cm is too forward, and 4 cm is too far back, I guess the logical thing to do is keep it at 3.25cm. Have you managed to work out a setting that somewhat works? I think i'm going to reduce throws by 50%, maybe increase expo from 35% to 50%
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