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Old Dec 03, 2012, 08:40 PM
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From my point of view he came in way too hot. After some radical moves to slow him down (nearly crashing) he settled into a clean glide and a nearly perfect speed for a reasonably good touchdown. It looks like a maiden flight where the pilot has no idea what speed to land on, which this jet can do if you are not familiar with it; keep you guessing. What I would suggest to anyone who maidens is to make only a pass or two to trim and then concentrate on what approach speed to land with with the other passes so you will be less surprised when you come to the real landing. Set the timer to minimal, like 2.5 minutes or so because you may well go over that time limit with aborted landing attempts and DON'T keep a super high speed during the majority of the flight; keep it fast enough not to stall though; you want to save as much of the battery as possible.
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Old Dec 04, 2012, 03:35 AM
CSI
I promise, just ONE more order
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Del Rio Intl, Texas, United States
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I think Urrl's advice is the smartest thing I have read. I know I am going to follow his advice if I ever get my plane finished. Risking a deadstick with a new plane that weights in at this level is just asking for trouble. ....been there, done it too many times!
Nice discussion guys, learning a bunch about this plane.
Ken
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Old Dec 04, 2012, 12:14 PM
Fast Jets for Fast times
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St. Peters MO.
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Urrl,

Agree with your flight plan. I guess when I looked over the l-39 flight that guy did it wasn’t that bad. I do think there are refinements even on such a nice kit like this one. You certainly have the most experience I have seen with this jet and have been a huge help with your video flight progression. I have a sport 70mm that has been my high speed landing trainer that has help me with controlling a faster jet for approach and controlled landing. You will get a kick out of a 90mm my brother and I built a few years ago. My brother fly’s this one. Its way over my skill level right now but we use your same approach when doing a maiden. I hope the L-39 give me the experience in to the larger jets. I have a few more video’s on my U-tube with some success and some failures but always learning.

The resolution sucks, I set it to low when I uploaded it.

F 105D Thunderchief re maiden 0001 (5 min 10 sec)
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Old Dec 04, 2012, 06:43 PM
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Thanks for that video. Love the build pics; great looking jet. I hope your L-39 maiden goes well. Mine is still in transit and should be here this coming Tuesday.

My biggest problem is not appreciating my jets and becoming reckless after having them a while. Putting a 6S battery in an 8S system did work on a smooth long runway just barely but when I took it to Orlando and tried taking off on a very rough area it caused me to wreck my last L-39 and I miss it.








When I think of all the work I put into it and how carelessly I finally treated it...Oh well, let's hope I've learned my lesson.
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Old Dec 05, 2012, 09:12 AM
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Question for 6S-5xxx Setup Users:

Where about will be battery position approximately ?
Can you pls post a picture with the battery in "flight" position ?
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Old Dec 05, 2012, 03:34 PM
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Different 5000mAh batteries may have to be placed differently according to weight and shape. That is why I would never try to use another pilots battery position. Also he may have a heavier motor and a metal fan housing; this would throw the other guy's battery position in your jet way off if you tried to balance the jet according to CG. What is important is that you should FIRST have the correct CG points marked on each wing; at least that is how I do it, perhaps with a small triangular piece of tape. The battery should be positioned where it will generally balance the jet when you hold the jet by the cg points on each wing.
Again, here is an addendum added by Scaleflying concerning the CG for their L-39:

*Notice
The CG point in the manual is not correct. We have found that the correct CG on this aircraft is 55mm from the LE, measured 24cm out from the wing root.
Please disregard the manual and use our suggested CG.

http://www.scaleflying.com/Aero-L-39...an_p_2522.html


I may mark the inside of the cockpit once the correct battery position is found but I will always check that position by physically balancing the jet with my finger tips, using the CG points marked on the wings before taking off. I have different 6S batteries with different shapes.

In any case this is the only pic I can find for my 6S set up but as I recall the arrow marking I drew which marks where the butt end of the battery position was for my 6200 mAh battery, not the 5000 mAh battery shown, which was "I think" a half inch more forward toward the nose... but I cannot swear to that.


The motor was a stock 1900kv with stock a non metal 6 blade ChangeSun fan.
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Old Dec 05, 2012, 05:42 PM
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By the way I don't know if there are any other comparable deals for a 60C battery
http://www.valuehobby.com/power-syst...h-6s-lipo.html

I do have two 60C 4800 mAh Gens Ace and two 5000 mAh 60C Gens Ace batteries which work very well with this type of jet but I got them on sale.
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Old Dec 06, 2012, 02:33 AM
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I've never fitted pin hinges on flaps before, can someone post a picture of how they should look on this bird or advise me please
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Old Dec 08, 2012, 02:05 PM
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Sorry Hixxer I don't have my jet yet, although my landing gear and servos came in today from Hobbyking


The landing gear springs feel much stronger that my previous stock ones with the plastic bases.
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Old Dec 09, 2012, 07:55 PM
Fast Jets for Fast times
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St. Peters MO.
Joined Nov 2007
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I completed the bench test of my CS12 blade 90mm I got from X-flight for this jet. My first test using the HK Red Brick 125amp ESC timing was set to a 30deg that provided 22.5V 95A 2137 Watt with a thrust of 6lb 3oz. I dropped the timing to 7deg and got 22.5V 91A 2047W at 6lb 1oz. I will leave it at the low timing so when I use a higher C rated I won’t over amp it. I got it assembled with only minor servo adjustments needed and the total weight is 8lbs with a 35C 4500MA 6s batt.

CS12 blade 90mm X Flight assembly (2 min 25 sec)
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Old Dec 10, 2012, 09:59 AM
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Expecting the L-39 to be delivered today. I have decided to use my trusty Walkera RX2702V receiver which came from my Walkera 450 flybarless heli and has been proven to auto stabilize my little Airfield F-15 on many flights.
Airfield F-15 with auto stabilization (1 min 36 sec)


The L-39 is a smooth flyer, nevertheless in windy conditions I suppose every little bit of control helps, and there is a smoother flight in calm conditions also, a good thing for an on board camera.

The package just arrived in great condition and the contents look undamaged.





Packaging is decent but has no styrofoam reinforcing so it could be better. Delivery was USPS

I see the manual is not corrected; the 77mm-82mm should be 55mm (to 60mm?). This means the battery will have to be moved more forward toward the nose to balance the jet. So the manual CG makes to jet too tail heavy.
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Old Dec 11, 2012, 01:30 AM
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Quote:
Originally Posted by Hixxer View Post
I've never fitted pin hinges on flaps before, can someone post a picture of how they should look on this bird or advise me please
I just use epoxy for the pins. First I had to cut the servo rod a bit. Once Everything fit, the servo was tested and the arm adjusted, the servo rod connected to the flap and the flaps were taped in place I applied epoxy to the pin ends and inserted them.








Those landing gear I posted earlier do not fit. I will have to do some dremeling tomorrow. Also those metal servos do not fit well; took too much time making them fit.
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Old Dec 11, 2012, 02:31 AM
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Thanks for the piccys Urrl, I will get my flaps done now
Finding landing gear for this bird is a pain in the a55, I have ordered two sets now, neither seem right without major mods to the gear. Ah the joys of RC
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Old Dec 11, 2012, 03:52 AM
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AFIK these are drop-ins LDG units...
http://www.hobbyking.com/hobbyking/s...Hawk_L_59.html

Gotta kit, but those were intended for the Hawk, choices, more choices
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Old Dec 11, 2012, 04:28 AM
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They are no longer stocked, the alternatives have a double front wheel and look too short
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