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View Full Version : Discussion Freewing L-39 Maiden


mike__
Jan 25, 2008, 06:28 PM
Just maidend my L39. Conditions were perfect, no wind which is strange for Perth. This is my first EDF plane after flying my PZ supercub for a while and my PZ T28 about 10flights. Neither have been crashed *knocking on wood*

I built the plane over 4 nights and encounted a lot of dramas & did a few modifications. My wings were a less than perfect fit, i had already applied the epoxy and was left with gaps 2/3mm along both wings. What a nightmare. Anyhow i learnt my lesson and after a little sanding the rear end assembly was a perfect fit. Did a few modifications: Ran a piece of servo wire across the back stabalizer to join them 2gether to create a stiffer piece. The wire sits directly behind the thrust exit and using heat is molded into place then epoxied. Also i fixed the rudder with epoxy and siliconed the steerable nose in place. Where i fly is all grass, never use the steering on any of my planes. Saved a little weight here to compensate for the amount of epoxy i used everywhere strenghtening nearly everything and every join. Im yet to weigh the plane but i think it will be over so i wasnt too confident with the maiden.
Used my PZ ZX10 TX from my T28 set on low rates, PZ rx (waiting on a corona dual), batan servos and a 30amp esc supplied my extremerc. Battery is a chinese xcharge i got of ebay: 15c 1800. Is crappy i know but does the job fine until i buy a better quality one. You can get this plane as a package. Aerilons & elevator were set on low travel with the servo/elevator holes. Paint scratches fairly easily on the foam (prefer elepor), but paint job was excellent

Confidence was a little low this morning as i put her on the grass for a ROG takeoff. Grass was rough but not long. Heart was beating hard, no wind at all, gave her full throttle and she screamed off taking off a lot sooner than i anticipated, about the same distance or less than my T28 (<10m), i couldnt believe it! She climbed pretty steep and needed down trim. This was adjusted on the plane after the flight.

This plane is one SWEET beginner EDF. Actually found it a little easier to fly than the PZ T28 (which i absolutely love), or maybe its cause i learnt aerilons with that plane. Im sure plenty of you have seen the HL F-18 videos, how easy it glides and can fly @ very low speeds on v low throttle. This is exactly the same. Can fly in a very small area and the plane turns on a dime! Can 'hover' along very slowly and turn 180deg so quick, couldnt believe it! Rates and travel were all set to nearly the lowest positions, which im glad i did. Rolls were easy and smooth, NOT lightening fast (im not an advanced flyer) and she performed loops effortlessly but did slow down a ltitle at the top of a large roll.

Speed was a little dissapointing & identical to the T28 but am sure a better battery would fix this. Seems identical to the HLF18, whilst not slow i am used to it and need a little more speed, after all it is a jet :) . Sounds awesome in the air but not too loud but it looks terrific! Flight time im guessing was ~6min or so using mixed throttle. I have to get used to the decreased flight times because i was actually away in the distance when she lost power fairly quickly. Bought her back and landed a tad heavy in an emergency landing. I shouldnt have cut the throttle which im used to do on prop planes near the ground and the landing gear bent v slightly. Might even ditch it which will help the speed but this plane seems like itll need x2 hands to hand launch & i love rog takeoffs.

I can now see the hanger getting bigger.......

Mike

FASTBEN
Jan 25, 2008, 07:12 PM
good news mike glad to see you enjoing the EDF, now come to the darkside.LOL
ben

Extreme_RC
Jan 25, 2008, 08:06 PM
Good to hear the flying part is everything its claimed to be! :)

As for building, DRY FIT!! Always dry fit everything, adjust, sand, trim, dry fit again, when its all lined up only then glue! :D

I agree the setup of servos inside is very fiddly, I think it will be better to import them with the servos already fitted ready to go. The servos will not be as good as the ones you have in yours, but shouldnt be too much concern in this plane.

The ESC is set to hard cutoff, so if the throttle cuts you need to close throttle immediately, then you can open it up again partway and you should have enough power to come round on half throttle and land.

Its designed to have thrust over exit velocity, perfect to start off on EDF. A cheapy ebay pack of 15c will definitely be sagging out in that power system, the motor wants around 25 amps and most 1800 15c ebay packs will be lucky to hold 10v at 20A. once you have a known quality 20c+ pack in there you will need to watch ambient temps and make sure you dont overheat anything, the increase at the fan in RPM will be very noticeable though!

Hand launch should be quite easy, hold the fuse behind the wing and javelin throw straight out nose very slightly up using full throttle, she should fly out of your hand without issue. Main thing is firm push and keep it straight as it leaves your hand, the rest will then be pretty easy.

darmar
Jan 25, 2008, 11:50 PM
Mike, great news.
Can't wait to get hands on mine.

mike__
Jan 26, 2008, 01:58 AM
Mark: i was dry fitting the wings, got half way in & was getting tight, figured they look like they should line up right then used the epoxy. Was cursing to say the least. The ESC didnt cut off (did during testing with a flat battery), power dropped (probably was about to cut off) off and i did a rush landing.

So a unit with less impellers and higher rpm would give more velocity? I bought a Flightpower Evo25 pack in 1800mah 2day (had a xmas voucher otherwise would have bought one of yours). My charger only has an outlet for a hyperion plug and some other style but not the one fitted dammit. Have to sort that out, but cant wait to try it out. I know removing the landing gear will help speed but i think it might aid in keeping the plane level by having a little extra 'low down' weight??.

Temp was not really an issue apart from the hot battery, but will keep an eye on things with the FP pack thanx.

These edf's are very addictive, my fiancee already hates this plane, especially once i discovered our kitchen benchtop makes an ideal work platform :)

mike__
Jan 28, 2008, 05:55 AM
For those wondering how it flies. This is stock with a FPevo25 1800 pack

http://www.youtube.com/watch?v=-gfa7Wg1KY8

http://www.youtube.com/watch?v=y03TsdvZCtU