RE: Extreme Flight 87" Yak 54 - Build & Fly
Well guys, I finally finished my EF Yak... I've had it since March, but kept putting together profiles & foamies and flying them instead of assembling the Yak...
It's got the standard list of EF Yak parts... DA-50R, hitec 5945s on the rons / elevators, 8611a on the rudder... I used everything that came in the box... The only thing I replaced was the pull-pull system... I used some Dubro parts and the SWB adjusters instead of the stock hardware... I used the carbon control horns / servo arms, phenolic arm on the rudder... JR 10 channel PCM on the Rx... I loaded it up with Nimh batteries... #2 2700s on the Rx and #1 1800 on the ign... Just over a pound of batteries... I had a Tru-turn alum spinner, so I stuck that on it too... Mesjlik 23 X 8 CF prop... 16oz tank instead of the 20oz that came with it... Much to my surprise, AUW is 16lbs 4oz... Elle es gordita... She's a little fat, but what the hell...
All in all, it was a very straightforward build... Everything fit, no foobar'd parts... This one was one of the ones that had a "twist" in the fuse / stab / posterior region... I found the twist back in March... I stuck the airframe together and hung it from ceiling in my garage... I guess 115 degrees for a couple months does wonders on drying out a fuse, cause when I pulled it down to start work on it 3 weeks ago, the twist was amazingly gone... Go figure...
All I can say is that this is the sweetest airplane I have ever gotten my hands on... Flies like a giant kite... Almost better than sex... Well, almost...
I didn't find any bad habbits other than the fact it doesn't want to land... You gotta bring it in real flat and then just about stall it to get it to land...
Did have some "issues" getting the DA50 to start, but that was all me... Had to learn the SOP on starting a DA 50... Too much fuel and it'll flood every time... Finally got it down though... ign on, choke on, flip till it pops... Then choke off, 4 clicks of throttle and starts on the 4th or 5th flip... Nothing like 40 - 50 flips at 97 degress and 100% humidity to suck the life out of you...
During the maiden we kept hearing a metalic sound on throttle-up, so I cut the first flight short... When I was doing the post-flight check, I found that the muffler bolts backed out and the muffler was just hanging in the cowl... These were the only bolts that I didn't locktite... doh!!! Lost one bolt, so I scrounged a new bolt from a buddy, made a new gasket and locktited the bolts the second time... Started it up, let the engine get hot, then tightened the bolts again... No problems after that...
Every manuever was like it was on rails... KE was clean with zero coupling... Harriers were rock solid... Blenders were mind boggling... Once inverted and spinning, a little throttle it would hang in the air spinning and maintain altitude... Amazing... Inside & outside loops were perfect and rolls were very axial with no aileron differential programmed in... On kill rates, the rolls are sooo fast that you can't count them... Hovering was like a puppy dog on a leash... Just stand her up and make minor corrections... Snaps were very clean and stop on a dime, except for positive snaps which over-rotated some... Elevators were good with a decent sink-rate with a little throttle... Little or no wing rock... Didn't try any waterfalls or pinwheels... I tried to make her snap-out several times just to know where to expect it and never was able to get her to drop a wing, no matter how hard I pulled... I did most of this up high as I didn't want to dork her on the first day, but I'll keep working her lower as my confidence increases...
As far as the dual battery packs, I was being anal about redundant power and I'd read too much about battery impedience at max C causing brown-outs on the Rx... Since I'm running PCM, I didn't want to chance a lock-out scenario and lose the plane because of it... I'll probably yank out one of the packs after a few flights... But to be honest, it flies sooo well just the way it is, I may leave it in...
And YES, I taped my xtal into my Rx... Lesson learned Wayne...
It's too bad that EF / Chris are having problems with their manufacturer for these airplanes... They are simply amazing... Hopefully he will get these issues straightened out so more people can enjoy this amazing airplane...
Here's a couple pictures...