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Old Jan 23, 2011, 11:47 AM
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Originally Posted by G202flyer View Post
Arlyn
I wouldn't trust those batteries at all. FYI the Yaks like to be balanced just a liittle on the tail, easy to handle and they roll better. My 42%ers are about 1-inch back of normal. No bad tendencies at all. Just food for thought.

Eddie
Yep... trashed those batteries. I had some 4/5 Sub C 1300 mAh cells on hand and made up two 5 cell packs from them this morning and am charging them now to check. I've been using some of those cells in my DeWalt screw driver so think they are capable batteries. I'd ordered batteries for the screw driver and doubled the order so had them.

As to the balance, I'll keep that in mind and more especially if I can't leave the flight batteries on the engine box because then it would mean ballast weight would be needed.
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Old Jan 23, 2011, 12:48 PM
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Good to find that they are bad early. Just don't go to far back on the CG if you do move it back.

Eddie
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Old Jan 24, 2011, 12:00 PM
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Any news whether Dwain has recovered from his cold or Waylan from surgery?
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Old Jan 24, 2011, 05:28 PM
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Just to let you know, I'm working on a stand way off scale P-51, nitro powered. Hope to have it ready in a couple of weeks. (I'm just slow, o.k.)
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Old Jan 24, 2011, 05:49 PM
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I ran the engine up in the Yak this afternoon and didn't seem to get any EI issues so it's ready to maiden.

I also talked with Dwain for a few minutes... he's over the crud and anxious for a good fly day.
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Old Jan 26, 2011, 07:25 AM
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Went down to Newts yesterday had a good visit he's like myself ready to get out to the field and start flying.
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Old Jan 30, 2011, 09:39 AM
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Maiden flight report of Nitro 72" Yak

The Yak got her maiden yesterday.

The good;
  • It came home in one piece
  • The motor was reliable so no dead sticks
  • The motor had lots of power
  • Good advice from Eddie to reduce throws for initial flight. They were still too hot and reduced more for second flight which was comfortable.
  • After trimming, the plane flew relatively well

The bad;
  • Top end might have been too rich yet as the plane collected more gunk than normal for a gasser
  • The plane required a lot of up trim
  • Knife edge and vertical required pitch corrections
  • It does not taxi well in thick grass... too much drag at wheels and pants.
  • When starting the plane on the horse and setting on the ground, the pitch/roll changes incurred with doing so kills the engine.

It seems apparent that a trim issue exist. It required too much up trim. What I remember about the flight is;
  • No trim problems between a low and high speed pass so thrust line is good. Also, vertical climb didn't require much yaw adjustment so again right thrust is about right.
  • Inverted required only a fraction of down
  • Neither knife edge or vertical climb were pitch stable though I can't recall which corrections were needed.
  • In flight CG check produced no curl or tuck
  • Idle was set too low for landing
Because the wing and bolt on stab were both pegged, I didn't check them for incidence....I will as the plane certainly needs some dialing in.

Because the model went into a dive when attempting to trim, I asked Gene to assist and we kept cranking up it seemed forever. IIRC, I asked for two clicks of roll trim but took one of those back out so roll trim was very close.

Thanks to Eddie for the throw advice, which turned out to be very crucial advice. I'd set things up initially for a lot of throw but thought I was ok with 50% expo. Eddie had me cut the throws by 25% and they were still hot, especially the aileron. Changes were made prior to second flight with ailerons reduced to 50% throw and 60% expo and elevator to 60% throw and also 60% expo. The second flight felt about the way I like it. At the initial setting without Eddie's council... the plane with fighting the strong amount of down, would have been a handful for sure.

Thanks also to Gene for rescuing me with trimming. My first two attempts to let go of the stick long enough to get to the trim tabs saw the plane dive hard both times.

I will not be happy with the plane until it will taxi in some grass and offer pitch stability in knife edge and vertical climb. I'm in hopes that large enough wheels can be fitted for grass... if not the wheel pants will go and then I know that large enough wheels can be fitted.

If you are still reading... thanks for following the report.
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Last edited by AA5BY; Jan 30, 2011 at 09:48 AM.
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Old Jan 30, 2011, 10:53 PM
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Arlyn the yak did look great through i missed the second flight but maybe will get to see it again . it is a vary good looking plane.
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Old Jan 31, 2011, 08:08 AM
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Originally Posted by luker737 View Post
Arlyn the yak did look great through i missed the second flight but maybe will get to see it again . it is a vary good looking plane.
Thanks Mike... with a little more effort, it has the makings of being a good plane.

I will say as far as flight capability, the Akrobat II, the old Gerry Graham design (my yellow/black/white plane) is a smoother and more precise flier. The Akrobat II suffers no pitch issues on either knife edge or up lines and if one follows all the chatter about modern performance machines, there are a lot of battles to obtain those qualities.
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Old Feb 01, 2011, 07:23 PM
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Y'all got yer nickers on?
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Old Feb 02, 2011, 03:00 AM
NVS
Longview, Texas
Joined Dec 2007
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I am just guessing now, but I bet no one flew today. Dang it's cold !!!! Better days are coming, just not real soon.

Glad your maiden flight went well. The first one is always the most scary.

Stay warm and hope the weekend brings a few degrees so we can fly again.

Gene
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Old Feb 02, 2011, 07:03 AM
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Gene... you didn't fly yesterday?

My wind gauge froze up so I didn't get any recordings of how strong the gust were.... but no gauge was needed to know.... too strong. Strangely the anemometer (frozen yesterday) is working this morning though the direction is still frozen in place.

Worked on my tv again yesterday... the turn on circuit has been messing up for a long time. I'd gotten it working twice by resoldering components but the fix lasted about six weeks the first time and about half that the second time. The last time I only resoldered two components so think I've got the problem area zeroed in on, either a transistor or a zenier diode. I pulled the transistor yesterday and checked it and it produced good numbers. The diode basically checks but is a 28v zenier and my guess has wandered off specks and has the circuit out of balance. I'm betting the problem to be the diode but with $9 shipping and handling, I ordered all six components in the circuit (4 transistors and 2 diodes).

Also moved the CG back a bit on the Yak. The combination of up trim needed, tippiness on taxi and the pronounced down pitch on landing flare seem to indicate it needs to go back. I'd balanced it on the tube whereas the CG was called out 1/8 aft of the tube. Inverted only required a touch of down however, but we'll check out the change.

Ultimately I might adjust the horizontal stab but will get the CG locked first instead of messing with two things at once.
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Old Feb 02, 2011, 09:51 AM
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I have a really bad case of cabin fever! Wish the temps would go way up and the wind
go way down. Well, you know what they say about wishes.
Maybe by the weekend things will improve.
B.S.
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Old Feb 02, 2011, 11:22 AM
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texas
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Just a reminder .The Rains County RC club is having there swap meet & indoor free fly this weekend and it's free maybe you can find a treasure there.
It all starts at 10am 2/5/2011 at the high school 1759hwy 69 Emory TX.
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Old Feb 03, 2011, 02:15 AM
NVS
Longview, Texas
Joined Dec 2007
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Yeah, I went out yesterday and flew all by myself. I kept waiting for some of the club members to show up, but no good. Just because it was blowing 40 mph and it was 10 degrees, I figured at least some of the regulars would show....but no...I had to fly alone. Had a great time all by myself. I did cut off three fingers due to frost bite, but had a great time indeed. Then it got colder and......well you all can call me Lefty now !!!. It's hard typing with one hand and three fingers but what the hell, I had a good time time flying. See all you wimps when the weather gets warmer.....

Gino
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