mstenzler

Hi everyone-

I'm just about ready for the maiden flight on my yak with a Sato 125 on it but i have a couple of questions:

first- on the pull pull system for the rudder the little metal holders that you loop the cable wire through, do these need to be crimpped to keep them from sliding or did I loop them incorrectly? I can't seem to get the cables tight enough and when i do they just loosen up when i move the rudder several times. any help here is much appreciated. the instructions do not say to crimp these but i have found the instruction are not that great anyway.

Second- the throw for the aileron and elevator seem to be pretty aggressive even on low rates when set according to the directions. I have only been flying for about a year but this is my fourth plane, avistar, ultra stick (40 size) and P51 (60 size) and now the yak. i was just wondering if i should reduce the amount of throw for the first flight or do you guys think the settings per directions are ok? i have put about 75% expo in but don't want to loose her on the first flight.

Any suggestion?

YogoBlue

My Feedback: (17)

First. Yes double loop them.. then crimp them up good.
Set your rates as low as you can for low rates. Expo in this plane is a must.. 75 might be a bit agressive. On a specktum system I run about 45 or so. Watch for snaps on the elevator at high rates.

Setup well, this plane is a peach to fly. If you flew p51 you will have no problem as it will fly better.
Good luck and let us know.

WATCH THE CG and put it at 5.5inches back from leading edge near fuse!

mstenzler

Thanks Yogo,

Ok i will change my expo back some and reduce the throws and crip those little metal guys..

i do have the CG at 5.5 per this thread.... ok, keeping my fingers crossed and hope to give her a try this weekend, maybe New Years as the weather is supposed to be nice with not much wind..

YogoBlue

My Feedback: (17)

You will like this plane I am sure of it. When your ready for fun go high rates on aielron for some fun, but wait till your used to the plane.

Also remember these planes do have a snap tendancy if you dig into the elevator too much.

rcfunflyer

My Feedback: (72)

How big an air exit hole is required in the cowl for cooling? So far I only have the hole cut for the engine head and muffler.

CAT POwer

My Feedback: (61)

Hi, what are you guys using for down/right trust angle for a 20/26 gas engine.
Thanks Manfred

CAT POwer

My Feedback: (61)

Nobody else building one ?
Manfred

olflyr

I have had my Seagull Yak for just about a year and a half now. I installed a MVVS 26 gas engine in it and after a few flights I named it the "Flying Brick". After about 20 flights, none of them enjoyable, I decided to change the engine to an OS 1.20AX. What a difference, now it is one of my favorite planes and will do any manoeuver except a knife edge spin with ease. I balanced the plane as per the manual at 8cm back at the wing tip and I must admit that it is tricky on landing. Hate to move the CofG forward as it is a dream in the air. On my first flight the axle and wheel fell out of the nut that holds it on the landing gear. Luckily I was able to ditch it in some tall grass and suffered no damage. New axles from Great Planes and CF gear from Graph Tech and it has become a great performer at a reasonable price.

karolh

A Zenoah G20 would have been the answer in going to gas.

Karol

CAT POwer

My Feedback: (61)

HI, I'm going with a CRRC 26 that is lighter than the Z20. What trust angles did use ?
Manfred

karolh

More than likely all the thrust required is already built into the engine box.

Karol

CAT POwer

My Feedback: (61)

I will go with a strait bolt up and adjust as needed.
Manfred

tkg

My Feedback: (1)

Simple CG ckeck.
Trim for level flight. Pull to 45 deg upline, roll inverted, hands off.
If it climbs, your tail heavy, if it starts to dive, your nose heavy.
Adjust CG untill up line is LONG.
This way the cg is perfect for your plane, engine, style of flying
WME
I lost an axle after 25 flights.

CAT POwer

My Feedback: (61)

Axle's changed.....
Thanks
Manfred

karolh

TKG, how about a similiarly fairly easy check for the correct up/down thrust.

Karol

tkg

My Feedback: (1)

OK
Trim for level flight at full throttle.
At full speed chop the throttle to idle. Does the plane pop up or dive down??? If it pops up you have to much down thrust(or not enough up thrust). If it dives you have to much up thrust (or not enough down thrust).
BECAUSE if you have to much down thrust you have to trim the elevator up so the plane will fly level. When you suddenly remove the downward thrust and the plane is still at speed then the elevator trim makes it pop up.

karolh

Thanks.

Karol

venicerc

I have just built this plane and set the cg just behind the wing tube and the first flight it seemed very tail heavy but the cg is set nose heavy went straight up after take off have evoloution 26 with 18x6 xoar prop has plenty of power any ideas on the vertical take off and scary handling i didnt flt it I had veteran trainer fly it because of mods done to make everything work

karolh

With a very tail heavy and highly powered model, holding excessive back pressure during take off could result in a very steep takeoff. There has been a lot of discussion in this thread on CG location as it seems that there was some conflicting information regarding it's position in the instructions from the manufacturer.

Do some reading here and see what the people that have flown this particular model did in arriving at the correct CG setting, but as I recall the majority seem to find that a CG set at 5.5" back from the leading edge next to the fuse made for a nice flying model.

Karol

venicerc

thanks for the info i think i need more down thrust because cg at 5.5 shows to be nose heavy as it was on the first flight but i have no idea how much to put in

venicerc

here is a link to the maiden flight any one got any ideas

http://www.youtube.com/watch?v=uzIJPMe5uGQ

karolh

Wether your model is nose heavy or tail heavy, check posts 735 and 737 from TGK in this thread for two fairly easy ways to check your CG and up/down thrust. Adjust as necessary until you are satisfied with how the model behaves.

Judging from the video, the flight seemed quite normal except for the beginning when the model appeared to fly a bit nose high and maybe needed some trimming.

Karol

thomasbrad44

My Feedback: (4)

Do you guys think a Zenoah G-20 would be a good fit for this plane?

Thanks
Tommy

karolh

YES.

Karol

firstdegree

Anybody got any thoughts on this? There's a couple of Yaks at our club and both seem to need up elevator trim to fly straight and level.