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All Forums >> RC Airplanes >> Giant Scale Aircraft - 3D & Aerobatic >> Aero-Works Support >> 50cc YAK rolls out in loop
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50cc YAK rolls out in loop - 9/9/2007 6:17:40 AM   
madman75



Posts: 110
Joined: 9/28/2006
From: Newport, OH, USA
Status: offline 		I have only flown mine about a dozen times. I'm still trying to get the feel for it. Anyway, I tried to do a tight loop and the plane rolled to the left at the top of the loop. The elevator is at the low rate setting suggested in the manual. I then tried to do a tight inside loop and the same thing happened. The plane flies straight with only a couple of clicks up elevator and a couple of clicks of left aileron to trim it out. Is this roll out typical or is there something I can do to correct this?
Thanks
       Post #: 1

RE: 50cc YAK rolls out in loop - 9/9/2007 3:22:04 PM   
krayzc-RCU



Posts: 5928
Joined: 3/26/2002
From: Kannapolis, NC, USA
Status: online 		what is the low rate throw in degrees for the elevator?

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RE: 50cc YAK rolls out in loop - 9/9/2007 3:44:49 PM   
bubbagates



Posts: 8162
Joined: 5/30/2004
From: Elizabethtown, PA, USA
Status: offline 		This could be any of the following

uneven elevator throws (check with balsa sticks glued to clothes pins and clipped to each elevator and have them meet back behind the rudder. Throw guage work but it's really hard to see any difference
Lateral balance
Engine thrust
CG is not correct
Incidence is off on any one surface
Too much throw for the speed

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RE: 50cc YAK rolls out in loop - 9/10/2007 3:54:43 AM   
madman75



Posts: 110
Joined: 9/28/2006
From: Newport, OH, USA
Status: offline 		The elevator is set at 12 deg. up and 16 deg down for low rates per the manual. The CG is set at 4 1/4" slightly nose heavy per the manual. I do have a 25 oz tank that is ahead of the wing tube so this would make the plane more nose heavy when fueled. No way to really change any incidence since it's all pre-built. Engine thrust is all set by the firewall. I didn't change anything there. I just bolted a DA-50 after I drilled the holes. It does have right thrust in it. I haven't checked lateral balance. How's a good way to check it? I'll check the elevators for even throw. I set the elevators up with a throw gauge. I was flying less than half throttle when I tried the loops.
Paul

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RE: 50cc YAK rolls out in loop - 9/10/2007 4:53:52 AM   
krayzc-RCU



Posts: 5928
Joined: 3/26/2002
From: Kannapolis, NC, USA
Status: online 		try full throttle on the loops until you get to about 2/3 into then reduce throttle to see if it still does not act correct:


http://www.mini-iac.com/Portals/57ad7180-c5e7-49f5-b282-c6475cdb7ee7/PGoldsmith%20on%20trimming.pdf

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RE: 50cc YAK rolls out in loop - 9/10/2007 12:49:56 PM   
bubbagates



Posts: 8162
Joined: 5/30/2004
From: Elizabethtown, PA, USA
Status: offline 		Paul,

It really does sound like elevator issues. try the stick method I explained above. The elevators my be alright at full throw both low and high, but how about inbetween. That is very hard to do with a guage unless great care is taken when moving the guage between the elevators. The still method allows you to see it quickly and easily.

To check this out you need to do this in a specific order. I had this very plane and though all the thrust and incidences are set they can be off. Mine needed more right thrust and some up thrust. My left wing was also heavy.

In this order and while flying with someone taking notes, it's important that you only do one at a time as one effects the other and only after you verify the elevators are tracking correctly.

Ok now lets look at the CG.

Take the plane into a 45 degree climb. Once in the climb roll inverted and hold the 45 degree line. Once the line is established let go of the sticks and see what the plane does. If it stays right there your CG is neutral and the plane will be at it's best for both 3D and IMAC. if the nose climbs you are tail heavy and if it slowly drops then you are nose heavy. I personally like mine to be slightly nose heavy. My planes take around 7 to 10 seconds to come level.

Fly into the wind, if any, and pull straight up right in front of you with the side of the plane facing you. Once you are going straight up stop making corrections and let it climb. If you see it pulling towrds the canopy you have too much upthrust, If it goes to the gear you have too much downthrust. You can confirm this by flying level and chopping the throttle quickly from say 80% power and watching the nose. If it comes up then you have too much downthust, if it comes down then you have too much upthrust.

Now once you have that sorted out, go veritcal again only this time have the top facing you, again get it flying hands off and wait to see if the plane starts leaning left or right. It it starts leaning left you need right thrust, if it leans right you need left thrust.

Ok lets look at lateral balance. As I mentioned before you can do it during inverted flight or pull a huge loop and see which wing drops. Another way is have two people. Pick the plane up by the spinner with the engine between it's compression stroke and the other person with a finger under the fuselage right at the back, just before the rudder. Get the wings level and let the wings go and see which one drops consistently. If it does not drop the same one consistently then niehter is heavy or you are not holding the wings level before letting them go each time. If one wing drops consistently, then add weight to the opposite wing.

The above stuff can take up to 40 flights to get it right but when you are done, you will have one very predictable plane that will fly just how you want it.


< Message edited by bubbagates -- 9/10/2007 12:53:48 PM >

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Normal is not something to aspire to, it's something to get away from

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RE: 50cc YAK rolls out in loop - 9/25/2007 11:50:20 PM   
madman75



Posts: 110
Joined: 9/28/2006
From: Newport, OH, USA
Status: offline 		The only thing I have checked is the elevators. I found one elevator half was about 6 degrees off from the other. I haven't flown it yet. I've been working to many days. I try some of the other things suggested.

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RE: 50cc YAK rolls out in loop - 10/3/2007 2:49:21 AM   
madman75



Posts: 110
Joined: 9/28/2006
From: Newport, OH, USA
Status: offline 		I checked the lateral balance and found the left wing is about 3/4 oz heavier than the right. Should I add 3/4 oz to the right wing?

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RE: 50cc YAK rolls out in loop - 10/3/2007 3:21:09 AM   
reyn3545



Posts: 964
Joined: 7/1/2006
From: Alpharetta, GA, USA
Status: offline 		Sounds like you just weighed the wings.. do a serch for lateral balance, there are several articles on how to check and adjust.. in a nutshell, you'll need to suspend the plane from the tail and the prop, and see which wing dips... add weight to the "light" wing (out on the tip) until the plane will hang with the wings level. Once you determine which wingtip to add the weight to, just cut some of the covering from the bottom side of the tip, glue the weight in, then re-cover the hole... good as new!

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       Post #: 9

RE: 50cc YAK rolls out in loop - 5/28/2008 8:22:58 AM   
jerrysu29



Posts: 261
Joined: 11/23/2002
From: Rapd City, SD, USA
Status: offline 		Bubbugates is on the right track about uneven travel rates of the two elevator halfs. I have fixed this problem on 3 AeroWorks, and 4 hangar planes in my area.I have found with out some way to match centers, and end points on both servos you are going to have this problem. I use two throw meters to check for this. Most of the guys that I helped thought they were haveing some of the same problems. IE CG off, incedence on one or more surfaces off, but on all 7 of these planes I found the two elevator servo arms off at center, not exactly perpendicular to each other and found they had tried to use subtrim to fix this, by using subtim what you find is know they are perpendicular with each other, but your end points, will not be the same. Thus causing the plane to, roll out of a loop, or barrel roll,one direction or the other. I have two AeroWorks YAK's 50cc % 75cc also Hangar 9 Sukhoi's all but one have the Hitec servo's which I have programed with the Hitec programmed one Sukhoi has JR 8611's which I'am using the JR match boxes on to stay away from these type of problems SO FOR WHAT IT WORTH YOU HAVE MY 2 CENTS

Jerrysu29 Call Sign Wildman

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RE: 50cc YAK rolls out in loop - 5/30/2008 12:19:14 AM   
gregman50


 

Posts: 188
Joined: 11/24/2005
From: Mt. Holly, NC, USA
Status: offline 		I have this same plane with a DA-50, I have Hitec 5985's on the elevators, the CG is at 4 1/2 inches, I moved the batteries onto the canister tunnel on a small tray that I made to get the CG to balance it there. The plane still is just a fine line nose heavy, I made sure that I had the same amount of through in both elevator halfs and that they were netural without any input, the plane flies all manaverurs almost perfect, I added very little mixing for KE, only about 1%. Mine will not do what is described here when doing a tight loop, could be as simple as making sure the elevator halfs have exactly the same amount of throw. I just maidened my 75cc/ZDZ Super 80 last week and the plane is simply put "amazing" awesome combo, fllies like a trainer! My next purchase will be the 100cc Yak or maybe the 100cc Extra 260, hard decision!!

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       Post #: 11

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