RE: Extreme Flight RC Yak 54 - 74 inch!

RE: Extreme Flight RC Yak 54 - 74 inch!
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RE: ... - 2/6/2008 7:10:17 PM

Christoph P.

Posts: 21
Joined: 11/3/2005
From: Heidelberg, GERMANY
Status: offline

Hi there,

Have you guys also got that heavy vibration/flutter on the elevator? Part of this seems to come from engine vibration and resonance (though I run an OS FS200, which is quite smooth), but the propwash shakes the elevator quite heavily on full throttle, already on the ground. As I have to remove the elevator halves for transport, I can't simply put up some carbon rods to the fuselage to stabilize it.

I wonder if I need to do anything about this - what about those who run a gasser with even more power and vibration? Has anyone ever experienced any problems or even a loose or broken elevator due to vibration and flutter?

Thanks for your advice,

Christoph

(in reply to FLYMIKE)

Post #: 2026

RE: ... - 2/6/2008 7:54:01 PM

FLYMIKE

Posts: 570
Joined: 6/20/2006
From: WEST VALLEY, UT, USA
Status: offline

I have vibs but nothing to the elevaters...some in my wings which transfers to my landing gear in the air......The longer you mount your enjine out.. the more vibs...check prop balance and I have put foam around my firewall that reduced 50% of the vibs....Its a very light weight filter #5001 Briges and Straton (green) air filter from Home depot....

(in reply to Christoph P.)

Post #: 2027

RE: ... - 2/6/2008 8:53:52 PM

Michaelh

Posts: 386
Joined: 6/19/2005
From: Hampton, VA, USA
Status: offline

Oh No Mike , You know its always the plane that flies good !

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Post #: 2028

RE: ... - 2/6/2008 8:59:27 PM

FLYMIKE

Posts: 570
Joined: 6/20/2006
From: WEST VALLEY, UT, USA
Status: offline

Your only as good as the plane and settup..

LOL

< Message edited by FLYMIKE -- 2/6/2008 9:00:10 PM >

(in reply to Michaelh)

Post #: 2029

RE: ... - 2/6/2008 9:03:36 PM

FLYMIKE

Posts: 570
Joined: 6/20/2006
From: WEST VALLEY, UT, USA
Status: offline

One more thing about vibration...it decreased when I took the right thrust out of the motor..alot

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Post #: 2030

RE: ... - 2/6/2008 9:05:32 PM

FLYMIKE

Posts: 570
Joined: 6/20/2006
From: WEST VALLEY, UT, USA
Status: offline

quote:

ORIGINAL: Christoph P.

Hi there,

Have you guys also got that heavy vibration/flutter on the elevator? Part of this seems to come from engine vibration and resonance (though I run an OS FS200, which is quite smooth), but the propwash shakes the elevator quite heavily on full throttle, already on the ground. As I have to remove the elevator halves for transport, I can't simply put up some carbon rods to the fuselage to stabilize it.

I wonder if I need to do anything about this - what about those who run a gasser with even more power and vibration? Has anyone ever experienced any problems or even a loose or broken elevator due to vibration and flutter?

Thanks for your advice,

Christoph

And if you have actual flutter....then your linkages are not settup right...do you have pics?

(in reply to Christoph P.)

Post #: 2031

RE: ... - 2/7/2008 8:08:21 AM

Christoph P.

Posts: 21
Joined: 11/3/2005
From: Heidelberg, GERMANY
Status: offline

No, it's not the linkages. These do not have any play, and the Servos are strong enough (Hitec 6975HB). The problem is that the WHOLE elevator is shaking up and down, including the stabilizer. Not sure what to do here, both sides are affected...

Christoph

(in reply to FLYMIKE)

Post #: 2032

RE: ... - 2/7/2008 11:07:48 AM

xtraflyr

Posts: 1618
Joined: 3/10/2002
From: Chester, NJ, USA
Status: offline

quote:

ORIGINAL: Christoph P.

No, it's not the linkages. These do not have any play, and the Servos are strong enough (Hitec 6975HB). The problem is that the WHOLE elevator is shaking up and down, including the stabilizer. Not sure what to do here, both sides are affected...

Christoph

Christoph,
I just remembered that I had the same problem,but it didnt shake that as bad as yours sounds.. My CF stab tube became loose in the socket. I just wrapped a single layer of Ultracote around it and the shaking went away.. Give that a try..

Cya,
Frank

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Post #: 2033

RE: ... - 2/7/2008 8:04:20 PM

FLYMIKE

Posts: 570
Joined: 6/20/2006
From: WEST VALLEY, UT, USA
Status: offline

Also check the tuning of your motor...to rich will cause any motor to vibrate to much....if you have a tac...just set it to the recomended low end....make sure the mounts are not loose....I dont know those servos and if they are carbonite gear, they will strip a gear eventually.....hope you figure this out...

(in reply to xtraflyr)

Post #: 2034

RE: ... - 2/7/2008 11:33:42 PM

Richard D Bahmann aka/Wrongway

Posts: 2051
Joined: 1/7/2004
From: Ormond Beach, FL, USA
Status: offline

quote:

ORIGINAL: Christoph P.

No, it's not the linkages. These do not have any play, and the Servos are strong enough (Hitec 6975HB). The problem is that the WHOLE elevator is shaking up and down, including the stabilizer. Not sure what to do here, both sides are affected...

Christoph

How tight is the tail tube when the stabs are off it? After a bunch of flight time on my 88 inch EF I found that the stabs would shake at idle. The tube had gotton loose in the receiver tube. I carefully drizzled some thin ca in there and wiped it with my finger to spread it around (inside the receiver)in the back of the fuse. Don't zip kick it but as soon as it is dry fit it then take it apart until the CA has set good then re assemble . I had to use a little CA in the stab receivers too. About 40 flights since and all is tight.
We all balance our props like we should but if you have a spare prop to put on it to compare it might help you decide where is the problem.
Let us know what you find.

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Post #: 2035

RE: ... - 2/10/2008 5:06:55 AM

GregT882762

Posts: 180
Joined: 9/26/2006
From: union city, TN, USA
Status: offline

Question? Have a new OS 160 with factory muffler on the way just curious if that muffler would work or do i have to buy the pitts? I would have bought just motor and then pitts,but found a new one on rcgroups NIB w muffler for 225 shipped couldnt pass that up?

(in reply to Richard D Bahmann aka/Wrongway)

Post #: 2036

RE: ... - 2/10/2008 9:14:51 PM

Christoph P.

Posts: 21
Joined: 11/3/2005
From: Heidelberg, GERMANY
Status: offline

The tail tube is tight as well. I guess what is happening here is that the whole rear end of the fuselage can be slightly rotated along its axis which may cause the stabs to move up and down a bit. I'll try another propeller too, but the engine is running quite smooth.

I now had a totally different problem: when flying on the weekend at some altitude I suddenly saw parts of the plane coming off... my initial thought was that one elevator half broke off, and I'd loose control any second, but it was in fact only the canopy! Landing was no problem, but my canopy is DEAD. Also, when coming loose, it hit one elevator stab, which is damaged now and I've got scratches over one wing.

As my canopy was secured with two carbon rods in the front in addition to the normal wooden block and as the rear latch is still OK, I gather air must have come under it somehow, causing it to bend outward and burst. In fact, the canopy came down in several pieces (which may also have been caused by the collision with the elevator), but I think it was already broken as it flew off.

Really annoying... and I got a stab to repair - does anyone know where to get the original yellow covering from?

Cheers,

Christoph

(in reply to GregT882762)

Post #: 2037

RE: Extr... - 2/10/2008 9:32:51 PM

Christoph P.

Posts: 21
Joined: 11/3/2005
From: Heidelberg, GERMANY
Status: offline

quote:

ORIGINAL: xtraflyr

OK guys here ya go,check them out.. It looks like whats left of it the glue joint held and the framework busted. But there's a big chunk of canopy missing..
The last thing I was doin was just an outside loop,came out of it flew a little bit more then it flew off..
Cya, Frank

THIS (page 60, post 1479) is exactly how my canopy looks like! Big crack just before the beginning of the "windscreen", the glass part of the canopy is intact. This seems to be a vulnerable part. No changes to the fuselage, no air coming in anywhere. Also, unlike xtraflyr I was in level flight as it happened.

New canopy will be reinforced in that area. Also, I intend to put in strong magnets to hold it down.

Cheers,

Christoph

(in reply to xtraflyr)

Post #: 2038

RE: Extr... - 2/11/2008 1:46:31 AM

xtraflyr

Posts: 1618
Joined: 3/10/2002
From: Chester, NJ, USA
Status: offline

quote:

ORIGINAL: Christoph P.

quote:

ORIGINAL: xtraflyr

OK guys here ya go,check them out.. It looks like whats left of it the glue joint held and the framework busted. But there's a big chunk of canopy missing..
The last thing I was doin was just an outside loop,came out of it flew a little bit more then it flew off..
Cya, Frank

THIS (page 60, post 1479) is exactly how my canopy looks like! Big crack just before the beginning of the "windscreen", the glass part of the canopy is intact. This seems to be a vulnerable part. No changes to the fuselage, no air coming in anywhere. Also, unlike xtraflyr I was in level flight as it happened.

New canopy will be reinforced in that area. Also, I intend to put in strong magnets to hold it down.

Cheers,

Christoph

Yup I had the same problem. I made sure I had lots of extra glue where the canopy meets the wood frame. I also added a couple pieces of velcro to the canopy. No more problems since..

Ok guys another question..
Im goin to put the Brillelli 46gt in the 74" and take out the OS 160. Since I havent been paying attension. What size Fuel Tank you using and what size prop seems to work for the combination,wheres the batteries and rx located?

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