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Flap up adjustments.

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psm(at)att.net
Guest

Posted: Sun Jun 28, 2009 8:04 am Post subject: Flap up adjustments.

Hi Sabrina,



I thought the flap stop issue was about the flap itself moving around 

when in the up position.  It sounds like you think it has something 

to do with the air seal when the flaps are up.  Is that the 

case?  Why do you feel that way?  Or, is your tape on the flap gap a 

matter of holding the flap firmly in place?



I found I wanted a "Press fit" between the flap and the wing rear 

channel structure when the motor is stopped in the up 

direction.  This way the flap is very firmly held in place during 

normal flight activities.  Also, take note of the fact I found this 

very difficult to accomplish.  The adjustment is all done while 

"Standing on your head" after mounting the wings to connect the two 

flap torque tubes to the control arm tube.  My approach was to add 

another "Inner" tube bolted to one of the torque tubes, then connect 

the two outer tubes together making the flaps move exactly together, 

and finally using the center control arm tube to adjust the final 

position along with the motor stop switches.

Paul

XL grounded

At 07:43 AM 6/28/2009, you wrote:



 	  Quote: 	
		  If I had a shiny airplane and I flew over a power plant and 

experienced what I thought was flutter, I would land, put a long 

piece of duct tape over the top of/sealing each flap gap, pull the 

fuse on the flaps and then go solo over the same power plant 

again.    The flap stop gap nylo does little if the flap limits are 

set improperly.

sabrina

Joined: 15 Jun 2009
Posts: 170

Posted: Sun Jun 28, 2009 12:05 pm Post subject: Re: Flap up adjustments.

Do Not Archive

Last edited by sabrina on Fri Jul 03, 2009 3:12 am; edited 1 time in total

Juan Vega Jr

Joined: 13 Jan 2009
Posts: 157

Posted: Sun Jun 28, 2009 5:23 pm Post subject: Flap up adjustments.

Sabrina,

I complete;y dissagree with your assessment.  Most stops on most aircraft are actually an adjustable screw/ bolt.



The flap stop needs to be solid, and the flap motor needs top push the flap past the point of where it is touching the stop to about 2 mm past.  htis locks the flap in place.  any movement makes for a half _ss install and rushed.  Using duct tape for the phase I is just bad advice.  DO it right the first time,  built it right the first time.  



jUAN vEGA

--

sabrina

Joined: 15 Jun 2009
Posts: 170

Posted: Sun Jun 28, 2009 8:14 pm Post subject: Re: Flap up adjustments.

Do Not Archive

Last edited by sabrina on Fri Jul 03, 2009 3:12 am; edited 1 time in total

psm(at)att.net
Guest

Posted: Sun Jun 28, 2009 8:42 pm Post subject: Flap up adjustments.

Hi Sabrina,



I agree with everything you said about the flaps and phase 1 

testing.  As I remember reading in the FAA test Advisory Circular, 

you should not use flaps on your first flight.  That is similar to 

not cycling the landing gear on your first flight if you have 

retracts.   It is all about doing as little as possible to make the 

first flight as likely as possible to be successful and without problems.



My take on the bigger issue with Zodiac XL flaps is the question of 

how they might contribute to in-flight problems.  If they are not 

firmly held in place during cruise flight then they could definitely 

make life very interesting.  Any movement and particularly any 

repeated and possibly diverging oscillation would certainly cause 

unwanted excitement.  They have a shape and location similar to 

ailerons, but you really don't want them to act at all like ailerons.



I agree with Juan's comments about forcing the flaps against the 

stops with the flap motor.  That should keep them out of any 

interesting events in normal flight.  It would be even better if you 

could get them to lock in place.  It seems to be a different thing 

entirely when the flaps are deployed.  Then the more interesting 

question might be whether they present an even load or lift to the 

airframe without introducing a roll component to make life more interesting.



Have fun,



Paul

XL grounded

At 09:14 PM 6/28/2009, you wrote:

 	  Quote: 	
		  It is clear that the German test results show that a improperly 

stopped flap gap is bad news.   If one is conducting Vne Phase 1 

testing, duct tape over the flap gap sounds like a good idea to me, 

just in case the builder did not get it correct.  Not during all of 

Phase 1, just for critical periods during Phase 1.



I would even say so for the maiden flight...  just one less thing to go wrong.

sabrina

Joined: 15 Jun 2009
Posts: 170

Posted: Sun Jun 28, 2009 9:15 pm Post subject: Re: Flap up adjustments.

Do Not Archive

Last edited by sabrina on Fri Jul 03, 2009 3:13 am; edited 1 time in total

Juan Vega Jr

Joined: 13 Jan 2009
Posts: 157

Posted: Mon Jun 29, 2009 6:53 am Post subject: Flap up adjustments.

that I agree with. My point is people are building the flaps with too much play, and they think that is fine. They need to do it right the first time, or should be redone.



--

zenithlist(at)yahoo.com
Guest

Posted: Mon Jun 29, 2009 7:43 am Post subject: Flap up adjustments.

Sabrina,

  

 Do you have pictures or drawings of your flap stops which do not twist flaps?  I like to take a look at them.



 

   From: Sabrina <chicago2paris(at)msn.com>

To: zenith-list(at)matronics.com

Sent: Monday, June 29, 2009 12:15:22 AM

Subject: Re: Flap up adjustments.



--> Zenith-List message posted by: "Sabrina" <chicago2paris(at)msn.com (chicago2paris(at)msn.com)>



The solid stop XL flaps I have seen seem to have a smaller gap inboard than outboard.  This appears to be from the flap motor, which is connected to the inboard portion of the flap, twisting the flap the 2mm Juan talks about.  This puts a slight washout on the inboard portion of the flap.



In flight, air flow is fighting the solid stop XL flap due to this washout.



My flap stop does not load/twist the flap,  it loads the spar.  In flight, my flap stop is not being unloaded by air flow.





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=250550#250550





          [quote][b]

sabrina

Joined: 15 Jun 2009
Posts: 170

Posted: Mon Jun 29, 2009 8:07 am Post subject: Re: Flap up adjustments.

Do Not Archive

Last edited by sabrina on Fri Jul 03, 2009 3:13 am; edited 1 time in total

Juan Vega Jr

Joined: 13 Jan 2009
Posts: 157

Posted: Mon Jun 29, 2009 9:11 am Post subject: Flap up adjustments.

Good idea Sabrina, however if the flap motor puls the flap 2 mm past the point where the stop arrests the outboard edge,  the total twist on the flap is negligable,  max .0001 of one degree.  so at the speeds the 601 fly,  the negative incidence is moot.  good train of thought though.  check the geomtry by figuring the triangle angle measurements. 

Cheers,

Juan



--

sabrina

Joined: 15 Jun 2009
Posts: 170

Posted: Mon Jun 29, 2009 9:53 am Post subject: Re: Flap up adjustments.

Do Not Archive

Last edited by sabrina on Fri Jul 03, 2009 3:14 am; edited 1 time in total

Juan Vega Jr

Joined: 13 Jan 2009
Posts: 157

Posted: Mon Jun 29, 2009 10:52 am Post subject: Flap up adjustments.

no proplem,  so we disagree and  thats cool.  It sperfectly OK to overplay something in you mind such as the trwist,  anything to make you feel comfortable enough to feel like youve built a good aircraft works.



Juan



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Juan Vega Jr

Joined: 13 Jan 2009
Posts: 157

Posted: Mon Jun 29, 2009 10:52 am Post subject: Flap up adjustments.

Its so hot here in Florida these days,  that fresh road kill,  is good to eat since it is freshly cooked off the avement.



--

sabrina

Joined: 15 Jun 2009
Posts: 170

Posted: Mon Jun 29, 2009 11:16 am Post subject: Re: Flap up adjustments.

Do Not Archive

Last edited by sabrina on Fri Jul 03, 2009 3:14 am; edited 1 time in total

chris Sinfield

Joined: 28 Nov 2006
Posts: 270
Location: Sydney Australia

Posted: Mon Jun 29, 2009 12:47 pm Post subject: Re: Flap up adjustments.

Hi all

If I have up 2 flap stops one at each end of the flap, would that not stop the flap twist when up??

Chrisj

psm(at)att.net
Guest

Posted: Mon Jun 29, 2009 1:04 pm Post subject: Flap up adjustments.

Hi Chris,



I'm afraid that would create one of those unintended consequences.



The flap structure is moved by a force applied to the innermost 

rib.  That means any tendency it has to twist under aerodynamic 

forces would allow the far end to break free from the stop.  My 

notion of the twisting issue is the motor forces the structure to 

twist as much as it can before stopping upward movement.  This holds 

the whole structure firmly in place.



I don't really know how important this amount of movement is.  I 

suppose it depends on how stiff the flap is in the first place.  With 

its triangular cross section I doubt it would twist much under any conditions.



Paul

XL grounded

At 01:47 PM 6/29/2009, you wrote:



 	  Quote: 	
		  Hi all

If I have up 2 flap stops one at each end of the flap, would that 

not stop the flap twist when up??

Chrisj

sabrina

Joined: 15 Jun 2009
Posts: 170

Posted: Mon Jun 29, 2009 1:37 pm Post subject: Re: Flap up adjustments.

Do Not Archive

Last edited by sabrina on Fri Jul 03, 2009 3:15 am; edited 1 time in total

Juan Vega Jr

Joined: 13 Jan 2009
Posts: 157

Posted: Mon Jun 29, 2009 2:09 pm Post subject: Flap up adjustments.

sounds good,  good job.



Juan



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