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Hmmmmmmmmm That ain't right.

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cjpilot710(at)aol.com
Guest

Posted: Sat Nov 25, 2006 3:46 pm Post subject: Hmmmmmmmmm That ain't right.

This evening I took my CJ up for one of my "Clear the soul" acro flight at  sunset.  Just to spend thirty minutes with just me and the CJ having a love  feast with the western sky ablaze in coral gold.

  

 :05 minutes into my little routines, I started noticing the old girl  just wasn't performing on her up lines and I started hearing a thump noise now  and than.  Since I had left the canopy cover in the baggage compartment, I  though that it was since I would hear it as I would release back pressure  on some of the over the top maneuvers.  Than on the last maneuver I heard a  very healthy 'clunk'  (Hmmmmmmmmm that ain't right). I decided to stop  right there and set myself for a landing on our airpark right under me.  I  looked down at my system air pressure gage and she was reading 25 atoms.   Hmmmmmmmm that ain't right either.  I was either losing though a leak or my  compressor has crapped out.  

  

 The "thump" and "clunk" were my landing gear.  On my CJ there are  NO up locks (yes, it came that way) so that if I loose system  pressure (below 20 atoms) the gear starts to fall "automatically".  My  emergency gear extension procedures are a little different than most  CJ-6s.  I simply put the gear down, wait for them to fall, than open the  emergency valve to lock them over center.  Yes - I have to keep  my gear handle in the up position all the time and no - it will not wear  out anything.  Been doing it that way for over 1,500 hours and 11  years now.

  

 What was happening here was, I was loosing pressure to the point when I  pulled any G's the gear would start to extend, and than when I released the back  pressure on the stick and dropped the G load, the gear would pop back up ( thump  & clunk ) in the well.  

  

 So tomorrow afternoon I'll start to trouble shoot what is wrong.  I  hope its not the compressor But since I didn't hear any air leaks on the ground,  I already have sneaky suspicion it may be.  I may luck out. ( I can  hear Doug Sapp panting already)    

  

 Stay tuned Oh fellow Aviators.

  

 Jim "Pappy" Goolsby

  

  

  [quote][b]

wlannon(at)cablerocket.co
Guest

Posted: Sat Nov 25, 2006 6:43 pm Post subject: Hmmmmmmmmm That ain't right.

Jim;

  

 There are a number of early CJ's that had the uplocks removed in service.  Even with 40 Atms in the air system pulling (and releasing) 3 or 4 G's should  have the gear up lights winking at you - long before you get the thump and  clunk. Assuming of course that the switches are correctly adjusted.

  

 Cheers;

 Walt

 [quote]   ---

cjpilot710(at)aol.com
Guest

Posted: Sat Nov 25, 2006 10:27 pm Post subject: Hmmmmmmmmm That ain't right.

In a message dated 11/25/2006 9:45:47 P.M. Eastern Standard Time,  wlannon(at)cablerocket.com writes:

  

 You may be right.  I'm too busy watching out side, I'm  sure to  miss seeing that.  Next time I'll bring my eyes for quick look.

  

 Jim

  

 [quote]   Jim;

    

   There are a number of early CJ's that had the uplocks removed in service.    Even with 40 Atms in the air system pulling (and releasing) 3 or 4 G's should    have the gear up lights winking at you - long before you get the thump and    clunk. Assuming of course that the switches are correctly adjusted.

    

   Cheers;

   Walt

   [quote]     ---

mj(at)yakuk.com
Guest

Posted: Sun Nov 26, 2006 1:48 am Post subject: Hmmmmmmmmm That ain't right.

It astounds me that for 11 years you have known about this problem and done

nothing about it !! Just because you took delivery of the a/c with parts

missing does that mean its OK? 



 



At 4 G you are on the gear limit speed. The P51 would tear its wing off if

the gear deployed at maneuvering speed I am told (is that true?) 



 



Just goes to show how non airworthy a/c can fly in the USA and hide behind

"its my freedom to do so - or right"       



 



BTW, there is an SB on YAK 11 that said keep the gear lever in up position

in flight. I deduce that other CJ owners may not be doing this. The reason

being is to prevent damage to the U/C. The same reason exists today on all

YAK types. 



 



B,BTW it was Dan McCue in 2004 and apparently got 9G on the clock. Can

anyone asses from the video what his airspeed was to be sure it was 9G? Is

the 9G stall at approx 240 kts on a YAK 3?

rvfltd(at)televar.com
Guest

Posted: Sun Nov 26, 2006 12:02 pm Post subject: Hmmmmmmmmm That ain't right.

Pappy,

 Check your gear up hoses.  Years back I  had the same symptoms in the mini yak and found the "up" hoses were leaking  badly.  I suspect that your hoses (in your CJ) are nearly as old as  you are, so you might check there first.

  

 And by the way, I DON'T pant........might  salivate a bit, or even drool in an extreme circumstance, but I do not  pant!! ;O)

  

 Best to all from Omak.

 

Always Yakin,

Doug Sapp  [quote]   --

cjpilot710(at)aol.com
Guest

Posted: Sun Nov 26, 2006 4:48 pm Post subject: Hmmmmmmmmm That ain't right.

In a message dated 11/26/2006 4:50:46 A.M. Eastern Standard Time,  mj(at)yakuk.com writes:

  

 Mark,

  	  Quote: 	
		  -->    Yak-List message posted by: "Mark Jefferies YAK UK"    <mj(at)yakuk.com>



It astounds me that for 11 years you have known    about this problem and done

nothing about it !! Just because you took    delivery of the a/c with parts

missing does that mean its  OK? 	
 First of all that is the way it  came to the USA. The Chinese said it was "airworthy" when I got it.   And I've seem one manual schematics that shows NO up locks.  For me  this NOT a problem.

 



At 4 G you are on the gear limit speed. The P51 would tear its wing  off if

the gear deployed at maneuvering speed I am told (is that true?)  

 

 

 I enter my loops at 140 kts IAS (engine is an  M-14P and just me).  I pull 2.5 to 3 Gs.  I don't need any more than  that.  It is the way I fly my loops.  I am not interested in a perfect  circle.  (Been there done that)

 



Just goes to show how non airworthy a/c can fly in the USA and  hide behind

"its my freedom to do so - or right"        

  

 Well I wouldn't say that.  To  me "airworthy" is a relative term.  There are some aircraft that meet very  letter of their TC and shouldn't be in the air as far as I'm concern.   Take the B19 airliner.  No airplane should have all those extra  stabilizers just to fly straight and level.

  

 As for a "freedom" here in the  US - that's not quite correct.  The government issue us the  "privilege" to fly.  But in fact too, half the residents on my  airpark here in Florida are from England.  One even brought over his Tiger  Moth on floats.  Another brought his Chipmunk.  Please don't start  knocking my country.  It's the only one I have.

  	  Quote: 	
		  

BTW,    there is an SB on YAK 11 that said keep the gear lever in up position

in    flight. I deduce that other CJ owners may not be doing this. The    reason

being is to prevent damage to the U/C. The same reason exists today    on all

YAK types. 



	
 There was a debate here on the CJ,  on weather to put the gear handle in the OFF position after gear  retraction.  The argument was that it did not "wear out" the seals in the  actuators.  What wears out the seals is movement, not pressure.   Another argument was that it took the load of the compressor.  The truth is  that pressure is pressure.  The pressure is the same with the gear  handle UP or OFF and is controlled by the regulator.  The only  time the compressor isn't "working" and not sucking h/p off the engine, is  if it's output is dumped directly over board.  Some 18T's have this  feature.  I don't like it.  Just one more thing to go  wrong.

  

 The Chinese manual does say that  the gear handle should be moved to OFF after retraction.  This would not  work on the CJs that do not have up locks.  But I like to point that NOT  all manual procedures are correct.  A number of us that were once at PAA,  can point- very poignantly - to the lost of 3 great guys lost because they  followed Boeing manual procedures.

 



B,BTW it was Dan McCue in 2004 and apparently got 9G on the clock.  Can

anyone asses from the video what his airspeed was to be sure it was 9G?  Is

the 9G stall at approx 240 kts on a YAK 3? 

  

 It'd be interesting to see the Yak 3 flight  envelope ( G vs IAS ).  What would be the IAS at Va?  I have no  idea.  As long as the AoA does not go passed critical the airplane should  fly around it's circle.  The flight path of the Yak in the video, didn't  seem to be "panning out" and made that last part of the pull, pretty much  aligned with the fuselage's longitudinal axis and flight path.  That  indicates he was well with-in the G vs IAS envelope.   BUT I am  not an aerodynamic engineer. 



Any way I'll let yawl know what I find out  with my air problem.

  

 Jim "Pappy" Goolsby

 

  [quote][b]

cjpilot710(at)aol.com
Guest

Posted: Tue Nov 28, 2006 4:55 pm Post subject: Hmmmmmmmmm That ain't right.

 	  Quote: 	
		   	  Quote: 	
		  	
	
 Well I found out what the problem was.  The QS-1 valve was the  culprit.  It was full of rust and corruption.  I started the search by  pressurizing the system with nitrogen to replenish the system tank since it was  to low for a start.  In doing so I could hear air escaping from somewhere  in the belly.  I traced it to the QS-1.  I replaced it with one I  already had on the shelf.  Bingo problem solved.  Test flight with  some acro thrown in, showed all back to "normal".

  

 I can replace the rubber seal in the valve and the steel springs inside and  she'll be put on the parts shelf, well oiled and greased in a baggy.   

  

 Before this week-end I want to put her up on jacks.  Retract the  landing gear, than turn off the main air valve.  I'll than note  the time and gage pressure it takes before the gear starts to fall.   Somewhere I remember reading that the minimum pressure for gear operation was 25  atmospheres and minimum pressure for brakes was 10 atmospheres.  How  quickly the pressure comes down will depend on seal wear and condition but it'll  give me some idea anyway.

  

 It's kind-a nice going into the holidays knowing I don't have to change a  compressor (knock on wood).   

  

 Tomorrow I plan to take her on a short trip to New Smyrna to check on the  B-24.  Maybe take a look at those parts you never get to see unless the  mechanics have the lady (Witchcraft) all apart working on her.   Of course I'll have to take their beefs about how us pilots always break  things.

  

 God help me!  I do love it so.

  

 Jim (Pappy) Goolsby

  [quote][b]

N13472(at)aol.com
Guest

Posted: Tue Nov 28, 2006 6:17 pm Post subject: Hmmmmmmmmm That ain't right.

In a message dated 11/28/2006 4:57:36 P.M. Pacific Standard Time,  cjpilot710(at)aol.com writes:

  	  Quote: 	
		  Somewhere I remember reading that the minimum pressure for gear    operation was 25 atmospheres and minimum pressure for brakes was 10    atmospheres.  How quickly the pressure comes down will depend on seal    wear and condition but it'll give me some idea anyway. 	


 

 Pappy  with my plane on the jacks I have retracted in to the locks and  extended the gear to

 the down and locked position using shop air at 130 Psi or approx 9  atmospheres.   

 Tom Elliott  

CJ-6 NX63727

Sandy Valley  NV

3L2

702-723-1223



  [quote][b]

KingCJ6(at)aol.com
Guest

Posted: Tue Nov 28, 2006 7:44 pm Post subject: Hmmmmmmmmm That ain't right.

Jim - for those of us without immediate access to the manual, what/where is the "QS-1" valve?

  

 Thanks, Dave

  

 In a message dated 11/28/2006 4:57:36 PM Pacific Standard Time, cjpilot710(at)aol.com writes:

  	  Quote: 	
		   Well I found out what the problem was.  The QS-1 valve was the culprit.  It was full of rust and corruption.  I started the search by pressurizing the system with nitrogen to replenish the system tank since it was to low for a start.  In doing so I could hear air escaping from somewhere in the belly.  I traced it to the QS-1.  I replaced it with one I already had on the shelf.  Bingo problem solved.  Test flight with some acro thrown in, showed all back to "normal".

  

 I can replace the rubber seal in the valve and the steel springs inside and she'll be put on the parts shelf, well oiled and greased in a baggy.

	


 

  [quote][b]

ggg6(at)att.net
Guest

Posted: Tue Nov 28, 2006 7:59 pm Post subject: Hmmmmmmmmm That ain't right.

I'am not sure wheather this schmatic of the air system will come thur on the site, but will try to forward it. It shows what and where the QS-1 Valve is in the Sys....  Gary

  	  Quote: 	
		  -------------- Original message from KingCJ6(at)aol.com: -------------- 



   Jim - for those of us without immediate access to the manual, what/where is the "QS-1" valve?

  

 Thanks, Dave

  

 In a message dated 11/28/2006 4:57:36 PM Pacific Standard Time, cjpilot710(at)aol.com writes:

  	  Quote: 	
		   Well I found out what the problem was.  The QS-1 valve was the culprit.  It was full of rust and corruption.  I started the search by pressurizing the system with nitrogen to replenish the system tank since it was to low for a start.  In doing so I could hear air escaping from somewhere in the belly.  I traced it to the QS-1.  I replaced it with one I already had on the shelf.  Bingo problem solved.  Test flight with some acro thrown in, showed all back to "normal".

  

 I can replace the rubber seal in the valve and the steel springs inside and she'll be put on the parts shelf, well oiled and greased in a baggy.

	


 

 	  Quote:

CJ_Pneumatic_System_Schematic_Diagram.bmp

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dave(at)davelaird.com
Guest

Posted: Tue Nov 28, 2006 8:54 pm Post subject: Hmmmmmmmmm That ain't right.

On the CJ6 the QS-1 is the brake pressure reducing valve... pull the  

brake handle and the cable feeds down under the front cockpit and  

pulls a lever attached to this valve... the air comes out of this and  

goes to the QS-2 differential braking valve.  The position of the  

rudder pedals moves an arm on this valve which allows air to go to  

the left, both, or right brakes. Center the Pedals: air equally to  

both brakes.  Full Left Pedal:  air only to left brake, etc.



I had a similar leak to Pappy's last month, but it was my QS-2, not  

my QS-1, that was going bad.  My initial symptoms were loss of  

pressure during taxi and run-up... but ONLY if I had a lot of left  

pedal in... if I taxied/turned to the right I had no loss of  

pressure!   Well, maybe a small loss.... afterall....we do kind of  

dance on the pedals on these birds, so any jab of left rudder would  

leak some air out.  At first I didn't notice it because by the time  

you did a run-up the gauge would be back to 55 again...but after a  

time, the problem got progressively worse until I DID notice it!

I isolated the problem by opening the main air valve prior to start  

and pulling the brake handle and moving the rudder to full left  

deflection... you could hear the air go into the brake circuit...but  

unlike the right side, which would give a whoosh then the satisfying  

little "squeal" followed by silence when the right brake/line was  

full of air, the left side would go whoosh and it would keep gushing  

air out of the valve as long as you had left rudder held in...if you  

held it in long enough, all air from the main system would be  

exhausted in this manner.

You'd hear it under your seat, because that is where the sucker lives!

If you centered the rudder amidship, or pushed right rudder, the  

nasty hissing sound would go away.

I then opened up the access panel and with a helper, could feel the  

air coming out of the QS-2's front side.

So I bought a new unit ( actually a QS-2B) from Doug, installed it  

and all is well.



Dave Laird

N63536  1983 CJ-6A "Betty"

Dallas

dsavarese(at)elmore.rr.co
Guest

Posted: Wed Nov 29, 2006 4:44 am Post subject: Hmmmmmmmmm That ain't right.

For the Yak 52 guys, the QS-1 valve on the CJ6, which I  believe is located in the center belly of the CJ fuselage inside the large  inspection panel, is exactly the same as the Yak 52's brake reducing valve  located in the rear cockpit under the floor panel on the right side of the  control stick.   The parts are interchangeable.  So if your 52's  brake reducing valve goes T.U., and you can't find one from the 52 parts  suppliers, try our good friend Doug Sapp.

 Dennis

  

 [quote]   ---

flushjohnson(at)charter.n
Guest

Posted: Wed Nov 29, 2006 7:32 am Post subject: Hmmmmmmmmm That ain't right.

You dont have to replace the valve,overhaul with new seals from Sapp. Cost 

is 12$  for the QS2.

very easy to do.

---

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