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Modeling an A-6? A real walk around

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  • Member since
    February 2012
Modeling an A-6? A real walk around
Posted by ScottVA36 on Sunday, March 4, 2012 1:53 PM

I am saddened by the A-6 walk around’s out there most are inaccurate, as I have worked on them as a structural mechanic for 15 years. I feel I should enlighten some who find this aircraft fascinating. First I should state the basic aerodynamics of this beast, the aircraft was equipped with primary fight controls operated from the flight and combine hydraulic systems, those systems consisted of Flaperons(not ailerons), Stab, and Rudder these primary controls where electo/controlled,Hyd/actuated with the flight system hydraulics the main fluid support with combine hyd backup.

Secondary flight controls consisted  of flaps and slats these where operated primarly off the combine hyd system. There was a config term used in the  A-6 community call “Clean and Dirty”, clean was when the flaps and slat where up which limited throws to the stab 4 degrees LE up to 9 degrees LE down and the rudder to 5 degrees left or right. Dirty was when the flaps/slats where down a mechanism called the stab shift/rudder shift would put those flight controls into extended throws Stab 6 degrees LE up to 23 degrees LE down and rudder 15 to 18 degrees left/right   there are plus and minuses for these I just cant remember them.

Slats had one degree of travel and that was 26 to 28 degrees LE down, Flaps on the other hand had two  there was takeoff position 30 degrees and a landing position 40 degrees all dependant on flap handle position, a cable on a drum attached to the flap drive gear box shifted the stab/rudder to dirty/clean configurations.

Flaperons provided two functions, seeing as the A-6 had no ailerons the flaperon when actuated would spoil lift on the wing causing roll to that side so would act as an aileron. The A-6 had no spoilers it used the flaperons to provide that function upon landing when the weaight on wheels switch was engaged it would trigger flaperon pop-up utilizing the flaperons as spoilers this was done through an intrigue mechanism called the crab assembly.

If you find this interesting please let me know I will be more than happy to fill you in on most of the mechanical functions of this wonderful aircraft. I know how this aircraft functioned as I worked on her for many years in 3 squadrons and saw our last fly out of Pax River in 1997 sad day. 

A-6

"Let Us Intrude On Your Behalf"  

  • Member since
    February 2012
Posted by ScottVA36 on Monday, March 5, 2012 8:42 PM

Round 2.. the hydraulic system, there were 3 hyd systems available to A-6, Combine,Flight,and backup.

The combine system consisted of about 13 gallons of mil H 83282 hyd fluid it supplied power to all flight controls,Flaps,Slats,Landing Gear,and all subsystems.

Flight System supplied power to just primary flight controls all this controlled by 4 Vickers variable displacing pumps 2 per powerplant each engine had 2 pumps attached , flight /combine per motor .

The backup hyd system had its own reservoir and pump upon a total hyd failure this would kick on and give fluid to the stab and rudder which would allow limited travel to the stab and rudder only. The filter assembly depicted on model  kits in the fuselage speed brake area are the filters for the backup system.

The landing gear had a fail safe system called blow down in case of a hyd failure the gear could be blown down with nitrogen at 2450psi to get the gear down and locked this pressure was stored in 4 blowdown bottles 2 in the starboard keel ,one in the port keel ,and one in the nose wheel well . this option was a nightmare for us mechs to reset  and return to flight.

Im just trying to give some insight of this aircraft its probably boring to most but this aircraft had some ingenious functions and shold never have been retired Ive worked on F/A-18s my last few years and the saying was “lawn Dart”

Thanks for reading I’ll supply more info if interested   

  • Member since
    February 2003
  • From: Green Bay, WI USA
Posted by echolmberg on Tuesday, March 6, 2012 11:20 AM

This is great stuff Scott!  Thank you for sharing and WELCOME TO THE FORUM!!!  Welcome Sign

Just a couple of weeks ago I finished Revell/Monogram's EA-6B Prowler.  Yes I know it has inaccuracies in it but I really don't care.  To me, it looks like an EA-6B and I love the look of the Intruder/Prowler line.  I dunno...something about the shape and sweep of the wings seems purrrrty to me.  Very pleasing to the eye.

The info you're sharing is VERY welcome and I know I, for one, look forward to more.

Thanks!

Eric

Dre
  • Member since
    June 2007
  • From: here, not over there
Posted by Dre on Tuesday, March 6, 2012 3:28 PM

echolmberg

This is great stuff Scott!  Thank you for sharing and WELCOME TO THE FORUM!!!  Welcome Sign

Just a couple of weeks ago I finished Revell/Monogram's EA-6B Prowler.  Yes I know it has inaccuracies in it but I really don't care.  To me, it looks like an EA-6B and I love the look of the Intruder/Prowler line.  I dunno...something about the shape and sweep of the wings seems to purrrrty to me.  Very pleasing to the eye.

The info you're sharing is VERY welcome and I know I, for one, look forward to more.

Thanks!

Eric

Pretty much what he said...  do you have pics to go along with your walk-around?  That's where the insider knowledge is a god-send.

  • Member since
    February 2012
Posted by ScottVA36 on Tuesday, March 6, 2012 6:44 PM

Round 3 with a pic I will try and descibribe the function of the nose gear and use a number system to try and point things out.

First one of the unusual aspects of the nose gear is it’s a strut but one that’s upside down the oleo is on top, there is a reason for that will get to that in a bit.

Number 1 in the picture is a cable device called the “shrink link” because with the strut fully extened it would not fit in the wheel  well thus when actuated, the actuator is located at the top of the crank where the cable attaches at the top, the crank pulls the cable tight and draws in the lower half of the strut in about 4 inches, thus shinking the nose gear strut.

#2 this little device is the steering unit but it serves two functions steering offcourse via inputs on the rudder pedals with the button depressed on the stick in the cockpit. Second function is it acts as a shimmy damper it actually has a big coiled spring around it its visable on the outside of the unit.

#3 this is a cam assembly used to bring the tow link #4 aka launch bar to a stowed position up against the strut so it will fit in the wheel well it strikes rollers that are behind the wheels.

#4 the tow link is how the maintenance manuals call it to most it’s the launch bar for cat shots it had 3 positions  intermetate,stowed  and down to release it you would lift up on the j hook #5 and it would be suspended by a spring right behind the strut in between the wheels this position was mosly for maintenance, to dro-p it all the way down you pulled the lever #6 straight and it dropped ready for hook up on the launch shuttle, when the aircraft was at tension on the cats the holdback linkage would rotate the assemble down so hook #6 would be back in its place so when the gear retracts the tow link would be moved up in the stow position.

#7 Now to the crazy configuration of the nose strut, because cat shots are so violent and an A-6 can carry its own weight in ordance the strut had a thing called strut lock, without it the stut would bottom out in a bad way on a cat shot this served two puposes one prevent airframe damage and keep the jet at proper AOA for launch, when the throttle was at military 85 to 95% theres is a handle in the pit called the cat grip the pilot would rotate it and hold on to it and the throttle at the same time this is what would actuate strut lock it was a selector valve that cut of all fluid in the strut thus making it a hard strut it works only on combine system pressure and weight on wheels.

#8 this is the down lock a small cylinder used to lock the gear down and offcourse unlock the gear

#9 is the steering socket assembly funny thing is this is held on by one 2 inch nut.

Well that’s it in a nut shell hope you find this interesting,I will try and round up some more later

Incidently the EA-6B nose strut works the same

 

  • Member since
    October 2007
  • From: Scotland
Posted by Milairjunkie on Tuesday, March 6, 2012 6:57 PM

Welcome & please keep it coming as its more than interesting Yes

  • Member since
    January 2006
  • From: Earth
Posted by DiscoStu on Tuesday, March 6, 2012 10:11 PM

Great info!  I'm just starting Kinetic's A-6E.  Would love it if you had some good pit pics.

"Ahh the Luftwaffe. The Washington Generals of the History Channel" -Homer Simpson

  

 

  • Member since
    February 2012
Posted by ScottVA36 on Wednesday, March 7, 2012 6:52 AM

I will try and come up with a pic of the cockpit and explain as many of the functions i can remember being an Airframer i was an AMH im not to familiar with the BN's side. will try and post some tonight

 

"F-14's make movies A-6's make history!"

  • Member since
    April 2003
  • From: 41 Degrees 52.4 minutes North; 72 Degrees 7.3 minutes West
Posted by bbrowniii on Wednesday, March 7, 2012 9:07 AM

Dude,

You should publish a book!

Thanks for all this info.

'All that is necessary for the triumph of evil is for good men to do nothing' - Edmund Burke (1770 ??)

 

  • Member since
    February 2012
Posted by ScottVA36 on Wednesday, March 7, 2012 10:20 PM

 

Ok for the cockpit, like I said before being an air framer I never dealt much with the BN’s side of the pit I will try and describe some of the controls on the pilots side.

#1 is the emergency/parking brake handle puling it straight out set the parking brake,turning it clockwise allowed the brakes to function while the plane was being tow the guy in the cockpit while being towed was the brake rider pressure was supplied by an accumulator which could be pumped up to pressure with a hand pump in the that handles is located just to the left of the wing fold handle #17 it was spring loaded in the retract position you just pull it up and pump away (not fun) this could also be used to open and shut the canopy.

#2  this is the landing gear handle the position of the handle corresponds with the gear up being up and vise versa a switch to the left with the warning stripe is the manual over ride switch, another switch where the #2 is ,is called the isolation switch it was spring loaded in the up position so with the handle up the switch would go up and basically turn off hydraulics to sub systems that are not needed in flight ie.canopy,brakes,nose wheel steering ,wing fold locks, and a few other things.

#3 this panal of gages is the engine monitors like fuel flow, RPM, and EGT (exhaust Gas Temp).

#4 left and right engine throttles

#5 this is the cat grip with throttles all the way forward the pilot would rotate it clockwise and pull up this would engage strut lock and help the pilot to keep the throttle levers from going back down during a cat shot.

#6 this is the fuel management panel it controls all three fuel cells ,wing fuel (A-6 has wet wings) and any drop tanks onboard. The warning striped bar just aft of it is the fuel shut off switches

#7 this is the flap handle used to raise and lower flaps it had two detents for the 30 and 40 degree positions this was for using flaps/slat in normal hydraulic operation flaps/slats could also be actuated electrically in an emergency this was done with the switch #8 it had to be done sparingly as the motors would over heat fairly easy.

#9 these are the igniter switches used to start the motors.

#10 these are one of many circuit breaker panels

#11 Rudder pedals, by pushing the toe or the top of the pedal would actuate the brake.

#12 is the barber pole indicator it shows the position of the landing gear, flaps/slats, tow link and arresting hook

# 13 is the enunciator panel things would light up like strut lock, temp warnings and several other things.

#14 the round warning stripe button is the emergency stores jettison one push and all pylons would jettison anything attached to the plane.

#15 this is the canopy jettison handle, the white switch just above it is the normal canopy open/close switch.

#16  just left of the number and below the gear handle are the hydraulic gages 4 gauges for 4 pumps.

#17 is the wing fold handle it is a 2 position handle first detent actuated the lock cylinders(4 per wing) second detent would actuate the wing fold actuator thus folding or spreading the wings .

I will get to the function of the control stick in the next post. As always hope you enjoy this installment any questions I will try my best to answer.

 

“Let us Intrude of your behalf”

 

  • Member since
    December 2002
  • From: NYC, USA
Posted by waikong on Wednesday, March 14, 2012 3:51 PM

Wow, this thread is better than any walk around book that I've seen.  Thanks for sharing your insight and info, I too have the Kinettic kit and this will be a great resource for me. Much appreicated.

  • Member since
    June 2008
  • From: Iowa
Posted by Hans von Hammer on Friday, March 16, 2012 9:28 PM

Speaking of 1/48 Revell EA-6Bs, does the Qu--r  kit come with the "gold" canopy or not?  

BTW, Scott.. Let me echo the others in welcoming you.. Most informative thread for Intruder fans..

In fact, I wonder if there is or  would be a place for Veterans here to share a detailed "walk-around" of thier own aircraft or AFV in the same manner as yours, and keep them archived...  Myself, I've got a pretty intimate "relationship" with the M109A3 SP 155mm Hpwitzer, M992 FAASV, M101A1 105mm towed howitzer and it's prime-mover, the M35A2 2 1/2 ton truck, and the M548 Cargo Carrier Track (along with their assorted TMs)...

I know that everybody that builds SP Guns & artillery wants to do the M109A6 "Palidin", but the A2/A3s were the guns carrying the ball from Vietnam through the end of the Cold War... 

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