Replacement Genuine 737 Throttle & Center Pedestal - Full Conversion to NG Style

The last few months have seen quite a bit of activity regarding the throttle quadrant and center pedestal, which has culminated in me selling my former TQ and pedestal and replacing it with an another "more suitable" unit.

Brief Recap

In an earlier post late in 2012, I mentioned I was converting my genuine 737-300 throttle to full automation.  A dilemma I faced was whether to keep the throttle unit as a 300 series throttle with the attached two-bay pedestal, or do a full conversion to make it similar to the Next Generation (NG) style. 

After careful consideration, I decided to convert the throttle quadrant to a full NG style, bringing the simulator in line with a 737 NG airframe for which the MIP is designed.

Stab Trim Switches

One of the biggest differences, apart from thrust lever handles, between early model throttle units and the NG units is the stab trim cut out switches.  On the earlier 300 series units, the switches are paddle / lever style switches while the NG uses toggles and T-Locks.  T-Locks are a safety feature and sit beneath the toggle switches and are spring loaded; the pilot must push down the T-Lock to activate the toggle.  

LEFT:  737-300 TQ with old style paddle-style stab trim levers.

To convert the trim switches requires cutting out the old switches and fitting new reproduction NG style switches.  This is a major task requiring precision work of a surgical nature.  Although reproduction switches can be made, the reproduction T-Locks don't operate as the real T-Locks should.  I did search for some genuine T-Locks and toggles, however, my search was fruitless as these parts appear to be reused by airlines.

Replacement Late Model Throttle & Three-Bay Center Pedestal

A friend of mine informed me that a late model 737 throttle quadrant was for sale.  This unit was in better shape than my existing throttle, included the genuine NG style stab trim switches complete with T-Locks and also had a three-bay center pedestal.  It appears provenance was shining on me as the new throttle appeared for sale a day before the stab trim switches were about to be removed (with a metal cutter...)

I purchased the new throttle and center pedestal (you only live once!).  The "old" 737-300 TQ has been sold to an enthusiast in Sweden.

Complete NG Conversion

To bring the new 737 throttle and center pedestal in-line with a NG airframe requires:

• Attachment of a NG style throttle lever shroud to existing aluminium levers
• Removal of TO-GA buttons and relocation to bring design in-line with a NG (the buttons are identical, but the housing is different)
• Painting of throttle housing and center pedestal from Boeing grey to Boeing white
• Painting of all throttle knobs from Boeing grey to Boeing white.

The biggest hurdle is usually replacing the trim stab switches, however, as these are already present on the new throttle, and are the NG style, I will save considerable time and expense in not having to replace them.

Main Differences - NG TQ Verses Classics TQ

The Boeing airframe that most people associate with today begins with the 737-200 and ends with the 737-800 NGX.  In between we have the classics which refer to the 737-300, 400 & 500 series airframes and the NG, which stands for Next Generation and incorporates the 737-600, 700, 800 & 900 series airframes.

The main differences between a classics and NG throttle quadrant are:

• The stab trim switches are slightly different; the classics having two flat levers while the NG has toggle-style buttons with T-locks
• The throttle thrust lever handles; the classics are bare aluminium and the NG is white aluminium that is ergonomically-shaped.  The TO/GA buttons are also positioned in a different place on the NG.  The knobs (handles) on the levers are also coloured white rather than off-grey
• The method that the throttle thrust levers move during automation.  The classics move both thrust levers together when auto throttle is engaged.  The NG moves each lever individually in what often is termed the throttle dance (this is due to the computerised fuel saving measures incorporated in the NG)
• The center pedestal in the classics is either a two-bay pedestal (early 300 series and before), but more likely a three-bay pedestal.  The NG always has a three-bay pedestal.  Base materials for the center pedestal are also different - aluminium verses a plastic composite material
• The speedbrake knob is very slightly more elongated on the NG unit
• The telephone, circuit breakers and mike assembly differ in type and location

737NG Thrust Levers – NG Skirt & TO-GA

Boeing when they designed the NG style throttle didn’t design everything from new; they added to existing technology.  All NG throttles utilise thrust levers which are identical to those of earlier units.  

Boeing designed a shroud or skirt that attaches over the existing thrust levers encapsulating the older thrust levers and sandwiching them between two NG style pieces.  The assembly is made from aluminium and is painted white.

The TO-GA buttons are located in a different position on the Next Generation units, although the buttons used are identical.

To alter the position of the TO-GA buttons you must detach  the small aluminium box from the 300 series thrust levers, remove the TO/GA buttons, and then re-solder the buttons in the appropriate location on the new unit.

I didn’t make the NG skirt for the thrust levers, but rather purchased a reproduction skirt from Northern Simulations in Florida.  The skirts are produced from aluminium and replicate the exact dimensions of the Boeing part.

Time-Line, Functionality & Conversion

The TQ is being converted to "basic" Flight Simulator use by Northern Flight Simulations

Following this, a good friend and I will be implementing quite a few new features to the throttle unit which will allow: full motorized functionality, full speed brake capability, accurate trim tab movement, alternate trim wheel spin speeds, correct park brake release, trim wheel braking and several other features. 

I want the functionality of the TQ to be as close as possible to that found in the real aircraft; therefore, the methods used to ensure this functionality will be slightly different from the norm.

When the TQ is fully functional and tested, I'll publish a post providing further information and detailed photographs of the various functions.

It's hoped evertyhing will be completed, and the TQ and pedestal installed by late May 2013.  The next month or so will be quite excting!!

Missing The Two-Bay Pedestal.....

I know I will miss the narrower two-bay center pedestal.  A major advantage that will be lost is the ease in climbing into and out of the flight deck; the two-bay provided more room between the pedestal and the seats.  At some stage, I probably will need to install J-Rails because the seats I'm using are fixed-claw feet Weber pilot seats; J-Rails will be needed to allow lateral seat movement.

BELOW:  Montage of several images showing main visual differences between 737-300 "classic" throttles and the 737 NG style throttle units. The 300 series TQ is my old throttle unit but, the NG TQ belongs to a mate of mine.

DZUS Fasteners

When I became interested in constructing a simulator, I heard knowledgeable people stating DZUS this or that - I had no idea what these individuals were referring to, let along how to pronounce the word.

LEFT:  A selection of real B737 DZUS fasteners beside a DZUS rail.

Dzus (pronounced Zooss) is a proprietary name for a type of quarter-turn fastener often used to secure skin panels on aircraft.

It was invented and patented by a native Ukrainian William Dzus (Volodymyr Dzhus) in the early 1930s. Quarter-turn fasteners are used to secure panels in equipment, airplanes, motorcycles, and racing cars that must be removed often and/or quickly.  These fasteners are notable in that they are of an "over-centred" design, requiring positive sustained torque to unfasten. Thus, any minor disturbance to the fastener will correct itself rather than proceed to further loosening as it would in threaded fasteners.

Real DZUS Fasteners

Finding individual real DZUS fasteners can be difficult as they are mostly attached to avionics panels, and the vendor wants to keep them with the panel.  If you search long enough, eventually you will find an aviation scrap yard that has them available as separate units.  I recently saw several selling on e-bay quite cheaply.  I have a small collection of grey, black and bare metal coloured fasteners in varying condtion, obtained from a scrapped Boeing B737 (I bought them in a 30 piece lot).  The fasteners are needed to lock down any avionics panels (real or FS) to the DZUS rails of the real B737 avionics bay (centre pedestal) I’m using.   

Reproduction DZUS Fasteners

If you’re using a real bay/centre pedestal with a DZUS rail, then FS avionics such as those produced by CP Flight or Simso will not be able to secure to the rail easily.  You will need to enlarge the circular hole along the edge of the module to allow the real DZUS fasteners to fit easily and correctly.  Be very careful that you don’t damage the edge of the module when you enlarge the circular hole.  I used a titanium drill bit and carefully secured the FS module in a vice on a workshop bench (wrapped carefully to avoid the vice jaws damaging the module)

If you have replicated your bay from MDF or wood and want to use something more realistic than “boring” screws to attach your modules, you can purchase aftermarket “look alike’ DZUS screws.  Basically these are wood screws with DZUS style heads on them.  Two suppliers of DZUS screws are SISMO Soluciones and GLB Flight Products.  I’ve used these on my earlier generic slight deck and they work very well and look just like the real ones…

"Sticky" Auto Throttle Button - Repaired

I noticed soon after the TQ arrived that the engine number one auto throttle button was a bit “sticky”.  Depressing the button, it would stay pressed in for a few seconds even though pressure had been released.  The A/T buttons are one-way buttons meaning that they are click buttons – click in, release, and click out.  It’s probable that after many hours of service, sweat, dead skin cells and dirt has built up on the inner button behind the spring mechanism; a friend suggested that DNA analysis of the built up debris would probably provide a list of suspect pilots!

Whilst the button was still in place, I attempted to loosen the built up material using a can of pressurised electronic cleaner fluid.  The fluid, I hoped would dislodge any loose material before evaporating.  Unfortunately, this didn’t work in the long run, although once lubricated with the evaporative solvent, the button operated correctly for a short time.

Circlip

The button is held in place within the throttle handle by a ½ inch circlip.  Beneath the circlip and button there is a spring mechanism that pushes the button out after being depressed.  Using a pair of specialised circlip pliers, I very carefully removed the circlip making sure that the spring mechanism of the circlip didn’t propel my A/T button out the window and into the garden! 

With the circlip removed, the inner portion of the throttle handle slides out revealing the button and attached wiring.  The button is a modular design (shaped to fit inside the thorottle handle) and unfortunately cannot be disassembled further, Therefore, I reassembled the button and sprayed a small amount of silicone spray around the button, allowing the silicone solution to penetrate around the the edge of the button. 

The silicon lubricant (which is non conductive, so there is no issue with power shorting) seems to have solved the problem as the button no longer sticks, however, this is only an interim solution.  I'll search for a replacement button module.  Sometimes the most simple solution will fix your problem!!

No doubt I can purchase a new replacement from Boeing for errr $800.00....  I think not.  Eventually I'll find a disused button module in my travels.   If you find a B737 on the line and note the captain side A/T button has been removed - you know who "stole" it  :)

Throttle Teething & Calibration Issues - It Was Expected

The throttle quadrant works well and I’m pleased with the outcome; however, as anticipated there are a few minor teething issues that require sorting.  There is a background “hum” noise, The engine one auto throttle switch is "sticky", and there are some minor issues with the calibration of throttle reversers and the speed brake. 

Background “Hum”

When the phidget software is turned on with FSX there is an annoying background “hum”.  Initially, I thought this background hum to be the low frequency AC noise, but then realized that everything is DC – so there shouldn’t be any noise.  After consultation with my technical engineers, I believe the cause to be either of the following issues:

1: When the phidget software is turned on it’s activating power to the servo motor to deploy the speed brakes.  The servo motor is ready and waiting for a command, but as there is no command for movement and the  servo motor has power running to it, it’s humming.  If this is the reason, then the installation of the Phidget 004 card (pictured left) will solve this issue. 

A Phidget 004 card has four relays which allow for three situations – on, off and always on.  When connected, the relays will tell the servo motor to “switch off “until activated by movement of the speed brake.

2: All power to the TQ is via 400 watt computer power source and a bench-top voltage reducing board (see last post).  I’ve been told that because all the power requirements are coming from a singular source, then this maybe a cause of noise.  The easiest method to solve this is to use two or three independent power sources.

I’ll have a better indication to root of the “noise hum” problem, once a Phidget 004 card arrives in the mail.

Speed Brake Calibration - Auto Deployment of Handle

Calibration is always an issue when simulating a complex piece of machinery such as TQ.  Calibration must take into account the various positions and operational requirements of the speed brake.  The speed brake must be recognised by the flight software in the following positions: off, armed and part/full detent.  It must also be configured to automatically activate (deploy) upon flare and touch down when the landing wheels touch the ground. 

The Boeing Operations Manual states: the thrust reverser can be deployed when either radio altimeter senses les than 10 feet altitude, or when the air/ground safety sensor is in ground mode.  Movement of the reverse thrust levers is mechanically restricted until forward thrust levers are in idle position.

Once touch down in achieved, the mechanical speed brake arm on the throttle quadrant will move automatically to the deployment position (full detent).  This is done by programming a squat switch.  A squat switch is standard on/off relay that tells the brake to either deploy or remain in the non deployment position.

Squat Switch & FSUPIC Programming

To program a squat switch I used  Phidget 004 card and programmed the F2Phidgets software to read "squat switch" in the interface.

To ensure that the speed brake was calibrated to FSX correctly I used FSUPIC.  One important aspect of the calibration is to ensure that the speed brake handle matches more or less the same movement of the virtual speed brake handle within the throttle of the B737 in FSX.  To check this you must open the throttle in FSX and actually observe  the virtual movement of the handle while manipulating the real handle.

Using FSUPIC, open the Axis Assignment tab and move the speedbrake handle checking that the arm and detent positions are correct.  Select "send to FSUPIC" and tick (check) the spoilers in the call out box.  Finally save the adjustments.

If you have not done so already, it's a good idea to have a FSUPIC profile set up to ensure that your changes are saved to specific aircraft.  For example my FSUPIC profile is called B737 Project.

Reversers

Once a Phidget 004 card is installed and the card relays calibrated appropriately to the speed brake, it’s hoped that the calibration of engine 1 and engine 2 reversers through detent position 1 and 2 will be straightforward.

After consulting with others and solving these issues, I'll post an update to this thread (here).  Perhaps the information may benefit someone else doing a similar throttle retrofit.

Update on Tuesday, December 6, 2011 at 10:54PM by FLAPS 2 APPROACH

The hum is now gone.  The reason was straightforward; there was no commands being issued to the servo motor, so the motor was making a noise.  Once a command was directed to the motor, the noise disappeared.  To stop the motor from being turned on when there was not a command; a phidget relay was connected (on/off).  When the command is issued, the phidget relay opens and when the command is rescinded the relay closes and power to the motor is stopped.  Unfortunately, the continual power to the motor caused the motor to present with problems.

Reverse Thrust Levers

This also was relatively straightforward to solve. 

My problem lay in the fact that I was trying to program the reverse thrust levers to read three power settings (three detents) as in the real B737 aircraft.  The first detent/notch on the reverse lever opens the clam shells/buckets to redirect air, the second detent/notch provides 50% idle thrust and allows minimal thrust and noise, thereby minimising the chance of suction of foreign bodies from the runway into the engines.  The third detent/notch applies full reverse thrust.  The third position is rarely used as it can easily suck foreign bodies into the engines from a contaminated runway causing engine damage - the exception being in very wet and/or snow conditions, when it is regularly used.

Unfortunately, programming the reverse thrust levers like this is not possible as flight simulator does not have the appropriate logic. 

Using FSUPIC to assign buttons & offsets

Once I realized this (with a little help from a real world 737 pilot and FS simmer), it's easy to program individual thrust to engine 1/2 using FSUPIC.  In FSUPIC, you assign a button to each of the reverse thrust levers and then assign a FS command (throttle set 1 and throttle set 2).  An offset parameter is required for each throttle which is -16384 / 0.  You also must ensure that the repeat box is checked.

Real World Throttle Nuisances – they had me baffled for a time

One aspect that baffled me for sometime was the changing of the FSUPIC button sequences as I activated the reverse thrust levers. In the first detent, each lever would indicate in the FSUPIC button assignment box, an individual and correct button number.  However, as the levers travelled through the second and third detent positions this button would change and both levers would indicate button 4.  Button 4 is assigned to the speed brake lever.  Why was button 4 continually being activated? 

It was then realized that at the forward end of the speed brake handle, where the brake arm recesses into the throttle, there is a small button.  This button had been wired to button 4.  Button 4 is activated when you either raise the brake handle to arm/deploy the speed brake, or when a cam is activated by the reverse thrust levers (the levers travel over the cam as they pass detent two and three position). 

Therefore, as the thrust levers were placed into the first detent, they were correctly operating the FSUPIC assigned buttons and offset.  But, as the levers travelled through the next two detents the levers physically cross a metal cam which automatically activates the speed brake which is why the button assignments were changing to button 4.  This is the method used in a real aircraft and it has been mimicked in the simulator – neat!

Speed Brake Calibration

This is far more difficult and challenging than I thought it would be.  I've spent many hours attempting to have the TQ speed brake operate in the correct manner, but have failed on all counts.  Without going into detail, sometimes it "sort of" works and at other times it fails.  The 004 phidgets have been installed and the two relays programmed (squat switch), however, for some reason problems continue.  The hum that was present has disappeared as the relays now stop power going to the motor continually.  Power is only directed to the motor when the speed brake arm is actually mechanically engaged.

This is going to require some in-depth thinking and help from others.  It’s possible that a problem exists with the servo motor.

Continuing the above theme, I've just spent a few hours talking to a friend in the US discussing this issue. It seems that it's highly probable that, during the testing and configuring I've done before the installation of the phidget relays, that I've burnt out the servo motor that operates the mechanical movement of the speed brake. The intermittent behaviour and motor "humming" was most likely caused by the motor beginning to over heat which lead to eventually motor burn out.  A new motor has been ordered and hopefully, with the aid of the phidget relays will not burn out.

In the meantime, everything else on the TQ appears to work correctly, which includes using the actual speed brake lever on the TQ to arm, partially open or fully deploy the spoilers.  The only aspect of the TQ that does not "yet" work correctly is the automated movement of the speed brake lever when the squat switch is activated on landing, and then when the throttles are powered up to close the spoilers - we need the servo motor to do this.

I'll add to these updates once the replacement servo motor arrives.

B737-300 Throttle Quadrant & Center Pedistal - Arrived at Last

A big orange truck from TNT Express parked outside the house this afternoon and the driver began to offload a large wooden crate that weighed around 80 kilograms.  I could be only one thing – the Boeing throttle quadrant and avionics box (center pedistal) had finally arrived.   

Together, the driver and I manhandled the crate through the hallway of the house to the room in which construction of the simulator is taking place.  Removing a heavy piece of machinery from a wooden crate can be tricky, and the only method was to disassemble the box screw by screw – WOW what beauty!

Initial Thoughts

The throttle and avionics bay is a genuine aircraft part so there wasn’t much to not like; you can’t “immerse” yourself or get a more authentic experience than by using a real aircraft part.  The throttle originally was in use in a Boeing 737-300 with South West livery.  Unfortunately, the guy at the tear down yard didn’t document the tail number of the aircraft it was removed from.  It would have been nice to have a photo of the actual aircraft to place on the Blog.

The first aspect I noticed about the throttle was the build.  It’s a solid piece of engineering built to withstand the neglect of pilot use and now simulator use.  I don’t believe the throttle will ever be damaged from neglect my end – its’ solidly constructed.  The feel when you push the two power levers forward is - well – you just have to be here!  Manoeuvring the flap lever through the various indents is equally rewarding.  Knowing that the throttle was once used in a real aircraft by real pilots adds a completely new dimension to flight simulation.

Retrofitting & FS Connectivity

During the refurbishment of the throttle, I had decided to not bastardize the throttle to try and replicate the appearance a throttle from a Boeing NG.  Therefore, the throttle remains a 300 series throttle.  It has been repainted only where necessary and decals have been replaced only when they were unreadable.  The internal mechanism of the throttle has been completely striped, cleaned and serviced.  Parts, such as the huge cog wheels and unnecessary internal wiring have been discarded as these are not required for simulation use. 

To allow the throttle to connect correctly with flight simulator, three Phidget cards (0066 & 0064) & a Leo Bodnar card (BUO 836X) have been used.  The cards are connected directly to the front of the throttle casing and will not be visible once the throttle casing is connected to the centre stage of the main instrument panel (MIP). 

All the functions of the throttle operate with the exception of the stab trim switches, which can be linked to another FS function if required.  Trim wheels are functional with the use of a servo motor and the trim spins when electric trim is activated on the yoke.  Back lighting is integrated back lighting (IBL) using genuine Boeing 5 volt bulbs.

Current Status

At the moment I’ve only taken delivery and am in the process of connecting a Benchmark card to an external power source to allow power to reach the 5 volt lighting bulbs and servo motors.  I have little doubt that there will be teething issues with software as I configure everything for correct functionality, but I believe that this extra effort is worthwhile to be able to use a real throttle instead of a replica.

Avionics Bay

The avionics bay is a two-bay type.  Two-bay types were mainly used on the earlier Boeing classic series jets up to the 200 series, however, a number of 300 series aircraft used them as well as 400 series.  The bay was attached to the throttle when I bought it, so rather than dump it and replicate a NG three-bay; I’ve decided to use it to maintain authenticity.  I may at some stage in the future replace it with three-bay – I’ll see how things develop once I begin to populate the bay with avionics instruments.  One benefit of using a two-bay style is that once Weber seats are fitted to the flight deck there will be more room to squeeze past to get into the seat!

An interesting feature to the unit is the positioning of two oddly shaped aluminium pull downs.  At first, I had no idea what these were used for.  Then it dawned on me – they are pull-down coffee cup holders.  What more can you ask for (laughing).  See the image gallery for a snap.

Fire Suppression Module

The fire suppression module was an afterthought.  A second hand unit was available and I decided to retrofit this with limited functionality to flight simulator.  At the moment IBL works, and when pulled, each fire handle does what it’s supposed to do.  At some stage in the future I may activate the fire bell.  But, at the moment it’s early days with regard to this.  Basically it’s a module that has to be installed into the avionics bay for aesthetics; a TQ without a fire suppression module looks a slightly naked.

More on the actual avionics bay at a later stage when I begin to populate the bay with instruments - much kmore interesting than looking at "naked bay"

• Click to read earlier posts regarding the throttle quadrant.

• To see a selection of detailed images of the TQ, check out the Gallery Section

Boeing Style 737 Clock

Whilst waiting for the MIP to arrive from Flight Deck Solutions (there has been a construction delay), I came across this genuine 737 style clock for auction on e-bay.  The clock has been removed from an American Fed Ex aircraft and has been serviced to new condition.  The price I paid was very reasonable and my thoughts were it would make a very nice addition to the MIP to replace the stencilled clock or reproduction clock.

I'd like to try and get the clock working with the simulator, however, I have been led to believe this is quite difficult.  Therefore, I may just contend with the fact that it's a nice looking 737 style clock that adds to the ascetics of the MIP.

Genuine aircraft parts are generally inexpensive and often less than their reproduction simulation counterparts.  Whilst conversion of a genuine part to flight simulation status can be difficult for the technologically challenged, it isn't impossible.

If you want your simulator to appear as "real" as possible or are seeking realism, then genuine aircraft instruments added to an assortment of flight simulation instruments adds a tangible feeling to the overall simulation.

Update on Wednesday, October 5, 2011 at 10:41PM by FLAPS 2 APPROACH

I've received several e-mails asking where I found this clock and how much I paid for it. 

I discovered the clock on e-bay and the price was a tad over $100.00 USD with freight.  The freight was almost the price of the clock!  A fair price in my opinion for a serviceable 737 style clock.

Now I have to figure out how to convert it to FS use.

Boeing 737 Fire Suppression Panel - Arrived

All excitement here!

A short time ago I received an e-mail from a friend, who had earlier discovered a 737 fire suppression panel in a tear down yard.  A bit of negotiation with regard to price and it's now mine.  It's currently sitting in Florida and will be installed into the centre pedestal by Northern Flight Simulations which is the same company that is revamping my 737 throttle quadrant (see earlier post). 

The attached photographs are what the unit currently looks like; a little bashed about with damaged labels and chipped paint.  But, overall the FSP is in good condition.  Once it's cleaned up and refurbished it will look almost like new. and, as I've said in earlier posts, there is nothing better than a real aircraft part!

I'm still undecided whether to wire the FSP into the simulator with more or less full functionality.  I've been told this is feasible, however, operation will only be through an instructor console.  In other words, a fire will need to be artificially generated in an instructor station, then the appropriate fire handle can be pulled to extinguish the fire and stop the engine.  At the very least, the panel will be correctly back lit.

I'll post some further "before and after" pictures once the unit arrives.  The photographs here are shots of the panel before being revamped.

The FSP is not an item you use regularly, if in fact at all.  However, inclusion of the FSP is mandatory if you are striving to attain a certain degree of authenticity and realism in your flight simulator.