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Review: Thrustmaster Pendular Rudder System By Tony Vallillo Oh, The Rudder. That littleunderstood and not-always-mastered flight control - the poor stepchildof the triad of aileron, elevator and rudder, named embarrassinglyenough after the primary control of... a BOAT! Oh, the lack ofdignity and respect! At least in the modern era. In the beginning it was not so. All early bird pilots knew therudder well, and were masters of its proper manipulation. They hadto be, or they died early; because in those antediluvian days of TLAR(that looks about right) aeronautical design, airplanes were prone toall sorts of deadly mischief if the rudder was improperly used.Coordinated flight was both essential to performance and difficult tomaintain in those old underpowered taildraggers of the so-calledGolden Age of flight. /images/reviews/thrustpr/t/img_0143.jpg The pedal portion of the TPR as it comes out of the box By the 1950's, when the CAA became the FAA, and Piper and Cessnawere beginning to rule the world of general aviation, the powers thatbe decreed that airplanes, particularly small airplanes, were to bemade safer by design. This was accomplished through such innovationsas tricycle landing gear and aeronautical designs that were moreinherently stable, particularly in the yaw axis. Over time, Cessnasand Pipers became much less prone to spinning, and much more tolerantof sloppy flight control or the total lack thereof, especially withthe rudder. In fact, early in the post war era, a plane was designedand put into production that had no rudder controls in the cockpit atall - the Ercoupe, which featured an interlinked control system thattied the rudder surfaces (the Ercoupe had multiple rudders, like aminiature Constellation) to the aileron axis of the control stick insuch a way as to always feed in the correct amount and direction ofrudder surface travel when the stick was moved from side to side. Spins were taken off the menu by the FAA's tactic of avoiding themaltogether by avoiding stalls as much as possible. Today the onlycivilian pilots who get spin training (other than those who search itout, mostly because they want to fly aerobatics) are flight instructorcandidates, and theirs is very rudimentary. The aviation world hasbecome somewhat acclimated to under-control in the yaw axis, a bitlike the way my hearing has become dulled by years of jet noise. So what should the rudder be used for today? Well, in all propairplanes the rudder comes into play at high power settings due to aconfluence of forces often known in the vernacular as P factor(although real P factor is only one of the forces). Also, allairplanes suffer from adverse yaw, which is an artifact of ailerondisplacement and results in a slight yaw against the intendeddirection of turn when a roll input is made. In addition, swept wingairplanes (and, some Beech Bonanzas) exhibit a tendency to yaw backand forth called Dutch Roll. And all multi-engine airplanes need agood deal of footwork with an engine out. Finally, there is alwaysthe crosswind situation to be dealt with both on takeoff and landing. /images/reviews/thrustpr/t/img_5617.jpg The Yaw Damper switches on the 767 overhead panel Jets are a bit different. Thanks to modern technology, jetairplanes don't need rudder inputs except for crosswinds and engineout situations. They have a system called the Yaw Damper to handleturn coordination and Dutch Roll damping. Modern Yaw Dampers can evenhandle most of the yaw in an engine out situation. Small planes,though, have to deal with all of the above tendencies, and it is alldone by the pilot with his or her feet; rudder control has been donewith the feet almost from the very beginning, first with a bar hingedin the middle that could be pushed back and forth, and eventuallythrough two pedals that work in opposition to each other. Again, onlythe Ercoupe was different. /images/reviews/thrustpr/t/336192_orig.jpg The Link Trainer, from the 1930's When flight simulation became a tool of flight training, in the1930's, the yaw axis was included, with rudder pedals in the crudesimulators like the famous Link Blue Canoe, known in the nascentairline industry of the time as the Captain Humbilizer! The depictionof rudder pedal movement and airplane yaw became more sophisticatedover time, and today the big FAA Level D sims all feature veryaccurate yaw response as well as yaw motion. On the other hand, thefirst PC based flight simulator, Sublogic Flight Simulator, had only arudimentary level of yaw included, and most of us (at least those ofus who were real world pilots) ignored it since there was, at thetime, no control other than the keyboard that had influence over therudder. Yaw modeling has gotten better over the years, particularlyin add-on airplanes, and eventually controllers were developed tobring access to the rudder away from the keyboard and within ourgrasp; literally, in the early stages, since the first yaw axiscontrol was a new axis of the joystick, which was constructed to twistleft and right in the hand to control the rudder (if selected). /images/reviews/thrustpr/t/rud.jpg Schematic of the Boeing 767 rudder control system This actually worked well enough that some of us, yours trulyincluded, stayed with it right up until today. This is, in part,because the first "rudder pedals" for PC flight simulation wereexecrable -- cheesy plastic toys that slid fore and aft and had nofeel and no impression of realism in operation. I tried them early onand was utterly underwhelmed. And so it was that I got used to thetwisting joystick, to the point that I occasionally wondered whyAirbus did not incorporate that into the A320 and its follow-ons. Since I was comfortable with the twisting stick, I was oblivious tothe development of more realistic rudder pedal hardware over the lastfew years. Indeed, it was not until I got involved in this projectthat I came to realize that there are actually a number of somewhathigh end rudder pedal products out there. But since I am not in anysense a cockpit builder (due to lack of computer knowledge and skill,if for no other reason) I was loath to part with any hard earneddollars for anything other than faster and more powerful computers andthe actual flight sim programs. Now fast forward to the day, around a month ago, that a large boxarrived on my front porch, mere days before I was scheduled to undergolong-avoided shoulder surgery. Thrustmaster had, as I indicated in myreview of their T-1 Flight headset, also offered to make availabletheir new Pendular Rudder System for my perusal and review. I hadseen these units in operation at Oshkosh, at the large and verypopular Thrustmaster exhibit in one of the main exhibit buildings,ironically in the very location where, years ago, Microsoft was once amajor exhibitor of the various iterations of Flight Simulator. TheThrustmaster booth was so popular, as it turned out, that I did nothave time to actually sample any of their products, so long were thelines awaiting a turn. But now I was to have my chance. I decided to at least unbox and assemble the TPR rudder pedal unitright away, before I went under the knife and lost the use of an armfor several months. Thus I opened the big box, and after extractingthe actual TPR box from the outer protective shipping box I set aboutassembling the unit. It comes very well cushioned in Styrofoampacking, and is insulated against all but the most determined effortsat shipping sabotage. My unit was in perfect condition, and aftergathering all of the pieces I perused the instruction manual for someassembly insights. This manual initially looks to be quitecomprehensive, being nearly the size of an old style paperback novel.But like so many others these days, the bulk is deceptive; it is amodern day Rosetta Stone, containing within itself enough languages tokeep the entire UN translation staff busy! The actual English portionis a mere 14 pages long, but it is complete enough that even amechanical tyro like myself can put the unit together without muchfuss. They thoughtfully include a full set of tools, so you need notrush out to Home Depot in the middle of putting this together. /images/reviews/thrustpr/t/img_0148.jpg Connecting the pedal to the brake sensor, with a variety of positions to choose from Fortunately for me there is actually little assembly required. Theonly things that need put in place are the pedals themselves, and thatinvolves only two operations - one to install the pedals and anotherto attach the pedals to the brake sensor unit. Although my fewmechanical abilities were stretched to the limit, these operations arein fact fairly simple (indeed, a normally adept person would find it acake walk!) and it was but a matter of minutes before the unit stoodbefore me in all of its splendor. /images/reviews/thrustpr/t/img_0144.jpg The massive pedestal unit - the heart of the system And splendid it is. To begin with, it is massive. It is said toweight around 15 pounds, about all I can heft with one hand. It istall - around 13.5 inches worth at the top of the tower that supportsthe pendulum action, and from edge to edge it is around 21 inches wide(all measurements are my own and are approximate - cockpit buildersand others interested please look at the Thrustmaster specs online).From front to back of the base plate it measures around 11.5 inches.It is mostly painted flat black, except for the pendular mechanism andthe pedals themselves, which are a flat aluminum color. The pedalsthemselves much resemble those on a big airplane, and are of an opendesign, with many cutouts, presumably to either lower the weight orthe wind resistance! The pedals are almost exactly as far apart asthey are on a Boeing, albeit about twice as far apart as theircounterparts on a Cessna. This has not proven to be a problem for mewhen simulating Cessnas, but if one's only actual real flightexperience is in Cessnas it might feel a bit different at first. Forsimmers without real world experience it is probably a moot issue. /images/reviews/thrustpr/t/img_0233.jpg The assembled pedal system The "action", the mechanism that allows the pedals to moverealistically, is a sizeable and robust looking construct of someingenuity; indeed, robust enough that it looks like it could have comeout of an airliner. The pedals are each attached to the bottom of afoot-long arm that looks like a replica of a bridge girder. This isactually an inverted L shaped affair that is attached to the tower atthe top where the angle of the L is. The remainder, the short arm soto speak, extends to the rear of the unit, where push rod assembliesconnect it to a "walking beam" of sorts that is attached to the rearof the tower on a bolt through its' middle. Thiship-bone-connected-to-the-leg-bone arrangement works in such a waythat when you push one pedal in, the arm moves to pull one end of thewalking beam up. The other end of the beam then moves down, whichresults in moving the other rudder in the opposite direction. /images/reviews/thrustpr/t/img_0145.jpg The rear of the pedestal, showing the walking beam connection between the pedals and the scissor spring that provides the "feel" for the rudders The middle of the walking beam is attached to a scissor-likearrangement that moves to extend two springs. These springs providethe "feel" for the system, and are adjustable in a variety of ways toprovide a range of resistance. Each pedal is also attached to asensor unit that measures pedal deflection in the brake axis, andsends the signal to the simulation to apply each brake, and by howmuch. /images/reviews/thrustpr/t/img_0235.jpg The assembled pedal showing the connection of the brake sensor The net result of all of this syncopated rhythm is that the pedalsmove straight in and out, just like the real ones. The brake pedalaction is also exactly like a real airplane with but one exceptionthat will be discussed in a moment. There is no comparison at all tothe simple rudder pedal hardware that slides in and out. Even some ofthe other higher end products would appear, from looking at thepictures, to feature at least a bit of curvilinear as opposed topurely rectilinear motion. The TPR's are the only pedals I have seen(a significant caveat to be sure, since I have such limitedexperience) that move more or less exactly like the pedals on a realairplane. /images/reviews/thrustpr/t/img_0236.jpg The pedestal, showing the mounting holes for secure positioning and slide-free operation So much for movement, but how do they feel? I have written beforeof the chimera of "feel" in flight simulation. In fact, feel issomething of a chimera even in the real airliners, particularly thosewith fly-by-wire or hydraulically boosted control systems, which meansjust about everything after the DC-7 (the 707 and DC-8 actually hadhydraulic boost on the rudder). Flight control feel in airplanes isthe result of several factors; specifically, the design and themechanical resistance of the flight control system itself, and theforces generated on the displaced control surfaces by the air flowingover them, which is transmitted back to the yoke or pedals through thecontrol cables. The mechanical resistance is the same all the time,but the air loads vary considerably - mostly due to speed, withincreasing resistance as the speed of the airplane increases. Insimple airplanes with basic cable and/or pushrod control systems,there is no need for artificial feel systems. But big airplanes withcontrol cable runs over great distances and flying at higher speedsend up with control forces that are beyond the ability of a pilot toovercome. Various schemes were employed over the years to assist thepilot in moving the controls, one of which is the servo tab, which wasfound on the early generation of jets like the 707 and was calledmanual reversion in the 727. Google this term if you want to knowmore. /images/reviews/thrustpr/t/img_5178.jpg The 727 hydraulic panel at the FE station. Starting with the 727 (in addition to the rudder only boost on the707 and DC-8), hydraulic systems running at 3000 psi were incorporatedto make movement of the flight controls a non-issue even for the 90pound weakling pilot! However, this took away all direct feedback ofair loads from the control surfaces, and without any additionalartificial feel would have resulted in the same yoke or pedal force atall speeds - a dangerous situation in airplanes that cruise close toMach one. Those of us old enough to remember the very first powersteering systems on cars know this phenomenon well. In aviation acomplicated system of artificial feel was created to place a varyingresistance on the control column and pedals, resistance that isproportional to the airspeed and that creates feedback to the pilot inmuch the same way that varying control "stiffness" is a key signal ofairspeed and angle of attack in small airplanes. When fly-by-wirebecame the rage Boeing, at least, engineered a similar system into the777 and 787, whereas Airbus seems not to have done that with the sidestick, which, according to pilots I know who fly those things, has noreal feel at all, just a spring like resistance. /images/reviews/thrustpr/t/img_5181.jpg Boeing 727 flight simulator showing the rudder pedal arrangement; again, very similar to the TPR So...the real challenge in flight simulation is to create controlloads that offer variable resistance on the yoke and pedals,proportional to speed. In FAA approved simulators at the airlinelevel, this is done with engineering equivalent to that used in theactual airplane; and is, as you would expect, quite realistic. Butnot completely realistic - even the Level D simulators are a wee bitoff. Only a pilot of the type would notice this, but I have neverflown a simulator that was truly 100% accurate in feel (actually, theairplanes also vary a bit from one to another depending uponmaintenance and how hard and wet they were "rode"! This wasespecially true in the C-5 Galaxy, and was likely due to the relativeinfrequency of flying that these airplanes did). In PC based flight simulation "feel" is usually provided by one ormore springs. In the beginning these were merely centering springs,like those found on the very early controllers on things like Atarigames. Eventually slightly more sophisticated systems were introducedthat allowed for a greater resistance toward the end of stickmovement. This is what we have in the Thrustmaster TPR pedal system.The multi-spring system allows for an actual increase in theresistance as you move the pedal farther along its travel. Thisspring system is adjustable, and you can increase or decrease thebasic resistance according to your taste. A real pilot might, forexample, want to adjust the system to come close to the feel of whathe or she is flying. I myself find the spring setting from thefactory to be very satisfactory and have not yet troubled myself toalter it. The resistance is fairly light in the first inch or so, andincreases as you get farther into the travel. There is a slight butdefinite mechanical detent at neutral, but it is not bothersome.Total travel of the rudder axis of the pedals is around 4 incheseither side of the center. The angle of the rudder pedals is also adjustable; that is to saythat you can have them pretty much vertical or you can have them laidback somewhat - actually to nearly 60 degrees off vertical. This toomight be useful to mimic a particular airplane. But this comes at asmall price, since you are using some of the brake pedal axis for thismovement, and you will have less travel on the brake axis. The brake action of the pedals duplicates the action of realairplane pedals very well with one exception. Whereas the rudder axishas, in effect, variable resistance through the range of motion, thebrake axis has only what feels like a centering spring apparentlylocated in the brake sensor unit. This means that resistance does notincrease as brake pedal deflection increases. Nor do there appear tobe any adjustments possible in this axis. This is a mild annoyance,and had I been in the room when they were designing this I would havespoken up for some sort of variable resistance in this axis as well,perhaps along the lines of the spring system they use for the rudderitself. Airplane brakes, like cars, have a definite varyingresistance as the pedals are pressed, and in fact at some point theyhave so much resistance that all movement ceases. This is because inlight airplanes the pedals are, in fact, hydraulic pumps for a closedsystem, and in large airplanes the pedals are essentially meteringvalves with their own feel. The TPR brake pedals are indeed springloaded, but they have what seems to the feet to be a relatively light"feel" that does not change all the way to the end of travel. Theeffect is not unlike a car that has lost its brakes. On the otherhand, the actual range of travel, which is around 2 inches or so, isvery realistic, for a big airplane at least. So much for feel. How do these pedals work with the simulationprograms to provide a realistic simulacrum of flight? The quickanswer is - very well indeed. First of all, the entire system isrecognized by all of the simulation programs that I have (FSX, FSX:Steam, X-Plane 11, FS2, FlyInside) so installation is quick and easy.The pedal system is seen as a separate X, Y and Z axis, and you canassign these three axes to anything you want, although of course it isright and left brake and rudder that we are interested in! In eachsim, you can select either the joystick or the TPR assemblyindividually when assigning axes of control. So it is easy to assignall of your joystick axes and buttons, and then switch to the TPR andassign the three axes to the rudder and brakes (there are no buttonson the TPR). All of the sims will save all of these assignments. Theone thing you may want to pay attention to would be to determine theeffect of having more than one control in charge of a given function -for example, using something on the stick or yoke to activate allbrakes. This particular situation does work, and I still have thetrigger set up to activate all brakes at normal application, but youcan get away with this because all brakes is a separate command fromleft and right brake. On the other hand, it does not seem to work toassign both the TPR and the twist of the stick to the rudder axis, norwould you probably want to. Once all is assigned and recognized, it's time to fly! Of course,I immediately gravitated to jets, and particularly to three that Ihave flown extensively in real life - the 767, 757 and the 727, all inX-Plane initially. Now unless I had troubled to input a largecrosswind (the crosswind limit on a 767 is around 30 knots!) I hadlittle to do with the rudder initially except for trying it out ontaxi as rudder pedal steering, which all jets have and which is usedprimarily for takeoff, landing, and long straight stretches oftaxiway. This function was very realistic to the real airplane, partof which is the result of some good coding on the part of Level D andFlight Factor, but a goodly portion of which is the movement and"feel" of these Pendular Rudders. Rudder pedal steering is usuallylimited, in big airplanes, to around 5 degrees either way, and the TPRfelt just like a real Boeing rudder system as I held closely to thecenterline, taxiing to and fro. Same thing for takeoff roll, withonly very small inputs needed, and pedal movement very much like Iremember it was in the real thing. Once you get airborne, of course,your feet retract along with the landing gear and remain flat on thefloor until it is time to land, if then! Of course if you are going to spend any money at all on rudderpedals, you will want to start playing in the deep end of the pond,and crank in crosswinds and, (gasp!), engine failures. With acrosswind, both the Level D and the Flight Factor airplanes startheading into the wind early on, thanks to very good flight models. Iimagine you would find the same behavior from just about any goodadd-on these days. This is where the rudder pedals come in,particularly with a crosswind at or near limits. It takes a goodlyboot-full of rudder to keep the nose going straight in theseconditions, and the TPR system makes it all very realistic, especiallywith the higher forces toward the end of travel - an area you willdefinitely explore thoroughly when you try this. Crosswind landings were a real revelation, for me at least, becauseover the years I have found the stick-twist-rudder to be less thanrealistic, even leaving aside the obvious difference in usage. Ofcourse I get all the fun I can stand from crosswind operations in reallife, and so it is easy to forgo this particular amusement in flightsimulation. But lo and behold, the TPR makes crosswind landings muchmore doable and realistic. In fact, and particularly with high-end GAadd-ons like the 172 and 182 from A2A, the maneuver is so realisticwith these pedals that I imagine you could make a decent stab attraining private pilot students in crosswind landings. It is almostas good as theRedbird Crosswind Trainer,and that is saying a lot! Pedal travel and the spring feel are both agood simulacrum of real crosswind operations, especially in theCessnas I fly these days. Of course you aren't a real airline pilot unless you can handle anengine out situation, and it is here that the boys and girls areseparated from the men and women. For years, while I was flying thereal ones, I used to prepare for recurrent training using the Level D767 and its various predecessors. This work always included engineout practice, which was made 10 times more difficult by the use of thetwist joystick, and also the lack of a copilot to hew wood and carrywater during the evolution. Although just about totally unrealistic,the practice was valuable because if you could do it with only thetwist of a stick, nailing it in the big sim with pedals was a piece ofcake. But now, as I discovered, the practice is much more life-like,as your feets get to do their stuff. /images/reviews/thrustpr/t/img_0914a.jpg Boeing 767 rudder pedals - very close to the size and spacing of the TPR The spring loaded TPR system is not quite as much of a leg-full inan engine out situation, but overall it is still very good. In thereal airplane, your leg might well start shaking from the exertion ofholding near full rudder deflection, at least until you got around tocranking in some rudder trim. If the "airplane" was heavy, this mightnot be soon. Indeed, the reason that simulator check rides becamepart of most airlines' interview process in the 1970's was the adventof women applicants at the airline level. There was, initially, someuncertainty in the minds of the men doing the hiring that the "gals"could handle something like a 707 with an outboard engine out. As itturned out, they could; and eventually the sim check turned into moreor less of an instrument check, although it still involves an engineout approach. /images/reviews/thrustpr/t/p1050812.jpg Cessna 172S rudder arrangement After I had tried and mastered V1 cuts and engine out approaches in757's and 767's, as well as the 727 (X-Plane only), I turned to thesmall plane world and the Cessna 172 and 182 from A2A in FSXSE, aswell as the enhanced 172 in X-Plane. Now things were more interesting,because although the engine out approach actually involves no rudderat all (!), just about every other maneuver does. Takeoffs becamethe pedal dance that they are in real life, with the TPR's providingjust about a perfect imitation of the travel and feel of Cessnapedals, if not exactly the same construction and geometry. Throw in acrosswind and the TPR's get a real workout, back and forth as the leftturning tendency battles with the weathervane tendency in crosswinds.Very life like indeed. The same on steroids for landings. I crankedin a 15 knot direct crosswind (the limit for small Cessnas) and foundthat the stick and pedal work was remarkably realistic, with theresulting flight path and landings ranging from a near crash toperfection, just as they do for me in real life! (OK, no near crashesin real life, but a few ugly landings, to be sure!) One thing about these, and likely any other computer rudder pedals,is that the way you set them up is important. The TPR's weigh around15 pounds, as I said before, and although you would think that wouldbe enough for it to stay put, it is not so. They will move aroundunder your inputs unless you have a way to anchor them firmly inplace. Serendipitously, placing them in front of my computer at thefoot of my desk left them firmly against the front of the desk, unableto move backward, which is what they may do if not restrained. Thiswas OK for the pedals, but my office chair, with wheels, ended updoing the moving! I had to replace it with a seat that would not moveso readily - an actual jumpseat from a 727 that I had liberated fromthe boneyard several years ago. Thus equipped, I had no more troublewith anything moving around. But most of you will want to permanentlymount these, quite likely in a home cockpit. The large base plate isequipped with a variety of holes for this purpose, so that you canbolt the assembly in place in your rig. Thus fastened, it will serveyou well, and probably for a long time if the appearances of ruggedconstruction reflect reality. /images/reviews/thrustpr/t/img_0237.jpg I was fortunate that my desk has a solid bottom, against which the TPR can rest motionless. My chair, however, was a different matter, and I had to use instead a 727 jump seat that I got a few years ago. The time has come, the Walrus said, to talk of many things...suchas -- how much do these cost? The answer to that is a few cents shyof $500 at MSRP. This is not a small amount, although it pales incomparison to such widely coveted niceties as a screaming graphicscomputer or the one-sided 737-800 cockpit rig from Flight DeckSolutions, to say nothing of the nose section of a real airliner. Isit worth it? Well, you might as well ask if flight simulation isworth it, or if thousands of dollars of add-ons is worth it. Comparedto the low end rudder pedals that you can have for more or less of asong, these should improve your "flight" experience considerably.Compared to a stick that twists, you will be in another universe, onethat is orders of magnitude more realistic than what you have beendoing, and this is particularly true if you are also a real worldpilot. Real pilots can stop making excuses to themselves aboutcertain unrealities in flight simulation if they step up to somethinglike the TPR system. Cockpit builders, especially airliner cockpitbuilders, will find that these are just about the most perfect looking(and performing) rudder pedals they can get at any price. Oh, if yournose section comes with a pair of real Boeing pedal sets, then you canturn your nose up at us mere mortals! But for anyone who will, forwhatever reason, forgo the delights of a real airliner nose section inthe bedroom or garage, the Thrustmaster TPR rudder pedals are aperfect way to go. Worth it? My guess is that you will know theanswer to that once you get them. /images/reviews/thrustpr/thrustmaster-tpr.jpg Happy (crosswind) landings. Tony Vallillo Learn More Here