Stick & Rudder

Test Pilot

IN MAY WE DISCUSSEDflight control systemfreeplay and centering.Building on April's in-troduction to f ly ingqualit ies we showedhow you interface withthe airplane throughits flight controls, whichcan affect the ease or diffi-culty of piloting tasks, andwe gave specific measure-ment techniques and somepractical "normal" flyingassessment suggestions.

This month we continuewith the pilot-airplane inter-face by stepping back fromfocused, component-leveltesting and exploring theentire cockpit environment.Our perspective is that of apilot about to make a demo flight,which seems the perfect time to eval-uate a cockpit, although it's certainlynot the only time. Try some of thesetools in your airplane, and let usknow what you discover.

The cockpit is your flying envi-ronment. You'll spend 100 percentof your flying time in this littleroom, so it's a good idea to makesure it's a friendly place, since every-thing from instrument panel layoutto seat comfort influences your fly-ing enjoyment. Take a hard look atthe cockpit and how you "fit" intoit. Little less-than-desirable charac-teristics can become prolongedannoyances after a few dozen hoursof flight time.

Once you climb aboard for yourdemo flight, you're likely to be busy.That's good, because you'll want toevaluate the cockpit while perform-ing typical piloting tasks. Thedrawback is that you can become soinvolved with flying the airplanethat you forget to notice everything.

Cockpit EvaluationA 20-minute assessment of your flying environment

ED KOLANO

If possible, spend about 20 minutessitting in the pilot's seat when theairplane is on the ground.

Ground EvaluationEvaluat ing the cockpit on the

ground gives you the time to be-come familiar with everything in it.Do this alone. If a salesperson ordemo pilot wants to show youaround the cockpit, fine, but youneed time to assess the cockpit with-out distractions. Perhaps you canarrange to be left alone after thecockpit tour.

What do you do after you'veclimbed into the pilot's seat? If youdo nothing but sit there, you'll havea better feel for seat comfort or lackthereof, but there are a lot of otherthings to check.

Cockpit entry. You performedthe first assessment by getting in theairplane. If you and your passengersmust climb on the wing to get intothe cockpit, can you do it, or willyou need to carry a step with you?

Once on the wing, isgetting a leg over thecanopy sill difficult?

On some high-wingairplanes the cockpitdoors are between land-ing gear and wingstruts, necessitat ing

some ducking and high-stepping for entry. Can youlive with this? Sometimesgetting in the door can be achallenge if the pilot's seatis forward relat ive to theforward edge of the door,and you may have to pullyour legs in with yourhands. Getting out is usu-ally easier, but don't forgetto evaluate this, too.

Shut the door or closethe canopy and determine

how easy it is to assess its security.Some airplanes have awkward lock-ing mechanisms that can be difficultto check visually. When closed, doesthe door contact your shoulder orarm? After you've evaluated thesethings, unbutton the cockpit if it's awarm day. There's no reason youneed to bake.

Adjust the seat. Can you place itwhere you want it for flying? If theseat slides fore and aft on tracks, ad-just it to where you can displace therudder pedals fully and actuate thewheel brakes and then strap yourselfin, because that's how you'll spendthe major i ty of your time in thecockpit. With the harness tightlycinched can you apply full forwardstick? Can you pull the stick or yokeall the way back, or does it contactthe seat or your belly? How aboutleft and right stick? Do you have tomove your leg to achieve full dis-placement? Can you do this whileapplying full rudder pedal?

If the seat is fixed (and the air-Sport Aviation 101

Test Pilot

plane doesn't have adjustable rud-der pedals) don't assume you canmodify this when you build yourairplane. An immovable object likethe wing spar may limit its adjust-ment. Be sure to ask about possiblesolutions if this is a concern. Tryall other adjustments. Some air-planes have rudder pedals t ha tad ju s t fore and af t . Other seatshave seat-back tilt angle and/orseat-height adjustments . Experi-ment wi th them all to f ind yourbest location, then ask yourself ifthe best location is good enough.

Are you wearing the clothing you'llwear when flying? Will bulky winterclothes affect your control displace-ment? Is there enough clearancebetween your head and the canopyor structural member to wear a head-set or he lmet? Wil l you wear aparachute? Is there a c o n v e n i e n tplace for your flight bag, charts, orlunch? What about your kneeboard?

Next, see how easily you canreach and actuate (or simulate actu-ating) all the levers and switchesthat control everything from thelights to the flaps and landing gear.Always keep safety in mind—do notactuate the landing gear retractionswitch or lever! Before actuating anycontrol that moves an external con-trol surface, ensure that bystanderswon't be injured by your action.

Look at the instruments. Arethey located where you plan to haveyours? If not, inquire about spacebehind the panel to make sure theywill fit. Can you read every instru-ment easily? Analog instrumentslocated to your left or right mayraise a parallax issue. Instrumentswith rotating indicators (needles)are designed to be observed directlyhead-on. When viewed from theside, the needle can appear to pointat a different value.

How about glare? You' l l need asunny day or overhead hangar lights tocheck this. Glare shields and instru-ment panel and windshield/ canopyangles affect this potentially annoying

characteristic. With permission, turn onthe displays (radios, engine monitors,etc.) and check their readability. If youintend to use digital instruments withLED or LCD displays whose readabilityis affected by ambient lighting condi-t ions , discuss your concern w i t h acompany representative.

You'll spend 100

percent of yourflying time in

this little room,

so it's a good idea

to make sure it;s a

friendly place.

Look all around. How's the view?Where are the b l ind spots? Can yousee your wingtips for taxi clearance?How about the main wheels? Tail?Will you operate in congested areaswhere seeing these features will benecessary? You can't do much aboutwhere these items are located, but tak-ing a conscious look at their locationsis good preparation for your flight.

Control EvaluationHomebuilt aircraft have such a

variety of control implementations,and if the airplane presents some-thing new, you've probably come to

grips with this already becauseunique flight control designs arehard not to notice during your demoflight preparation. Now it's time totry the control system on for size.

You've already moved the flightcontrols through their fu l l range oftravel. Do it again, but this timeth ink about flying the airplane. Willyour "normal" stick and throttlehands grasp these controls in thea i rp lane? The position of thestick/yoke and throttle determinesthis, and if they are opposite fromwhat you're used to, can you makethe switch? Most pilots arc remark-ably adaptable and can becomecomfortable with different flightcontrol arrangements after somepractice. Are you one of these pilots?

Which hand? If you think youcan switch hands to use your fa-vorite hand—except during takeoffand in the landing pattern, whereyou want immediate control of bothstick and throttle—think about itagain. This technique is certainlypossible, but it can lead to trouble. Ifcaught by surprise with the wronghand on the stick, you lose preciousseconds—and jeopardize controlwhile switching hands.

Side stick. These little controlsticks can provide a fighter-like feelto your airplane. They are fun to flybut generally preclude using yourother hand at all. If you plan to flyyour airplane IFR and write withyour stick hand, you'll have to re-lease the control altogether to copyclearances, frequencies, etc.

Stick length. Generally, longersticks have larger displacementsthan shorter sticks. Longer sticksgive you a mechanical advantagethat helps keep forces manageable,but they require a longer reach. Be-cause of the larger displacement, thedesigner can fine tune stick sensitiv-ity. Short sticks provide the samecontrol authority, but they do itwith less displacement. This canmean higher stick forces or an overlysensitive feel, which means small

102 JUNE 2000

stick displacements generate com-paratively quick airplane pitch orroll responses. The demo flight isthe best time to determine whetherthese concerns are valid.

Stick operating mechanism.Some sticks pivot traditionally. Oth-ers have different pivot points forroll and pitch. Some slide instead ofpivot, others slide for one axis andpivot for the other, and some sticksare not vertical during straight andlevel flight.

Single or dual controls. Do youneed a ful l set of dual controls, orwill a single set suffice? Some side-by-side airplanes have a single stickbetween the seats. On some center-stick airplanes the only throttle is onthe left, out of the right-seater'sreach, and others have dual throttleslocated outboard. If you plan to flyfrom either seat, you'll have to be-come ambidextrous. Don't forget toconsider rudder pedals and brakesfor the other seat if you plan to sharethe flying.

Rudder pedals. Traditional rud-der pedals move fore and aft ,remaining square to the pilot's feet.Others are little more than a pivot-ing bar that angles away from theoutside of the pilot's foot as it movesforward. Some airplanes have heelcups that force the pilot to displacethe pedals by ankle articulation in-stead of by moving his entire leg.

Wheel brakes. Toe brakes are thenorm in production airplanes andmany homebuilts, but some air-planes have heel brakes. Check thelocation relative to your normal footposition. Can you operate the rud-der pedals and both brakes easily?

A few homebuilts have a handbrake that operates both main-wheelbrakes at the same time. Is it easilyaccessible? Is it near the throttle(presumably you'll be using yourthrottle hand to actuate the handbrake)? Can you apply full brakeswithout interference, or must youcontort your arm?

Several canard designs don't have

separate brake pedals—you actuatethe brakes by further displacementof the rudder pedals after reachingfull rudder deflection. Don't forgetto allow for enough leg extension tooperate the brakes when adjustingthe seat.

Flaps. If electrically operated, is the

switch conveniently located? Is therea flap position indicator and can youeasily read it? Is the flap circuit breakereasily accessible in the event of a run-away? If mechanical ly operated,where's the flap lever? Lower and raisethe flaps to see how far the lever trav-els and whether moving it requires

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Sport Aviation 103

Test Pilot

any special body contortions. Doesthe lever interfere with normal pilot-ing tasks in any position?

Engine controls. Can you easilyreach and operate the throttle, pro-peller, and mixture controls? Quadrantor push-pull? Vernier control or fric-tion lock? If permissible, actuate themall. You may be able to substitute otherstyles in your airplane (ask a companyrep), but try them.

Other controls. If the demo air-plane incorporates any othercontrols, evaluate them. Cowl flaps,oil cooler doors, tailwheel lockingdevices, etc., fall into this category.

Adding to the ListEnsure that you evaluate every-

thing you can see or think of. Hereare a few more items for your con-sideration. Feel free to add to thislist; it is not all-inclusive.

Fuel system. Can you see andoperate the fue l selector whilestrapped in? What about the fuelboost pump switch? Are there fuelquantity gauges, or must you squintat a sight tube through a mirror?Can you quickly and accurately de-termine the fuel remaining?

Electrical system. Evaluate the lo-cation of the master switch, circuitbreakers, avionics, and other electricaldevices, switches, and instrumenta-tion. Can you quickly secure themaster in the event of an electricalfire? How about pulling circuit break-ers? Are switches that control differentdevices located near each other and ofsimilar shape? If so, what would bethe consequences of inadvertentlythrowing the wrong switch? This maynot be s ign i f ican t during a demo

flight, but note any personal discrep-ancies so you can remedy them whenyou design your cockpit interior.

Emergency Exit. In an emer-gency, can you and your passengersexit the cockpit in a hurry? Can youopen the hatch quickly with onehand? Can you do it with your eyesclosed? Can you get out with yourparachute on and without having toslide the seat back or execute otherpre-evacuation procedures?

Harness. Is it effective? You'll bebetter able to answer this questionafter your flight, but think about itnow. Is it a two-point harness?Three? Four? Five? If not, are therepotential attachment points formodification to suit you? Are thebelts comfortable? Can you stowthem easily so they don't lodgewhere they don't belong or dangleout the door?

As you perform all these sug-gested evaluations individually,remember that this is not howyou'll fly your airplane. During anormal flight many things happensimultaneously and sequentially,and the synergistic result can bedifferent from the isolated assess-ment. You can overcome this bysimulating various f ly ing tasks.Perform a mock takeoff, movingthe throttle and flight controls andscanning the instruments as younormally would.

Simulate airway navigation ifthat's how you intend to fly yourairplane. Copy a clearance onyour kneeboard, change the radiofrequency, and fiddle with theGPS. If you have to switch stickhands to accomplish these tasks,switch hands in the simulation.Get out an approach plate. Wherewill you put it? If you are a flight-seer, can you look around outsidewithout sh i f t ing your body orleaning your head? If you shift,do you make inadvertent controlinputs in the process?

Come in for a landing. Lower theflaps as you normally would. Slide

your eyes left and right to see what acrabbed approach would look like. Pullthe stick back to flare. Compensate fora slight balloon while closing thethrottle and working the rudder andailerons. Grease it on the runway, butdon't stop flying yet. Handle the cross-wind; track the centerline all the wayto a stop.

Notice Anything New?You have j u s t spent around a

half-hour in the pilot's seat. How'syour butt? Your back? Neck? If youare experiencing any discomfortnow, it will probably be worse on along flight. Track down the sourceof your discomfort and ask thecompany what you can do about iton your airplane.

Next month we'll explore yourflight test program. The focus willbe the f i rs t f l ight in your newlycompleted homebuilt or restora-tion. Whether you intend to makethis flight or have someone else flythe plane for you, you'll find nextmonth's Test Pilot packed fu l l ofuseful information.

Thanks to everyone who sent let-ters and e-mails with commentsand suggestions to Test Pilot. Pleasekeep them coming to Test Pilot,EAA Publications, P.O. Box 3086,Oshkosh, Wl 54903-3086, or edito-rial@eaa.org with TEST PILOT as thesubject of your e-mail.

Ed Kolano's three-day Flight TestTechniques Course will be presented atEAA Headquarters July 23-25. Time toregister is getting short and class size islimited. For information, call 920/426-6815 or e-mail education@eaa.org. •

104 JUNE 2000