Q-talk 18 - PRACTICAL TESTING FOR THE AMATEUR TEST PILOT
- Category: Q-Talk Articles
- Published: Tuesday, 31 October 1989 06:11
- Written by Jim Masal, Quickie Builders Association
- Hits: 1943
Any builder/pilot who contemplates flying his airplane for the very first time will find, if he even cares to try, that a great many generalities have been written about flight-testing a new aircraft, but precious few specifics. Many builders learn the traits of their new creations by random, chance events...or by "accidental" testing, e.g. "Gee, I couldn't stop it in time and it just ran right into the fuel truck. I guess my brakes aren't adjusted right." Many builders are not utilizing the FAA mandated flight test period (25 hrs. certificated aircraft engines, 40 hrs. non-aircraft certified powerplant) profitably. They are not learning very much about their airplanes.
There have been far too many first flight accidents experienced by pilots who got bored taxiing around the airport, got a severe case of "ants in the pants" and took to the air without having enough of a feel for their aircraft. What follows here are some exercises to teach you about your aircraft. If these are carefully done, you will also have a written flight briefing to show some future pilot who may someday fly your plane (e.g. a future buyer).
AIRCRAFT MAKE AND MODEL _______________________
POWERPLANT _________________ N-NUMBER ________
PROP MAKE, DIAM. AND PITCH ____________________
I. BEFORE START. Perform your designers (QAC's) pre-testing checklist. Check every nut, bolt, cable, tube etc. for security. Check all controls and control surfaces for full freedom of movement and proper direction of travel. TAKE PLENTY OF TIME. BE SLOW AND DELIBERATE. This is NOT a normal pre-flight. As you look at a bolt, cable, etc. it will help focus your attention if you TOUCH the item with your finger as you look at it. Look for fluid leaks.
II. START THE ENGINE.
Did it start smoothly and quickly? ____________
Describe any problems? __________________________________________________________________________
Run the engine for 5 minutes to warm it up.
What is the idle RPM? __________
What is max static RPM? ________
Does the throttle advance smoothly? _______
Are instruments operating correctly? ______
Describe any discrepancies: _________________________________________________________________________________________________________________________
III. SLOW TAXI. Taxi the aircraft about as fast as a fast walking speed. Apply the brakes. Estimate stopping distance: _________ft/yds.
[ ] Adequate braking action
[ ] Inadequate braking (adjust brakes) [ ] )
[ ] Brakes pull right/left. Adjust brakes [ ]
Your aircraft should turn adequately to maneuver within the confines of your base airport. Taxi at a fast walking speed then apply full left rudder for a 360 degree turn.
Estimate radius of left turn: _________ ft/yds.
[ ] Left turn radius is adequate.
[ ] Inadequate left turn radius. Adjusted: [ ]
Taxi at a fast walking speed then apply full right rudder for a 360 degree turn.
Estimate radius of right turn: _________ ft/yds.
[ ] Right turn radius is adequate.
[ ] Inadequate right turn radius. Adjusted: [ ]
Taxiing at a fast walking speed, get the feel of the aircraft's turning ability by doing 5 figure 8 patterns in a clear area.
[ ] Completed.
From a full stop, with brakes fully applied, slowly advance the throttle. Note the highest RPM that the aircraft will remain stationary:
From a full stop, and in a clear area, no braking, smoothly apply a short burst of full power. Describe acceleration:
|Describe acceleration:||Describe deceleration:|
|[ ] Slow/sluggish||[ ] Slow/sluggish|
|[ ] Moderate||[ ] Moderate|
|[ ] Fast||[ ] Fast|
|[ ] Acceleration is adequate||[ ] Deceleration is adequate|
QUICKIE BUILDERS ASSOCIATION
IV. MEDIUM TAXI. Taxi the aircraft at a fast jogging speed. Taxi straight ahead then reverse direction 180 degrees to the left, taxi straight again then reverse direction 180 degrees to the right. Describe directional control:
[ ] Inadequate (describe) ______________________________________________________
[ ] Adequate
From a straight taxi at medium speed, taxi in a series of "S" turns by turning 10 degrees right and left of a straight heading.
Describe directional control: ________________________________________________________________________________________________
Tendency to ground loop (tailwheelers)? [ ] Y [ ] N
Repeat "S" turns at a slightly faster speed while turning 15 degrees right and left of centerline. Describe directional control:_______________________________________________________________________________________________
[ ] Adequate control in all conditions, medium speed?
Apply brakes at medium taxi speed:
[ ] Inadequate deceleration or Rt./Lt. pull?
[ ] Adjusted correctly
[ ] Adequate braking
QUICKIE BUILDERS ASSOCIATION
FAST TAXI. Do all runs from a full stop at the end of the runway.
RUN 1: Apply partial throttle only sufficient to taxi slightly faster than the previous medium taxi speeds. Taxi the full length of the runway.
Record the RPM used __________
RUN 2: From a full stop, SLOWLY advance the throttle. Accelerate to and MAINTAIN 40 mph. down the runway.
Record the RPM required __________
RUN 3: Accelerate to and maintain 45 mph.
Record the RPM required __________
Describe directional control during these first fast taxi runs _____________________________________________________________________________________________________
*** Before proceeding further you should be able to complete these runs down the full length of the runway with no deviation from the centerline. Once you can maintain control down the entire centerline you should increase the speed of each run in 5 mph increments until the tailwheel feels light with neutral stick force.
RUN 4: Accelerate to 50 mph. ROM required? _________
RUN 5: Accelerate to 55 mph. RPM required? _________
When you make a run when the tailwheel feels light or the airplane itself feels ready to lift, note:
Indicated Airspeed __________
RPM required __________
What is book stall speed? __________
When the airplane feels light on the runway, you should know that the next increment of power will put you into the air. Before you proceed to flight, practice until you can check the following. Remember that a little more patience and time spent at this point will save you 10 times the time and effort you may spend repairing damage.
[ ] Adequate braking control
[ ] Adequate directional control
RUN 6: Fast taxi at a speed 5 mph below the speed at which the plane feels light. Carefully exercise full right and left aileron with a neutral stick. Describe any effect on directional control: ____________________________________________________________________________________________________________________________________________
This is the one you've been working toward. If you have carefully done the previous exercises in taxi testing you should know quite a bit about your airplane's behavior. This should increase your confidence. However, some first flight anxiety is very normal, even healthy. Many pilots experience first flight "tunnel vision", i.e. their concentration is focused on a very few items; they can't casually look around at everything and absorb all the information coming at them. It may take several flights for your "vision" to open up so that you see all the instruments, feel all the sensations, and enjoy the outside scenery. In any event, try to get as much of the following information on your first flight as you can. Fill in the blank spots later on.
From a full stop and utilizing maximum runway length, smoothly apply full throttle.
Note maximum RPM __________
IAS at liftoff __________
IAS during climb __________
Max altitude achieved __________
Max IAS achieved __________
Max RPM achieved __________
Max CHT seen __________
Max oil temp __________
Max oil pressure __________
During your first flight you should do whatever maneuvering your confidence will allow you to do. Enjoy the flight. Note:
*** Whether you stall the airplane or not, remember the IAS that you saw on first liftoff will be very close to stall speed unless you deliberately held the plane on the ground. Keep this in mind on landing.
*** Limit flight time to about 30 minutes. In the unusual event that normal flight vibration is working something loose, you should be back on the ground doing a post flight check before anything gets serious.
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