Preflight Checks
Don Brooks
Spinning at just above idle, the propeller of the Spitfire flashed in the warmth of the bright noonday sun as the airplane turned from the taxiway onto the runway. It was a perfect day for flying: there was no wind to speak of, and the sky was almost cloudless.
The pilot advanced the throttle. Bouncing slightly across the rough grass field, the tail lifted and the airplane's moving shadow provided a sharp contrast with the grass. The bright-red-and-white marking on the fin provided a center of attention to rivet the observer's eye.
The motion of the airplane smoothed out as the speed and lift increased, and the Spitfire lifted from the grass to climb easily skyward. The observer savored the beauty of the flight's beginning; it all looked so real.
The Spitfire flew straight ahead until it reached an altitude of several hundred feet. The pilot's hand moved the control stick to the right to start his departure turn to the right, and all heck broke loose.
The Spitfire rolled lazily to the left and then suddenly into a steep dive, headed for the ground in a mighty hurry. For an instant, the pilot gave opposite aileron and pulled back hard on the stick. The airplane zoomed close to a willow tree on the canal bank next to the runway and then started a steep climb to the right. The bottom of the zoom could not have been more than 30 feet above the ground.
The observer watched, eyes riveted to the airplane, as the sequence began all over again. The airplane leveled out, began a roll to the left, and pitched down into a steep dive. This was followed by a high-speed pullout scarcely 50 feet from the ground, as the pilot fought with the reversed controls to keep his prized airplane away from the willow and out of the canal.
The pilot yelled to the observer, "The ailerons are reversed! Come reverse the aileron control for me!" In a panic now, the pilot ripped the reversing switch cover from the radio and tried to point to the aileron switch, all the while keeping one eye on the Spit, now about to climb out of sight.
The observer could hardly see the aileron switch because the pilot, overcome with concern for his model, was shaking so hard that the transmitter was vibrating up and down. The observer grabbed the side of the transmitter to steady it, found the aileron reversing switch, and reversed its position.
The quality of the flight improved instantly. The pilot could now devote his full attention to flight trimming. He made a low pass over the field and heard and saw a noticeable vibration in the horizontal stabilizer. Reducing throttle, he landed the model safely, only to discover that the horizontal stabilizer had broken on both sides of the fin. It was held together only by the trailing edge of the stabilizer and the fiberglass along the leading edge. The steep dives and high g-recoveries had taken their toll.
In the situation just described, I was the observer and the pilot was a friend flying a model of the famous WW II Spitfire on its initial test flight.
Anxious to get airborne and having just installed the radio the night before, my friend had neglected to check the direction of motion for the aileron controls. He did not use a preflight checklist to systematically check each function of the model prior to takeoff. This oversight almost cost him the model, to which he had devoted hundreds of hours of effort.
Could this near-loss and the damage to the model have been prevented?
"Sure," you may say, "all he had to do was forget the ailerons and fly the model with rudder only." This is easy to say, after the fact. A better alternative would have been to perform a thorough preflight check to verify proper operation of the ailerons and all other control functions.
Unfortunately, preventable model losses still occur. In 20 years of Radio Control flying, I've seen many flights end prematurely. Many of these model losses could be prevented. Many times the cause of the crash was forgetting to check a critical item during the preflight preparations.
For example, as his airplane lifted off the runway, I heard a flier shout, "Look out! I ain't got it! Heads up!" Helping the modeler pick up the pieces, one of the questions I asked was, "When did you last charge the battery?" After a moment in thought, he replied, "Last week, I think." This modeler relied on a days-old battery charge and didn't check the level of charge with a voltmeter prior to flight.
We can improve our chances for a successful flying day (that is, a day judged by having the same count of model pieces at the end of the day as at the beginning) by doing a good preflight before the first flight of the day. Airline pilots do it for every flight.
Use a preflight checklist faithfully and it will reward you with more flying time and much less building time. Here is a list of real boo-boos I've seen that are simple to prevent:
- Turning on the radio without the frequency pin. This usually costs someone else an airplane.
- Battery not fully charged, or with a bad cell. Both of these conditions would be detected with a voltmeter check of the battery condition. A bad battery cost a big rebuild of the beautiful Spitfire after the second flight of a new season.
- Launching a glider with the receiver power switch in the off position. This is often also accompanied by damage to the transmitter control sticks from the extreme movement and pressure applied in a vain attempt to turn the glider during ascent.
- One or more of the controls reversed (as with the Spitfire). This usually results in a short and tragic flight.
- Fuel mixture set too lean. This often results in flameout and emergency landing shortly after takeoff.
- Minimum idle set too high. This could cause the airplane to overshoot the landing approach and run off the runway into rocks or fenceposts.
- Antenna collapsed. This also makes for some very exaggerated actions on the part of the pilot in trying to find a good signal. Keep the antenna extended; tape the antenna base to the fuselage if necessary.
- If a wing is held in place only by rubber bands (two bands will not hold a wing in place for flight for very long), the wing will soon separate from the fuselage, leaving the fuselage on a parabolic trajectory to the ground. The first hint here may be that the model becomes hard to trim after takeoff. If you find a model hard to trim, cut the throttle, slow the aircraft down, and get it on the ground quickly.
Many of the errors that I have seen and you may have observed were caused by not checking some aspect of the model to ensure it was ready for flight. These can be found and misfortune prevented.
The sidebar shows a checklist I've developed for my own use. It has helped me catch and correct errors and failures during my preflight that could have cost me a model. I hope you find it useful. Good flying!
Don Brooks 900 Bower Dr. Idaho Falls ID 83404
Preflight Checklist
- Get frequency pin first thing.
- Bolts tight: engine/muffler/wheel collars/wing.
- Battery charge (charged within last 24 hours, or do voltmeter check).
- Radio range check (antenna down at 30 paces).
- Rudder/elevator operation (binding/travel/direction).
- Engine/nose gear/aileron operation (binding/travel/direction).
- Trims/controls at neutral.
- Check control surface play.
- Start/set/check engine mixture for full throttle/idle (check full throttle, nose up; reliable idle and full throttle).
- Fuel flow (no bubbles) and control surface flutter at full power.
- Kill engine with throttle trim.
- Restart engine.
- Extend radio antenna.
Transcribed from original scans by AI. Minor OCR errors may remain.
