One strike, you're out
Dave Gee [email protected]
A genuine FF accident? Yup — I heard a report of just such a thing, and it was pretty serious.
If you’ve ever attended a major FF contest, you’ve seen and admired the big gas aircraft that take off vertically and roar up into the sky. A limited-power runtime means the engines are powerful and tuned to their peak. The pilots make it look easy, but it’s not. Trimming one of these airplanes can be a challenge.
An experienced builder was recently tweaking his model. He started the engine and released the airplane straight up as usual. The aircraft had other ideas and made a sharp loop. The pilot was unable to get out of the way as the airplane zoomed in from behind him at full speed. It sounds funny, and maybe it will be in a few years, but for now the results were a serious injury and immediate evacuation to the emergency room.
Not only did the impact of the model itself cause harm, but the spinning propeller caused serious damage. After many stitches, the modeler faces a painful and inconvenient recovery. A spinal impact could have been much worse, of course, but this was bad enough.
This episode occurred at a well-organized AMA-sanctioned meet, and the situation was skillfully handled. First aid was immediately available. The pilot’s friends took care of him and his gear. This contest was run by experienced, thoughtful people who had planned for emergencies. Their preparation paid off in this case. Being ready for trouble might not prevent an accident, but it sure can keep bad things to a minimum.
Table That Motion
Speaking of minimums, some of us have to get along without a deluxe hobby workshop. More than a few models have been built in living rooms. A reader wrote to me about an exciting moment that happened while he finished an airplane on his coffee table.
“I had just spent the day building a 3-D foamie and all I needed to do was set the trim and the control throws and the plane would be ready to take to the field. The prop was on the motor shaft and I had verified that the thrust was toward the tail, and since I was only adjusting trim, this didn’t seem to be much of a risk. I put the plane on a table in the living room and grabbed the manual so I could check for the proper control throws.
“One of the first steps was to verify that all of the control surfaces moved in the proper direction, and as it turned out, the rudder was reversed, so I quickly went into the settings and selected the servo reverse menu. A list appeared of all of the controls — throttle, aileron, rudder, elevator, etc. — and there were two buttons you could press: one would reverse the servo, and the other would select the next control on the list. Guess which button I pressed?
“The plane that was quietly parked suddenly had the throttle servo reversed, so instead of no throttle, it was now set to full throttle. The plane took off immediately and made it about 3 feet before impacting our foosball table. I was fortunate since my immediate response after pressing the wrong button was to press it again, and immediately the throttle went back to normal. I got up to inspect the plane and the game table.
“Fortunately, the plane was fine, but there was a nice, fresh nick in the foosball table where either the metal spinner or the blade hit it. My wife and kids, having heard the noise, arrived quickly to investigate the commotion.
“I learned that any powered-up electric plane is just a button click or a stick bump away from going airborne. Taking a minute to remove the prop when adjusting any servo directions or throws is a good precaution. For transmitter manufacturers, I might suggest that reversing the throttle channel should include an ‘are you sure?’ dialog to reduce the chance of this type of accident.”
This is another example of the danger of mixing incompatible hobbies. How many times have we heard that RC airplanes and foosball don’t go together? Of course, a nice piece of plywood could convert that soccer table into a workbench, complete with funny knobs sticking out. Just sayin’.
Feel the Burn
Another pair of things that don't go well together is fingers and hot surfaces. A reader sent me this story.
"I had a GWS Slow Stick that originally had a brushed motor. I'm always looking for ways to make my planes go faster, so of course the brushed motor had to go. I didn't want to buy a new motor for the Slow Stick, so I looked in my parts box and found a brushless motor from a crashed model. The salvaged motor was installed and given an 8 x 5 prop.
"When the Slow Stick was test-flown, I heard a weird screech-like noise. A few seconds later, there was a little smoke coming out of the motor, then it locked up. I had to make a dead-stick landing.
"When I went to get the model, there were sparks coming out of the motor, so I quickly unplugged it and got away from it. A minute or two later, both the motor and ESC caught on fire. A friend helped me put the fire out and we both stepped away to let it cool. After about five minutes we went back to get it. As I picked it up, I accidentally touched the motor for a split second and got a terrible burn and a blister on the spot that touched the motor.
"Afterward I realized I had over-propped it, which caused the motor to pull too many amps, lock up, then catch on fire. Now I only use motors that match the factory recommendations for a given model, and I check the prop specs to make sure everything is compatible."
Mystery Airplane
When you enlarge the Presto to a 16-inch wingspan, it becomes a fine Bostonian with a quaint “period” style. The mystery airplane prize this month is digital plans for an aircraft with a modernized structure. You can see a video of my prototype in flight on YouTube. The link is listed in “Sources.”
The mystery airplane in the photo was produced by a well-known modeler who has become even more famous as a designer of record-breaking, full-scale aircraft. His company is known for using aeromodeling techniques in its amazing line of products.
Email me the name of the aircraft in the cropped photo (the white one with round windows) and you’ll get plans for the Presto Bostonian, even if you guess incorrectly.
SOURCES:
- Presto Bostonian YouTube video: http://youtu.be/HHkltw3XbD0
Transcribed from original scans by AI. Minor OCR errors may remain.
