by Alfred Scott
This article appeared in the September 1989 Falco Builders Letter.
The 22nd Sequoia Falco broke ground on June 27 from Grants Pass, Oregon. The proud builder and pilot is Rex Hume who built the plane over an eight-year span. Rex is an A&P mechanic, who already had 39 years of experience at that job when he bought the Falco plans in September 1980, and he had also rebuilt a lovely old Harlow PJC-2.
At that time he was living near San Diego, but he moved to Williams, Oregon, four years later and after doing much work on the airplane. Rex likes building things, and he built the plane from plans, although he bought this-and-that from us. The airplane has a 180 hp O-360-A1A with an aluminum cowling and lightweight B&C starter. The empty weight is 1,251 lbs with a CG of 63.5".
The cowling by itself is enough to make you stand in awe of Rex's handiwork. There are precious few people who can make aluminum take such bends. It's work that requires an incredible amount of skill with a hammer, working the aluminum over a wooden mold and stretching the aluminum by pounding it over a sandbag. This is the way many exotic Italian cars are built, and it's certainly within the ability of a lone craftsman, but very unusual to see. Rex says, with pride, that "the only fiberglass on the outside of the aircraft is the main gear wheel well doors." That's really rather remarkable when you look at the lovely shape and smooth curves on the bottom of the cowling and carburetor air scoop.
It's also unusual to see in a plans-built Falco such a faithful rendition of our instrument panel, throttle quadrant, glareshield, seats, etc. Many homebuilders branch off on their own when it comes to such things as the panel design, but Rex has plainly drilled every hole in the exact location called out on the drawing. The stick grips and throttle quadrant knobs are a light-colored wood coated with a clear finish.
The airplane is painted white. The instrument panel and interior is all light grey and is very simple and attractive. N660RH is equipped with a single King navcom, transponder and Apollo loran. Rex is certifying the airplane for night and instrument flying.
Rex reports that he trailered the Falco to the Grants Pass airport on May 5th, assembled all parts, did the weight and balance. This made Grants Pass airport the first airport in the world to have two homebuilt Falcos based there, since Ray Purkiser is also at the field. Rex and Ray are friends and on May 12th, Ray put Rex in the left seat of his Falco and Rex made his first takeoff and landing in 28 years. Rex has about 1,400 hours in Stinson Voyagers, Monocoupes, SNJs, Stearmans, Twin Beech, etc.
The FAA inspector arrived on June 12, and signed the plane off. Rex reports, "On June 19th, I was signed off on my bienniel flight review in a Cessna 172 after less than three hours dual. I made four high speed taxi runs up to about 55 knots in my Falco before the first flight a couple of days later. Everything went well with the first flight of 50 minutes, and Ray Purkiser flew chase for me on the first flight with a passenger and video camera. I didn't retract the gear until the second flight. The aircraft trues out at 205 mph at 6000 feet, 23"/2300 rpm. Climbs out at 1800-2000 ft per minute."
Rex now has over ten hours and thirteen flights on the airplane. Rex reports "The landings have proved to be the easiest part. The plane is so easy to land, and it jumps off the ground before I get full throttle if I don't watch it." Rex reports a number of minor teething problems with the plane. The nose gear wheel well doors have given him some difficulty. He said "the gear will not fully retract without popping the circuit breaker, so I took them off-will remake them later with a continuous piano hinge and a different spring."
"I still have to use the manual gear crank to down position to compress the springs. The motor does not coast. Will play with that later. I've had two engine problems. One was an oil leak at the O.D. of the crankshaft seal, so I removed the prop and seal, and sealed with Tite-Seal. Have two hours since, and it looks okay. The other problem is the oil pressure transmitter. It fluctuated from 70 psi down into the yellow band periodically after several minutes of flight. I installed a Stewart-Warner system as a backup and bled pressure hoses to the senders. It helped a great deal but still fluctuated occasionally."
The oil pressure transducer that we use is made by our instrument supplier, Rochester Instruments. Rochester makes the engine instrument clusters for Mooney, Piper, Beech, Cessna, and others. For years they used the inexpensive oil pressure sender that you still see sold through catalogs. This sender is a marine/automotive unit that has a rheostat connected to some sort of pressure device (diaphragm or Bourdon tube). Since the berylium copper wiper of the rheostat rarely moved-remember oil pressure rarely changes-the engine vibration would cause the wiper to cut through the thin copper wires of the coil. The wipers cut through the coils with such frequency that they usually didn't even last through the warranty period and Rochester said that they were tired of replacing the things. As a result, they made their own sender, which uses a potentiometer instead of a rheostat.
Rex's problem with the fluctuations in the oil pressure indications sounds like a loose electrical connection to me. I can't imagine what in the oil pressure transducer mechanism would create such a result. One thing you absolutely do not want to do is to hook up one of the rheostat-type senders to our instrument cluster. The resistances are dramatically different, and it will destroy the gauge.
Rex Hume and Ray Purkiser taxi in after the first flight.
One thing that I would like to talk about here, as gently as I can and without being unduly critical. Rex said he was following our flight test guide "by the book" in his testing of the airplane. The flight test guide gives you an extremely complete check list for the final inspections and then a logical sequence for the testing of the airplane. These things, I think, dramatically reduce the risk of something going wrong on the first flight. I know that prior to the flight test guide, we had a very high incidence of problems which were discovered in the air-clogged fuel vents, governors that worked incorrectly, oil leaks, etc.-that should have been discovered before the wheels left the ground. The inspection procedure seems to have eliminated that sort of thing.
The flight test sequence of engine ground runs, taxi tests, controls effectiveness tests and flight tests also reduces the risk. But none of these things eliminates the risk of something going wrong; after all, it is a flight test of an airplane that has never flown before. One thing that was not at all "by the book" was who flew the plane.
It's not a widely publicized statistic, but each year roughly 10 to 20 percent of all fatalities in homebuilt aircraft occur on the very first flight. There are any number of things that cause problems-fuel system problems are very high on the list-and the pilot fails to successfully get the plane back on the runway. There is a very repeatible pattern to the fatalities-the builder does the first flight, and the builder let his flying skills get rusty during the course of building the plane.
I don't mean to jump on Rex; he's got a lot of time in some difficult airplanes; he read our manual and made his own decision. That's fine, but I hope that the success that we are having in reducing problems on flight testing does not lull anyone into complacency. We'd like to see the test pilot be someone who is extremely overqualified. Let's face it, if nothing goes wrong on the first flight, almost anyone can do it, but you should be prepared for the worst. So when the airplane proves to be barely controllable and suffers an electrical fire and engine failure on takeoff, we'd like to see the test pilot be someone who can put it back on the runway with aplomb. For most of us that pilot is someone else.