The airplane we've been dealing with at work made the test flight this afternoon. You know you've done a good job when a factory test pilot gets off the airplane and tells you, "That airplane flies really nice." Remember, this is a production test pilot who probably last flew this particular airplane when it was originally built and certified about 12 years ago...
The back story is this--Learjets require a major inspection every 12 years and another one every 12,000 flight hours. This is in addition to other phase/time inspections on a more frequent basis (6 months, 12 months, etc.). The 12-year, though, is a biggie. The interior gets removed, the antennas get removed, even the instruments and instrument panel gets pulled out, all so the airframe can be X-Rayed and tested in other ways (eddy current, ultrasound, etc.). Then, once you know what you have, you effect repairs. During this inspection, you'll find cracked windows, cracked structural members, corrosion, and all sorts of other issues that need to be dealt with. There are other time items to do--certify the air data computers so the altitude and airspeed readouts are correct, calibrate the fuel quantity system, check the Emergency Locater Transmitter (ELT), service the emergency batteries--you get the picture. You also remove the leading edge panels on the wing. Now, a Learjet is a high-performance aircraft, and how the air flows over the wing is very important. Removing even two adjacent screws from the leading edge panel, if you read the maintenance manual, requires a test flight along the lines of what we had done today, since you can change the flight--and stall--characteristics of the airplane drastically. Even having too much sealant on the panel joints has been known to adversely affect the stall of a Learjet, so it is important that the work gets done properly. That being said, you can only do so much on the ground to certify the systems. The only way to know how the airplane will perform in flight is to fly it.
What's a stall? Well, in aerodynamic terms, it is when the airflow over the wing gets so disturbed that the wing stops generating lift--in other words, the wing is no longer flying. You enter a stall by pitching the nose up, pulling the power back, the airplane may (or may not--depends on the airframe) start to buffet and growl at you, the stick shaker (a little motor and eccentric weight that makes the control yoke vibrate) activates, lights flash, and...then it seems like the sky has literally dropped you. The nose drops, and if all goes well, the airplane maintains a level flight attitude. As the airplane regains forward motion, the wing starts flying again. Easy, right? Well, some airplanes behave as they should. But sometimes, you'll have one that snaps a wing down into a roll after the stall. Or enters a spin. Bad news. That means that something needs to be re-adjusted, re-worked, or re-rigged, and the airplane needs to be flown again. Fortunately, today's flight went extremely well, and we're about ready to deliver it to the owner so he can put it back into service.
Not bad for three months' work.
On the miniature aviation front, progress is being made on the 1/72 scale FineMolds Ki-100b, and, just as a quickie for comparison, I started a 1/72 Hasegawa Ki-61 to show the differences between the radial-engined Ki-100 and the in-line Ki-61. The two of them should make a nice display--the Ki-61 is being built strictly out of the box (I didn't even add a stick, since you can't see a whole lot once the canopy is stuck in place) with kit decals--more than likely, I'll do MAJ Kobayashi's airplane.
The StuG IV is progressing, too. I've finished the Zimmerit and have to squirt some flat black paint under the engine deck so I can button that area up. The fenders are on, I hope to start putting the gun and fighting compartment together before too long. For this one, I decided to go OOB (well, OOB plus the Zimmerit) and concentrate my efforts on the finish, since I can rarely get a convincing finish on an armor piece.
The other projects should pick up, too. I'll give you updates and photos as I'm able.
Thanks for reading. Be good to one another, and I bid you Peace.
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