I was waiting for the final line of the story: after all that work, he takes it out for a flight and promptly crashes it. But no. That was a relief. He’s obviously a talented builder and flyer. And lucky.
IME, making flying models (I did mostly model rockets, not planes) is a heart-breaking hobby. Hours and hours of work building a beautiful model, only to damage or destroy it.
But the risk of flying it is all part of the process. I never built a model rocket I didn’t fly. None of the ones I still have is unscathed.
The most successful model rocket I ever built had exactly one flight. It flew too well. I lost it in cloud deck I was sure it wouldn’t reach, but it outdid itself and punched a hole straight to heaven, and I never saw it again.
You started one on Model Rockets–but haven’t updated it in 19 years:
For example:
I still have some unbuilt kits lying about. There’s a balsa-nosed Alpha or two. These came with decals, but the ones pictured in the catalogue didn’t have them. Nope, white body, red nosecone, one black fin and a black stripe.
Never did. Never got around to it, and then I got married.
‘Model Rockets’ is only about model rockets though. I was thinking Flying Models to cover model rockets, Guillow’s, Sterling, etc. balsa models, r/c models, etc. (But I wouldn’t include drones because they’re not in the spirit of the others.)
I didn’t know Bentley made one. I assumed everybody used a Le Rhone or some variant. Instead of trying to build bigger ones they should have gone to an inline twin engine design to counter the rotational mass.
How come? They already had the Airco DH2 pusher. Stick a rotary in front and back and the 2 of them would cancel out the negative rotational force that made them so hard to fly.
What does it mean when it is said some plane takes X-amount of maintenance hours per flight hour?
I was watching something about the delivery of F-16 fighter jets to Ukraine and, while encouraging, they noted it is not as simple as it seems on the surface. Apart from a long time to train the pilots to use them and not nearly as many as are needed to be really useful, they also noted that each F-16 takes 17 hours of maintenance per flight hour.
Does that mean if a single flight takes (say) three hours the plane is then in the shop for 51 hours?
That seems nuts. Even if you say five people worked on the plane at the same time it is still 10 hours, minimum, of work on the plane after every flight. Multiplied by the number of planes in the squadron.
I get these are complex machines and, like any machine, need maintenance. But are they really so fragile?
ETA: This may have been addressed before on this board but I didn’t find it (I didn’t look very hard though).
I’ve always assumed it’s an average. GA airplanes have to be maintained… but not after every flight. A typical GA piston engine has a TBO of 2,000 hours. One cite I found in a quick search says it can take up to three weeks to overhaul an engine. At eight hours per day, and 15 days, that’s 120 hours of specific maintenance for 2,000 of flight. I think that comes out to about four minutes of overhaul per hour of flight. If you count refuelling as ‘maintenance’, that adds a little time. Then you have oil replenishment and changes, spark plugs, instruments and avionics, annual and possibly 100-hour inspections, etc. that add to maintenance hours. But GA airplanes are pretty simple, so maintenance hours per flight hours are pretty low. On something like a fighter jet, which is much more complex and have to have mission-readiness maintenance, I can see the average hours being high.
It’s likely a function of hrs flown. The more flown the less hrs of maintenance per hr.
I’ve known private owners who only made 1 flight a year because of an unfortunate string of maintenance items. That could easily have been a 100 maintenance hr per flight hour year.
It’s the total maintenance burden divided by operating hours. So if a ABC gizmo breaks and needs to be replaced with a spare, that might take 30 man-minutes out on the flight line. But some other shop on the base will then spend 5 hours troubleshooting and repairing the ABC gizmo before putting it back on the shelves in the warehouse as a good spare. All 5 hours of that repair is part of the total maintenance burden, not just the 15 minutes.
Back in the days of the F-4, the mean time between failures of the radar was about 6 hours. So two flights then it needed work. Difficult, painstaking, highly skilled analog electronics and discrete components work.
When I was doing the F-16 we actually had pretty high reliability. Once in awhile one or another black box acted up, but I probably made a writeup one in 20 flights. The problem was that when that one write up occurred, replacing the box on the jet was the easy part. It was fixing the box in the shop that took lots of worker time. Plus of course the sometimes experience of swapping out the box you thought it was and that not solving the problem. So then you swap something else, etc. All those labor hours are getting spent and you’re not getting closer to the actual fix yet.
A majorly disproportionate number of hours goes to the unexpected faults that aren’t in the diagnostic manual. Like a flaky spot somewhere in a wire or connection, rather than a whole box that’s failing BIT or bench testing. Vast hours can be spent chasing “gremlins”.
And, like they said, the routine maintenance of inspections, tire replacements, refilling hydraulics, etc., lubing the umpteen moving parts, etc. No one job is huge, but there are many.
737 cowl latches are an ongoing problem. There are 3 that hold the fan cowling section closed. They’re along the general underside of the front part of the engine. They don’t generally fail. But they are difficult to close, are difficult to verify that they’re closed, and the right engine is harder for both of those steps than is the left.
Southwest has an especial handicap which is why this keeps happening to them. Back 30+ years ago in the early Kelleher days, they got an exemption to skip the pilot preflight. That wastes too much time Herb said, and FAA listened to their darling of the day.
Somewhere along the way SWA, exactly like everybody else, eliminated having a mechanic look at the airplane between flights. But the difference for SWA is that without mechanics or pilots looking at these things, there’s nobody left with real skin in the game and real training. Darn near every 737 driver of any years’ experience has found an open latch on preflight. I sure have. By design, SWA finds theirs during takeoff.
There was an AD to address this latching problem about 10-15 years ago after another spate of these events. The big fix? Paint the handle of the latch orange so it’s easier to see if it’s not flush with the cowling as it should be. But you really need to hunker down into a baseball catcher’s posture to see the damn things. With so many older A&Ps and pilots, that is less easy than it once was.
Actually, hunkering down is easy enough; it’s getting back up that’s hard.
Great find. The article is about the problem, and their responses, on all aircraft and engine types. Certainly including the CFM-56 on the traditional A320s.
Back in the day when I was doing a lot of traveling, the food in Air Canada business class was always excellent, especially on longer flights, and always consisted of beautifully presented multiple courses. But that was in the late 80s to early 90s. Things may have become enshittified since then.
