Are there any airplanes with variable tail geometries (variable in flight)? I'm envisioning smaller than normal horizontal/vertical stabilizers for reduced drag during normal flight, but with the ability for the stabilizers to move away from the fuselage during extreme/emergency maneuvering (to apply more leverage for the same airfoil shape).
I didn't realize it at the time but my dear old Dad mentored me in aviation from a really young age. He was an Aviation Machinist Mate dating from 1940. He had seen a lot...
One pithy quote I've always recalled:
"Airshows are killers."
My apologies to weasels.
Yeah, the F-16 now has Auto GCAS (Ground Collision Avoidance System) in the versions of the jet with the digital FLCS. Works like a champ, and saved several lives in the first year of fielding, and more after that. Might not work well at the altitudes flown on the race circuit. The system intervenes when it calculates the jet is 2 seconds from hitting the ground, and the gear is not down. But just like Narcan, AGCAS is not a fix against poor judgment. Furthermore, the system could not be installed in a Jet like the L-29 because the L-29 does not have a digital flight control system. The AGCAS overrides pilot input, and provides commands to the FLCS to roll and pull away from the ground. It uses a digital terrain model in system memory, and compares the current flight vector to the terrain map.Originally Posted by Suvorov
I don’t know squat about Reno Air Racing. But I do know at low altitude the time to impact is very short. I used to teach that when on a low-level (500 feet, 480+ kts) and in a turn, only turn. Nothing else, just fly the jet. Don’t mess with the radar or sensors, don’t check 6, just fly. The time to impact is short, the potential for over-bank makes the time to impact very short. As a pilot steps down from 500 to 300 to 100 feet, the ability to perform other tasks disappears. All you can do is fly and avoid the terrain. On the IP to target let, we typically accelerate to 540 or 600kts, so the time to react just gets shorter.
In the grainy video it appears (big assumption on my part) the pilot misprioritized cutting inside the pylon with flying, and reversed his turn/bank in error. I would have relaxed the G, and unloaded the jet while keeping the bank. Instead it appears the pilot reversed his turn, developed too many angles (mis-aligned his fuselage) compared to his opponent and the course line, than snapped his jet back into a left turn (to save the race) and snatched the stick and put a lot of Gs on the jet. Straight wing jets have a very height G onset rate (T-37, F-18A) and a pilot can GLOC with a sudden pull. If he GLOCed at a high bank, and close to the ground, there is little option at that point. A full GLOC lasts about 12 seconds, with another 12 seconds of partial incapacitation after that. If the ground is closer that 24 seconds, odds are the jet will impact before the pilot can think to eject or correct his flight path.
Flying is very unforgiving of error, and low altitude racing is probably the most extreme form of unforgiving flight. One small mistake, miscalculation, misperception, or mechanical malfunction can cause a problem that becomes fatal. I feel sorry for the pilot’s family, and the friends he left behind. But he died doing something he loved to do, and I can’t fault him for that. Rest In Peace.
"Government is not reason, it is not eloquence, it is force; like fire, a troublesome servant and a fearful master"
Lots of truth and good information in the above.
Thanks for posting.
Working diligently to enlarge my group size.
None that I’m aware of. One might be able to argue that variable geometry wing aircraft like the F-14 and F-111 that effectively become delta wing airplanes are modifying their stabilizers but I know that isn’t what you are asking.
One airplane I know of that approaches what you are asking is the MD-11. The MD-11 was essentially a stretched DC-10 but has a horizontal stabilizer that is MUCH smaller than the DC-10. The primary reason it was designed this way was to reduce drag and allow the MD-11 to have the range and better fuel consumption that were required for airliners of it’s generation (777, A330/340). This smaller stabilizer had the negative effect of reducing the airplane’s pitch authority. To counter act this, the airplane had a much narrower limit to its allowable center of gravity which made it more pitch neutral (a normal airplane will be designed to want to have its CG forward so that it will tend to pitch down) reducing in better pitch authority but less stability. To help balance the airplane and keep CG in the desired range, fuel would be transferred both on the ground and in flight to the horizontal stabilizer (transfer of fuel to balance airplanes is not that rare, other airplanes such as Concord did it too). Because the airplane had less longitudinal/pitch stability, the flight controls were augmented with a system (called the Longitudinal Stability Augmentation System) that would apply stabilizer inputs to make the airplane behave line a normal “well behaved airplane.”
While in the real world this design worked, and the MD-11 eventually met its design requirements, the MD-11 suffered a higher accident rate than its contemporaries did. While the stabilizer was able to compensate for its size in normal situations, it proved to lack the needed authority in more extreme situations. I know of at least 4 instances when lack of pitch control following a bounced landing resulted in oscillations which would end up with the aircraft flipping on its back with catastrophic results. Boeing has made many updates to the flight software on the airplane and that along with training to go around instead of trying to save a bounced landing has helped improve the safety of the jet.
Hope this helps in some way but if not it at least gave me a chance to talk about one of my favorite planes……
The main reason they were so short lived at Delta...
No shortage of smoldering MD11 pics on the web.
“Somewhat” humorous story in the one that balled up in EWR. Story goes there were two guys jumseating into work (different airline) on it. I can see it now...after they came to a screeching halt inverted, I’m willing to bet at least one of them popped their harness and said “Well thanks for the ride to work guys, if you don’t mind, I’ll hop out now. Showtime is in 20 minutes.”
😁
Working diligently to enlarge my group size.
The Captain on the EWR crash was in my initial class in Artisia. Nice guy and had a hell of a story to tell. FedEx, NTSB , and ALPO (surprise surprise) threw him under the bus and he ended up at Polar. Saw him in requal right before he retired.
Interesting.
Have to have a scapegoat. So glad I’m out of the Herndon business.
I heard it could be a real handful given the right conditions.
Working diligently to enlarge my group size.
True, but as for the ones who actually fly, Dunning-Kruger gets trumped by Darwin.
When I was on the original Avsig, one year, we lost two guys in two crashes who were going to OSH.
If we have to march off into the next world, let us walk there on the bodies of our enemies.
If you spent any time at experimental, then for sure. I was a college intern and this job basically changed my life. I have exactly 1 picture from my time at Beech. We had the camouflaged Thornton T-38 (pictured below) come out for our Vd testing and we took a group picture. I'll find it and send it to you in IM, I am sure you will recognize a bunch of the pilots.
A patch from those days:
It is!!!
I interviewed at Eclipse Aviation (ABQ) in the 2004 timeframe and a propulsion flight test guy from Beech had me in his office for an hour. That same picture I am talking about with the T-38 was ON HIS OFFICE WALL. I couldn't believe it, sitting there for an interview and I'm in one of his wall pictures. That portion of the interview turned into a BS session and I thought for sure I had this. Even more unbelievable... I didn't get the job (last interviewer of the day ate my lunch, some VP). At the time I was bummed, but they went bankrupt 4 years later so I was probably lucky.
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