We're the Military and Airpower Guys of Jonah Goldberg of National Review Online + a stray we found wandering around looking lost. All original material JHD, BHD, JR, WT, and KA 2003-2010 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html Fri, 06 Jan 2012 18:22:36 Z Movable Type 4.12 en Copyright 2012 http://www.rssboard.org/rss-specification http://www.thedonovan.com/archives/2009/02/update_us_air_1.html http://www.thedonovan.com/archives/2009/02/update_us_air_1.html Wed, 04 Feb 2009 15:09:38 -0600
The screens were primarily intended to prevent FOAD from Russian runways and probably not sized to counter geese. The FOAD would have been thrown up by the nosewheel, and thus the screens closed the inlet when the wheel was on the ground. Apparently the transition from ducts closed to ducts open had little effect on the takeoff as sensed by the pilot. From the exterior observer, the operation was very quick.

No, the screen would not stop a goose.

Cheers]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83935 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83935 Thu, 05 Feb 2009 17:06:32 -0600
Maybe we just need to paint the airplanes to look like birds of prey, like those hawk sillhouettes you're supposed to put on picture windows to keep the birds from smacking into them...
]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83919 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83919 Thu, 05 Feb 2009 12:17:22 -0600
I was thinking more along the lines of "Redneck Airways..."]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83904 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83904 Thu, 05 Feb 2009 09:29:50 -0600
Two words vis-a-vis deer sirens: "Doppler effect."

NDSteve,

My huntin' friends tell me a goose makes a hell of a "thump" when they hit the deck after taking on excessive buckshot. The swans may be bigger, but the geese are WAY big enough to hammer an engine. (US1549=QED).]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83901 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83901 Thu, 05 Feb 2009 09:01:15 -0600 Never mind .... just read Josh's comments and the responses more carefully. Sorry. http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83900 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83900 Thu, 05 Feb 2009 08:41:52 -0600 Would some kind of wire mesh over the air intakes create so much drag, reduce lift, or otherwise alter flight characteristics to make that idea unfeasable? http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83899 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83899 Thu, 05 Feb 2009 08:38:29 -0600
Bill O'Reilly has a problem, he gets an idea in his head and you can't knock it out with a baseball bat. Now, sometimes that's a good thing but not always. O'Reilly has a vendetta againist GE and its chairman Jeffrey Immelt and anything he can pelt them with he will.

As for geese, they're small potatoes. there is a small lake (pond really, but the city owns it so it's a lake) here where geese always stop by and they are sometimes joined by trumpeter swans. I went out and took a picture there last week and I was struck by how much larger the swans were than the geese. 

http://www.nevadadailymail.com/story/1497790.html

BTW my dad had a saying about cr*p through a goose and I never understood why their digestive systems would be any speedier than any others but after seeing all those geese I can at least attest to the AMOUNT they produce.

]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83898 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83898 Thu, 05 Feb 2009 08:21:30 -0600
Turkey buzzards are the worst. They barf when they think they're being threatened, and remember what they *eat*...
]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83897 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83897 Thu, 05 Feb 2009 07:57:51 -0600 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83895 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83895 Thu, 05 Feb 2009 06:54:44 -0600
Can something be mounted on an aircraft to get these birds out of the way one way or the other?  Is it worth it to do that?  If it's really good it can pluck them and serve in flight. :D

Litigation really is the paralysis of our modern society.
]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83893 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83893 Thu, 05 Feb 2009 02:42:01 -0600 Anything big and heavy enough to be useful to deflect a flock of 4-lb geese is going to significantly impede airflow into the engine, Josh. The device would have to span two metres wide, with small enough apertures to screen or mash the incoming birds, and yet big enough holes to allow the engine to operate at a reasonable level of efficiency. And it must never shed parts of itself into the engine, either.

Hmmm the high-bypass turbofans popular these days certainly DO make it more of a problem.  What happened to the good old days with those good old noisy, smoky turbojets?

Plus the thing would be a magnet for ice, so it would have to be heated, and preheating air going into the engine also reduces its performance.

If it were in fact some kind of device utilizing metal cables, maybe you could just run electrical current right through them?  That wouldn't affect performance nearly as much as blowing hot bleed air all over them.

Personally I think the effort would be best invested in small chemical lasers to shoot the bastards down before they can get ingested. They are always flying without transponders and refusing ATC vectors anyway. Somebody ought to pull their ticket.

Damn straight!  But instead of lasers, why not mount a bunch of tiny little 3 inch long miniature AIM-9s by each engine?

]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83890 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83890 Thu, 05 Feb 2009 01:35:58 -0600 All my engineer buddies tell me stuff in front of the intake is basically a Bad Thing, regardless of its relative "density."

I'd tell ya that too, but then again, we'll also tell you that engineering is often a tradeoff between one Bad Thing or another.

As far as shock waves go, not that big a deal on something as slow as a commercial jet. [...] Ironically, being slow requires MORE power than at cruise so any obstruction to flow, no matter how minor, comes at great cost.

Yeah in this particular case I guess the shockwaves aren't really the issue so much as the problems with drag and turbulence on the airflow (since you want smooth airflow into the intake), although airspeed is more important here than engine power.

but anything in front of that big hole is looked on with extreme suspicion by engineer and pilot alike

Certainly true, which is why it's vital that any device be designed so that it's only "in front of the hole" on takeoff (and maybe landing), and then gets out of the way.

]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83887 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83887 Thu, 05 Feb 2009 00:50:40 -0600
Plus the thing would be a magnet for ice, so it would have to be heated, and preheating air going into the engine also reduces its performance.

Personally I think the effort would be best invested in small chemical lasers to shoot the bastards down before they can get ingested.  They are always flying without transponders and refusing ATC vectors anyway.  Somebody ought to pull their ticket.
]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83886 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83886 Thu, 05 Feb 2009 00:50:17 -0600
All my engineer buddies tell me stuff in front of the intake is basically a Bad Thing, regardless of its relative "density."

As far as shock waves go, not that big a deal on something as slow as a commercial jet. "Slow" is relative, but a 'Bus motors around at something like .78 Mach and very much slower in the departure/arrival pattern (I know...they force me to slow down in the pattern all the time). Ironically, being slow requires MORE power than at cruise so any obstruction to flow, no matter how minor, comes at great cost. 

Now, if we're talking Mach 3+, or even transonic/low supersonic, yeah, now you're getting into variable geometry intake ramps (F-15) and/or shock cones (SR-71). Take a close look at the spinners on a commercial jet next time you get a chance...not much "pointyness" there 'cause it isn't necessary, but anything in front of that big hole is looked on with extreme suspicion by engineer and pilot alike.]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83885 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83885 Thu, 05 Feb 2009 00:32:08 -0600
I guess my basic idea I'm trying to describe is not "armor" so much as an attempt to deploy some sort of "screen"-like device over the intake that, at relatively low velocities, where air can be approximated as an extremely low-viscosity fluid (unlike cruising velocities, where air begins to approximate a high-viscosity fluid, AND you get into problems with shockwaves and such), will not significantly hinder airflow, while at the same time (mostly depending on collision speed), either deflecting or "chopping up" any flying animals or other objects that might be in the air (stray parachuters, weather balloons, whatever) before they hit the turbine blades.  It's not so much an apparatus to completely shield the intake, as that would be incompatible with achieving takeoff thrust, as it is an attempt to mitigate the damage of a birdstrike or something like that.
]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83877 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83877 Wed, 04 Feb 2009 22:14:17 -0600 In one sentence, the cause was enemy action by illegal-immigrant Canadian terrorists. I have been trying for some time to get my (probably ex-by-now) Sweety to stop feeding the damned Canada geese which hang out at the pond on her property. They crowd out the native Georgia birds, crap everywhere, and just won't shut up. Every time I suggested that she had them tame enough that we could get them dead and into the oven without making shotgun noises, she looked at me all funny-like. http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83874 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83874 Wed, 04 Feb 2009 20:45:47 -0600
Alas, the mass flow requirement for today's commercial engines is too great to allow for "armor" in front of the intakes for takeoff. 

Granted, there have been designs like the one you refer to but they were conceived for scenarios commercial jets would never face, like landing on/taking off from unimproved fields. Also, I'm not so sure the MiG or Sukhoi designs were more than a "good idea." If I remember correctly, the main intake opens during takeoff on nose strut extension (I think) and closes on main gear touchdown on landing and dorsal intake opens above the now-closed primary intake while the latter is closed. Even a Russian fighter, with its HUGE brute-force engineered stainless steel engines-from-hell would have major problems with thrust requirements on takeoff with this configuration because those requirements would dwarf anything required when recovering. The departing jet is loaded for combat (fuel, ordnance, etc.) and it is trying to overcome gravity, not using it to return to earth at relatively low power settings.

Finally, the bird strike risk does not overshadow the loss-of-thrust risk imposed by a however-temporary obstruction over the intake. Then there's ice buildup on something like that on a winter day while taxiing to the runway, etc., etc., etc.

In short, it sounds good, but it's way too impractical.]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83866 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83866 Wed, 04 Feb 2009 17:17:34 -0600
This does make me wonder, though...could there be some way to fit podded turbofans with some kind of anti-FOD device for takeoffs and landings?  I mean the MiG-29 has some kind of variable-geometry intake nacelles that change the airflow pattern for takeoffs on unimproved airstrips to avoid ingestion of crap on the ground, although I don't know if it helps any for avoiding birdstrikes, and the engine layout is very different, as they're buried in those under-fuselage nacelles.

I'm thinking maybe some kind of system with wires set into the outer rim of the intake, with one end of each wire fixed and the other on a little roller, so they make a web pattern when extended and then at a few thousand feet the pilot hits the switch and they retract back into the rim...
]]> http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83864 http://www.thedonovan.com/archives/2009/02/update_us_air_1.html#comment-83864 Wed, 04 Feb 2009 16:43:04 -0600