Nuclear Deterrence & Massive Retaliation

[XBe02Drvr]

. I go on engine runs on turboprops on a nightly basis tho.

I never got to do that. Got plenty of practice taping the instrumentation umbilical to the wing, fuselage, and emergency exit while the engine run guys (top of the shop pecking order) stood around and kibitzed. As a mechanic with a pilot's license, I was an alien Intruder in their hard core blue collar culture, and never got to do any of the "good stuff". I did get plenty of practice at tires, brakes, lav dumps, daily walk arounds, outdoor lamp replacements, and towing with an open tug in wintertime.
I haven't seen an ATR or a Dash in years. All the service in these parts is Embraers, Canadairs, A320s, and the occasional 73. The ignorami flying public refer to anything with a prop on it as a "piston pounder" and protest loudly if asked to board one.
Cheers,
Wes

 

[Zipper730]

The U-2's stall speed being 94 knots sounds very suspicious: I'd figured they'd be a bit lower.

 

[XBe02Drvr]

The U-2's stall speed being 94 knots sounds very suspicious: I'd figured they'd be a bit lower.

As gliders go, it was a "heavy jet". If you're going to 70,000 feet and flying at jet speeds, you're probably going to want a different airfoil than what a Schweitzer 2-32 uses.

 

[Zipper730]

As gliders go, it was a "heavy jet". If you're going to 70,000 feet and flying at jet speeds, you're probably going to want a different airfoil than what a Schweitzer 2-32 uses.

Yeah, but I've seen footage of it landing on a carrier (there was a proposal of using a U-2 off a carrier deck -- as completely nuts as that sounds) deck. It appeared to be moving greatly slower than an F-14.

Usually landing speed is 1.15 - 1.3 times the stall-speed for a carrier approach, and if 135 is the approach speed for an F-14, then you'd 103.8 - 117.4 knots. This thing was coming in pretty slow in comparison.

 

[XBe02Drvr]

Usually landing speed is 1.15 - 1.3 times the stall-speed for a carrier approach, and if 135 is the approach speed for an F-14, then you'd 103.8 - 117.4 knots.

I might suggest your qualifications for making eyeball estimates of approach speeds might be a little thin? It takes an LSO thousands of hours of training and flying to do that. There are too many variables of wind, viewing angle, optical illusions, etc when viewing onboard, not to mention the additional distortions of lenses and resolution, and time lapse that video can introduce, to put much faith in that.
Squids are aided somewhat in that call by reading the approach indexer lights on the nose gear doors of their aircraft on approach. These are triggered by AOA sensors and display to all observers Fast, Onspeed, and Slow conditions of the approach. Ever see those on a U2?
I suspect a U2 is going to want the max possible wind over deck in order to make the softest possible touchdown for its relatively fragile airframe. Its wingspan is going to require wider foul lines and minimal deck parked aircraft; none aft of the forward JBDs.
Gliders are floaters on landing, and I'm sure the U2 is no exception. The problem is getting the speed down while keeping the engine throttled up enough to allow for a bolter. A splash off the angle would ruin everybody's day.
Cheers,
Wes

 

[Zipper730]

I might suggest your qualifications for making eyeball estimates of approach speeds might be a little thin? It takes an LSO thousands of hours of training and flying to do that.

Sure, I could concede being wrong. That said, I have some video clips I figure you might like to watch

U-2G


F-111B


The latter is merely for comparison.

Regardless, I have a Standard Aircraft Characteristics chart for the F-111B dated July 1, 1967.

 

[tyrodtom]

You're not looking at that U2 from a stationary point, you're on a carrier going maybe 30 knots or more.
And also into the wind,. Of how many knots ?

So that U2 may only be moving across the deck at 50 knots or so.

 

[nuuumannn]

I haven't seen an ATR or a Dash in years.

There's 20 of them parked up at work at the moment! About a third of our combined fleet. The turboprop fleet works its a** off in this country and the airline gets its money's worth. The ATRs aren't much liked by pilots, hosties or engineers, although at our level A-Check work on them is easy. I did a couple of heavy checks on them years ago and they are a pig. Despite their low operating costs - 68 versus 50 pax with the same engine and roughly the same fuel load as a Dash, they are maintenance hawgs and spend more time on the ground than the Dashes. A C-Check in a Dash can take around 2 weeks. In an ATR, normally 6 to 8 weeks. Its been calculated that for every man-hour of work on a Dash, there are two for an ATR. The Dashes are hardier, more versatile, can land on smaller strips and are cheaper to maintain, yet we have a ton of ATRs. Damn beancounters.

 

[Zipper730]

You're not looking at that U2 from a stationary point, you're on a carrier going maybe 30 knots or more.

I was under the impression you'd generally operate around 25 knots for most purposes. This might not be "most" purposes however...

And also into the wind,. Of how many knots ?

I have no idea as to that one. I'm not sure if there's even a generalized estimate for such matters...

 

[XBe02Drvr]

The Dashes are hardier, more versatile, can land on smaller strips and are cheaper to maintain

Hey, they're descendants of the Caribou, Buffalo, Twotter, and Dash 7, what do you expect ? Runs in the family. Hereditary bushwhackers. When our airline decided to replace their Fokker27s, they got sales teams to demonstrate SF340s, Dash 8s, HS748s, ATR42s, and even refurbished YS11s. Our pilots got to fly them, and our mechs got to do dailies on them. DHC was savvy. They brought along the Director of Maintenance, a shift supervisor, and the head flight attendant from one of our sister Piedmont Commuters who'd been operating it for awhile, in one of their planes in Piedmont colors. It made a great hit with all our people, and DHC was very generous with their time and fuel. Even I, as a lowly mechanic, got a little right seat time after I showed the demo pilot my ATP. Our recommendation to management, Flight, Cabin, and Maintenance, was unanimous - get the Dash! The CEO decided otherwise, saying: "The SAAB is cheaper, and besides, it LOOKS like an airliner, not an overgrown Piper Cub!". The SAABs were still having teething problems, and were a factor in our eventual bankruptcy.
My ex, an American Eagle new hire FO, had an ATR72 blow its right engine at liftoff on her third day flying the line, her leg to fly. All the turbine wheels came unglued and spit the bits out the tailpipe. Fortunately, the containment held, but the aft fuselage looked like it had smallpox. The prop froze with its blades locked in beta, flat to the relative wind. Fortuitousiy, they were making a full length takeoff on the longest runway at O'Hare, so even though ostensibly past V1, they were able to get it down and stopped safely. She said there was so much drag on the right side that full reverse on the left engine could just about keep it straight on the runway. They got it off the active and stopped on a high speed taxiway, but couldn't make the hard left turn onto the parallel taxiway from a standstill into the working engine. Besides, they were surrounded with emergency equipment, and the Captain had to shut down the left engine in a hurry, as one of the CFR trucks was about to stuff its foam nozzle in the intake. Kathleen got to sit in the cockpit and unwind a bit while the Captain offloaded the passengers and apologized for the ruckus. The passengers all wanted to know what "the girl" did wrong to cause this terrifying incident.
Cheers,
Wes

 

[XBe02Drvr]

I was under the impression you'd generally operate around 25 knots for most purposes. This might not be "most" purposes, however...

I have no idea as to that one. I'm not sure if there's even a generalized estimate for such matters...

Well here's a generalized estimate for you. It used to be considered that 35-40 knots wind over the deck was minimum for flight ops, in whatever combination of wind speed and ship speed it took to get there. Today's carriers top out in the low 30s hull speed, (officially anyway) so flight ops in a dead calm might be a shaky proposition. Dead calms aren't all that common at sea, so not usually a problem.
In the case of a U2, (did you notice how prone to bouncing it was?) you'd want the most possible wind over the deck to minimize impact velocity.
Cheers,
Wes

 

[Zipper730]

I never knew they'd operate with that much WOD. That said, you could see 90 knots during some of those approaches.

 

[XBe02Drvr]

I never knew they'd operate with that much WOD. That said, you could see 90 knots during some of those approaches.

Huh? How did you get from 35-40 to 90 knots? Or are you talking aircraft approach speed relative to the deck? A typical fighter approach AIRspeed at lighter weights of 130 knots into 35-40 knots WOD would give you 90-95 knots deck impact speed. Correct.

 

[Zipper730]

Huh? How did you get from 35-40 to 90 knots? Or are you talking aircraft approach speed relative to the deck? A typical fighter approach AIRspeed at lighter weights of 130 knots into 35-40 knots WOD would give you 90-95 knots deck impact speed. Correct.

The U-2 approach.

You said the normal WOD was around 35-40 knots over the deck, Tyrodtom said the U-2 could be crossing the deck at around 50 knots. So I figured that would be 85-90 knots for the U-2 approach.

 

[tyrodtom]

The U-2 approach.

You said the normal WOD was around 35-40 knots over the deck, Tyrodtom said the U-2 could be crossing the deck at around 50 knots. So I figured that would be 85-90 knots for the U-2 approach.

With a stalling speed of 94 knots, I don't think so.

 

[XBe02Drvr]

You said the normal WOD was around 35-40 knots over the deck

You did it again! If you're going to quote someone, at least quote them accurately. I said 35-40 knots WOD was a practical MINIMUM, not a "normal" operation. The example I gave of a 130 knot fighter is a bare minimum for a plane at its lightest possible landing weight, which is the only scenario that would work with only 35-40 knots WOD. Heavier or faster will require more.
In all those videos of flight deck recovery operations, didn't you notice how everybody's got all their gear strapped down tight, and any shirtsleeves that aren't are flapping in the breeze? It's a windy place up there.
Cheers,
Wes

 

[Zipper730]

With a stalling speed of 94 knots, I don't think so.

I was simply curious if the 94 knot figures was correct. So I was basing it on the footage. Which is why I wanted to know the WOD.

Looking at the velocity over the deck and minimums, it seems it's probably correct.

 

[tyrodtom]

You really think you can judge the velocity of a aircraft just by looking at a video ?

 

[XBe02Drvr]

You really think you can judge the velocity of a aircraft just by looking at a video ?

Of course he can! He's got X-ray vision, powered by Kryptonite.

 

[Zipper730]

*waves his white flag*