June 24, 2005

Messerschmitts, Bears, and Tornados

In doing the work on the Me 262 post, the following occurred to me:

Given that the 262's engines were so finicky, I daresay that a P-51D or similar aircraft would be better at handling a rapid throttling up. To corrupt a quote from Episode IV, "Nobody worries about destroying a piston engine by rapid throttling up." "That's because piston engines don't overheat, weaken the turbine blades through that heat, throw a blade and promptly garbage the engine when they're throttled up. Jumo 004Bs are known to do that."

I snickered at the irony of a jet fighter being at the mercy of a piston-engined fighter in terms of performance in that particular circumstance. I then remembered another snicker story from the Cold War, one that was embarrassing to the RAF. It had to do with the Panavia Tornado F.3 ADV, the premier RAF interceptor during the 1980s.

One of the ADV's jobs was to intercept and escort various Soviet long-range reconnaisance platforms that would fly down from (ostensibly) the Kola Peninsula for a variety of missions. One of the more frequent types of aircraft that the RAF would see was the Tu-95 'Bear', in varying configurations. The Bear is a bomber with swept wings and turboprop engines, much like one of the design concepts for the B-52 Stratofortress.

As I remembered it, there was some situation where a Tu-95 was capable of escaping a Tornado ADV, and it involved acceleration. A quick bit of Google research confirmed my memories, and here's what was said:

It was stated in this newsgroup sometime back that a favourite way (for a large turbo prop) to get rid of a tailing interceptor is slow down a hundred knots or so, (by changing the prop angle @full engine RPM), forcing the 'ceptor to spool down a bit and/or pop some flaps, then change the prop angle back so as to accelerate away from the jet. Which has to use buckets of fuel spooling its motor back up (or afterburning). Repeat a few times & the jet gets bingo fuel.

and

It has been reported that the ADV needs a partial light on one afterburner to keep up with a Tu-95 Bear, for Chrissake! Apparently, a favourite trick of Bear pilots was/is to fly relatively slowly at fine pitch, let the ADV hold station, the coarsen the pitch and wait 2 minutes for the ADV to catch up.

That's probably a useless tactic in war because the ADV would have already fired on the Bear using medium range AAMs like the Sparrow or Sky Flash. Nevertheless, you've got to laugh at what is a very amusing parlor trick. Heh heh heh.

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June 20, 2005

TBG Aircraft Cheesecake - The Messerschmitt 262

JohnL over at TexasBestGrok has his latest installment of Aircraft Cheesecake. This week's installment concerns the strangely attractive Messerschmitt 262.

The Me 262 was the world's first combat-deployed jet fighter, developed during World War II as a strike fighter at the orders of Adolf Hitler. Luckily for the Eighth Air Force's daylight formations of bombers, the Me 262 wasn't developed immediately for interception operations, and thus took longer to get into service for that purpose.

Indeed, it was lucky for us that the entire German air war was on its knees by the time of the Me 262's introduction. Between a chronic lack of spare parts, fuel, trained pilots, and support infrastructure, the Me 262 could not be used to its full capability. The thing needed cover on its takeoff and landing cycles because it wasn't that maneuverable and took a while to perform either cycle. USAAF/RAF fighters got good at bouncing the 262 on its landing cycles, where it was largely defenseless.

I doubt that the course of the war in Europe would have been changed had the 262 been available earlier as an interceptor, but it certainly could have made our final victory much more expensive. A contrary view exists; apparently, the Eighth Air Force (and other heavy bombardment units) in the ETO were on the verge of cancelling operations at various points due to losses inflicted by the Luftwaffe's anti-aircraft artillery and fighters; with the 262 running around, the threshold for cancellation of the daylight effort might've been met, with unknown results for the war in Europe.


UPDATE, 23 JUNE 2005: The Superintendent of The Cold Spring Shops has a pleasant mention of this article, as does John over in the original TBG entry.

I'd like to revise and extend my remarks on the 262's shortcomings.

The primary problem with the Me 262 weapons system was its powerplant. This is not uncommon; the General Dynamics/Grumman F-111B died in part due to problems with the powerplant, and the Grumman F-14A Tomcat's TF30 powerplant was a piece of junk.

The 262 used the Junkers Jumo 004B turbojet engine as its powerplant; this was both good and bad. Good in that it was the first mass-produced jet engine, and bad for the same reasons. It personified Dr. Eldon Tyrell's (of Blade Runner fame) notion that "[t]he light that burns twice as bright burns half as long".

The 004B was a persnickety engine; software engineers might've called it a beta. For starters, it only had an operational life of 10-25 hours before the thing was ready for scrap or serious maintenance. I'm not sure what modern jet engines get, but you might burn up a pair of these things a week. That's not good.

Another problem with the 004B stemmed from the state of German metallurgy at the time; they couldn't mass-produce the kinds of metals necessary to make it a tough engine, and so they had to substitute lesser-quality materials for the manufacture of the turbine blades.

So it's got engines made by the lowest bidder. So what? So, you have to handle them accordingly.

Mishandling of the 004B---defined by rapid increases of the throttle---meant that the cheap turbine blades could break and be ingested by the rest of the engine. If you've seen The Phantom Menace, you know what happens when a pit droid (or a wrench tossed by Sebulba) goes into a pod racer's engine. This holds true on Earth as well; your engine becomes an expensive paperweight and you've got a potential fire on your hands. Additionally, the 004B did not spool up---provide additional power---easily. There was a fair amount of lag time between the pilot's advance of the throttle and the engine's response.

Keep these two facts in mind: It doesn't like to accelerate quickly and it takes its sweet time when you try.

What's this got to do with the takeoff and landing cycles, you say? Everything. Takeoff and landing will both require additional time, something the combat pilot doesn't always have.

The 262 required a decent takeoff roll and you had to be nice to the thing during the entire period, climbing away from the runway in a smooth manner while throttling back if possible, to keep the engines happy. Not necessarily fatal under ideal circumstances, but with the USAAF & RAF running around, you might not get to do this.

Worse yet was the landing sequence: The 262 pilot would get into position for landing, and essentially be stuck low, slow, and unable to accelerate off his approach if Mustangs or Thunderbolts showed up. You see the essential dilemma for the 262 pilot: He can't really run away from the battle in a hurry , and has to focus on getting to ground. That's not a very healthy strategy for survival, and it apparently accounted for a fair piece of the Me 262 losses.

Posted by: Country Pundit at 11:38 PM | No Comments | Add Comment
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June 13, 2005

Navy v. Pirates, 06 June 2005

No, I don't mean the US Naval Academy Middies versus the Pirates of Seton Hall or East Carolina, either. Nor was Jack Sparrow involved. Paging Miss Swann. No, I mean the real things.

That's right, the United States Navy engaged pirates on the high seas in 2005. The Arleigh Burke-class destroyer USS Gonzalez (DDG 66) was on patrol in the Indian Ocean when it received a distress call from a commercial freighter.

That's pretty nifty, even though our people did not actually kill any pirates. Alas, I was hoping they'd make someone walk the plank. At any rate, I suggest reading the referring article from No Such Blog for further details and a link to the Norfolk Virginian-Pilot's coverage of the event. If you go to the Gonzalez website, you'll find an MS-Word document file announcing the thing. What it says, I don't know; I'm a WordPerfect man.

Dip of the Jolly Roger flag to No Such Blog.

Posted by: Country Pundit at 12:53 AM | No Comments | Add Comment
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