Power-On vs Power-Off Stall Speed

[XBe02Drvr]

Is that why many USAF planes were far more ornery than the USN counterparts?

In a world where your runway is 800 feet long and won't sit still, an ornery airplane is a non-starter.

Many people hate traits they possess.

"There's no saint like a converted sinner." One always hates the booby trap that almost got him and scared the crap out of him. I didn't hate the student so much as the attitudes and behaviors and the anxiety they caused me. As chief instructor, I wound up having to take over the arrogant, cocky students who gave the younger instructors a hard time. And if they really were incorrigible, I was the one who had to send them packing and then explain to management. I hated that part of the job.

What caused such a horrendously high fatality rate?

The AT6 was a handful for a competent advanced flying student, but disastrous for primary. Ask Drgondog or any other Texan qualified pilots here. Just too much airplane for a beginner. After the war, most of the WWII primary and basic trainers were considered unsuitable for initiating new aviators into the jet age, and most of them were pretty well worn out, to boot. The next generation trainers (T34, T28, etc) were not yet available, so they went with what they had in abundance, the T6.

Was it more docile in spins & stalls, or worse? I'm curious why there was such a high fatality rate with the USAF... I'm wondering if it was the aircraft, or the training.

The Stearman was a little challenging on the ground, with its tall narrow gear and poor forward visibility, but a solid, honest plane in the air, albeit a tad underpowered. Easy to ground loop, but hard to damage that way. AND A BLAST TO FLY! And the Navy continued to use them after the war until the new trainers came along. They saved their SNJs for basic and advanced.
Cheers,
Wes

 

[MIflyer]

There are some clubs in central Florida that rent out T-6's. We have had two come over to visit and then crash at our airport while trying to take off. In both cases it was a cool windy day with a strong about 50 degree crosswind.

 

[XBe02Drvr]

There are some clubs in central Florida that rent out T-6's. We have had two come over to visit and then crash at our airport while trying to take off. In both cases it was a cool windy day with a strong about 50 degree crosswind.

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Excellent testimony! Lucky this time. The good Lord protects fools and aviators, even when they inhabit the same carcass. The torque of those 600 ponies can catch the unwary pilot flat-footed, in the air and on the ground. Not your beginner's airplane. I'm told that once it starts to go, there's no getting it back and you're along for the ride.
Cheers,
Wes

 

[pbehn]

The AT6 was a handful for a competent advanced flying student, but disastrous for primary. Ask Drgondog or any other Texan qualified pilots here. Just too much airplane for a beginner. After the war, most of the WWII primary and basic trainers were considered unsuitable for initiating new aviators into the jet age, and most of them were pretty well worn out, to boot. The next generation trainers (T34, T28, etc) were not yet available, so they went with what they had in abundance, the T6.

Was that a change in attitude? When the Texan was designed was a level of losses was just expected and accepted and this attitude changed later?

 

[Shortround6]

I could very well be wrong but when the AT-6 was introduced it was perhaps the 3rd to 5/6th aircraft the student pilot flew. Most american pilots may have had around 100-150 hours before they flew an AT-6. Changing that to the AT-6 being either the first or 2nd plane they flew and with either no hours or a lot fewer was a recipe for disaster.
The AT-6 was supposed to be a stepping stone to operational airplanes. If it was too easy to fly the crash rate when converting from an easy to fly Advanced Trainer to operational fighters/dive bombers would have been much worse. At least that was the theory. Some "trainers" were purposely designed to be hard to fly. The AT-9 "Jeep" was so difficult that out of the almost 800 built none were released for sale to civilians as surplus at the end of the war.

 

[XBe02Drvr]

when the AT-6 was introduced it was perhaps the 3rd to 5/6th aircraft the student pilot flew. Most american pilots may have had around 100-150 hours before they flew an AT-6.

A typical WWII pilot trainee would start out with 10-20 hours in a J3 or similar plane as part of the precommissioning selection process, then 50-60 hours in a docile 160-220 HP Primary Trainer, such as a PT17, 19, 22, 23, or 26. Then on to Basic in a 450 HP BT13 or equivalent for another 50-60 hours, after which single engine candidates got polished up for 60+ hours in the AT6, while their multi engine brethren struggled with the AT9 and its peers. Then on to an OTU where they would get introduced to their combat mount, or some facsimile thereof.
When my instructor started flight training in early 1948, all the PTs and BTs were gone and students strapped on an AT6 for their first lesson. When he got to Advanced phase, the T33 was just coming into use, and he went from that directly into F86s and shortly, off to Korea. The real carnage in training was Primary in the T6.
Cheers,
Wes

 

[MIflyer]

Was only a few years ago that I learned that the B-25 began to replace the AT-9, Twin Beach, AT-21, etc. even during WWII. It actually was easier to fly than those trainers and was good for something else other than just training as well, such as a bomber, hack, or transport. One trainee pilot described how he was flying a B-25 while the instructors played cards a few feet away. One of the instructors reached over, shut down an engine and went back to playing cards; he would never have been that casual with a AT-9 or even a Twin Beech. The B-25 served the USAAF as a trainer and transport all the way to the late 50's. I recall a former RAF pilot who flew Hurricanes and Spitfires for the BoB movie say he was just how astonished he was at how easy it was to fly the Tallmanz B-25 they had there. He said that a typical Piper Tri-pacer pilot probably could handle it with minimum instruction.

But the AT-6 is a different story. A friend of mine went in partners with a couple of airline pilots years ago and bought a T-6G from the Haitian Air Force; they had got scared of it and switched to Cessna O-2's. He had a fun time going down there and fixing it up so he could ferry it back, only to be greeted at Opa Locka by the Teenage Mutant Ninja Turtles from some Federal agency, armed with both automatic weapons and bad attitudes, shouting commands such as "Put up your hands! Don't Move! Who are you? Shut up!" When he was allowed to produce his passport and they saw it was a red Government Agency one (he was a former NASA employee) they put 2+2 together, got 22 as an answer, apparently concluded that they had just jumped a CIA operation and beat feet out of there without so much as a "Excuse us, Mr. Spy, can we give you a lift to the airport terminal?".

He had been flying taildraggers since he was a teen, but one day in the T-6 he stalled and spun it and things got so confusing for a while that he seriously considered stepping outside and letting Sir Issac have the airplane.

 

[gumbyk]

But the AT-6 is a different story. A friend of mine went in partners with a couple of airline pilots years ago and bought a T-6G from the Haitian Air Force; they had got scared of it and switched to Cessna O-2's. He had a fun time going down there and fixing it up so he could ferry it back, only to be greeted at Opa Locka by the Teenage Mutant Ninja Turtles from some Federal agency, armed with both automatic weapons and bad attitudes, shouting commands such as "Put up your hands! Don't Move! Who are you? Shut up!" When he was allowed to produce his passport and they saw it was a red Government Agency one (he was a former NASA employee) they put 2+2 together, got 22 as an answer, apparently concluded that they had just jumped a CIA operation and beat feet out of there without so much as a "Excuse us, Mr. Spy, can we give you a lift to the airport terminal?".

Turning up in a foreign military military aircraft unannounced will do that. Even shipping a Spitfire out of the States can end up with plenty of questions to answer.

 

[XBe02Drvr]

Turning up in a foreign military military aircraft unannounced will do that. Even shipping a Spitfire out of the States can end up with plenty of questions to answer.

The old ADC alert pods next to our airline hangar were occupied by an outfit that made a business of importing foreign military aircraft, mostly ex iron curtain, and converting them to rich boys toys. They even had brief contracts to do aggressor stuff at Topgun and Nellis in their MiGs, until DOD sniffed out what a sleazeball operation they were.
Well, one day their honcho showed up in a nondescript black J35 Drakken, and all hell broke loose. It turns out that after he imported it into the US, a Fed got suspicious and checked with SAAB, only to learn that they had never manufactured a Drakken with that serial number. The plane had a counterfeit data plate and had been assembled from parts. It's career in the US was rather short, consisting of one TV ad (for Pepsi, IIRC) shot out at Mojave before the Feds impounded it and left it sitting in chains out by the FBO at BTV until the international incident subsided. The Swedes were NOT pleased!! The Feds tried hard to put the warbird outfit out of business, but the owner had many wealthy and influential folks among his customers with powerful legal resources, and they never managed to get him until he killed a couple kids in a boating accident. Reads like a thriller novel doesn't it? Life can be stranger than fiction sometimes.
Cheers,
Wes

 

[XBe02Drvr]

the Teenage Mutant Ninja Turtles from some Federal agency, armed with both automatic weapons and bad attitudes,

I and my passenger got similar treatment when we innocently taxied the flying club's T34 at 0600 past the facility at St Augustine that was converting T28 trainers into AT28 attack planes for the RVNAF. The snout of a Thompson has a BIG hole in it!
Cheers,
Wes

 

[XBe02Drvr]

former NASA employee

That's just NSA misspelled, isn't it?

 

[MIflyer]

No, he had been with NASA. Among his experiences there was spinning off the road going to the Cape while coming back from dinner, in a Corvette driven by some guy named Gordon Cooper.

He was A-Okay with the FAA. He had worked it out to make his required fueling stops and then get through the ADIZ, with the required radio contact. But when he landed at Opa Locka the T-6's rotten old tailwheel tire disintegrated. He was half expecting it to occur and told the tower that he had a problem and was going to have to pull off the taxiway onto the grass, which is a very good idea if all you have left for a tailwheel is a rubberless roller. The Ninja Turtles saw him pull off and presumably assumed he was parking in an area where he could make some kind of cargo transfer unobserved. And no doubt they get bored and are aching for something real to do.

Then... "Aha! No one expects the Spanish Inquisition!"

 

[drgondog]

Aerodynamics isn't my "bag" lol I would have to find the article. As I understand it, the aircraft is supported by a smaller and smaller section of the wings. Eventually a point is reached where it doesn't and one wing stalls with no warning sending the plane tumbling out of the turn. here it is but took ages to load http://www.wwiiaircraftperformance.org/mustang/Lednicer_Fighter_Aerodynamics.pdf

I loaded that a long time ago during some discussions with Soren.

Turn aerodynamics is a complex discussion but consider thatALL WWII single engine fighters without contrarotating props have upwash on one wing and downwash on the other - causing the lift distribution to be different, particularly at near stall AoA. Secondly, wing elasticity comes into play in high G/High AoA flight, pointing to examination of aileron authority vs control reversal.

Power required varies directly with Weight times CD/CL to the CL 'break/stall' region. Draggy airplanes, all else being equal (and they never are), require more HP in a to maintain a comparable rate of turn.

Factors that are introduced for Drag are a.) increase in both pressure and parasite draq due to increase in CL, b.) increased Induced drag due to increase in CL and c.) Trim drag of deflected control surfaces to maintain turn dynamics. Mach number is a factor but only a brief one as energy is lost so very rapidly in a turn.

Prop efficiency is also a factor, particularly in the relatively low ranges of velocity.

 

[XBe02Drvr]

Then... "Aha! No one expects the Spanish Inquisition!"

Funny you should mention. Those tough looking hombres that rousted us in St Augustine looked and sounded the part, right down to their barely comprehensible English. Rent-a-cops of the rougher sort, complete with Tompsons and ACPs.
Cheers,
Wes

 

[Zipper730]

The old ADC alert pods next to our airline hangar were occupied by an outfit that made a business of importing foreign military aircraft, mostly ex iron curtain, and converting them to rich boys toys. . . . Well, one day their honcho showed up in a nondescript black J35 Drakken, and all hell broke loose. It turns out that after he imported it into the US, a Fed got suspicious and checked with SAAB, only to learn that they had never manufactured a Drakken with that serial number. The plane had a counterfeit data plate and had been assembled from parts. It's career in the US was rather short, consisting of one TV ad (for Pepsi, IIRC) shot out at Mojave

I didn't know the Draken ever was in a Pepsi commercial...

The Feds tried hard to put the warbird outfit out of business, but the owner had many wealthy and influential folks among his customers with powerful legal resources, and they never managed to get him until he killed a couple kids in a boating accident. Reads like a thriller novel doesn't it? Life can be stranger than fiction sometimes.

Sadly, it doesn't really strike me as that abnormal. You have lots of people with connections, and the law means nothing. At least he finally was brought to justice, it's sad several kids had to die for it though.

 

[drgondog]

You have never hated life until you have to rig the flight controls on a V-Tailed Doctor Killa Bonanza.

I had a V-35 a long, long time ago - then a V-36. I actually enjoyed the FTDK more and the only annoyance was the Dutch Roll. I'm not sure that even the most skilled rigger could eliminate it completely.

 

[DerAdlerIstGelandet]

I had a V-35 a long, long time ago - then a V-36. I actually enjoyed the FTDK more and the only annoyance was the Dutch Roll. I'm not sure that even the most skilled rigger could eliminate it completely.

In the hands of an experienced pilot I am sure it is a great plane to fly. I love the Bonanza family, but I think I woukd stick to the standard config. Of course any Bonanza is out of my price range at the moment...

 

[drgondog]

The conversation re: AT-6 leads to some old memories. First, I would never have considered myself to be an AT-6 experienced person. My dad put me in it as a transition from J-3 to Cessna 150 to AT-6 before teaching me a few things about the P-51. The P-51 may be more straightforward than the AT-6, particularly in a cross wind landing. The AT-6 was a huge jump from a Cessna 150. The P-51 from AT-6, not so much.

A little history - the BT-9 was NAA first entry as a contractor for AAC, beating out established Severskey - and by all accounts, it and it's derivatives including the more powerful BC-1 for combat training, were easy to fly but also had some nasty stall characteristics initially. NAA embarked on a series of programs to enter the export fighter biz, as well as light bomber - all springing from BC-1. including NA-44 and NA-50 but the Harvard I was an upgrade from BC-1 and first bought by Brits (and Swedes and Aussie and Japanese, etc) for a variety of purposes but Basic Trainer was the strike zone. Increased HP and some mods were all introduced

The wings were pretty advanced for trainers and they were essentially the early choice for the Model P-509, pre NA-73X, before the NACA 125 laminar flow wing success at NACA in 1939 led to the gamble for the NAA/NACA 45-100 derivative for the Mustang. The NACA 23016 was the 'fail safe' wing for the Mustang.
but the Harvard I and then AT-6/SNJ jumped in primarily into Advanced Training programs.

(As a side note, my dad ran two pilot Basic training units in Training Command and most of his instructor time was BT-13. Interestingly when he escaped Training Command the next airframe was the B-26C, then he escaped bombers into fighters with the P-40. He had AT-6 time in the States before departing for England but over the last year in ATC it was split between BT-13, BT-14 and AT-6. During the war, his second day job 'hats' were pilot qualification and Accident Board at the 355th. The AT-6 was then important to check bomber pilots coming into the Scouting Force at Steeple Morden for suitability a Mustang drivers, and new pilots from US in instrument flying check rides. The 355th had the lowest accident rate in 8th FC.)

 

[fliger747]

I have a friend who had access to fly both the P-51 and AT-6 and said the Mustang should have been the trainer for the AT-6.

 

[MIflyer]

The Ryan ST was a delightful little sportplane and yielded the YPT-16 trainer. But the actual production trainer derived from it, the PT-22, had not only a larger cockpit opening but also had swept back wings, and that yielded more adverse stall characteristics. Added to that was the Kinner radial engine that produced more drag and the elimination of the beautiful fairings over the MLG, with still more drag. It did not fly as nicely as the sportplane.