Aviation myths that will not die

[Shortround6]

Post was in responce to Post #281 through a chain of posts.

Relevant part of #281 was "The Corsair was the first US Fighter to reach 400 mph"



Yes a few race planes from the Early 30s set speed records of over 400mph. Basically the Supermarine S6b and the Macchi M.C. 72.

I know I used the word "aircraft" when I should have used the word "fighter". The seaplanes and the other aircraft you mention don't really qualify, the seaplane racers for obvious reasons.
Planning for the F4U and and P-38 started in 1938 (if not before). Requirement for the Typhoon was "officially" from 1938 although they had been thinking about it earlier.
MIg requirement is later but they turned it into hardware quicker.
He 100 is a real can of worms, earlier in timing than the others it is a confused mess when trying to figure out what was "mil-spec/RLM specifications" and what was not. There is dispute about actual speeds of "service versions" vs prototypes. (leaving the record breaking aircraft out of it). That is a problem the Mig-1/3 also had. Granted the F4U and P-38 didn't have any service versions in existence in 1940.

As a "fighter" the He 100 had little or no protection ( nothing did in 1939) and the armament was best described as pathetic.
Please note Wiki :

• Guns: 1 x 20 mm (0.787 in) MG FF cannon and 2 x 7.92 mm (0.312 in) MG 17 machine guns or 20 mm (0.787 in) MG 151 cannon.

Now the problem I have with this is that the Germans were not able to get a working MG FF cannon firing through the prop hub into the 109 until the F model which showed up in the fall/winter of 1940, 6-9 months after production of the He 100 ended. As far as the MG 151 goes........First used (in through the prop form) by the 109F-4 in June of 1941, well after a year after they stopped building He 100s.
Basically any He 100 in "service use" or exported (does that count as Mil-spec?) had a pair of 7.9mm mgs.

 

[wuzak]

Or is that a myth?
The others are specific descriptors, not generally generic, like 'mil-spec', or 'metric'.

United States Military Standard - Wikipedia, the free encyclopedia

"A United States defense standard, often called a military standard, "MIL-STD", "MIL-SPEC", or (informally) "MilSpecs", is used to help achieve standardization objectives by the U.S. Department of Defense."

 

[Shortround6]

Or is that a myth?
The others are specific descriptors, not generally generic, like 'mil-spec', or 'metric'.

Mil-Spec includes "everything". You want a Mil-Spec Ar-15 Rifle? ALL the parts have to be to the original specification alloy/s and heat treatment, not just look like the originals or even fit in an interchangeable manner.
First Colt AR-15s sold to civilians were built using some parts that failed US Military inspection. Let alone changes in the firing mechanism or changes in internal dimensions that prevented military trigger/group and hammer from being installed in a Civilian receiver.
Nowadays with dozens of clones on the market it doesn't matter if company XX is using a stronger alloy or better heat treat or what ever, if not built to the original specifications (alloy/s--heat treat ,etc) it is NOT a Mil-spec gun.

Mil-spec applied to aircraft can also get a bit 'squishy". P-40s for example. after a certain point in production (and after being used in combat for a while) P-40 weight charts delete oxygen equipment as "standard" It could be fitted but if the plane was to meet "book" gross weight something else had to be left out, like fuel or ammo.

Also fuel was somewhat iffy on the early P-40s. While the tanks could hold 160 US gallons the "normal Gross weight" only allowed for 120 gallons. This was all internal, no drop tank. What was Mil-spec in this regard?

It was, in part, Mil-Spec that caused the trouble with the American Hispano cannon. the allowable tolerances for "cannon" were greater than they were for small arms (machine guns). The 20mm by it's bore size, fell into the cannon category.

 

[GrauGeist]

Merlins in Meteors??

What??

 

[Shortround6]

The tank engines were purpose built. Many people claim they used old aircraft engine blocks at times. This may or may not be a myth, Removing the supercharger and aircraft reduction gear is not as easy at sounds. The back of the prop reduction gear case was cast in one piece with the crankcase. The rear end of the engine may have had significant changes between the supercharger drive/and accessories and the tank accessory drive parts. Internal parts are much more interchangeable.

 

[GrauGeist]

That's like assuming that since the M4 Sherman had a radial engine, it must be an aircraft engine.

Which is not the case.

The Caterpillar RD-1820/D200A (Diesel) and Continental R-975 (gasoline) were purpose-built for that application.

 

[MiTasol]

I may well be wrong but I was always under the impression that the Continental R-975 was a Wright R-975 modified to suit tank installations with different nose case and rear cases but basically the rest was the same

 

[GrauGeist]

I may well be wrong but I was always under the impression that the Continental R-975 was a Wright R-975 modified to suit tank installations with different nose case and rear cases but basically the rest was the same

key word: modified

Continental built the R-975 specifically for the M2, M3, M4, M7, M18 and Canada's version of the M3.

To convert a Continental R-975 to aircraft fitness would take some work and I don't think it would have been certified by the FAA as airworthy.

Continental did manufacture an aviation version post-war, the R9-A

 

[GrauGeist]

Modified, sure same as Merlin/Meteor, but many Merlin parts, including those rejected as not of 'aviation-spec' went into Meteors.
Funnily enough, the hard run Meteors showed the same valve gear wear issues as the Merlin, despite being de-rated.

The German & US SOHC V12s ran roller cam-followers,
& Ford had gone DOHC for his 'improved' Merlin V12, that as the GAA ended up in tanks.

Where are you coming up with all of this sh!t?

Are you actually sober when you're posting this?

 

[GrauGeist]

DO you want to put a buck on the barrel head, to see who's the one " coming up...with shit"?

Hell yes, you bring it...

I've been hammering your stupid crap all night with hard fact...how much further do you want to go?

 

[GrauGeist]

I don't do wiki

Go back over every single one of my posts and prove me wrong with legitimate sources, including authors and page numbers.

Go ahead, I'll wait.

 

[DerAdlerIstGelandet]

Take a few days off from the forum and hell breaks loose.

Remain civil!

And Shooter, I still have a lot to respond to you. Don't think I have forgotten.

 

[pbehn]

Take a few days off from the forum and hell breaks loose.

Remain civil!

And Shooter, I still have a lot to respond to you. Don't think I have forgotten.

He is busy raising $1000

 

[Shortround6]

See here: www.raeme.info/ops8410.php & here: www.fordgaaengine.com

Next you'll try & dispute the fact that the USN used British Napier mills in its high-speed patrol boats in 'Nam too.

Edit: Added DOHC Ford data.

A Napier Deltic diesel is a far cry from the Napier Sabre engine. They are both internal combustion engines and that is about as close as you are going to get. The Deltic diesel used the patrol boats was basically 3 Jumo 205/7 diesels ganged together.

Very interesting engine (also used in railroad locomotives) but has got sod all to do with Napier aircraft engines or this topic, wide ranged as it is.

 

[pbehn]

A Napier Deltic diesel is a far cry from the Napier Sabre engine. They are both internal combustion engines and that is about as close as you are going to get. The Deltic diesel used the patrol boats was basically 3 Jumo 205/7 diesels ganged together.

Very interesting engine (also used in railroad locomotives) but has got sod all to do with Napier aircraft engines or this topic, wide ranged as it is.

My father used to drive them he said they were the best diesel/electrics, not sure how well they would have fitted in an airframe. Obvious when you see the graphic, I was surprised when I learned they were two strokes.

 

[Shortround6]

Thank you Pbehn

I would note going back to sources that it is best to be careful when citing car fanboy sites to double check things. Many of these sites think High Performance started in 1946

From the site supplied by James W. " The Merlin's spark plugs were located on the exhaust side of the head just below the exhaust ports, whereas the GAA had its plugs centrally located in the combustion chamber, as per modern practice.

Italics by me.

Cross section of a 1912/13 Peugeot Formula One engine.
Hmmm, double overhead cams, 4 valves per cylinder, central spark plug.
Modern practice dated to before the first WW I.
There is also a lot of confusion between hemispherical combustion chambers and pent roof chambers. I have no idea where the dividing line is (in the angle between the valves) and no interest into getting into an argument over it. I would note that using a 4 valve head makes the use of true "hemi" head a bit difficult unless the valves are not only angled from the ones on the opposite side but from each other on the same side but that complicates the heck out of the valve gear

 

[pbehn]

There is little new under the sun, many of the "new" technology on motorcycles (monoshock and leading link suspension) was actually tried years ago.

 

[Shortround6]

Tell that to GM

all their old industrial diesels used 4 valve heads. Air is blown in through the side through piston ports. all four poppet valves in the head are exhaust valves. Combustion chamber is flat.

 

[pbehn]

Sod all? The Jumo 2-stroke (which the Napier was based on), powered the Ju 86P high-altitude recon-bomber.

"based on" in the sense that it was a similar arrangement

 

[pbehn]

Yep, so similar they had to buy a licence to build them- well until WW2 that is..

They license built an aero engine, then built a marine engine with opposed pistons.