[ARC5] "Was the P-51 Mustang unbeatable?" on Quora
MARK DORNEY
mkdorney at aol.com
Wed Aug 18 13:55:25 EDT 2021
And it is still impossible to smoke wearing an oxygen mask.
Mark D.
“In matters of style, float with the current. In matters of Principle, stand like a rock. “. - Thomas Jefferson
Sent from my iPhone
> On Aug 18, 2021, at 1:49 PM, MICHAEL BITTNER <mmab at cox.net> wrote:
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> FWIW, here are my thoughts on this hopelessly off-topic, but nevertheless interesting discussion.
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> In Navy basic training in the SNJ, the only maneuvers we were taught that involved negative G were the slow roll and the Immelmann turn (first half of a loop followed by the last half of a roll). In both maneuvers the float carburetor would cause the engine to quit during the brief period of inverted flight while holding the nose up slightly above the horizon with forward stick during the roll. No big thing and just part of the maneuver. Engine always restarted when positive G was restored.
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> The Stuka pilots may have pushed over into a dive, but we always started from level flight at an angle to the trajectory of the dive and then "peeled off" with a diving turn into the dive trajectory. There are numerous WWII movies showing SBD dive bombers performing this maneuver. No neg G involved.
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> In mock dog fights (I've never been in a real one) in SNJ, T-28B and T-34B aircraft, I never saw any use for a negative G maneuver and it seemed to me that doing so would just set myself up as a sitting duck. The Germans trimmed their fighters for inverted neg G when bailing out. There are numerous WWII Allied gun camera shots showing dog fights ending this way.
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> The T-34B had no problems with neg G flight as it had fuel injection and a pivoting "flop tube" in the oil tank that would follow the oil wherever the G forces might take it. The real issue with the T-34B was zero G during which the oil and the flop tube would occasionally part company and a slug of air would enter the oil system. This happened to me when my student erroneously entered a brief zero G condition at the top of a loop. I saw the oil temp gauge go to max and the oil pressure gauge go to zero. I cut the engine and set up a glide to a nearby practice landing field. After landing, we found oil dripping out of one of the exhaust stacks along with little shards of aluminum and piston ring. Apparently a valve had stuck open and a piston had pounded itself to pieces on the stuck valve. Mike, W6MAB
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>>> On August 18, 2021 at 10:26 AM Francesco Ledda <frledda at att.net> wrote:
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>>> Both loops, Immelmanns and split Ss are used in combat and are positive G maneuvers. Zero G and negative maneuvers are usually very short and not liked by pilots.
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>>> Sent from my iPad
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>>> On Aug 18, 2021, at 09:18, Francesco Ledda <frledda at att.net> wrote:
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>>> doesn’t know
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>>> Sent from my iPad
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>>>> On Aug 18, 2021, at 08:53, Francesco Ledda <frledda at att.net> wrote:
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>>>> There is a huge difference between inverted and negative Gs. Often inverted flight still ha positive Gs, so the engine doesn’t it is in inverted flight!
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>>>> Sent from my iPad
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>>>>> On Aug 18, 2021, at 08:47, MARK DORNEY via ARC5 <arc5 at mailman.qth.net> wrote:
>>>>>
>>>>> Ok, so the P-51 Merlin engine couldn’t work inverted for long periods. But the Germans didn’t use the Merlin engine.
>>>>>
>>>>> Mark D.
>>>>> WW2RDO
>>>>>
>>>>> “In matters of style, float with the current. In matters of Principle, stand like a rock. “. - Thomas Jefferson
>>>>>
>>>>> Sent from my iPhone
>>>>>
>>>>>> On Aug 18, 2021, at 7:48 AM, Michael Hanz <aaf-radio-1 at aafradio.org> wrote:
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>>>>>> Autoweek had an interesting rundown on the Packard version of the Merlin, including the dry sump system: https://www.autoweek.com/car-life/classic-cars/a30763715/rolls-royce-vs-packard-who-built-a-better-merlin/
>>>>>>
>>>>>> Most of the aircraft engines had variations on this theme, it seems. The need to operate in negative G environments for short periods pretty much demanded a dry sump. They all sported a tiny crankcase size (just big enough to allow room for a baffle to slow the high velocity of oil being slung off the crankshaft rods and bearings), scavenge pump(s) in addition to the normal pressure pump required in an automotive engine, multiple collection points, large remote collection tank (many gallons rather than a few quarts). The diagram is from a 1938 Merlin variation:
>>>>>>
>>>>>> <hnocdihaldgdkdkh.png>
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>>>>>>> On 8/17/2021 10:51 PM, Richard Knoppow wrote:
>>>>>>> A google search for Rolls Royce Merlin will produce a huge amount of information about this engine. There were many versions and variations. Some early ones had cooling problems that were addressed in later versions, some had lubrication problems as I suggested in my earlier post. There are comparisons with the Alison engine. Also look up information on maneuvering fighter planes for more on inverted flight.
>>>>>>> I am not a pilot but I'll bet we have some former fighter pilots on the list.
>>>>>>>
>>>>>>>> On 8/17/2021 7:41 PM, Robert P. Meadows wrote:
>>>>>>>> Not so much the oil system, but the FUEL system and carburetor.
>>>>>>>> R
>>>>>>>>
>>>>>>>> -----Original Message-----
>>>>>>>> From: arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> On Behalf Of Richard Knoppow
>>>>>>>> Sent: Tuesday, August 17, 2021 5:48 PM
>>>>>>>> To: arc5 at mailman.qth.net
>>>>>>>> Subject: Re: [ARC5] "Was the P-51 Mustang unbeatable?" on Quora
>>>>>>>>
>>>>>>>> I only skimmed the article. One thing that is often overlooked is that the engine in the P-51 like its British counterpart could not fly inverted for more than a few seconds.
>>>>>>>> The method of lubrication used in the Rolls-Royce/Packard engine would not provide adequate lubrication when inverted. That was a limitation in dog fighting. The Spitfire had the same problem since it used essentially the same engine.
>>>>>>>> BTW, I saw a P-51 taking off from the Santa Monica airport a few years ago. The pilot just sat it on its tail and went up at an amazingly steep climb. Very noisy. They are such beautiful planes.
>>>>>>>>
>>>>>>>>> On 8/17/2021 12:10 PM, Hubert Miller wrote:
>>>>>>>>> Timewaster warning: this is possibly a waste of your precious time,
>>>>>>>>> but I found this Quora article quite interesting. Which leads to other tempting timewasters...
>>>>>>>>>
>>>>>>>>> https://www.quora.com/Was-the-P-51-Mustang-nearly-unbeatable-during-th
>>>>>>>>> e-Second-World-War
>>>>>>>>>
>>>>>>>>> -Hue Miller
>>>>>>>>> ______________________________________________________________
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>>>>>>>>> This list hosted by: http://www.qsl.net Please help support this email
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>>>>>>>> --
>>>>>>>> Richard Knoppow
>>>>>>>> 1oldlens1 at ix.netcom.com
>>>>>>>> WB6KBL
>>>>>>>>
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>>>>>>
>>>>>> --
>>>>>> Michael Hanz - KC4TOS
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