Inverted flight 1940

@Propstrike;- Nice period film there in that Link. Correct, I would demure from discussion of specifics on an open forum.
When I started flying, spinning and recovery were a normal part of the syllabus – which hadn’t really changed since the Great War. Today, other, arguably less relevant material for GA (Such as CRM.) has been added, at the expense of vital spin training. In my opinion, simply teaching a student to avoid the incipient spin is next to useless, since, if he/she gets into one in a average GA a/c it’ll have hardly been deliberate…and at that point rather too late to get out the books…! It’ll also probably be at low altitude…. The effects of this backwards step have only been mitigated by the generally very docile characteristics of modern GA a/c.
In general terms, I’d say that if one is going to aerobat any a/c, then practicing spin-recovery – with plenty of air below you – is essential. Most aerobatic a/c are strong and don’t break easily, but they will still spin very well. I haven’t aerobatted a Stearman, but in the Pitts, it’s certainly alarming at first, as being so small & close-coupled, it all happens pretty fast. The height loss is pretty sobering too, especially if one makes a hash of it…. The ground certainly always looks a lot closer when spinning inverted…..

Inverted spins ARE a bit different, and they still kill. Two White Waltham aircraft were lost this way in the last few years. The crux of the problem is that it is disorientating, and G is pushing you out of your seat, and it is scary stuff. The Stampe we lost spun inverted out of a bungled roll and could not be recovered in 2,000 feet, which sounds quite a lot, but is about 700 metres, roughly the same length of a typical runway at a small airfield. I would post a link to the accident report, but I know your feelings on that. :rolleyes:

Perhaps the most useful aid I found when trying to understand a bit more, dates from the 1940’s. It is well worth a watch.

http://www.youtube.com/watch?v=_J9N8nQV6Hk

An astounding fact, which also implies that fighter pilots, were also probably not trained on inverted spin recovery.
I don’t see how they could have been!

I can’t think of a two seater capable of inverted, until the two seat Spit, of which there were very few, so perhaps this was never done.

It means that in combat, in later machines, it must have been possible to get into a whole lot of inverted trouble.

You seem to be making a lot of presumptions…… Why do you presume that the engine needs to be running to get into an inverted spin..? It doesn’t, – which is why aerobatic gliders can spin inverted. I’m sure there were many RAF two-seater training a/c that were spun inverted, – intentionally or not…!
You are then presuming that the pilots in combat were unfamiliar with the flight dynamics of inverted flight. Plainly, they were not. Neither is it even necessary to be inverted to enter an inverted spin. In some machines a botched recovery from an erect spin can translate directly into an inverted spin. This is quite normal behaviour. Any pilot flying an aerobatic machine will have been trained/briefed on what to expect, thus, given an awareness that he/she is in an inverted spin, – and there is sufficient height, recovery is routine.

I’m not an expert on the Merlin, but in common with just about every military a/c of the time – and probably most civil a/c, it was dry-sumped. (It’d be catastrophic to have an installation with inverted fuel and not oil.). Normally with engines of that period with heavy airscrews, at aerobatic speeds, the airscrew would windmill, and, although the engine isn’t producing power, all of the ancillaries are still being (Mechanically.) driven, thus it is normally being lubricated. Were this not the case, the handbook would note this and the a/c would be appropriately placarded. They aren’t, so they were.

Interesting to watch the test pilots demo with inverted passes, Quill or Henshaw I think it was. A horendous dive and a whistling, gliding, engine throttled back inverted pass, sort of looks and sounds wrong.

Me109 pilot…”WEEEEEEEEEE”…….RAF pilot…”B@st@rd”

An astounding fact, which also implies that fighter pilots, were also probably not trained on inverted spin recovery.
I don’t see how they could have been!

I can’t think of a two seater capable of inverted, until the two seat Spit, of which there were very few, so perhaps this was never done.

It means that in combat, in later machines, it must have been possible to get into a whole lot of inverted trouble.

There were a/c around in the 20’s/30’s with inverted fuel/oil systems but probably not any normal RAF service aircraft !

Basically, I guess it’s safe to say that before introduction of direct fuel injection (Daimler Benz 601 and Jumo 211, bench tested first in 1935), injection-type carburettors (Bendix-Stromberg, 1944) and speed/density-type carburettors (SU, Rolls Royce, Bristol, somewhere during the war), all of these devices working WITHOUT any float chambers, there were no planes out there, capable of sustained inverted flight or negative G manoeuvres. Well, not until famous “Mrs Shilling’s orifice” was introduced as a stop-gap measure.

Therefore, although I’m not familiar with engine details of pre-war biplanes mentioned in initial post, I’d presume they were most likely positive-G-only machines indeed.

It’s not really about inverted flight, but as you said, negative G manoeuvres. None of these aircraft can sustain inverted flight because the oil system will not sustain pressure, nor will the oil scavenge system work.
The Hurricane II with the Merlin XX did have the required modifications to work under negative G, yes. It would still put out some black smoke, but would keep running.

Some engines were field modified in 1940, but I don’t know the dates. The Merlin II and III engines in use at the time were not fitted with negative G carburettors at all, only modified, in a few cases.

Pete