settle a dispute?

[mat777]

I wonder if you knowledgeable chaps could please settle a disagreement over a certain incident?

Having read various articles on the Gloster Javelin, my understanding is that above 45 degrees attack angle, the delta wing cuts off all airflow to the t-tail, the plane stalls, and then falls out the sky like a flat iron with no way to recover it due to zero airlflow over the control surface. Thus as Peter Lawrence found out with unfortunately the ultimate cost.
A friend of mine, who happens to be an ex- chipmunk pilot reckons that "Much like a flat spin experienced by anyone running out of lift with an over generous aoa then. Peter Lawrence simply ran out of oppurtunity to recover. Even a delta formation with no airflow over the surfaces has a limited amount of control. Given enough alitude a skilled crew will recover"

So, was the situation ever recoverable or was Lawrence as doomed as all the official accounts seem to suggest

[Kitbag]

You may get an authoritative answer from someone like Ghengis the Engineer over on the Flight Test thread. From my very limited understanding you are correct, that type of stalled condition is almost impossible to recover from.

[goudie]

If you've not read it, this article, on the subject, might answer your question

javelin | folland aircraft | 1956 | 1033 | Flight Archive (http://www.flightglobal.com/pdfarchive/view/1956/1956%20-%201033.html)

[mat777]

thanks guys, Im currently reading the pdf and have reposted the query to the test boards as well.

Out of interest, I gather said Javelin impacted terra firma in Ashton court estate, which is but 5 minutes up the road from where I currently reside... does anyone know the exact spot as I cycle around the grounds a lot and would be interested to see where it happened (sadly I suspect it probably lies under what is now the perfectly manicured golf course... :* )

what doesnt tally is that eyewitness accounts say it narrowly missed Bristol grammar school... which I can only assume has moved since 1953 as it is now located next to the University.. far too far south and the wrong side of the river

[henry crun]

Stalling was prohibited in the Javelin, and an inadvertant stall would almost always result in a spin.
It can be seen from the following quote from the Javelin pilots notes that recovery was not impossible.

"The direction of spin is usually unpredictable, even from turn to turn. The rotation is very slow, and the nose pitches up and down fairly regularly, through as much as 70 degrees. The rates of yaw and roll will very with the pitching.

The stick forces are very light throughout, and there is no kickback on the stick.
However, the rudder moves fiercely fully one way and the other, and the forces may be extremely heavy; it is recommended that the feet are merely kept lightly on it throughout the spin.
The airspeed varies from "off the clock" to about 90kts.

When the aircraft is clearly in a spin, take the following action
1. With the control column fully back apply full aileron in the same direction as the spin.
2. With full aileron applied, move the control column fully forward into the corner.
3. Keep the feet lightly on the rudder pedals.

It is unlikely that this action will have any effect for one or even two turns, certainly it seldom has any immediate result.
The control column should be held fully in the corner, the direction of the spin may reverse, and in this case the control column should be held right forward and moved sharply fully over into the new direction of spin. No force should be used to oppose any rudder movement.

Recovery generally follows one of two main patterns, type 1 being the more usual.
1. The rotation ceases, and the aircraft hangs in a nose down attitude for a second or two. However, the control column must be still held fully in its corner until the aircraft does a sharp nose down pitch or "bunt".
Minus 2 1/2 G is about the usual figure for this and is quite unmistakable.
One the aircraft has done this the spin has stopped.
The speed rises rapidly, and only then should the controls be centralised and the aircraft eases out of the dive.
Attempts to centralise the controls and recover in the stage when the rotation has ceased, but before the aircraft had bunted, will lead to a further spin with delayed recovery.
The rudder should be left alone, when recovery is complete it will centralise itself.

2. After taking recovery action, the aircraft enters a fast spiral in a steep diving attitude. The spiral may be in the same direction as the applied aileron, or against it, but this condition may usually be recognised because: a) the pitching ceases, and b) the speed rises, c) the rate of rotation is steady and fast.
Once the speed is over 200 knots, the controls may be centralised, and the aircraft eased out of the dive.
The rudder will centralise itself when recovery is complete, and it should to its own devices."

[Kitbag]

Never having driven an aeroplane how does the advice given quoted by Henry Crun differ, if at all, from aircraft without 'T' tails?

[chiglet]

Two [ex] Javelin pilots, and one nav swore that to get out of a spin, the Nav ejects. This apparently disturbs the airflw enough to regain control. They may have been winding me up, but as no beer was involved.... I dunno

[Shaggy Sheep Driver]

I have never flown a Javelin (or any jet, delta or not) but have part-owned a Chipmunk for well over 30 years. I can say the Chipmunk spin is nothing like the description of the Javelin spin. It is recovered in the usual manner - power off with ailerons central, full opposite rudder, pause, stick forward until the spin stops (might need a lot of forward stick!), then centralise and ease out of the dive. I have never experienced a Chippy flat spin (if it can be made to do it...).

I also flew the Yak 52 for a few years and did flat spin recovery in that as a flat spin can be inadvertantly entered of a botched aeros manouvre in the Yak. That spin is stable and flat with a high rate of rotation and descent. There is no pitch occillation, and it is recovered with power off, full oposite aileron with full down elevator (so stick hard into the front corner), and full in-spin rudder all simultaniously, controls centralised when spin stops. Agaian, this is nothing like the Javelin spin description.

The Javelin is an odd configuration, being a thick-winged delta with a tailplane. Deltas don't usually stall in the conventional sense, they just reach very high drag rates at high AoA wih associated high rates of descent. But, as was observed in the Concorde crash at Paris, they can eventually 'depart' in roll, though Concorde of course had a narrow and thin delta wing with no tailplane.

[Brian Abraham]

No Concorde crash Shaggy, try the Russian version. ;)

[DH106]

Huh Brian, "No Concorde crash" !? :eek::confused:

There was indeed a Concorde crash at Paris, and it did roll over just before impact, although the roll may have been more to do with large asymmetric thrust and fire/damage on one wing than a 'true' delta aerodynamic effect.

The Russian 'Concordeski' crash at the Paris airshow was a structural failure whilst attempting to recover from an upset, not a stall.

[Shaggy Sheep Driver]

DH is correct. I was referring to the Air France crash in 2000, not the much earlier TU144 in-flight break up at the Paris air show.

[teeteringhead]

Further to henry crun's extract from Javelin Pilots' Notes, ISTR an ex-Jav mate telling me it went on to say words to the effect of:

"If spin recovery has not started by 25 000 feet, crew should eject!"

[Brian Abraham]

Doh. :ugh: :ugh: :ugh: Sorry Shaggy. All I can say in defence is that one was too recent for me to consider it "history". More like still living it. Sorry. What lead me to the 144 was the "stall", as it's one reason put forward by some parties as being one of the sequences leading to the breakup. The attached video would seem to show an AoA of nearly 80° at the time of breakup. Of course nothing definitive has ever been published.

http://www.youtube.com/watch?v=dPQlbhgD4YQ

[DH106]

Brian - it's difficult to see in that clip where the actual breakup begins.

In this clip it's a bit clearer, starting at about 1:40.

TUPOLEV TU-144

The 144 is in a dive an pulling serious G's to recover when the left wing fails (some say the canard fails first). But the angle of attack is much more modest than 80 deg immediately prior to the breakup. It's a G loading issue rather than a stall.

[Shaggy Sheep Driver]

Brian, are you confusing AoA with pitch attitude?

[Legalapproach]

Javelin Pilot's Notes (FAW Mk 7) provide:

If the aircraft has not stopped spinning or is stalled at or below 15,000 feet above the ground it should be abandoned.


(f) Stall with flaps and undercarriage down

Tunnel and model tests show that the aircraft should not spin in this condition, but once stalled the only likely method of recovery is to raise the flaps and undercarriage. The aircraft will then probably spin, and recovery as above should be taken. The stalling speed with flaps down is about 90 to 95 knots.

[Brian Abraham]

My bad interpretation Shaggy. The video posted by DH106 reveals all.

[teeteringhead]

If the aircraft has not stopped spinning or is stalled at or below 15,000 feet above the ground it should be abandoned. ... thanks for the correction Legalapproach.

My 25 thou must be either my bad memory or a B**llsh***hg Jav mate. Probably equally likely!

[BOAC]

25 is probably where the nav departs to get to the pub to get the beers in:)