BF-02 Supersonic

spazsinbad wrote:I have read that the drive shaft in STOVL flight is closely monitored by the automatic ejection system.

Not smart in my book as sensors are difficult to design and prone to failure!

Wow … I distinctively remember watching the video of a pilotless Harrier on BBC news sometimes in the 90’s. An American C-130 took the footage. I can’t find any video on the net!

A HUGE Bristol Channel rescue operation involving hundreds of coastguards,lifeboatmen and aircrew was underway today after a pilot ejected leaving his RAF jet to fly on for an hour before Crashing into the sea. Two RAF Nimrod maritime patrol aircraft, four rescue helicopter`s, three lifeboats Including the Mumbles boat and dozens of land-based Coastguard teams were involved In the search, which is continuing. The RAF Harrier jump jet had taken off from a Dunsfold airstrip, near Guillord, and the last voice contact with the British Aerospace civilian test pilot was when the aircraft was 15 miles north of Southampton. The Harrier crashed 240 mile`s out at sea and, given Its terminal speed of 400 knots, could have been flying pilotless for up to an hour. The drama began at 6 p.m. when a U.S. Military transport plane's crew spotted the GR5 Harrier south of Ireland noticed the canopy had gone the pilot was missing. The pilot, who had not named, had been undertaking. predelivery test fight in the British Aerospace-bull Harrier. A B.A. spokesman said they were extremely concerned for his safety.

Source: http://www.coastguard.ukf.net/jetair.html

VarkVet, smart or not that is the system. Also there is a pilot controlled sensitivity switch for smart ejection but what it does exactly I don't know yet. Vaguely I recall reading that a guess was that it could be more sensitive for less aware newbie pilots whilst experienced pilots could dial down sensitivity to allow possible corrective action before ejecting.

BTW there have been any number of 'not appropriate or appropriate in the circumstances' ejections over the years - rightly or wrongly - where the aircraft without aircrew. has continued on to crash at some future point. Has happened a few times within view of flight deck of many USN aircraft carriers for example.
____________

One example of the scuttlebutt about the 'auto eject' feature:

http://www.airwarriors.com/forum/showth ... 14&page=34

"A group of Harrier guys were picking the brains of a group of JSF engineers are few years ago when they were socializing the lift fan design. What happens when the clutch fails, we asked? They assured us that it was designed to be fail-proof. Since complexity tends to be the natural enemy of reliability we again asked - so, really, what happens when it fails? They again insisted it couldn't fail. We just gave them the stink eye for a minute and then one of them piped up with - "Well there is an auto-eject mode on the seat that is only triggered in the event of lift fan or clutch failure". Seems that if the lift fan were to fail or the clutch were to give out, the subsequent pitch rate would be impossible to beat with a manual ejection. So in that scenario, HAL takes care of business for you. At least that was the selling point, no idea if that design feature is still incorporated."

spazsinbad wrote:VarkVet, smart or not that is the system. Also there is a pilot controlled sensitivity switch for smart ejection but what it does exactly I don't know yet. Vaguely I recall reading that a guess was that it could be more sensitive for less aware newbie pilots whilst experienced pilots could dial down sensitivity.

One example of the scuttlebutt about the 'auto eject' feature:
At least that was the selling point, no idea if that design feature is still incorporated."

Great … this is getting better all the time (if you’re not bullshitting)
I was planning to go to bed early so I could get up early and watch Germany play England in the World Cup!
Now I’m going to have nightmares because I’m thinking if HAL has a “bug” up his a$$, he will be littering the countryside with coherent pilots and smoking holes! Regardless of the sensitivity switch!

VarkVet, why would I B/S?
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"Smart ejection seat from Martin-Baker on display

http://www.ejection-history.org.uk/proj ... s/2004.htm

An aircraft ejection seat (pictured) that thinks for itself is on display for the first time at Farnborough 2004. Ejection seat and escape technology manufacturer Martin-Baker is showing its Mk16E for the Lockheed Martin F-35 Joint Strike Fighter at Stand D3, Hall 4.

Currently in an advanced stage of development, the seat will provide an escape system able to eject pilots in the event of problems during short take-offs and vertical landings.

An on-board computer selects the best mode of seat operation by monitoring the aircraft's speed and altitude. This gives the pilot the best chance of survival in emergencies. And where the pilot is unable to react quickly enough to a rapidly developing crisis, an automatic ejection capability kicks in.

Hovering
If retained for production, this automatic system will eject the pilot if the aircraft departs from previously established parameters, during transition from conventional to vertical flight and vice versa, and while hovering.

The seat can be adjusted vertically and tilted to accommodate the size and weight of its occupant and has full life support. Its design also reduces the aircraft's weight and manufacturing costs.

Also on display at the stand are the US16LA seat for the Raytheon T-6A, and the K16K seat for the Korean-built KAI T-50.

by ISABEL LESTO - source: Flight International 19th July 2004"
_______________

http://www.martin-baker.co.uk/products/ ... --JSF.aspx

"SPECIFICATIONS - US16E - JSF
Auto eject system Active on STOVL variant only
&
HOW IT WORKS:
- Seat firing handle pulled/Auto eject initiated (STOVL only) causing seat initiation cartridges to fire"

VarkVet wrote:

spazsinbad wrote:To me IF is a BIG word.

Yaaa! … Either redesign it, or time change it at more frequent intervals if issues are surfacing!

That is one component you don’t want to try and save money on … I’m sure it’s one catastrophic drive shaft failure per aircraft it lets go in flight!

Or you talk about F136 ? If F135 failure .

svenphantom wrote:The question I am having is, Did it use AB or was it a mil power?

I suspect that F-35 need use AB to supersonic.
It's said that F-35A need more than 60s from 0.8M to 1.2M.
use the same time, F-16 can accelerate from 0.8M to 1.6M.
F-35's supersomic performance maybe as bad as F/A-18E/F.

spazsinbad wrote:popcorn, I don't have a subscription either however someone has posted this tidbit:

“DOD, Lockheed Agree On Redesign Of JSF Drive Shaft Critical To Marine Corps Plans

http://defense.iwpnewsstand.com/insider ... e=06242010

"The Defense Department and Lockheed Martin have agreed to a new design of a component critical to the Marine Corps’ variant of the Joint Strike Fighter — a drive shaft connecting the main engine to the vertical lift fan that will be incorporated into the F-35B if test flights in the coming months validate recent durability concerns.

On June 10, plans for a new drive shaft passed muster with government and contractor officials conducting a critical design review. They gave the green light to proceed with the production of the new component, which if necessary may be incorporated into Joint Strike Fighter aircraft built under the next production batch -- low rate initial production lot 4, according to a Lockheed official.

“Delivery of the first redesigned drive shaft for testing is scheduled for late 2010,” John Kent, a spokesman for Lockheed Martin, said in a written response to questions from InsideDefense.com.”

To me IF is a BIG word. Here is the link again:

http://defense.iwpnewsstand.com/insider ... e=06242010

Thanks a lot Spaz, very helpful.

seruriermarshal said: "Or you talk about F136 ? If F135 failure ." AFAIK the 'drive shaft connecting the main engine to the vertical lift fan' is common to both engines - so engines are not the issue in this instance.

spazsinbad wrote:seruriermarshal said: "Or you talk about F136 ? If F135 failure ." AFAIK the 'drive shaft connecting the main engine to the vertical lift fan' is common to both engines - so engines are not the issue in this instance.

I mean just about new drive shaft to old drive shaft .

apg77 wrote:

svenphantom wrote:The question I am having is, Did it use AB or was it a mil power?

I suspect that F-35 need use AB to supersonic.
It's said that F-35A need more than 60s from 0.8M to 1.2M.
use the same time, F-16 can accelerate from 0.8M to 1.6M.
F-35's supersomic performance maybe as bad as F/A-18E/F.

I suspect those numbers are a bit on the conservative side first of all, and the F-35 is capable of supersonic speeds at military power, at sea level. We'll have to wait and see what it can do at 35-45k feet.

In regards to a lift fan failure - You'd better have a quick reaction auto eject system in place when* that happens during hover. With 20K + thrust bellowing out at right angle to the aft fuselage at near-zero airspeed, that thing is gonna go into a somersault before you can say "Gulp!".

As far as the perfomance specs being 'conservative', does anyone remember any recent fighter program where the operational a/c top speed significantly exceeded public projections? Thought not...

BTW, the 'suspicion' that the F-35 will be supersonic on mil power at S/L is more accurately termed a 'fantasy'. Sea level supercruise...

JL

*Cuz you know its gotta happen when you're pumping the kind of horsepower found in a light frigate thru a lightweight shaft/tranny.

butters, the buzz is that sensors in engine and elsewhere monitor 'health' of system. When indications of impeding failure exceed a limit then 'auto eject'. Sure an extremely sudden catastrophic failure will not be good; that is the case in many other situations, also with any aircraft (that may or may not have predictive health sensors or other safety systems). You would guess I guess that the extreme situation described by you is the reason why such 'safety systems' exist. Bear in mind if one end fails then it is likely the other end will shut down to help prevent the dire situation described, helping 'auto eject'.

VarkVet wrote:

spazsinbad wrote:I have read that the drive shaft in STOVL flight is closely monitored by the automatic ejection system.

Not smart in my book as sensors are difficult to design and prone to failure!l

So are aircraft with complex propulsion systems.

VarkVet wrote:

spazsinbad wrote:I have read that the drive shaft in STOVL flight is closely monitored by the automatic ejection system.

Not smart in my book as sensors are difficult to design and prone to failure!l

You know what are also prone to failure? People.

How many pilots have died in functioning airplanes from G-LOC or being plain disoriented? An automated eject system, even though it might not be perfect, has an excellent chance of saving a lot of lives.

butters wrote:
As far as the perfomance specs being 'conservative', does anyone remember any recent fighter program where the operational a/c top speed significantly exceeded public projections? Thought not...

Do F/A-18F Rhinos hitting M1.84 in high speed trials in India count?