Performance take offs

[reheat]

Hi all,
Just a quick question for those in the know.
What is the reason for Typhoons doing performance take offs from Coningsby, (not QRAs),and why are they only carried out occasionally?

[Ghastly Whisper]

because they can?

[reheat]

because they can?

Really useful reply.
Thanks.

[jamesg23]

One reason is they are giving someone a back seat ride.

[reheat]

And to avoid overflying villages so get up quick noise soon goes

Not with full reheat.

[martmpf]

Presumably, pilots need to practice all aspects of operational performance. So a QRA call would not be the first time.
I think I have read somewhere that a full burner performance take off does increase engine maintenance cost, particularly on blade coatings and almost certainly increases airframe stress. So it would not be "normal".

[Vulcanone]

The 41 Sqn special did it today, and kept on going in burner till he was a wee spot in the sky. Several other single seaters also did it, so I would suspect currency as one also popped his chute on return.

[reheat]

Presumably, pilots need to practice all aspects of operational performance. So a QRA call would not be the first time.
I think I have read somewhere that a full burner performance take off does increase engine maintenance cost, particularly on blade coatings and almost certainly increases airframe stress. So it would not be "normal".

Thanks. That makes a lot of sense now.

[Ghastly Whisper]

because they can?

Really useful reply.
Thanks.

yea, was very tired and it seemed funny at the time, sorry

[Ghastly Whisper]

Presumably, pilots need to practice all aspects of operational performance. So a QRA call would not be the first time.
I think I have read somewhere that a full burner performance take off does increase engine maintenance cost, particularly on blade coatings and almost certainly increases airframe stress. So it would not be "normal".

I dont see how that is possible, lighting the burners is a normal operation, the fan blades dont care if the burners are lit or not. The airframe itself is designed to take a lot more punishment than a performance take off. We are talking about an aircrafty that routinely pulls a lot of G. The limiting factor is the seat to stick interface.

[Malcolm]

Presumably, pilots need to practice all aspects of operational performance. So a QRA call would not be the first time.
I think I have read somewhere that a full burner performance take off does increase engine maintenance cost, particularly on blade coatings and almost certainly increases airframe stress. So it would not be "normal".

I dont see how that is possible, lighting the burners is a normal operation, the fan blades dont care if the burners are lit or not. The airframe itself is designed to take a lot more punishment than a performance take off. We are talking about an aircrafty that routinely pulls a lot of G. The limiting factor is the seat to stick interface.

One(Two?) of the primary life ratings for engines is/are full power cycles and duration. After each Typhoon flight, data is downloaded from the pilots 'brick' into a maintainance system which analyses all the key parameters recorded during the flight. Longer in reheat = lower engine life. If the pilots 'brick' fails, then the aircraft gets grounded till the data can be extracted and decoded from the aircrafts crash recorder. This can take several days.

One of the findings of the investigation when a Qantas 747 ran off the end of the runway in Singapore (or was it Malaysia) was that company rules were partly responsible because they said pilots were to avoid using reverse thrust on landing wherever possible because it uses a high power cycle which therefore reduces engine life, and hence costs.

[Seahornet1]

... Longer in reheat = lower engine life...

I can understand that it will shorten the life of the reheat, tailpipe and nozzle components, but why would it affect the engine itself? Are 'non-reheat' take offs conducted at less than full power on the engine core...?

[toom317]

Why do some folk get a raging hard-on about seeing a so called "performance take off" , and then have to post that they've seen one?

[Mark]

Why do some folk get a raging hard-on about seeing a so called "performance take off" , and then have to post that they've seen one?

Enthusiasm perhaps??

[reheat module]

I seem to recall a similar question to the original post being asked before; I think(?) the reply given is that it was part of the Student's Training profile, and at a set part in the syllabus, the PTO was included in the schedule.

[reaper493]

A performance take off is flight 2? in the training syllabus i believe, to show the student pilot the outright performance of the jet.

Obviously once qualified pilots have to keep current so you do see them from time to time, plus they happen for other operational reasons, such as when the Typhoons were stationed at Northolt for the Olympics due to runway length and populated surrounding area.

Tuesday seem's to be the most common day for it.

I once saw a flight of three 29sqd jets go up, all doing performance take offs. That was a nice sight!

Mike

[PR9]

Uses a lot of fuel.

Austerity you know.

[Dazza37]

... Longer in reheat = lower engine life...

I can understand that it will shorten the life of the reheat, tailpipe and nozzle components, but why would it affect the engine itself? Are 'non-reheat' take offs conducted at less than full power on the engine core...?

Reheat take-offs use max engine rpm, which increases turbine inlet temperature, turbine temp, combustion temp, heat and wear of all bearings/moving components etc, and a host of other engine wear parameters, all of which reduces engine life between major overhauls...

-Dazza

[3051Howe]

Performance takeoffs are a tactical option as well. Stick it on its backside and get above the limit heights of surface to air missile systems etc as quickly as possible. Typhoon's are now the RAF's mainstay of fast jet capability with the wind down of the Tornado and the F-35 a long way away from operational approval by the RAF so are most likely to end up in theatres that require them to be able to get out of the way of surface to air stuff, they are most vulnerable to that during landing/take off

[Seahornet1]

... Longer in reheat = lower engine life...

I can understand that it will shorten the life of the reheat, tailpipe and nozzle components, but why would it affect the engine itself? Are 'non-reheat' take offs conducted at less than full power on the engine core...?

Reheat take-offs use max engine rpm, which increases turbine inlet temperature, turbine temp, combustion temp, heat and wear of all bearings/moving components etc, and a host of other engine wear parameters, all of which reduces engine life between major overhauls...

-Dazza

So, "yes" to my last question then...? I'd always assumed that a non-reheat take-off would also require maximum engine rpm; I didn't realise the Typhoon had quite so much power to spare!