G Limits

[Brian Abraham]

A question regarding the effect of underwing stores and how does it impact on the aircraft permissable G you can pull. And what if stores are loaded asymetrically? Also rolling G limit. Any F-4, Buc, Harrier, Hawk etc guys with an answer?

[Milt]

Check the thread "Light aircraft down north of Bathurst"

[Brian Abraham]

Milt, thats the reason I ask. Get the gen from people with hands on experience of types other than the one I flew.

[GlosMikeP]

A question regarding the effect of underwing stores and how does it impact on the aircraft permissable G you can pull. And what if stores are loaded asymetrically? Also rolling G limit. Any F-4, Buc, Harrier, Hawk etc guys with an answer?
Try putting an inquiry on the flight test community. You'll get a good mix of flight test aircrew and engineers there, all with MAR (CA Release as was) experience. Bound to be someone who can answer with authority.

[Tarnished]

The heavier an aircraft is the more 'damage' will be transfered to the airframe for a given 'g'. With appropriate design reserves the aircraft will have a 'design mass' at which maximum 'g' is allowable. Above this mass there will be restriction on the maximum allowable 'g'. This mass comes from all sources; the aircraft, its fuel, and its stores. Traditionally this has been the pilot's job to both know the limits for the configuration and fly the aircraft in a manner to avoid exceeding the limit. (Ask for a comment from any Tonka pilot). With the introduction of Typhoon and its CFH (Carefree Handling), pilot observed limits will be a thing of the past.

So the short answer is 'yes' stores affect the max allowable g to a greater or lesser extent which varies from aircraft to aircraft and improves through the generations.

T

[gashman]

"With the introduction of Typhoon and its CFH (Carefree Handling), pilot observed limits will be a thing of the past"

Not sure about that one. I haven't flown Typhoon, but I remember the "Typhoon Roadshow" doing the rounds and trying to drum up more support from some RAF Stations and they stated that in certain stores configs, the pilot will still be required to observe G-lims. It is certainly possible to have flight software limit Gz with changes in stores, but you certainly pay for it. I don't think that the budget covered this, but I stand to be corrected.

[Pontius Navigator]

hi Gashman you still on exchange?

[Lone Kestrel]

gashman,

Not quite right – Typhoon care free handling will be available for all store groups but like all ac if you always pull to the max G limit you will eventually run out of fatigue. Typhoon will have to manage its FI like all other ac if it is to last its full in service life– Carefree handling wont stop the FI usage it just wont allow the pilot to over G.

[gashman]

Lone K, thanks for the update. I presume that this means that there will be a false G limit to fly to, which means that the pilot will not be able to fly the jet in a carefree manner?

Pontius Navigator, yes I am

GM

[mbga9pgf]

gashman,

Not quite right – Typhoon care free handling will be available for all store groups but like all ac if you always pull to the max G limit you will eventually run out of fatigue. Typhoon will have to manage its FI like all other ac if it is to last its full in service life– Carefree handling wont stop the FI usage it just wont allow the pilot to over G.

I was under the impression that Eurofighter had a carbon-fibre composite spar, and as such Fatigue was not a factor? I am aware Composites can become brittle once exposed to UV light, but for the eurofighter example, I would suggest (and may possibly be wrong here) that eurofighter does not have a fatigue life as such. :8

[RAF_Techie101]

Not quite on thread topic, but applause goes to the OCU pilot who managed to pull 4.5G upon landing on wednesday night... And what does he write in the 700...? 'Suspect Heavy Landing'...

You'd think a few beers would be in order, at least seeing as that was the second one we'd had that night...

Vent over...:8

[lightningmate]

mbga9pgf,

Wrong I am afraid. Typhoon does have a fatigue life and it was very carefully specified against how long the jet is required to serve.

lm

[Lone Kestrel]

lm’s spot on. Typhoon FI is based on a 25yr in service life and therefore it will be subject to the same FI limits at legacy ac. It may have a carbon-fibre composite spar but it still has bits bolted on in the normal way and the 100 FI clearance will be subject to an incremental release depending on how the fatigue test bed behaves.

[raytofclimb]

RAF Techie101.......

Why do engineers expect aircrew to buy beers even after making a genuine mistake?

1. OCU= he's learning to fly the jet. A twenty ton fighter(!) not a Hawk.
2. Night= he can't see the runway until his under powered landing lights get close enough to ease it out of the darkness.
3. Did you buy the aircrew any beer last time you made a mistake?
4. Did an engineer [I]ever[I] buy a pilot any beer after making a mistake?

I have done a spectacularly heavy landing in the same type of jet due to being just back from holiday, rather heavy and with 8 live missiles on board- parts of which were written off. Since the definition of "heavy" was some arb rate of descent at touchdown I too snagged the jet for a "suspect heavy landing". And yes...... I humbly bought the beer on that particular occasion.

What's good for the Goose..................

(edited for assumptions; you're talking about an F3 since 56 sqn is at Kinloss. Either way, it still goes)

Ray

Thread creep; soz