Author Topic: Future mods  (Read 13150 times)

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Offline Sad Sam

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Re: Future mods
« Reply #15 on: March 13, 2011, 10:50:31 PM »
There are two meters in the roof of the bomb bay, one mounted forward of the centre of gravity and one mounted aft.  The forward meter measures positive "G" and the aft one negative.  There are (from memory) six windows in each meter which each count a different "g" loading (from 0.1 g up to 2 g I think - it's part of the lecky A/F servicing so I don't look at it very often.)

Each flight profile would have a different calculation, a high level transit has a different calculation to a low level training flight.  These days we only have two flight profiles which are low level display and transit.

After the aircraft has flown we take readings from the two meters and carry out a calculation according to the amount of "G" the aircraft has pulled.  Negative "g" consumes more of the fatigue life.
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Offline johnjosh43

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Re: Future mods
« Reply #16 on: March 13, 2011, 11:29:29 PM »
So in 50 years she's used up 253.05. 67 left so she should last for ages :-)
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Offline jangor

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Re: Future mods
« Reply #17 on: March 14, 2011, 08:04:29 AM »
Just done a quick calculation, and its 13.23849042 years left.......... :D  :D
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Offline scampton61

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Re: Future mods
« Reply #18 on: March 14, 2011, 10:29:18 AM »
Glad you're not my maths teacher  :lol:

You're forgetting the 14 years she spent on the ground, and (correct me if I'm wrong Sam) the finite fatigue total probably includes the FI that would be added by the leading edge modification.
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Offline Sad Sam

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Re: Future mods
« Reply #19 on: March 14, 2011, 05:34:09 PM »
Also several "cat 3" repairs in there (cat 3 is either a civilian company working party or a visit from the gods that were Abingdon MU, also previously @ North Luffenham) so unfortunately it is not as simple a calculation as you may think.  Also in that fifty years she spent a lot of time up at high level where the air is nice and smooth and now we are down in the weeds, the VDF calculated their fatigue consumption @ about 2 FI per year in 2009 we consumed about 9FI (if you have a piece of string, how long is it?).  There was a good reason why in 1984 the oldest jet in the fleet had the lowest hours and the most life left in her.

Finite fatigue is the total authorised life of the airframe, the mods have to be carried out at the intervals specified by the manufacturer "Mod 2221 will need to be carried out @ ?", yeah sorry about that but it's in the F700 and I don't have that with me.  Suffice to say we have a serviceable jet and now we just need some money to fly her.
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Offline Intake

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Re: Future mods
« Reply #20 on: March 18, 2011, 09:22:06 PM »
Quote from: "Sad Sam"
There are two meters in the roof of the bomb bay, one mounted forward of the centre of gravity and one mounted aft.  The forward meter measures positive "G" and the aft one negative.  There are (from memory) six windows in each meter which each count a different "g" loading (from 0.1 g up to 2 g I think - it's part of the lecky A/F servicing so I don't look at it very often.)

Each flight profile would have a different calculation, a high level transit has a different calculation to a low level training flight.  These days we only have two flight profiles which are low level display and transit.

After the aircraft has flown we take readings from the two meters and carry out a calculation according to the amount of "G" the aircraft has pulled.  Negative "g" consumes more of the fatigue life.

Here's an Image of the meters taken this week when I asked Sam about them having read this post.
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Offline fil cad

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Re: Future mods
« Reply #21 on: August 10, 2011, 09:11:11 PM »
I dont know how true this is but i heard that whilst in the VDF days these meters were somehow disconected for what ever reason, and when realised they were reconected and a higher FI was calculated to balance the scales? :o
« Last Edit: January 01, 1970, 01:00:00 AM by Guest »