Anyone have any later references to F-35B weight growth since this one in March 2012? Tah.
F-35A Discussed in Australian Federal Parliament Committee 16 March
2012
"...Dr JENSEN: You were talking about weight not being an issue. The problem is that the JSF is already over the 28,948 pounds from the planned amount not to be exceeded. It has already gone over the not-to-exceed weight. There are some problems in the system that have been identified, such as structural issues and so on, that will need to be fixed. That will ultimately result in not only more weight for the direct fix but more weight to make adjustments to the centre of gravity and so on. This is obviously going to adversely affect performance. Is this figured into your calculations for the future at all?
Air Vice Marshall Osley: I do not believe your statement about the F35 being overweight is correct. I do not have the figures here, but the latest estimate that I have is that it is around 90 pounds or so under its maximum weight. The conventional takeoff and landing aircraft last exceeded its allowable weight back in late 2004.
Dr JENSEN: The SWOT analysis?
Air Vice Marshall Osley: Yes. There was a very extensive program that went through and modified many, many parts in the aircraft to reduce the weight. They took several thousand pounds off the aeroplane and it has since been under the not-to-exceed weight and it continues to be under the not-to-exceed weight as of the latest reporting I saw yesterday at the JSF Executive Steering Board.
Dr JENSEN: It has certainly crept up. As I said, my info is that it has already gone over, but anyway—
Air Vice Marshall Osley: That is not correct....
...Senator FAWCETT: Weight margins on the aircraft: in terms of length of useful life of an aircraft, modifications, weight margin and also power available are critical factors, and my reading of available literature indicates that there is a very small weight margin available. Could you comment?
Mr Burbage: Weight is most critical on the short take-off, vertical-landing jet. That is the one that has the toughest requirement for taking off from and landing on small ships. You saw in the movie that we did that, this year. We predict the weight on that airplane to grow at about three per cent per year throughout the rest of the test program and it could grow some more throughout its life if more capability that has substantial weight goes on the airplane. If you look at the STOVL jet and you look at our weight charts, which you are more than welcome to see, we have now gone two years without any weight increase on the STOVL jet, and that is while accommodating engineering changes to the doors, which we have replaced with heavier doors, and other changes that were made to the airplane. We manage the weight very tightly on that airplane—for good reasons, because it needs to be. The other two airplanes are not as sensitive to weight. We are actually probably several thousand pounds away from the first compromise of the performance requirements of those two airplanes. We do, however, manage the weight very tightly on all three airplanes. The metric that we look at is when the weight growth curve levels off, that means your design has stabilised. You are no longer making lots of changes to the design. All three airplanes are now in that level-off phase. The best one is the STOVL where you can go back and see that we have not increased any weight at all in a full two years.
Senator FAWCETT: So having reached that steady state, you are saying you are some thousands of pounds away from—
Mr Burbage: On the non-STOVL jets.
Senator FAWCETT: So the conventional take-off and landing—
Mr Burbage: The key performance requirements that are weight-dependent have large margins still ahead of them. On the STOVL the key performance parameters are much tighter to the weight, because it is more physics than aerodynamics."...
...Dr JENSEN: You said quite explicitly that in the last two years the STOVL version had seen no weight increase.
Mr Burbage: That is correct.
Dr JENSEN: The QLR charts seem to indicate differently. I am referring to the quick look review that was conducted last year.
Mr Burbage: I could show you the chart if I had my computer here. We were actually planning to.
Dr JENSEN: I will show you the chart. I am afraid it is a bit small, but you can see there is January 2010 and there is January 2012. Clearly there has been a weight increase.
Mr Burbage: This increase right here is a ground rule change, not unlike other ground rule changes—when the weight of the electro-optical targeting system was added in, it is just a step function increase. If I bring this down and I measure that point directly back, it goes back two years to intercept that curve there.
CHAIR: Can I just pause there. For the benefit of Hansard, it is impossible to put up on record what you are talking about.
Dr JENSEN: I will get a copy of that chart and provide it so that it can be tabled.
Air Cdre Bentley: That quick look report is a US official use only chart. As such, it has not been released and therefore for us to comment specifically on it is quite out of the ordinary in this type of environment.
Dr JENSEN: Okay. In terms of the STOL weight, would it be true to say that the empty weight now is over NZW?
Mr Burbage: I do not know. I can find out for you. I will take it for the record and provide an answer to you.
Dr JENSEN: If you could take that on notice then.
Mr Burbage: The STOL weight has been very stable and the airplane is meeting all of its performance requirements, so I am not sure what the question is...."
House of Representatives Committees ? Parliament of Australia