F-16.net

Elite 1K Joined: Aug 02, 2006 Posts: 1003 Status: Offline

The weight numbers available from official documents are a little conflicting...

In the F-35 statistics document from Lockmart's website (last modified 07/07/2006), its weight was given as 26,500 lbs / 12020 kg.
http://www.lockheedmartin.com/data/assets/12792.zip

The Program Brief from Sep 2006 on the other hand has the following charts:-

The empty weight was quoted here as 29,036 lbs (~13.2 tons) with a big "*" next to it whose meaning is unclear.

This is a chart (from the same document) shows the weight of the components of the F-35 when they actually weighed them vs when they calculated the weight. Basically, you have the airframe and systems that goes into it but not the engine (propulsion). When the document was prepared, the total weight came up to 13,496.1 lbs. Because the vehicle was not complete this represented 61% of the total weight were it to be a finished vehicle.

If 13,496.1 lbs = 61%, then 100% = 22,124.8 lbs.

If this is the weight of an engineless but otherwise complete F-35-AA-1, there is no way it'll weigh 13.2 tons. Why? Because for the aircraft to weigh 29,038 lbs in all, the engine will have to be ~6,913 lbs. Thats ridiculous and would have made the F-135 the porkiest and lowest performing engine in modern times. 43,000 lbs / 6913 lbs = 6.22. That kind of thrust to weight ratio is worse than an F100 or F414. We expect the F-135 to be a 9~10:1 thrust-to-weight class engine. The F100-PW-229 is ~3750 lbs for instance with a thrust to weight ratio of ~7.7:1. If the F135 is ~4,400 lbs then the vehicle will should weigh in at 26,525 lbs or ~12 tons flat -- inline with the specifications given by Lockmart on their website!

BTW, we are talking about the AA-1 here which does not benefit from the 2004 redesign which resulted in a subsequent weight loss of ~1 ton for the B version and significant reductions for the A and C.

Now, I have more questions than answers here. So don't look at me to say I know, or I think I know, what the actual weight is. But I believe that it is prudent to say that the production representative F-35A will probably weigh between 12 and 13.2 tons, and it has the potential to be lighter than we think it is.

F-16.net Sponsor

F-16.net Editor Joined: Sep 23, 2003 Posts: 2862

We will know more once they get to the phase of testing that has more war related equipment in it. The current test bird even has some Navy specific stuff in it now. They tested fuel dumping not long ago, which the CTOL will not have.

I'd do a weight and see on this DW. Very Happy

Elite 1K Joined: Aug 19, 2004 Posts: 1092

elp wrote:

I'd do a weight and see on this DW. Very Happy

*rim shot*

Enthusiast Joined: Sep 27, 2006 Posts: 67 Status: Offline

Quote:

The empty weight was quoted here as 29,036 lbs (~13.2 tons) with a big "*" next to it whose meaning is unclear.

29,036 lbs could be it's *empty equipped* weight... there are also two numbers for the F-22 going around, one around 44,000 and one around 40,000... I think the former is the empty weight with weapons, and the latter is the true empty weight. It may be the same for the F-35.

F-16.net

Forum: F-35 Lightning II

The F-35A lighter than we think?