F-16XL

[Viper1031]

Figured I'd revisit this since they're putting out the J-8 Peace Pearl. It was never built, it never flew. At least the XL was built and flew. Can pretty well guess on weapon systems, block 30ish to block 50ish. If they can do Peace Pearl, someone could do the XL Viper

[F-2]

I think the plan was block 25-50ish but the two prototypes had F-16A avonics. Either way it would be easy to find. I always suggest this as a project for a new eager team.

[mkellytx]

The XL’s are very marginal as a module compared to say an F-20 which was a far more complete project.  The biggest issue of course is that both XL’s were maybe prototypes if not more demonstrators.  The airframes were re-worked A/B models, the avionics were analog C, later NASA equipped the GE engined XL with the digital FLCS, but programmed the code very conservatively as the structural analysis wasn’t done to see if the new control laws would overstress the airframe (like what happened to the F-14D).  There were also unresolved handling quality issues, oscillations in the transonic regime that drove some pretty bad Cooper-Harper ratings.

Had the XL been developed its timeline would have overlapped the block 40’s and 50’s.  So that’s likely what the avionics would have been. 

An argument for the XL would be that the aerodynamics of the platform are among the most measured and understood since NASA used it as a research platform for the High Speed Civil Transport and now uses the data to validate CFD code (Google search it, lots of technical papers).  The downside is the avionics were never developed on those two aircraft and there were unresolved handling qualities.

Personally, I like the sandbox quality of DCS and think it would be an interesting “what if”, but it’s questionable if there’s enough of that market to justify the expense of development.

My $0.02

Edited February 16, 2023 by mkellytx

[Viper1031]

On 2/16/2023 at 1:07 PM, mkellytx said:

The XL’s are very marginal as a module compared to say an F-20 which was a far more complete project.  The biggest issue of course is that both XL’s were maybe prototypes if not more demonstrators.  The airframes were re-worked A/B models, the avionics were analog C, later NASA equipped the GE engined XL with the digital FLCS, but programmed the code very conservatively as the structural analysis wasn’t done to see if the new control laws would overstress the airframe (like what happened to the F-14D).  There were also unresolved handling quality issues, oscillations in the transonic regime that drove some pretty bad Cooper-Harper ratings.

Had the XL been developed its timeline would have overlapped the block 40’s and 50’s.  So that’s likely what the avionics would have been. 

An argument for the XL would be that the aerodynamics of the platform are among the most measured and understood since NASA used it as a research platform for the High Speed Civil Transport and now uses the data to validate CFD code (Google search it, lots of technical papers).  The downside is the avionics were never developed on those two aircraft and there were unresolved handling qualities.

Personally, I like the sandbox quality of DCS and think it would be an interesting “what if”, but it’s questionable if there’s enough of that market to justify the expense of development.

My $0.02

 

Apparently someone thought the Peace Pearl was worth the expense. And even with it's flaws, the XL is a better aircraft than the Peace Pearl

[upyr1]

both aircraft raise the simple question, what does Eagle think is enough data for a module? I'll admit the F-16XL isn't the top of my wish list, but I'm not going to shoot it down either. My biggest objection to any protype request is simply what sort of data do we have available?

I don't know what systems were installed on the XL during testing nor do I know what were planned -and if there was any difference but I will say that if have enough data for the flight model and the avionics (either planned or installed) then why not?  

 

[mkellytx]

45 minutes ago, upyr1 said:

both aircraft raise the simple question, what does Eagle think is enough data for a module? I'll admit the F-16XL isn't the top of my wish list, but I'm not going to shoot it down either. My biggest objection to any protype request is simply what sort of data do we have available?

I don't know what systems were installed on the XL during testing nor do I know what were planned -and if there was any difference but I will say that if have enough data for the flight model and the avionics (either planned or installed) then why not?  

That’s exactly the problem with the XL.  The demonstrators had early C model avionics, one had a Pratt engine, the other had the GE, later upgraded to the -129.  The jet needed the higher thrust engine to make up for the higher weight.  Both originally had analog FLCS, the GE bird later got the digital FLCS with NASA.  The control laws were intentionally conservative as the requisite analysis was never performed to fully exploit the capability.  The flight test report still characterized unacceptable handling qualities that were never analyzed/fixed.  The XL’s role was primarily A/G interdiction with a late 80’s/early 90’s entry to service so Block 40/50 avionics was likely, although I haven’t seen anything definitive that says that.

The problem is there never was an XL built with Block 40/50 avionics, much less updated to the CCIP configuration which we have from ED.  While NASA detailed the aerodynamic performance characteristics like no other teen series fighter, the handling characteristics were never fully explored or fixed.  There’s a ton of data, really good data, but the XL is very much WIP.  That’s why I use marginal to describe it.