Technical Northrop F-18L question please

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Pioneer

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G'day once again gents!

I hope this is in the correct part of forum! :eek:

I have a question if I may pertaining to the defunct Northrop F-18L.
Im putting together a 'Alternative Backstory' at another forum.
Could someone far more knowledgeable on these matters please give me insight as the difficulty (or hopeful ease) in which the General Electric F404-GE-100 turbofan engine, as used in the Northrop F-20 Tigershark, could have been incorporated into the F-18L in say 1981-82?
Im attempting to add operational commonality between the F-18L and F-20, as a 'high-low mix' package for the RAAF's Mirage III replacement.

I know that the F/A-18C/D incorporated up-rated F404-GE-402's, but in truth Im ignorant as to what modifications were needed/done to achieve this!

As well as giving commonality, this would also in essence give the F-18L an additional 907kg (2000Ib) thrust!
Add to this the F-18L's approx 1130-1360kg (2500-3000Ib) reduction in weight off the F/A-18A overall weight, Im envisaging the RAAF not wetting its pants as readily with the proliferation of the Flanker within the region!

Looking forward to your reply and input

Regards
Pioneer
 
The various F404 variants aren't all that different. Trying to harmonize down to the same dash version is probably unnecessary.
 
Thanks for the reply TomS!
So you don't see much benefit in matching the same variant to the two different aircraft?
By my own admittance, I don't know the intricate details of different variants of the F404, but would there be much difference in the maintenance of the F404-GE-400 and the F404-GE-100?


Regards
Pioneer
 
I'm not a F404 expert, so "trust but verify". It's likely that the differences were external to the gas path. These might be:

- Wiring and harnesses.
- Pneumatic "plumbing" - a dual engine installation would have plumbing and valves to allow crossbleed of high pressure air from a running engine to a non-running engine for start purposes.
- Physical mounting provisions. An engine destined for a twin engine aircraft can have the thrust mount installed on the 3 or 9 o'clock position to interface with the keel structure (as in the F-18). On a single engine aircraft, the thrust mount would be at the 12 o'clock position as there is no centerline keel structure as such.

HTH!
 

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The 1st F-20 had a 16,000lb F404-GE-100 engine, effectively an off the shelf -400 with minor installational changes for single engine use. The 2nd and 3rd F-20s had slightly uprated 17,000lb engines and the 4th (uncompleted) prototype was going to get 18,000lb to demo the planned production configuration. It is likely that these were effectively special "one-offs" either run hotter (with reduced life) or with specific changes like those applied to the -402. A "production" 18,000lb F404-100 would therefore just be a -402, modified for single engine installation.

F404 was deliberately conservative in thrust to weight compared to F100 for cost, reliability and lifespan reasons. You could have had a higher thrust version earlier in time, but at a cost in engine lifespan.

In essence therefore I don't think you need to posit using -100s on the F-18L for higher thrust or commonality. You could in your fictional account have common 18,000 lb F404-GE-101 and F404-GE-401 engines, or F404-GE-102 and F404-GE-402 engines, whatever you want.
 
Thank you all for your feedback and input!

Regards
Pioneer
 

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