YF-23 Versus YF-22: Why did USAF choose the F-22? 

YF22_YF23_13_SM_1267828237_2250.jpg

Jim Smith was working in a technical liaison role in the British Embassy in Washington during the high stakes competition between the YF-22 and YF-23 to provide USAF with its next super fighter. In this role, he attended the YF-22 roll-out, and also wrote an analysis of the two aircraft.

Save the Hush-Kit blog. Our site is absolutely free and we have no advertisements. If you’ve enjoyed an article you can donate here. At the moment our contributors do not receive any payment but we’re hoping to reward them for their fascinating stories in the future.

Why did USAF choose the F-22 and was this the right choice? 

My analysis observed the obvious differences in size, planform and shaping for two aircraft designed to meet the same requirements. From material available at the time, it was evident that the performance and range requirements were as demanding as the signature requirements, exceeding those of the F-15 while having a signature of the order of 1% of that aircraft.

I concluded that the YF-23 design looked to have been optimised for low signature, and that to achieve this, the wing design had been compromised, resulting in a less efficient wing design, and ending up with a larger, heavier design. At the time Aviation Week reported a wing area of 950 sq ft compared to 830 sq ft for the YF-22.

The high-risk of thrust vectoring 

The use of the 2-D vectoring nozzle, integrated with the FCS is an essential enabler for the YF-22, as this allows the agility and manoeuvre requirements to be met with a smaller airframe. At the time, this represented a significant risk for the design, as no current US exemplars existed although thrust-vectoring experimental systems had been flown using external paddle arrangements, incompatible with a low-signature solution. Apart from low-speed manoeuvre, thrust vectoring can also allow supersonic trim drag and signature to be reduced, as control surfaces can remain un-deflected and in line with the wing to reduce head-on RCS.

how-thrust-vectoring-works.jpg

The YF-22 looked to me to have been designed to meet the manoeuvre and range requirements, and then shaped, packaged and integrated to have the lowest signature that could be achieved with the selected configuration. The fuselage shaping and planform appears less sophisticated than that of the YF-23, but I judged at the time that Lockheed had the know-how to meet the signature requirements, and, in delivering a smaller, lighter solution, stood well-placed in the competition provided the 2-D thrust-vectoring nozzles could be integrated successfully with the fcs.

In making this judgement, I was aware that there is a strong correlation between mass and cost at a given technology level. Although the technology decisions made by the designers were somewhat different, the smaller, lighter Lockheed design was likely also to come in at a lower cost (at least as viewed through the lense of this cost-mass correlation).

Was this the right decision? It is of course, impossible to know. But in my judgement, USAF expectations do appear to have been met by the developed F-22 Raptor.

Two Up

hh.png

“Two Up is a collection of anecdotes and stories drawn from our more than 50-year experience of photographing, flying, analysing, designing and generally working with aircraft. The 26 episodes in the book cover everything from schoolboy expeditions to photograph aircraft in England; to Ron’s visit as Westland’s Chief Future Project Engineer to Russia and Poland to examine their helicopter industry; my learning to fly aerobatics in the Chipmunk; Ron’s flight to Oshkosh on Concorde; and many more.

Lockheed Martin F-22 Raptor Wallpapers (6)

Two Up Down Under focuses on a visit Ron made to Australia to enjoy an aviation and photographic road trip around the Riverina, leading to our visit to the Australian Antique Aeroplane Association’s fly-in at Echuca, Victoria. There is something for everyone in here, whether you are interested in Volkswagen kombis, recreational and antique aircraft in Australia, flying, photography or classic cars. In his later career, he was a well-regarded analyst working primarily on Land Systems for BAe Systems. Both Ron and I have been private pilots. He has owned a number of interesting aircraft, including a 1938 Tipsy B, and is also a winner of the Dawn to Dusk Trophy. My flying experience highlights include Chipmunk aerobatics and flying recreational aircraft in Australia.”

Save the Hush-Kit blog. Our site is absolutely free and we have no advertisements. If you’ve enjoyed an article you can donate here. At the moment our contributors do not receive any payment but we’re hoping to reward them for their fascinating stories in the future.

Want to see more stories like this: Follow my vapour trail on Twitter: @Hush_kit

Have a look at How to kill a RaptorAn Idiot’s Guide to Chinese Flankers, the 10 worst British military aircraftThe 10 worst French aircraft,  Su-35 versus Typhoon10 Best fighters of World War II top WVR and BVR fighters of today, an interview with a Super Hornet pilot and a Pacifist’s Guide to Warplanes. Was the Spitfire overrated? Want something more bizarre? The Top Ten fictional aircraft is a fascinating read, as is The Strange Story and The Planet Satellite. The Fashion Versus Aircraft Camo is also a real cracker. Those interested in the Cold Way should read A pilot’s guide to flying and fighting in the Lightning. Those feeling less belligerent may enjoy A pilot’s farewell to the Airbus A340. Looking for something more humorous? Have a look at this F-35 satire and ‘Werner Herzog’s Guide to pusher bi-planes or the Ten most boring aircraft. In the mood for something more offensive? Try the NSFW 10 best looking American airplanes, or the same but for Canadians. 

 

both_yf_23_prototypes__and_a_yf_22_chasing_by_fighterman35-da0k8pm

Advertisements

One comment

  1. Mike

    Some thoughts on this topic.

    Stealth: Due to the exposed fan blades (see picture on the link below) the YF-23 would have had worse VLO characteristics from certain angles particularly from the front. This would have been redesigned in production models but that would most likely affect the YF-23’s performance advantages over the YF-22.

    https://yf-23.net/technical.html

    Range: Arguably the biggest advantage of the YF-23 over the YF-22. However, estimates vary from 750 nautical miles all the way to 900 nautical miles. The YF-22’s radius is not all that bad coming in at just below 700 nautical miles

    Maneuverability: Arguably the biggest advantage of the YF-22 over the YF-23. Even Northrop’s executives admitted that the YF-22 was the more agile of the 2. However this was not just simple low speed air show maneuverability. A critical requirement was supersonic maneuverability where the traditional control surfaces loose control. This is really where TVC comes into play. Northrop’s answer was to have an over-sized pelican tail configuration, tho effective, I doubt they would have the same results as the YF-22’s TVC.

    Speed: Though commonly said to be faster, YF-23 test pilot, Paul Metz said that they never flew beyond Mach 1.85. And he said if they kept doing it they would run out of canopies due to excessive canopy cracking at those speeds. So its safe to say that even though the YF-23 was capable of very high speeds, its canopy design prohibited it from going at that speed.
    Officially the YF-23’s top super cruise speed was Mach 1.62 while the YF-22 was Mach 1.58. So its faster but only slightly.

    Weapons: Here is one overlooked aspect of the program. the YF-23 only carried 5 missiles, (3 AMRAAMs and 2 Sidewinders) where as the YF-22 carried 8 missiles

    In conclusion. Stealth and Speed were particularly tied with both designs, the YF-23 had a very slim and negligible advantage in speed . Range was the only area where the YF-23 seemed to have a clear advantage. The YF-22 had clear advantages in Maneuverability and Weapons capacity.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s