Northrop/McDonnell Douglas YF-23 and EMD F-23

[lantinian]

Most people quite logically assume that the YF-23 having somewhat bigger profile is larger and heavier. Also, that is was a more a concept demonstrator than a prototype with many parts from other aircraft. 

Approximately 50 percent of the YF-23 production model structures will be composites. The aircraft will be in the 55,000 pound weight class, according to Rooney

Quite the opposite seams to be true. Not only had YF-23 a more advanced internal structure but it was also lighter as a result. The F-22 as we know today is considered to be a 60 000lb + pound aircraft.

Another commom misconception is that the YF-23 will undergo a more radical change than the YF-22 from a prototype to production stage.

some subtle changes in configuration

is what says the YF-23 program manager.  I also think that making an airplane longer is easier and less troublesome than changing the wing sweep and the shape of the entire forward fuselage, as was the case with F-22

[KJ_Lesnick]

After reading, you can rename the thread 

I take it this is a what-if design?  If so, I'd change the nozzles (same shape but cover more of the top) to make a thrust vectoring design more like the F-22.

If they were using 2-Dimensional shock structures and mechanics like 1960's era fighters, that would be true. However, the ATF designs used three dimensional shock structures which offer greater pressure recovery and they also used other technologies, such as porous materials and possibly fluidic controls to manage their shock structures which offer the ability to control the inlet flow without mechanical controls, thereby maintaining their L.O. properties over the speed range.

I thought 2D shapes yielded better efficiency (at least with hypersonic waveriders -- but the same thing that would produce high pressure recovery would produce high lift on such a design)...

What's a fluidic control?  And what's L.O. properties?


Kendra Lesnick

[lantinian]

I thought 2D shapes yielded better efficiency

Cooling efficiency Yes, but trust efficiency - NO

What's a fluidic control?

Ability to change the direction of the exaust trust without moving parts. X-36 had such technology on it.

And what's L.O. properties?

Low Observable = Stealthy

[KJ_Lesnick]

Cooling efficiency Yes, but trust efficiency - NO

 

I would almost swear I read that the 2D design (with delta-wings, but the compression ramp was wedge shaped) produced lower overall drag...

So a highly-swept design is more efficient?

Ability to change the direction of the exaust trust without moving parts. X-36 had such technology on it.

Assuming that's not clasified, how the hell do they do that?

Low Observable = Stealthy

Thanks


Kendra Lesnick

[lantinian]

I would almost swear I read that the 2D design (with delta-wings, but the compression ramp was wedge shaped) produced lower overall drag...
So a highly-swept design is more efficient?

I think, this is actually quite simple geometry. A Circle will always have less circumference than a Rectangle for a similar area. So, if for any shape where the other types of drag are equal, the tube like shape will have less parasitic drag, as it exposes less area to the airflow. If 2D design were more aerodynamic and flight efficient, bullets would not had a round shape now would they? The main advantage of using 2D Nozzles is in heat management and better  easier LO integration with the rest of the design.

A highly swept design has nothing to do with the above argument.

Quote
Ability to change the direction of the exaust trust without moving parts. X-36 had such technology on it.

Assuming that's not clasified, how the hell do they do that?

I hope you run a google search before you asked that. If not try it and check one of the many articles on the subject. It's not rocket science but its not a short explanation either.

And please keep your questions relevant to the topic, or create another one after you have made the relevant search.

[KJ_Lesnick]

I would almost swear I read that the 2D design (with delta-wings, but the compression ramp was wedge shaped) produced lower overall drag...
So a highly-swept design is more efficient?

I think, this is actually quite simple geometry. A Circle will always have less circumference than a Rectangle for a similar area. So, if for any shape where the other types of drag are equal, the tube like shape will have less parasitic drag, as it exposes less area to the airflow. If 2D design were more aerodynamic and flight efficient, bullets would not had a round shape now would they? The main advantage of using 2D Nozzles is in heat management and better  easier LO integration with the rest of the design.

A highly swept design has nothing to do with the above argument.

Makes sense, but I specifically remember being told on hypersonic waveriders that the 2D shape results in less drag...   

[flateric]

Damn, this is YF-23 topic!

[Sundog]

I take it this is a what-if design?  If so, I'd change the nozzles (same shape but cover more of the top) to make a thrust vectoring design more like the F-22.

Northrop considered thrust vectoring for the YF-23, IIRC, but didn't go with it because the YF-23 met the maneuvering specs without them and they decided to go for more L.O. instead.

[SOC]

I take it this is a what-if design?  If so, I'd change the nozzles (same shape but cover more of the top) to make a thrust vectoring design more like the F-22.

Northrop considered thrust vectoring for the YF-23, IIRC, but didn't go with it because the YF-23 met the maneuvering specs without them and they decided to go for more L.O. instead.

The initial requirement had for thrust vectoring had to do with short field performance.  When the USAF dropped the short field requirement, Northrop deleted the TVC system.  However, both PAVs were built with nacelles and nozzles sized to take the TVC system.  Production aircraft would have had slimmer overwing nacelles.

[Sundog]

You're confusing thrust vectoring with thrust reversing. Thrust reversing is a kind of vectoring, but not the same thing. The thrust reversers the YF-23 would have had would have been ahead of the nozzle, I believe similar to how the F-15 SMTD's reversers were mounted, but on the top side only on the YF-23. That's why the production version would have had shorter, lower weight nacelles, compared to the EMD which had nacelles designed to fit them.

[flateric]

Wooahha! Current state of YF-23A PAV-1 as of May 2008. Magic weapons' bay doors are open
http://www.flickr.com/photos/erekose76/tags/northropyf23/
Pity that instead of taking at least good digital camera, guy had only damn communicator crappy stuff with him.

Anyone is nearby Dayton, ah?

[elider]

I live in Beavercreek, Ohio which is near the Museum. It looks like it is not yet on display. I'll try to get some pics .

[flateric]

It's in restoration shop...they offer Behind the Scenes Tours there...

Behind the Scenes Tours are regularly scheduled, free guided tours of the museum's restoration area. The museum shuttle bus transports participants to the restoration hangars, located on the historic Wright Field flight line in Area B of Wright-Patterson Air Force Base, about one mile from the main museum complex.

Behind the Scenes Tours are offered every Friday (some exceptions) at 12:15 p.m. Advanced registration is required, and registrations are currently being taken for tours through August 2008. Sign up early as tours may fill up quickly! Registration closes the Wednesday before the tour; however, a limited number of "walk-in" registrations are available on the day of the tour. No group reservations are accepted.

Participants must be at least 12 years old, and an adult must accompany those between 12 and 18. A current government-issued photo ID (i.e. driver's license) is required of all individuals 18 and over. Foreign visitors must present an original passport. For security reasons, all bags are subject to search, and backpacks, packages and large camera cases are not permitted on the shuttle bus.

To register, please call (937) 255-3286. Note: Individuals requiring handicapped accessibility should advise museum staff when registering.

Elider, I think that several thousands of YF-23 nuts will ask you for favor, with me being your field photographer for the Monino museum and all the MAKS shows for the next decade.

[elider]

You have more info on tours than I do. That info wilol be helpful. I'll try to get a tour soon. I may have to email the pics to someone for resizing.

[flateric]

You can upload original pics zipped to fileshare service like zShare.Net or Mediafire. If you can ask stuff to allow you shoot weapons bay inside (pretty sure that it's pristine empty of classified stuff now), it would be great.