YF-24? Very interesting .pdf

reply to post by cavtrooper7


It's really really complicated. A blunter nose tends to not heat as much at higher speeds. It was originally thought that to go supersonic you had to have a sharp, narrow aircraft and nose. But as they learned more they found that it wasn't quite as important, and a slightly rounder nose gets better subsonic performance, and still goes supersonic just fine. There are a bunch of really complicated math formulas that show the different nose types and their performance. My brain tends to go "WTF IS THAT?!" when I see them though.

I think I'm probably going to need a little help translating this one. The technical aspects of it are....complicated. So if you guys want to tackle it by section, and translate a section that you're good at then I'd greatly appreciate it. Otherwise I'm going to be translating for days here.

reply to post by Zaphod58

Brigadier General Joseph Lanni retired from Wright-Patt in 2011. His bio was changed and the mistake regarding the YF-24 in his flight information, has been deleted.

www.af.mil...

reply to post by Violater1


Yeah, I had a feeling they would.

What I found really interesting is that there is great detail about the Model-24F, and how they tested it, and that it was a joint USAF/USN program. If you read the abstract before the actual paper, there's one line, buried towards the bottom, that says something to the effect of "A separate test aircraft was developed to test the suitability of carrier operations". I know there's at least one USN black project currently flying, so it makes you go "hmmm".

reply to post by Zaphod58


Perhaps it is like the F19 debacle.

The YF-24 reference was deleted from Lanni's bio in the wake of all the interest it generated on discussion forums like ATS. It was not removed because it was a mistake or typo. A similar situation occurred several years earlier when Col. Dennis Sager's bio surfaced with the information that in the early 1990s he had been handpicked to command a “Classified Flight Test Squadron” that led a "classified prototype aircraft" called the YF-113G “from design to first flight.” It also said that he was first Air Force pilot to fly the YF-113G.

Sager had, like Lanni, been a Red Hats pilot so there was some question as to whether the YF-113G was a foreign type. After all, several other YF-113 designations (i.e. YF-113A, YF-113B, YF-113C, and YF-113E) have been used for various models of MiG-17, MiG-23, and other foreign aircraft, and Red Hats pilots refer to their aircraft as “classified prototypes.” At least one other member of that squadron besides Sager is known to have flown the YF-113G, but the words “from design to first flight” suggest an altogether new type of aircraft.

Originally posted by Zaphod58
I think I'm probably going to need a little help translating this one.

I got yo' back, bro.

Section 1 is a pretty basic explanation of what the idea is. Hooray everybody.

Section 2 is where they define all the crap they want to test. They clearly want to reduce or eliminate the vertical stabilizers and replace them with some other, stealthier control method. They have a bigass table of all the stuff they could possibly think of, and then they narrow it down to 6 options. I can explain more into detail if anyone wants to know what some of their concepts are if it is not clear from how they name it. Interesting part of the section:

The baseline aircraft chosen for this effort was the Boeing-developed advanced tactical aircraft designated the Model-24F, which is...

This aircraft was not designed for this experiment. It was designed prior, and for some other purpose. This report (written by Boeing) just happens to use the airframe in its investigation. They already had this aircraft designed and potentially built before this report was ever filed.

Section 3 is obviously more in detail. 3.0 specifically states that they will test to see if Spit Ailerons, Chine Strakes, or Rotating Tails will provide the yaw control needed for stable flight. It also appears they may have played with 2-axis TVC. Sec 3.1 lists off the various types of flight that the solutions would be tested at and the various aircraft configurations associated with them. At this point all the testing appears to be simulated, as they go through testing whether the aircraft would be stable (read: intact at the end of flight) without vertical tails. It does not appear so. Sec 3.2 declares the engineering parameters of the simulation, and the result is on Page 17 where it shows the lift coefficient based on angle of attack. It also shows the AOA limit, and the bad things that happen after you go past the limit. The pitching moment coefficient tells you if the aircraft wants to automatically pitch up or down on you as you change the lift coefficient, and you can see that above the AOA limit line it wants to stall out and pitch down on you.

Sec 3.3 really gets into the meat of the testing software and process. Page 21 lists all the configurations of solutions that they will test. 3.3.1 talks about some of the advanced behaviour they program into the simulation, I won't explain it better unless someone really wants me to. Sec 3.3.2 through 3.3.4 goes into what translates as a fly-by-wire system, taking control demands and turning them into control surface maneuvers. Sec 3.3.5 explains how the signals from sensors are filtered and passed as data. Sec 3.3.6 explains how the system deals with maneuver demands that can cause conflict with flight envelope constraints, or how it acts when it runs out of control surfaces to move.

Sec 3.4 gets into the tasty, tasty results. The overview explains the levels of pass vs fail for various portions of the test.

Sec 3.4.1 talks about the Takeoff and Approach configuration, with the results summarized by table on Page 32. The study concludes that the rotating tail is the best solution here.

Sec 3.4.2 talks about a Power-On Departure Stall. The table is on Page 36 and, again, concludes that the rotating tail is the best solution.

Sec 3.4.3 tests the aircraft characteristics in ACM. Table is on Page 41, the rotating tails are the best and they seem to enjoy dumping on the split ailerons and the chines.

Sec 3.4.4 tests the aircraft in a low-level penetration flight. Table is on 47, and they conclude that the rotating tails are very effective.

Sec 3.4.5 tested the aircraft at max load, that is high altitude, high speed, and high weight. Results on 51. Yadda yadda yadda.

Sec 3.4.6 checks the solutions at supersonic speed. In general it shows that the rotating tails produce the best results.

They note during the last part of 3.4.6 that the split ailerons had poor success because they did not produce enough aerodynamic power to replace the vertical stabilizer, and the chines were unsuccessful because they mostly do work at high angles of attack which were not tested.

What would a rotating tail look like?I am learning to be a concept artist so it would behoove me to know.

Originally posted by cavtrooper7
What would a rotating tail look like?I am learning to be a concept artist so it would behoove me to know.

This is a difficult question to answer because their system lacked any really clear diagrams, but the best I can tell you is that they removed the vertical stabilizer and replaced it with something like the back of the YF-23.



Instead of having a movable flap at the rear of the stabilizer, they make it so the whole stabilizer moves. Obviously by increasing the movable area, you decrease the total area that you need. For this particular test they fixed those stabilizers at 20 degrees dihedral (similar tilt to the YF-23), but they posited that the system could be able to change that angle. A system that allows you to rotate the whole control surface and actively adjust it to whatever dihedral (or, potentially, anhedral) angle the situation demands could be very flexible indeed.

reply to post by Zaphod58


Maybe the YF-24 was the McDonnell Douglas/General Dynamics A-12 Avenger II.

en.wikipedia.org...






Cancelled in 1991......

C...

reply to post by Darkpr0


Thanks for that. I thought I was going to have more down time today, and still be stuck in Vegas, but of course that got tossed, because they didn't want to swap the load off us like I told them to on Monday. I still can't believe all the RCS data that they put in it just from skimming through it.

reply to post by Zaphod58


I KNEW I had seen or read YF-24 at some point in time. I dug up the book, Blank Spots on the Map by Trevor Lately and oddly enough had bookmarked the relevant section. While investigating black projects he used a technique he called RESUMINT, or resume Intel, by looking at test pilots resumes and matching time periods with numbers of known and still black aircraft flown. Lanni is someone he specifically talks about. Small world!

Originally posted by steppenwolf86
reply to post by Zaphod58

 

I KNEW I had seen or read YF-24 at some point in time. I dug up the book, Blank Spots on the Map by Trevor Lately and oddly enough had bookmarked the relevant section. While investigating black projects he used a technique he called RESUMINT, or resume Intel, by looking at test pilots resumes and matching time periods with numbers of known and still black aircraft flown. Lanni is someone he specifically talks about. Small world!

Stupid auto correct, the author is Trevor Paglen, not lately...

Darn it's been done on the movie "Steath",that is what the F37 used .but hey at least I know my hardware.

reply to post by Zaphod58


Hey Zaphod58, first of all this is a fascinating thread! As an enthusiastic amateur with no insider knowledge and a desire to steer as far from conspiracy theories as possible, I generally preface my few posts with an "apologies if this is already common debate..." type opening line, but I figured I'm among friends so here goes:

Is it just me, or is the aircraft concept depicted in the pdf of the Boeing Model-24F (i.e. the one using 1998 technology) virtually identical to the Boeing MRF-24X concept? The difference being that the latter uses (according to the image) uses 2003 tech with an IOC of 2010, has no vertical stabilizers or tail planes and has twin engines. Otherwise the planforms are strikingly similar! Clearly, the MRF-24X appears to represent a step beyond the Model-24F and closer to that of the F/A-XX concept. Of course, whether either design ever came to anything beyond engineering papers and miniatures is another question.

Here are the drawings for comparison:

Model-24F: i.imgur.com...

MRF-24X: forum.keypublishing.com...

Again, sorry if I've either got the wrong end of the stick or am reproducing common reference material, but thought it was interesting and might add something to the debate!

reply to post by SneakyPete


That's very interesting. I hadn't seen the second design before. I knew that the Model-24 used aspects of what they were going to put into the F/A-xx. Which makes it very interesting considering that the -24 had an IOC of the early 2000s. Great link, very interesting. Thanks for that.

reply to post by Zaphod58


Awesome stuff, glad the link was helpful and interesting! I also fired it to Dave Majumdar at The DEW Line to see if it'd be of interest to him too. Will be interesting to see if anything comes of it!

Another interesting PDF, dealing with the porous forebody and strakes.

ntrs.nasa.gov...

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Colonel Joseph A. Lanni is Commander, 412th Test Wing, Air Force Flight Test Center, Edwards Air Force Base, Calif. He is responsible for the airframe, power plant, and avionics development, test, and evaluation of manned and unmanned aerospace systems, the U.S. Air Force Test Pilot School, and operation of all Edwards Air Force Base test facilities and ranges.

Colonel Lanni was commissioned in 1980 following graduation from the U.S. Air Force Academy, Colorado Springs, Colo. Assignments throughout his career include Director of the F/A-22 Combined Test Force, Air Force Flight Test Center, Edwards Air Force Base, Calif., as well as operational fighter pilot, aggressor pilot, experimental test pilot, and commander of our nation’s only classified flight test squadron. Additionally, he has served as a staff officer at the Air Force and Joint Chiefs of Staff level. A command pilot, he has more than 4,300 flying hours in over 70 different types of aircraft including the F/A-22 and numerous classified prototypes.

EDUCATION:

1980 Bachelor of Science degrees, Engineering Mechanics and Mathematics, U.S. Air Force Academy, Colo.
1985 Squadron Officer School, Maxwell Air Force Base, Ala.
1991 Master of Science degree, Aerospace Engineering, University of Florida, Gainesville, Fla.
1993 Air Command and Staff College, by correspondence
1996 Air War College, by correspondence
1998 Master of Science degree, National Security Strategy, National War College, Ft. Lesley J. McNair, Washington, D.C.
2001 Defense Systems Management College, Ft. Belvoir, Va.
ASSIGNMENTS:

June 1980 – September 1980, Structural Engineer, Air Force Armament and Test Laboratory, Eglin Air Force Base, Fla.
October 1980 – September 1981, Student, undergraduate pilot training, Laughlin Air Force Base, Texas
October 1981 – February 1982, Student, Lead-in Fighter Training, Holloman Air Force Base, N.M.
March 1982 – September 1982, Student, F-4D Replacement Training Unit, 308th Tactical Fighter Squadron, Homestead Air Force Base, Fla.
October 1982 – May 1986, F-4E aircraft commander, wing instructor pilot and flight safety officer, 335th Tactical Fighter Squadron, Seymour Johnson Air Force Base, N.C.
June 1986 – June 1988, Instructor pilot and wing standardization and evaluation flight examiner, 57th Fighter Weapons Wing, 64th and 65th Aggressor Squadrons, Nellis Air Force Base, Nev.
July 1988 – June 1989, Student, United States Air Force Test Pilot School, Edwards Air Force Base, Calif.
July 1989 – June 1992, Experimental test pilot, instructor pilot and command standardization and evaluation flight examiner, 3247th Test Squadron, Eglin Air Force Base, Fla.
August 1992 – January 1994, Assistant operations officer, 6513th Test Squadron, Edwards Air Force Base, Calif.
February 1994 – June 1995, Operations officer, 413th Flight Test Squadron, Edwards Air Force Base, Calif.
July 1995 – June 1997, Commander, Classified Flight Test Squadron
July 1997 – June 1998, Student, National War College, Ft. Lesley J. McNair, Washington, D.C.
June 1998 – June 2000, Joint Warfighting Analyst, Force Structure, Resources and Assessment Directorate (J-8), the Joint Staff, Pentagon, Va.
June 2000 – June 2001, Chief, Global Analysis Division, Air Force Studies and Analyses Agency, Director for Command and Control, Deputy Chief of Staff, Air and Space Operations, Headquarters United States Air Force, Pentagon, Va.
July 2001 – December 2002, Vice Commander, Detachment 3, Air Force Flight Test Center, Las Vegas, Nev.
December 2002 - May 2004, Director, F/A-22 Combined Test Force, Edwards Air Force Base, Calif.
May 2004 – present, Commander, 412th Test Wing, Edwards Air Force Base, Calif.
FLIGHT INFORMATION:
Ratings: Command pilot, parachutist
Flight Hours: More than 4,300
Aircraft flown include: F-4C-E, F-5E, F-15, F-16A-D, F-14, F-18, HH-60G, F/A-22, YF-24

MAJOR AWARDS AND DECORATIONS:

Defense Meritorious Service Medal
Meritorious Service Medal with 4 oak leaf clusters
Air Medal
Aerial Achievement Medal with 2 oak leaf clusters
Air Force Commendation Medal with oak leaf cluster
Joint Service Achievement Medal
Air Force Achievement Medal
OTHER ACHIEVEMENTS:

Top Academic Award, F-4 Replacement Training Unit, 1982
Top Graduate, United States Air Force Flight Safety School, 1985
Distinguished Graduate, Squadron Officer School, 1985
Distinguished Graduate, Aggressor Weapons School, 1986
Distinguished Graduate, United States Air Force Test Pilot School, 1989
Jabara Airmanship Award, 1990
Flying Magazine Aircrew of Distinction, 1991
Conducted first flights of two classified prototype aircraft
EFFECTIVE DATES OF PROMOTION:

Second Lieutenant, May 28, 1980
First Lieutenant, May 28, 1982
Captain, May 28, 1984
Major, May 1, 1992
Lieutenant Colonel, December 1, 1996
Colonel, March 1, 2001
(Current as of May 2004)

 

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Originally posted by SneakyPete
Of course, whether either design ever came to anything beyond engineering papers and miniatures is another question.

Oh, and at least one of them did. I'm pretty sure they went with the more conventional Model-24F design though. I don't recall hearing that it didn't have vertical fins, but I might be wrong.