Forum: X-planes

I don't know how much you guys like "vs" threads, but I thought this would be a fun idea. It's two similarly-sized, similarly-powered, highly maneuverable experimental aircraft pitted against each other.

Yes, I do realize that the X-29 and X-31 do not have weapons, but for the sake of this thread, let's put some on them. Let's say that both aircraft are armed with one 20mm M61 Vulcan cannon carrying 500 rounds of ammunition. They do not carry missiles.

Since the X-29 was developed from the F-5 Freedom Fighter, let's say that it has been equiped with the radar and avionics equipment that the latest model F-5 has carried. In order to make things more even, let's say that the X-31 is carrying the same radar and avionics equipment as the X-29.

In order to make the scenario a bit more interesting, we'll pit four X-31s against four X-29s. The fight starts off at BVR, but will have to close in to WVR because the only weapons that the aircraft has are their cannons. Both teams of aircraft start at 500 miles per hour at 30,000 feet heading towards each other from 100 miles distance (is this reasonable?). All aircraft are fully fueled. The conditions are fair weather during daylight hours.

Since both aircraft feature maneuverability enhancements (the X-29 has FSW and the X-31 has TVC), this fight depends a lot on the comparative capabilities of these features (as well as speed and altitude performance). Let's assume that ALL of the pilots have full intimate knowledge of their own aircrafts' capabilities AND that of the opposing aircrafts' capabilities.

X-29 Source:
http://www.nasa.gov/centers/dryden/news/FactSheets/FS-008-DFRC.html

X-31 Source:
http://www.nasa.gov/centers/dryden/news/FactSheets/FS-009-DFRC.html

X-29 Characteristics:
Length: 48.1 feet
Wingspan: 27.2 feet
Weight: 17,600 pounds (this variant will be heavier due to the cannon)
Engine Thrust: 16,000 pounds
Maximum Operational Ceiling: 50,000 feet
Maximum Speed: Mach 1.6
AoA Limitations: 45 degrees (excellent control), 67 degrees (limited control)

X-31 Characteristics:
Length: 43.33 feet
Wingspan: 23.83 feet
Weight: 16,100 pounds (this variant will be heavier due to the cannon)
Engine Thrust: 16,000 pounds
Maximum Altitude Capability: 40,000 feet
Maximum Speed: Mach 1.28 (might be higher)
AoA Limitations: Up to 70 degrees.

Since this is a 4 v 4 match up, this offers the possibility of differing survival statistics than in a 1 v 1 match up. For example, we could say that all four X-29s are destroyed and three X-31s go down in the process, or that the X-29s destroy all of the X-31s with no losses. Depends on how much of an advantage you feel one aircraft type has over the other.

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intresting...this is tuff. I would say the X-29 but I didn't understand much. All I know is that some guy/girl is going to post something that puts this post in the shadows. I say the one X-29 makes it out of the fight with little ammo and that's it. maybe some one can change my mind. I hope any way.

Hmmmm.... I would have to go with the X-31 simply because of its manuverability over the X-29, Since its a up-close, personal, in your face kinda fight with guns only, manuverability (as well as pilots skill) should be the major contributing factors for a victorious outcome. Two Cents

But hey, I'm just a crew chief, what do I know about dogfighting Shrug

X-31 spanks the X-29s....

Sorry, the MASSIVE maneuverability advantage of a 3d thrust-vectoring engine cannot be overcome.

Consider this...

Forward Swept Wings (FSW) are designed to give lower tran-sonic drag, not higher manuverability. True the FSW wing does generate better low speed lift than an aft sweep, but I doubt the FSW alone would gain enough advantage over a TV equipped aircraft to even come close.

FSW jets may have better low speed handling than any other aircraft, but a TV jet would have post-stall handling that the FSW wouldn't have. Simply stated, when the TV jet is still turning/flying, the FSW jet would be falling/dying.

Quote:

In air-to-air combat tests, two X-31's flew a total of 103 mock dogfights against a NASA F/A-18 and had a victory ratio of nearly 10 to 1.

I'd lay my money on a TV aircraft over a non-TV aircraft any day! (10 to 1 is fairly good odds)

Keep 'em flyin' Thumb

TEG

OK! you've all changed my mind I'll go with the X-31. The way you guys are talking, why even put the X-29 up against it why not a more suitable fighter.

I thought somewhere I read that the X-29 was able to beat one or more of the teen-series aircraft in combat maneuvers as well (I'm sorry that I can't be more specific, but this is a fairly vague memory). Does anyone know if the combat maneuvering potential of the X-29 was ever investigated vs. the teen series?

X-31, this paper might give you some insight to the internal debate.

.

Kryptid wrote:

I thought somewhere I read that the X-29 was able to beat one or more of the teen-series aircraft in combat maneuvers as well (I'm sorry that I can't be more specific, but this is a fairly vague memory). Does anyone know if the combat maneuvering potential of the X-29 was ever investigated vs. the teen series?

In theory or practice? I wouldn't imagine that the agency managing the X-29 program would jeopardize the demonstrators in ACM with any active fighters. I too would have to give the edge to the X-31 in this matchup.

Kryptid wrote:

In order to make the scenario a bit more interesting, we'll pit four X-31s against four X-29s. The fight starts off at BVR, but will have to close in to WVR because the only weapons that the aircraft has are their cannons. Both teams of aircraft start at 500 miles per hour at 30,000 feet heading towards each other from 100 miles distance (is this reasonable?). All aircraft are fully fueled. The conditions are fair weather during daylight hours.

Hello everyone, some thoughts for the fun of it:

I) Kryptid put only vulcans on the jets, so the engagement makes sense WVR with a max range of roughly 4000ft (PGU ammo). My opinion would be that standard Head-on BFM (or any neutral set-up, butterfy,LAB,etc) is the way to go, because any greater separation doesn't make any difference.

II) No need for 4vs4, 1 vs1 would do it. No tactics to employ (WWII gun fight Very Happy

).

III) Speed-wise, 450K would be better (thinking like a viper Wink

).

IV) When employing a gun, there are two "choices": [CAUTION: pretty simplistic approach] tracking shots & snapshots.
You are tracking someone when you are in his plane of motion, speed and with the proper lead to take the shot; snaps on the contrary, can be taken whenever you can place your reticles on the adversary, even momentarily (sole consideration: range). Super-manouverability helps mostly for snaps and tracking defence (jinks).
So, the X-31's massive manouverability advantage (which would be LETHAL in a heater scenario) loses some significance. Take into account X-29's low speed handling qualities and things ain't that clear. Cool

P.S. If we had a heater (AIM-9L) scenario, I would bet my jet on the X-31 Wink

Cheers, John.

Right On JP. Guns only from a butterfly. I like it. This reduces pretty much everything to mano v mano.

Remember, 20MM is a launch and leave all aspect weapon (admittedly a brainless one). Its' range is a function of muzzle velocity plus any velocity (closure) imparted to it by the aircraft doing the shooting.

So for the sake of the discussion, let’s assume the butterfly turns into a series of head on passes (pure closure) and that the thrust vectoring, post stall maneuvering X-31 “goes for it” on the first head on pass, playing to his supposed strength. The range of his 20MM is now solely a function of muzzle velocity.

I, in my X-29, being aware I cannot “out-nose-point” him, make only my first turn a bat turn and pass him close aboard on the first one.

From the butterfly at 450K, both of us are probably too close to use the gun this pass, and I keep my speed up and gain some separation for purposes of executing what will necessarily be, thanks to him, another head on pass. He may now be thrust vectoring like crazy, just pointing at me, maybe even post stall, and muzzle velocity is all he can impart to his 20MM.

I however make a relatively big sweeping optimum turn outside of 4000 feet and come back at him at the speed of stink.

The range of my 20MM is muzzle velocity + the speed of stink, and I open fire based on this and break off the head on pass in some optimum plane for E-M before I get within his “muzzle velocity only” range. Think of a strafe panel.

Maybe I hit him the first time, maybe I don’t, but I do the same thing each time until I do or he changes his tactic, possibly playing to my strength.

Thrust vectoring, post stall maneuvering, etc. (Cobras), these are all primarily defensive options. It’s nice to have available, but if someone insists on going slow with it in a gunfight, admittedly they definitely have proven whose more maneuverable, and it would probably be a nice gesture if the other guy assured it was written on their epitaph that they were “more maneuverable”.

Theoretically, all else equal, this could work no matter what weapon you’re using, as long as both guys are using the same one and you can get out of range of it on the first pass. You may just have to get further away.

From my experience, this is kind of like fighting A-10's with the F-4.

regards, OL

Of course the

X-31!! you people heard of the herbst maneuver???

Well Kryptid and all... why not just test out this little 'what if' scenario then! Cool

http://www.youtube.com/watch?v=S6ZGaERQEg0

Forum: X-planes

Rockwell-MBB X-31 vs. Grumman X-29