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Can someone explain F1 to me?


Bozon

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The Mirage F1 always struck me as the oddball in the Dassault lineage. Out of the Mystere IV, Super Mystere, Mirage III, Mirage F1, Mirage 2000, Rafael, it is the least “pretty” one - not that it is ugly, but the others are exceptionally pretty.

In terms of design, it is easy to see its Mirage III ancestry though it underwent significant modifications - actually, it looks like someone took apart a Mirage III and then tried to put it back together without the instructions… Which is fine, but then the Mirage 2000 went back to the basic Mirage III shape. Why is that?

In terms of performance I read it was a straight upgrade from the Mirage III in pretty much every way. I alway thought of it as the contemporary of the F-4 Phantom, but it is actually closer to the F-14/15 years. Could it compete with them? Or the F-16A?

TL;DR

1. Why did Dassault divert from the delta without horizontal tail in the F1 and then reverted back to the pure delta in the M2000?

2. Is the F1 the peer of the early F14/F15, or is it the last of the previous generation fighters (basically an odd looking Mirage III on steroids)?


Edited by Bozon
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“Mosquitoes fly, but flies don’t Mosquito” :pilotfly:

- Geoffrey de Havilland.

 

... well, he could have said it!

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To make a long story short, the Mirage F1 came from an attempt to fixing the Mirage 3/5s landing speed (which is inherent to a delta); one of the proposed versions was called the Mirage F2, and another swing-wing one was the Mirage G. The Mirage F1 was basically a lighter, less complex, cheaper version of that, and obviously if you base your design on some sort of swing wing you need to leave the pure delta concept behind.

The reason why Dassault (and others...) went back to the delta wing design is the introduction of FBW. The delta wing has all sorts of advantages, particularly for transonic and supersonic flights, but those advantages are mitigated if you need your plane to be stable. With FBW allowing for relaxed stability designs, it's very attractive to go back to a delta configuration. It's no coincidence that most 4th gen high performance fighters designed from scratch with a full FBW system do feature some sort of delta wing (the F-16, Mirage 2000, Rafale, Typhoon, Gripen, Tejas, J-10, off the top of my head), and out of all those all but the Viper are either pure delta or delta canard (which to brutally simplify things is a refinement on the pure delta idea) concepts.

Performance wise, it's hard to tell without flying it but I'd say it sits somewhere in between what we expect for 3rd gen performance (like e.g. the F-5 or Mig-21) and 4th gen. It's definitely not a peer of the Tomcat and Eagle because those were designed as bigass air superiority fighters carrying a long range radar, while the entire Mirage family is all about being light weight, relatively cheap but capable aircraft, much like the F-104, F-5 or F-16. In that sense, it's probably somewhat comparable to an early block Viper, except a bit worse (no FBW, less power available, etc) overall. Keep in mind that for the time, the Viper's BFM performance was sensational.

edit: clarified the initial bit, turns out I misremembered and the swing wing was another design, but for similar reasons.


Edited by TLTeo
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Thanks @TLTeo I did not know that F1 was derived from a variable wing design - that does explain a lot in how the F1 looks. Trying to imagine it with such a wing, it must have been very similar looking to the Mig-23.

So we can call Mirage F1 a 3.5 generation fighter. That was unfortunate to these planes (F1 and Mig-23 for example) that within just a couple of years the leap to gen 4 fighters made them obsolete. The Mig-23 was proved to be significantly inferior to the F-16A and F-15 over Lebanon in 1982.

“Mosquitoes fly, but flies don’t Mosquito” :pilotfly:

- Geoffrey de Havilland.

 

... well, he could have said it!

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Eeeeeh fighter generations are badly defined anyway. Even within 3rd generation - is a 1958 USAF F-104A, with a glorified gunsight for radar and only two AIM-9Bs, really that similar to a ~1990 Italian Air Force F-104S with AIM-9L, Selenia Aspide BVR missiles, some semblance of look down/shoot down capability and on-board IFF? I would argue that the Mirage F1 is one of the most modern 3rd gen fighters, just like the Tomcat is in many ways the least modern 4th generation fighter.

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On 11/19/2021 at 3:36 AM, Bozon said:

The Mirage F1 always struck me as the oddball in the Dassault lineage. Out of the Mystere IV, Super Mystere, Mirage III, Mirage F1, Mirage 2000, Rafael, it is the least “pretty” one - not that it is ugly, but the others are exceptionally pretty.

In terms of design, it is easy to see its Mirage III ancestry though it underwent significant modifications - actually, it looks like someone took apart a Mirage III and then tried to put it back together without the instructions… Which is fine, but then the Mirage 2000 went back to the basic Mirage III shape. Why is that?

In terms of performance I read it was a straight upgrade from the Mirage III in pretty much every way. I alway thought of it as the contemporary of the F-4 Phantom, but it is actually closer to the F-14/15 years. Could it compete with them? Or the F-16A?

TL;DR

1. Why did Dassault divert from the delta without horizontal tail in the F1 and then reverted back to the pure delta in the M2000?

2. Is the F1 the peer of the early F14/F15, or is it the last of the previous generation fighters (basically an odd looking Mirage III on steroids)?

 

It's a late 3rd gen jet fighter, and incorporates a lot of features you would see on those jets designed at the time. Still turbojet, not yet turbo fan. Includes Stability augmentation systems, auto slats and flaps for manuvering and to shortening take off and landing distance, but no FBW though. This was also around the time where a lot of countries were concerned that their planes would have to potentially operate from damaged or modified runways or dirt fields, so more robust landing gear and again the changes in the wing and controls to allow for shorter takeoffs and landings. Incorporation of more multi-role aspects then just the intercept mission and the inclusion of radar guided missiles, and radars that could have at least limited shoot down capability. The desire to have an aircraft that could do those things and be relatively cheap with the technology they had at the time was why they went with the design elements of the F1, and as a result sacrifice some transonic, and high alt performance with the delta wing

What you got then was a capable, maneuverable, affordable jet that could basically do most of what a late model F4 could do, but cheaper and with way less maintenance attached. As for it's looks i'm partial to the delta designs myself, but I find there are a lot of unflattering pictures of the F1 out there. The landing gear extended make it look insectoid and many late versions had the fixed fuel probe, which takes a lot of time to grow on you, however in flight the F1 is a nimble little dart and has some good lines

 

 

va7ex74ywm651.jpg


Edited by CrazyGman
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  • 2 weeks later...

The F1 is effectively a Mirage III with a conventional tail and trapezoidal wing. It provides solid performance data on why most aircraft still have conventional tails and don't have pure delta wings. The trapezoidal and/or clipped delta wing dominates US designs, which is a compromise between a delta and a swept wing. The F1 outperforms the Mirage III in almost every possible way despite having a very similar fuselage and engine due to both its conventional tail and its swept wing which is very close to the trapezoidal design used by many other Mach 2 fighters. Tail-less delta wings are great for supersonic interceptors like the F-106 and Mirage 2000. They are not the best option unless top speed is the primary consideration.

On a tangent, the F-104A is not a 2nd gen fighter in any way shape or form. The F-104 was the US equivalent to the MiG-21, but with even less drag and more power. It is a Mach 2+ fighter with tremendous acceleration and climb performance. The F-104 is to the F-4 as the F-16 is to the F-15: single engine and two engine versions of the same tech level. If Lockheed had not crippled the F-104 with the small wing, it could have been a great WVR air superiority fighter in Vietnam to counter the MiG-21 and it would have had the option to carry more ordnance as a multirole fighter. Lockheed waited too late to realize that with its "Lancer" program.

 


Edited by streakeagle

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I am not sure the Mirage F1 has a trapezoidal wing. It is definitely a swept wing jet.

Also, it is not the in same gen as the F-14, 15 and 16. The F-1s first flight dates back to 1966 whereas the F-14’s was in 1970, the F-15’s was in 1972 and the F-16´s was in 1974. There is a generational gap in tech.  between 1960s fighter jets and their 1970s successors.

i doubt the F-1 is the equivalent in performance of even a first gen F-16. It is probably a counterpart to the Mig-23 (first flight in 1967) in terms of performance, though it might be more nimble. It is also contemporary with the Viggen (first flight in 1967 too).

Besides the Viggen, I can’t recall the existence of any US or otherwise western fighter jet that sits between the F-104/F-4/Mirage III/Lightning and the F-14/15/16/18. 

 

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1 hour ago, Leviathan667 said:

I am not sure the Mirage F1 has a trapezoidal wing. It is definitely a swept wing jet.

Exactly. It's a swept wing, which is precisely what the "F" stands for (flèche - arrow; similar to "Pfeilflügel" in German [lit. arrow(ed) wing]).

The F1 shall best be compared to contemporaries, which mostly is the MiG-23. The F1 is an incremental step between the Mirage III/ 5 family and the Mirage 2000 family. It didn't replace the MIII, but it really replaced the Super Mystère and the Vautour (IIRC).

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So ein Feuerball, JUNGE!

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Interesting how the F14 is apparently considered as 4th gen.  I always previously considered the “peak” of 3rd generation design, as it has no fly by wire.

 

As for middle ground between the F4 and 4th gen F16etc, does the Tornado F3 count?  I got the impression that it was fast and made a good interceptor, but really wasn’t that great as a dogfighter


Edited by Mr_sukebe

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3 hours ago, Mr_sukebe said:

Interesting how the F14 is apparently considered as 4th gen.

It has lots of 4th gen characteristics regardless of FBW - excellent dog-fighting performance, good BVR missiles, good look down/shoot down radar (for its time). In fact, when it was introduced it was arguably the best BVR fighter in the world, easily better than early F-15As and any Foxbat variant. DCS just gives you a warped perspective on the comparison with the F15/16/18, because the Tomcat (and particularly the variants we have) received comparatively fewer updates than the modern Viper/Hornet ED went for. A better comparison to those aircraft we have would be the F-14D, which is a whole leap ahead of the A/B. Speaking of FBW, there are a few 4th gen aircraft that don't necessarily use it - early Fulcrums for example, but the flight control systems in the JF-17 and AMX are also hybrid rather than full FBW systems.

The Tornado is definitely a 4th gen platform regardless of the variant - and unlike the Tomcat it's been updated very significantly over its lifetime. But honestly...the ADV should have not existed imo. I don't see what that aircraft does, that an updated Phantom with better avionics and radar doesn't (like the ones Germany operated). It definitely wasn't a good dogfighter.


Edited by TLTeo
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On 12/5/2021 at 8:13 AM, Mr_sukebe said:

Interesting how the F14 is apparently considered as 4th gen.  I always previously considered the “peak” of 3rd generation design, as it has no fly by wire.

 

As for middle ground between the F4 and 4th gen F16etc, does the Tornado F3 count?  I got the impression that it was fast and made a good interceptor, but really wasn’t that great as a dogfighter

 

FBW controls doesnt define a generation of fighter although they show up with 4th gen.  MiG-29A-S, F-15A-E are not FBW either.  Tornado F3 is a compromise.  THe design is for a penetrating low level jet.  Has one engine tuned for low level and one for high altitude, but it is FBW.  Complete trash in a turning fight.   F4s should be able to handle it in a dogfight.  Great radar though once it finally showed up- served a good portion of its career without a radar.   

VF-2 Bounty Hunters

 

https://www.csg-1.com/

DCS F-14 Pilot/RIO Discord:

https://discord.gg/6bbthxk

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  • 1 month later...

Generation labeling is largely mood. What is primarily driving combat effectiveness and capability are the avionics, sensors, weapons etc. Many designs still in service and in production as of today originate from the 1970s/1980s, but if you compare todays F-15EX, F-16 Blk 70 etc. to their ancistors from the 1970s all they have in common is the designation and general aerodynamic design. Everything else is leaps and bounds ahead. We have seen generations of cockpit display, computers, radars etc. being integrated over the past 40 years. To put an F-15A into the same generation as an F-15EX is ridiculous. It could be said that there has been a new generation every 10-15 years. And yes the evolution was progressive rather than interruptive. 

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FBW is a means of control-signal transmission and has by itself nothing to do with relaxed stabilty characteristics. Those are just a fancy additional feature enabled by FBW architcture and flight control computers.

The F1 (as well as the M III/ M5) does have FBW control augmentation channels. Pitch and yaw are primarily controlled in FBW with a mechanical backup. Roll is transmitted mechanically, unless in autopilot.

Quoting the F1CZ flight manual:

grafik.png

 

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9 minutes ago, Bremspropeller said:

FBW is a means of control-signal transmission and has by itself nothing to do with relaxed stabilty characteristics. Those are just a fancy additional feature enabled by FBW architcture and flight control computers.

Yes, that is what I said. FBW allows for relaxed stabilty designs, but that doesn't mean that anything with FBW is a relaxed stability designs (looking at you, Airbus airliners). If A then B doesn't mean that if B then A.

9 minutes ago, Bremspropeller said:

The F1 (as well as the M III/ M5) does have FBW control augmentation channels. Pitch and yaw are primarily controlled in FBW with a mechanical backup.

You are confusing stability augmentation systems with a full FBW system. Those two are not the same. Going by your definition the F-5, Mig-21, Tomcat and Viggen (to name a few aircraft in DCS) would also be FBW aircraft which they absolutely are not. Even some variants of the G-91 had stability augmentation systems, and that was designed in the 50s...


Edited by TLTeo
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9 minutes ago, TLTeo said:

You are confusing stability augmentation systems with a full FBW system. Those two are not the same. Going by your definition the F-5, Mig-21, Tomcat and Viggen (to name a few aircraft in DCS) would also be FBW aircraft which they absolutely are not. Even some variants of the G-91 had stability augmentation systems, and that was designed in the 50s...

I'm not confusing anything. I never said "full FBW system". The augmentation and control-transmission channels in the Mirages are dual-purpose. See the F1CZ AFM-excerpt above and the M IIIO flight manual excerpt below:

grafik.png

FBW is a means of control-command transmission and this is true for AFCS-commands or pilot-commands likewise.

 

This is what happens when the pitch-channel trips on you at high Q (footage slowed down significantly) - Project Sageburner.

 

Quote
Hite had already survived two horrific Navy carrier-based bomber accidents, bailing out of an AJ Savage that had lost its vertical fin and an A3D Skywarrior after an explosion severed its aft fuselage. Unfortunately, he and Felsman had no chance to escape this one. The Navy investigation attributed the crash to an unsuspected pitch-damper failure, the slowness of the existing pitch-trim system, Felsman's abrupt last-moment maneuver to line up on the record course, and the susceptibility of the F4H to Pilot-Induced Oscillation (PIO) at transonic speed and low altitude. PIO occurs when the airplane’s dynamic response to an externally generated (e.g. turbulence) pitch change matches that of the pilot’s response to it. If both airplane and pilot then react, again simultaneously, to the larger than expected pitch change, hell’s-own roller-coaster ride results. If the pilot doesn’t take himself out of the loop, i.e. let go of or not move the stick, the result could be an overload of the airplane’s structure.
 
When I joined McDonnell in 1966 as a flight test engineer fresh out of college, I was shown the then closely held movie clip of the inflight breakup of the first Sageburner. The pitch excursions didn’t seem particularly large but within a few seconds and about three cycles, ended with the airplane disintegrating at 14 gs, well above its design structural limit, and the engines flying out of the debris headed down course

Source: https://thanlont.blogspot.com/2016/01/in-memory-of-ensign-raymond-hite-jr.html

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I think we're just arguing over semantics. You're calling any stability augmentation system "FBW" (which by extension means that most 3rd gen aircraft would fall under that label) , I'm saying those are very different technologies and shouldn't be dumped in the same box. Let's just agree to disagree I suppose.

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47 minutes ago, TLTeo said:

I think we're just arguing over semantics. You're calling any stability augmentation system "FBW" (which by extension means that most 3rd gen aircraft would fall under that label) , I'm saying those are very different technologies and shouldn't be dumped in the same box. Let's just agree to disagree I suppose.

Only if it meets FBW criteria. FBW is a means of control-signal transmission. Just like Fly-by-Light is.

What is commonly assumed and implied to be FBW (as in "FBW aircraft") is an extension of the original meaning.

So ein Feuerball, JUNGE!

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Quote

Can someone explain F1 to me?

I believe it involves driving strange looking cars around a closed lap of tarmac road, for a somewhat tedious amount of time…

YMMV, but I suspect rallycross or WRC may prove far more entertaining for four wheel aficionados…

For the real deal google Isle of Man TT

😉


Edited by rkk01
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Only if it meets FBW criteria. FBW is a means of control-signal transmission. Just like Fly-by-Light is.
What is commonly assumed and implied to be FBW (as in "FBW aircraft") is an extension of the original meaning.

Sure, the tail is not mechanically connected to the stick and inputs are transmitted “over a wire,” but that’s like confusing the F-14’s boost mode for TF30 engine control with FADEC (throttle lever position transmitted “over a wire” to the engine).

Wanna know something that is FBW on the F-14? The roll spoilers. Because they can be commanded to max or min position by computer without pilot input when appropriate (ground braking, inhibiting when wings are swept) as well as summing inputs when appropriate (DLC mixed with roll input).

Yes, Fly-By-Wire literally means input is sent over wires but there are other requirements, too. Like having a digital computer with full authority over control surfaces rather than analog systems with only limited authority to modify the position commanded by the stick. Electronic not electric, computer drives the plane, rather than making reactive adjustments to pilot input.
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32 minutes ago, r4y30n said:

Sure, the tail is not mechanically connected to the stick and inputs are transmitted “over a wire,” but that’s like confusing the F-14’s boost mode for TF30 engine control with FADEC (throttle lever position transmitted “over a wire” to the engine).

Fly by Wire technology has gone a long ways from using potentiometers and using a direct, analogue signal to actuate servos (e.g. in the lower stage of the Mistel flying bomb in cruise) to incorporating digital computers that have full autority. That doesn't make the original or the incremental technology stop being FBW.

1 hour ago, r4y30n said:

Wanna know something that is FBW on the F-14? The roll spoilers. Because they can be commanded to max or min position by computer without pilot input when appropriate (ground braking, inhibiting when wings are swept) as well as summing inputs when appropriate (DLC mixed with roll input).

The GND-spoiler mode selector switch is literally selcted by the pilot. The scheduling of spoiler inhibit commands isn't really fancy, as it's just a function of sweep-angle (57° stops spoiler commands, 62° mechanically locks the spoilers).

The only semi-exciting thing the CADC and it's associates do is changing the spoiler commands with flap-setting and DLC position. Most of which is probably open loop, but the manuals I have don't did deep enough.

1 hour ago, r4y30n said:

Yes, Fly-By-Wire literally means input is sent over wires but there are other requirements, too. Like having a digital computer with full authority over control surfaces rather than analog systems with only limited authority to modify the position commanded by the stick. Electronic not electric, computer drives the plane, rather than making reactive adjustments to pilot input.

That's why it was called "Digital Fly by Wire" back in the day. It's just an incremental and logical step forward.

By your logic, Concorde, lacking the "digital full autority" FCC, isn't FBW. Don't tell that to the Brits or the French.

When an AFCS box instead of a FCC box drives the plane, how is that then not FBW to you? With AFCS in "Stab Aug", the pilot has no authority over the dampening system-inputs other than switching the system off altogether*. The pilot has even less control if the AFCS is in Auto Pilot, where he can only dial in the desired parameters.

This is where your interpretation of what FBW is and what it's not, is unnecessarily narrow and complicated. At the end of the day we're splitting hairs here.

____

* Sully hit the Hudson hard in Direct Law (direct relation between stick-deflection and flight control surface deflection), because he forgot about the phugoid dampening function which for all intents and purposes is just a fancy Stab Aug system - who's got full authority there? Yes I know there's several different digital boxes between the sidestick and the elevator in an A320, but that's not the point here.

So ein Feuerball, JUNGE!

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On 12/5/2021 at 8:13 AM, Mr_sukebe said:

Interesting how the F14 is apparently considered as 4th gen.  I always previously considered the “peak” of 3rd generation design, as it has no fly by wire.

I have the same opinion except not specifically because of the lack of FBW. IMO Looking at the F-14 there was nothing really revolutionary about it so much as it represented the apex of existing technology. Nothing really new came about until the F-16 with its exclusive FBW controls.

But that is probably a tangent best left for a different thread. No point in high jacking this one.


Edited by Cab
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The new thing in the F-16 wasn't the electric controls, but the relaxed pitch stability, enabling better performance. It's also the reason why it doesn't have a mechanical backup. It's just not controllable.

The A-5 Vigilante was the first american production aircraft with FBW controls (with mechanical backup). It also Intruduced the HUD, which was then called "Pilot's Projected Display Indicator" (PPDI). The first production aircraft with FBW altogether was most probably the Avro Vulcan, also with mechanical backups.

Careful with the "exclusive FBW" argument - that way, you'd throw airplanes like the Tornado or the F/A-18A-D (mechanical backups) over board.

 

Now let's go back to the F1.

So ein Feuerball, JUNGE!

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