Viggen on carriers? Feasible or not?

Interview of Viggen pilot.

http://www.milavia.net/specials/iv_viggen/index.htm

Wrong.

Notice the 3 big smilie faces? Please learn sarcasam… :rolleyes:

If a C-130 can take off and land on the deck of an Aircraft carrier, then im sure that pretty much any fighter aircraft can too

Wrong.

If a C-130 can take off and land on the deck of an Aircraft carrier, then im sure that pretty much any fighter aircraft can too 😀 😀 😀 (video for those who have never seen it: http://www.youtube.com/watch?v=BjNyQvhsQE8 )

About it being a reasonable thing to do though…. it seems a bit pointless to me :shrug:

Back to the original topic,

I agree, no 21st Century FBW system and landing aids to help out like on the Rafale.
In regards to the topic, what do you make out of this?
“The canard doesn’t contribute much lift in itself during normal flight, it acts more as a gigantic vortex generator for the main wing. During low speed flight, its rear edge flap can be lowered to increase lift and permit a high nose angle.”
(http://www.canit.se/~griffon/aviation/text/37viggen.htm)

I have taken a look at your linked file. First, nice that you linked it. It is definitely result of some serious research. However, the author uses some methods which are doubtful in reliability for prediction of low speed characteristics for a quite non-linear airframe. Still, the guy assumingly knew that and tuned his inputs by orienting on the stated performance results. I have to take a deeper look at the file and will later come back.

Back to the original topic,

I think the approach speed is in line with other carrier aircraft, only the pitch attitude is a problem. That might be the biggest problem of the Viggen, as its delta doesn’t really produce much useful lift at low angles of attack (while the canards do help).

I agree, no 21st Century FBW system and landing aids to help out like on the Rafale.
In regards to the topic, what do you make out of this?
“The canard doesn’t contribute much lift in itself during normal flight, it acts more as a gigantic vortex generator for the main wing. During low speed flight, its rear edge flap can be lowered to increase lift and permit a high nose angle.”
(http://www.canit.se/~griffon/aviation/text/37viggen.htm)

I use the stated ferry range since there is no standard configuration for maximum range. Even designations such as “Hi-Lo-Lo-Hi” does not tie down enough parameters to really evaluate the effective combat range of a fighter bomber.
—
It is not just landing speed but also many other factors such as
AoA, not stated in numbers like this are factors such as minimum wind over the deck, etc.

Yes, that’s what I’ve been saying. The whole point of my post you quoted was to point out the potential inaccuracy and incompleteness of internet sources. So it seems we’re in agreement here.

And that’s also why I mentioned the Mirage 2000 and the F-16. Because you have some public combat range figures on the Mirage which are based on the loadout with three tanks and 6 AAM, you get a good number. Obviously if the USAF wanted to commonly load a F-16 with three large drop tanks in stead of the two underwing we commonly see, they could – but the reality is that a F-16 combat range would be stated with a standard two-tank loadout, which does not reflect accurately on the airplane but does reflect on practices by the user air forces.

See my point about comparing A-4 and Saab 37 ferry range? Ferry ranges I’ve seen have always been given with full internal fuel plus however many drop tanks you can stick on the plane, or unspecified on that point. The Viggen was only used for intercept/top cover missions over the Baltic and they only had to ferry the airplanes within Sweden, because of that they used a single tank and because of that you’re of course not going to get a range figure comparable to a Mirage with 4500 litres of external fuel.

As for the A-4, I think it was introduced in this thread in relation to a hypothetical 1970’s era non-US carrier?
I do really like the subsonic strikers and think they have great character, Skyhawks, Buccaneers, Intruders, and obviously the USMC held on to the A-4 for so long for a good reason. (Just like they have a good reason for keeping the Cobra and requiring the AV-8 and F-35B development etc.)

However with a limited amount of hypothetical carrier deck in 1970, I think I would choose a hypothetical navalized Viggen for the same reason the USN introduced the Hornet in the 1980’s. Both airframes are built for air-to-air combat (in one fashion or another, one being an interceptor and the other a dogfighter) and are considerably heavier afterburning designs with room for a larger radar.
Yes a light attack fighter will benefit in its primary mission from not needing the afterburner or a large radar, and I do think efficient designs like the Intruder, Viking and Corsair would not be out of place on a year 2007 Nimitz class deck.
But having said that, the USN did begin to eliminate specialist ground attackers in the mid-80’s and I think that with a smaller carrier you more reason to do so. Just MHO.

RE: Viggen on carriers? Feasible or not?

Adrian,
in what circumstances? Internal fuel or with external tanks?

The range figures are based upon the normal configuration to ferry an aircraft from one place to another, good advertisement type stuff.

you haven’t actually answered the question.

Is this the question you are referring to, “Could you tell me how you work out that the A-4 could carry more weapons & have a greater range than the Viggen?” If it is the question, the Skyhawk is just an older but more capable design as an attack aircraft!!

What are your sources? And you haven’t actually answered the question.

US Navy and Douglas Aircraft Corporation. They both boasted the A-4 was the first aircraft to be able to carry a heavier weapon’s load than the weight of the plane itself.
This was current events long before the ARVNET!
When you look at the data from the URL provided by Badger 1968, you will recognize that the A-4 was a fine airplane whos design was ahead of its time!

I think the weapons load question is a case of the usual US practice always having been to quote the maximum theoretical external load (all pylons fully loaded)

This is a common practice in US aerial combat operations (PGW#1, Kosovo, PGW#2, etc). To take off with a maximum ordnance load, minimum fuel load and, proceed to an aerial tanker to fill up the fuel tanks. Bingo fuel is calculated upon getting back to the aerial tanker.

About the 1250 mile ferry range

I use the stated ferry range since there is no standard configuration for maximum range. Even designations such as “Hi-Lo-Lo-Hi” does not tie down enough parameters to really evaluate the effective combat range of a fighter bomber. There is nothing spelled out how far the “lo” is, no standard load of weapon or fuel, not to mention the effects of winds aloft, etc. Ferry range is a measurement of how far a plane can go with the fuel it takes off with, that is all.
The most meaningful comparisons tend to come when you can visit one URL and get the information on several aircraft being compared.

I’m not sure how to interpret the landing speeds in relation to what we know of planes like the Rafale.

It is not just landing speed but also many other factors such as
AoA, not stated in numbers like this are factors such as minimum wind over the deck, etc.

Thanx, Bager1968 for your reference URL.

Adrian

I’m not sure how to interpret the landing speeds in relation to what we know of planes like the Rafale. Which of the three speeds given here coincides with the the 115kt commonly given as Rafale approach speed? I’ve also seen 250km/h (134kt) given for Etendard IVM approach.

That the first speed is only given in km/h while the rest are in kt, km/h form… seems to suggest that the 220km/h (119kt) number is taken from a different source than the two others, with the implications that fact brings.

I think the approach speed is in line with other carrier aircraft, only the pitch attitude is a problem. That might be the biggest problem of the Viggen, as its delta doesn’t really produce much useful lift at low angles of attack (while the canards do help).

…The range and warload numbers given in some cases can be more a function of operational practices with different air forces than whatever the plane is capable of….

Yes, I’m sure that is the case. Unfortunately, it’s often hard to extract comparable figures from the plethora of numbers quoted.

On to the original topic;
This document compiles lots of various info on the plane. Unfortunately the somewhat inadequate manner of referencing lists 20 different sources, from Jane’s to Key Publishing, but does not say which bit of info comes from exactly what source. So these numbers will of course have to be taken with a pinch of salt.

Of interest is this:

8. Landing
Landing Run approx 500 m
Landing Speed 220 kmh
The undercarriage is lowered.
The thrust reverser is pre-selected to activate immediately after landing.
The approach is steep.
The aircraft attitude is 15 degrees nose up.
The speed is controlled by the autopilot.
The aircraft crosses the runway threshold at 130 knots (240 kmh).
Touchdown with a no-flare landing at 97 knots (180 kmh).
Touchdown is about 45 metres (150 feet) beyond the runway threshold.
The undercarriage is designed for a landing sink rate of 16 feet/sec (5 m/s).

I’m not sure how to interpret the landing speeds in relation to what we know of planes like the Rafale. Which of the three speeds given here coincides with the the 115kt commonly given as Rafale approach speed? I’ve also seen 250km/h (134kt) given for Etendard IVM approach.

That the first speed is only given in km/h while the rest are in kt, km/h form… seems to suggest that the 220km/h (119kt) number is taken from a different source than the two others, with the implications that fact brings.

About the 1250 mile ferry range, that’s actually the combat range. According to my mag the JA 37 has a 1000km combat radius with 6 AAM + centreline tank (have seen 1400l and 1275l given for those tanks) on a hi-lo-hi mission.

Same as with the warload numbers issue, because tanks weren’t normally carried anywhere else than on the centreline, it can be used as ferry range for lack of any other number.
It’s like the Mirage 2000 having a longer nominal range than the F-16 because they use warloads with 6 AAM and three big tanks (2x2000l and 1×1500? See this pic.). The range and warload numbers given in some cases can be more a function of operational practices with different air forces than whatever the plane is capable of.

In the event that SAAB would have had to fly planes down to India or Australia, obviously we would have seen tanks under the wings and probably a Mirage-style IFR probe. (They have a history of modifying for customer needs, the Danish F-35 Draken had 35% more internal fuel, a larger wing and three more pylons along with structural strengthening for Bullpup/dumb bomb carriage. The JAS 39C with the retractable IFR probe, strengthening for KEPD 350, NATO’s datalink in addition to TILDS, etc.

Also you have the F-4K and F-8E(FN) as examples of pretty extensive customization that took place “back in those days” seemingly without spending much time on it. UK gov approved F-4K in June 1964, YF-4K flew in July 1966. French saw the F-8 at the Paris air show in 1962, first production model F-8E(FN) flew in June 1964.)

Vectorsite.net. I do know that Swedish source, I mentioned the site when talking about the Olympus having the RM7 designation earlier. I choose to disregard it as he gives the same empty weight for the AJ and JA even though texts on development states there was a weight increase. Oh and check PMs, I sent a clarifying one before I saw that last post….

Ah – just saw this. Yes, that doesn’t fit. BTW, I’ve also seen a figure of 400 kg for the JA37 weight increase over the AJ37. I’d like to have definitive answers to this, now my attention has been drawn to the discrepancies. Hmm. I wonder where to look?

BTW, I think the weapons load question is a case of the usual US practice always having been to quote the maximum theoretical external load (all pylons fully loaded), even if that means light on fuel, whereas the practice elsewhere has often been to quote the maximum actual load. In the case of the AJ37, I think the centreline pylon was always used for the fuel tank I mentioned before, which the Swedes never counted towards the weapons load (it’s not a weapon!), & the heaviest store used was the Rb04 missile, which weighed 600kg, but the hardpoints (except the two outermost, which I think might have been missile only – and not usually used because of vibration problems) could take more, hence the oft-quoted 6000kg maximum load. A Buccaneer/A-6 comparison runs into the same problem: the Bucc never actually carried more than 12000lb of weapons, despite a theoretical capacity of 16000lb, so 12000lb used to be quoted as its maximum.

I think the Viggens internal fuel capacity was about 6000 litres.

Yes, the A-4 Skyhawk made aviation history by being the first fighter-bomber that could take-off with an ordanance load great than the weight of the bare aircraft! The ferry range of the A-4 is over 1,700 miles while the Viggen is 1,250 miles.

Adrian

Adrian,

in what circumstances? Internal fuel or with external tanks? What are your sources? And you haven’t actually answered the question.

Final solution (that sounds rather nazi like doesn’t it, sorry)… Look at the Gripen site for the official specs!

Gripen Technical Summary please note that it states a RM-12 engine and a MTOW of 14 tonnes.

As for the Viggen: Jane’s have it listed as:
AJ-37: RM-8B rated at 72.06kN Dry (no comment on Burner)

MTOW: 45,194 lb (20500 kg) — for attack

Has 4x underwing hard points and 3x underfuselage hard points for carriage of weapons to suite model (center line and inboard wing pylons are wet and fully plumbed for fuel, the SH-37 and SF (Later designated AJSF) models usually carried two wing mounted fuel tanks or one centerlined tank depending on the mission, they are also noted as still retaining the ability to carry MOST of the standard weapons load outs of the Viggen series which was standard doctrine in the Swedish Air Force (Svenska Flygvapen).

A-4M (heaviest of the skyhawks)

1x Pratt & Whitney J52-P-408 11,200lb (50kN) thrust

Normal Take off Weight: 24,500lbs (11,115kgs)

As stated, it was a great light strike fighter, but the Viggen is made for heavy duty work.

http://home.att.net/~jbaugher4/newa4.html

A-4A: Weights: 8391 pounds empty, 15,093 pounds combat weight, 19,910 pounds maximum. Armament: Two 20-mm cannon with 100 rpg. plus up to 5000 pounds of ordnance on 2 underwing pylons and one centerline pylon.

A-4/B/C: Weights: 9146 pounds empty, 15,359 pounds combat weight 17,535 pounds gross, 22,500 pounds maximum. Armament: Two 20-mm cannon with 100 rpg. plus up to 5,000 lb of ordnance on 2 underwing pylons and one centerline pylon.

These all used the J65-W-16 (7,700 lb.s.t.) or J65-W-20 (8,400 lb.s.t.) [US-built Armstrong-Siddeley Sapphire 100]

A-4E/F: Armament: Two 20-mm cannon with 100 rpg. Maximum weapons load 8200 pounds on four underwing pylons and one centerline pylon.
Weights: 9,624 pounds empty, 18,300 pounds gross, 22,950 pounds maximum.

A-4M: Armament: Two 20-mm cannon with 100 rpg. Maximum weapons load 8200 pounds on four underwing pylons and one centerline pylon.
Weights: 10,418 pounds empty, 18,500 pounds gross, 24,500 pounds maximum*.

Fuel for both is 900 gallons internal and up to 3 x 300 gallon drop tanks.

* from “Ships & Aircraft of the US Fleet 12th ed. (1981)’, as JBaugher lists the same MTOW for both versions.

From other sources I have seen that that is the max carrier-based weapons load, and that the max land-based weapons load for the A-4M was 9,900 lb, due to its higher-power engine.

The A-4M had the 11,200 lb.s.t. J52-P-408 vs the 9,300 lb.s.t. J52-P-8 of the A-4E/F (early A-4Es had the 8,500 lb.s.t. J52-P-6A initially, but this was replaced with the -8).

RE: Viggen on carriers? Feasible or not?

Could you tell me how you work out that the A-4 could carry more weapons & have a greater range than the Viggen?

Yes, the A-4 Skyhawk made aviation history by being the first fighter-bomber that could take-off with an ordanance load great than the weight of the bare aircraft! The ferry range of the A-4 is over 1,700 miles while the Viggen is 1,250 miles.

Adrian

I think most Mirage exports were to countries where Draken wasn’t on offer, because of Swedish export restrictions, but there were a few where it could have been sold, e.g. Australia. The biggest lost opportunity was the big German purchase of F-104s. Imagine the Luftwaffe replacing its Drakens with Viggens, instead of buying F-104s then F-4s . . . . .

The Olympus engine was considered for the Viggen, but dropped. A pity.

Great topic (Reading once again). Just for the last part of your post (I hope to answer to the original question later if I can justify it): Draken and Viggen would have been viable solutions for the Luftwaffe, but focus was on delivery of nuclear weapons and the Starfighter was OK for that. Still, both aircraft would have performed equally well in the arsenal.

Vectorsite.net. I do know that Swedish source, I mentioned the site when talking about the Olympus having the RM7 designation earlier. I choose to disregard it as he gives the same empty weight for the AJ and JA even though texts on development states there was a weight increase. Oh and check PMs, I sent a clarifying one before I saw that last post.

Funnily enough, F7.mil.se does indeed give the 37 empty weight as 9.5t. It also gives the Gripen MTOW as 12.5t and the RM12 80.0kn thrust. Now go to F17.mil.se and you will find Gripen MTOW at 14t and the RM12 at 81kn. Conclusion: an uninterested conscript was assigned to data entry when mil.se redesigned their website…?

Edit: Just dug up this rag:

AJ 37 article: empty weight given as ca “20t”, assuming that’s a typo and that they meant ca 10t. Max external load given as 4000+ kg. The article also gives a combat radius number with six Mk82 even though nothing like a Mk82 was in the inventory, so it’s a bit off in facts.

JA 37 article: empty weight given as 12.2t, max external load 6000kg. This article claims the weight increase is 1t up from the AJ.

(Miscellaneous info from the mag: 700mm radar antenna diameter.
Engine change: 4 hrs, radio system change: 5 mins, wheel change: 6 mins.
And US defence secretary at the time, Kaspar Weinberger, is said to later have regretted blocking the potential sale to India.)

Seeing as it weighs over three times as much as an A-4A, …

Swedish sources quoting SAAB & the Swedish air force say the Viggen empty weight was 9500 kg. Or do you prefer Wikipedia in English?