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Viggen range


Birko

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Does anyone have, or know where to look for, data on what sort of mach number or IAS and altitude gets you the longest range out of the Viggen?

 

I'm guilty of running the tanks dry on too many occasions now :doh:


Edited by Birko
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At low level it is Mach 0.55, for other altitudes you can consult the table on page 173 of the manual. Range is 1700 km or 2100 km depending on the presence of an external fuel tank. This probably holds for a higher altitude though. Also, I never ever get this far ...

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Thank you for bringing up the manual! I haven't thoroughly read through it since I first bought the Viggen and had completely overlooked the chart with the economic air speeds.

 

I wonder if the mach numbers it gives at the different altitudes are all roughly the same true speed, I'll try and figure out which altitude/mach mix gives the longest range, at least on paper.

 

Also, I never ever get this far ...

 

That's a sentiment I can relate to all too much.

 

Thanks!

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Using an online calculator (temperatures and pressures can vary, so with both of these points in mind this is very much to be taken with a pinch of salt) I got the true speeds of the 'economical' mach numbers at the altitudes the chart on page 173 gives.

 

0m mach 0.55≈675kph

3000m mach 0.66≈780kph

6000m mach 0.76≈865kph

9000m mach 0.87≈950kph

10000m mach 0.9≈970kph

 

The general consensus seems to be the higher, the better. I know the engine doesn't die until something like 15000m so it'd be great to have data going up to these altitudes too, although if higher altitudes aren't covered in the manual, it's safe to assume those altitudes aren't economical?

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The general consensus seems to be the higher, the better. I know the engine doesn't die until something like 15000m so it'd be great to have data going up to these altitudes too, although if higher altitudes aren't covered in the manual, it's safe to assume those altitudes aren't economical?

 

The higher you go the more economical you will be in any aircraft - which is why civilian airliners hang out at 30k feet to cruise. It boils down to friction for the most part.

 

The Viggen's control surfaces don't like supersonic speeds - though the aircraft on the whole performs marvelously up there. I am by no means a physicist, but I imagine that a greater deal of energy is needed to further propel you past the sound barrier, so if economic speed for M0.9 is at 10k meters - ideally above that M0.9 would then psudo-logically still make sense as the most efficient. I know once you pass the barrier dynamics change in ways I can't currently imagine, but that is my quazi-Newtonian theory on the 10k ceiling presented in the manual. :joystick:

---

AJS37 Viggen, F-16C Viper, Adobe Premier.

X56 HOTAS, Ryzen 7, GTX 2070S

youtube.com/leadnapgaming

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Great input, thanks!

 

Also can't say I'm a physicist, but I think at transonic speeds a shockwave builds that increases drag, probably?

 

I agree with you about the economic mach never exceeding about 0.9 because of transonic effects (at least not before the Viggen's ceiling) so you'd have to go slower (in true speed) at higher altitudes to keep subsonic thus reducing your range.

 

I'll leave this here for other Vig pilots to read and hopefully keep their tanks from drying up, or for someone to correct me on :pilotfly:

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If no one has mentioned it, are you aware that the second dial (the striped one) on the fuel gauge shows how much fuel you need to fly the rest of the route? It shows fuel needed at current fuel consumption regarding speed and height (up to IIRC M0.8) for the current leg and from next waypoint at planned speed and sea level altitude. There’s also additional margin for the landing approach (via LB) and reroute to L2 from L1 + a set margin that you can change in TAKT (10% default IIRC). So if you see that your fuel dial is at or below the striped one you need to turn off the afterburner. If it’s significantly below you should abort and fly straight home as economically as possible (high altitude and ~500km/h).

DCS AJS37 HACKERMAN

 

There will always be bugs. If everything is a priority nothing is.

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Ah, the little fuel gauge tie? I've always managed to run a bit below that, it doesn't account for the many kilometres I usually end up gliding back to base with all the (beautiful, by the way) something's gone wrong lights blaring at me.

 

Is the M0.8) supposed to say M0.8? :P

 

So if I understand correctly, the fuel needed calculation is based on:

•Current consumption -up to mach 0.8- for current leg

•Consumption at planned speeds and assuming sea level for other waypoints

•Extra margin for landing approach, and reroute to L2 if there's an L2

•Extra 10% if you want (and I probably do at this rate)

 

Thanks for the help, it's a learning curve as with all modules and great work on the Viggen I'm loving it!

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Ah, the little fuel gauge tie? I've always managed to run a bit below that, it doesn't account for the many kilometres I usually end up gliding back to base with all the (beautiful, by the way) something's gone wrong lights blaring at me.

 

Is the M0.8) supposed to say M0.8? :P

 

So if I understand correctly, the fuel needed calculation is based on:

•Current consumption -up to mach 0.8- for current leg

•Consumption at planned speeds and assuming sea level for other waypoints

•Extra margin for landing approach, and reroute to L2 if there's an L2

•Extra 10% if you want (and I probably do at this rate)

 

Thanks for the help, it's a learning curve as with all modules and great work on the Viggen I'm loving it!

 

I am still impressed by the fact you are airborne long enough for it to be a problem! I only say that because in general I don't run into fuel constraints in the Viggen like I do other aircraft, though I've only made one mission where if you don't fly economically a glide will definitely be the landing used... I average about 35-45 minutes in the air per "flight", and stick to low level flights which should burn more fuel :joystick:

---

AJS37 Viggen, F-16C Viper, Adobe Premier.

X56 HOTAS, Ryzen 7, GTX 2070S

youtube.com/leadnapgaming

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I am still impressed by the fact you are airborne long enough for it to be a problem! I only say that because in general I don't run into fuel constraints in the Viggen like I do other aircraft, though I've only made one mission where if you don't fly economically a glide will definitely be the landing used... I average about 35-45 minutes in the air per "flight", and stick to low level flights which should burn more fuel :joystick:

 

Zone 3, is all I can say to explain myself.

 

I usually last maybe 20 minutes, for example, in the 'offensive counter air' instant action mission, although that could be longer and I just use time compression a bit too much. And that's with an external tank, but I think A/A combat is the worst thing for range and fuel consumption.

 

Flying at a good mach at a good alt helps, but I tend to fly M1.7 pretty much there and back which in retrospect can't help :joystick:

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Zone 3, is all I can say to explain myself.

Flying at a good mach at a good alt helps, but I tend to fly M1.7 pretty much there and back which in retrospect can't help :joystick:

 

Ahhh … yea I stick to military power, fly under 100m, and burn on ingress and egress.

---

AJS37 Viggen, F-16C Viper, Adobe Premier.

X56 HOTAS, Ryzen 7, GTX 2070S

youtube.com/leadnapgaming

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