DCS: AJS-37 Viggen Discussion

[robban75]

Working on it. :D He's still a bit too young I think. I got hooked by F/A-18 Interceptor back in the 80's, and I was probably around 12-13 years old when I got into it, almost twice the age of my son. We'll see. He loves Top Gun and the F-14. So, things are going in the right direction. ;)

[Buzzles]

(it's quite easy; even small children in Sweden understand it)

:lol:

[BravoYankee4]

I'm actually kind of retarded because I forgot I actually have that picture in English translation (from the unclassified part of the JA 37C English flight manual). The JA 37 isn't exactly the same (note for example four elevon servos per side instead of three) but it's close.

 

 

One of these days I'll get the PDF finished, I promise...

 

This one makes me a little puzzled: "Pedalkraftsgivare" is translated to "Pedal force generator".

"Givare" in Swedish would better be translated to sensor, not generator. So is it a bad translation, or am I reading the Swedish term in the wrong context?

[Sporg]

This one makes me a little puzzled: "Pedalkraftsgivare" is translated to "Pedal force generator".

"Givare" in Swedish would better be translated to sensor, not generator. So is it a bad translation, or am I reading the Swedish term in the wrong context?

I think you are right, in this case it is a bad translation.

It should be Pedal force sensor.

 

Same with "Stick force generator", it should be Stick force sensor.

 

Edit: As discussed later in the thread, the "force generator" translation in the document is apparently correct.

Edited October 25, 2016 by Sporg
Correction

[MiG21bisFishbedL]

Just make sure you try him out on Flight sims while he is young to get him in deep.

 

My father stuck me with Janes F-15 and Microsoft Combat Flight Simulator 1 when i was 5.

 

And look at me today... a complete Flight Sim / Aviation Geek.

 

I ended up actually flying for a living. :pilotfly:

[Goblin]

I ended up actually flying for a living. :pilotfly:

 

Loser!

So did I... ;)

[Helikopter]

Started my flight sim carrer when I was about 8 years ord. Ended up as a helicopter pilot :-P

 

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[renhanxue]

This one makes me a little puzzled: "Pedalkraftsgivare" is translated to "Pedal force generator".

"Givare" in Swedish would better be translated to sensor, not generator. So is it a bad translation, or am I reading the Swedish term in the wrong context?

I agree with Sporg, I think the translator messed it up. I've seen some pretty obvious mistranslations in this just from glancing at it, for example the term "normalplan" (as in, the plane of the geometric normal - the vector perpendicular to a plane) got translated as "standard plane" which makes no sense at all.

[microvax]

I guess Pedalkraftgeber would be similar. Theese non Viking english speaking people didnt get the memo that a Geber => giver ist a sensor not a generator. :D

 

At least thats what my intense guessing at swedish yields in this case ! :D

[outbaxx]

I think that it's correct with generator, it generates a force to the stick when you pull it, the force increase as you pull.

[Goblin]

Yes, the flightcontrols had artificial force feedback. There are no force sensors.

[renhanxue]

I think that it's correct with generator, it generates a force to the stick when you pull it, the force increase as you pull.

Pedals, not stick. But you're right, I went back and checked and "givare" is used in an unusual way here, the device in question is an artificial pedal force generator.

 

Yes, the flightcontrols had artificial force feedback. There are no force sensors.

Right and wrong. The artificial stick and pedal forces are a thing, yes, but there are force sensors on the stick even though the flight controls are mainly hydro-mechanical and not electronically governed. If you take a look at the English diagram again there's a "stick force sensor" right there, and that is correctly translated. It's used by the autopilot for various things like oscillation dampening, transonic trim, etc.

[Sporg]

I think that it's correct with generator, it generates a force to the stick when you pull it, the force increase as you pull.

Pedals, not stick. But you're right, I went back and checked and "givare" is used in an unusual way here, the device in question is an artificial pedal force generator.

Yes, the flightcontrols had artificial force feedback. There are no force sensors.

Right and wrong. The artificial stick and pedal forces are a thing, yes, but there are force sensors on the stick even though the flight controls are mainly hydro-mechanical and not electronically governed. If you take a look at the English diagram again there's a "stick force sensor" right there, and that is correctly translated. It's used by the autopilot for various things like oscillation dampening, transonic trim, etc.

Ok, interesting.

 

I'm sorry I got it wrong, the Swedish document apparently uses two kinds of "givare", one as a sensor and the second as a force generator.

 

So there's stick and pedal force generators, and different position and roll link sensors.

Edited October 25, 2016 by Sporg

[Goblin]

If you take a look at the English diagram again there's a "stick force sensor" right there

 

Where? Do you mean the stick position sensor?

[renhanxue]

Where? Do you mean the stick position sensor?

Right, sorry, stick position sensor. It's extra confusing because it's "spaklägesgivare" in the Swedish version - "givare" is used in the other sense there.

[Goblin]

Right, sorry, stick position sensor. It's extra confusing because it's "spaklägesgivare" in the Swedish version - "givare" is used in the other sense there.

 

Yes, and this is not a force sensor. It feeds the position of the stick into the artificial feel unit, which outputs a feedback force based on the stick position (and speed, altitude, etc.)

[renhanxue]

Yes, and this is not a force sensor. It feeds the position of the stick into the artificial feel unit, which outputs a feedback force based on the stick position (and speed, altitude, etc.)

How far do you want to take that particular semantics argument? My understanding is that there are stick position and force sensors (but no pedal force sensors, so I was wrong on the original point anyway). Depending on your definition of force sensor, I guess.

 

 

Still the original point of the argument stands; "givare" is used both for a pure sensor and for a device that can both generate stick forces (but perhaps it makes more sense if it can also report back the current force, something that I am not entirely clear on).

[Goblin]

How far do you want to take that particular semantics argument?

 

"Nothing further, you honour!" ;)

 

My understanding is that there are stick position and force sensors (but no pedal force sensors, so I was wrong on the original point anyway). Depending on your definition of force sensor, I guess.

 

Well, yes, I guess you could view the flight control inputs (stick and rudder) as a force sensing unit, since it translates the force, applied by the pilot, into flight control deflection.

 

But I just meant that the translation was correct, and that there were no force sensors in the schematics. :). I just wanted to explain myself. Nothing sinister. ;)

[renhanxue]

Oh, no, sorry if I came off as hostile or something. I just want to understand what is going on here :)

It sometimes does get into the territory of insufferable pedantry, and I should be more aware of that.

Edited October 25, 2016 by renhanxue

[Sporg]

A description of the "Spakkraftsgivare" is found in the AJS-37 Pilot's Manual, Chapter 12, section 3.1.5:

 

 

Basically it says, that since the control surface servos provide all the necessary power to move the control surfaces,

the "spakkraftsgivare" (stick force generator) works to give the pilot feedback on the stick in the form of force (resistance to movement)

proportional to the stick deflection from neutral. It is basically a mechanical cam with springs.

 

In addition there is a trim attenuator that can move the location of the neutral point of the stick.

 

Normally these forces will be 12 N in pitch and 7 N in roll.

 

If the pilot has selected autopilot attitude or altitude hold, the breakout forces are amplified by a magnetic coil to 30 N and 23 N respectively.

 

The pedal force generator works along the same principles except the hold function.

Edited October 25, 2016 by Sporg

[Goblin]

Oh, no, sorry if I came off as hostile or something.

 

Yeah, you scared me..! ;) No, seriously, I was afraid that I came across as hostile. :)

 

It sometimes does get into the territory of insufferable pendantry, and I should be more aware of that.

 

Attention to detail can never be negative! ;)

[outbaxx]

A description of the "Spakkraftsgivare" is found in the AJS-37 Pilot's Manual, Chapter 12, section 3.1.5:

 

Normally these forces will be 12 N in pitch and 7 N in roll.

 

If the pilot has selected autopilot attitude or altitude hold, the breakout forces are amplified by a magnetic coil to 30 N and 23 N respectively.

 

 

 

These forces are the "break out" force that you need to apply to move the stick. The force then increase as you pull further to about 150-170 N at max in pitch depending on what mode is selected.

[Sim Flyer]

I might be an optimist here (and a bit naiv for getting the information from wikipedia) but first of all, someone in here asked if the RBS15 could be used for land targets and the answer was only the new one that was designed to be operated on ships (as stated below).

 

RBS-15 Mk. IIIRange over 200 km, with land attack capability.[2] New warhead (increased penetration and insensitive munitions qualification) from TDW. There is only a ship launched version. Production started in 2004. New oval launch tubes instead of the old box type.[3]

But then i saw the next line and started wondering if this missile was ever used on the Viggen or if it was only used on Gripen.

 

RBS-15F ERAircraft launched version of the Mk. III

Anyone knows anything about this?

[Airbusdriver]

Hi! Been following your discussions a bit. See a bit of confusion about spakkrafts givare, spaklägesgivare, spakkraftstyrning.

In my belief and knowledge about aircraft systems I understand the manual and pictures as follows to help those out that doesn't have swedish as their first language.

Spakkrafts givare= Artificial feel unit. Create natural stick forces for the pilot since a full servo system has no feelback to make manuvering natural.

Spaklägesgivare=Stick position sensor to feed signals to the artificial feel unit about current control input.

Spakkraftsstyrning= A system separate from the previosly two. Electrical force sensors located right beneth the top handle portion of the control stick. Theese signals are transmitted to and added to the autopilot/dampening signals in SPAK mode and transmitted to the outer elevons.

This system creates a very fine and precise manuvering.

Look at a videos were su27s do formation flying and you'll see pilots working the stick like maniacs without any significant path change. In the viggen this system lets you keep e stick almost still as it senses and reacts to your inputs immediatly and comes very natural for the pilot.

Very clever system. Rememer when I helped out dismateling old AJ Viggens, when the top of the stick is removed you can see the electrical pressure sensors located as 12 little dots in a round circle.

I beleve this system was made inoperative on the JA version as they fixed the inner and outer elevons together and instead used a more sofisticaded autopilot/dampner but i'm not sure and I have not seen any documantation describing it in detail.

Anyone that know were I can find the SFI for the JA version?

/

Anders

[RaXha]

I might be an optimist here (and a bit naiv for getting the information from wikipedia) but first of all, someone in here asked if the RBS15 could be used for land targets and the answer was only the new one that was designed to be operated on ships (as stated below).

 

RBS-15 Mk. IIIRange over 200 km, with land attack capability.[2] New warhead (increased penetration and insensitive munitions qualification) from TDW. There is only a ship launched version. Production started in 2004. New oval launch tubes instead of the old box type.[3]

But then i saw the next line and started wondering if this missile was ever used on the Viggen or if it was only used on Gripen.

 

RBS-15F ERAircraft launched version of the Mk. III

Anyone knows anything about this?

 

 

 

The AJS 37 only carried the MkII as far as I know, so it won't be ground target capable. :-)

 

 

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