F-15C Rudder Action?

[Rex]

Due to the carrier, and full-fidelty of the plane, I am primarily an F/A-18 DCS driver these days, although the F15 has been my favorite plane for most of my life. and I'm looking forward to the full-fidelity Strike Eagle. 

 

I do hop in the FC3 version from time to time, and when I do, I'm always left with a question:

 

Is the rudder modeled correctly? On a gutcheck level, it feels like it's a bug, or just hasn't been modeled completely, but what do I know, maybe it's spot on.

 

I have Thrustmaster Pendulum Pedals (yes, I spent $500 on pedals, that's what happens when I open the tax refund check first), which means I use the pedals pretty often while flying to avoid having spent $500 simply to taxi.  I know most fighter pilots don't use the rudder that often, but then again, they didn't pay for the pedals themselves, or they might.  I'm using the default 45 degree curve linear calibration.  At full-ish speed, Mach 2.2 or so, I can get full deflection on the rudder.  The degree to which the nose yaws at high speeds is incredible, and it far exceeds the F18, which barely yaws at high speeds even with full pedal.

 

I'll be blasting through the air in full burner, rocking the pedals back and forth and effortlessly wagging the nose like a dog's tail.  It seems to move the same at high speed as it does low speed.

 

Is this real or is it unintentional.  I've actually ripped the 15 apart before by sustaining high G's, but the rudders at full deflection produce no damage at all.

 

Does anyone have any insight into this?  In general, how do you find the yaw control to be in the plane?

 

Edited February 8, 2021 by Rex
minor addition

[Spurts]

Keep in mind the designs of the two planes.  The Eagle was made for high speed work.  Next, look at the tails and tell me what you notice is different between the rudders on the Eagle vs the rudders on the Hornet.  Lastly, the Hornet has FBW systems which can/will ignore pilot input if it will damage the aircraft.  Also look into aeroelastic twisting (this will be relevant to the rudder vs total tail area difference of the two planes).  Is it ACCURATE?  I have no idea.  Can I find engineering reasons why it COULD be?  yes.

[BlackPixxel]

The F-15 simply does not have a damage modell for overstressing the airframe.

 

On the Su-27 deflecting the rudders during high speed flight causes vertical stabilizers to ripp of, on the F-15 full deflection nothing happens because such thing is simply not modelled.

[bies]

There is a good description of F-15C flight control on ED page and how rudder input is being limited with speed and roll:

 

https://www.digitalcombatsimulator.com/en/products/planes/eagle_fc/?PAGEN_1=4

 

 

 

 

[Rex]

thanks guys

[Rex]

On 2/8/2021 at 5:08 AM, Spurts said:

Keep in mind the designs of the two planes.  The Eagle was made for high speed work.  Next, look at the tails and tell me what you notice is different between the rudders on the Eagle vs the rudders on the Hornet.  Lastly, the Hornet has FBW systems which can/will ignore pilot input if it will damage the aircraft.  Also look into aeroelastic twisting (this will be relevant to the rudder vs total tail area difference of the two planes).  Is it ACCURATE?  I have no idea.  Can I find engineering reasons why it COULD be?  yes.

 

 

I know what you're saying, I'm just surprised that the Eagle CAN yaw it's nose left and right 10 degrees+ at Mach 2.  At least it can in the flight model, which I suppose is possible due to the lack of damage.  From the page above, the ARI is disconnected at Mach 1, so again, this is what makes it possible to even pull off in the first place.  I'm just surprised the rudders will go out that far at all with 1,000knot wind rushing by them. even without damage, it would take some serious mechanical force.

On 2/8/2021 at 5:11 AM, BlackPixxel said:

The F-15 simply does not have a damage modell for overstressing the airframe.

 

On the Su-27 deflecting the rudders during high speed flight causes vertical stabilizers to ripp of, on the F-15 full deflection nothing happens because such thing is simply not modelled.

 

That's the thing, something does happen ... the nose actually yaws in the direction of the rudder press.  That's what surprises me.  It yaws like an F18 would yaw at 250 knots.  More actually. They modeled that to happen, but it looks like they simply omitted the airspeed calculation, and they have it yaw to a similar degree irrespective of speed.

 

Unless I'm missing something, which is possible.

Edited February 28, 2021 by Rex
typos

[BlackPixxel]

3 hours ago, Rex said:

That's the thing, something does happen ... the nose actually yaws in the direction of the rudder press.  That's what surprises me.  It yaws like an F18 would yaw at 250 knots.  More actually. They modeled that to happen, but it looks like they simply omitted the airspeed calculation, and they have it yaw to a similar degree irrespective of speed.

 

I mean nothing happens in terms of no structural damage. The rudders deflect alot, at that speed it should have consequences as in the modules with a properly done damage module.

[GGTharos]

It would take the vertical stabs off if you deflected them too much (... which is probably not much at all).   The ARI is likely disconnected to prevent exactly that.

Edited February 28, 2021 by GGTharos