Spin recovery procedure

[skypirate]

Flight model of this thing is good.. Perhaps too good :smilewink:

Last night tried the extreme envelope of the F5 and must say this little thing does spin like no other. The first try I spun from 30K all the way to the ground. The "usual" procedure - stick slightly forward, rudder full opposite, throttle idle - did not work. It just keep spinning and falling, and falling... What started as calm and well measured control inputs, soon became a "try all sort of frantic things" that didn't work. I couldn't believe it how the forest rose closer and closer till I crashed hehehe. Take two - played with the throttle this time. Together with the full opposite rudder tried full opposite thust to try and stop the rotation. Something happened and I recovered losing "only" 15K feet. Back to 30 and tried again. Interesting was that the plane was entering in different variation of spin every time, eventually developing into a flat spin. Crashed again, and again, and again. Couldn't figure a consistent way of spin recovery. Reading TFM didn't really help. Embarrassing as it is I love it. This module is so good..

 

So could someone point out a bombproof spin recovery technique?

Edited July 23, 2016 by BIGNEWY
1.1 profanity

[Flamin_Squirrel]

So could someone point out a bombproof spin recovery technique?

 

The RW manual indicates there's no such thing. It describes the following (my words though):

 

'post stall gyrations' are a precursor to a spin. Recovery should be initiated before the spin develops (reduce AoA with forward stick). If the spin does develop, recovery is possible but becomes less likely as the spin flattens.

 

Spin recovery technique is as follows:

 

1. Stick full forward
   
2. Aileron full in direction of spin
   
3. Rudder full oppsoite
   

 

Just a point to note here, spin recovery procedures are by no means universal e.g. not all aircraft require rudder for recovery.

[AnnaNass]

Where is #2 written?

 

1. Stick full forward
   
2. Aileron full in direction of spin
   
3. Rudder full oppsoite
   

[Flamin_Squirrel]

Page 188 of the F-5E real world manual.

[grunf]

From my observations so far, once you enter the flat spin, the only reliable way to stop the spinning is to hit the ground. :megalol:

[skypirate]

Flamin, thanks for the input.

Tried more aerobatics in the morning. So far that's what became apparent:

 

1. It's not easy to enter flat spin. (I just somehow managed last night to nail it every time)

2. The PSG appears as spin but it's not. Usually controls neutral in the right moment will recover the jet in less than 2K feet.

3. With persistence the PSG develops and the jet enters the flat spin (of death)

4. As manual suggest keep the controls locked with full rudder and full aileron (spring release pressed) to the opposite direction, stick slight forward, maybe play a bit with the opposite thrust too (and pray). It will spin forever until with a bit of luck the jet recovers into a 90 degree dive. If you lose it and start the "try anything to get me out of here" jerking of the controls you can kiss it goodbye. The successful recoveries took more than 10K feet.

5. F5E is not T38, i.e. it's not supposed to be in a flat spin in a first place.

 

Research continues.

Edited July 23, 2016 by skypirate

[FZG_Immel]

From my observations so far, once you enter the flat spin, the only reliable way to stop the spinning is to hit the ground. :megalol:

 

same here.

 

Ive tried getting out of the self induced flat spin, but it doesnt work

[Jansgi]

I tried multiple times a flat spin recovery and survived every time. Even tried as low as 5000ft and survived with couple of feet to spare.

 

1. Flaps up

2. Stick full forward

3. Rudder full to the opposite of the spin

4. Ailerons full to the direction of the spin (press aileron limiter on the stick for more aileron authority)

5. Survive

 

Just be aware that manual says to put flaps to AUTO, but in my case it made it worse.

Edited July 24, 2016 by Jansgi

[Maverick Su-35S]

Because it's very likely that few people know why is the aileron used towards the spin and why should the stick be pulled in general (NOT PUSHED) until the yaw rate gets low enough to offer the desired responsive controls and completely stop the spin, we will discuss how does the aileron increase and/or decrease the local Angle Of Attack on the wing along which the aileron spreads, knowing the consequence that a longer aileron with a higher area also gives a higher desired/non-desired effect.

 

We know that increasing angle of attack we increase both lift and drag and while the lift increases linearly the drag increases exponentially (increases much more). The drag increase due to AoA increase is generally an inconvenient, but not for spins though. Asymmetric drag between the wings and/or rudder lift towards left or right (left or right rudder inputs) is what generally induce a yawing moment which can develop into into a spin at angles of attack higher than stall, while a higher drag generated on both wings combined with rudder input is a great ingredient that helps to get out of the spin or at least decay the yaw rate well enough to lower the AoA up to a level where the controls respond normally. On aerobatic aircraft with high aileron span and surface, getting out of a spin can be easily done even with rudder neutral by just applying full aileron towards the spin, not neutral or opposite. Never use aileron opposite to spin or you could possibly hold your plane (any plane) there forever.

 

Imagine that you are in a rightward high yaw rate spin (above 50 deg./s.) at very high AoA. By applying full right aileron (towards spin), both ailerons will increase the AoA of their wing, not just one. The right aileron rises, but the right wing's AoA along the right aileron will increase instead of decrease because the airflow is now coming from behind (the right wing has negative airspeed or flies backwards so to say). The left aileron lowers and the left wing's AoA along the left aileron increases as long as the airflow is coming from the front, which normally happens.

 

So, when you apply aileron towards the spin, you increase the AoA for both wings and generate higher wings drag which is crucial for reducing the yaw rate which is the greatest enemy in a spin. If you would ever use ailerons opposite to spin, as a rookie might naturally want to, you would only worsen the situation because the AoA on both wings would be lower enough so that the generated drag might become null and the spin becoming non-recoverable. Generally, the rudder input isn't enough of alone and it's the ailerons which in many cases offer a higher desired beneficial yawing moment that reduces the spin.

 

Look at fighter test pilots also on how they use the ailerons to enter and get ouf of a spin, cause they know these effects very well.

 

Here's an example:

 

 

As you can see, he induces the spin using ailerons opposite to the desired direction of spin and when told to recover he immediately applies full stick towards the spin and the yaw rate already starts reducing. The fact that the F-18 started tumbling upside down when the yaw rate started to decrease is something specific to the F-18 due to it's general aerodynamic configuration, but the aileron towards spin was essential.

 

Great day!;)

Edited December 23, 2016 by Maverick Su-35S

[Maverick Su-35S]

Just be aware that manual says to put flaps to AUTO, but in my case it made it worse.

 

Totally agree, and it's not the first time when manuals needed rework because they killed people as the data was inaccurate. At higher AoA and higher yaw rates, the lowered the flaps are the worse the spin becomes. Everyone can test this on Su-25s, A-10s or any other plane that a lowered flap will tend to keep you spinning or reduce the chance of lowering the yaw rate in a flatpsin, so it's a true fact that flaps should be zero or negative (gliders have negative flaps) in order to get out or get out quicker.

[Flamin_Squirrel]

...and why should the stick be pulled in general (NOT PUSHED)

 

Why have you necro posted an old thread to post incorrect information? If you'd actually read the thread you'd have known the above is wrong.

[Figaro9]

I think mav knows what he is talking about. Beside gliders I flew the pc7 and the dh115. And the spin recovery looked always about the same: 1.idle 2.gear/flabs up 3. Pull (not to enter inverted spin) 4. Direction of spin 5.rudder opposite 6.stick neutral 7 rudder neutral 8. Recover. Quite sImilar to the F5 bold face for inverted spins...

You push only just before entering spin, if you are sure not to enter inverted spin or in high_g spin situations.

I was in a inverted spin only once and my ip was not very amused...

[Flamin_Squirrel]

I think mav knows what he is talking about. Beside gliders I flew the pc7 and the dh115. And the spin recovery looked always about the same: 1.idle 2.gear/flabs up 3. Pull (not to enter inverted spin) 4. Direction of spin 5.rudder opposite 6.stick neutral 7 rudder neutral 8. Recover. Quite sImilar to the F5 bold face for inverted spins...

You push only just before entering spin, if you are sure not to enter inverted spin or in high_g spin situations.

I was in a inverted spin only once and my ip was not very amused...

 

This thread is about spin recovery in an F-5E (at no point was inverted mentioned). The procedure for this was devised by test pilots and written clearly in the manual.

 

If you think they're wrong, or want to talk about other aircraft, why not start another thread rather than confusing people?

[Figaro9]

Right, the threat is about spins (at no point was erect mentioned neither) There are different types of spins. Not talking about the inverted spin does not mean that it does not exist.

According to the Flight manual: Only push if you are sure not to enter inverted spin, if your not in an inverted spin or to avoid stall at all.

I do not think I confused people in this forum. I tried to be as precise as i could and shared my lowly know-how and experience.

Reality may be confusing. While no time in the air to discuss aerodynamic topics and personal experiences, here in the forum we should have (without being insult by self-declared keepers of the grail). Than back to sim, try it out. Maybe there is even a peanut for squirrels to collect...

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980227417.pdf

Edited December 26, 2016 by Figaro9

[Flamin_Squirrel]

According to the Flight manual: Only push if you are sure not to enter inverted spin, if your not in an inverted spin or to avoid stall at all.

 

It says no such thing.

 

 

Reality may be confusing. While no time in the air to discuss aerodynamic topics and personal experiences, here in the forum we should have (without being insult by self-declared keepers of the grail). Than back to sim, try it out. Maybe there is even a peanut for squirrels to collect...

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980227417.pdf

 

If you make statements that directly contradict what's in the flight manual, be prepared for people to call you out on it, and don't expect any sympathy if you take it personally.

[Figaro9]

To make it finaly clear: (literally) out of F5E Flight manual III-15

 

(Do not push in inverted spin)

1. Flabs up

2. Stick aft (as required)

3.ailerons and rudder neutral

 

(Push to avoid stall/spin)

If relaxing stick is not sufficient...

1.stick forward (as required)

2.rudders ailerons neutral

... in most cases ... stick position forward of trim will initiate recovery.

... failure to relax stick on recovery may cause inv. psg/spin...

 

(Push in erect spin)

1.stick full forward

2.aileron full in direction of spin

3.rudder opposite

...

 

To complete the picture (only for nerds who can stand confusing things and a headache):

Nasa recommended technique for best possible recovery from fully developed erect spins (see attachment above):

1. Stick longitudinally neutral

2 & 3. as in Flight manual.

 

Inverted spin

Symmetric load

1.neutralise controls

Asymmetric load

1. Stick full back

2.rudder full against spin

3.aileron full against spin.

 

Many things to try out. For curious people only.