Inverted spins
 

Back in the way distant pass (really, a long, long, time ago), at a time when spinning was part of the PPL training, I frightened the pants off my instructor on a refresher flight by nearly putting the a/c (C150) into an inverted spin.

To this day, I have never understood the difference, what I did wrong, nor why it was so bad (he said it was unrecoverable). I have never spun an a/c since then (despite having asked some FIs – all of whom quickly find reasons for not doing them!).

Can anyone elucidate on why it would be not recoverable, and what was I doing wrong in the first place?

The spinning technique taught at the time (IIRC) was power back but not off, nose well up with speed dropping close to stall, then pull back and apply full rudder. Hold controls in position as a/c enters the spin, count the turns and recover.

GB
(Before you all warn me, I don't intend spinning any a/c in the future, unless under proper supervision :D )

IMHO it is extreemly unlikely that it was an inverted spin. If you have the stick back on entry then the spin should be an erect one no matter what your attitude at the time, to get into an inverted spin you need the stick forward, very difficult to enter inverted on a C150 from normal attitudes,it might flick inverted on entry but if the stick is back then it will still be an erect spin.
The only time I have done an inadvertant inverted spin (not a 150), was from a vertical roll to be followed by a stall turn - stick forward at the end of the roll and rudder in for the S.T.
I do not know about the 150 inverted spin (anyone been there - even a Test Pilot?)but see no reason to say it is impossible to recover from.
If you can get to the UK I would recommend heading for UH at Kemble as they specialise in this sort of training and will be happy to spin you both ways up.
:eek:

Cross-over inverted spin entry through botched recovery from the upright spin? - no idea if a C150 will actually do this though.

Erect spin - spinning the 'right way' up

Inverted spin - spinning 'upside down'

Unless you're doing some aerobatic training or whatever, spins will be erect. As Fox says, you need to make different control movements to enter an inverted spin compared with an erect spin so unlikely you would go for one and end up in the other by accident on entry. On exit may be a different matter, but someone more qualified than I am can probably explain that bit.

Either spin is recoverable - as long as you make the right moves. Some spins may take longer to respond to control inputs, which is where the myth that inverted = unrecoverable may come from. It takes some patience and discipline to stay with recovery inputs that may not work immediately, especially if you're not used to being in unusual attitudes and are losing altitude faster than you've ever seen before!

I suppose that might be possible - but would be a hell of a bunt to achieve which I am sure would have been noticed, perhaps groundbound can tell us if it was on entry or recovery that this was supposed to have occured and did he notice a lot of negative G on recovery?

NO NO NO!:ugh: :ugh:

Very simply:

An erect spin is caused when positive alpha is exceeded and a wing slows sufficiently as not to cause lift.

An inverted spin occurs when negative alpha is exceeded and a wing slows sufficiently as not to cause lift.

So I can be upside down in attitude, pull the stick back TOO far, hoof in some rudder and I will be spinning errect.

I can be upside down and push TOO far, hoof in some rudder and be spinning inverted.

I can therefore be upright and push - voila inverted spin as critical -ve alpha exceeded.

Recovering after an inverted spin on hdg outfoxes me!

I thought you were trying to sort this out???:)

Good luck this weekend

If you are inverted and pull, surely you will exceed -ve alpha crit? What am I not understanding?

No, to exceed negative critical AOA from inverted you must push.

There is just no way I can see getting a C152 to spin inverted without completely bizarre pro inverted spin control inputs....even a crossover spin would require full forward stick and I suspect you be more likely to rip the wings off in an inverted dive before reaching/exceeding the required AOA.

I used to get perverse enjoyment inverted spinning Decathlons....they do them really well...they're a lot more violent than an upright spin but in the Decathlon completely straight forward to enter and exit.

Have done a few in Pitts and found it very interesting that you can see the horizon over the top wing inverted and normal spinning...the difference as pointed at to me was inverted spinning you're hanging in your straps and can see the point about which you're spinning...a difference which in the heat of the moment has not been evident to some with fatal results....apparently.

Isn't it true that in an erect spin the roll and yaw directions are the same and in an inverted spin the roll is in the opposite direction to the yaw?

I was under the impression that this was the difference / definition as well. Nothing to do with how one got into it / which way up you were.

OC619

P.S. Ready to be corrected / abused / whatever :O

In an inverted spin. Left foot, makes right aileron inspin (All from the pilots perspective) Right foot, left aileron. Niel williams book has some great drawings that explain the logic.
Stall turns can very easily produce inverted spins.......
In erect spins (Lycoming) left foot is flatter, whereas right foot is steeper and faster.
Inverted (Lycoming) Left foot is faster and steeper.
After a while they become easier to stop on heading than errect, due to the fact you can see the axis above you at all times.
Inverted spins can have behave differntly from type to type because of the blanking effect of the tailplane on the effective rudder. (Better Aerobatics by Uncle, and Xavier book on the 4 minute free explain better than me.)
Again these threads tend to always up in the same message. Spinning is not a black art, but a manuoevre that requires specific training demonstration, and practise.

Correct but in an inadvertent spin identifying the difference can take time. If the a/c has a slip needle, it will always show yaw direction regardless of inverted/erect and the correct course of action would be to press the pedal furthest from the needle tip.

Absolutely!!!

Stik

Aye....but the two point roll in your Free, now that's a black art....eh? :ok:

And for any of you folk who have not seen an inverted spin, you'll find a whole bunch of chaps and chappesses doing them at Fenland from lunchtime today until cop Sat.


Stik

eharding - what time you arriving?

Just about to jump in the car.....about 5pm....see you later!

as mentioned earlier , Inverted spins are no more a big deal than erect spins, and once you experience one, and then go on to get more comfortable with them, you'll wonder what all the fuss was actually about.

I am not a huge fan of crossovers because of their confusing and initial violent nature, and I dunno about most here, but I think its easier to come out on heading on an inverted than an erect accelerated...............:uhoh: just look up!

luck has alot to do with it I admit :uhoh:

That's the case with MOST of my manuevers! :)

Thanks for the replies, guys. Not that I understood much - just shows how little I know :(

As this was a long while ago, and in the early stages of training, I don't remember much. I was trying to put it into a spin, using the flick entry we were taught, when the instructor shove urgently forward on the stick, accompanied by a strangled gasp - followed by the above explanation.

Foxmoth, Ultimate High is my target if I can find the time and money :eek:

Dont know if this will help, its me do an inverted spin at ultimate high a couple of months back

www.inosys.co.uk/invertedspin.wmv