Spinning a C172

[9 lives]

I'm a bit surprised that you'd put the C150 and C172 in the same category.

Fair enough, I was thinking more of their similarities in recovery than entry. Yes, the 172 is happily difficult to get in, as a four place general purpose aircraft should be.

For my experience, 150/152/172 all respond reasonably well to the "let go and wait" technique for spin recovery, where others I have spun will demand to be promptly and precisely recovered. I've only heard about other spin approved aircraft which demand a good recovery technique, I've not flown them....

[India Four Two]

I didn't anticipate that my question would generate quite so many responses.

I'll have to go and spin a 172 and see if it is like I remember. In the meantime I had a look at Youtube. Lots of 172 spins, this is the best one I think:



The instructor leaves some power on for the entry, which is something I don't remember doing. I like the student's honest reaction at the end of the first demo spin: "Holy cr*p!"

[ANOpax]

This year, after a eight year absence, I am back in Canada and will be flying much more modern two-seaters this year - ASK-21, DG-1000 and DuoDiscus. I'm looking forward to seeing how they spin and more importantly, how they recover. Being very low-drag, they accelerate very quickly when pointed downward.

At the risk or raining on your parade...

Duo's aren't cleared for spinning AFAIK (due to a tendency to go through Vne in the recovery, I'm told).
K21's won't spin unless you have the spin kit fitted - they end up in a spiral dive.
DG-1000's spin and recover beautifully. A favourite trick of one of my club's instructors is to brief a spinning and stalling sortie in an aft CofG ballasted DG-1000. He'll ask the student to demonstrate a gentle stall and at the buffet he'll apply full rudder. Spin entry is guaranteed (and so is a surprised student!).

[India Four Two]

At the risk or raining on your parade...

ANOpax,
Don't worry, I have an umbrella.

Thanks for the information. I didn't know about the Duo spinning restriction, which is ironic, considering I have 17 hours in it, flying dual cross-countries in the Southern Alps. However, since I wasn't going to be going solo, the issue of spinning and/or reading the handbook didn't come up. I do remember one stall "attempt", which was more "slow flight with high ROD" rather than a stall.

On the other hand, I have never even seen an ASK-21 or a DG-1000! However, I am intimately familiar with their handbooks, because I have just been teaching at a ground school, where my topic was weight and balance and why the CG limits are specified. Our club uses the ASK-21 as its "basic" trainer and they do have the spin weights and they routinely spin it.

I think the idea of an instructor surprising a student is not a very good instructional technique. If I wanted to demonstrate the DG-1000 behaviour that you describe, I would brief the student and then demonstrate it or if the student was reasonably competent, have him do it.

As an aside, I found the manuals for both gliders very poorly written and confusing. After looking at the originals, I concluded that it wasn't just a case of poor translation. In the case of the DG-1000, looking at weight and cg ranges specified in various places, it is hard to determine what is recommended versus being a certificated limit. The latest version of the ASK-21 handbook has an addendum, containing a USAF document about the spinning characteristics, because the USAF clearly felt that the manual was not satisfactory.

[Big Pistons Forever]

Originally Posted by ANOpax

He'll ask the student to demonstrate a gentle stall and at the buffet he'll apply full rudder. Spin entry is guaranteed (and so is a surprised student!).

Does the Chief instructor at the club know what this idiot is doing ?

[ANOpax]

I think the idea of an instructor surprising a student is not a very good instructional technique. If I wanted to demonstrate the DG-1000 behaviour that you describe, I would brief the student and then demonstrate it or if the student was reasonably competent, have him do it.

I'd agree and I'm at fault for not being sufficiently clear - by student, I meant P2 on our biannual refresher training. So I guess the issue for the instructor is 'how do you assess P2's competency in spin recovery if P2 is the one being asked to spin the glider in the first place'. I admit to being taken aback the first time it was practiced on me. I think the advantage of this instructing technique is that P2 has to actively think about the use of contra-spin rudder rather than practice the reflex of simply applying opposite rudder as is normally the case when the spin is P2 initiated.

I'm sure you'll enjoy flying the K21 and DG-1000. Both great flying machines (as is the Duo).

[Big Pistons Forever]

Originally Posted by ANOpax

So I guess the issue for the instructor is "how do you assess P2's competency in spin recovery if P2 is the one being asked to spin the glider in the first place".

The refresher training should not be concentrating on spin recovery, it should be concentrating on spin recognition and avoidance. More than 50 % of all glider stall/spin accidents occur at or below 400 feet AGL. If you let the glider get into a spin at that low an altitude it doesn't matter how good your spin recovery technique is ......

If I were conducting the refresher training I would first demonstrate the classic over banked, stick back pressure, inside rudder, base to final stall and spin entry. I want the student to be totally familiar with what this deadly and all to common scenario looks and feels like. I would then get the student to fly the same profile and then recover when the aircraft departs into a spin.

I also feel strongly that unless you are teaching aerobatics any spin allowed to progress beyond a 1/2 turn is negative learning. What you want to impress upon the student is the necessity of immediate recovery and not letting the aircraft wind up and therefore lose a lot of altitude.

By the way what I have said above applies equally to powered aircraft training.