Would the benign spiral maneuver be one alternative to dealing with being "stuck above" or inside a cloud? Recently I provided an alternate answer to a question involving "hands off" recovery techniques.  In this I briefly illustrated the benign spiral maneuver.  For completeness I will reiterate what I said in that answer:

This (benign spiral) maneuver is considered to be the safest way of recovering in a glider when one has found themselves above a hole-free cloud layer or inside a cloud.  My club teaches this maneuver as part of initial glider pilot training, though it is not (yet) part of the US FAA Glider Practical Test Standards.  

The steps my club recommends are:


Full spoilers
Trim slightly aft (Other references suggest 1.5 times the stall speed)
Hands off stick
Feet off rudders


The effect of this maneuver is the glider will settle into a gentle spiral with a roughly constant (and not load-exceeding) airspeed and altitude loss.  The maneuver is also taking advantage of the aerodynamic stability mentioned in other answers which is inherent in most (all?) modern gliders.

Here are some additional sources that discuss this maneuver:


Scottish Gliding Centre's Airfield Procedures, Page 17 - 18
This post, which quotes "Transition to Gliders, A Flight Training Handbook for Power Pilots" by Thomas L. Knauff. 


That got me to thinking about whether this technique would be applicable to recovery from the same situation in a powered airplane.  Being "stuck above" or even inside a cloud has certainly been the cause of accidents.  One harrowing story that really hit home for me is told in this video from the Air safety institute.

So, my question: Would a benign spiral be one alternative to dealing with being "stuck above" or inside a cloud?  Lets assume for the sake of argument that the airplane involved is a typical single-engine, forward prop GA aircraft (e.g. Cessna 172, Piper Cherokee, etc.)
It works in most gliders because they tend to be neutrally stable in roll and - the big one - have speed limiting spoilers/dive brakes.  I'm not sure it's safe to do that in an older glider without speed limiting spoilers.

In any case, most power planes, once disturbed beyond the ability of dihedral effect to restore level flight, will naturally descend in an ever steepening spiral without pilot input.  There aren't any ways to limit the speed on a GA power plane (gear and flaps won't cut it) the way spoilers/dive brakes on a glider can.  It would need a speed brake that can hold the plane to below Vne in a vertical dive.