Aerobatics - The Mulleroid (Zwilbelturm) in a DR107

This video is for entertainment. I am not an instructor.
The figure flown here is best known as the Mulleroid in honor of Eric Muller who called it the Zwilbelturm in the book Flight Unlimited that he coauthored with Annette Carson.
It is a relatively easy figure, that is comfortable for the pilot and not unduly stressful on the airframe or engine, being on par with a spin or snap roll.
It can be flown on its own or blended in with various rolls. Here I chose to blend it in with some vertical rolls as they provide a good segway to the mulleroid.
Be very comfortable with flat spins before attempting this figure.
Also ensure that you have plenty of altitude to recover. The figure involves flat spins and consequent loss of altitude. In the video the typical altitude before the pull up was 7000 feet and the minimum altitude was 5000 feet after two or three flat spins and some rolls.
With regard to handling of the throttle. This plane has a constant speed prop, set at 2500 rpm. Handling of the throttle may differ with a fixed pitch prop.
I would suggest that you determine beforehand how many spins and rolls you will do and be well versed with the associated altitude loss. Also be spring loaded to abort the figure if you loose count!
Since I am starting with some vertical rolls, some conversion of altitude into speed is required. The quicker we are travelling, the more vertical rolls we can stuff into the combined figure as part of a routine. Here a speed of about 160 knots is used.
Pull to vertical and start the right roll.
Smoothly and progressively feed in left rudder, right aileron and forward stick - simultaneously. It is also possible to start this with a left rudder snap roll but that works best with planes that have an abundance of power, such as the Extra 330SC, MXS or the Sukhoi’s.
As the airspeed decreases, gyroscopics take over and the plane pivots about the vertical axis as the nose drops. This is the start of the Mulleroid.
When the nose approaches the horizon, the stick is moved to the full aft position, maintaining left rudder and right aileron. Depending on how gyroscopics affect your particular aircraft, it might improve matters if the throttle is retarded momentarily before and during this transition to aft stick. In the case of the DR107, I’ve found that full throttle through out the figure works best.
You may also find that you can keep your wings level with the aileron, in my case, I usually end up with the aileron held hard right.
As the nose drops though the horizon, the controls are now in the perfect position for a flat spin to the left. That is full aft stick, full right aileron, full left rudder and full throttle.
After a half turn or so, the plane will settle into a flat spin, that is held for a turn or two.
In the case of the DR107 and many high-performance monoplanes, recovery from the left flat spin can be executed by applying full right rudder and moving the stick from the right aft quarter across to the left aft quarter and then forward.
This allows the Mulleroid to be seamlessly followed up with some left vertical rolls as is done here.
Have fun with it and don’t break the plane!