A decade or so I was asked to prepare a performance evaluation on the Angel aircraft for operations in PNG. I have been able to find the submission I made at the time and it was far from favourable for the aircraft type.
The single engine ceiling was approximately 3700' at ISA sea level. And that was with an airframe that did not have a HF radio or Van 5/X DME antennae installed and adding to the drag.
Essentially; it was a single engine aircraft at all times in the event of an engine failure. At the time the factory was unable to provide sufficient data to suggest the aircraft would maintain a 1% climb at 5,000 feet for IFR. Indeed for IFR take-off and go-around the MTOW had to reduced considerably for the aircraft to achieve the required climb gradients.
The bottom line was that in ISA +15 at Port Moresby there was no S/E climb available and one shudders to think what negative performance there would have been at Mt. Hagen, Chimbu and Goroka. Maintaining runway heading and banking the dead wing 5 degrees towards the live engine would have been paramount to success.
The aircraft may have appealed to those with a requirement for VFR, short inter island sea level Ops. Just take a look at the wing and the undercarriage; it would make you cringe. I don't know how many were constructed, sold, or now still exist. Even the ownership of the 'Type Certificate' may be questionable.
Many years ago the Piper PA-23 Apache, if fitted with the 150hp engines was CASA/DCA mandated as a single engine aircraft for the purposes of crossing Bass Strait from Victoria to Tasmania. Always via King or Flinders Island. The upgrade to 160 hpp made no real difference either. There was no S/E performance at anything but very light weights at ISA S/L The particular aircraft I use as that example was/is VH-FAD which had a short career in PNG before returning to Australia. The aircraft flew into power lines and survived whilst being owned and operated by Groupair at Berwick, Victoria. The aircraft had an aftermarket 'long nose' conversion which actually aided the performance ever so slightly. Not sure where the aircraft is now.
The "Angels" are now looking after the Angel occupants.