G'day Glenn,
I hope the following narrative helps in relation to your search for 'black and white' data in the never-ending seas of grey when it comes to trying to piece together the Aero Commander airframe lineage and variations.
As you have discovered with your research there are many anomalies in relation to the details quoted (in various forums and 'sacred' sites) for specific Models and indeed specific individual examples of Models over time.
The very best analysis of this often conflicting information is documented in the
www.twincommander.org 'Models' section (free for all to access) - Barry Collman (author of these Model files) has amassed an amazing 100,000 item strong database of files (many retrieved from deeply stored FAA records) through a lifetime of visits to the FAA archive office in Oklahoma City, various repositories of original Aero Commander/Rockwell Commander/Twin Commander Factory records and including what the current Twin Commander Aircraft Corporation (TCAC) holds on file.
Indeed the TCAC defers to Barry when it comes to resolving some of the historical anomalies that it is faced with from time to time.
680F(P)
In regard to the Aero Commander 680F(P), as you have discovered - reference to it as a 680FP, 680F(P) and/or 680F(p) can be quickly found depending on where you look.
Undoubtedly, Moe Mills relied on the specific logbook airframe entry in choosing the 680F(p) [lower case 'p'] nomenclature when determining what he was going to display up on the wingtips, when he repainted the airframe a few years ago. I remember him wryly commenting on his choice at the time - BUT - undoubtedly he was using the reference as written in his airframe (now yours) Logbook #1. Who knows why an engineer used this [lower case 'p'] terminology early in the life of N680RR.
Barry Collman has often found that the UK CAA nomenclature conflicts with what the FAA holds on record, but in the end the purist way to refer to it is using the 680F(P) derivation.
The 680F(P) was not listed by the manufacturer on a Type Certificate Data Sheet No. 2A4 (as it did for other stand alone Models), but the 680F(P) was approved by the FAA on 29 June 1962.
Over time 47 Model 680F airframes had an optional pressurisation system installed and were referred to as the Model 680F(P).
A manufacturer's document describes the Model 680F(P), under Wing Drawing 5170045, as a "pressurised 680F and as such is identical to the 680F except for cabin pressurisation and modification in accordance with Aero Commander Drawing 6100021, Change A. Certified in, per CAR3, 15 May 1956, Amendments 3-1 thru 3-4".
The Model 680F(P) can be visually identified by having a dorsal scoop on the top of the fuselage, just aft of the wing trailing edge and the pilot's Direct Vision, or storm port in the cockpit side window, being suitably strengthened or deleted.
Five Model 680F(P)s were converted to the Mr R.P.M. "Turbo 800" under STC SA2891WE with 400H.P. with Lycoming IO-720-B1B engines, Rajay turbochargers (STC SE62WE) and 80.625 inch diameter Hartzell HC-A3VK-2A/V8433-4R propellors.
Barry has painstakenly researched the FAA files for every individual airframe and thus his database has no contemporary equivalent.
Determining how many of the 47 airframes are still flying or still with functioning pressurisation systems would be a significant challenge - you would need to combine Barry's individual records, the current FAA (or international country equivalent) records with an approach to the individual owner!!
680FLP
Only 38 examples of the Model 680FLP were produced.
In regard to the Aero Commander 680FLP - reference to it as a 680FLP, 680FL(P) and/or 680FL(p) can be quickly found depending on where you look - take care!
Caution - of these, s/n 1261-1 was later converted to a Model 680FL (s/n 1261-108) and s/n 1473-3 was converted to a Model 680T (s/n 1473-1).
Three examples have since 'officially' been recorded as having had the pressurisation removed (including one in Australia which was subsequently referred to as a 680FL(P).
Strangely - early manufacturer records refer to this Model as the 680FPL!
The Model 680FLP is a pressurised version of the 680FL and is identical structurally and aerodynamically to the 8500lb Model 680FL.
Thirteen Model 680FLP examples were modified to Mr R.P.M. 'Turbo 800' Model under STC SA2891WE with 400H.P Lycoming IO-720-B1B(D) engines, Rajay turbocharger (STC SE62WE) and 80.625inch diameter Hartzell HC-A2VK-2A/V8433(N)(B)-4R propellors.
Visually, the Model 680FLP has the same dorsal scoop as the Model 680F(P).
The 'beaded' or 'corrugated' control surfaces were used up to and including s/n 1527-24 and from s/n 1527-25 they became 'smooth' or 'flat skin' type.
Determining how many of the 33 airframes are still flying or still with functioning pressurisation systems would be a significant challenge - you would need to combine Barry's individual records, the current FAA (or international country equivalent) records with an approach to the individual owner!!
Cheers
Russell
