Hi guys. I would like to scratch the subject of Model 1100 a bit. I dig out its FAA type certificate (
>>H2WE<<) and there is clear distinction of models as follows:
- Model 1000: 4 person helicopter powered by Allison 250-C10
- also kind of includes US Army OH-5A (engine named as T63-A-5)
- Model FH-1100: 5 person helicopter powered by Allison 250-C18 or Allison Model 250-C20B (after certain mod.)
Interesting is Note 5: If I am understanding it correctly, it says that Model 1100 as an ARMY OH-5A is actually bit different, and could be converted later to the certified state.
So, for me, there were three different variants: OH-5A, Model 1100 and Model FH1100.
I guess that model 1100 was still envisioned before Hiller was taken over by the Fairchild - that happened on May 7th, 1964, and the type certificate was granted on May 22nd, 1964 - clearly it was process of at least dozen of months of duration at that time.
Then, following this line of thought, the FH-1100 was a Fairchild's push to increase its performance (one more person on board).
Now I am trying to identify those variants on pictures. It is easy for FH-1100 - as several of them were built. Also well known is form of the OH-5A (or rather YOH-5A), as it is documented on pictures from its Army trials. Problem is with the Model 1100 as a civilian helicopter. So far I found one picture most likely showing that model, but described as FH-1100. Yet another picture clearly shows similar (or very same) helicopter, just with slightly modified cowling and writing FH1100 on it (although it is S/N 2).
I compiled a little chart with visual differences per variant as I perceive it right now (attached).
Am I right?