By: J Boyle - 16th July 2014 at 19:19
Here’s what the factory told me….
In the early 1980s Hughes proposed some optional product improvements for the 369F (mostly for external load operations). Hughes called the helicopter with these performance improvements the 369F+ (marketing designation). The FAA determined that these changes were “significant” and therefore required a model designation change to the 369FF. The production line was rolling and 20+ 369Fs were delivered to various customers around the world and our customer support personnel were tasked to make the necessary mods (see note 12 on the H3WE TCDS) and attach an additional data plate designating the helicopter as a 369FF. The goal was to convert all 369F to 369FF. Unfortunately a couple conversions were not documented or never done therefore we were forced to include the 369F in most service documents hence forward.
Basically Hughes increased the 5 minute shaft horsepower limit from 375 to 425. The corresponding 5 minute torque limited was increased from 327 ft-lb to 371 ft-lb. (this required a new torque gage with correct markings and a placard 50 KIAS limit).
Hughes also required a new drive shaft interconnect and Kamatics couplings.
By: Simon Beck - 2nd July 2014 at 05:33
Thank you that was exactly what I was looking for, an excellent website as well with what looks to be accurate data.
Most of the 369F’s went to the Iraqi AF which is perhaps why it isn’t well known in civil circles.
By: tenthije - 1st July 2014 at 22:05
According to below site “The 369FF is basically a 369F with an up-graded drive system.”
By: J Boyle - 1st July 2014 at 09:52
Good question…the designations seem to be used interchangeably.
On their own website the firm lists documents for the FF but only lists the F for sale.
My guess is it may have something to do with an option…perhaps the FADEC engine?
At any rate, I sent MD helicopters sales staff an email asking the question.
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July 1, 2014 at 3:45 am