August 2022
This would be an interesting subject for an article describing the TFE731 development. It is rumored the engine was developed from an APU power-plant. I recall when our flight dept operated early conversion applications in which the 731 replaced first-generation turbojets on DH-125 and Lockheed Jet-Star first-gen jets. Jet fuel back then was 50-cents per gallon and the main reason to consider the conversion was not fuel costs but improved range and noise. At that time interest-rates were running in the 8-12% range and so the interest on the $3M conversion cost would pay for all the fuel burned by the older engines. At that time the 71s were also suffering a high rate of fuel pump/control failures, and when the Jet-Star conversion was being considered for the Jet-Star our parent-company CP (who was hoping the company to replace the Jet-Star with a G-II) was overheard to say “I’d rather fly across the Atlantic on one Spey than four 731s.”
The TFE-731 has come a long way since then.
3 replies
August 2022
▶ gahorn146ys
I meant to also say that the first time I ever flew the “pond” was in a 731-converted 125 using Omega/VLF…another 1970s/80s “high-tech” item which the 731 outlasted in fine form.
1 reply
August 2022
An interesting back story concerns the origins of the engine at Garrett AiResearch, its founder Cliff Garrett and the genius of his turbine expert, Walter Ramsaur. Born in Shelby, NC, Ramsaur was from a family known for its construction and operation of mills (the first rotating machinery) on the many streams flowing eastward down from the Blue Ridge Mountains. The family heritage goes back to their homeland in the foothills of the Bavarian Alps where mills are also driven by Alpine streams. Both Garrett and Ramsaur were self-taught engineers with numerous patents on rotating machinery. Garrett used this to pioneer the development of turbochargers used worldwide in vehicles.
August 2022
▶ gahorn146ys
I laughed when Air Canada put modified turbine wheels into the DC9’ APU instead of the supposedly better new design, that tweaked Airesearch’s nose.
It took many years of new executives to turn the company around.
(Airesearch in Phoenix being the predecessor of Honeywell’s turbine engine division.)
August 2022
▶ gahorn146ys
Goodness, you go back as far as I do. 
Omega was never realized because ground station network was not completed. Canadian Marconi’s receiver was very good.
VLF was a bad idea - it used US Navy submarine communications stations, but they could be switched to airborne transmitters especially in war time.
Both very powerful stations, if you hike Jim Creek valley in the north Cascades in WA you are in the former site of one VLF transmitters, though beware USN may still practice ridge hopping with A6s there.
VLF operated about 30KHz to penetrate water, Omega closer to 10KHz (the inside of an Omega receiver looked like a computer full of circuit chips).
Inertial Reference System navigators were very expensive in comparison.
August 2022
▶ gahorn146ys
