I made the mistake of looking at your reply after a couple glasses of wine:)
I wanted to find an actual FPS of flame propagation and turned to the internet for a quick answer, which wasn’t there.
OK into the attic to find my old notebooks. My LNG notebook was refilled with the an EMT class and a microbiology class.
I set aside the EXXON VALDEZ report along with the sinking of the TEXACO OKLAHOMA, the Neahkani Mountain exploration by Captain Drake, pilotage classes for Prince William Sound.....
Opened my 8th edition of Standard Handbook for Mechanical Engineers ($64..50, 1978) Depending on per cent in primary air-gas mixture, looking at the graph, top speed :) :) 1.5 FPS
Happy New Year
WOW! And you did that all on two glasses of wine. Impressive.