M-1 vs. F-1

[cjackson]

Which engine was more powerful? Does footage exist of M-1 testing?

[Jeff Root]

What was the M-1 ? A USA engine? Whether it was USA
or USSR, if it was supposed to be more powerful than the F-1,
then I'm sure it was never test fired, and none was probably
ever built that was ready to be test fired, though full-scale
nonworking models are possible. The STS SRM is the only
engine I know of more powerful than the F1.

If it was supposed to be less powerful than the F-1, then you
know more about it than I do, and I'll shut up and read....

-- Jeff, in Minneapolis

[Jeff Root]

I see that the Wikipedia page on the M-1 shows that it was under
development by the US Air Force and Aerojet in the early 1960's.
It was supposed to have the same thrust as the F-1 finally had,
1.5 million pounds force, burning hydrogen for use as a second
stage engine. The first sentence of the article says that it was
"component tested". I think that means it was never test fired,
but I'm not at all sure.

-- Jeff, in Minneapolis

[NEOWatcher]

I was going to say that the answer is simply found in the first paragraph of the M-1 wiki page.

Aerojet's M-1 was the largest and most powerful liquid hydrogen-fueled rocket engine to be designed and component tested. The M-1 offered a baseline thrust of 6.67 million N (1.5 million lbf) and 8 million N (1.8 million lbf) as its immediate growth target. The M-1 was larger and more efficient than the famed F-1 that powered the first stage of the Saturn V rocket to the moon.
Thrust (SL) 1,500,000 lbf (6.67 MN)
Chamber pressure 1,000 psia
Isp (SL) 428 s

Larger and never tested (only the components were)

But; it gets a little fuzzy looking at the F-1 wiki.

Thrust (SL) 1,522,000 lbf (6.77 MN)
Chamber pressure 70 bars (7,000 kPa)
Isp (SL) 263 s (2.58 kN·s/kg)

M-1 baseline was lower thrust, but higher Isp.
I'm not sure how the growth of the M-1 could have faired against any growth of the F-1, although they do say the F-1A would have had a 2M lb thrust.
Also; the baseline thrusts were the same. The 1.522M was an upgraded engine.

And; we are talking about a planned engine vs one in actual flight.

[cjl]

I was going to say that the answer is simply found in the first paragraph of the M-1 wiki page.

Larger and never tested (only the components were)

But; it gets a little fuzzy looking at the F-1 wiki.

M-1 baseline was lower thrust, but higher Isp.
I'm not sure how the growth of the M-1 could have faired against any growth of the F-1, although they do say the F-1A would have had a 2M lb thrust.
Also; the baseline thrusts were the same. The 1.522M was an upgraded engine.

And; we are talking about a planned engine vs one in actual flight.

I'm guessing that by "larger", they actually mean physically larger, not higher thrust. As you point out, the design thrust points, both baseline and growth targets, are very similar. However, for a given chamber pressure and thrust (both of which are quite similar between the M-1 and F-1), a LH₂/LOX engine will be significantly larger (purely in terms of physical dimensions) than a LOX/kerosene engine.