[Goose]

Some more information on Ukraine's new cruise missile. They are using a lot of "off the shelf" tech- turbofan engines from L-39 jet trainers, and warheads from Soviet FAB gravity bombs.

Commentary online suggests this could allow a large number to be built from existing stock quickly, but that further production of the engines could then be a limiting factor once the readily available supply dries up. There are many thousands of those L-39 jets in service (~10k),

Not so sure about that number. https://en.wikipedia.org/wiki/Aero_L-39_Albatros says 2,900 (total) were built. Ukraine operated a number of them, but nowhere near even 1,000 of them

but production of new turbofan engines will be tough to hit their 3,000 per year goal.

Possibly. However if they don't use the Ivchenko AI-25TL but rather its contemporary substitutes e.g. Garrett TFE731 (https://www.code1aviation.com/731) or the Williams FJ44-4M they may be able to simply buy them in the required quantity.

Also suggestions that the range (3000km) and speed (850-900 km/h) estimates originally shared are perhaps ambitious with this engine though of course it is possible the engine has been modified from it's typical commercial version.

https://x.com/John_A_Ridge/status/1958636077792592213
https://x.com/John_A_Ridge/status/1958562813699309817

IMO both the range and speed estimates are probably over-optimistic. The missile undoubtedly cannot attain maximum range when traveling entirely at maximum speed, so there is a trade-off there. The best cruising altitude also may not be usable because it makes the missile too vulnerable. All that said, the substitute engines do have better specifications than the "original". It should also be noted that even the original engine had a second, superior set of specifications for operation at "military power". Normally such engines can be operated at 110% of rated thrust. It is not recommended to do that for "long periods" and a complete inspection/overhaul is required after each such use. Since the missile isn't coming back, the latter is not an issue :-). The question would be how reliable is the engine at this power setting and for how long.

[Goose]

Some more information on Ukraine's new cruise missile. They are using a lot of "off the shelf" tech- turbofan engines from L-39 jet trainers, and warheads from Soviet FAB gravity bombs.

Commentary online suggests this could allow a large number to be built from existing stock quickly, but that further production of the engines could then be a limiting factor once the readily available supply dries up. There are many thousands of those L-39 jets in service (~10k),

Not so sure about that number. https://en.wikipedia.org/wiki/Aero_L-39_Albatros says 2,900 (total) were built. Ukraine operated a number of them, but nowhere near even 1,000 of them

but production of new turbofan engines will be tough to hit their 3,000 per year goal.

Possibly. However if they don't use the Ivchenko AI-25TL but rather its contemporary substitutes e.g. Garrett TFE731 (https://www.code1aviation.com/731) or the Williams FJ44-4M they may be able to simply buy them in the required quantity.

Also suggestions that the range (3000km) and speed (850-900 km/h) estimates originally shared are perhaps ambitious with this engine though of course it is possible the engine has been modified from it's typical commercial version.

https://x.com/John_A_Ridge/status/1958636077792592213
https://x.com/John_A_Ridge/status/1958562813699309817

IMO both the range and speed estimates are probably over-optimistic. The missile undoubtedly cannot attain maximum range when traveling entirely at maximum speed, so there is a trade-off there. The best cruising altitude also may not be usable because it makes the missile too vulnerable. All that said, the substitute engines do have better specifications than the "original". It should also be noted that even the original engine had a second, superior set of specifications for operation at "military power". Normally such engines can be operated at 110% of rated thrust. It is not recommended to do that for "long periods" and a complete inspection/overhaul is required after each such use. Since the missile isn't coming back, the latter is not an issue :-). The question would be how reliable is the engine at this power setting and for how long.