Let's look over some statements of speed from the Hyper Agent Gridman book (which came with the SSSS.Gridman book). The Ultraman wiki pages for Gridman, God Zenon and Dyna Dragon list the speeds and masses too, but let's get it directly from the source.
Thunder Jet has a mass of 47,000 tons (47,000,000kg) and a maximum flight speed of mach 5.
(Rough translation of the relevant text)
T = 340.29 X 5
= 1701.45m/s
KE = (0.5) X mv^2
= (0.5) X 47,000,000 X 1701.45^2
= 6.80309044e13 joules
= 16.25977638623327 kilotons
With that out of the way, we just need to do it again for the rest of them! Dyna Fighter has a mass of 96,000 tons (96,000,000kg) and a maximum flight speed of mach 36. On this very same page, King Jet has a mass of 144,000 tons (144,000,000kg) and a maximum flight speed of mach 18.
(Rough translations of the relevant text)
= 12250.44m/s
KE = (0.5)mv^2
= (0.5) X 96,000,000 X 12250.44^2
= 7.20351745e15 joules
= 1.721681990917782068 megatons
T = 340.29 X 18
= 6125.22m/s
KE = (0.5)mv^2
= (0.5) X 144,000,000 X 6125.22^2
= 2.70131904e15 joules
= 645.6307456978967139 kilotons
Dragon Fortress has a mass of 240,000 tons (240,000,000kg) and a maximum flight speed of mach 43.
(Rough translations of the relevant text)
= 14632.47m/s
KE = (0.5)mv^2
= (0.5) X 240,000,000 X 14632.47^2
= 2.56931014e16 joules
= 6.1407986137667300852 megatons
King Gridman has a mass of 204,000 tons (204,000,000kg) and a maximum flight speed of mach 50.
(Rough translation of the relevant text)
T = 340.29 X 50
= 17014.5m/s
KE = (0.5)mv^2
= (0.5) X 204,000,000 X 17014.5^2
= 2.95283074e16 joules
= 7.0574348470363288399 megatons
Final Results
Thunder Jet's maximum flight speed = Mach 5
Thunder Jet's kinetic energy = 16.26 kilotons
Dyna Fighter's maximum flight speed = Mach 36
Dyna Fighter's kinetic energy = 1.722 megatons
King Jet's maximum flight speed = Mach 18
King Jet's kinetic energy = 645.631 kilotons
Dragon Fortress's maximum flight speed = Mach 43
Dragon Fortress's kinetic energy = 6.141 megatons
King Gridman's maximum flight speed = Mach 50
King Gridman's kinetic energy = 7.057 megatons
Thunder Jet has a mass of 47,000 tons (47,000,000kg) and a maximum flight speed of mach 5.
From these official figures, we can also find the kinetic energy. We'll need the speed in m/s.
T = 340.29 X 5
= 1701.45m/s
KE = (0.5) X mv^2
= (0.5) X 47,000,000 X 1701.45^2
= 6.80309044e13 joules
= 16.25977638623327 kilotons
With that out of the way, we just need to do it again for the rest of them! Dyna Fighter has a mass of 96,000 tons (96,000,000kg) and a maximum flight speed of mach 36. On this very same page, King Jet has a mass of 144,000 tons (144,000,000kg) and a maximum flight speed of mach 18.
T = 340.29 X 36
= 12250.44m/s
KE = (0.5)mv^2
= (0.5) X 96,000,000 X 12250.44^2
= 7.20351745e15 joules
= 1.721681990917782068 megatons
T = 340.29 X 18
= 6125.22m/s
KE = (0.5)mv^2
= (0.5) X 144,000,000 X 6125.22^2
= 2.70131904e15 joules
= 645.6307456978967139 kilotons
Dragon Fortress has a mass of 240,000 tons (240,000,000kg) and a maximum flight speed of mach 43.
T = 340.29 X 43
= 14632.47m/s
KE = (0.5)mv^2
= (0.5) X 240,000,000 X 14632.47^2
= 2.56931014e16 joules
= 6.1407986137667300852 megatons
King Gridman has a mass of 204,000 tons (204,000,000kg) and a maximum flight speed of mach 50.
T = 340.29 X 50
= 17014.5m/s
KE = (0.5)mv^2
= (0.5) X 204,000,000 X 17014.5^2
= 2.95283074e16 joules
= 7.0574348470363288399 megatons
Final Results
Thunder Jet's maximum flight speed = Mach 5
Thunder Jet's kinetic energy = 16.26 kilotons
Dyna Fighter's maximum flight speed = Mach 36
Dyna Fighter's kinetic energy = 1.722 megatons
King Jet's maximum flight speed = Mach 18
King Jet's kinetic energy = 645.631 kilotons
Dragon Fortress's maximum flight speed = Mach 43
Dragon Fortress's kinetic energy = 6.141 megatons
King Gridman's maximum flight speed = Mach 50
King Gridman's kinetic energy = 7.057 megatons