Testing of the STOVL (vertical takeoff and landing) version of the new F-35 recently showed that its F135 engine, the most powerful to ever be used in a fighter, demonstrated its ability to provide more power (41,100 pounds of thrust) than was basically required (40,550 pounds). Tests three years earlier revealed that the heat from the F-35Bs engines will damage the aluminum matting used for rapidly constructed airfields. The F-35B engine heat won't damage the decks of current aircraft carriers, but the aluminum matting is toast, so to speak, and will have to be replaced with sturdier stuff.
The F-35B is larger, and puts out more engine blast, than the current STOVL aircraft, the AV-8 Harrier. The AV-8 first entered service in 1969. That early version was used mainly by the British Royal Navy and the U.S. Marine Corps. It was a 11 ton aircraft (7 tons when taking off vertically) that carried about two tons of weapons. In the 1980s, a more powerful 14 ton version was developed, which could carry three tons of weapons.
The F-35B, which will replace the Harrier, is a 27 ton aircraft that can carry six tons of weapons and is stealthy. In vertical takeoff mode, the F-35B will carry about twice the weapons as the Harrier, and have about twice the range (800 kilometers).
There's one Harrier trait the F-35B hopes to avoid. The Harrier has the highest accident rate of any jet fighter. This is largely because of its vertical flight capabilities, which give it an accident rate similar to that of helicopters. The U.S. Marine Corps has lost a third of its 397 Harriers to such accidents in 32 years. In the last twenty years, India has lost half of its 30 Harrier vertical takeoff fighters to accidents. Other users have had similar experiences. It remains to be seen how much less accident prone the F-35B will be.