Tyler said:

You've really come a long way from your first pulsjet engine. But while your engines have improved and become more powerful, your videos have become more scary! 

Honestly, couldn't you find a smaller propane tank? 

Be safe and good luck with your next iteration. Smaller tank, stronger weld, and some steel-toe shoes with a helmet!

Thank you tyler, i had a 5kg propane tank but i was in a confusion whether 5kg gives enough pressure for my engine.

Tyler said:

I've always been under the impression that propane is a constant pressure gas – meaning that a full 5 gallon tank gives you approximately the same pressure as an almost empty 5 gallon tank. Therefore a small camp-stove sized cylinder should also give you the same pressure. Someone please correct me if I'm totally off base here.

The only thing I've seen that can really effect pressure is outside temperature – which should be an issue in India, but can be an issue in the cold Northwest where I live. 

you are correct but if you run the engine for a long time pressure decreases inside the cylinder, large capacity cylinders can withstand the high fuel flow than smaller one. And just make a try to start a 40pounds thrust engine with 5 or 2kg gas cylinder. Iam 100% sure it wont start.