Can I change the bend angle?

[rockooby]

Hello everyone,

I am trying to make Bruce Simpson's 55lb Lockwood pulsejet design (full size this time.) I started by ordering parts, and instead of making my own 180 degree bend I decided to buy two 90 degree mandrel bends. When I got my 90 degree bends in the mail today I noticed that two bends conjoined radius was much shorter than the ones called for in the design. I was wondering if instead of replacing my 90 degree bends if I could just calculate the difference in length between my bends and the ones called for in the design and add a straight section to make up the difference? 






Thanks!

[racket]

The large radius bend would have smoother flow than the short radius bends you have , they may create "problems" even with the straight section added between them , you could try using what you have , but if it doesn't want to run then you can always replace them with the larger radius unit .

Short radius bends between a sore thumb combustor and the turbine scroll inlet on our engines suffer from poor flow in the bend .

Cheers
John