AVX is upping the communication on their efforts to modernize the OH-58. One of their biggest selling points is the ability to hover out of ground effect and the virtual elimination of brownouts when landing. The info below is from their website.
Hope they get a chance to prove their claims, it is a nice piece of helicopter evolution. I personally doubt that they will fulfill all their claims, and suspect that there are a few drawbacks, but still it is a small risk for a great improvement. IMHO / RAF
First of all, I'm an airplane engineer, not a helicopter specialist, so I migth be out of line but here is a few things needs to be solved/proved. The claim that same power will give 11% more lift and 30% more useful load. My guess is that this is verified in a CFD model or wind tunnel and might be true, given that the transmission have the same weight, but I believe that the coaxial rotor will be heavier. And every extra pound goes off the payload. Vibrations is very tricky to deal with when you have coaxial propeller, might be the same in a helo, don't know. Not an expert on helo tactics, but should not the sensors be better positioned above the rotor disk? And as always, the problem easiset to foresee is the unforeseen... But as you say, it looks great and I hope they get a chance to prove me wrong.
Everything you said sounds valid to my untrained ears. And I totally agree about the sensor positioning. It seems that they've forgotten about the utility of masking a helicopter and exposing only the sensor dome for ISR tasks. I wonder if the rotor system prevents them from doing that?
Hope they get a chance to prove their claims, it is a nice piece of helicopter evolution. I personally doubt that they will fulfill all their claims, and suspect that there are a few drawbacks, but still it is a small risk for a great improvement.
ReplyDeleteIMHO / RAF
What drawbacks do you foresee? It looks great to me.
ReplyDeleteFirst of all, I'm an airplane engineer, not a helicopter specialist, so I migth be out of line but here is a few things needs to be solved/proved.
ReplyDeleteThe claim that same power will give 11% more lift and 30% more useful load. My guess is that this is verified in a CFD model or wind tunnel and might be true, given that the transmission have the same weight, but I believe that the coaxial rotor will be heavier. And every extra pound goes off the payload.
Vibrations is very tricky to deal with when you have coaxial propeller, might be the same in a helo, don't know.
Not an expert on helo tactics, but should not the sensors be better positioned above the rotor disk?
And as always, the problem easiset to foresee is the unforeseen...
But as you say, it looks great and I hope they get a chance to prove me wrong.
Best Regards /RAF
Everything you said sounds valid to my untrained ears. And I totally agree about the sensor positioning. It seems that they've forgotten about the utility of masking a helicopter and exposing only the sensor dome for ISR tasks. I wonder if the rotor system prevents them from doing that?
ReplyDeleteAnyway thanks for stopping by and sharing wisdom.
Almost seems like the evolution of the autogiro...
ReplyDelete