Technical Discussions

[Dave Jackson]

It appears that there is no arena on the net, which is devoted to technical discussions about helicopters. This might be due to a limited interest in the subject and that many would-be developers are secretive about their ideas. Personally, I would rather broadcast an idea and have someone destroy in a few minutes, then work on it for a many months only to arrive at the same conclusion.

PPRuNe is an excellent candidate for this type of forum because it arraigns its subject matter in a hierarchical manner. People would be able to discuss the technical aspects of helicopters (and proposed helicopters) in a separate forum or thread, without offending the users of these craft.

The following is posted for (can't think of a reason) :)

___________________

Definition of [Power Loading] as applied to a helicopter:

R.W. Prouty [Even More Helicopter Aerodynamics] Glossary;- "Power Loading ~
The ratio of gross weight to the horsepower rating of the engine."

J. Gordon Leishman [Principles of Helicopter Aerodynamics]:- "Power loading
is the ratio of the thrust produced to the power required to hover."


Can anyone clarify this apparent discrepancy?

[Nick Lappos]

Dave,
The definition that Leishman uses is much closer to that which we use at Sikorsky. The thrust is the weight, and we use the weight divided by the horsepower to hover, so we agree with Leishman.

Prouty's engine rating would yield different values for aerodynamically identical aircraft with different ratings on the engine, which would erode the usefullness of the ratio.

[chips_with_everything]

Dave and fellow prunes,

I would encourage use of PPRUNE Rotorheads for technical discussion about helicopters, rather than establish anything else.

1) Technical issues should be of interest to users/drivers.
2) The proper way to avoiding offense is to avoid being offensive. Accurate and truthful- yes, emotional and personal- no. Writers should imagine they are facing the person(s) addressed, and readers should don elephant hide.

Let's look forward to more successes like the one about 18 degree offset. Good one PPRUNE and PPRUNERs, thanks to Nick, Lu, Frank and many others we are now better informed for sure, and possibly better pilots too.