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Old 02-27-2018, 07:45 AM
  #3758  
SALMONBUG
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Originally Posted by Woketman View Post
The shape of the intake can indeed have a huge effect... when there is ducting. But in the case of an R-54, the engine is out in the open air! THERE IS NO CONSTRICTING DUCTING! The engine is able to breath with no significant constrictions, therefore there is no difference, it is out in the open with no intake issues. Dean was absolutely correct, beyond doubt.
Some last words on the subject

Let's talk about the r54 configuration and particulary about the boat tail end and the compressor.
let your imagination work a bit and imagine a jetcat p60 or any kind of similar engine on a testand with . a dozen of sensor monitoring and recording all the possible data about it . Now imagine a volunteer holding a nice R54 boat tail in his hands and slowly approaching it from the compressor runing at max Rpm. the engine parameters will vary for sure..........
Quantify and determine the variation and the reason of it is complex.
If I had to predict what will hapen I would say ( but without any certitude) that either the engine receive enough airflow,it will be affected by the fact that the angle off the air attacking the compressor blades will vary and then reduce the compression ratio .

The first example that come in my head about people who have been disurbed and had to solve that complex problem is when lockheed and douglas went in competition to build a 3 engine long haul airplane.
lockheed decided to place the engine in the back of the fuse and build a long curved air intake going from top of the fuse to the engine. that was the lockheed tristar
douglas decided to go with a apparently more difficult challenge and place the engine on top of the fuse ( requiring to design a complex strong vertical fin). The dc10

lockheed losted the competition simply because they encounterd unexpected enormous problem with the design of the intake and also because in flight at high body angle, the fuselage was maslking the intake and the plane came on the market a bit too late

Last edited by SALMONBUG; 02-27-2018 at 08:10 AM.
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