Originally Posted by eatond
I agree with Barry and think you right on with the duct shape. It's looking very good.
Hey, after taking a close look at the drawings I got a dumb question. How are you getting those batteries in and out? Removable nose?
Thanks Dan and Barry. I am glad to see I am not the only one thinking along these lines. But like I said, even if I am wrong, the only thing lost is a little bit of time. But we gain the knowledge of how to make ducts better and more efficient. My only wish is that I had the time and resources to actually test both theories.
As far as the batteries. The battery compartment has an opening where the canopy is. Its just not apparent because I have not cut those bulkheads off yet. On my other F22, I made the canopy out of foam and it was removable. I am thinking I will do something similar as it was very easy to make the other one that way. But I am unsure what I am going to do around the canopy area at the moment.
Ron, I totally agree with you. I was thinking the same thing. In fact I have been racking my brain thinking about that for weeks. The problem is that if you put something like a nosecone in the intake, you are imparting more wall turbulence because now there are two surfaces the air must travel along. And then a third or fourth wall just to support the nosecone. I am sure though, that your thinking would most likely result in a more effecient, less blunt intake. The question is if the gain is worth the loss.
My other thought about the straightline of the intakes. With the geometry of the intake versus exhaust of the F22. Some part of the ducting must deviate from a straight line. In my opinion it is better to have the intake curved than the exhaust. For starters the exhaust is where your going to want the greatest efficiency, since the only thing you can do after the fan is lose. Also, the curve of the intakes may end up a mute point once the plane is actually in the air, and air is being force into it. Now I am sure if the intake were to make a couple of 90 degree turns, that would be bad. But the little bit of offset I am dealing with should not impose a huge loss. At least less of a loss than if I were to use the same amount of offest on the exhaust.
Oh, btw Ron, thanks for your kind CAD words. This is the first thing I have ever done in 3D in ACAD. I have been a long time CAD user at work with 2D drawings.