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Larry wrote: > > I fly window open all the time with my Bubble Coupe. I > can't give you the why's and wherefore's, but I > do know that the bubble is more aerodynamic than the > flat shield. I'm actually more inclined to bring > the passenger side window up and over center, thus > giving me open windows on both sides, but a sun > shield overhead. I also figure that this overhead > config. gives better lift on takeoff than both > windows down. As far as my reasoning for the > aerodynamics of the bubble, take a look at all racing > farings on motorcycles. They're all bubble style. > No flat shields out there. The flat shield pushes > through the air causing much turbulence behind it. > The bubble lifts the air and contours it up over and > back down behind the canopy. No turbulence, and increased lift. > > Larry You do a great job of describing the air flow over a bubble windshield, Larry. Those are the advantages of the bubble type along with, I was told, a _slight_ decrease in internal noise (that I've never seen documented). The flat windshield does give a more turbulent airflow and less lift, I would guess. It's one advantage (other than appearance aesthetics) is that the airflow/slipstream does NOT follow the top of the canopy closely. The advantage of this is an unmeasured reduction in the tendency to suck hats and headsets off a tall pilot's head. Also, flat windshields may crack more and require more replacements. Anyone know which is cheaper/easier to replace? I've long had the practice of closing the windows from just before the take-off roll to about 500-1000 feet high on climb out to increase the lift and reduce drag. Your method of pulling the passenger's window the top center may give most of the lift advantages while keeping better cooling -- I'll try it. In summary: ain't much difference. If you like the appearance of flat, keep it. If you like bubble, consider the conversion. If you go to the Alon type instrument panel which REQUIRES the bubble windshield, that settles the issue for you. The aerodynamic differences are probably measurable, but you'd have to have a pretty sophisticated measurment program to quantify. I'm expressing a lot of unsubstantiated opinion here -- please don't take this as gospel. Ed > Ed Burkhead wrote: > > > ----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- > > Here's one other thought about the bubble vs. the flat windshield: With > > my flat windshield, as I fly with my windows open, I can push my fingers > > up about 4-5 inches above the window-line before feeling the slipstream. > > I think the flat windshield "flings" the air upward. > > > > Speculation: The curve of the bubble may let (or make) the slipstream > > conform more tightly to the line where the windows would be. > > > > I'm thinking the flat windshield may give a bit more buffer from the > > slipstream when flying windows-open. > > > > Now I've never owned a bubble windshield plane. Could those with access > > to both try sticking their fingers up to see if there's a difference or > > give some judgment of wind flow inside the cockpit when flying windows > > open? I'm curious. > > > > Curious Ed > > > > __________________________________________________ > > To unsubscribe from this list please send mailto:[EMAIL PROTECTED] > > ___________________________________________________________ > > T O P I C A The Email You Want. http://www.topica.com/t/16 > > Newsletters, Tips and Discussions on Your Favorite Topics __________________________________________________ To unsubscribe from this list please send mailto:[EMAIL PROTECTED] ___________________________________________________________ T O P I C A The Email You Want. http://www.topica.com/t/16 Newsletters, Tips and Discussions on Your Favorite Topics
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