http://www.youtube.com/watch?v=yY1idP3QF6Y
It's Sean D Tucker in his Challenger III Biplane.
This aircraft has a unique cowling on it so I thought I would talk about what I think is going on here and why it works so well for him.
First of all his engine is heavily modified and produces over 400hp.
Plus as you watch the video you can see that he spends some time hanging off the prop on full power at high angles of attack.
Let's look at some photos and comment on each one.
Firstly the front.
As you can see the inlet is not in the usual place.
As he spends most of his time in a high angle of attack then he needs to make the best use of the high pressure air that is forms underneath the cowl.
If the inlets were on the side as usual they would be masked off by the lower cowl from that air.
I'm a little surprised at the prop choice - as it is not providing any high pressure pulses of air to that inlet. At the props root ends you can see it is more of a plain shaft than an airfoil.
There are props that exist that have the airfoil all the way in to the spinner. That type of prop would aid cooling when the plane is in the condition of slow forward speed and on a high power setting.
Also note the inlet size - remembering 400+ hp.
Onto the sides.
He's taking full advantage of the low pressure area here on the sides of the cowl to exit some air.
Onto the lower cowl.
A smaller than usual exit here and it is well back on the cowl - it does have a big lip on it though which helps to make a lower pressure area behind it helping to suck the air out.
Finally the top.
2 more small exits at the top of the cowl just in front of the wing.
As you can see there is a lot of exit volume compared to the inlet volume.
I plan to do a similar thing on the Twister with regards to the side exits, taking advantage of the existing tapering shape of the fuselage sides. I will also have a lower exit which I can easily change the size of should the 'Mark I' version not be correct.
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