JakeC

Hey Marbleturtle, Someone posed a similar question on my site the other day about the effectiveness of full flying control surfaces and why they usually need to be designed larger than a stabilizer with a hinged flap type control surface to produce the same effect. Here is the link: http://www.homebuiltairplanes.com/forums/showthread.php?s=&threadid=614 The response he received is probably applicable to your question as well. Jake

As far as the search engine thing goes. One of the characteristics of this and most brands of discussion forums is that they do not let the search engine "spiders" read the content. It has to do with the fact that the site is actually written in PHP instead of HTML. There is a modification that can be done to this brand of discussion forum that will allow the search engines to index the content, however it's a little risky in my opinion. I'm considering doing it to my site but I'm a little chicken. The best way for this site to improve it's ranking in the search engines is to get as many links to it as possible on sites that have to do with homebuilding aircraft. When the spiders go out and look for sites, they assign a higher ranking to sites that have a large number of sites linking to it. Also, you can register the site with search engines to let them know you exist. Jake

Hopefully with your configuration, if it really works as an exhaust augmentor like you hope, there should be a good amount of mixing between the exhaust gases and the air from your cooling system before it hits the prop. If not, I guess you would end up with a pretty cool racing stripe on your prop (Char Marks). Jake

I was really thinking about the variable geometry inlet phenomenon that may occur as a side benefit of using the augmentor with an NACA scoop and not a reason to use the augmentor. Besides, you can mechanically vary the inlet area all you want but if the pressure is too great to allow the air in, you probably won't get any benefit from it. Jake

This is my understanding as well. It kind of makes sense considering how easy any back pressure would allow the air stream to slip right past the inward bend and continue to follow the contour of the fuselage. I suspect that the vortex generators give the air stream better adhesion to he inward curve and make it more affective at counteracting the back pressure. The method that seems to me to have the best shot at solving the problem is the one that John is experimenting with; a combination of Vortex Generators and exhaust augmentation. The exhaust augmentation SHOULD create a negative pressure within the cooling ducting effectively lowering the pressure at the scoop. In my "concept" of things, a scoop with only vortex generators and a scoop with both the generators and augmentation should loose it's effectiveness at the same back pressure level. However, the scoop with both should be moving a greater volume of air before this critical pressure threshold is reached because it is starting out with a lower pressure because of the suction effect of the augmentor. Here is where it gets even more interesting for me. Assuming what I just wrote above is correct, it would seem to me that a NACA scoop that uses an exhaust augmentor system to suck air through the system may act as a variable geometry scoop of sorts. When the throttle is firewalled the augmentor is sucking the greatest amount of air into the inlet. As the throttle is reduced, the pressure at the inlet is increased and the inlet begins to lose its effectiveness. When this happens, the air that cannot make it into the scoop just slides across the bubble of compressed air as if it's a continuation of the fuselage and continues on its way. Thus the area of the inlet is effectivly reduced. Since you don't need as much cooling air when throttled back at cruise as you do when climbing out on take off, the fact that this system would lose some of it's effectiveness at cruise may prove to lower the drag at cruise as well. Now, this is all highly theoretical but I would like to hear your comments on this. Jake

Hey folks, Just wondering if there are any builders down here in the Dothan, Enterprise, Ozark, Ft. Rucker, Elba area of Alabama? I just moved into my wonderful 4 bedroom Army issue Duplex here on Ft. Rucker and would love to meet with any Cozy builders, fliers, or wannabe’s in the area. About 100 miles from Ft. Rucker is my practical travel limit due to a 99-mile limit the Army has imposed on me without a pass. It's kind of a hassle with those types of restrictions but, with over 1000 newly minted Warrant Officers in various stages of flight school, I guess they need to keep control somehow. I ran into the local EAA chapter president the other day at the airport and he mentioned that there is one flying Cozy in the chapter. I'm hoping he will be at the next meeting. Take care. Jake

Sure does. Thanks for the pic. Jake

One other thing to consider is, with silver, you would have to have one perfect surface in order for it to look good. I was thinking about the same thing but with the moldless construction I'm not sure I could get it that perfect. What do you think? Jake

Here is the other photo:

Here are a couple of pictures I took at Arlington this year that give good views of the wing pods on Ken and Carol Murphy's Cozy. Although I don't know the actual volume, I'm willing to bet they are about the same volume as medium sized duffle bags. Anyone know the acutal volume? I wasn't able to speak with the owner because each time I came around he was either talking with someone else or not present but I did talk with Jim White (thanks Jim) and he mentioned there is very little drag penalty. It is his understanding (correct me if I'm wrong Jim or Ken) that the speed loss is only around 1-2 knots. Not bad at all! Jake P.S. It didn't even register at the time that I was looking at the Cozy prototype! I take it Nat sold his and built another?

On your site you mention that the CG of your engine is at 20.7 inches from the firewall. Where is the CG of the 13b, is it pretty much in the middle of the engine. I imagine with the PSRU it is somewhere aft of the middle. Were your calculations of the CG of the engine with all of the accessories and plumbing or just bare engine. Thanks in advance. Jake

Thanks John, I don't know how I missed it. Jake

John, I was wondering if you had these dimensions off the top of your head: Firewall to back of engine Length of engine w / PSRU attached Not in a big hurry, just trying to get my mind around things. Thanks. Jake

I second that idea. I would actually like this feature on my board as well. John or Nick, if you come up with a way to do this let me know please. Thanks for this great site by the way! Jake

This is something I was just going to ask but you beat me to it. What days are you planning on attending? Jake