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

I'm considering this for my stainless exhaust shroud (pictures soon), but I'm concerned about focusing all the heat in one place - onto my wood prop.

 

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

Exhaust augmentation may work as a variable geometry scoop. But...

Why not just vary the geometry directly?

A moveable floor for a NACA is easy light and effective.

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

If I understand NACA theory correctly (unlikely) the problem is with "back pressure", not with the duct.

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

Nathan,

 

I would like a copy if you don't mind. I tried to PM you about it but it said your mail box was full . Here is my email address: admin@homebuiltairplanes.com . Thanks.

 

Jake

Here is a tip for placing peel and stick decals. Peel the decal and spray the sticky side with some Windex. Put a little Windex on the location you intend to put the decal. Apply the decal. The Windex will allow the decal to slide around until you have it just where you want it. Take a rag and apply pressure outwardly on the decal to get the excess liquid out from under the decal and remove any wrinkles and bubbles. Let it dry. Works Great.

 

Jake

Oh, btw, is there a spell check on this site....poor spellers/typest want to know.

From rotten speller to another >> Te easiest way to spell check is to copy and paste the text into a word document and spell check there.

 

Jake

If you know of a "Turbocharged wonder motor from Japan." please do tell us were you got it. I would love to put one in my Cozy.

Yeah, it's the Mazda rotary. Three moving parts and tough as nails. Won't make fuel though!

 

I definitely think the gypsum would be WAY too heavy. If it would work with like a light weight speaker box carpet glued over it or a much lighter radiating materiel than I would be interested. I've got a LONG way to go before I need to worry about it though. Maybe you could do some tests for us?

 

Jake

TES111,

 

Do you know what the weight of this stuff is? How thick is it? I wonder how hot it would heat the surface it is laying against. I would hate to melt the bottom out of my aircraft at 10,000 feet (or 20 feet for that matter) . Since it's free, I sent for a sample of the material. Should be here in a couple of weeks. Seems like it might be simpler than ducting air. If only it could cool as well.

 

Jake

You'll learn all you need about VFR nav in marginal weather using a infantry terrain map while doing 120 at 10' agl under NVD.

:D

 

Ok, I could use some help with JAAT, AHIP, and "Air ro Air at Hunter Liggett - 58's 10 all other A/C 0". Other than that I think I got what you were saying . Thanks for the insights.

 

I've considered several times going the W/O rotorjock route, but I'm pushing the age bracket and I'm just a hair too tall

I'm pushing the age bracket myself. I'll be 29 in January which is the cut off. How much is a hair? I'm sure you could slump down just a bit right? They are hurting for pilots so they may also give a medical waiver for your height. I've got my flight physical on June 4th, would you like me to ask the doc about it?

 

Jake

Right - like a garmin handheld.

Oh..so you want an affordable, easy to use, reliable moving map that works right out of the box for what you need. How boring .

 

Blackhawk sounds cool, but then I've always liked wings that stay put.

Unfortunately due to some poor educational and career choices I've missed the boat for a direct shot to the fast movers. Had I continued on to college right out of High School instead of waiting till now, I would have had decent chance at them. Dummy me felt that going into the Army straight out of school was the smart thing to do. I enjoyed myself but I could have done much more. If I knew then what I know now....

 

But...I've got a little back door plan going . The Army sends a certain number of rotary wing pilots to the Naval Test Pilot School each year. Before attending, the rotary pilots go to the Army fixed wing course. During the Naval Test Pilot School students get high performance jet time including F-18s. Also, if I can finish a degree in one of the hard sciences, I can apply for the Astronaut program as well. They just picked up 4 Army Warrant Officers for the NASA program this year so it's not unheard of. So, even though the going may be tough, there are still some options open to me.

 

How long were you in the RAF John?

 

Jake

What AC type are you hoping for?

I'm actually hoping for Black Hawk. It's not the most glamorous helicopter out there but it has the most mission variety. Apaches are interesting but some of the Apache pilots I have talked to hate them and tell me that the flying is very boring and predictable. It really depends on how well I do in school. From what I'm told, the top 20% pretty much have a choice of which direction they go. This may or may not be true so I'll just have to wait and see.

 

So Linux is the OS that you would go for? Shouldn't be too difficult if you can find some Linux compatible moving map software. I've seen a couple but don't know how good they are. Linux should load on the tablet no problem as well. I've seen at least one tablet that comes with Linux pre-loaded.

 

Anyway, for me the real fun would be interfacing the tablet with the aircraft. I would have to either seriously pick the brain of someone who has done this before or find an off the shelf solution (preferred).

 

Jake

If I remember correctly, you haven't done a lot of flying yet.

 

Ouch..that hurts John, that really really hurts . Just because I have no real practical experience and I like to run my mouth should be no reason to bring out the big guns!

 

Seriously though, I see what your saying and I won't really know until I've experienced it for myself. It's easy to say how I will keep a 2nd source or navigation inputs at the ready at all times but it's human nature to begin to rely on the easiest source. Complacency and Murphy have a nasty tendency to get together to bite us on our butts at the most inopportune time.

 

I will still maintain my postion that a Billy G XP system would see me through. Bill wouldn't let me down when I really need him.

 

Hopefully by this time next year I will be a fully qualified pilot just starting the combat skills phase of Army flight school. Then I will really be a know it all with no real practical experience!!!

 

Jake

I wouldn't feel too bad about a windows system in my aircraft. Hopefully I wouldn't be relying on my moving map to the extent that a blue screen would make me buy the farm. Having spent most of my learning curve with 95 and 98, XP seems rock solid. But, then again, I haven’t spent too much time with Linux although I have managed to crash it as well.

 

I think that with a fresh xp install and only a few programs installed, the risk of frequent blue screens would be minimal. I put my home system through 10 times the abuse and I rarely lock anything up. Maybe I could do a dual boot system with identical OS installations. If one goes down I could boot the next drive and keep on going .

 

Ok, I'm ready to dodge the rotten tomatoes!!

 

Jake