Posts: 243
Joined: 2/3/2002 From: Cleveland, OH, USA Status: offline
I have mine just about ready to cover. The engine will be a Saito 180 FS mounted as a sidewinder. I built mine as a taildragger with a built up wing.
How did your plane knife edge? I will be using slightly longer and taller canopy, and the canopy will be set a bit further forward than stock. They'll be plenty of power but I wonder if I'll have enough side area to the fuselage.
Posts: 243
Joined: 2/3/2002 From: Cleveland, OH, USA Status: offline
The article was published in the November, 1984 issue of Model Airplane News. If you like, I can email you a copy of the article.
This is a scratch built project. Balsa fuselage and tail w/ foam wings ( I drew a built up wing for mine.)
73" WS
10.5 - 11 lbs all up weight.
1005 sq. in WA
.91 2 stroke ( mine will have a Saito 180 mounted sideways- gives a MUCH better look to the nose and helps get the centerline of the carb on the centerline of the tank, something all stock Kaos's have a problem with.
Mine is ready to cover, but I am too lazy to get started.
Posts: 107
Joined: 5/6/2003 From: SAN ANTONIO,
TX, USA Status: offline
I'm the one who published the article in M.A.N. in 1984. Been a long time, but I remember it flying really stable. It was a bit "draggy" with the thick airfoil and all, but we were also working with the available power from an O.S. 90 in that day. Would probably be great with one of the newer 1.08 2S or a big 4S like you are talking about. If I had it to do over, I might consider thining the airfoil and fuse width slightly to reduce drag. I was also, at that time trying to stay true to the original design. Good luck and hope you enjoy it.
Posts: 243
Joined: 2/3/2002 From: Cleveland, OH, USA Status: offline
Good to meet you, Dewey. My wing will be just a little thinner than yours. I think the original Kaos had a 19% root and a 17% tip- I made mine a constant 18%.
I put dual servos in the tail for the elevators and made it a taildragger . I ended up having to extend the nose moment about 2 inches to bring the C.G. to center on the spar. The Saito 180 is light for it size- if I had used a YS 140 I think it would have been right on the money as it was.
Posts: 243
Joined: 2/3/2002 From: Cleveland, OH, USA Status: offline
The Kaos Gods were in a good mood today. I was actually able to get the thing off the ground 3 times and still keep it in 1 piece.
1) First flight needed 3 clicks left aileron trim ( suspect lateral balance a bit off- will add about 1/2 oz. to left wing tip.) All other trims perfect.
2) The C.G. (dry) was set about 1/8" behind the root rib's spar center. This is about 3/8" forward of recommended C.G. Knife edge flight required about 75% rudder deflection to hold at full throttle. I will start sneaking the C.G. back toward the recommended point.
3) Takeoff required about 30 % power and took about 60-70 feet into the wind. All landings were made faster than need for safety, but no bad habits expected at slower speeds. I set the gear outboard by one rib bay from prototype. Ground handling was rock solid with no tendency for the plane to nose over, even at full power on takeoff.
4) Tracking and general handling very good, with unlimited vertical. The engine peaked at 9150 RPM, and I backed off to about 8800 to fly. Most flying was done at half throttle. Saito's go very rich in the mid range, so I only got about 9 minutes flying- this will probably go to 11 - 12 minutes after the engine is fully run in and I can lean everything out.
5) The plane flies just like the smaller Kaos planes, but smoother and with instant acceleration when you hit the power. I may try a 17 x 10 APC once I get the plane all trimmed out. I think it needs just a bit more top speed, and there is plenty of vertical to spare. The fuel tank is right behind the firewall at the moment. It will be easy to relocate over the C.G. and add a Cline regulator.
6) The light colored area at the wing root is some masking tape and 1/32" ply I was using to protect the wing while ballancing.
< Message edited by MarkD -- 9/29/2003 1:15:40 AM >
That does it! I can't live without a Kaos. My near worn out Bridi Killer Chaos deserves an honorable discharge, bbut it's spirit should live on if I build another from the plans, maybe a turtle deck up there, new canopy and perhaps my old 91 Surpass can find a decent home :-)
Posts: 50
Joined: 7/22/2002 From: Springfield,
MO, USA Status: online
I just finished building the K-90 from your plans. I feel that it came out a little heavy at 11 pounds, with 14 oz of nose weight, so I am putting a few lightening holes in the fuse sides and rudder, moving the radio gear as far forward as possible, as well as the battery, hoping I can remove some of the lead. I built the wing from balsa instead of foam. It has a new Super Tiger 90 for power. I am a little leary of putting too many holes in the side of the fuse, because of the large tail surfaces. What are your thoughts?
Posts: 243
Joined: 2/3/2002 From: Cleveland, OH, USA Status: offline
The aft fuselage is extremely strong if you used the material call outs as I drew it. Most of the load in any fuselage is in the corners, not in the center of the sides or top and bottom. You could add fairly large lightening holes. However, you won't get nearly enough lightening to correct the CG. You will have to relocate equipment.
For the following, I'll assume you located all the formers and firewall in the locations I specified. If you can, please give me the following:
1) type and weight of the servos you used. 2) distance to the center of the aft servo array from the front face of the aft wing bay former (side nearest wing opening) 3) distance from the front face of the firewall to the center of your engine's glow plug. 4) weight of the battery and both its original and proposed cneter locations measured with respect to the front face of the aft wing bay former. 5) proposed centerline location of the servos' new location as measured with respect to the front face of the aft wing bay former. 6) location of the center of the lead weight you added measured with respect to the front face of the aft wing bay former.
I want the measurements with respect to the front face of the aft wing bay former because it will be easier for you to measure things that way-I'll correct the measurements to reflect the distance from the desired CG.
Looking at a catalog your engine is 5 1/2 Oz lighter than my Saito 180. You propellor and engine mount are smaller than mine, which is about 1 Oz. less weight or 6 !/2 Oz total. I suspect that the center of mass of your engine is closer to the CG point than mine. The 2 stroke G90 will be shorter than the Saito 180 ( and the Saito has a rear mount carb). At a rough guess, the centerline of your glow plug is about 2 closer to the CG than mine.
I will recalculate the balance with your new numbers and get back with you as soon as I can.
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Super Kaos 90?? - 
RE: Super Kaos 90?? - 