MarkD

Has anyone built or flown one of the Super Kaos 90's as published by Model Airplane News ( 73 in. WS ~1000 sq. in, 90 2 cycle/120 FS?)

Thanks,


Mark D

flht99b

My Feedback: (36)

I didn't build it but owned and flew one. Excellent flyer, was powered by an OS 108. Was even more graceful than the 60 sized version. Ed M.

MarkD

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.

Do you remember what yours weighed?

Thanks,


Mark D

OUHOZER

My Feedback: (11)

Hi Mark,
Were can I get some info on this plane.
What issue MAN was it in.
Is this a kit; ARF; or a scratch build.
Thank's,
Hoss.

MarkD

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.


MarkD

RCDENT

My Feedback: (2)

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.

Dewey Newbold
San Antonio, TX

MarkD

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.

I'll post a pic when I get it covered.

Mark D.

Jim Finn

My Feedback: (2)

I made this plane from those plans but I made it electric. I have not flown it yet but it is ready to go.

MarkD

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.

MarkD

Here is another shot.

MarkD

One more

Jon Wold

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 :-)

PointMagu

My Feedback: (11)

Yeah...beautiful build:



PointMagu







"Ah yes, snakes in the cockpit..."

Vintage

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?

MarkD

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.


Mark D. Fain

Vintage

Thank you for volunteering your knowledge and time. I was mainly interested in the fuse strength, by putting lightening holes in it. I have removed approximately 2 oz of weight from the tail section, by changing from 4-40 to 2-56 linkages and pushrods and control horns, and the lightening holes in the rudder. I do not do any violent maneuvers. 4-points and knife edge is about the worst.
I can't give you the information you requested, as I have the engine on the break in stand, and the weather is not co-operating. The weight I added is not permanently installed, so rebalancing will not be a problem. Moving the battery forward a couple of inches, as well as the servos, should allow at least half of the lead to be removed. Every ounce helps.
Thanks

MarkD

If you get things back together, and have the time to measure things I'll be more than happy to run the numbers for you. I forgot to ask where you have the plane balanced- in the middle of the CG on the plans?

If you put your servos were I had them on the plan, and move them back into the wing bay just in front of the aft former it is a distance of about 28". Thats quite a lot. We have to factor in the weight of the new pushrods ( and the relationship of their CG to the planes desired CG). We also need to consider the weight and CG of the long servo leads that will be removed. It MAY be that most of the ballast, if not all can be removed.

I'd recommend using carbon fiber tubes for pushrods as they are the lightest/strongest unless you go to a pull/pull cable system.

The calculations are simple once you have all the numbers to hand- it's just a matter of getting all the plus and minus signs going the right way.

Whatever I can do to help, please let me know.



Mark D. Fain

PointMagu

My Feedback: (11)

Here's the MAN plans:

CG is dead center of the cord appears to me. This is where I've balanced mine. Flies sweet...

I located my radio gear aft behind the cradle for the Robart air cylinder.

PM

Vintage

Wow!!! Maybe I am trying to balance this Kaos at the wrong place. The plans call for a CG at
5 1/2 inches behind the leading edge at the root. This is where I have been trying to balance the thing. Tomorrow I will draw my wing out, and get the mac, and then see where my CG should be. I like to be in the 30% area for first flight.

Vintage

Finally have the measurements on my wing. My wing plans show a 16" chord at the root and
11 1/4 in at the tip. 36" half or 72 total span. I think the plans I have are shrunk.
After finding the MAC, the 25% CG would be at the 4 1/2 mark at the root, 30% CG 5" and 33% 5 5/8". I have been trying to balance at the 5 1/2 mark which would be on the tail heavy side. Moving forward to the 30% will require more lead. I did not receive all the pages of the build article in MAN, so I do not know if the CG point was mentioned in the article. Some copiers shrink drawings, so all my measurements would be wrong on the full size. Can anyone give me the CG point in inches at the root.

PointMagu

My Feedback: (11)

I have the original plans that I built from. I'll check them out tonight while covering my Curtiss Robin wing and post later on.

PM

PointMagu

My Feedback: (11)

Here it is...directly off my plans, (foam wing version):

5-1/2" at root, from the leading edge.

I'm running an ASP 108 so I need no lead up front. Also, mine is a tail dragger with all servos in the wing saddle area.


PM

Vintage

When you mentioned that it looked like yours balanced dead center of the cord, it bothered me a tad. I thinkj I will start out at 5 1/2 and proceed from there. Will have to get used to the new flying field with my kaos 40 first. Haven't flown off of grass for over 20 years. Gonna have to be careful not to try and yank it off the ground too early. Thanks

Vintage

Not as nice lookin' as yours, but should be able to see it. If I build another, it will have a thinner wing and a couple inch shorter tail. Might have to try my ASP 1.08 in it.

PointMagu

My Feedback: (11)

Thanks for that but your version looks great, too!

I usually place checkboards on my planes. The guys at the field always tease me about it. When I showed up with the Kaos, they wanted to know whose airplane I had, lol...

The flourescent yellow really shows up in the air. I didn't follow through with the winged pattern on the undersides so that helps alot to determine if I'm inverted or not :-)

The 1.08 has issues flaming out so I'm adding a 42% Products glow driver onboard this Spring. We'll see.

PM