I purchased a Bridi Super Kaos Junior kit on Ebay only to receive the kit and find over half the kit and hardware missing from the box. I worked out a deal with the seller and just kept the kit. None of the parts to build the wing were in the box. Thanks to several great modelers on this site I was able to fabricate a new set of wing ribs and get started on the wing. I'm still not sure what size of engine I want to power the model with. I grew up flying glow engine powered model airplanes but for the last few years I have almost exclusively flown electric powered models. I have a motor that would power this model nicely on 4S to 5S Lipoly power but I'm not sure that an electric motor would do this model justice.

Pictured is the box full of parts and junk I purchased off Ebay. The plans are chewed up a bit but still okay. The second photo shows the wing ribs fabricated from the drawings I received off of this forum. Thanks guys!!!

I had a Great Planes wing jig laying around so I decided to use that to build the wing. After fabricating the wing ribs the other parts of the wing structure need to be fabricated. In my opinion the model is overbuilt but I wanted to stay true to the kit. The 3/8 in sq hard balsa spars were matched in pair according to weight and then notched to fit the wing ribs. The sub-trailing edge stock was also notched. I used a jig setup on the scroll saw to quickly and accurately create the notches.

I was able to get panel set up on the wing jig. One change I did make to the structure was to redesign the front wing dowel hold down system. A 1/4 in thick balsa rib was cut and a pocket created for the 1/4 in diameter dowel. Once the wing is covered the dowels can be installed easily and accurately.

One final post for tonight. One other small change I made to the original wing plan was to shorten the rib faces slightly (by 1/8 in) so that a sub-leading edge strip could be used. I have used this method on some of my original designs and find it to be a great way to create a leading edge. The sheeting glues to the ribs and overlaps the sub-leading edge piece creating a nice solid wing leading edge.

Very nice modification. That is what makes building such a large part of this hobby. Ability to "tailor" your planes to the way You want it to be.
I don't think you would disturb the authenticity going electric. You need to decide if you want to hear the scream of a 2 stroker with a nice light trail of exhaust or you want a clean oil free buzzing plane? You'll be the one flying her. But you are retracts.... right???
Your workmanship is clean and first rate. I'll be sure to stay on top of this thread.


DM

I like how you did the dowel, I'll have remember that one! Nice build so far!

FB

Very nice build thread! Chuck, can you please add it to the Builds Sticky?

I also prefer the sub-LE method. I never liked trying to feather sheeting into an LE when it's glued on top. It's never as neat. Notching the TE is also worth the extra time. It's a much stronger joint and it keeps the ribs square. Great job!

Since you're doing mods, have you considered a built-up stab à la the Dirty Birdy? I built my Super Kaos Jr this way and I'm convinced the elevator control is a lot smoother. I was also told that the thicker tail surfaces will help to eliminate high-speed wagging.

I'm looking forward to more posts.

David

I built mine a couple of years ago from a partial kit like you have
and the RCM plans. I built it pretty much stock and have flown
the snot out of it the past 2 years.

Its designed for a 40 size motor. The RCM plans show a K&B 40.
I shoehorned a TT46 Pro into mine and it was a tight fit.

The radio compartment is also pretty tight with very little
clearance between the aileron torque rods and the elev/rudder
servos.

Its a terrific plane and flies just like a Kaos should.

Thanks for all your kind comments guys!

David, that horizontal stab modification looks awesome! Should be too hard to do.

Pros and Cons to glow verse electric: shoe horning in a modern glow engine, noise and cleanup mess : ), Electric conversion would require some sort of battery access hatch which could possibly weaken the fuse structure although there wouldn't be a vibrating glow engine up front. I'm really undecided!! Thats why I started the construction project with the main wing panels.

Just a small update. I was able to get both wing panels framed up. I hate building wings!!

Looks good Rob. Nice for a week's worth of effort. At this pace you'll have this done by the end of the month.

Jim

I have not posted any updates for a while. This is due to other projects taking priority such as assembling a Tower Hobbies ARF Kaos and drawing up a Hanno Prettner SupraFly 25 in CAD so that the parts could be laser cut.

I have decided to make my Super Kaos JR project electric powered since the other Kaos is glow powered using an O.S. AX 46. The motor I have chosen for the Super Kaos is a Hacker A30-10XL on 4S Lipoly power. This should easily power the Super Kaos if I can keep the weight to 5lbs or less. I think this is possible. Instead of building the horizontal stabilizer out of sheet balsa I chose the wood carefully and went all built up. Even though the wing is only slightly smaller then the Kaos ARF wing, it weighs quite a bit less. I had to totally scratch build the wing for the Super Kaos but this allowed me to select all the balsa wood carefully. There will be many further modifications to the original plans in order to make the model successful as an electric. Stay tuned.

I've finally finished this project. The finished model weighs 71 oz RTF with 4S Lipoly. Power comes from a Hacker A30 10XL brushless outrunner motor spinning a 10x10 or 10x8 propeller. I haven't test flown the model but with this power system I should see level flight speeds of close to 100 mph +. Battery is accessed from a removable top hatch and the wooden cowling is removable. Two JR DS 3421 servos control the ailerons.

Rob

Great article in R/C Sport Flyer magazine December 2008. [sm=thumbup.gif]

Jim

Have you test flown the electric Kaos yet? I have also built from the same kit years ago, and have built many more from the plans every time I dig one in. The one I have now has a OS46LA in it and weighs in at 4lbs 13oz. Would like to try a modern one with electric like you have. Matt

Rob,

I was wondering if you managed to finish the SF 25 project you mention above? If a laser cut kit is available, I'd be most interested. Do you have a picture or two of your model?

TIA, David.