SeamusG

Thx for the heads up Crate.

I just checked my elevator. There is no slop with my fingers just outboard of the "dowel" ends. However if I place my fingers 2/3 of the way out on each elevator there is flex. I then tested the flex of each elevator half. It appears that the flex is due to the soft balsa used to construct the elevator. I tested the individual elevators of my ShowTime 50 ARF (structure is perimeter frame with pretty hard balsa stock). There is no appreciable flex. My conclusion is that the flex is related to elevator material and structure rather than the hardwood dowel.

With that said, and to your point that this is a (pattern) aerobatic plane - got any suggestions on adding rigity to each elevator without adding too much weight? 1/64 or 1/32 ply sheeting? As the plans don't (appear at first glance) provide suggested throws, what throws are necessary for a rollrate of 1 second or a 1/2 elevator loop of 17-20 seconds? Are they pretty small (10-15 degrees) as compared to a 3D 45 degree elevator throw?

Just sign me - newbie to all this ...

tschuy

My Feedback: (1)

I usually will toothpick pin my dowels to the elevator halves which adds a good deal of strength to those glue joints. I typically will drill a 1/16" hole through the hardwood dowel into the balsa and then will wick some thick CA into the hole and insert a toothpick into it and let it cure. Once hardened then cut off the excess and sand smooth. I would also be careful with the grade of wood used on my control surfaces and use medium to hard grade of balsa if using plank type control surfaces and not buildup. To fix your problem it may be easier to glass one side of the surface with 2 ounce cloth and sand smooth with filler. Using ply and gluing it to the existing elevators halves would add a lot of weight in my opinion.

Perhaps someone else has a better solution?

Cheers

CrateCruncher

My Feedback: (1)

SeamusG, If the dowl is stiff I wouldn't worry about the balsa flex. It becomes less important as you move out to the tips because the areas see less load in flight. The final covering (Monokote for instance) will stiffen the balsa quite a bit. If you have some scrap try covering your elevators and see how much stiffer the halves get. As Tschuy said, 0.5 oz fiberglass/resin would stiffen it even more and toothpicks are cheap insurance. The reason I mentioned the dowl is because I've had some that were soft as a Tootsie Roll.

Pattern planes tend to be set up with lower control surface deflections and lower servo ratio than sport or 3D planes. Low servo ratio is where the servo rotates 45 deg but the control surface only moves 10 deg. It allows for better precision (and less load on the servo). I'm not that good a pattern flyer but I like flying my Kaos with +/- 12.5 deg for both elevator and ailerons. Rudder is as much as I can get without banging into the elevators.

Elevators are very effective on the Kaos. I never use the full 12.5. I DO use full aileron though.

SeamusG

Thanks CrateCruncher

I've used and am happy with the low servo ratio approach. I use the approachwhenever possible.

Guess I'm going to have to get a degree'd device for checking control surface angles. Aeroworks (local Denver area) has a simple device that should work.

SeamusG

CreateCrusher,

Do you have a standard for engine right thrust? Others have suggested 2-3 degrees for various planes. Works great for a SIG Somethin' Extra. The Killer Chaos instructions do not address this issue.

TIA,-

tschuy

My Feedback: (1)

Go with 2 degree's right thrust which was pretty much the standard on the Kaos fleet. Then figure if it needs more after the first few flights. On my Bridi XLT, 2 degree's worked perfectly during the verticals without any trim input from the rudder to keep it tracking straight.


Cheers,

SeamusG

Thx Tim - 'preciate it.

tschuy

My Feedback: (1)

You're most welcome SeamusG.

Do yourself a favor and lateral balance the wing while it is attached to the fuselage BEFORE applying the covering. You'll be surprised how much it takes to get the wings balanced. And yes, it does make a difference how the airplane tracks through the air. As for the precision degree device, unless you plan to compete with this airplane at expert level pattern, I personally feel it's a waste of money. Go get the deflection meter from Great Planes and you'll be good: http://www3.towerhobbies.com/cgi-bin...?&I=LXK260&P=0

Cheers,

SeamusG

So far I've lateral balanced at the same time as balancing for the CG fore-n-aft. Accepting the cosmetic uglies of having exposed lead weights glued on to the wing tips. 'Bout time to clean up my act and lateral balance before covering as it's independent of the weight of the covering.

At $11 plus $6 shipping ($17) I can get the GP one or I can drive over to Aeroworks and pay $20 + tax. (and I don't have to wait  for UPS). If I need to order something else from Tower it makes "cents".

TTFN,

tschuy

My Feedback: (1)

To add to my prior post...

If you do find that 2 degree's of right offset is not enough (IE it takes a bit of rudder trim to get the airplane to track straight in the verticals) then its easy to add another degree by putting a small washer between the engine mount and the firewall which will give you another degree of right thrust.

As stated earlier, my XLT tracked nicely with 2 degree's of offset with near zero rudder trim required.

Cheers,

Gray Beard

My Feedback: (-1)

I have been making my own degree meters for years from scrap wood I have in my shop and using the 180 degree print out I get with gas engines for the face. I just reduce it to the size needed for my meters. Simple and free.

SeamusG

I guess that I could scan a 9" 360 marked disk,edit it on zee computer, print it, glue it on some stock and (in my best Jackie Gleason accent) Awaaayyy We Gooooo!

Good stuff all.

So I can't align the darn thing on my scanner - so SUEme.

CrateCruncher

My Feedback: (1)

Seamus,
You don't have to use a degree meter. I speak in degrees because there are several scales and different tail configurations for the Kaos/Chaos planes. To convert from degrees to inches you would measure the length from l.e. to t.e. of your elevator surface in inches for "L". Then measure up from a flat surface to the point of the trailing edge and call that height "H". The height of the trailing edge at 12.5 degrees would be length times the sine of 12.5 degrees.
( H = L sin 12.5 )

So if your elevator L is 2.5 inches, the deflection H from the table should be around 0.54 inch higher than when its at neutral. H = 2.5 x 0.216

SeamusG

Having a minor in math ... Why use the basics when ya can use a toy?

Just kiddin' ... Always appreciate a smack upside the back of the head. Em, got this yellow slip-stick on the shelf - ought to be pretty easy - think it's a Pickett (as in Wilson or "don't your dare do that in public") ...

squeakalong

My Feedback: (8)

Gotta love the humor here...!

Soft landings.

Joe

Broken Wings

My Feedback: (20)

I've started building the wing on my Killer Chaos using a GP wing jig that I picked up on *bay. It's the first time I've used a jig and I like it MUCH better than building off the board.
This is my second Bluejay/Bridi kit. I built the Aircruiser 60 and it's still flying with an old OS FS 90. I really like these kits. They build into a pretty tough model that seem to hold up much better than any ARF's that I've owned.

I'll buy more kits from Bluejay.

SeamusG

I'm with you on using the wing jig. My wing ended up very straight. It also gives you the flexibility to remove the wing from the board, turn it over, hold it up, whatever. You can alter the build sequence because you have full access to everything.

sailormc

Seamus-Thanks for the great thread, just found it. Nice build and good pictures. I just finished building an original Birdi Killer Kaos from one of his kits. Purchased a long time ago. I am using an OS 61 also. Will add the pipe after flying for a while.

I'll post pix when I take them. Joe Birdi's instructions call for building the wing upside down and leveling the ribs with 1/2 in. spacers at the rear of the ribs. Worked great and the wing is flat on top with the dihedreal on the bottom. The leading edge sheeting is put on with titebond. Glue the leading edge and let dry. Apply titebond to the ribs, while wet transfer glue to the sheeting and release to dry. When dry use an iron to heat the sheeting and glue and bond the sheeting to the ribs. Works. Two servos outboard in the wing.
I'll scan and post his original instructions when I get back to my scanner in October.

Cant wait to fly it.

Bob

SeamusG

Hey Bob - I've heard the "after dry use heat" method of madness to reactive the glue in a couple of threads (as well as the kit's instructions). Is this your first time using the technique? If not - does it really work well? It looks like a technique that needs to be tried.

There a quite a few club members that have built / flown Chaos'. They all say that I'll love the plane. I gotta finish covering my Hog Bipe kit so I can get back to the Chaos build!

sailormc

Seamus The heat and titebond worked swell for me. Just like the instructions said. I'm planning to cover next month. stitz Lite and their paint. Pix to follow.

Bob

SeamusG

Hey there experienced Chaos builders - Ineed some feedback. Iattended a contemporary pattern contest for the first time. Ihad the chance to scribe for a judge that had won several national titles in the 90's - sorry, really lousy with names. I also looked at the new stuff. Got me asking questions at the field. Everyone likes the Bridi Chaos - duh!

Here's my question (kinda long winded): Today's planes have rounded fuses where the bottom transitions to the sides and, of course, where the sides transition to the top. I'm guessing to better transition from normal flight to side (knife edge)to inverted and back. Is there any benefit to adding small rounded formers to the top and bottom of the fuse and adding some 1/16" sheeting? The SIGSomethin' Extra uses these to build up the top sheeting of the fuse and canopy. Or - get REALSeamus! Just build it straight and enjoy it!

Thanks for your input ...

sailormc

Seamus Finally took some pictures of my Birdi Killer Kaos from one of his original kits. Power is OS 60 Pipe will be added later. Covering with Stitz Lite.
Bob

Gray Beard

My Feedback: (-1)

I should take some photos and post so you can see some of the changes to the planes as the years went by. I have a Daddy Rabbit that won class 3 in 1966 then my Kaos that won in 1970, and I think in 72 and 73?? Then I have an Ariel that competed in the mid and late 80s in the 2M class. The changes made the planes a lot more stable over the years but one look and you can see they were all pattern planes and how they progressed over time. You look at the Ariel and you can see the planes that compete today, not a lot of changes to the design. The Kaos wasn't the best plane in Knife Edge so I added more fin and rudder to mine, it made it better but now in any cross wind it weather vanes a big bunch, that action and reaction thing at work again.

SeamusG

I had a chat with a 20+ year pattern competitor at our club meeting last night. He brought his contemporary pattern 2M plane. He CD'd a pattern competition this past weekend at our field and I had a chance to scribe for and observe some past national champions (they were both judging and flying). 10-20 mph quartering breeze. Fun stuff to watch and learn from. The most significant item that I learned from this guy about the Bridi Chaos - it was designed to be flown fast. If I understand correctly the design wasn't too good at slow speed maneuvers that included a knife edge - faster ya go the less affect by the design.

With this design "feature" I'm curious as to the approach to be taken for a prop (OS61FX w/ std. muffler). My club member suggested something in the area of an APC 11x10, maybe back to an 11x8. What 'cha think?

Hey bob - your emperor has no cloths! What are you thinking about for a covering scheme? Is the pic of your pre-covering assembly w/ everything installed? Have you used Stitz lite before? If so, what are it's good / bad points? Enquiring minds are dangerous things.

Oh, btw, just spoted the Robart hinges. Pros?Cons?

Gray Beard

My Feedback: (-1)

[quote]ORIGINAL: SeamusG

I had a chat with a 20+ year pattern competitor at our club meeting last night. He brought his contemporary pattern 2M plane. He CD'd a pattern competition this past weekend at our field and I had a chance to scribe for and observe some past national champions (they were both judging and flying). 10-20 mph quartering breeze. Fun stuff to watch and learn from. The most significant item that I learned from this guy about the Bridi Chaos - it was designed to be flown fast. If I understand correctly the design wasn't too good at slow speed maneuvers that included a knife edge - faster ya go the less affect by the design.

Very true, they were designed to be fast. There was no box to fly in so you could use up all the sky you wanted. I had seen slow rolls that started and finsihed from end to end so far away it was hard to see the plane. Those guys were outstanding pilots!!! They still are but watching the old events were something very different.