Hi Guys:

I’m building a KAOS 60 from an old Great Planes kit that I had stored away. (This is a revised version of the original KAOS 60 that was designed by Joe Bridi.) I have a question about the (metal) elevator horn supplied in the kit: Does anyone know why the horn has a forward offset? I measured the angle at approximately 17 degrees off the vertical. (See copy of the plans showing the elevator horn.)

From what I can tell, this will result in less down elevator movement, and more up. So the overall effect is elevator differential.

Does anyone know why the elevator was designed this way, and what effect it will have on the flight performance of the airplane?

I have built five KAOS kits over the years, and I’ve usually swapped out the offset elevator horn and replaced it with a conventional horn (with zero offset). I have never noticed any problems with this setup.

Any information on this will be very helpful. Thanks!

You will need the connection of horn to pushrod, directly over the hinge line. It could be the way the horn is mounted in the LE area of the elevator, the degree of offset will accomplish this. This is my opinion, but not necessarily right.
Did you draw that horn on the plan's ?

Crank

No, I didn't draw the horn on the plans; that is the way it was drawn on the orginal copy of the plans that came in the kit. All I did was draw lines over the horn to show the angle that the horn is rotated forward.

I used it right from the kit in 1976 when i built my first one. I never had an issue with having enough down or up to do what i wanted... Only Joe would know why... I just did it and it worked fine... Mine is still flying and when i was younger i spent more time upside down than right side up.... if you have the ones with the offset and you are not going to use them, I'll buy them from you? i have a couple of short kits i had cut for me and will need the old horn.... Let me know....

the Aleron horns had upset as well.......

enjoy... I covered mine with polyestor and dope then finished with K&B primer and paint... It's bullet proof... if you crunch it you take home a back of bones but it doesn't break except for teh nose... It's been glued on with hotstuff and micro dirt in between events at fun flys... I've taken many first place trophys with this airplane... the super Kaos is good but never as good and durable as the first open face... By the way... No matter what i tried with the super K including built up tail surface, i never got rid of the Kaos Wobble... I just renamed mine "La Puta" and the judges for pattern in Mexico loved me.... I flew FAI intermediate with the super K covered with Monocote and spring airs and an OS FSR 61 and mac tuned pipe.... It's got Character....

Tommy...

I have plans for the UFO, Dirty Birdy and Super Kaos. All show the same setup with the slanted horn. I assumed it was for differential thow.

[X(] ....Tom for the age that K must be by now, i think you should rename it " la Putisima"

A slanted horn would be done to induce differential throw. I wouldnt change it. I'm not a Kaos expert, but I do remember my Super Kaos 40 (in 1977) having the same differential elevator throw. I'd trust the designer. It was a very well proven airplane.

As Joe puts it in the UFO article - "to equalise the response of the aircraft to elevator inputs". This type of mechanical differential set up was quite common in reed days to equalise the diameter of inside and outside loops and as shown will give more down than up. A bit redundant now with proportional control and the ability to adjust everything using transmitter software.

Ray

Typically if any differential is needed, slightly more down than up is desirable for aerobatics.
Odd thing about the Kaos is the forward slanted horn on the bottom side of the elevator gives more up than down. A bit counter intuitive but still, its a proven formula on that model so I wouldnt change it.

Again, with computer radios its a bit of a moot point anyway, you can dial whatever differential you want in about 2 seconds. Gotta love technology!

Thanks... this explanation sounds logical, based on the fact that the KAOS design goes back to the early 1970s when radios were limited in the amount of features that could be programmed into them, (compared to modern day radios.) Even something as simple as dual rates and servo reversing was unheard of back in those days. We've come a long way since then. Thanks to all for your input. [8D]

Mike,

I hesitate to disagree but I think the swept forward horn on the bottom will give, as it should, more down than up.

Ray

to reverse a servo in the olden days of the 70's, we used to open up the servo and change the wires going to the potentiometer.... I used to be the kid...now i'm the old man...

Ray,
Trust me, Mike is correct. More up than down.

Dave

Gents,

Trust me, Ray is correct. More down than up.
It is from the period of the reeds. In that period "full throw" was the adjustment for the dimension of the loops,
An example, the Taurus, Ed Kazmirski, but already in 1961!!

Cees

Dang, I just layed it out and YES more down than up with equal pushrod travel.

I stand corrected.

Dave

Hello Dave,

You, from the Wright Flyer I will never forget

Taurus Flyer



photographic memory

Agreed. Back before computer radios, this form of mechanical influence was about it as far as our choices went. Me, I always thought that it worked backwards from the desired direction - but I don't argue with Joe Bridi - nosiree.


Ed Cregger

Ed,

I still use these principles to have max torque from my, not digital, servo's.
I do not need a modern computer radio for that and still use my old analog Multiplex Profi.

Second reason to use these linking is; the time to reach endposiions is the longest possible for inside and outside loops and this limmits the gyroscopic forces of the propulsion engine when starting small loops.
I do give some rudder input when starting a small loop, just as the moment of lifting of the tail of a taildragger during start when tho model has a high "nose up" ATTITUDE.

When you pulse a loop with the reeds radio the plane also can waggle the tail as with little rudder deflections because of the gyroscopic forces of engine and propeller! The reeds servo's were "fast" the old proportionals "s>l>o>w>e>r".

What???? Taurus long tail? Yes because of the reeds radio and not only for elevation also for direction! Thanks Ed for learning us this all, let's not forget.


Cees

Mike,

This is an interesting post.
(A little bit off topic but maybe interesting to read.)


I do use always one servo for the both ailerons, so this will never be my problem but;

Read.

When using two servo's for the ailerons and program the differential in the radio and not in the linking.
When making a fast ailerons input, faster as the speed of the servo's

Than the downgoing aileron servo does reach the endposition earlier (less throw to do) than the upgoing aileron servo.

So as long as the up going aileron is moving after that you do not have the right differential. (little bit flapperon for a while!)

Some points to think about,
Make the differential for the ailerons in the linking and fine adjustment in the computer radio.
Use one servo with the differential in the linking when you do use less fast servo's, they need much less torque and power because of the aerodynamical balance of the ailerons. Your both ailerons always have the right speed!!



Cees

quote:
they need much less torque and power because of the aerodynamical balance of the ailerons. Your both ailerons always have the right speed!!



Cees



??


DM