BBriBro

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Kevlar, nylon, plywood, anything would be nice, oh well, I guess I'll make my own. I ordered from Desert Aircraft and he said each batch of kits is slightly different, sometimes you get more sometimes less, in the way of hardware, Hmmm, just not very consistent. I got the spinner and the fuel tank, so they said I "got a good one" I didn't even think to ask about the horns, or the tailwheel thingy, damn

mec

hi bbribro,

no, the tailwheel wire and the aluminium piece are selfmade ones.
the control horns are from GFK and are with the kit (sheet of horns).
also with the kit: spinner, 0.4L fuel tank, main gear, wheels, wheel pants, tail wheel and GFK plate for tail wheel, tinted canopy, 4 plastic angles as engine cowl mounts, 6# 4mm plastic screws.

fuel tank will be a 1/2 liter coca cola bottle.

mec

BBriBro

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Ok, so it seems then that I am only missing the horns. GFK? As in carbon fiber? Now that would be cool, I wouldn't care much if they were plywood, but I have no way to duplicate the GFK ones, hmmm. By the way, mine is completely framed up, ready for cover, it looks beautiful all together, everything fits well, even the canopy fits real good in spite of no "cut lines" molded into the plastic. I just took my time, trimming a little at a time till it fit well. After re-reading your post, My tailwheel bracket is fiberglass, I guess thats what the control horns are too then.

mec

GFK (Glas Faser verstärkter Kunststoff) stands for fiberglass.

mec

BBriBro

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Thanks, Learn something everday !! What is the recommended aileron throw? I think I read 45 deg for the tail surfaces, but haven't read anything on the ailerons, It's a chore to sand that aileron leading edge !!! I want to make sure I have enough bevel on it.

gwright

You can't get drastic throws with the ailerons the way they are stock (only about 30 degrees or so), so I used Robart Hinge points, and spaced the ailerons out 1/8" or so from the trailing edge (then sealed the gap with clear moneykote on the underside), thus allowing for more movement. I simply added about 1/8" to the trailing edge of the root cuff so the ailerons match the trailing edge,.. well,.. sort of,.. I'm not a great builder . The tail surfaces were "spaced out" the same way with robart hinge points and clear moneykote gap seals. I've got a bit over 60 degrees in the elevators each way to get a good waterfall. I can go another 5 degrees or so, but it doesn't seem to help, so they're "backed off" a bit. The control horns are glass, like PC board material, but the elevator horns are the wrong geometry. I used them, but could only get about 40 degrees of throw, so I changed them last week to some big black dubro horns, placed aft of the hinge line, so that with a long servo arm off the bottom of the elevator servos, the pushrod forms a 90 degree angle to the servo arm, and a 90 degree connection to the elevator, if you draw in imaginary line from the clevis connection to the hinge line. with the stock control horns, with the elevator in neutral, the hole is directly below the hinge line, which is normally good, but if you put the servo horn connection on the bottom to allow for a long servo arm, the angle is much greater than 90 degrees on the elevator connection, so you end up with massive differential, and the inability to get enough down elevator.

BBriBro

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Thanks for the info, I always strive to get the clevis directly below the hinge line, is this not the proper technique when extreme control throws are desired? Can someone list the pros and cons of this technique? what happens to the geometry as you move the horn behind the hinge line? Maybe I am too picky and it doesn't really matter. Back to the ailerons, I was thinking they might be real effective without rediculous throws, they are already larger than my 1/3 scale Laser on a much smaller airframe.

mec

according to the manual the ailerons should move 20° up and down with 50% expo.

mec

krayzc-RCU

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hopefully someone who has this bird and can do the rolling elevator/harrier will let us know the throw they have on the ailerons as those are barn door ailerons.......

i would think a lot should be happening with 30 degrees of throw on those babies.....

BBriBro

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Thanks MEC, I'll have to check, but I'm sure I have at least 20 deg

BBriBro

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Yeah true, they look like they would be very effective, but maybe you have to be extreme to get that kind of performance? I don't know, the kit was designed for that type of flying, therefore I would expect awesome performance even with the modest bevel they show.

gwright

if you draw an imaginary line between the clevis pin (attachment point of the clevis to the control horn) and the hinge line,..this imaginary line should always be 90 degrees to the pushrod, same for the servo. This will provide for equal movement in each direction without differential. The stock horns on the elevator of the funtana are directly below the hinge line, which is normally good, because the pushrod comes in parallel to the stab/elevator. However, they put the elevator servos right up next to the horiz stab, so to get long enough servo arms on them, you have to run the servo arms off the bottom of the servo, which means the pushrods go to the elevator at about a 20 or 30 degree angle, hence the elevator control horns need to be moved back to account for that.

krayzc-RCU

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gwright


don't you do the rolling elevator/harrier with your funtana?

gwright

Here's a quick bitmap. In the stock configuration, you'll have lots of differential leading to lots of "up" and little "down",.. plus the pushrod and horn get in-line with one another at full down, which could lead to a mechanical locking of the surface if the pushrod/control horn go "over center". That would really never happen due to the loads ont he elevator at full down,.. but it does create a spongy feeling elevator, and is generally "bad". the second diagram is how I have it now, which gives you 90 degree junctures of servo arm to pushrod, to control horn. I drew in the slanted control horn for illustration, although I'm simply using a large dubro horn, placed aft of the hingeline to accomplish this.
Proper control geometries are so important on helicopters that I designed a tool a few years ago that allows you to use those big un-drilled servo wheels, attach pushrod to tool, and mark location of the hole exactly at 90 degrees to the pushrod. I generally carry-over that same attention to detail to airplane control systems.

gwright

This clip shows mine in a rolling harrier circle after a hover and couple torque rolls . forgive me for being so high, but I only had 2 flights on the airplane before this one , and this was in front of a lot of people at the TOC, so I was being a bit more carefull than normal.
www.rccraze.com/funtana.mpg

I haven't measured my aileron throws, but they look to be in the 45 to 50 degree range (each way of course), with 80% expo,.. 100% expo is on elevator ( I generally don't fly using dual rates,..just one rate (high), with lots of expo).
I've also got some better batteries now, that have added 300 watts to the system (roughly another 1/2 horsepower),.. although,.. the takeoff to knife edge 1/2 loop, and the climb out of hover is only about 75%~80% throttle in this video clip, so power was "ample" to begin with

BBriBro

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A picture is worth a thousand words !! So the 1st illustration would only work with a small servo arm, which I guess doesn't give enough throw. So then how do you know how far back to move the horn away from the hinge line? Since you said you do not have a slanted horn, you are using a du bro giant scale horn, which is still perpendicular to the control surface.

BBriBro

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I studied your drawing again, If we did indeed have an angled horn on the elevator, you could still mount it close to the hinge line, in the stock location, and then just tilt it back till it was parallel with the servo arm, and 90 deg to the pushrod, but with a standard shaped horn, it will never be parallel to the servo arm, so as in my previous post, the linkage makes sence, but how do you know how far back to place the horn?

BBriBro

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gwright, I updated your bitmap to illustrate my question. This is fun. You'll see in the 2nd picture now, it doesn't look so "geometrically correct"

gwright

you have the right idea,..the important thing is to have the line formed from the clevis pin to the hinge line, at a 90 degree to the pushrod (to eliminate differential and give full throw ability),.. and you drew it like I have it done. I did the angled-back horn to illustrate the principle a bit better, trying to make it clearer.

BBriBro

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yes, the angled horn gets the point across, I was just curious with a straight horn, how far back to put it? To say it another way :

BBriBro

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I have sanded the bevel as far as I can go without cutting into the ribs, I can get 35 deg of throw on the ailerons. If I leave a slight gap at the hinge line, I could get 45 or so but I hate to do that. I think I will settle for the 35, looks like plenty

gwright

If you draw a line between the clevis attachement point to the horn, and the hinge line, it should form a 90 degree angle between itself and the pushrod. If you move the clevis in or out on the control horn, this changes a tiny amount, so figure you want 60 degrees of movement on the elevator, and the servo moves nominally 30 degrees in each direction (60 degrees total), then you need a 2 to 1 ratio, so whatever length servo arm you use, you need 1/2 that length in control horn, measured fromt he hinge line to the clevis attachement point. Here's another drawing. I tried to illustrate a bit more clearly the relationship of the pushrod to servo arm and control horn


[QUOTE]Originally posted by BBriBro
[B]yes, the angled horn gets the point across, I was just curious with a straight horn, how far back to put it? To say it another way :
]

krayzc-RCU

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does anyone have wing bags for theirs if so who fit with no problem?

BBriBro

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I finally borrowed a friend's camera, here is my progress so far.

BBriBro

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it wouldn't let me put all the pics on one post