karolh

I would like to change the shape or my Big Stick 60's vertical stab and rudder to a more conventional one which includes extending the height by approx. 2" to allow for the new shape and filling in the tuck at the front where it joins the top of the fuselage.

Is there anything major that I need to take into consideration so as not to affect the model's flying manners.

Karol

Acs_guitars

My Feedback: (3)

Just keep the control surface itself close to the same size (area) and you will have no problem. Most airplanes can use a little more rudder area anyway for more rudder authority in the air... you can always set a dual rate and trim the controls if you find it is too much.

Acs_guitars

My Feedback: (3)

The rudder area is what matters most, I would just trim down the stationary vertical stab. Something like this quick Paint rendition here... You will want to shape it so that it matches the style of the plane, my drawing is changing to a generic traditional style.

edit: By doing it this way you also end up with very little change in weight on the tail.

karolh

Your sketch shows a new line of thinking as I never considered trimming the stab or making it smaller than it is, but rather adding a filler at the bottom. Your outline for the top and bottom is in keeping with what I have in mind.

Karol

longdan

Can I ask why you want to do this? Are you having trouble with the round tail? Or is it just a looks thing? The reason I ask is that I am planning on building a .40 sized stik soon, but not sure whether to go for the round tail or a more conventional tail.

karolh

The plane flies just great with the round tail, but I'm tired of the unusual look and want to change to a more conventional looking tail that's all.

Karol.

Ed_Moorman

My Feedback: (1)

Why not copy an Ultra Stick tail? They fly well.

karolh

That's exactly what I planned on doing when Acs sent me his sketch, which got me thinking otherwise but I'm not sure that I want to reduce the size (area) of the vert fin.

I just wanted to make sure that my doing such a mod would not upset anything in how the model performs. Think I will stick to my original concept.

Karol

karolh

Ed, I did as you suggested and copied the Ultra Stick's tail and it turned out real well. The change in outline has really transformend the looks of the plane, no more ugly duckling.

Now I'm thinking of adding a rear turtle deck to make it look somewhat like an Ace 4-60. See the mischief idle hands can get into

Karol

OzMo

My Feedback: (3)

Hi.
I think kit bashing is great fun. I rounded off the tail of my son's LT40 because he wanted something different. The originator of the stick went WITH the rounded tail so it would be a little different. Funny HUH

karolh

Sure is, but what a drab world it would be if we all liked the same thing. I have completed the turtle deck addition to the Big Stick including a pilot and windshield. It was a real fun project.

Karol

Ed_Moorman

My Feedback: (1)

Karol,

Send me some digital photos so I can run one in my column.

[email protected]

Thanks.

Ed_Moorman

My Feedback: (1)

Let me go ahead and cover the basics of vertical tail size.

In the first place, it is total vertical tail area that counts. It doesn't matter how you break it up into fin & rudder.

Vertical tail area is different from horizontal tail area, in that it can be too large, as well as too small. Too small and you get into yaw instability. This is not a panic situation. You have all seem planes with a slight yaw instability. Watch a scale warbirb especially if the tail surfaces haven't been enlarged for better RC flying. When he makes the first turn after take off, if the plane tends to slide sideways before the nose starts to track arouns, it either has a bad case of adverse yaw or a slight yaw instability. I've flown a lot of warbirds and I usually don't see much adverse yaw. If the tail gets really small, you'll also have to fly the rudder a lot.

Too big is also bad. Here you get into spiral instability. Again, the plane doesn't go from stable to massive unstable, it sneeks up on you. Spiral instability is where the plane doesn't want to recover from a spiral. The more elevator you use, the tighter the spiral gets without raising the nose. It is easier to see it in a turn. With a tail that is too large, the plane will tend to increase the bank in the turn. As you go around a 180 deg. turn, for example, you'll think that it was weird because you had to touch up top aileron in the turn. You know how a trainer flies. When you go around a long turn, you keep having to touch up the bank because it wants to roll out. Spiral instability is the opposite, it wants to steepen the bank.

When Flaps and I design a plane, we normally use 10%-12% on the wing area for the vertical area.

If you are going to kit bash, try to keep your new tail about the same area as the original kit area.

karolh

Unfortunately right now my photo capabilities are down but I will post some photos as soon as possible.

The original vertical tail area of the Stick was approx. 8.5% of the wing area and my bashing brought it up to 10% of the wing area, with the rudder having 45% of the total v/t area. The rear turtle deck adds a small amount of side area to the fuse that hopefully will enhance the Stick's KE performance.

Karol