Relative attack angles of wing and tailplane

[Trevor 25]

Hi,

Does anyone know the answer to this? I am building a CAP232 from scratch (don't ask why, it's just one of those things I have to get out of my system). Something I have never really thought about before, should the angle of attack of the tailplane be parallel to that of the wing or should it be tilted slightly up (to give the tail some extra lift) or down (for whatever reason)? If the angles are different, by how much?

 

Wingspan: 57"

Fuse length: 48"

 

Happy Easter

Edited April 30, 2006 by Guest

[Trevor 25]

Thanks, that is what I was after.

[orange_rc_pilot 0]

 

Hi,

Does anyone know the answer to this? I am building a CAP232 from scratch (don't ask why, it's just one of those things I have to get out of my system). Something I have never really thought about before, should the angle of attack of the tailplane be parallel to that of the wing or should it be tilted slightly up (to give the tail some extra lift) or down (for whatever reason)? If the angles are different, by how much?

 

Wingspan: 57"

Fuse length: 48"

 

Happy Easter

 

Hey there Trevor,

 

If you are going to change the angle at all, then I suggest having the frontmost part of the plane tipping down, so that the back of the tail is raised slightly. Don't overdo it, though! A couple of degrees is more than enough. Angling the tail in this way can let you get away with a slightly underpowered power system, but it may cause the nose to pitch up if you punch the throttle.

 

It will also fly great with no angle at all.

 

Hope this helps!

 

[Martin 0]

 

Quite a few modern aerobatic models have both at the same angle (i.e. zero decalage), but David A. Scott's book "Airplane and Radio Setup" goes into quite a lot of detail about why he thinks this is a bad idea, and recommends setting the wing at 0.5 degrees of additional incidence relative to the tailplane - i.e. the tail is in line with the anticipated direction of travel, and the wing is angled upwards an additional 0.5 degrees. (This recommendation is for neutral stability with a symmetrical airfoil.)

 

His argument is that zero decalage with a symmetric airfoil requires the use of additional up elevator trim to maintain the angle of attack of the wing. While this does work, this has a different effect depending on the airspeed, and so the aircraft will tend to pitch up at higher airspeeds.

 

[Bravedan 106]

Errrrr, Guys, you do realise the original question post was made (and answered, though the answer has long since been deleted) in 2006, not 2016!?

[Martin 0]

No, I hadn't noticed that! The thread popped up in my "unread posts" due to the new reply. I did think it was odd that Trevor's reply appeared above the other reply, but I hadn't realised why...

[orange_rc_pilot 0]

 

Errrrr, Guys, you do realise the original question post was made (and answered, though the answer has long since been deleted) in 2006, not 2016!?

 

Yeah, I did realise that

 

I just wanted to post something, since it would be my first post.