Battson
Well-Known Member
Hey all,
Been such a long time since my days of study that I can't remember how to do this, can you help:
I am putting ribs on the tail of my Bearhawk, to change the horisontal stabiliser's shape from a flat Maule-style stabiliser, to a symetrical aerofoil shape. This is a standard "upgrade option" offered by Bearhawk Aircraft, except I've made my own ribs from a drawing they provided.
Now, obviously the aerofoil is more efficient than the flat stabiliser, so the native angle of incidence built into the tail has to be reduced (which is the whole point - grab a few kts for free, improve control effectiveness). The guys in the community have only recently started installing this upgrade, and I am not aware of any flying example (yet). Certainly there's no "bank" of data to compare and contrast.
Is there a straightforward and relatively accurate way of calculating (estimating) what the reduction on incidence should be?
The number being banded around the support group is about 50% reduction (from 4o to 2o), but I am interested to check the math and learn something in the process.
I realise some people find the Bearhawk "twitchy" in the pitch axis, so I'll say now that increasing control sensitivity is not my goal. Mostly I am after reduced drag for airspeed, and to a lesser extent, increased effectiveness for low speed ops with CG near the limits.
All thoughts welcome.
Been such a long time since my days of study that I can't remember how to do this, can you help:
I am putting ribs on the tail of my Bearhawk, to change the horisontal stabiliser's shape from a flat Maule-style stabiliser, to a symetrical aerofoil shape. This is a standard "upgrade option" offered by Bearhawk Aircraft, except I've made my own ribs from a drawing they provided.
Now, obviously the aerofoil is more efficient than the flat stabiliser, so the native angle of incidence built into the tail has to be reduced (which is the whole point - grab a few kts for free, improve control effectiveness). The guys in the community have only recently started installing this upgrade, and I am not aware of any flying example (yet). Certainly there's no "bank" of data to compare and contrast.
Is there a straightforward and relatively accurate way of calculating (estimating) what the reduction on incidence should be?
The number being banded around the support group is about 50% reduction (from 4o to 2o), but I am interested to check the math and learn something in the process.
I realise some people find the Bearhawk "twitchy" in the pitch axis, so I'll say now that increasing control sensitivity is not my goal. Mostly I am after reduced drag for airspeed, and to a lesser extent, increased effectiveness for low speed ops with CG near the limits.
All thoughts welcome.