elevator to wing relations
 

Is it critical that the horizontal stabilizer is a certain hight above the wing or is it solely influenced by the incidences?

RE: elevator to wing relations
 

The vertical location depends on, but is not dictated by the use of the airplane.
If you're seeking neutral response upright and inverted as for a patten plane, the horizontal is -generally- located in line with the wing.
Other than that one instance, putting it where you want it works just fine.
And note pattern planes also -generally- have zero incidences for the wing and tail.
Your plane may need some for its purpose.

RE: elevator to wing relations
 

Paul's comments don't really get into the depth that the subject can go and neither will mine (sorry).

But one thing I might disagree with Paul about - and that is that sometimes the vertical location of the horizontal seems to be tied to the intended use of the airplane - think about the type of airplane you are considering and do some lookup and research on the net. It is interesting for example that the really big full scale heavy lifters have T tails. The people haulers have more conventional tails. Aerobatic RC non-scale ships line up everything (at least the new ones, the older ones had high tails and low wings). Older power free flight contest models have wing on pylon and low tail. Full scale aerobatic ships tend to have low wings, some mid wings and tails everywhere except on the bottom of the fuselage and the top of the rudder - And so it goes.

The thing is also that for every 4 examples you can find there will be an exception which keeps it really interesting.

RE: elevator to wing relations
 

I wonder about the T-tail on the full-scale heavy lifters.
The Antonov's don't use it, but "embrace" many of the other features of similar western airplanes.
I have a feeling the Antonov way is the correct way, for an airplane which might be in an active combat area. With the horizontal on top of the vertical. any weakening of the structure in the vertical due to combat damage requires a more robust construction.
With the horizontal on the fuselage, the vertical doesn't need the added structure to support the load at its upper end.
There may be esoteric reasons for the T-tail, but when Boeing competed with Lockheed for the C-5, their plane was a precursor for the 747, with a conventional horizontal.
Planes aren't always designed with the best aerodynamic features. some sex appeal slips in once in awhile. :)
Except for the Ruskies. Their planes temd to be more practically designed, if ineptly executed.
I recall inspecting the removable gun tray for the MiG-21. It was maintainable with a wide blade screwdriver and a fits-all.
Next to it was a USAF GBU-10 laser guided bomb. I counted 8 different styles of fastener just on the guide-head, from slot screws of varying sizes, philips heads, hexheads, and bolts which need special sockets to work with.
The guys working with the MiGs said after long periods of non-use, all they had to do was kick the tires and light the fires.. the F-4s they also used took much to pre-flight, and fix the problems that occur just when it's sitting still.

RE: elevator to wing relations
 

You know that is right! I had looked at the C5 and the like and figured that they had some aero reason for the location but aside from the structural weight needed (which has to be just enormous to keep the tail on with the possible loads that will be applied in normal flight much less in sideslips and combinations) how much do you suppose they put in for battle damage. It is the height of bad engineering to always assume that with our superiority in weapons that the landing fields will be friendly and the skies clear!

I keep seeing numbers in tons, staggers the mind. I agree about the Russian designs. We tend to go to extraordinary lengths to save an ounce, but our reliability and maintainability guys must drink too much coffee!

Those are very good points Paul. I had forgotten completely about the Antonov, I just remembered the first time I walked under the C5 tail and saw clouds blowing by underneath of it. I have been around those airplanes most of my life and still have trouble getting a mental hold of the structures involved. Aero is no problem but beams and skins, no way it can be done at those sizes.