|I've been interested in this particular aircraft tail design recently. However, it seems that I can't find much information about them. In Daniel P. Raymer's book "Aircraft Design: A Conceptual Approach", there is the following short passage about them:
The "back-porch" or "aft-strake" is a horizontal control surface that is incorporated into a faired extension of the wing or fuselage. This device, seen on the X-29, is mostly used to prevent pitchup but can also serve as a primary pitch control surface in some cases.
The only two aircraft I can think of at the moment with aft-strakes are the X-29 and MiG 1.44. With these aircraft, they seem to be secondary control surfaces with the canards playing the primary role for pitch control. Dr. Raymer seems to be suggesting that there are aircraft that use them as the primary pitching surfaces. Would anyone here know of any such aircraft? Even if they are unbuilt projects?
Also, I'm wondering what the relative advantages and disadvantages of aft-strakes are (without canards)? I can possibly see them as being less draggy and stealthier than a conventional, all-moving tail since it doesn't have a leading edge (since it blends into the rear of the wing). It might also serve as a place to store extra fuel (I believe I once heard that extra fuel is stored in the strakes of some upgraded variant of the MiG-29). I see a potential disadvantage in pitch authority versus conventional stabilators, however, particularly at high angles of attack.
I do kind of wonder why they aren't seen more often.