Scott,

I just stumbled onto your A-4 post and thought I would comment.

The A-4 is commonly called a double delta, but has absolutely no flight characteristics common to a conventional delta wing. Remember that a delta wing airplane has no tail!

Does the airplane sit on the ground with the nose high or is it level like a pattern airplane? It should sit with the nose high in order to rotate rather than respond abruptly to too much elevator throw. What is your elevator throw? It should be no more than 1/4" on low rates; ailerons should be at or just less than 1/4" on low rates.

On takeoff, it sounds as though you are killing your forward airspeed due to an abrupt change in AOA; the airplane loses lift and stalls. You may also have positive incidence in the stab, causing the wheelbarrow effect. You would be better off to get rid of the spongy nose gear and make it rigid. You'll continue to fight steering control as well as incidence as long as the nose gear is springy.

Best regards,
Larry Wolfe
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