Building Tips and technical articles. > ARF'S
ARF SV11 incidence check.
Manuel Cortes:
Hi all.
I am in the assembling process of a Brodak ARF SV11. Before epoxy mix I have check the engine-wing-stab incidence and have discovered that he engine trust line performs a -1,6º (negative, downtrust incidence).
It is obvious than every Brodak ARF-ARC SV11 reviewed here performed very well, so I suspect a eventual unit defect, but I want to know if any of you had checked the incidence and your results.
By the way, I will shim the alu pads for a 0-0 trustline adjust before assembling the model.
Thanks for your time and kind regards from Spain.
Manuel.
P.S. The weight is excellent, expecting 58-60 oz with a T&L ST60.
Dan McEntee:
I would not change that down thrust. If you are a PAMPA member, go through the back issues for an article by Bob Whitely titled "Things That Always Work" and in that article he points out always building in about 1 degree of down thrust, 1 degree of right thrust, and 1 degree of positive incidence in the horizontal stab. These are all to offset forces form the prop and engine and every model I have flown since reading that article has been set up that way. With the ST.60 and the pitch that is usually used with that engine, I think that you will want these adjustments and like them. With these setting and other basic bench trimming techniques I usually get a model that tracks well enough to fly the pattern from the first flights.
Type at you later,
Dan McEntee
John A Miller:
I most totally agree with Dan. Leave the engine engine down thrust alone. My results using Bob Whitley's suggestions from his article, "Things that always work', have mirrored Dan's results.
The numbers I use are, 1 -2 degrees down thrust (for a counter clockwise turning prop). Just enough out thrust so you are sure there is no in thrust, and Positive stab incidence. According to Dave Fitzgerald's writings on the subject,, this positive incidence can be achieved by raising the stab leading edge by placing a narrow strip of 1/64" plywood under the stab leading edge.
Good Luck and HAPPY FLIGHTS
John Miller
Manuel Cortes:
Thanks very much for your words, guys, deeply appreciated.
Kind regards from Spain.
Manuel.
Kind Regards.
Manuel Cortés.
Doug Moisuk:
I would check with the designer Randy Smith. He also had a lot to do with the production of the kits.
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