Questions:
Do the horizontal stabilizers mount to each other and then sit on top of the boom or are they mounted directly to the boom?
Are the horizontal stabilizers given a dihedral (how much) or do they stay flat?
Do I understand correctly that the airfoil on the horizontals stabs is supposed to push the tail down?
Yes, but normally I would cut them out as a single part. The convention of only showing half the stab on plans is to save space. The stab gets glued to the underside of the boom, so you have a nice flat face to glue to.
No. They are flat.
You put the high point on the bottom so the low pressure caused by the airflow over it pulls the tail down, raising the nose. (see post #8 and the other posts about not permanently gluing it on untill you test glide and get the incidence right)
kj
The stabilizers are already cut. I have 3 pieces: 2 horizontal and one vertical. Should I recut the horizontals?
Also, what is the preferred method to temporarily mount them?
Like Nienest on these, I would glue the pod and wings/rudder in place and then fine tune the amount of negative incidence on the stab by rubber banding it in place for the hand tosses. You want a slightly nose heavy glide on these and not a glide that "mushes" or is on the verge of a stall. Start with a few degrees of negative incidence on the stab and work out from there by sanding in additional if needed to get a glide slope you like. Note that the whole stab was at a negative angle and not just the aft elevator part of the TE.
Kevin K.
Mox nix. If you want to, recut it. If you don't, glue them together but make sure the completed stab is perfectly flat.
From post #28...
kj
From post #28...
kj
Back on this thread...
First you glue the rudder to the stab. And I agree with Kevin that the stab should be one piece with the balsa grain going length wise thru the stab.
Next, sand in some negative incidence into the rear of the spruce boom and attach the stab/rudder combo using a rubber band. See attached.
Test glide with everything in place including spent motor casing for a flat glide. If the glide is a bit nose heavy, add more negative incidence or angle.
Last, I would also glue in spruce reinforcements at the LE of the wing where it meets the spruce (or in your case bass wood) doubler on the hinge assembly. Need to make sure that hard material meets hard material when they snap into place.
Later Nienest designs as well as my own used the end grain balsa of the wing itself as the stopper. And the wing stop was the spruce boom itself.
KK
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