Originally posted by Andy Turits
Okay so all you guys who were involved in my mach 10 vs. falcon pileup...I've got a specific question about the Falcon for those of you who have built it and or may have one for reference.
I posted some Astron Falcon tips on RMR. I'm summarizing them and reposting them here for consideration.
(a) You need some difference between the angles of attack between the stab and the wing to get this bird to glide.
I originally took to putting a small wedge under the trailing edge of the stab to force this angle into place. If this wasn't done JUST precisely right, the bird would glide great, but loop into the ground under power.
The secret to getting good Estes Falcon performance is to put the incidence in the WING. (I stole this idea shamelessly from Kevin Stumpe, husband of NAR HQ manager Marie Stumpe.) He suggested 2-3 degrees of incidence in the wing to me during one of my NAR HQ visits. Putting the incidence there means it's close to the boost CG, and will thus have less of a moment arm to work through during boost.
As soon as the engine spits, then the CG shifts, and the moment arm gets a lot longer, and more effective. Instant pull-out from a dive.
How to get that angle in there, you ask?
You could try eyeballing it, but I prefer to cut a couple of small balsa triangles to the 2 degree angle, glue them first to the fuselage, then glue the wings in place using the triangles as a guide.
You just need a rectangle of 1/16" balsa as long as the root edge of the wing.
Now split the rectangle into two triangles, by measuring a 2-3 degree angle and cutting it on that diagonal.
Build the Falcon fuselague stock.
Now take the triangle, and glue the straight edge of one of your triangles such that the 2-3 deg. angle is located at the wing glue location.
Glue wings in place, and voila!
When I used this trick on my Canon City NARAM Falcon, it worked perfectly for 6th place in teams. Not bad for a 30+ year old design whacked together in less than 2 days.
(b) Introduce some roll on boost.
I do this by canting the pod a bit to one side.
DON'T overdo it.
To get the alignment right, I center a 1/8" dowel in an expended engine casing, insert that into the body tube, and then align the tube on the pylon such that the thrust line is about 1" to the right of center at the trailing edge of the stab. If you more than 1", the model expends too much energy spinning and won't get any altitude. In retrospect, I think you can get by with less, say maybe 1/2".