double delta (diamond shaped) for 6400 brick or similar ultra-micro equipment. 16" ws, 192 sq in, 50 gr auw.
8mm brushed motor and 5.1" prop from 9 eagles; 1x160 cell. quick release for prop (kind of prop saver). prop is similar to hh's.
the idea is to have a compact, simple, light weight and maneurable airplane, with the shortest wingspan and largest area. diamond shape gets more area than the regular delta, with same span.
1st version is flat planform (no dihedral).
styrofoam is 3mm main and keel, 2mm elevons, 1mm front top and fin, .8mm cf pushrods.
elevons have air dams to channel air so it does not drift towards the center.
the keel serves several purposes: aerodynamically it provides directional stability, acting as an underfin. structurally it is the backbone that gives rigidity and links the front to the back. it also helps to launch it and protects it at landing. it is 1 of the factors that contributes to the stability of the plane. the others are the fin (vertical stabilizer), sweep back leading edge, step, and air dams.
second version has dihedral to add stability, a further forward cg, and a regular hh gearbox and 5.1 prop and rubber spinner.
the idea is to compare for stability and maneurability. later added a small stab.
got some short videos:
https://www.rcgroups.com/forums/show....php?t=1628809
see more details on comments...Continue Reading

what really are backyard models?and park models? when i came back to modelling in 2006 i was shocked with the new technology, and i subscribed to all magazines and began pestering all the editors with questions, among them these. to my surprise, the answers i got were not conclusive.
what i have learned is: 1st, the words used to define a backyard. what is a backyard? what size? usually launching (or taking-off) from your driveway and then flying on the street is considered backyard flying. or if your backyard is really large enough to allow planes like the horizon's ultra-micros fly without hitting something. perhaps about the size of a gym could qualify as the size of a backyard.
then park flyers. what size models can fly in a park? meaning, a baseball park. i think that was the original concept of the word 'park'. the models i consider 'park size' are about 24 to 40" wingspan. but about all, lightweight models that fly slow (like trainers, high wing). very much like my planes: talisman (24"ws, 140gr auw); tramontano (30"ws, 240 gr auw). anyway, that's my perception of the issue. regards