> >I am curious about the effect of wingloading on aerobatic
> >potential. For instance, consider two CGM Extras, one powered
> >with a .61 2-stroke and weighing about 7 pounds and one powered
> >with a 1.2 4-stroke and weighing about 10 pounds. Assuming all
> >other things are equal (CG, surface throw, etc.), which plane
> >will have better aerobatic capabilities? Of course, the 1.2
> >version will have superior vertical performance, but aside from
> >this, will one or the other be any better? It's pretty clear
> >the lighter version will have a lower stall speed and probably
> >land easier. Will it also respond faster to control inputs
> >because of less inertia and momemtum? Will the heavier version
> >perform better snap maneuvers because of the higher stall
> >speed? I would love to hear anyone's thoughts on this.
Well...... maybe I can offer sump'tin here.........
I do a fair amount of test flying of new planes, and I'm often asked
to "Debug" some aircraft.... - I have had the opportunity to fly several
Ultimates, which , as many of you now know, need some "tweaking" to
become good aerobatic machines...
Three stand out in my memory....
A - STRONG OS 61, 7-3/4 lbs,
Run out of steam at 250 ft vertical, glided well,
tight manouvers, tumbled well, was the MOST PURE FUN to fly. Light and
B - ST 90 ring, 8-1/4 lbs,
Vertical till I said stop, handled about the same as (A)
nor quite as agile, glided well, wind penetration a little better (had wheel pants
-A- did not)-------
(this is my own aircraft)
C - YS 1.2 10 - 1/4 lbs,
Vertical was BALLISTIC ! but........ it had the glide of a
cinder block, - dead stick was a panic with the weight penalty and the drag of
2 wings, struts etc. - snaps were too good, like - at the bottom of square loops
etc. :) Did everything required (like knife edge loops) but could bite, - the
owner had trouble with the landing gear bending - prolly due to the wt and
stalling a little to soon on landings that were much faster than (A) above.
Wind penetration was very good,( wasn't bounced around by the wind)
Another observation... The life span of the Goldberg Ultimate
appears to be inversely proportional to the increase in weight of the aircraft....
FWIW, (A) was the most fun to fly (unless you hafta rocket vertical
ALL the time), (B) is fun and I'm happy with it, (C) was a rocket and provided
a special kind of fun but required an expirenced pilot to keep alive and a VERY
reliable eng. (I hear he later added a glow driver)
Cheers ! ...... Dave