Not mine, the rocket's!
I am attempting to add a payload bay to an existing rocket which will
make the fin area far more than necesarry for the particular rocket.
Since the biggest problem with 'overstable' is it's vulnerability to
weathercocking, if I cut the bulk of the fins out leaving only say 5/8"
on each outside chord and 3/4" along the root would that theoretically
take care of the 'overstable' attitude? The wind should blow right
through the fins and affect it minimally. Theoretically.
He is talking about cutting "lightening holes"... not trimming down the
Does VCP have the capability to handle this kind of modification? I have
never used it, as I have both RockSim and SpaceCAD, so I don't know it's
capabilities... but my guess is that VCP probably wasn't designed for that
level of complexity... am I wrong?
I too am interested in the effect of lightening holes through the fins. I
know Randall Redd is plenty well known for some of his custom creations, and
has made plenty which have center-cut-out style (lightening hole) fins...
maybe you could try to get ahold of him?
Also, RockSim seems to be able to model it if you draw a "custom fin set",
and connect the dots by drawing the root chord first, and then plot around
the outside fin area. I tried it just now on a 29mm G80-10 simulation. For
these example pictures, see (watch for URL wrapping):
Simulation flight seems to be stable and good, although I expect I lose a
bit of altitude by having a greater forward surface area causing slightly
more drag, vice just using smaller fins... I dunno... when I tried it in
RockSim, it actually shows *less* altitude with smaller solid fin of same
weight/total surface area... very odd... not to mention it was calculated to
be slightly less stable... something here doesn't seem to add up...
Absolutely correct! I'm looking at 'holing out' the fins to remove
material which would promote smaller lateral force windcocking. The
outline will remain the same as far as vertical flight, but wind shear
should be minimial......yes? No?
The sims haven't been so kind to those of us in the Mac world......my
latest version of Virtual PC is too long in the tooth to keep messing
with......I need either a mathamatical answer which I can confirm
myself, or a Mac program w hich will reinforce the common sense
idea..........soon I will go to 'seat of the pants' rocket
design........it could be worse.... :-P
What could be worse than using a Mac? >;-)
NAR 71503 Level II
God Bless our peacekeepers
So true, so true.....we've threatened to cut the bridges into Joisey and
let it float away! :-) , we're looking for seafront property.........I
thought of something worse than being a Mac user!! Getting a flat in
the old Ferarri! Getting Brie dropped into your caviar! Not making the
minimum food payment at the county club.....ah yes, there are things
which are worse than being a Mac user, but just marginally.