Re: OT: Repeatably lobbing "projectiles"

On 11/22/2024 3:35 PM, Jeroen Belleman wrote:

On 11/22/24 23:12, Don Y wrote:

On 11/22/2024 1:21 PM, Jeroen Belleman wrote:

But, to do so completely under automation, without any human
intervention.

>
You may want to look at marble machines on youtube. This one
seems much like what you're asking for.
>
https://www.youtube.com/watch?v=-AZMmg0qq4A

>
While it appears to be repeatable, it is recycling the
same projectile.  And, the same target distance (which
falls considerably short of the 20 ft mentioned in my post)
I.e., one would be surprised if it DIDN'T recapture the
projectile on each execution.

 Surely those are issues within range of your abilities?

Sure -- at the expense of building one and tinkering with
it.  Why invest that time if someone already has experience
with mechanisms that can offer the stated performance?
Why have a newsgroup if limited to discussing your past
accomplishments instead of current design challenges?

You're free to scale and reconfigure the thing. If you
want an exact solution, at least specify your exact
requirements. Otherwise we'll think you're here just to
argue. You know how to state exact specs, don't you?

What specs are missing from my original post?
YOU suggest the projectile (so I don't unduly constrain your
choice of solution).  Note Liz's comment that her choice of
projectile had to be "notched" onto the bowstring.  Is it
fair for me to question how this would impact the automatic
reloading of the gun?
YOU suggest the mechanism (so I don't limit your approach).
I mentioned my initial choice of a compressed spring.  This,
motivated by observing how repeatably a player can launch
a 1" steel ball on a pin table to control where it "falls"
into the playfield.  And, the problems I found with that.
You suggest the materials required (so I don't constrain the
manufacture of said mechanism).  Whether its a leaf spring for
a crossbow or a compressed gas container.
YOU define *how* the range will be controlled.  Clive has
suggested exploring how players "calibrate" their throws in
a ball-tossing game.  (A machine that could play said game
would be more instructive -- esp if it had no feedback
about ITS throws)
You must LOB (not "direct line of fire") the projectile a distance
specified *before* you launch the projectile.
The tough part is being able to do that WITHOUT ADJUSTING
YOUR SETTINGS.  You can't see how THIS launch plays out;
you've had to bake the launcher's characteristics into your
solution.  How you calibrate it (before deployment) is a
separate issue -- and one that I have not placed constraints on,
either!
Otherwise, it would be trivial:  "Hmmm... got to go a bit longer.
Let's tweek the propusive force or the launch angle and try
again".  That's how *most* guns (and shooters) are used,
whether on the shooting range, battlefield or playground.
Note that I've deliberately left anything that has no hard
requirements "open" as negotiable.  Negotiable means I am free
to find fault with issues that your choice may precipitate
(I am surprised that no one has suggested an explosive propulsion
event -- aside from my mention of the lighter fluid propellant;
do you think I *might* object to that?!).
Like any client, I reserve the right to find fault with a proposed
solution -- because there are always other factors that come into
play that one doesn't nail down in a specification, a priori.
Should I rule out a solution ahead of time by limiting
proposals to those that can be manufactured for $X?  Or, that
only use wooden parts?
OTOH, if I need a wire EDM machine to cut a piece of carbide
to meet your design, I'm PROBABLY going to say "no thanks".
If your imagination is so limited that someone has to constrain
every possible degree of freedom, how do you consider yourself
an "engineer" and not just a "technician"?
How do you deal with clients/employers who can't COMPLETELY
constrain your solution before you start work?  You must have
a truly privileged existence if everything is spelled out for you
before you get started; it lets you justify any solution simply
by stating that it "ticks all the boxes"!