fineness ratio and yeah I thought that might throw someone off but
actually, you got it anyway.
Cheers
Monroe
-------- Original Message --------
Subject: [AR] Re: Spin stabilized rocket
From: David Summers <dvidsum@xxxxxxxxx>
Date: Mon, December 24, 2018 9:17 am
To: arocket <arocket@xxxxxxxxxxxxx>
"The larger the diameter/fineness the more pronounced it gets."
In this you meant just the fineness ratio, right? Because
diameter/fineness would technically be diameter squared / length?
Just checking that my understanding of the issue isn't backwards!
Thanks!
-David Summers
On Mon, Dec 24, 2018 at 9:45 AM Monroe L. King Jr. <
monroe@xxxxxxxxxxxxxxxxxx> wrote:
If you've got asymmetrical burning that bad not caused by a moon burner
or something like that you've got a problem.
The rocket in question was spinning about 100rpm. Lol and I mean it
looked like a wet noodle! Right at MaxQ. There is video! I'll look for
it.
Of course, you built a stable rocket in the first place right? How much
fuel if any was left in that motor? Where exactly is the CG and CP at
MaxQ?
Because the results look a lot like instability. In fact, this was what
I thought it was at first.
Think polar moment of inertia. The larger the diameter/fineness the more
pronounced it gets.
Monroe
-------- Original Message --------to
Subject: [AR] Re: Spin stabilized rocket
From: David Summers <dvidsum@xxxxxxxxx>
Date: Mon, December 24, 2018 7:02 am
To: arocket <arocket@xxxxxxxxxxxxx>
Any video? ;-)
I'd suppose this is something where you balance it as much as possible,
right? I'd imagine the balance is thrown off during the burn since
propellant doesn't burn perfectly symmetrically, for example.
-David Summers
On Mon, Dec 24, 2018 at 3:04 AM Monroe L. King Jr. <
monroe@xxxxxxxxxxxxxxxxxx> wrote:
It needs to be dynamically balanced if it's 2 stages the first and
second need to be balanced together and the second stage has to balance
on its own. Dynamic not static!
I've seen rockets look like a wet noodle because of spin stabilization
and unbalance. Also very critical at transonic (MaxQ)
Monroe
-------- Original Message --------performance
Subject: [AR] Spin stabilized rocket
From: David Summers <dvidsum@xxxxxxxxx>
Date: Sun, December 23, 2018 2:50 pm
To: arocket <arocket@xxxxxxxxxxxxx>
A quick question for those of you in the know: what is the best
that you can expect from a spin stabilized rocket. Is it conceivable
make it beyond 100 km altitude?
Just trying to see what would be possible to achieve with an unguided
rocket.