It passed spin test. Appeared stable under initial boost and lost it at about 50% burn. Will conduct wind tunnel tests on V2.0
Space Ark, The return
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lakeroadster
When in doubt... build hell-for-stout!
I've seen this happen on a number of my oddrocs (Cygnus Probe & Mercury LES). Very stable while under thrust, but AoA during the coast phase.
They then don't reach enough altitude to properly deploy the recovery device such that the chute billows and slows the rocket properly.
I dunno, to me that looked like it was arcing over hard right from the get-go. Marginally stable at best, IMHO.
lakeroadster
When in doubt... build hell-for-stout!
Opinions vary... It's flying stable, it just looks to me like it's weathercocking. The bigger the fins the bigger the weathercocking. Which makes sense with those huge wings. It wants to fly into the wind... and it did if you look at the flag.
Another question, Is that big rear horizontal stabilizer level with the fuselage c/l?
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It was
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My experience with weathercocking is that it initially kicks in just off The pad on overstable rockets that haven’t got up to full velocity, so it is a factor not just off CG/CP being too far off, it also insuffic velocity prior to departing the rod or rail guidance. The rocket tips over, but as it picks up speed it eventually straightens out (unfortunate by the time it straightens out it is off vertical and sometimes fully horizontal, the so called ”cruise missile“. it may continue to Weathercock (arc over) more and more, but the arcing becomes less and less as it picks up speed. @lakeroadster ’s experience may be with barely stable draggy rockets which are borderline under thrust, but have so much drag that as soon. As they hit coast phase the airflow is insufficient for the fins to function.
we tend to think of the swing test as the gold standard, but even the swing test requires a certain velocity to get the airflow sufficient for fin effectiveness.
another factor people may not consider is launch lug/rod drag or rail button/rail drag. On a windy day (where the rocket may be slightly torqued and the front and rear edges of the lug scrunched into the rod) or with a rod sticking with exhaust residue or a launch lug with paint inside, the drag may significantly reduce velocity to the point that it is significantly less than sim value predictions. The wind issue is one reason some of my Rockets use two lugs, one at or forward of the CG, and one at the tail. The pair Causes less wind torque on the rod into the rocket gets moving, the rest lug gives me a more effective rod length.
we tend to think of the swing test as the gold standard, but even the swing test requires a certain velocity to get the airflow sufficient for fin effectiveness.
another factor people may not consider is launch lug/rod drag or rail button/rail drag. On a windy day (where the rocket may be slightly torqued and the front and rear edges of the lug scrunched into the rod) or with a rod sticking with exhaust residue or a launch lug with paint inside, the drag may significantly reduce velocity to the point that it is significantly less than sim value predictions. The wind issue is one reason some of my Rockets use two lugs, one at or forward of the CG, and one at the tail. The pair Causes less wind torque on the rod into the rocket gets moving, the rest lug gives me a more effective rod length.
Just means lots more work to be done on v2.0
lakeroadster
When in doubt... build hell-for-stout!
.... and if the data during the swing test is documented (a video of the test):
- length of string from hand to rocket
- No. of Revolution in a given amount of seconds
Launch Rod? We don't need no stinkin' Launch Rod
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Moved it for ya. If that's not ok, I'll delete it, ; )
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not if your have gimballed motors!
I've been trying to decide which is closer to my skill set: gimbled motor or RC control surfaces.
lakeroadster
When in doubt... build hell-for-stout!
Witchcraft!
lakeroadster
When in doubt... build hell-for-stout!
I don't think the Redstone had a gimballed motor? It did have rudders and carbon jet vanes, however.... so, point taken.
"The tail unit consisted of a riveted aluminum structure with four stabilizing fins and air rudders with carbon jet vanes extending into the exhaust stream"
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PayLoad
I don't do spirals
Beautiful rocket, but it would have made the same flight if there were no wind at all. Sim it, you will find it is just unstable in design.
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The V2 is how I started. I have the dimensions to my son who created them.
Probably easier
Been looking at the Estes Antar kit , if you mod it slightly by adding wing tip nacelles and some small tubing under wings for the engines then spray silver with a nice clear coat , its pretty similar to the movie space ark , plus it will be stable as it’s mostly a standard kit .
