[SS2S-Main] Re: Successful Rosetta launch
- From: Richard Nakka <richard.rocketry@xxxxxxxxx>
- To: sugarshot@xxxxxxxxxxxxx
- Date: Wed, 17 Dec 2014 10:43:52 -0600
Thanks for posting the update on your work, Flint, and congratulation
on the successful Rosetta flight. If I understand correctly, your
motor was a core burner, with cast-in-place propellant?
Your proposed "tubeless" rocket motor sounds cool, it'd certainly be
interesting to hear how that turns out.
cheers,
Richard
On Mon, Dec 15, 2014 at 2:22 AM, flint hapirat
<dmarc-noreply@xxxxxxxxxxxxx> wrote:
> Hi All,
> Had a launch (after 2+ years!) last week.
> Apart from the regular spin burner (nice! - I'm still in love with those
> Jimmy!!!!) and nozzless "regular" KNSB motors, it was a first successful
> Rosetta launch.
> The Rosetta flight was very pleasing - using a single ematch all 3 cores
> ignited instantly and the motor took off but reached a fairly low apogee
> (not measured).
> Longer cores will be used next time to have it reach a higher apogee. Also,
> a larger mold for these motors will be used (approx 50mm OD, with 7 cores)
> I did take a video but except for the initial launch, the liftoff sound and
> a bright reddish-yellow spot in the sky you don't see much... so I'll skip
> it.
> So far it's the heaviest motor I've ever made to lift off the pad - approx
> 200gr (yes, I know it's peanuts to most of you guys... but remember where I
> live... restrictions and all that).
>
> Specs below in case you are interested -
> The Rosetta grain had 3 cores 4mm OD, 110mm long each, it was 30mm OD total
> and 150mm tall. A 5mm thick cardboard tube was used as a body.
> The propellant was Serge's KN-NaN-Sb (sorbitol) with 1% RIO and was molten
> at 220c, and poured easily into the mold.
> The mold was filled up to the top of the core rods and a cardboard hemi was
> placed over the cores - forming a void above the cores, thus connecting
> them.
> Once the fuel cooled a bit the motor was filled again to the end of the
> cardboard tube thus forming the plug at the top of the motor.
> The grain was ignited using a single e-match that is 155mm long. Prior to
> ignition a small amount of BP grit (can't recall the mesh size) mixed a
> small amount of with fine Mg grit (roughly 1:10 Mg:BP). The same mix was
> used for the e-match (mixed, added to the ematches and finished during
> launch - not stored!!).
>
> For the next motor a triangular connection of all the core rod tips will be
> done using quick match. This will allow me to pour the KNS and fill the
> entire motor tube in one go. This will also provide a stronger structure
> (not weakened by the dome structure I've used this time. Also, the next
> motor will be tube-less (i.e. no nozzle, no tube, no cap - just a solid
> propellant grain).
> As a side note I'll add I'm also thinking of adding a pre-cast grain of
> KNS-Ti to this motor so the video will show something more interesting than
> a tiny red spot in the sky.
> If all goes well and there is an interest in this project - I'll post a
> report.
> Hope you guys find this interesting/useful...
> Cheers,
> Flint
> http://www.pyrosystems.com/flint/
>
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