[SS2S-Main] Re: Successful Rosetta launch

  • From: Richard Nakka <richard.rocketry@xxxxxxxxx>
  • To: sugarshot@xxxxxxxxxxxxx
  • Date: Wed, 17 Dec 2014 11:39:57 -0600

OK, somehow I thought Flint's 'specialty' was nozzleless motors. I
must have missed the caseless project :-\


On Wed, Dec 17, 2014 at 10:49 AM, Redacted sender monsieurboo@xxxxxxx
for DMARC <dmarc-noreply@xxxxxxxxxxxxx> wrote:
> IIRC Flint's caseless motors were a sugpro project and have flown
> successfully.  If I can find the history in my archives I'll pass it along.
> Cheers,
> Mark L.
> -----Original Message-----
> From: Richard Nakka <richard.rocketry@xxxxxxxxx>
> To: sugarshot <sugarshot@xxxxxxxxxxxxx>
> Sent: Wed, Dec 17, 2014 11:44 am
> Subject: [SS2S-Main] Re: Successful Rosetta launch
> 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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