Show us your hybrid

Discussions on hybrid rocketry including rockets, motors and technologies.

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Voyager
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Re: Show us your hybrid

Postby Voyager » Sun May 20, 2018 10:41 pm

CATO wrote:One day..... :roll:

Rattworks 29mm H70 & I90 motors and motor kits.....


SNAP! The Rattworks I90 was my first hybrid motor in the Gamma. I had intended to start with the H70 when I first got into hybrids, but they had no stock, so I purchased the I90 instead.

The supply of Rattworks reloads is a little random, hence my move to Contrail.
TRA 14574 L2 (CRG)
AMRS 199 L2 (NSWRA)

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Re: Show us your hybrid

Postby CATO » Mon May 21, 2018 6:53 am

03flyer wrote:
Hey, Cato,
What’s holding you back from going Hybrid?


No offence, 2 things holding me back, knowledge and time.... Both are in short supply....
"In thrust we trust"

AMRS 21 L3 RSO
TRA 07459 L3

Impulse:
2019: 7,898 Ns (54% M)
Ns 18: 14,767; Ns 17: 5,973; 16: 34,558; 15: 35,955; 14: 6,016; 13: 10,208
PB - Gorilla N2717WC, H: 10,260', S: M1.14

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Voyager
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Re: Show us your hybrid

Postby Voyager » Mon May 21, 2018 11:12 am

03flyer wrote:... What’s holding you back from going Hybrid? ...


You probably could have asked me the same question a couple of years ago. You do need the time to get the experience. While I have been primarily a solid motor flyer, I am gradually moving over to being primarily a hybrid motor flyer. The move to HPR hybrid motors for me required a headspace shift and a different level of commitment.

While prepping a hybrid motor (up to installing the fuel grain and ignition grain) is not dissimilar to prepping a solid reloadable motor, that, for me, is where the similarity ends. The practical aspects of hybrids: the extra precautions; the extra GSE; the need to purchase, transport, store and use N2O. Additionally, having to pay rent on a cylinder is also incentive to be committed to the technology.

The fill process requires extra care from the individual and the group. An aborted launch for a hybrid is a little more involved than for a solid motor. The conditions at the launch site also effect the the operation of the hybrid - not just wind. The N2O needs to be maintained within a safe pressure range. Too cold at the site, pressure is too low. Too hot at the site, the pressure is too high. However, this is quite manageable if the appropriate measures are taken.

When you successfully launch your first hybrid, there is no turning back! As with solid motors, if you follow procedures, it will work.
TRA 14574 L2 (CRG)
AMRS 199 L2 (NSWRA)

strud
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Re: Show us your hybrid

Postby strud » Wed May 22, 2019 9:28 am

Hybrids are different in many ways, not all "more betterer"

- lower perceived cost in larger impulse launches (ie consumables, not in support equip etc)
- novel flight differences - longer thrust duration, different sound, lower thrust level at higher impulse etc
- higher complexity - need to bring a lot more gear to the launch, actual launch is more complicated (more to go wrong, more to think about)
- no engine delay ejection ie must have independent recovery control system

Some of the most 'fun' launches I have done were 2 stage with hybrid sustainers that had 10s+ burn times :D Another real crowd pleaser I can remember was TPs at WWW2010*?) that was 'going into orbit' as TP put it.

All that being said, they are interesting and in bigger impulse flights will be the way I proceed mostly.

There does seem to be a limit that commercial motors hit around the M class and indeed not many manufacturers seem to be about for the long haul.

CATO - happy to assist with any questions you have and with GSE etc.

Oh by the way, anyone bought N2O lately? What is it costing nowadays?

strud
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Re: Show us your hybrid

Postby strud » Wed May 22, 2019 9:38 am

Just remembered there are a few videos drew put up of the commercial motors I've flown (rattworks)



Will have to look harder for some others....

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Voyager
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Re: Show us your hybrid

Postby Voyager » Wed May 22, 2019 10:45 pm

strud wrote:
Oh by the way, anyone bought N2O lately? What is it costing nowadays?

Currently it will cost me $217 for my next DE bottle.
TRA 14574 L2 (CRG)
AMRS 199 L2 (NSWRA)

strud
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Re: Show us your hybrid

Postby strud » Wed May 29, 2019 5:15 pm

Hi Voyager

Is that from BOC?

I got a price of $225 + GST about a week ago from them so a bit more than your paying.

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Re: Show us your hybrid

Postby Voyager » Sat Jun 01, 2019 5:15 pm

strud wrote:Hi Voyager

Is that from BOC?

I got a price of $225 + GST about a week ago from them so a bit more than your paying.

Yes. Our local Gas & Gear is a BOC supplier.
TRA 14574 L2 (CRG)
AMRS 199 L2 (NSWRA)

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Re: Show us your hybrid

Postby Voyager » Sat Jun 01, 2019 5:29 pm

Here is my extended Double Shot 2nd stage on a Contrail 38mm 36" motor with a J246-HP grain and medium nozzle at our last HPR launch in April. The flight was with a redundant dual deploy configuration using Altus Metrum EasyMinis. A Featherweight GPS Tracker was installed in the nosecone. The darker mid section is the required extension to accommodate the 36" motor tube. The flights with this configuration have been impressive.

contrail-38mm-J246-hybrid-1-s2.jpg
contrail-38mm-J246-hybrid-1-s2.jpg (145.5 KiB) Viewed 99 times
TRA 14574 L2 (CRG)
AMRS 199 L2 (NSWRA)


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