Why not hybrids?

DRAGON64 said:

I made some inquiries over the last week and a half, and have managed to draw out some old SkyRipper hardware and reloads. I will be receiving 29mm; 38mm and 54mm hardware and reloads over the couse of a week. Today the first loads showed up; I had been talking with Doug Pratt of Pratt-Hobbies about getting his GSE, and thought I would ask if he had any old stock of SkyRipper relaods... he did, and they arrived today (1) package ea of the polypro and PVC 38mm reloads and (3) packs of the 54mm reloads:

I have more 54mm, 38mm and a few 29mm reloads coming as well, plus the 3-complete systems that Todd developed over the years... I should be set for flights for a while.

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Johnny, you dog you! (Great find :drool

But hey, when you are ready to sell out, just let me know and I'll take another trip down to Huntsville .

DRAGON64 said:

My plan is to start silicone molding the reloads that are injected molded, so I can make my own reloads over time. More on that as I research more on the molding process and the plastics available, like polyurethane etc.

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I plan to go the Research path also.

dixontj93060 said:

Johnny, you dog you! (Great find :drool

But hey, when you are ready to sell out, just let me know and I'll take another trip down to Huntsville .



I plan to go the Research path also.

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These are sweet reloads, I really wish that Todd was still in business for us.

I found 3 sets of reloads left for my 54mm Skyripper, already have reload tubes to 'try some stuff out' afterh the reloads are gone.

I plan to fly a BUNCH of hybrids at the November ROC launch, the plan is to do a RATT H, RATT I, RATT J, Skyripper K, RATT L, and a Contrail M.

'The Boy' wants to try launching a Night Hybrid. Might have to give that a try.

Not sure if anyone else will be out at ROC in November launching Hybrids, let me know.

Mike K

Launch a contrail K sparky at night.... just imagine... check the video from the Kramer X4 using the Contrail Hybrid 54mm with fast nozzle (3 injectors) with the sparky fuel... 40 pounds at start reaching 2400ft... and lots of sparks... start at 0:30".. NEW video and foto by my friend Piero Valle from the Italian Rocketry Association 2 weeks ago. His copyright.



[video=youtube_share;Mwnad6oqM-Y]https://youtu.be/Mwnad6oqM-Y?list=UU9SK4AOnovxW8H_dwyk-ksw[/video]

legranddudu said:

Launch a contrail K sparky at night.... just imagine... check the video from the Kramer using the Contrail Hybrid 54mm with fast nozzle (3 injectors) with the sparky fuel... 40 pounds at 2400ft... and lots of sparks... start at 0:30".. video and foto by my friend Piero Valle from the Italian Rocketry Association 2 weeks ago. His copyright.

[video=youtube_share;Mwnad6oqM-Y]https://youtu.be/Mwnad6oqM-Y?list=UU9SK4AOnovxW8H_dwyk-ksw[/video]

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Denis, you are the undisputed Contrail King!

legranddudu said:

Launch a contrail K sparky at night.... just imagine... check the video from the Kramer X4 using the Contrail Hybrid 54mm with fast nozzle (3 injectors) with the sparky fuel... 40 pounds at start reaching 2400ft... and lots of sparks... start at 0:30".. NEW video and foto by my friend Piero Valle from the Italian Rocketry Association 2 weeks ago. His copyright.

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That rocket has more stability than most of my 3FNC's. Love the sparky on that flight too.

well, let me entertain you: the rocket weights approx 20 kilos on the ramp. 2 kilos are the motor with reload and gaz fill. goes thru the rocket length to the vers top, neutral from a cg point of view, well nearly rofl..

18 kilos the net rocket. the nose cone weights...9 kgs!. half of the rocket weight in the nc. shall fly stable and does. by the way i came to the point as my sources in bmw told me the real one was same ratio. TnT, not lead in the nc lol.....


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Hey John,

I'm not Denis but what I did this weekend was come out of one spot so all three were visible at the same time. The flight was early enough in the day the humidity was still up and all three were distinct plumes with the naked eye at 150m. I also use a wireless camera system to watch the vent streams. Nice views no matter how far out the rocket is. I'll post flight details in the cluster thread when I get the chance.



Jason

jderimig said:

Dennis, I have a question for you. On your 3 motor cluster flights, how to you tell if all three motors are full? Do you bring your vent tubes to one side of the rocket so you can see them all at one view?

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John, I put my vent tubes 90° from where I stand. Works fine with a 2 motor cluster. I can control 2 plumes and take decision to start.
On the 3 motors cluster I use a friend that stands same distance at 90° from me, so he can see the 3rd plume, which is in my direction. We communicate optically ("hand up") and I start..very simple...

jderimig said:

Dennis, I have a question for you. On your 3 motor cluster flights, how to you tell if all three motors are full? Do you bring your vent tubes to one side of the rocket so you can see them all at one view?

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THANKS ALOT GUYS!!!! I have been keeping up with this thread and I found a deal on a Rattworks I motor, so I had to pull the trigger and buy (will be picked up for me at MWP.
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
[email protected]
www.countylinehobbies.com

Thanks Denis and Jason for the venting reply's. I hope to join the club at LDRS34 (or maybe NYPOWER next year).

bob jablonski said:

THANKS ALOT GUYS!!!! I have been keeping up with this thread and I found a deal on a Rattworks I motor, so I had to pull the trigger and buy (will be picked up for me at MWP.
Mr. Bob
Countyline Hobbies
Grovertown, IN.
574-540-1123
[email protected]
www.countylinehobbies.com

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I loved the RattWorks I80 motor... nice semi-long burn 29mm hybrid.

My motors arrived yesterday, and today I managed a little time to assess what I have... everything but the 54mm system is used; the longer 29mm case has been over pressured at one time. Looking at the pic, you can see the shiney rim where the case was ground to remove from the motor mount. The nozzle is also fractured pretty good. I ewill need to have another nozzle cut. One of the 38mm case, the middle one, has taken a nasty tumble sometime ago, and the deformity was gound down to fit the reload components. It should still work okay... but the 29mm case will need to be shortened & replaced as I will not be able to fly a cut case at a commercial launch.



More clean up work to be done, and these motors will be readyfor the winter flying season.



Over-all I am happy with the gathering... I am still waiting on a couple more reloads to arrive.

I've had a case "bell out" a bit as well but it was from an overly aggressive ejection charge not an over pressure. Recovery harness hooked to the forward closure. Yup, it was a whoops! Big charge, short cord.....

Jason

Some hybrid related pictures from the Bologna Launch...Just funny...this is real sport...hybrid ramps are typically at Level 3 distance from the crowd...so you need to walk, and walk and walk...and push!

And when it comes to the second of the start, after filling the tank, you feel really lonely...you are in fact...you are far away from the crowd...and far away from the rocket...you stop filling and your thumb activates the red button... lonely rocket cowboy...

All pictures above copyright Federico Barattini ([email protected]), a professional Italian Fotografer... he understands also rocket erotic *lol*

legranddudu said:

And when it comes to the second of the start, after filling the tank, you feel really lonely...you are in fact...you are far away from the crowd...and far away from the rocket...you stop filling and your thumb activates the red button... lonely rocket cowboy...

View attachment 188243

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Like describing a golf swing or putt... nice image; is that an airport you guys are flying next to? The filed looks fantastic, thanks for sharing the pics.

jason-and-his-toys said:

I've had a case "bell out" a bit as well but it was from an overly aggressive ejection charge not an over pressure. Recovery harness hooked to the forward closure. Yup, it was a whoops! Big charge, short cord.....

Jason

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I looked the case over, and you may be right... this could very well be a hard ejection pull on a forward bulkhead mounted eyelet.

It is difficult for a hybrid to overpressurize at the nozzle end. The small cases have a very large safety factor. The combustion pressure is likely somewhere near 400psi. The nitrous pressure in the tank is only a few hundred psi greater than this... So if combustion pressure spiked over, say, 900psi, then flow would reverse and hot gasses would be blown back into the nitrous tank. This would be bad. How bad depends on the purity of the nitrous and the diameter of the tank, and the pressure. But it would have the potential to turn the tank portion into confetti when the nitrous load goes monoprop in the confined area with only the injectors for venting.

Gerald

G_T said:

But it would have the potential to turn the tank portion into confetti when the nitrous load goes monoprop in the confined area with only the injectors for venting.

Gerald

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Actually I have that happen, it turns the case into a nice shovel with the combustion chamber end being the handle.

G_T said:

It is difficult for a hybrid to overpressurize at the nozzle end. The small cases have a very large safety factor. The combustion pressure is likely somewhere near 400psi. The nitrous pressure in the tank is only a few hundred psi greater than this... So if combustion pressure spiked over, say, 900psi, then flow would reverse and hot gasses would be blown back into the nitrous tank. This would be bad. How bad depends on the purity of the nitrous and the diameter of the tank, and the pressure. But it would have the potential to turn the tank portion into confetti when the nitrous load goes monoprop in the confined area with only the injectors for venting.

Gerald

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jderimig said:

Actually I have that happen, it turns the case into a nice shovel with the combustion chamber end being the handle.

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The case was damaged enough, that I believe nitrous pressure would blow the top ring out, so I have purchased the 29mm SkyRipper set that has been for sale here on the forum... This also takes care of the damaged nozzle I received with the first set.

The case damage does in fact look like hard ejection failure. These bulkheads are designed to take on an eyelet, and there was probably a pretty hard event that nearly pulled the bulkhead from the motor. Luckily, the case can be shortened to the next size case in the system, and then I could maybe tinker with small scale hybrid clustering...

So this is what the three vents looked like from 150m. This flight was fairly early in the morning so there was still lots of humidity. A HyperTEK flight I did later in the day didn't have a nice vent like this did.

Photo credit to John Moore.

Jason

jderimig said:

Thanks Denis and Jason for the venting reply's. I hope to join the club at LDRS34 (or maybe NYPOWER next year).

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Cool, thanks!

Jason this is fantastic, congratulations!!!


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Hi guys, I fly Hypertek and use Davey Fire type igniters with slow burn an 02, on M's I use 2 igniters to be on the safe side and avoid wasting the NOS. Never fails.

I thought some of you non rocket scientists may find this interesting [video=youtube;o9erCLJ5KVg]https://www.youtube.com/watch?v=o9erCLJ5KVg[/video]

Playing around with SolidWorks, I modeled up one of the 29mm SkyRipper grains. I will be sending the files to a couple individuals who have 3D printing capabilities. Hopefully a material that is an ABS derivitive could be used to make fuel grains for research use. Below is a simple cut away view of the fuel grain.

DRAGON64 said:

Playing around with SolidWorks, I modeled up one of the 29mm SkyRipper grains. I will be sending the files to a couple individuals who have 3D printing capabilities. Hopefully a material that is an ABS derivitive could be used to make fuel grains for research use. Below is a simple cut away view of the fuel grain.

View attachment 245843

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Great idea! Do you plan on doing this for the 38mm and 54mm also?

dixontj93060 said:

Great idea! Do you plan on doing this for the 38mm and 54mm also?

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Yes, especially the 54mm with its unique "bates" style configuration. As for the 38mm; these can be cut from PVC pipe, but 3D prints of the fuel grain opens up opportunities of fuel grain geometries not realized from pvc pipe milling... the 3D printing process will offer the same opportunities for all the sizes.