Why not hybrids?

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DRAGON64 said:
Back about 2005 I witnessed my first paraffin hybrid flight; a local hybrid guy coverted an Aerotech case to use hor hybrids, and topped it with a 440cc tank. The design was a fill at the flightline and carry to the pad. He shocked us all with his instant ignition design. It was the most beautiful hybrid flight I had ever seen at a research launch. He and I managed to hook up, and he helped me design a 76mm paraffin hybrid. We managed one test firing before our friendship disolved, and here is the video from that one and only session... note that there is no warm up to ignition, when he pushed the button, the motor was ON! The sound to the video was lost, just know that this motor was loud as heck.

https://www.youtube.com/watch?v=ysbdzi3c-9Y
Click to expand...

Wow Johnnie, that is sweet!

Can you explain/comment on the instant ignition?
 
dixontj93060 said:
Wow Johnnie, that is sweet!

Can you explain/comment on the instant ignition?
Click to expand...

An Estes 1/2A was used, minus the ejection charge and paper motor case. The grain would hold a ball bearing in place; As the grain burned, it released the ball bearing from its seal thus dumping the nitrous, all while pre-heating the chamber in an instant ignition sequence. It is touched on and drawn up in Bill Colburn's manual. I have been designing up a similar sequence injector in SolidWorks that will work for a 98mm motor.
 
So I have some Skyripper and Contrail 54mm motor hardware. So if I was to cast some paraffin grains would the current port size (1/4 or 3/8 compression fittings) and nozzle sizes be in the right ballpark?
 
Very nice!

A comment:
Im surprised you got such a long burn time from paraffin.

A question:
Do you have an opinion why the ignition transient was so nice?? Do you think this is due to the use of paraffin, or other issues like running high pressure with a big pre-heater, or something totally different??

-->MCS

.
 
jderimig said:
So I have some Skyripper and Contrail 54mm motor hardware. So if I was to cast some paraffin grains would the current port size (1/4 or 3/8 compression fittings) and nozzle sizes be in the right ballpark?
Click to expand...

Using Todd's hybrid design program would go along way to aid in determining this... Simulating is best.

MCS said:
Very nice!

A comment:
Im surprised you got such a long burn time from paraffin.

A question:
Do you have an opinion why the ignition transient was so nice?? Do you think this is due to the use of paraffin, or other issues like running high pressure with a big pre-heater, or something totally different??

-->MCS

.
Click to expand...

Even after such a long burn, there was still less than half of the fuel grain left, once the melting stopped dripping out of the nozzle. The ignition sequence is rather elegant, I have seen it work many times. Part of the squence required that the nitrous be atomized; Instead of the nitrous being injected straight down the core of the grain, it was injected sideways (radially) into a graphite collar, where the liquid was broke down into more of a vapor state... with the Estes grain burning down the core at igntion, the atomized nitrous comes to life instantly. Sure wish we had a nice hybrid forum, much like this layout, that we could use to share & discuss the particulars abroad.
 
A few additional comments.

1.) N2O contains 33% O versus 100% O in O2. The linear burn rate of a hybrid on nitrous oxide is 3 times slower than liquid oxygen all else being equal simply because oxygen is the reactive species. To make a nitrous hybrid approximately equal to a liquid oxygen hybrid or a LOX/kerosene liquid system, you have to increase the surface area of the nitrous fuel grain and increase the nitrous flow rate.

It is also necessary to add an opacifier to the wax to prevent in-depth radiative heating and melting and enhance the wax vaporization rate.

2.) The trick is the pyrovalve. The unburnt propellant grain in the pyrovalve prevents nitrous flow until the propellant grain is ignited. Once ignited, the nitrous must pass through the hot propellant gases which causes the nitrous to decompose into hot oxygen which is above the auto-ignition temperature of the wax and therefore will react virtually instantly. The propellant is either BP or APCP which are both easy to ignite with a standard igniter.

Bob
 
DRAGON64 said:
Using Todd's hybrid design program would go along way to aid in determining this... Simulating is best.
Click to expand...

I have HDAS 1.6 but has no fuel data parameters for Paraffin. Do you have values or know where to get them?
 
jderimig said:
I have HDAS 1.6 but has no fuel data parameters for Paraffin. Do you have values or know where to get them?
Click to expand...

HDAS 1.6 is the latest I have as well, and I too have been searching for the paraffin parameters. I am hoping that some of the college documents, like those from Stanford etc. which are published online, could be sharing these numbers...
 
DRAGON64 said:
Sure wish we had a nice hybrid forum, much like this layout, that we could use to share & discuss the particulars abroad.
Click to expand...

I did setup a hybrid forum a little while back.. but as with most of the hybrid forums, it's seeing little action
And I've been a bit slack on getting the word out as well

https://hybridrocketryforum.com/
 
Last edited:
Here's a little test engine we're putting together, to test fire some various grains
HDPE, waxes, etc..

4In Hybrid Test Article a05.jpg
 
EMiR said:
I did setup a hybrid forum a little while back.. but as with most of the hybrid forums, it's seeing little action
And I've been a bit slack on getting the word out as well

https://hybridrocketryforum.com/
Click to expand...

EMiR said:
Here's a little test engine we're putting together, to test fire some various grains
HDPE, waxes, etc..
Click to expand...

Registered, and as soon as I get a chance to work in my website, I will add you to my links... I'm glad the site is still active.

Nice plumbing on your stand, looking forward to reading more on your progress, thank you for sharing.
 
Hybrid makes you HAPPY ....

P1070842.JPGP1070951.JPGP1080017.JPGP1080018.JPGP1080019.JPG

Eagle Claw 4, 3x Cluster, HYB54 Custom ...all hybrids...

Thx to Thomas Schmid, his rights & artwork
 
Last edited:
Dragon,

I would love to see a sketch of that setup with the Estes motor

Mike K
 
kramer714 said:
Dragon,

I would love to see a sketch of that setup with the Estes motor

Mike K
Click to expand...

Mike,

I have multiple images of the ignition squence that I have rendered. They are not of a final design, but more of a concept I started tinkering with, which is solely based off of a local fliers original works. Again, these works can all go back to Bill Colburns design in his hybrid manual. I can post them here if there is no objection... there is no data or formula specifics, just images with sequence labeling etc.
 
FRESH RELOADS !

Talking with Contrail it appeared that fresh reloads have been mixed, some with new flavors *lol*... I can highly recommend the new sparkies in 54 and 75mm, from J to L... I understand the new 75mm are now with new grain geometry and increased performance, I con also confirm... diamonds are also now men's best friends...(see below my A4 flight last week) Hybridz moving forward!

new 75 diamonds.jpg
 
gotta love those Contrails...

Aurora 2012 a3.jpg
 
Last edited:
However it would be great to have an opportunity of choice the legal propulsion, so you are in better position than us ;).

Damian[/QUOTE]

Believe me, brother, we have our problems, too, and I'm not just talking rockets;)

cecil
 
Pretty standard Carbon Fin Can and Carbon upper tube rocket, FG Nose cone and ali tip, Comspec tracker in the Nose
and a RattW AARD for the dual deployment from the single tube.
Had 2 Ravens on board, one in the nose for apogee deploy, and one mounted at the top of the engine, controlling the AARD
The engine was the 75mm Contrail M2281
 
Denis,

I hope you are right but I've been told new loads and certifications have been coming for a few years now.... I'm really hoping you are right! It will be awesome to burn some new loads! :) Yes I do have room for more in the reload pile. ;)

Jason

legranddudu said:
FRESH RELOADS !

Talking with Contrail it appeared that fresh reloads have been mixed, some with new flavors *lol*... I can highly recommend the new sparkies in 54 and 75mm, from J to L... I understand the new 75mm are now with new grain geometry and increased performance, I con also confirm... diamonds are also now men's best friends...(see below my A4 flight last week) Hybridz moving forward!

View attachment 183235
Click to expand...
 
Jason,

I have got myself already the all new "White Smoke" reloads in 54mm and the new designed M711 Black Smoke.
Both are EX at this point but to my experience the white smoke pushes like the Black Gold fuel and the BS with new design is similar to the old one but shows beautifull diamonds now. My subjective view...

I was told my next shippment (hoppefully soon here) shall include brand new Sparkies for the 75mm, with new grain geometry and fuel mixture, obvioiusly very similar or better as the sparky 2 in 54mm. I will report (another burning field *lol*)...

Denis
 
EMiR said:
Pretty standard Carbon Fin Can and Carbon upper tube rocket, FG Nose cone and ali tip, Comspec tracker in the Nose
and a RattW AARD for the dual deployment from the single tube.
Had 2 Ravens on board, one in the nose for apogee deploy, and one mounted at the top of the engine, controlling the AARD
The engine was the 75mm Contrail M2281
Click to expand...

Not sure I got your deployment concept clearly understood...sounds intersting. Can you just explain how it did work?
Thx
D.
 
Doing dual deployment from a single tube, is where you use a device like Ratt works AARD or tethers which can be bought around the place.
the process involves the nose cone and drogue chute coming out at apogee, whilst the main is held in the same tube until low Alt is reached, where at that point the tether or AARD releases what ever is holding the main chute in, allowing it to come out
usually under the pull of the drogue.
 

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