# Need source material on hybrid propulsion

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#### Funkworks

##### Well-Known Member
I was going to prepare for Level 1 certification, but apparently, there are plenty of questions on hybrid propulsion on the written exam. I really don't care for hybrids yet, but I need a book or something to prepare for the written exam. What do you recommend reading?

#### Steve Shannon

##### Well-Known Member
TRF Supporter
Unless you’re a member of CAR, there is no written exam for Level 1.

#### Funkworks

##### Well-Known Member
Yes it's the CAR.

#### G_T

##### Well-Known Member
If you ignore the youtube videos and sites just interested in capturing your clicks, there is a great deal of info online. I've done design work on hybrids, but have no idea what CAR requires for knowledge. So I don't know how to answer your question.

Gerald

#### Funkworks

##### Well-Known Member
It's a good bet the CAR level 1 written exam is similar to the NAR level 2 written exam. Any material at all on hybrid rockets would be useful. I'm at my 4th book on rocketry (model and real) and still have nothing useful text on hybrids. All I found online was hyperTEKhybrids and that's not enough either.

#### grouch

##### Well-Known Member
Concept or details? Concept is simple. You have a material that burns slowly that acts like a glow plug. Then you have a gas that is ignited by the burning material. When the gas is gone, so is the thrust.

Look into the diagrams on Rattworks site. There is some source material there to help.

#### Tim51

##### Well-Known Member
Aspire Space based in Scotland are the go to experts on hybrid motors on this side of the pond. They have a very informative website with well written downloadable technical papers etc: www.aspirespace.org.uk

#### Zeus-cat

##### Well-Known Member
Contact CAR and ask what do you need to know. Tests should not be designed so that people fail. Tests should be used to verify that people know and understand what they are being tested on. So putting questions on a test that people can't answer is utterly pointless. CAR should point you towards the things you need to know.

#### G_T

##### Well-Known Member
My guesstimation is you need to know:

Safe tank temperature range for filling/flying.
Something about safety procedures for fill/fly/dump.
Safe standoff distances.
How using a hybrid alters the stability computations.

In other words, how to safely be around them and use them. But if I were you I'd contact CAR and ask what they expect.

If you were actually working with hybrids, I'd also expect you to know:

Safe handling of nitrous (and/or your oxidizer of choice. Each has different issues).
Hybrid failure modes.
Types of hybrid ignition.
Rules/laws regarding transportation and storage of nitrous (depends on where you are as different locations have different rules).

And of course I'm not CAR! But I do work with EX hybrids.

Gerald

#### CoyoteNumber2

##### Original San Diego High Power Rocketry
Does the Tripoli Level 2 test still have hybrid questions? I would think CAR's questions would be similar. Does CAR not publish a study guide?

#### crossfire

Does the Tripoli Level 2 test still have hybrid questions? I would think CAR's questions would be similar. Does CAR not publish a study guide?
Yes TRA still has hybrid questions.

TRF Supporter

#### G_T

##### Well-Known Member
I'm not sure they should. Hybrids can still show up and are legit to launch. That means people who may be at the away cells need to know something about safety around them.

Gerald

#### dhbarr

##### Amateur Professional
If anybody gets a new hybrid load certed it makes sense to keep the coverage, otherwise I suppose they'll naturally age out.

#### Steve Shannon

##### Well-Known Member
TRF Supporter
I'm not sure they should. Hybrids can still show up and are legit to launch. That means people who may be at the away cells need to know something about safety around them.

Gerald
If anybody gets a new hybrid load certed it makes sense to keep the coverage, otherwise I suppose they'll naturally age out.
We’re trying to overhaul the questions and make them more relevant to current practices and correct deficiencies with the current study guide. The number of hybrid questions seems to exceed the number of hybrid motors launched nowadays. [emoji851]

Gerald’s point is well made; we need to make sure not to fail our range volunteers.

#### Ez2cDave

##### Well-Known Member
They might go away.
Just like hybrid motors have been doing, ever since we won the BATFE lawsuit . . .

#### mwtoelle

##### Flying since 1977
I can probably count on one hand the number hybrid motors that I have seen launched since 2010. In 2005, probably about 40%+ of the HPR flights that I have seen were hybrids. I think that the complexity of the hybrid GSE and extra requirements (electronic ejection) to fly hybrids have seen their usage decrease since 2008.

#### kramer714

Still some of us launching hybrids. $95 for a M hybrid.... one reason I launch them. If anyone is interested, I will be launching hybrds at NSL at Lucerne Dry Lakebed. Mike #### Ez2cDave ##### Well-Known Member Still some of us launching hybrids.$95 for a M hybrid.... one reason I launch them. If anyone is interested, I will be launching hybrds at NSL at Lucerne Dry Lakebed.

Mike
Mike,

Which "Brands" of hybrids are you flying ?

The pic below is of my HYPERTEK hybrids, shortly before I sold everything, after we won the BATFE lawsuit. Some of those were original prototypes and early models that used the "Hammerhead" tanks ( commercial Oxygen cylinders ) . . . The large one is the "Armageddon M" and the next one down is the "Earthquake L". Those tanks were 4.5" in diameter.

Dave F.

#### ericm541

##### Well-Known Member
Hypertek still in operation?

#### Ez2cDave

##### Well-Known Member
There are a few places that still may have a few pieces laying around . . .

It looks, to me, as though Hybrids are dead, ever since we won the APCP lawsuit against the BATFE.

#### G_T

##### Well-Known Member
Most rocket folks purchase a commercial motor to launch. A small percentage make their own motors - APCP, Sugar, etc. The etc category is smallest, and includes Hybrids. Most folk just want to launch. For that majority, simpler is better. Solids are very simple when you aren't making the propellant.

Hybrids are intrinsically more complex to deal with than solids at launches. Solids are actually more complex to deal with for EX, if one ignores the hardware required for the Hybrid!

Commercial hybrids for the most part have hardware that is heavy for the total impulse, and have rather inconsistent performance being rather temperature sensitive. The first can be solved by using larger hybrids where the hardware mass fraction is lower. The second can be solved by various means, such as chilled nitrous as in my EX hybrid experiment (I'm not the first to do it).

Hybrids also tend to be long and thin (too much so really) and tend to need special purpose rockets. That's a big strike right there. Most kits are designed for motors no longer than the readily available commercial cases.

Most clubs, if they have launch equipment for hybrids, don't bring it out to launches. Many who have hybrids don't have their own GSE. That about ends it right there. Advertise some months in advance that you will have hybrid GSE set up at a launch, and see if people show up to launch hybrids. Not setting up for hybrids and then finding they don't show up? That's sort of obvious. But it is not necessarily an accurate gauge of interest!

Gerald

#### timbucktoo

##### Well-Known Member
Staff member
Global Mod
We’ve got 2 flyers at my club who are really into hybrid motors. We fly NAR rules so they can only use commercial motors & as far as I know Contrail is the only source out there today. We even had Brad from Wilson F/X make us a beauty of a wireless hybrid launch controller. Definitely not dead!

#### ericm541

##### Well-Known Member
I'm just getting into hybirds, I have full 38MM Contrail set,looking forward to flying at URRF this year.

#### G_T

##### Well-Known Member
I was hoping to also with my EX M. Have GSE now but not tank or nitrous. Perhaps this fall sometime.

Gerald

#### Ez2cDave

##### Well-Known Member
So, who is currently manufacturing hybrid motors ?

Staff member
Global Mod
Last edited:

#### Banzai88

##### Lvl 1,Wallet....Destroyed
So, who is currently manufacturing hybrid motors ?
As stated in post 23 & 24, Contrail.
https://contrailrockets.com/
A valid question, since their web page hasn't been updated since 2010, with most of the pages remaining untouched since 2008. At least the information is still up and accessible.

The instruction sheet on assembling the motors is nicely documented with simple instructions and good pictures.

#### timbucktoo

##### Well-Known Member
Staff member
Global Mod
They are active on Facebook & like I said, 2 flyers at my club are currently buying motors from them.

#### Ez2cDave

##### Well-Known Member
The "Book of the Dead" . . . Skyripper, West Coast Hybrids, Hypertek, Aerotech, Rattworks . . .etc, etc, etc.

I repeat my question . . . Who is currently manufacturing hybrid rocket motors ? (except, "possibly" Contrail )

Dave F.

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