Hybrids?

[Max Thrust]

I'm a very recent BAR who is utterly disgusted with this crap that BATFE is pulling on the high powered rocketry community. As a privacy nut, there is no way I want a BATFE agent coming around my place or even knowing I exist, yet, I want to end up certified to level 3. Given that, it would seem that the only choice for me is to go with Hybrid motors.

Can I get some feedback on the different motors? RATT? Hypertech? etc.? I like the idea of cheap reloads and no LEUP required. Anyone?

Warren

 

[Papa Elf]

To get started, the RATT system is the best deal... cheap, easy to use, less ground support. However, the loads are limited, and low thrust...

Hypertek offers a variety of loads with thier system, but it is expensive and complex. With hypertek, if you want to buy the GSE with everything you need to fly on your own... expect to lay down almost a grand (tanks and gas included in that price)

OBTW, Welcome to the rocketry forum! You will find this a great source of information about rocketry. And this place is a lot more friendlier than other sources like RMR.

 

[Max Thrust]

I noticed that. RMR seems to be largely one guy and his minions arguing with everyone else and dissing Tripoli, BATFE and everyone else in the bargain.

Another thing, I still don't seem to have a fully clear view on what the status is of reloadable engines and grains vis a vis BATFE. What is sounds like is if it has Ammonium Perchlorate in it, they (BATFE) want you to have a LEUP. While there is theoretically an exemption for loads below 62.5 grams, I've also seen statements that they intend to regulate those as well and require a LEUP. Is there a definitive statement anywhere on this?

Max Thrust

 

[Ryan S.]

I have heard great things about skyrippper. I would go with floating injector hybrids they are simpler and more reliable as well as cheaper. RATT would probably be a good start as doug said. Hypertek has big motors though (i think Ratt may but they just came out) so you might need to get those for L3

By the way, you may find a club that has GSE for hybrids so the cost will be less

 

[Max Thrust]

Yeah... I'm thinking of joining the Tripoli prefecture in Northern Colorado to get certified and for their GSE. I like the Hypertech because it's an elegant (from an engineering standpoint) product, BUT, it's so **** expensive. I'd rather something like the RATT or similar floating injector except I'd like a little more flex in the size of the oxidizer tankage. The Aerotech looks nice but I don't like the idea of paper or cellulose as the fuel. I'd rather use Polyethylene since it burns to produce CO2 and water.

Max Thrust (Warren)

 

[Ray Dunakin]

Originally posted by Max Thrust
Another thing, I still don't seem to have a fully clear view on what the status is of reloadable engines and grains vis a vis BATFE. What is sounds like is if it has Ammonium Perchlorate in it, they (BATFE) want you to have a LEUP. While there is theoretically an exemption for loads below 62.5 grams, I've also seen statements that they intend to regulate those as well and require a LEUP. Is there a definitive statement anywhere on this?

Max Thrust

There is no "definitive statement" on it. However, there's lots of opinions and hysteria surrounding this issue. What's known is this: For now, you can still purchase "easy access" motors without a LEUP, although some of the online vendors are requiring a LEUP for all purchases just to cover their butts. Also, at most launches with an on-site vendor, you can buy and fly any motors on-site without a LEUP, you just have to do it under the "supervision" of the vendor or another LEUP holder.

So there's no reason to avoid high power composite motors at this time. The only situations where it might be a real problem is for those who do not have a local motor vendor, or if the local vendor has been spooked into requiring LEUPs for everything.

 

[Rocketmaniac]

Originally posted by n3tjm
Hypertek offers a variety of loads with thier system, but it is expensive and complex. With hypertek, if you want to buy the GSE with everything you need to fly on your own... expect to lay down almost a grand (tanks and gas included in that price)

OBTW, Welcome to the rocketry forum!

One idea might be to find a local club and see if someone there already has the GSE........ I am going to fly my first hybrid motor next month....... I am using someone else's GSE and tank...... I will buy my own fuel grain and then just pay him for the gas I use...... I know it's going to be $28 for a "J" motor plus the gas!!!!

In time, I will buy my own tank but will always use his GSE.......

 

[Max Thrust]

One of the questions I have is construction related. What do I have to do different in designing and building rockets to be flown on a hybrid engine?

Warren

 

[Rocketmaniac]

Originally posted by Max Thrust
One of the questions I have is construction related. What do I have to do different in designing and building rockets to be flown on a hybrid engine?

Well, I am no Hybrid expert....... but the following was the thread I started to build my LOC Expeditor

https://www.rocketryforum.com/showthread.php?s=&threadid=4441

 

[Rocketmaniac]

Originally posted by Max Thrust
One of the questions I have is construction related. What do I have to do different in designing and building rockets to be flown on a hybrid engine?

The only thing different I had to do was put in a longer motor tube so the tank and fuel grain was supported better...... The guys at my club told me to use a 24" motor tube....... And because of the type of tank I was going to use, I had to build it with a 54mm motor mount...........

Oh yea, there has to be a "vent" hole 11" up from the back end of the rocket (or at least for the tank I am going to be using)............

 

[Max Thrust]

How does this vent hole affect pressurization of the airframe when the ejection charge goes off?

Warren

 

[Rocketmaniac]

Originally posted by Max Thrust
How does this vent hole affect pressurization of the airframe when the ejection charge goes off?

Warren

Well.... first off....... you have to use electronics and dual deployment with hybrids as there is no ejection charge........ Second, I don't think the vent hole affects anything on the rocket......

 

[Max Thrust]

Well, I'm assuming in that case that the vent hole is blocked off from the recovery system compartment or else the ejection charge (regardless of how fired; blackpowder via flashbulb, em, or even a CO2 system) would vent rather than blow the nose off and deploy the recovery system.

Warren

 

[MarkABrown]

Warren,
You are correct. The vent hole needs to be below the uppermost bulkhead/centering ring separating it from the payload bay. The payload bay needs to be sealed or the ejection charge will vent rather than pressurize the bay.

 

[Elbmod]

I have no experience myself, but these pges came up when I was doing some research into the topic myself.

https://www.flyhybrids.org/
https://www.nowhybrids.com/

HTH

 

[daveyfire]

If you're venting a Hypertek, the vent comes out the side of the motor and is blocked off by the tank from the recovery compartment. If you're venting a RATT Works, the vent comes out the top of the motor and can be blocked off by some creative routing of the vent. In my experience, however, it doesn't really matter, because the vent is small enough that ejection gas usually doesn't have time to escape out of it before it blows off the nose cone. It's just like another pressure vent hole you put in your rockets to keep em from popping apart under boost.

Hope that helps!

P.S. Wayne's "Now Hybrids" site is great... he's our local dealer and knows A LOT about hybrids!