How Many Hybrid fliers are out there?

[dragon_rider10]

Yup. All of the NEFAR hybrid attempts yesterday were students participating in the Florida Space Grant Consortium contest.
Most of these kids had never seen a rocket, much less a hybrid motor, before this contest...

When you toss out the contest flights, NEFAR sees hybrid success on par
with commercial APCP motors.

That explains it. Thanks! Between the contest hybrids and the fouled up LPR rack, i'm thrilled we saw any flights yesterday at all. I remember that big hybrid at the March launch which was just incredible once they got it airborne. Fantastic sound to the engine. a rumbly throaty roar which sounded like something out of Star Wars episode I.

 

[Jclark]

Thanks, Bob, that was a great summary.

The one operation that is typically *not* automated and must be performed "up close and personal" is opening the main valve on the supply cylinder. The racing car people have motor drives to automatically open and close the main valve but that appears to be a convenience for them not something they do for safety's sake.

How much should we be worried about shock transients or line contamination "incidents" during the opening of the main valve? Is opening the main valve "slowly" adequate? Should we be doing any routine cleaning of fittings after our tanks have been hanging around the garage?

And, of course, one should always be cautious about a gauge rupturing at pressurization or of a line flailing about if it comes loose from a fitting.

Thanks in advance!
Best wishes,
Will

The majority of commercially manufactured Hybrids have the same built in failure modes as composite motors, snap rings will fail at a much lower pressure than the case, as will threaded closures. The 100' distance for filling is somewhat arbitrary, because if their is a failure in the tank, their is no guarantee, that you are safe at that distance. their have been instances with compressed gas cylinders where people have been injured or killed, even from 100' away.
Most of these tanks are not dot approved, and as such do not have a large safety margin; therfore, the responsibility of safe operation of the system falls on the operator, most hybrid motors should not be filled if the tank pressure is above 900 psi, as an absolute max. That being said, i have had a contrail fail from over pressurization during filling, and it was pretty uneventful, the aft snap ring failed, and everything came out of the back of the motor: nozzle, fuel grain, and injector, the rocket flew about 15' in the air, then crashed to the ground.

 

[MarkII]

This is all very informative. Thanks, everyone, for sharing your real-world experiences.

MK

 

[Kira_Majeric]

So, Jeremy is now saying that I need to learn about and eventually fly hybrids so there can be two people who fly them where ever we go. . . .

I saw that a lot of you have Sky Ripper Systems, what are your opinions on those? I am reading up on them, but I would like opinions before I spend the money. And this is one that he does not have....yet.

 

[troj]

I saw that a lot of you have Sky Ripper Systems, what are your opinions on those? I am reading up on them, but I would like opinions before I spend the money. And this is one that he does not have....yet.

Disclaimer: I used to own one of the two SRS prototype motors, and did some of the initial test flights. I no longer have the motor, because an early design proved to have some problems, and in the process damaged the case.

Now, that said, I encouraged Todd to design and get the motors into production, because I saw the amount of work he was putting into it. He's really done his homework and is actively involved in trying to deliver a quality product, and quality support.

I've had zero complaints about my SRS hybrids -- the production motors have worked very well.

-Kevin

 

[Kira_Majeric]

Disclaimer: I used to own one of the two SRS prototype motors, and did some of the initial test flights. I no longer have the motor, because an early design proved to have some problems, and in the process damaged the case.

Now, that said, I encouraged Todd to design and get the motors into production, because I saw the amount of work he was putting into it. He's really done his homework and is actively involved in trying to deliver a quality product, and quality support.

I've had zero complaints about my SRS hybrids -- the production motors have worked very well.

-Kevin

This is good to know. Thank you.

 

[brianc]

I saw that a lot of you have Sky Ripper Systems, what are your opinions on those? I am reading up on them, but I would like opinions before I spend the money.

I have a full set of both the 38mm and 54mm motors (plus a 29/125 that
needs to be found or replaced soon).

I love 'em!

 

[Kira_Majeric]

I have a full set of both the 38mm and 54mm motors (plus a 29/125 that
needs to be found or replaced soon).

I love 'em!

thank you. What happened? It looked like you were venting out the bottom as well as the side.

 

[brianc]

thank you. What happened? It looked like you were venting out the bottom as well as the side.

The venting at the fill tube was a leak, unrelated to the loss of the rocket.

If you notice near the apogee (where the video zooms in) there's a puff
of an ejection charge. My suspicion is the nose cone popped off instead of the rocket separating in the center.

Unfortunately, the unpainted BT-60 looks exactly like the corn
stalks where I estimate the splash zone is...

 

[Kira_Majeric]

The venting at the fill tube was a leak, unrelated to the loss of the rocket.

If you notice near the apogee (where the video zooms in) there's a puff
of an ejection charge. My suspicion is the nose cone popped off instead of the rocket separating in the center.

Unfortunately, the unpainted BT-60 looks exactly like the corn
stalks where I estimate the splash zone is...

I`m sorry to hear that. Hopefully someone will find it.

 

[billspad]

I'll add my praise to SRS. I can't say that I've had no problems but the time I did Todd stood behind his product even thought it wasn't clear that it wasn't my fault.

 

[ttabbal]

I really like my SRS motors. I have the 38mm set and the long 54mm motor. Most of my failures have been igniter related as well, the pre-heater didn't ignite. And if that little AP slice didn't go, a full motor probably won't either. I really need to find a nice hot, slow igniter for these things.

I did have a fill stem fail to release on a 54mm K flight. That was... interesting. It took my GSE with it, breaking the fill manifold before the BFV, so I lost a LOT of nitrous before we could get to the tank. I think I messed up building it though, it was only my 2nd 54mm flight. The rocket was shredded and the electronics for the GSE destroyed. I still need to repair them. That'll learn me not to secure my fill line to the ground and/or pad.

I wish SRS would release the 98mm version. I'd love an L/M hybrid with reasonable cost reloads. Most of the existing Hybrid loads at that level cost almost as much as a solid. I may as well just buy the AP instead. Todd has talked about <$100 M reloads, THAT I would buy.

I'd probably by an Alpha if they had bigger motors available. A K would be nice. I have enough I class stuff I can fly, so the hardware cost just isn't justifiable in my own mind. Perhaps if I get a windfall. I wonder if Ed would be interested in selling them for research flights? I have TRA L2 and the local club does research launches a few times a year. If I could get hardware and loads to do an L and M flight, I'd be interested, even non-certified.

 

[AlphaHybrids]

I have a 83mm K motor, 2000 Ns. It took a 5# 4" rocket to 8k feet at 2004 Springfest in Vegas. If people want more motors developed then support of the current product is needed. You can't expect any manufacturer to run in the red.

Edward

 

[brianc]

I really like my SRS motors. I have the 38mm set and the long 54mm motor. Most of my failures have been igniter related as well, the pre-heater didn't ignite. And if that little AP slice didn't go, a full motor probably won't either. I really need to find a nice hot, slow igniter for these things.

I've had 100% success with the RocketFlight Magnelite kit-
https://www.rocketflite.com/products_ml.htm

 

[AlphaHybrids]

I use 2 1/16" holes drilled opposite each other. I then put two bare wire wrapped nichrome igniters in each hole. Never had an ignition problem, even when they have been loaded for 6+ months.

Edward

 

[Kira_Majeric]

I've had 100% success with the RocketFlight Magnelite kit-
https://www.rocketflite.com/products_ml.htm

Jeremy has their ematches, they work great on everything except his arts altimeter. Luckily the back up altimeter fired.

 

[WillMarchant]

...except his arts altimeter. Luckily the back up altimeter fired.

<cough>ground test</cough> :gavel:

 

[troj]

Jeremy has their ematches, they work great on everything except his arts altimeter. Luckily the back up altimeter fired.

Is he using two batteries with the ARTS? If not, that may well be his problem.

Also, every altimeter on the market is different, in terms of its firing circuitry, and the current delivered. That's why it's always best to ground-test them, first.

The "dip your own" matches aren't the same as DaveFire matches, and testing is important with them.

-Kevin

 

[Kira_Majeric]

Is he using two batteries with the ARTS? If not, that may well be his problem.

Also, every altimeter on the market is different, in terms of its firing circuitry, and the current delivered. That's why it's always best to ground-test them, first.

The "dip your own" matches aren't the same as DaveFire matches, and testing is important with them.

-Kevin

We are going to do some ground tests with his dipped matches this year. He said that he has the old version....1.5? He is looking..... He is going to look into installing another battery for it.

 

[troj]

We are going to do some ground tests with his dipped matches this year. He said that he has the old version....1.5? He is looking..... He is going to look into installing another battery for it.

My understanding, from folks who fly them, is that you never want to use an ARTS for deployment without two batteries.

If he has questions, have him contact Darren Wright -- Darren will either know the answer, or will know who does.

-Kevin

 

[Kira_Majeric]

My understanding, from folks who fly them, is that you never want to use an ARTS for deployment without two batteries.

If he has questions, have him contact Darren Wright -- Darren will either know the answer, or will know who does.

-Kevin

I am passing that along, thank you. He is also updating the firmware, so that might help as well.

 

[ttabbal]

I use 2 1/16" holes drilled opposite each other. I then put two bare wire wrapped nichrome igniters in each hole. Never had an ignition problem, even when they have been loaded for 6+ months.

Edward

So you end up with 4 ignitors in each motor? Interesting. I might have to try that trick. I'd been considering stuffing a pyrodex pellet into the hole like the CTI motors.

I might try the Magnalite as well, looks like good stuff. Paint the pyrogen on the pre-heater?

It's just really irritating to have to dump. That's one of the reasons I'd be interested in some larger pre-filled motors.. hint.. hint..

I want some Alpha style L/M hardware and reloads. Even non-cert..

 

[AlphaHybrids]

Sorry, I use 1 bare nichrome wire igniter per hole. I wouldn't use a pyrodex pellet. I've seen bad things happen when those melt the fill hose just enough to soften it. Then it goes out and you dump all the nitrous w/o igniting the motor. Also, there isn't a good way to retain the pellet at the top of the motor to keep it from traveling.

Alpha Hybrids will not sell non-certified hardware. But supporting current hardware choices makes it much easier on us to justify developing larger hardware. You can't expect manufacturers to build bigger things when no one is even supporting the current lineup.

Edward