Hybrids For 2016

AlphaHybrids said:

UhClem - you will be waiting a long, long time

Johhnie - have you flow the 54mm system of mine yet?

Edward

Click to expand...

This season I will be flying system, the SkyRipper system and my new Contrail... short answer... no not yet.

AlphaHybrids said:

Attached is an image of the fill stem/system that I use. It attaches to the side of the rail and keeps the hose from flopping around. You just attached a fitting to the fill hose and then that uses flare fittings to connect to the tank.

The nice thing is that with the elbows and bends it puts the connecting right in the middle of the 1010 rail. Then you just use the 1/8" pipe and slide it to the correct diameter of motor. A 6" nipple will handle rockets up to 7.5" diameter with ease.

View attachment 281257

Edward

Click to expand...

How much to make me one?

I don't know what it would cost to make one. That is my original and I've upgraded the pipe going through to 1/4 NPT stainless steel schedule 80. I bent the 1/8 brass ones too often. Odd that there is enough force down to bend them. I've also had it unscrew fittings before. Just the nipple is a $15 component, plus all the brass fittings. I also added a triangle gusset underneath so that everything rests on a shelf to keep the forces from bending anything. No fun to launch once and it bend and not be able to launch again.

Just a quick tally and there is at least $40 in parts in the current setup I have. I'd rather do a drawing and give people a parts list for them.

Edward

Those of you who own the Contrail 3200cc system; have you found a more elegant way to reliably light the motor? The combustion chamber is so full of tubing, it is a wonder that the motors do not blow the nozzle from plugging. Right now, the level of complexity and reliability are becoming a concern to me... I would hate to hold up a launch due to a "hybrid issue" like we have all experienced in the past... no one likes a hybrid related delay at a launch.

From my simulation of similar motors, the nozzle throat area to injector area ratio is low. I wouldn't be concerned about the tubes.

Gerald

G_T said:

From my simulation of similar motors, the nozzle throat area to injector area ratio is low. I wouldn't be concerned about the tubes.

Gerald

Click to expand...

I was watching the video of "legraddudu" putting a Contrail motor together (3-part series), and I was in shock at all of the start up tubing he managed to stuff down the throat of the motor.

Having launched most of the hybrids out there, the Contrail has the best 'button to launch' ratio. My flight engineer (aka the boy) tells me that when I give him the signal to launch he pushes the button and the rocket lights instantly. He has pushed the button on most of the hybrids out there and the contrail is best 'lights like a solid' according to him. I have never had a misfire or premature spit out tube after 5-6 flights with the 75mm M. It takes me 10 minutes or less to clean old reload and put in a new one.

Couple of tricks (don't all of the hybrids have them?)
1)make sure that the pyrodex pellets are taped close to the bulkhead, don't go nuts with the amount of tape.
2) get a good socket set for screwing in the injectors
3) I don't use Tom's igniters, I use Quickburst ones.
4) make sure that the vent hose is secure, I have lost 2 of the vent 'plugs' already.

The tube 'mess' does spit out clean at launch.


Mike K

Mike - thanks for the input, that is definitely good to know for the big Contrails. Here was what I was imagining happening...

[video=youtube;_Vyw3BjgDVQ]https://www.youtube.com/watch?v=_Vyw3BjgDVQ[/video]

DRAGON64 said:

Those of you who own the Contrail 3200cc system; have you found a more elegant way to reliably light the motor? The combustion chamber is so full of tubing, it is a wonder that the motors do not blow the nozzle from plugging. Right now, the level of complexity and reliability are becoming a concern to me... I would hate to hold up a launch due to a "hybrid issue" like we have all experienced in the past... no one likes a hybrid related delay at a launch.

Click to expand...

Hey Johnny,

You won't find a simpler or more reliable method to light one of these up! I'll have to look at Dudu's video and see if he did it per instructions, but doing it per instructions and as Mike said below in his tips don't get crazy with the tape on the pellets and run a layer down the whole set of tubes to keep things "tight" and there will be zero tube/nozzle issues. I also don't use the supplied lighters. Just use whatever is reliable and handy. About the only down side to this system is that it is fairly heavy. Sure wish we could get the "new style" 75mm system certified. Don't think we will ever see it due to lack of sales...

Jason

jason-and-his-toys said:

Hey Johnny,

You won't find a simpler or more reliable method to light one of these up! I'll have to look at Dudu's video and see if he did it per instructions, but doing it per instructions and as Mike said below in his tips don't get crazy with the tape on the pellets and run a layer down the whole set of tubes to keep things "tight" and there will be zero tube/nozzle issues. I also don't use the supplied lighters. Just use whatever is reliable and handy. About the only down side to this system is that it is fairly heavy. Sure wish we could get the "new style" 75mm system certified. Don't think we will ever see it due to lack of sales...

Jason

Click to expand...

There is that word again..."heavy" I was hopoing that the down side to a stationary injector set-up like Contrail employs, would not mean that the system would have excessive weight. From the few videos I have seen of the 3200cc system in action, the motor combos seem to have enough initial thrust to get the various airframes off the pad. I would build custom anyway, as these motors were not made to loft conventional rockets, but instead they require long slender airframes. Thanks for the feedback Jason!

]

DRAGON64 said:

There is that word again..."heavy" I was hopoing that the down side to a stationary injector set-up like Contrail employs, would not mean that the system would have excessive weight. From the few videos I have seen of the 3200cc system in action, the motor combos seem to have enough initial thrust to get the various airframes off the pad. I would build custom anyway, as these motors were not made to loft conventional rockets, but instead they require long slender airframes. Thanks for the feedback Jason!

Click to expand...

Plenty of thrust just a 'different vibe' with the hybrids. The 75mm Contrails, and 75/100 mm Hyperteks will certainly lift a good size rocket but this is big rocket slowly lifting off the pad and accelerating for a long time kind of stuff. The 'pizza spool' rocket was on a hybrid too btw.

Mike K


View attachment AUT_1646.JPG

What is the OD/ID of the Contrail 75mm motors? Is it standard 2.75 ID tubing?

Edward

IIRC, the tank is thicker wall than average, and the CC is a bit thinner. I'm in the process of machining something similar but a bit longer and more complex, where I'm taking some effort to minimize excess mass. It will come out a couple pounds lighter, roughly, if I get the time to finish it!

I no longer have Contrail's motors so I cannot check dimensions or weight directly.

Gerald

AlphaHybrids said:

What is the OD/ID of the Contrail 75mm motors? Is it standard 2.75 ID tubing?

Edward

Click to expand...

Yes, Contrail uses 2.75 inch ID tubing. OD is 75mm. Custom tubes are fairly easy to make because Contrail uses bulkhead bolts instead of grooves on their 75mm system so you don't need a lathe.

DRAGON64 said:

Those of you who own the Contrail 3200cc system; have you found a more elegant way to reliably light the motor? The combustion chamber is so full of tubing, it is a wonder that the motors do not blow the nozzle from plugging. Right now, the level of complexity and reliability are becoming a concern to me... I would hate to hold up a launch due to a "hybrid issue" like we have all experienced in the past... no one likes a hybrid related delay at a launch.

Click to expand...

I have never had a problem lighting a Contrail 75. I used to be concerned that if I kink the tube the ties two of the injector's together that it would burst. It has never been a problem. I have flown the slow nozzle which has the smallest throat and it spit out the fill tubes, no problem. If I was to buy one motor it would be the 75mm/3200cc with the medium nozzle.

karlbaum said:

I have never had a problem lighting a Contrail 75. I used to be concerned that if I kink the tube the ties two of the injector's together that it would burst. It has never been a problem. I have flown the slow nozzle which has the smallest throat and it spit out the fill tubes, no problem. If I was to buy one motor it would be the 75mm/3200cc with the medium nozzle.

Click to expand...

I was looking at getting the med nozzle 3200cc system Doug Pratt, and the 5" Terminator airframe from Rocketry Warehouse... of course the airframe would need to be stretched a bit to accomadate the longer 53" motor.

Attached is a PDF of a thrust curve of a motor that I recently fired. Performed very nice.

Edward

View attachment Hybrid Test.pdf

kramer714 said:

Figured out the LDRS hybrid project,

Double Ratt, rocket launching on 2 Ratt 65mm K motors. Should be ear splitting loud.

-details to follow-

Mike K

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The K240 sounds like you are throwing a bag of cats into a chainsaw. I can't imagine two of them.

Edward

AlphaHybrids said:

The K240 sounds like you are throwing a bag of cats into a chainsaw. I can't imagine two of them.

Edward

Click to expand...

yup, it is the loudest rocket I have ever launched, two should be fun!!!

Come out to LDRS Edward?

Mike K

AlphaHybrids said:

Attached is a PDF of a thrust curve of a motor that I recently fired. Performed very nice.

Edward

View attachment 282814

Click to expand...

I'm a little surprised that the nitrous pressure was that low, must have been cold....

Mike K

It was tested in February in Colorado...

It was a bit over 60 degrees out and the tanks was filled and then everything was sitting in the sun for just over an hour. The previous tests had 750 PSI and 800 PSI as the starting pressure.

Edward

Just did four more tests over the weekend. Tested my 3" N motor. Came out a just over 15,000 Ns with an average thrust of ~335 pounds. The rocket weighs just a hair over 25 pounds, so it should make for a great ride. Chopped the rocket down by 6" more so now the total length is 108". Now, just need to get a launch with an extended waiver to fly it. First opportunity is June, then July, then October. Waiver is for 35k, should be able to tickle that easily.

Have been working on my mini-throttle motor some more. Just got everything fabricated and am going to test that next. The electronics are done and once the tank is equalized all you have to do is tell the controller to go and it fires the igniter, verifies that the preheater is lit and then opens the control valves to start the motor. It also shuts off the supply tank when pressure drops to 100 PSI.

The one bummer is that I have to fill, let the tank equalize, fire, then repeat. The equalizing part can a bit between firings so two a day is about the maximum. I do have a warm tank (75F) of water that after filling I let it equalize in.

Edward

I am back and I want fun ))))))
Here my ideas: finish my 5.5 Phoenix and fly with some K, fly my 3x hybrid cluster again on a 3x J this time... and work this 2 stage hybrid project to an end
Should be enough for 2016 *lol*

DRAGON64 said:

Mike - thanks for the input, that is definitely good to know for the big Contrails. Here was what I was imagining happening...

[video=youtube;_Vyw3BjgDVQ]https://www.youtube.com/watch?v=_Vyw3BjgDVQ[/video]

Click to expand...

Guess what it is not a real CATO (hot explosion) but a cold burst due to a huge gaz expansion in the upper part of the booster. You see the booster nearly intact at the end. I had this once on the 54mm contrail. The monotube close at the top with a bulkhead, maintained by a kind of clip (lost the right name in english sorry). If this is not in place properly it just opens at a certain pressure and all the gaz expands in a fraction of a second in the rocket... 52 bars cold booster *lol*... The big contrail do not have this risk by definition. The top bulkhead is screwed from the side.

Installing snap rings with the flat side and making sure they snap into place is on my checklist. I've seen this happen in solids and it definitely is a bit more violent as the motor expels sometimes flaming grains into the rocket.

I've been doing *lots* of testing this year. Every time I get done developing a motor and am at the point I could fly it, I just decide to upscale it to the next logical size. So, I have a nice 3" N motor, but now I've decided that I just need to have a 6" heavy lifting motor for a BDR. The next motor will be 6" diameter x 84" long.

Edward

legranddudu said:

I am back and I want fun ))))))
Here my ideas: finish my 5.5 Phoenix and fly with some K, fly my 3x hybrid cluster again on a 3x J this time... and work this 2 stage hybrid project to an end
Should be enough for 2016 *lol*

Click to expand...

Long time no see... looking forward to more of your hybrid experiences. That Phoenix sounds pretty sweet, do you have a thread or another forum where you are building this rocket?

AlphaHybrids said:

The next motor will be 6" diameter x 84" long.

Click to expand...

OMG! Specs?

kramer714 said:

Figured out the LDRS hybrid project,

Double Ratt, rocket launching on 2 Ratt 65mm K motors. Should be ear splitting loud.

Click to expand...

What day of LDRS do you plan to launch this?

kramer714 said:

Having launched most of the hybrids out there, the Contrail has the best 'button to launch' ratio. My flight engineer (aka the boy) tells me that when I give him the signal to launch he pushes the button and the rocket lights instantly. He has pushed the button on most of the hybrids out there and the contrail is best 'lights like a solid' according to him. I have never had a misfire or premature spit out tube after 5-6 flights with the 75mm M. It takes me 10 minutes or less to clean old reload and put in a new one.

Couple of tricks (don't all of the hybrids have them?)
1)make sure that the pyrodex pellets are taped close to the bulkhead, don't go nuts with the amount of tape.
2) get a good socket set for screwing in the injectors
3) I don't use Tom's igniters, I use Quickburst ones.
4) make sure that the vent hose is secure, I have lost 2 of the vent 'plugs' already.

The tube 'mess' does spit out clean at launch.


Mike K

Click to expand...

Same with my Contrail M motors, x2 on your notes. We use a walkie talkie to stay in touch with the LCO when we start the fill. He usually stays at his post even when the racks are reloading. (We are at the away cell anyway observing the fill) Just when the fill is complete, we give him a call , he cuts in with a 5 sec countdown and off it goes screaming like a banshee. No more delay than any other rocket at the away cell.
IMHO, the large contrails are the most simplistic and sensibly designed motors, uses standard push-tube type connectors as the oxidizer jets, brilliant.

Not bad price, $100 and some NO2 for a screaming M that wows everybody in attendance.

LDRS Plan,

First of all I will be heading out to LDRS for Hybrids, plan to launch at least once a day Friday, Saturday and Sunday. My biggest problem is the day job, I'm way behind on building. John will be bring out his tank I think, plus I will have GSE and tanks,

Anyone planning on coming out? with Hybrids?

Mike k

Just to add on the "sound" topic...

To me after many launches it appears that the 54mm contrails sound much more agressive/diabolic than the big brothers in 75mm which are deeper sound.
Saying differently: the 54mm sound military and the 75mm more civilian...if you would close your eyes...

This has of course by no mean a scientific explanation, just feeling and reflecting what the crowd said to me many times.
Sooo... if you want to dry your underpants & socks and freeze your blood at the launch... just cluster the 54mm contrails...