70 Motor 2 Stage Project > "HellBoy 70"

[troj]

If it was going to fail I was hoping it would do it earlier so I could feel like a real RSO and terminate the flight.

I can envision you holding the remote with that evil smirk on your face.... Muah Ha Hah! The Power is MINE!

Yep, that's so you.

We'll know better when Boris gets the data out of the Raven but I think it did what was best. From my point of view it looked like the rocket was horizontal or close to it at first stage burnout. That would have resulted in a power prang or a swamp landing or both.

I'm confident he'll get a good flight. Wind makes it darned tough.

-Kevin

[ClusterNut]

Here's the video I took yesterday.

http://youtu.be/1bD4Be3m_DE

[rstaff3]

I just love the close-up where you can see the individual flames! It would have been cooler if both stages had fired, of course, but it was nifty that the electronics saved it from an unsafe (or unrecoverable) flight path. Good show!

[billspad]

View from the grass.

[delta22]

This is the video from my pad and spectator cameras:



Thanks for the other videos gentlemen.

[iter]

Boris, your flights are inspiring. When I look at them, I want to add a ring of 24mm BPs around the central 38mm AP in the 4 incher I'm building.

I wonder if you can share more about your flash pan setup. In particular, I wonder about lighting the AP from an electric igniter and the BPs (or their flash pan) from the main motor's flame. This way if the main fails to start, I can avoid BPs ignition.

Ari.

[Orion14ed]

Even though the 2nd stage did not fire... What a great flight! I mean, its awesome seeing that many motors fly! I really do like the fact that the raven did not let the 2nd stage fire because of the conditions. Really shows how well it works... (It did not fire because of that... right?)

[delta22]

When you look at the sim data can you tell which conditions were not met for the second stage ignition, and what the values were?

If it was going to fail I was hoping it would do it earlier so I could feel like a real RSO and terminate the flight.

We'll know better when Boris gets the data out of the Raven but I think it did what was best. From my point of view it looked like the rocket was horizontal or close to it at first stage burnout. That would have resulted in a power prang or a swamp landing or both.

Even though the 2nd stage did not fire... What a great flight! I mean, its awesome seeing that many motors fly! I really do like the fact that the raven did not let the 2nd stage fire because of the conditions. Really shows how well it works... (It did not fire because of that... right?)

Spent some time going over the data from the Raven.

Attached are screenshots of the data that I believe is most relevant. All three images show the same graph lines, but each has the mouse pointer (and data detail box ) at different key points:
> max acceleration > 8.84 Gs > less that I expected, resulting in lower
> max velocity > 143 ft/sec
> max altitude (barometric) > 406 ft

The four lines at the very top are the true/false firing criteria used for the second stage.

The only one that never went to true was velocity, the firing criteria was 144 ft/sec and the flight maxed out at 143 ft/sec!

Bill, you almost got to be an RC LCO and fire the safety charge.

The Raven has some very slick capabilities, but this flight weathercocking too much was not the reason it did not fire the second stage. The second stage did not fire because is was accelerating about 30% more slowly than both my sims and direct rough calculations had expected, resulting in 30% lower max first stage velocity.

[delta22]

Based on this info....the conclusion is obvious...MORE MOTORS!

For the next attempt in two weeks, an all C11 first stage to be able to stage quickly at 0.9 seconds and

51x motors in the first stage to provide 1.5x more first stage thrust and the same total impulse (as the first stage just fired)

so HellBoy 50 becomes the HellBoy 70

By accelerating a lot faster for half the time, will build into the flight plan a better positioning for the second stage event.

Other thing to change is to reduce fin area on the next booster to make rocket less overstable.

All other safety elements will be fully implemented again, including RC safety ejection charge.

So Bill, you get another shot at blowing up my rocket if it displeases you...er ..I mean flies off course...

But seriously, thank you Bill Spadafora for your help with this project.

[delta22]

Boris, your flights are inspiring. When I look at them, I want to add a ring of 24mm BPs around the central 38mm AP in the 4 incher I'm building.

I wonder if you can share more about your flash pan setup. In particular, I wonder about lighting the AP from an electric igniter and the BPs (or their flash pan) from the main motor's flame. This way if the main fails to start, I can avoid BPs ignition.

Ari.

Thank you. Inspired is the way I feel when I see the video of your amazing glider.

From a visual effect point of view, it will take a lot of BP motors to be visible next to a 38mm motor.

Pic 1: British Electric Thunderbird going up on a Cesaroni F30 White longburn + 10x 24mm BP motors
Pic 2: Soyuz on Cesaroni G125 + 16x 24mm BP motors (15x fired)
Both these flights all motors fired by high output cluster box and Rocketflite igniters. Fired the AP motors alone in other projects to to build confidence in their "instant-on" ignition.

Pic 3: Sirius Rocketry Saturn V on AMW J440 + 4x BP motors
Used a fast igniting big motor with some pyrogen added near igniter. Also rocket was too heavy (16 lbs) for the BP motors to fly, so they were for effect only.

Best approach is to use a very fast igniting AP motor, like many of the Cesaronis that have the pressed BP plug built in.

Quickmatch leading from the back (outside only) of the big AP motor into the nozzle of each BP motor should do the trick. A number of folks in England have done this successfully and posted some pictures.

Another possibility would be to use a timer to airstart the BP motors.

[troj]

Based on this info....the conclusion is obvious...

In the immortal words of Prof Hathaway...Up The Voltage

(I approve )

-Kevin

[Sully]

Based on this info....the conclusion is obvious...MORE MOTORS!

Was there ever any doubt that this conclusion would be reached? I see the natural progression of these projects culminating with Boris ordering pallets wholesale from Estes and going for another Carmack prize. I'm thoroughly enjoying following along: impressed, educated, and entertained all at once!

[iter]

Based on this info....the conclusion is obvious...MORE MOTORS!

Yay! More motors, more margin of safety, more smoke, go Boris!

Ari.

[billspad]

So Bill, you get another shot at blowing up my rocket if it displeases you...er ..I mean flies off course...

I bought this on eBay a few years ago and never thought I'd have a use for it.

[blackbrandt]

According to the Handbook of model rocketry, you can use a 12 gauge shotgun just as well...

[KennB]

I bought this on eBay a few years ago and never thought I'd have a use for it.

Two things, Bill.
1) When did you every buy something on ebay with the idea that you would have a use for it - other than having cool stuff in your basement for the club meetings? and
B) You'll have to get that calibration brought up to date if you plan on using it at a sanctioned launch.

[iter]

Thank you. Inspired is the way I feel when I see the video of your amazing glider.

From a visual effect point of view, it will take a lot of BP motors to be visible next to a 38mm motor.

Thank you for your encouragement Boris. This is the essence of this place, isn't it? Taking inspiration and learning from each other.

The photos in your post show the BP motors quite visibly, even on the 4+J Saturn.

Quickmatch leading from the back (outside only) of the big AP motor into the nozzle of each BP motor should do the trick. A number of folks in England have done this successfully and posted some pictures.

I like this idea. I wonder if you can point me to these people's posts. I'd like to see what they are doing.

The rocket I'm thinking of is very simple. It uses motor eject; no electronics onboard. The simplicity of a quickmatch appeals to me. It only lights the outboards if the main fires.

Ari.

[CarVac]

You may have to be careful of chuffs, though.

Also, even CTI motors still have a slight delay between the initial burst from the igniter (which may or may not ignite the quickmatch) and the pressurization of the motor.

[delta22]

This is the layout for the 51x C11 engines for the booster.

Provides clearance for the launch rail, marked "RB".

Also the three large sustainer fins will be positioned above the three motors that protrude the furthest.

Plan to reduce booster fin area to make this flight less overstable. Six small rectangular fins will be used this time.

[delta22]

Repaired the small zipper with 5 small build ups of thin slow epoxy.

Attached inter-stage coupler used previously to 51x C11-0 engines with a generous amount of 5 minute epoxy.

[delta22]

Tacked 6x rectangular booster fins on with CA then filleted with epoxy.

The flight this Saturday is going to be fun...

[iter]

Attached inter-stage coupler used previously to 51x C11-0 engines with a generous amount of 5 minute epoxy.

I think we know now the source of your flight difficulty! That hammer must weigh over 10 lbs!

Ari.

[Pantherjon]

Tacked 6x rectangular booster fins on with CA then filleted with epoxy.

The flight this Saturday is going to be fun...

MAN, that's a LOT of motors!

Fun indeed! Good luck on the launch! Remember, pictures and video or it didn't happen!

[delta22]

Weather is predicted to be favorable for the CMASS launch tomorrow in Amesbury, Massachusetts: sunny, 5-7 mph winds, mid 40s F.

HellBoy 70 is go for launch. All rocketry and camera batteries are charged / verified at full power.

Will be using my standard def Gearcam for onboard video plus 3 other cameras from the ground.

My son Paul and his associates will be doing some more flights for their TARC project.

Hopefully the predicted light winds will be favorable for all of our flights tomorrow.

[KennB]

HellBoy 70 is go for launch. All rocketry and camera batteries are charged / verified at full power.

Will be using my standard def Gearcam for onboard video plus 3 other cameras from the ground.

Boris, as a "lock the barn door after the horse is gone" suggestion, can you attach some streamer material to the onboard camera so we more easily find it if that becomes necessary. I'm hoping someone stumble across your camera from two weeks ago.

[delta22]

Boris, as a "lock the barn door after the horse is gone" suggestion, can you attach some streamer material to the onboard camera so we more easily find it if that becomes necessary. I'm hoping someone stumble across your camera from two weeks ago.

I appreciate your concern for the potential risk of losing another onboard video camera.

Good idea, will see what I can rig up.

[troj]

I appreciate your concern for the potential risk of losing another onboard video camera.

Good idea, will see what I can rig up.

1/2" orange plastic marker tape from a home improvement store should work beautifully -- the stuff they tie to the end of rebar, or other things they don't want people to miss.

-Kevin

[delta22]

Took another close look at the data from the HellBoy 50 flight two weeks ago and finally figured out why the acceleration was about 25% less (9Gs instead of 12Gs peak value) than the sim had predicted.

The actual motor burns were about 1.0 sec for the C11 and 2.1 sec for the D11 engines. Longer than the published Estes motor thrust curves, and longer than the estimations the sim was making.

So the motor burns were slightly longer and less hard thrusting than nominal.

With a heavy and overstable rocket in crosswinds, this made it more difficult for the rocket to be well positioned for second stage ignition.

[bobkrech]

HellBoy-70 was a spectacular success!!! A WOW flight!!!

Bob

[delta22]

The HellBoy 70 lifted off fast and straight at the CMASS launch this afternoon on a quiet rush of fire and smoke.

(pic 1+2): All 51x C11 motors in the first stage fired creating a column of yellow flame and white smoke, sending up the rocket up quickly reaching a peak acceleration of 16.9 Gs.

The second stage fired one second later, in a smooth quick transition (pic 3), firing 18 of 19 loaded C11 engines and reaching a peak velocity of 272 fps (185 MPH). (pic 3+4)

The data from the Raven is fun to have.

The first stage fell 20 ft from the pad, and the interstage coupler is in good enough condition to be re-used.