100,000' on M Power. Can it be done?

I have been asking myself this question to see if I can put a rocket up "on a budget."

I came up with this design, with a working name of the Black Rock Monster. A minimum diameter 3" booster connected to a minimum diameter 54mm second stage. Booster stage would be a CTI M1540 (6,809NS). Second stage would be a CTI L935 (3,076 NS). Total firepower, 9,985 NS. Electronics for staging would be in the booster section.

The rocket design and sims are below. Challenges: 1) stability at time of staging. 2) keeping a CF rocket together at Mach 3.9. 3) Effectively keeping 2 minimum diameter stages together at speeds up to Mach .9

THis is all hypothetical at this point. I don't have the time or money to build it. But it is a cool challenge.

What happens with a K300 instead?

Jim

How do you get Mach 3.9? I assume your velocity is in ft/s which put's you in the mid to high Mach 2 range.

Wow Evan,

When you launch this in Nevada I hope to be there watching.
It's an ambitious project and will follow this thread.
See you at MARS in Geneseo next week.

I wonder what an M840 to an L265 would sim to?

EeebeeE said:

Electronics for staging would be in the booster section.

Click to expand...

Your sim shows a 5-second delay between stage separation and second-stage ignition. You'll find that hard to implement with the electronics in the booster.

I'm also not clear on how your design holds the stages together.

I looked something similar a few months ago but in a 3" => 38mm configuration (kinda like a boosted dart but with a motor in the dart too) since I have existing rockets which could be used to make the stack. I simmed with an M2020 to J530 which stays below M3.

100K looked possible under ideal conditions. The problem is getting ideal conditions - like no jet stream at middle altitudes and keeping the sustainer vertical during a long coast between stages to get optimum altitude.

Ravenex said:

How do you get Mach 3.9? I assume your velocity is in ft/s which put's you in the mid to high Mach 2 range.

Click to expand...

His plot says velocity in mph not ft/s.

A pure boosted dart ought to do it easily. The NASA Super Loki Dart of the 1960's was basically a large HPR sized vehicle (4" motor a few feet long, maybe an N) and went well over 200 kFt. You use a high thrust motor to get it up to the max feasible velocity (the Loki reached about Mach 5 IIRC). The booster then drops away leaving the fully streamlined, zero-base-drag dart to coast upwards. With the altitudes reached by the Loki they had to spin it up at launch using a spiral launch tower since the fins on the dart became ineffective at altitude. If you're only targeting 100 kFt you probably don't need to spin it. The pure dart can go a lot higher than a powered 2nd stage because of the elimination of base drag.

caveduck said:

The NASA Super Loki Dart of the 1960's was basically a large HPR sized vehicle (4" motor a few feet long, maybe an N) and went well over 200 kFt.

Click to expand...

9000 N thrust for 1.9 seconds, so 17100 N-s total impulse, or yes, a fairly large N.

caveduck said:

A pure boosted dart ought to do it easily. The NASA Super Loki Dart of the 1960's was basically a large HPR sized vehicle (4" motor a few feet long, maybe an N) and went well over 200 kFt. You use a high thrust motor to get it up to the max feasible velocity (the Loki reached about Mach 5 IIRC). The booster then drops away leaving the fully streamlined, zero-base-drag dart to coast upwards. With the altitudes reached by the Loki they had to spin it up at launch using a spiral launch tower since the fins on the dart became ineffective at altitude. If you're only targeting 100 kFt you probably don't need to spin it. The pure dart can go a lot higher than a powered 2nd stage because of the elimination of base drag.

Click to expand...

It's not quite that simple.

1.) The booster motor for the Super Loki Dart was equivalent to a 37874 O 17893 hobby motor, not an M. The booster weighed 50.87 pounds and contained 37.51 pounds of propellant with an Isp = 232 seconds, all in a 4" x 78" casing! The empty booster casing was unstable and tumbled immediately on separation. This slowed the casing down extremely fast and limited the ballistic range of the booster.

2.) The Super Loki Dart weighed 18.25 pounds and was 2.125" OD. The sectional density was 5.15 pounds per square inch, or 11 times greater than a 0.50 caliber bullet! It was built out of steel, not aluminum and was coated with ablative to withstand the enormous heat load of Mach 5 flight in the lower atmosphere! The original Robin Dart was about the same size as the Rocketry Warehouse Go Devil 38 but was 16X heavier. A dart base drag is ~5x lower than a flat base due to the boat-tail design, but the extremely long coast time is due to the extremely high sectional density, and the resultant retained momentum due to the very high mass.

3.) The launcher imparted a 8.5 rps spin to the rocket and dart. Without spin the apogee would be significantly less to due to asymmetry in the CG and aerodynamic forces which cause an enhanced gravity turn and a trajectory moving towards horizontal. Any long skinny rocket will have a tendency to turn to the horizontal unless it is spinning rapidly to average out inertial and aerodynamic asymmetries.

Bob

A couple answers to questions and other feedback.

Velocity was measured in MPH

Currently have not thought of a good method to hold stages together. Open to ideas.

Question on the boosted dart. What if the dart was held onto the nose of the booster stage with a long aluminum rod with the aft end of the dart having a tube in which that rod would fit into? At separation, a 1 gram BP charge inside the tube would fire, effectively goosing the dart and propelling it forward. Below is a design. Unfortunately, OR will not sim the dart's flight without a motor put into it.

EeebeeE said:

A couple answers to questions and other feedback.

Velocity was measured in MPH

Currently have not thought of a good method to hold stages together. Open to ideas.

Question on the boosted dart. What if the dart was held onto the nose of the booster stage with a long aluminum rod with the aft end of the dart having a tube in which that rod would fit into? At separation, a 1 gram BP charge inside the tube would fire, effectively goosing the dart and propelling it forward. Below is a design. Unfortunately, OR will not sim the dart's flight without a motor put into it.
View attachment 267645

Click to expand...

Maybe you could try putting a 1/2A or whatever in the dart to get it to simulate its flight?

Ok, a couple thoughts just looking at the pictures.

If I could I would make the boosted dart shorter and smaller in diameter. You want the booster to get to speed and drag separate so you need a fair amount of diameter difference.

To simulate the flight, put a 1/4 A or something in it. Essentially no effect as the impulse is next to nothing in comparison to everything else going on. Yet, that tiny motor will allow the sim to see another motor hence stage.

If you optimize the mass of the dart, it will separate in its own. And you won't be using streamer recovery, it will be heavy.

I tried to optimized a design in a sim for a 3" M to a 38mm dart, the first 12 inches of the dart would have had to been made of solid steel. Good luck with recovery.

I tried using an A10, but it would still not record the altitude of the dart. Interestingly enough, there is a curve for it, but it goes off the chart.

The dart design is 38mm. The aft tube is 13mm. Constructed of FG. Mass is about 2.5 to 3 lbs. Was thinking about a 10' x 4" mylar streamer. Could deploy a main chute as well.

EeebeeE said:

I tried using an A10, but it would still not record the altitude of the dart. Interestingly enough, there is a curve for it, but it goes off the chart.

The dart design is 38mm. The aft tube is 13mm. Constructed of FG. Mass is about 2.5 to 3 lbs. Was thinking about a 10' x 4" mylar streamer. Could deploy a main chute as well.

Click to expand...

I could be wrong but I don't think you will get more than 40,000 ft AGL from the dart.

Bob

To answer your original question "Can it be done?", my guestimate is yes, or a minimum you can come close and set a TRA M altitude record.

https://aeropac100k.insaneprojects.com/data/AeroPac 2012 100k' Program Report.compressed.pdf is the report of the aeropac100K project which won the Carmack prize using a 4" booster and a 3" sustainer with a total installed impulse equivalent to a 6% O motor. By using a 75 mm booster and a 54 mm sustainer, you should be able to reduce the total impulse required by ~50%, and by using higher impulse motor, reduce the gravity loss and the gravity turn that can occur under powered flight, so that you could equal the 100K apogee with a 95% M equivalent motor. The choice of the CTI Pro75 6819M1540 (18 G peak acceleration) is much better for a straight boost as is the CTI Pro54 3147L935 (39 G peak acceleration) sustainer. I might even suggest looking at the CTI Pro75 6800M3700 (34 G peak acceleration) as the booster motor as it has a 200 fps advantage at booster burnout.

Quick modeling indicates your airframe weights might be a bit optimistic. I used a 7 pound booster rocket (w/o motor) and a 3 pound sustainer rocket (w/o motor). The rocket would have a lift-off weight of 28.5 pounds and a sustainer weight of 8.62 pounds. With the M1450 I get a delta-v = 1574 fps and with the M3700 a delta-v = 1779 fps, and with the L935 the sustainer has a delta-v = 2262 fps. The combined delta-v should be enough to apogee at 100K if the drag is minimized and the coast times optimized. Certainly if it doesn't break 100K, it will definitely set a M-impulse altitude record.

I referenced the 100K Aeropac document particularly because of their modeling and their inter-stage coupler design which is very good and worth copying. I don't see the need for CO2 deployment if hermetic sealed charge wells are used. With proper construction techniques, the project does not stretch any technology barriers as the rocket will only briefly exceed Mach 3 so the thermal environment is rather mild for a properly laid-up carbon composite.

Well thought out.

Bob

Evan,

OpenRocket should be able to simulate the motorless dart just fine. There's an example of exactly that in the File->Examples menu.

Post your full ork file and I'll poke into it a little.

Kevin

EeebeeE said:

A couple answers to questions and other feedback.

Velocity was measured in MPH

Currently have not thought of a good method to hold stages together. Open to ideas.

Question on the boosted dart. What if the dart was held onto the nose of the booster stage with a long aluminum rod with the aft end of the dart having a tube in which that rod would fit into? At separation, a 1 gram BP charge inside the tube would fire, effectively goosing the dart and propelling it forward. Below is a design. Unfortunately, OR will not sim the dart's flight without a motor put into it.
View attachment 267645

Click to expand...

Here are both ORK files. Feel free to work with them.
View attachment Boosted Dart.ork View attachment Black Rock Monster.ork

Friends I fly with will tell you I like to push the envelope. Problem is in the Eastern US we don't have very high waivers so I haven't had the chance to really make one go. I did send one to a simmed altitude of 19,000+ feet at LDRS. Transmitter croaked at launch. I understand it may have been found, and it will be cool to get the telemetry data. Its peak speed was just under Mach 2. FInal weight was about 8-10% higher than OR estimates.

I've seen some configurations with a high avg. N-S motor as the booster, then a long-burn as the second stage. I think you get less coast, which in this case, is going to be more important. Question: Can the M record be set with a 2-stage as long as it stays under 100% M?

For Tripoli there are two separate records - single motor and staged.

EeebeeE said:

Question: Can the M record be set with a 2-stage as long as it stays under 100% M?

Click to expand...

I believe TRA has a class for single M motors and a separate class for M multistage. The TRA website is a bit confused at the moment, or I have to log on to find the record info to be certain.

mikec said:

The TRA website is a bit confused at the moment, or I have to log on to find the record info to be certain.

Click to expand...

They haven't migrated the records page over to the new infrastructure yet.

Staged M, 44961
https://www1.tripoli.org/Membership/CompetitionsandRecords/MStagedMotorRecord/tabid/307/Default.aspx

M

Evan,

The latest OpenRocket available here when sourceforge comes back online, can simulate the dart well. I do see some weirdness because when I graph it, the stage selector seems to have the two pieces confused. I'll look into that.

Kevin

I played around with the staging settings and time delays. Briefly got it to read a separation and dart altitude, but in trying to check to see if I could sim it higher, I lost the settings. At any rate, the highest altitude I could sim the dart was to 37,000' or so. I do not believe a boosted dart can go near 100,000' unless there is a lot more force behind it.

kruland said:

Evan,

The latest OpenRocket available here when sourceforge comes back online, can simulate the dart well. I do see some weirdness because when I graph it, the stage selector seems to have the two pieces confused. I'll look into that.

Kevin

Click to expand...

There's a mirror, or you can grab the sources from github and compile them. No ETA yet from SF.


https://www.mirrorservice.org/sites...sourceforge/o/op/openrocket/openrocket/15.03/

Well that doesn't help. I already have that version of OR. I think it needs to be fixed.

EeebeeE said:

I do not believe a boosted dart can go near 100,000' unless there is a lot more force behind it.

Click to expand...

Evan, what was the mass of the dart? It has to be very heavy to get altitude. Think bullet not rocket for that piece.

That made a difference. The rocket stays at about Mach 2.5, but the inertia and momentum generated by having 5 lbs of mose weight in the dart makes it go hig. Not to 100,000', but pretty high. THe sim shows right at about 60,000'.

This is the reconfigured dart. The line from the top of the nose cone back represents the ballast.
View attachment Boosted Dart.ork

And this is the simmed flight.