SpaceX Falcon Heavy

The Rocketry Forum

Help Support The Rocketry Forum:

gwh

Well-Known Member
Joined
Nov 25, 2016
Messages
73
Reaction score
14
Location
Kamloops, BC
Congrats on the flight! There was a lot of things that could have gone wrong there and yet you ended up with a totally successful flight of a really complicated model.

Your magnet attachment design is really unique, props for coming up with that solution. Do you do chute recovery on the side cores or tumble?


PS should this be in the scale sub-forum?
 

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
Congrats on the flight! There was a lot of things that could have gone wrong there and yet you ended up with a totally successful flight of a really complicated model.

Your magnet attachment design is really unique, props for coming up with that solution. Do you do chute recovery on the side cores or tumble?


PS should this be in the scale sub-forum?
Thanks. It was luck. A booster mount failed on the pad and we used super glue to fix it.

To your question: the boosters used the same reverse chute recovery as the 1st stage core (see
https://www.apogeerockets.com/education/downloads/Newsletter439.pdf)
 

gwh

Well-Known Member
Joined
Nov 25, 2016
Messages
73
Reaction score
14
Location
Kamloops, BC
Cool. I am really amazed at how much pop you get with the 0-delay motors to pop out both the nose cone and the rear eject chute. I might have to run 0 second delay motors on the next flight of my Falcon Heavy build. The boosters were supposed to just fall off but they hung on until their delays charges popped - I think due a pretty fast roll rate of the rocket.
 

Blast it Tom!

Well-Known Dweeb
TRF Supporter
Joined
Dec 30, 2019
Messages
1,357
Reaction score
1,051
Location
Pittsburgh
Congratulations indeed! I'm kinda doing a mini BAR here (1st build in ages, learning a bunch) and I'm skimming through thinking "this is a beginner's thread? I'll be lucky if i ever get this advanced!" Nicely done!
 

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
I got an unexpected chance to fly the Falcon Heavy again!

I learned there is a club called Sacramento Area Rocketry Group (https://sargrocket.org/) that organizes monthly launches only an hour’s drive away. So last month I drove out to Sacramento and met some really great people. The event was well attended with a total of 144 launches.

So with a lot of attention by the crowd and some skepticism by the club’s rocket inspector, the Falcon Heavy passed the pre launch inspection and was announced as a “heads up flight”…


This launch was a FAIL. But this is a SpaceX project! So failure is only a problem if we do not learn from my mistakes. We learned several lessons…

1) Failure of center core ignition. You can see that the (B6-0) booster engines are working but not the (E12-0) center core.

This significantly diminished the assent. But that allows us to observe a number of problems that might otherwise have remained hidden. This was a WIN!.

Failure analysis: Inspection of the center core igniter revealed a twist in the wire right at the head. The nicromium wire was fused where it touched, thereby shorting the igniter. This explains why the first launch countdown failed and a second countdown ensued…

Lesson learned: Use higher quality igniters with insulated wires for cluster launches. Quick Dip is not enough as a failure of this type would not have even turned up in a continuity check which I did not do.

2) An unplanned spin at launch.
The entire rocket rotated 360 degrees before the boosters separated. Had the center core ignited, I would have expected the ½ roll that actually happens in the Falcon Heavy launch. Which is what we saw on the first successful launch.

Failure analysis: I think this was an artifact of problem 1. That the boosters were doing all of the work and if the core had ignited the roll would have been over a much longer flight path than what was observed.

Lesson learned: There is a design flaw that could be hidden with this excuse. The lower booster mount is attached to the plastic section of the core rocket that holds the fins but is ejected when the core rocket reverse recovery happens. This means that the upper booster mount and the lower booster mount are not fixed in a line but can swivel with respect to each other because the bottom section separates from the main body tube in flight. I realize the defect much earlier but booster mounts and centering rings were all built to this specification and I figured I’d just live and learn until I had the chance to build version two.

3) An unplanned ejection of the left booster nose cone.

Failure analysis: One of my goals in this build was to embody the SpaceX idea of re-usability so the only parts that I glued together are 1) the engine tubes to the centering rings, 2) the booster mounts to the body tubes, and 3) the fins to the second stage. Everything else is press fitted using electrical tape to add diameter to parts to add friction.

Lesson Learned: Tape the outside of the nose cone to booster body. I did this on the Death Valley launch but forgot to this time around. I should experiment with vent holes too.

4) Incomplete booster separation. The right booster upper mount did not release


Failure analysis: The magnetic repulsion of the right booster upper mount failed. I think this is a combination of friction inside the mount, inadequate magnetic force, and issue 2 above, which could result in booster mount binding due to the twisting of the booster relative to the core in flight.

Lesson learned: Fix issue 2 and increase the magnetic power of the booster release. There is a related problem when moving the entire rocket assembly. The entire assembly needed to be handled carefully as the magnetic booster attachment is not very strong. The booster attachment also needs to be stronger.

Conclusion:
A second flight repeated all of the above problems (this time with the center core failing to ignite because of a bad igniter (lesson learned: check continuity) and a booster mount broke. But at least some things worked; like the rear ejection recovery of the boosters. And a third flight (without the boosters) was successful, including ignition of the (C6-3) second stage! The whole experience was a blast.

The next SARG launch is March 28th, hopefully I'll have all of these issues resolved and I can try again.
 
Last edited:

ThirstyBarbarian

Well-Known Member
Joined
Feb 11, 2013
Messages
9,346
Reaction score
2,313
Hey! I was there at SARG and watched these flights! They were entertaining in their own right, but I hope I can be there for the successful one when it happens. It looks like you've done a good analysis and are on the track to solving the issues. A different kind of igniter would definitely help quite a bit with lighting all motors simultaneously.

SARG is a great club, and a lot of us who fly with SARG also fly with LUNAR. Next LUNAR launch is Sunday March 8 (postponed from the original date of March 7 due to possible rain). The field is a gorgeous cattle ranch east of Stockton on Hwy 4, very close to Farmington. You might not have solved all the Falcon Heavy issues by then, but you might still want to check out the launch. It's a great club, there will be some epic high-power flights (including an L3 cert attempt M motor), and there are several people I know who have done similar booster separation projects like yours who you might want to talk to.

Here is the club website. https://www.lunar.org I know it still says the launch is Saturday, but it's not! Get on the LUNAR Announce email list to be kept in the loop on the most up-to-date info about launches, and always double-check the hotline before driving out.
 

aerostadt

Lifetime Supporter
TRF Lifetime Supporter
Joined
Oct 27, 2009
Messages
3,604
Reaction score
455
Location
Brigham City, UT
For Estes 24 mm BP motors I have switched over to e-matches (I have a ton of e-matches I bought from Blackjack.) and I put in place with that poster ticky-tack putty you can buy at stores. It works like a charm and prep time is quick. I have launched two clusters with six 24 mm BP motors each with no problem.
 

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
falcon heavy.PNG
I got an unexpected chance to fly the Falcon Heavy again!

I learned there is a club called Sacramento Area Rocketry Group (https://sargrocket.org/) that organizes monthly launches only an hour’s drive away. So last month I drove out to Sacramento and met some really great people. The event was well attended with a total of 144 launches.

So with a lot of attention by the crowd and some skepticism by the club’s rocket inspector, the Falcon Heavy passed the pre launch inspection and was announced as a “heads up flight”…


This launch was a FAIL. But this is a SpaceX project! So failure is only a problem if we do not learn from my mistakes. We learned several lessons…

1) Failure of center core ignition. You can see that the (B6-0) booster engines are working but not the (E12-0) center core.

This significantly diminished the assent. But that allows us to observe a number of problems that might otherwise have remained hidden. This was a WIN!.

Failure analysis: Inspection of the center core igniter revealed a twist in the wire right at the head. The nicromium wire was fused where it touched, thereby shorting the igniter. This explains why the first launch countdown failed and a second countdown ensued…

Lesson learned: Use higher quality igniters with insulated wires for cluster launches. Quick Dip is not enough as a failure of this type would not have even turned up in a continuity check which I did not do.

2) An unplanned spin at launch.
The entire rocket rotated 360 degrees before the boosters separated. Had the center core ignited, I would have expected the ½ roll that actually happens in the Falcon Heavy launch. Which is what we saw on the first successful launch.

Failure analysis: I think this was an artifact of problem 1. That the boosters were doing all of the work and if the core had ignited the roll would have been over a much longer flight path than what was observed.

Lesson learned: There is a design flaw that could be hidden with this excuse. The lower booster mount is attached to the plastic section of the core rocket that holds the fins but is ejected when the core rocket reverse recovery happens. This means that the upper booster mount and the lower booster mount are not fixed in a line but can swivel with respect to each other because the bottom section separates from the main body tube in flight. I realize the defect much earlier but booster mounts and centering rings were all built to this specification and I figured I’d just live and learn until I had the chance to build version two.

3) An unplanned ejection of the left booster nose cone.

Failure analysis: One of my goals in this build was to embody the SpaceX idea of re-usability so the only parts that I glued together are 1) the engine tubes to the centering rings, 2) the booster mounts to the body tubes, and 3) the fins to the second stage. Everything else is press fitted using electrical tape to add diameter to parts to add friction.

Lesson Learned: Tape the outside of the nose cone to booster body. I did this on the Death Valley launch but forgot to this time around. I should experiment with vent holes too.

4) Incomplete booster separation. The right booster upper mount did not release


Failure analysis: The magnetic repulsion of the right booster upper mount failed. I think this is a combination of friction inside the mount, inadequate magnetic force, and issue 2 above, which could result in booster mount binding due to the twisting of the booster relative to the core in flight.

Lesson learned: Fix issue 2 and increase the magnetic power of the booster release. There is a related problem when moving the entire rocket assembly. The entire assembly needed to be handled carefully as the magnetic booster attachment is not very strong. The booster attachment also needs to be stronger.

Conclusion:
A second flight repeated all of the above problems (this time with the center core failing to ignite because of a bad igniter (lesson learned: check continuity) and a booster mount broke. But at least some things worked; like the rear ejection recovery of the boosters. And a third flight (without the boosters) was successful, including ignition of the (C6-3) second stage! The whole experience was a blast.

The next SARG launch is March 28th, hopefully I'll have all of these issues resolved and I can try again.
I thought it would help to make this diagram.
 
Last edited:

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
Hey! I was there at SARG and watched these flights! They were entertaining in their own right, but I hope I can be there for the successful one when it happens. It looks like you've done a good analysis and are on the track to solving the issues. A different kind of igniter would definitely help quite a bit with lighting all motors simultaneously.

SARG is a great club, and a lot of us who fly with SARG also fly with LUNAR. Next LUNAR launch is Sunday March 8 (postponed from the original date of March 7 due to possible rain). The field is a gorgeous cattle ranch east of Stockton on Hwy 4, very close to Farmington. You might not have solved all the Falcon Heavy issues by then, but you might still want to check out the launch. It's a great club, there will be some epic high-power flights (including an L3 cert attempt M motor), and there are several people I know who have done similar booster separation projects like yours who you might want to talk to.

Here is the club website. https://www.lunar.org I know it still says the launch is Saturday, but it's not! Get on the LUNAR Announce email list to be kept in the loop on the most up-to-date info about launches, and always double-check the hotline before driving out.
Thanks for the tip regarding LUNAR! I attended and was impressed by everything and everybody. What a great event! And no I didn't have anything to lunch, but it was still fun to watch. I'll definitely be back!
 

ThirstyBarbarian

Well-Known Member
Joined
Feb 11, 2013
Messages
9,346
Reaction score
2,313
Thanks for the tip regarding LUNAR! I attended and was impressed by everything and everybody. What a great event! And no I didn't have anything to lunch, but it was still fun to watch. I'll definitely be back!
Great! I’m glad you made it out there. It’s a fun group of people, and we had some great flights. It looks to me like the land is drying out quickly this year. Once the grass starts turning brown they shut it down for the season for fire safety. So hopefully we get another launch in April, but May is almost certain to be out. Maybe I’ll see you later this month at SARG.
 

jondub

Well-Known Member
Joined
Mar 9, 2011
Messages
48
Reaction score
5
Location
Sacramento, California
I also saw both of your flights...pretty cool. Hope you can get all these complex processes working. I hope to fly our 1/24 scale Falcon 9 soon, probably Dairyaire, upgraded to Block 5 with a Crew Dragon capsule and trunk and try to create the abort test. Lots of complexity with just the F9...the Heavy is insane! Below is photo of our F9 flying at LDRS XXXVII at TCC.

upload_2020-3-10_8-43-53.png
 

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
I got an unexpected chance to fly the Falcon Heavy again!

I learned there is a club called Sacramento Area Rocketry Group (https://sargrocket.org/) that organizes monthly launches only an hour’s drive away. So last month I drove out to Sacramento and met some really great people. The event was well attended with a total of 144 launches.

So with a lot of attention by the crowd and some skepticism by the club’s rocket inspector, the Falcon Heavy passed the pre launch inspection and was announced as a “heads up flight”…


This launch was a FAIL. But this is a SpaceX project! So failure is only a problem if we do not learn from my mistakes. We learned several lessons…

1) Failure of center core ignition. You can see that the (B6-0) booster engines are working but not the (E12-0) center core.

This significantly diminished the assent. But that allows us to observe a number of problems that might otherwise have remained hidden. This was a WIN!.

Failure analysis: Inspection of the center core igniter revealed a twist in the wire right at the head. The nicromium wire was fused where it touched, thereby shorting the igniter. This explains why the first launch countdown failed and a second countdown ensued…

Lesson learned: Use higher quality igniters with insulated wires for cluster launches. Quick Dip is not enough as a failure of this type would not have even turned up in a continuity check which I did not do.

2) An unplanned spin at launch.
The entire rocket rotated 360 degrees before the boosters separated. Had the center core ignited, I would have expected the ½ roll that actually happens in the Falcon Heavy launch. Which is what we saw on the first successful launch.

Failure analysis: I think this was an artifact of problem 1. That the boosters were doing all of the work and if the core had ignited the roll would have been over a much longer flight path than what was observed.

Lesson learned: There is a design flaw that could be hidden with this excuse. The lower booster mount is attached to the plastic section of the core rocket that holds the fins but is ejected when the core rocket reverse recovery happens. This means that the upper booster mount and the lower booster mount are not fixed in a line but can swivel with respect to each other because the bottom section separates from the main body tube in flight. I realize the defect much earlier but booster mounts and centering rings were all built to this specification and I figured I’d just live and learn until I had the chance to build version two.

3) An unplanned ejection of the left booster nose cone.

Failure analysis: One of my goals in this build was to embody the SpaceX idea of re-usability so the only parts that I glued together are 1) the engine tubes to the centering rings, 2) the booster mounts to the body tubes, and 3) the fins to the second stage. Everything else is press fitted using electrical tape to add diameter to parts to add friction.

Lesson Learned: Tape the outside of the nose cone to booster body. I did this on the Death Valley launch but forgot to this time around. I should experiment with vent holes too.

4) Incomplete booster separation. The right booster upper mount did not release


Failure analysis: The magnetic repulsion of the right booster upper mount failed. I think this is a combination of friction inside the mount, inadequate magnetic force, and issue 2 above, which could result in booster mount binding due to the twisting of the booster relative to the core in flight.

Lesson learned: Fix issue 2 and increase the magnetic power of the booster release. There is a related problem when moving the entire rocket assembly. The entire assembly needed to be handled carefully as the magnetic booster attachment is not very strong. The booster attachment also needs to be stronger.

Conclusion:
A second flight repeated all of the above problems (this time with the center core failing to ignite because of a bad igniter (lesson learned: check continuity) and a booster mount broke. But at least some things worked; like the rear ejection recovery of the boosters. And a third flight (without the boosters) was successful, including ignition of the (C6-3) second stage! The whole experience was a blast.

The next SARG launch is March 28th, hopefully I'll have all of these issues resolved and I can try again.

So is it an option to start one motor which is mounted to the launch pad and use it to ignite the core and boosters simultaneously? So that one motor lights the next three? I'm thinking this is a "flash pan" technique...

This would solve the cluster ignition problem and be really cool.

falcon heavy launch mechansim.PNG


falcon heavy launch mechansim2 .PNG

falcon heavy launch mechansim 3 .PNG
falcon heavy launch mechansim 4 .PNG
 
Last edited:

Nytrunner

Pop lugs, not drugs
TRF Supporter
Joined
Oct 15, 2016
Messages
8,005
Reaction score
3,727
Location
Huntsville AL
Ive seen folks use quik-match or cannon fuze to light other motors with the ignition of the central core
 

neil_w

Tenet Rocketworks
TRF Supporter
Joined
Jul 14, 2015
Messages
12,500
Reaction score
5,435
Location
Northern NJ
I would wonder if a single 18mm motor could light three additional motors at a right angle like that. Would definitely require test and verification.

I think the single most amazing thing I've read in this thread is that you successfully flew a 1 lb rocket off a 1/8" rod. :)

Great work!
 

beeblebrox

8 C6-0, 12 D11-9, 20 D20-0, 20 E5-0, 3 Cinerocs
Joined
Mar 19, 2016
Messages
755
Reaction score
371
Location
West Chester, PA
I would wonder if a single 18mm motor could light three additional motors at a right angle like that. Would definitely require test and verification.

I think the single most amazing thing I've read in this thread is that you successfully flew a 1 lb rocket off a 1/8" rod. :)

Great work!
That should work just fine as long as the three motors in the Falcon are black powder, you also should add about 1/2 gram loose black powder under the three motors for the "Flash in the Pan" Make sure for each of the three motors in the rocket, find the largest drill bit that will fit loosely in the nozzles, and turning by hand make sure the top of the nozzle throat is cleaned of any nozzle clay from the manufacturing process. (This is not modifying the motors for all you nit pickers out there...) just cleaning out any residue that can impede ignition. As a cluster expert I have found many an Estes motor with a thin layer of clay up in there, which WILL impede ignition... One of thereasons I preferred core burners, they are easier to ignite... A10's, B8's, B14's, C5's, D20's, E60's, F100's

I am guessing from your drawings that your rocket is flying with C6's. D12's would be easier to light that way.
 

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
Version 2.0 ready to fly.

1: Lower booster mounts relocated onto the main BT-60 tube core tube. This required changing both body mount location and changing engine magnet mount location.
2: Doubling of the number of magnets in the boosters for more secure attachment and more energetic release.
3: All booster mounts milled to lesser tolerances to facilitate easier separation.
IMG_1455.JPG
 

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
Version 2.0 ready to fly.

1: Lower booster mounts relocated onto the main BT-60 tube core tube. This required changing both body mount location and changing engine magnet mount location.
2: Doubling of the number of magnets in the boosters for more secure attachment and more energetic release.
3: All booster mounts milled to lesser tolerances to facilitate easier separation. View attachment 414103
 

hermanjc

Well-Known Member
Joined
Jul 22, 2014
Messages
193
Reaction score
423
Location
Hudson, MA
Excellent build! I am late to the party on this one, but very happy to see the first flight was a success and even after some trouble with the second flight you got it back into flying shape. Were you able to get it out to fly again?

Do you happen to have the dimensions of the clear tail fins for your center core? I am doing a scratch build Falcon Heavy (BT-55 base tubes so probably about 6" shorter than yours) and am trying to size them appropriately.

I also have the boosters so they will hold motors for a 3 motor cluster launch configuration, but I was not as ambitious as you to also have the second stage take off. I have gone with an Apogee inspired home built booster release, but really like what you did with the magnets and bushings (it certainly helps you maintain the aesthetics of a true FH).

I look forward to hopefully seeing another launch of this one!
 

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
Thanks! Here in Northern California, the launch window is constrained by the fire season. And when the rains come, well, there's rain. So this bird won't fly until February or March 2021. That's how we ended up in Death Valley in November where it never rains and rocks don't burn.

The fins in the RockSim file are accurate:
fins.png


I'm looking forward to seeing your build.
 

hermanjc

Well-Known Member
Joined
Jul 22, 2014
Messages
193
Reaction score
423
Location
Hudson, MA
Thank you for the fin detail. I ended up having to add 2 fins to each booster after swing testing.

I finished and flew my FH three times this weekend with 2 good flights and 1 booster hang up that almost ended in a wreck. I have the details here:


Here's hoping to more successful launches to you in the future!
 

Switch

Well-Known Member
Joined
Nov 5, 2016
Messages
65
Reaction score
52
I put the next version of this build on the Low Power Rocketry forum:
 
Top