Once again, thanks so much to today's sponsor for their generous support - please check out the link they provided! bps.space/products/bps-whos-in-charge-here
Place the drive shaft on the upper end of the test fin so that the driving forces will be smaller to keep the fins aligned but greater to rotate... I believe that this way the chances of erratically moving the fins would be smaller, even less with failure of the mechanisms (PT-BR: Coloque o eixo de movimentação na ponta superior da aleta de comprove assim as forças motoras serão menor para se manter as aletas alinhadas porem maiores para rotacionar... Acredito que assim as chances de movimentos das aletas de forma erráticas seriam menores menso com falhas dos mecanismos
What about hall effect sensors on the body of the rocket with a few small magnets embedded in the fins? This could give you fin position independent of the servo position in relation to the body.
I presume that was the "big sugar engine" that threw out all the streamers (isn't that the Official Name for those things?). It sounds like a DIY engine - had they not tested the design, preferably several times? Do they have a channel or blog where I can follow what they're doing (not that I want to dedicate my life to watching amateur rocketry)?
@@TranscendentBen I think this engine is so big they wanted to test it in the desert and not at home. So nice they did it in a dessert and not at home.
Hi from Space Enterprise at Berkeley! I didn't get to go out there this time but I hope you were able to meet some of our team! When you put "idk what to put here" I felt that sooo much too hahaha especially with what I'm working on, even numbers of things helps a lot
There are a couple things that I see that could be changed resulting in a more successful flight test. 1. Bring the hinge for the fins further forward to take some of the “snap” away from the fins at aggressive AOA. 2. Update servo horn from plastic/nylon to a aluminum arm. maybe use 440 rod with ball links. Do not use piano wire and z bends and glue, the aerodynamic forces will be too great and the setup has a lot of slop if glue fails. 3. Limit the travel of the fin or use a expo curve to soften the movement as velocity increases. Slowly increase deflection each flight (All knowledge is from time as a RC builder and pilot not to oversimplify but this is the same control method as RC aircraft)
I second everyone of the suggestions! Ball-links with rigid arms are definitely the way to go. At 100m/s+ there’s some serious aerodynamic loads there.
Add some led etc it shows to video synchronous driving fin motors and fins leading edge profile in my mind is too thick. Looks only by video, that driver overdrive after it didn't get clear imagine from gyro from early start. Test that rocket in hand how it reacts,and I think you have been done that numerous times. Good video and nice to see hobby live so nicely by others too
Dito on the hinge placement...I came here to comment the same thing. Right now it's an unstable system. If you move the hinge up, the fin will tend to stay in-line withe the direction of travel.
Yup, you are totally on point. I’m also a long time RC builder and have done many full flying tails on high performance aircraft. You need the hinge point around 20-25% MAC (mean aerodynamic chord) to be in front of the center of pressure. Also make sure the servo linkages have zero slop to minimize flutter. Also make sure the control throw is such that the endpoint deflection is close to the max throw of the servo so you have the best resolution and high mechanical advantage (think highest torque and high resolution).
No modern car or truck should ever be run under a quarter tank if you want your vehicle to last as that fuel lubricates and cools the in-tank fuel pump!
@@Görkem-x5h But if your car breaks down all the fuel isn’t going to help you. Water is handy in plenty of situations (and if it’s just being stuck in a traffic jam for a few hours).
Torquing on the fin pivot point tends to create an ossolation that is difficult to dampen. Put a control pin near the front of the fin and cut a slot in the servo wheel to drive it.
Love the video! In the spirit of youtube, I know nothing about this topic, but here's my opinion/suggestion: I agree with this. Separating the rotation point from the actuation mechanism may let you get better mechanical advantage for fin movement while the extra rotational constraint from having two links to the fin would spare your rotation point from hugemongous forces. Challenges, of course, would include servo positioning, but that's a minor detail. ;)
I almost clicked away when you said sponsor. That company seems pretty nice. Also, I thought the flight went pretty well. Flew up, wiggled its fins and had parachute deployment.
My dad worked on rocket guidance systems for General Dynamics starting in the late 1950’s to the mid 1980’s. One system he talked about, he called “dithering” where the fins shook at a small angle with a certain rate, when they wanted to change direction they would just pause at one or the other angles +/- then back to shaking/dithering. You could possibly use electromagnet switching to get rid of the mechanical linkage?
Here’s a good start. Rocket engines are usually a pretty close guarded secret for the manufacturers. Tim Dodd has this latest video: ruclips.net/video/Y-xyXDiC92s/видео.html
Ok I usually never comment but the RUclips algorithm NEEDS to know this is the stuff I'm looking for. I've been following you for more than a year! 10/10 👍
I love how this started off like a documentary and ended like a good old BPS Space video with Joe doing something goofy, Can we have more of this is awesome :-)
"Launching rockets in the Mojave makes you wish for a nuclear winter." Man, it's beautiful out there. And so many folks working on their passions that there is a dedicated site to do so. I didn't know such a place existed. Very cool! I really enjoyed the video, Joe. Thanks!
I really appreciate the use of Subnautica music with your video. Love it! Would the rocket perform better if you have moving flaps on the back of the fins vs having the whole fin actuating?
You have a very interesting problem here with the PIDS. You will either need to write an algorithm to adjust the PIDS over the flight during powered lift or when you are flying at low speed you will have no issue as illustrated then when the speed picks up and the controls become super effective your algorithm will overcorrect and it will freak it out. I would say redesigning the fins to move the actuation point all the way to the back and the pivot to the very nose of the fin. Gets the best Mechanical Advantage at high speed and provides better servo precision. Then either go for full-on speed for the tune only or sacrifice high-speed control unless you can switch the rates between the two. Then the rocket looks like it should be great!
Amazing video Joe!! Cant wait to see the next flight of Fineas!! Loved the new concept of aerodynamic guidance and also loved the new way of vlog type coverage!
I think having the fins mounted to the servo is a weakness. Have a passive pivot point at the leading edge, but drive them laterally from as close to the trailing edge as possible for better leverage and stability. Yes, I mean having the linkage exposed. Great video, thanks.
FAR is such a great place for experimental rocketry. Those guys out there are always great. If you're ever doing anything with canards, the solid rocket team at San Diego State University has flown and the liquid team is planning to fly a rocket with forward control surfaces.
Amazing video! A few months ago, I thought about creating a fin controlled model rocket, but didn't see too much content on such a goal being achieved. I gave up on that project before I even started it. Now, with this video recently being released, I plan on pursuing this project again and learning as you go along! Can't wait to see the progress that is made along the way!
I was see on the Advanced Model Rocket site that sugar motor explosion , and was not expecting you was next to it , amazing , jut be safe. Wery cool that your rocket survived that blast.
The real question after the failure is actually what parts resolidified after cooling. The launch video does show the failure almost at maximum altitude, the fins ( what little action/reaction there was ) looked good until melt slipage. Option 7) Replace all linkage/parts with milled metals/carbonfiber and overkill the design, then fly again with the same flight program.
Congratulations Joe - as a test engineer I love every bit of this video :) - well, apart from the bit where you ask vulnerable people to pay to become an intern, that smacks more of that other guy you don’t want to be 😂 But seriously, your camera tracking rocks, you have telemetry and live flight cam, parachute is fine and you survived the attack of the Sugarmonster! Onwards and, of course, upwards!
First idea out of my head remembering V-2's... don't move the whole fin. Try hard mount main fin with servo driven tail flaps. Also check directionality of motion with the directionality of the servo rod movement. Pull, not push. Pushing the rod will bend fighting aerodynamic forces. If it needs to operate in both planes of motion use dual rods. Use metal geared servos against such high aerodynamic forces. Also suggest hinge be multi-sectioned (Like piano hinge) with 50 percent of total hinge width pins. (Note: during fin construction, bend pin ends over on both ends into slots top and bottom of flap, glue in place.) Leave space for vibration of flap. Even though you think the fin will be solid to the fuselage, vibration will close the flap gap and the flap will rub on the tube. I missed the build video for the rocket. Building a chassis for the servos to sit in that is much more stable than just mounting to a bulkhead. Next I'd limit the movement to 11.75 degrees in each direction. At the Max-Q speeds your rocket is flying, you don't need much deflection for roll control.
im kinda new to this sort of thing, but i would recommend 3d printing a tray for the servos that you could epoxy into the fuselage of the rocket, but overall awesome concept and I hope to see more.
Holy crap! I've been out in the Mojave doing geophysical survey work for the past month, and am about to head out tomorrow for another three weeks in the desert. Are you guys planning on more tests in that time frame because I'd love to be able to spectate live if you are. Also, my team were all wondering what those explosions were, now I can't wait to tell them what was going on. :)
Hey, Joe. First off, thank you for having the stones to post not just your many successes, but your failures as well. Not everyone has the ability to do that and you deserve thanks for doing so. Ok, secondly…. On mounting your fins. How about mounting the fin to a very small flat piece of aluminum that exactly matches the portion of the fin closest to the body of the rocket? Then you could weld a little shaft onto the plate and pass it thru a bearing or some type of seal/bushing that could keep it in the correct orientation and not allow it to wobble around once the air pressure against it increases during the launch event. I would also consider mounting the fins to the plates by screwing them from the shaft side and use some kickass epoxy or other adhesive of your choice. Having the metal control shafts would let you connect them to your servo horns (which it sounds like you are going to be replacing with aluminum for the next flight!) and eliminate any plastic or other parts that could potentially pose a risk of failure in high temp situations. Just think if you were to try and fly that thing in July or August down there in So Cal… it may have just melted right there on the rail! This is almost December so there are not many better weather patterns being offered by Mother Nature than what you were given. I learned my lesson with non metal servo horns when I was racing my 3D printed catamaran. My steering servo horn stripped the little teeth around the output shaft of the servo (who puts a metal geared high torque servo together using a plastic servo horn? Um, ahem, err, ok besides me I mean?) during a high speed run which did not end well when it failed suddenly and very completely…. 70mph into a stone wall at the edge of the lake. Wall vs 3D Boat. Wall 1, Boat nil.
It seems to me a control surface on the back of a fixed fin would be a bit more robust solution and have a much less wild failure mode. But I've only flown subsonic.
Interesting idea! The fin deflection should in my opinion be limited to something like maybe 5° and the pivot could maybe be altered to 2 points one being the aft hinge point and a ring conector which is connected to all the fins near the leading edge one servo or gear would turn the ring connector. The ring would be centered by 3 or more small cartrage berrings to keep friction minimized. These are my 2 cents, keep them or toss them that is your choice. CAR cert 3, NAR cert 2 DE VE9GIS
Good rocket, good flight, good video! One idea is that if you're doing more flights out in the hot desert, do a radiant heat test to ensure that this doesn't happen again and that everything else can withstand the desert sun Which is to say, stand the rocket up, stick a temperature sensor in it, get some cheap heat lamps, point them at the rocket, get it nice and hot, and see if anything fails or melts or gets soft that shouldn't
i find it funny that my immediate mental solution to the plastic bits softening was to have a reflective foil blanket over that part of the rocket that would fall away at launch. your solution is much, much more practical and actually would work.
Reduce aerodynamic forces on servos and links by using control surfaces on fins instead of using "flying" fins. Also, why such aerodynamically terrible fins instead of 3D printed airfoils?
Doesn’t this present issues in transonic and supersonic regimes because the shock wave is pushed behind the control surface? It’s why the bell x-1 and other moved to stabilator vs elevators. Just spit balling here
My thoughts as well. Perhaps don't run before you can walk - just use fixed fins, control surfaces on those fins and move said control surfaces using well-known servo/rod/horn setups taken from R/C aircraft. Sure you're going to struggle once you hit transonic speeds, but this thing is doing about half that at best. The control pin idea mentioned elsewhere in the comments also sounds like a good way to go.
I agree with this and more (!). I've been thinking, why do they even need to move more that 5 degrees or so - more than that and it's too easy to make it do what happened, make the rocket turn 90 degrees to the direction of travel. Is the eventual idea to go supersonic on this design? I recall Chuck Yeager being surprised at how the controls were operating around Mach 1 and how it almost surely contributed to previous test pilots' crashes. I'm "presuming" a lot here, that the fins are programmatically kept straight until after the rocket has left the launch tower, and so many other things I just now forgot. We all want Joe to succeed, and I'm hoping our comments are helpful and welcomed.
The transonic issue can be eliminated when he does scale up by articulating the outboard portion of the fin rather than the trailing edge, or using separate control fins like many missiles do, usually on the nose which leaves the rear volume for propellant and all the servos and controller in the nose.
I know this is late, but what about a synchronizer ring to position the fins? This is a mechanism used by variable vane turbochargers. You could position the ring towards the bottom of the rocket, allowing a forward hinge point, but drive it with something like a stepper motor from further up.
This has got to be the coolest channel I subscribe to. Any channel that can genuinely make me excited by saying "and now it's time to review the data" is definitely doing something right. I'm so excited to watch you find and overcome all the challenges in fin control. So cool. One question: Even though the fins failed, can you tell if the control system was working by comparing the roll-rate measurements with the control system outputs? I.e. would it have worked if the fin joints has not failed?
For your fin stabilization, would you consider a fin layout similar to an AIM-54 or AGM-65 where the large fixed forward fins do the majority of the neutral stability and the guidance fins are there for fine control? Another option would be to model the "Rollerons" that are found of the AIM-9 family of missiles. This is a passive control system that uses air speed to turn gyroscopes that are built in to control surfaces. My suggestions would be to have four fins working the pitch and yaw, as those two axis will require a considerable amount more control input than the roll axis. For the roll axis, I would limit the controls to be less than one third of the deflection the pitch and yaw receive, as well as maybe limiting the controls to two fins.
Have you thought of using a small barrel that rotates along the fuselage and to which all the fins would be attached? This and a fixed pivot on another part of the rocket would give the rocket rotational stability and prevent the possibility of failure as only one servo would be needed.
really freaking cool hobby you have here man, would be awesome to see you launch one of these and talk to you after about it. Rarely do you get to see someone with this much drive, talent and intellect create amazing things step by step but let alone in person. Looking forward to purchasing your flight computer and taking my small rocket hobby to the next level!
Maybe you can consider putting the fines upper on the rocket? I mean if you locate the servos and the fins right beneath the circuit boards, it might not get all that heat and still do the work.
Once again, thanks so much to today's sponsor for their generous support - please check out the link they provided! bps.space/products/bps-whos-in-charge-here
IM GONNA BE AN INTERN!!
So, this is like, an unpaid internship taken to its logical conclusion. I interned at BPS, and all I got was the chance to pay for this shirt :-D
Place the drive shaft on the upper end of the test fin so that the driving forces will be smaller to keep the fins aligned but greater to rotate...
I believe that this way the chances of erratically moving the fins would be smaller, even less with failure of the mechanisms
(PT-BR: Coloque o eixo de movimentação na ponta superior da aleta de comprove assim as forças motoras serão menor para se manter as aletas alinhadas porem maiores para rotacionar...
Acredito que assim as chances de movimentos das aletas de forma erráticas seriam menores menso com falhas dos mecanismos
hahaha now that I saw it... everyone had the same impression
What about hall effect sensors on the body of the rocket with a few small magnets embedded in the fins? This could give you fin position independent of the servo position in relation to the body.
that explosion was so cool, poor guys, it was like ava's first flight
What was that explosion
@@bracloop3178 Looks like the "Big sugar motor" blew up.
I presume that was the "big sugar engine" that threw out all the streamers (isn't that the Official Name for those things?). It sounds like a DIY engine - had they not tested the design, preferably several times? Do they have a channel or blog where I can follow what they're doing (not that I want to dedicate my life to watching amateur rocketry)?
@@TranscendentBen I think this engine is so big they wanted to test it in the desert and not at home. So nice they did it in a dessert and not at home.
You spoiled the result for me. I saw your comment in the little single comment preview thing before the launch.
Great video! Your production value is awesome.
Thanks Bobby
🤩🤩🤩😀😀 BIG FAN SIR
Hey thats another thing you guys have in common, apart from being part-time comedians ;)
hi
@@BPSspaceim making a rocket because of u
Hi from Space Enterprise at Berkeley! I didn't get to go out there this time but I hope you were able to meet some of our team!
When you put "idk what to put here" I felt that sooo much too hahaha especially with what I'm working on, even numbers of things helps a lot
Congrats to you and the team on having two great hot fires that day!! The LEDs on the test stand are awesome :)
Space Enterprise, here's a video of your second test fire ruclips.net/video/LPHrka9lM4Q/видео.html
There are a couple things that I see that could be changed resulting in a more successful flight test.
1. Bring the hinge for the fins further forward to take some of the “snap” away from the fins at aggressive AOA.
2. Update servo horn from plastic/nylon to a aluminum arm. maybe use 440 rod with ball links. Do not use piano wire and z bends and glue, the aerodynamic forces will be too great and the setup has a lot of slop if glue fails.
3. Limit the travel of the fin or use a expo curve to soften the movement as velocity increases. Slowly increase deflection each flight
(All knowledge is from time as a RC builder and pilot not to oversimplify but this is the same control method as RC aircraft)
I second everyone of the suggestions! Ball-links with rigid arms are definitely the way to go. At 100m/s+ there’s some serious aerodynamic loads there.
Add some led etc it shows to video synchronous driving fin motors and fins leading edge profile in my mind is too thick.
Looks only by video, that driver overdrive after it didn't get clear imagine from gyro from early start. Test that rocket in hand how it reacts,and I think you have been done that numerous times. Good video and nice to see hobby live so nicely by others too
Dito on the hinge placement...I came here to comment the same thing. Right now it's an unstable system. If you move the hinge up, the fin will tend to stay in-line withe the direction of travel.
Yup, you are totally on point. I’m also a long time RC builder and have done many full flying tails on high performance aircraft. You need the hinge point around 20-25% MAC (mean aerodynamic chord) to be in front of the center of pressure. Also make sure the servo linkages have zero slop to minimize flutter. Also make sure the control throw is such that the endpoint deflection is close to the max throw of the servo so you have the best resolution and high mechanical advantage (think highest torque and high resolution).
If you choose to remain with a single point mounting system put the pivot forward of the center of the fin so it zeros to straight ahead!
0:05 So never go above half full, got it! thanks!
No modern car or truck should ever be run under a quarter tank if you want your vehicle to last as that fuel lubricates and cools the in-tank fuel pump!
I’d rather take a lot of water into the desert than fuel.
@@Mike-oz4cv you can get out of desert with fuel but you can't do that with water.
@@Görkem-x5h But if your car breaks down all the fuel isn’t going to help you. Water is handy in plenty of situations (and if it’s just being stuck in a traffic jam for a few hours).
Ha, well spotted, I missed that first time round.
Where is Pherb tho?
Torquing on the fin pivot point tends to create an ossolation that is difficult to dampen. Put a control pin near the front of the fin and cut a slot in the servo wheel to drive it.
Love the video! In the spirit of youtube, I know nothing about this topic, but here's my opinion/suggestion: I agree with this. Separating the rotation point from the actuation mechanism may let you get better mechanical advantage for fin movement while the extra rotational constraint from having two links to the fin would spare your rotation point from hugemongous forces. Challenges, of course, would include servo positioning, but that's a minor detail. ;)
I almost clicked away when you said sponsor. That company seems pretty nice.
Also, I thought the flight went pretty well. Flew up, wiggled its fins and had parachute deployment.
Yeah, and I was wondering where's the Official Notice that this is a Sponsored Video ... the FTC or whoever it is "requires" those things nowadays ...
My dad worked on rocket guidance systems for General Dynamics starting in the late 1950’s to the mid 1980’s. One system he talked about, he called “dithering” where the fins shook at a small angle with a certain rate, when they wanted to change direction they would just pause at one or the other angles +/- then back to shaking/dithering. You could possibly use electromagnet switching to get rid of the mechanical linkage?
Hey dude where can I get practical knowledge about how combustion chamber is made?
Here’s a good start. Rocket engines are usually a pretty close guarded secret for the manufacturers. Tim Dodd has this latest video:
ruclips.net/video/Y-xyXDiC92s/видео.html
@@PiyushSingh-em5vz Look for a book called Rocket propulsion elements by George Sutton.
@@AIM54A what type of knowledge can I get from that book?
@@PiyushSingh-em5vz Elon Musk did ok.
THAT WAS AWESOME! I hope the next flight goes all right!
Well, unless you can control the pitch, then you go all left too if you want, idk
Olha ai o pesterenan aqui
The subnautica soundtrack in the intro caught me off guard :)
Me too !!! XD
same
Ok I usually never comment but the RUclips algorithm NEEDS to know this is the stuff I'm looking for. I've been following you for more than a year! 10/10 👍
I love how this started off like a documentary and ended like a good old BPS Space video with Joe doing something goofy, Can we have more of this is awesome :-)
the shots at 6:33 and 7:01 of it trying to correct itself and falling sideways are amazing, reminds me of shots of sn10 falling
"Launching rockets in the Mojave makes you wish for a nuclear winter."
Man, it's beautiful out there. And so many folks working on their passions that there is a dedicated site to do so. I didn't know such a place existed. Very cool! I really enjoyed the video, Joe. Thanks!
Holly Flight Recorder! 9:30 this is the bestestest tie a beardless guy can wear! Congrats on the flight+analysis, can't wait for the next espisode.
These new videos are something else man. You are incredible! One of my favorite creators out there man
Great work Joe, looking forward to the next launch 🚀
That sugar motor that blew up was a P-5,000 KNSB motor . 8" Dia.
I really appreciate the use of Subnautica music with your video. Love it! Would the rocket perform better if you have moving flaps on the back of the fins vs having the whole fin actuating?
Incredible! GL on flight 2!
Your grit, curiosity and ingenuity continue to amaze me Joe.
I'm getting strong subnautica vibes from the intro music. This slaps, amazing job, fits perfectly.
You have a very interesting problem here with the PIDS. You will either need to write an algorithm to adjust the PIDS over the flight during powered lift or when you are flying at low speed you will have no issue as illustrated then when the speed picks up and the controls become super effective your algorithm will overcorrect and it will freak it out. I would say redesigning the fins to move the actuation point all the way to the back and the pivot to the very nose of the fin. Gets the best Mechanical Advantage at high speed and provides better servo precision. Then either go for full-on speed for the tune only or sacrifice high-speed control unless you can switch the rates between the two. Then the rocket looks like it should be great!
This is a next-level project. Well done!
Amazing video Joe!! Cant wait to see the next flight of Fineas!! Loved the new concept of aerodynamic guidance and also loved the new way of vlog type coverage!
I think having the fins mounted to the servo is a weakness. Have a passive pivot point at the leading edge, but drive them laterally from as close to the trailing edge as possible for better leverage and stability. Yes, I mean having the linkage exposed.
Great video, thanks.
I don’t know how you do it but that stabilized tracking footage is CLEAN. Sooooo satisfying to watch
The subtle whine like a large tanker falling over in silence as it fell was so weird but amazing. 6:48
I love your content and always hope the best for you guys!
I'm out in Ridgecrest CA and it's just amazing that all this cool stuff is happening right next door to me!
Oh, buddy. That was a well made video and I hope you're not discouraged by the mechanical failure of the fins. Great progress was made here.
The decent was surreal. It was like a movie. Great job man.
That point about heat making the joints fail reminded me of Challenger's failed O-rings in the cold. Great video bro!
This channel sparks joy, thanks Joe
FAR is such a great place for experimental rocketry. Those guys out there are always great.
If you're ever doing anything with canards, the solid rocket team at San Diego State University has flown and the liquid team is planning to fly a rocket with forward control surfaces.
Amazing video! A few months ago, I thought about creating a fin controlled model rocket, but didn't see too much content on such a goal being achieved. I gave up on that project before I even started it. Now, with this video recently being released, I plan on pursuing this project again and learning as you go along! Can't wait to see the progress that is made along the way!
Awesome job !! And great edit !!!! Fix the issues and back to the air !!!
When the remove before flight tie came out I lost it. Great video and good luck on the next fin control flight.
I was see on the Advanced Model Rocket site that sugar motor explosion , and was not expecting you was next to it , amazing , jut be safe. Wery cool that your rocket survived that blast.
Glad to see another pilgrimage to FAR!
The real question after the failure is actually what parts resolidified after cooling. The launch video does show the failure almost at maximum altitude, the fins ( what little action/reaction there was ) looked good until melt slipage.
Option 7) Replace all linkage/parts with milled metals/carbonfiber and overkill the design, then fly again with the same flight program.
Congratulations Joe - as a test engineer I love every bit of this video :)
- well, apart from the bit where you ask vulnerable people to pay to become an intern, that smacks more of that other guy you don’t want to be 😂
But seriously, your camera tracking rocks, you have telemetry and live flight cam, parachute is fine and you survived the attack of the Sugarmonster! Onwards and, of course, upwards!
This is why you should support BPS on patreon
Enjoyed it tremendously, thanks
Amazing Work cant wait to see the future of this project!
Dude, I love in Mojave I saw the video of you driving in on the south side, love it. Haven't watched video yet, live your channel.
First idea out of my head remembering V-2's... don't move the whole fin. Try hard mount main fin with servo driven tail flaps. Also check directionality of motion with the directionality of the servo rod movement. Pull, not push. Pushing the rod will bend fighting aerodynamic forces. If it needs to operate in both planes of motion use dual rods. Use metal geared servos against such high aerodynamic forces. Also suggest hinge be multi-sectioned (Like piano hinge) with 50 percent of total hinge width pins. (Note: during fin construction, bend pin ends over on both ends into slots top and bottom of flap, glue in place.) Leave space for vibration of flap. Even though you think the fin will be solid to the fuselage, vibration will close the flap gap and the flap will rub on the tube. I missed the build video for the rocket. Building a chassis for the servos to sit in that is much more stable than just mounting to a bulkhead. Next I'd limit the movement to 11.75 degrees in each direction. At the Max-Q speeds your rocket is flying, you don't need much deflection for roll control.
JoeyB -legend! Love the sponsor segment at the end also!
Great video, that tie is a must buy
you are a legend!!!!!
It seems that the big sugar motor threw us a very nice party ...!!! Nice work.
Great first flight!! Double post the fin connection to the servo shaft and it won’t slip on you. Can’t wait for next flight!! Cheers!
nice uncontrolled disassembly Joe. Well done on the first flight. Hoping you got all the info.
im kinda new to this sort of thing, but i would recommend 3d printing a tray for the servos that you could epoxy into the fuselage of the rocket, but overall awesome concept and I hope to see more.
This waa genuinely awesome, congrats on a successful flight and recovery.
That Subnautica music at the beginning of the vid hits hard! 👌😩 Great Job!
"I don't think it worked, but that was great!" I agree completely;-) Very cool!
Holy crap! I've been out in the Mojave doing geophysical survey work for the past month, and am about to head out tomorrow for another three weeks in the desert. Are you guys planning on more tests in that time frame because I'd love to be able to spectate live if you are.
Also, my team were all wondering what those explosions were, now I can't wait to tell them what was going on. :)
Hey, Joe. First off, thank you for having the stones to post not just your many successes, but your failures as well. Not everyone has the ability to do that and you deserve thanks for doing so. Ok, secondly…. On mounting your fins. How about mounting the fin to a very small flat piece of aluminum that exactly matches the portion of the fin closest to the body of the rocket? Then you could weld a little shaft onto the plate and pass it thru a bearing or some type of seal/bushing that could keep it in the correct orientation and not allow it to wobble around once the air pressure against it increases during the launch event. I would also consider mounting the fins to the plates by screwing them from the shaft side and use some kickass epoxy or other adhesive of your choice. Having the metal control shafts would let you connect them to your servo horns (which it sounds like you are going to be replacing with aluminum for the next flight!) and eliminate any plastic or other parts that could potentially pose a risk of failure in high temp situations. Just think if you were to try and fly that thing in July or August down there in So Cal… it may have just melted right there on the rail! This is almost December so there are not many better weather patterns being offered by Mother Nature than what you were given. I learned my lesson with non metal servo horns when I was racing my 3D printed catamaran. My steering servo horn stripped the little teeth around the output shaft of the servo (who puts a metal geared high torque servo together using a plastic servo horn? Um, ahem, err, ok besides me I mean?) during a high speed run which did not end well when it failed suddenly and very completely…. 70mph into a stone wall at the edge of the lake. Wall vs 3D Boat. Wall 1, Boat nil.
It seems to me a control surface on the back of a fixed fin would be a bit more robust solution and have a much less wild failure mode. But I've only flown subsonic.
Interesting idea!
The fin deflection should in my opinion be limited to something like maybe 5° and the pivot could maybe be altered to 2 points one being the aft hinge point and a ring conector which is connected to all the fins near the leading edge one servo or gear would turn the ring connector. The ring would be centered by 3 or more small cartrage berrings to keep friction minimized.
These are my 2 cents, keep them or toss them that is your choice.
CAR cert 3, NAR cert 2
DE VE9GIS
The work you do is so inspiring!
keep it up
Thank you for uploading
This is my new favorite video! It's even better than Thoomp Flight 1 (which now is my second favorite video)
Lets goo. SO EPIC. Fineas be flying real high. Imma watch this video 3 times, cya.
"When it fails, it fails straight"
Same.
Good rocket, good flight, good video! One idea is that if you're doing more flights out in the hot desert, do a radiant heat test to ensure that this doesn't happen again and that everything else can withstand the desert sun
Which is to say, stand the rocket up, stick a temperature sensor in it, get some cheap heat lamps, point them at the rocket, get it nice and hot, and see if anything fails or melts or gets soft that shouldn't
I’m digging the subnautica soundtrack!
You are my idola. Excellent.
Really fascinating failure analysis! (Not a failure! Progress!)
Failure? No, more data!
Congrats! That was great!
I am super excited to be joining the BPS Internship this December. My uniform is on the way!
I was waiting for this one!!!
"May the skies be blue, and the winds be low" Amazing
Its definitely one of the cooler ones he's done
i find it funny that my immediate mental solution to the plastic bits softening was to have a reflective foil blanket over that part of the rocket that would fall away at launch. your solution is much, much more practical and actually would work.
Congratulations Joe
Reduce aerodynamic forces on servos and links by using control surfaces on fins instead of using "flying" fins. Also, why such aerodynamically terrible fins instead of 3D printed airfoils?
Doesn’t this present issues in transonic and supersonic regimes because the shock wave is pushed behind the control surface? It’s why the bell x-1 and other moved to stabilator vs elevators. Just spit balling here
My thoughts as well.
Perhaps don't run before you can walk - just use fixed fins, control surfaces on those fins and move said control surfaces using well-known servo/rod/horn setups taken from R/C aircraft. Sure you're going to struggle once you hit transonic speeds, but this thing is doing about half that at best.
The control pin idea mentioned elsewhere in the comments also sounds like a good way to go.
Transonic behavior is irrelevant with that rocket and motor size.
I agree with this and more (!). I've been thinking, why do they even need to move more that 5 degrees or so - more than that and it's too easy to make it do what happened, make the rocket turn 90 degrees to the direction of travel. Is the eventual idea to go supersonic on this design? I recall Chuck Yeager being surprised at how the controls were operating around Mach 1 and how it almost surely contributed to previous test pilots' crashes.
I'm "presuming" a lot here, that the fins are programmatically kept straight until after the rocket has left the launch tower, and so many other things I just now forgot. We all want Joe to succeed, and I'm hoping our comments are helpful and welcomed.
The transonic issue can be eliminated when he does scale up by articulating the outboard portion of the fin rather than the trailing edge, or using separate control fins like many missiles do, usually on the nose which leaves the rear volume for propellant and all the servos and controller in the nose.
I wonder if that’s the same team that just broke the record a few days ago!!
Great video.
Great... Love your work
I know this is late, but what about a synchronizer ring to position the fins? This is a mechanism used by variable vane turbochargers. You could position the ring towards the bottom of the rocket, allowing a forward hinge point, but drive it with something like a stepper motor from further up.
This has got to be the coolest channel I subscribe to. Any channel that can genuinely make me excited by saying "and now it's time to review the data" is definitely doing something right. I'm so excited to watch you find and overcome all the challenges in fin control. So cool.
One question: Even though the fins failed, can you tell if the control system was working by comparing the roll-rate measurements with the control system outputs? I.e. would it have worked if the fin joints has not failed?
For your fin stabilization, would you consider a fin layout similar to an AIM-54 or AGM-65 where the large fixed forward fins do the majority of the neutral stability and the guidance fins are there for fine control?
Another option would be to model the "Rollerons" that are found of the AIM-9 family of missiles. This is a passive control system that uses air speed to turn gyroscopes that are built in to control surfaces.
My suggestions would be to have four fins working the pitch and yaw, as those two axis will require a considerable amount more control input than the roll axis.
For the roll axis, I would limit the controls to be less than one third of the deflection the pitch and yaw receive, as well as maybe limiting the controls to two fins.
Have you thought of using a small barrel that rotates along the fuselage and to which all the fins would be attached? This and a fixed pivot on another part of the rocket would give the rocket rotational stability and prevent the possibility of failure as only one servo would be needed.
really freaking cool hobby you have here man, would be awesome to see you launch one of these and talk to you after about it. Rarely do you get to see someone with this much drive, talent and intellect create amazing things step by step but let alone in person. Looking forward to purchasing your flight computer and taking my small rocket hobby to the next level!
That sus sound effect tho, caught me off guard, blasting in laughter.
That was great!!! CONGRATULATIONS!!!!!!!!!!
SUBNAUTICA MUSICCCC letsgooo also im a model aviation guy so I prefer more controlled aviation, but rocketry is nuts! Keep up the cool stuff
launch
flight
descent
landing
more data
good job Joe, things are coming together more and more as you go along
I love your tie!
VERY EPIC, CONGRATS JOEY B
Maybe you can consider putting the fines upper on the rocket? I mean if you locate the servos and the fins right beneath the circuit boards, it might not get all that heat and still do the work.
“Never let your gas tank below half empty” half empty kinda guy I see.
Knew I recognized subnautica music! Love when I find people that enjoy that game as much as I do!
Totally agree on Subnautica!! The soundtrack is part of my near daily routine
Love the tie!
I love the tie!
Isn't that the Subnautica music in the background?