10km Test Bed (updated)

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LitmusAero

Well-Known Member
Joined
Apr 8, 2022
Messages
57
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Location
Hebron, KY
Hey everyone!
I'm working on some flight hardware. Specifically, i'm working on a custom Flight Computer and some separation gear (I'll post about those when I get some flight time). Anyways, rapidly iterating prototypes involves a lot of testing, and for that I need a reliable test bed that can do 1km flights all the way to 10km+ Flights and safely, reliably and quickly recover and reuse. That being said, if you're looking for a crazy, out there rocket design, this isn't it. This was designed purely to test hardware, most of the time 1 of 1 models, so any unnecessary risks were avoided, such as multiple deployment events or separation events. This also means the recovery system has to be extremely reliable and redundant.

Introducing Fusion:
Screenshot 2022-06-10 005240.pngOverview:
Fusion is a 98mm Minimum Diameter Rocket. It stands just over 6.4 feet (1.9 Meters), and can reach over 10km. It is a full fiberglass airframe construction, with G10 Sheet Fins.


Motor/Retention:
Fusion can fly on any 98mm Motor 1010mm in length or less that can adapt to a 1/4-20 thread (Aeropack Minimum Diameter Retainer). This gives us a healthy motor range of K-N.
As stated before, the motor will be held in place by a 98mm Minimum Diameter from Aeropack, I chose to omit the included eye bolt as this rocket won't utilize dual-deployment.
Fusion will mostly fly on commercial motors for reliability and repeatability reasons, but it was designed to accept 98mm single use EMK's for future projects.

Airframe/Nose Cone/Fins:

Fusion is based on a 4" G12 Filament Wound Fiberglass Tube, 0.12" in thickness. The Airframe is a solid piece (no fin can or switch bands), optimized for a peak thrust of 15kn. It will be sanded finely, painted over and finally enameled and polished. The nose cone is a 4.5-1 VK with a stepped aluminum tip from Wildman. The fins are of my own design, built on G-10 stock, nothing special, just built to be low drag and sturdy. The vehicle can reach up to mach 2.4, so it took a lot of redesigns to get the fins semi-optimized. Here is the data from open rocket:
Screenshot 2022-06-10 000050.pngScreenshot 2022-06-10 000618.png
Screenshot 2022-06-10 001258.png

Electronics/E-Bay:
The E-Bay is one of the most important parts of this build, as it needs to protect things I really don't want broken. It's a fully custom bay, using a 9 inch fiberglass coupler, two 1/4 inch threaded rods, a 3 1/2 inch by 7 inch balsa plate, and two aluminum bulkheads with rubber gaskets. The Main Flight Computer will be a Raven Altimeter, along with a Featherweight for tracking. The bay is designed to carry multiple Boards for testing as well, so the Raven may act as a redundant computer in cases where pyro events need to be tested on a custom board. In any case, there will always be a redundant computer with separate redundant charges.

Recovery:
The main chute is a 36" Iris Ultra HP. It is deployed with a BP charge, and sits in between the nose cone coupler bulkhead and main airframe. Recovering the payload in-tact is much more important than the booster, so in case of main deployment failure, a "small" bit of code on the flight computer can detect a too rapid or erratic decent, and fire a charge in between the aft bulkhead and motor retainer, shredding the airframe at that section and separating the payload from the nose cone. The reduced weight and jolt of this separation will (in theory) help to untangle the chute or allow it to catch some air. Even if it doesn't fully open, the newly reduced weight will allow it touch down at a safe-ish speed. The booster has a 24 inch plastic chute attached to the retainer wrapped in a nomex blanket, this will unfurl and keep the booster from going ballistic.
Parachute Specs:
Screenshot 2022-06-10 004740.png

Future Upgrade Ideas:
  • Line Cutter/Reserve Parachute for Payload Bay
  • Piston Deployment
Random Sims:

Cesaroni N2501 (Selected for high Altitude Flights)
Screenshot 2022-06-10 010517.png
Cesaroni N5600 (selected for high speed/mach flights)
screenshot-2022-06-10-010920-png.522431

Anyways, that's all I got. Let me know if you have any ideas for improving the design.
-Sam
 

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Nice project.

With the fins behind the aft airframe you might want to consider a larger chute than you might normally use. Maybe. YMMV.

Fusion can fly on any 98mm Motor 1010mm in length or less that can adapt to a 1/4-20 thread (Aeropack Minimum Diameter Retainer). This gives us a healthy motor range of K-N.
You can hang longer motors out the back if stability is sufficient. ;)
 
Nice project.

With the fins behind the aft airframe you might want to consider a larger chute than you might normally use. Maybe. YMMV.


You can hang longer motors out the back if stability is sufficient. ;)
Sims giving an average of 9 m/s ground hit velocity, should be ok, but maybe a 48” wouldn’t hurt.

Guess an O8000 would be pretty fun 😁
 
How much experience do you have with high power rockets? The 3mm G10 fins seem kind of thin for a rocket that size intended to go as fast as your simulations indicate.

The recovery system also seems undersized. The 36" parachute might be appropriate for a site like Black Rock, but the 24" parachute will be totally inadequate. A plastic parachute will just shred of it's deployed while the rocket is moving with any appreciable speed.
 
How much experience do you have with high power rockets? The 3mm G10 fins seem kind of thin for a rocket that size intended to go as fast as your simulations indicate.

The recovery system also seems undersized. The 36" parachute might be appropriate for a site like Black Rock, but the 24" parachute will be totally inadequate. A plastic parachute will just shred of it's deployed while the rocket is moving with any appreciable speed.
Working on a new updated thread, that was the baseline design. Since then I’ve upgraded to a full metal fin can from Maxq.

Very true on the plastic chute, it’s for emergency only, and will only hold the weight of the empty booster (5kg), but we’ve also upgraded this to Nylon.
 
Just because you are launching at Black Rock doesn’t allow you to burn stuff in with an inadequate parachute.
A 24” chute plastic chute is too small and is going to fail. Will not pass RSO.
It’s now nylon and Kevlar, and also never to be deployed unless the main chute is descending way way faster.

Buddy was an RSO for my NAR site I went to, said he would have approved it for flight given it’s for backup only, and I had sims to prove it would most likely be deployed within safe speeds. Maybe that’s why he USED to be one lol. (He moved, that’s a joke my humor is trash sorry haha)

I am still considering a larger chute, but it would mean expanding my already built drogue bay, not crazy difficult but also not desirable.

For now, the backup chute will keep the descent under 20m/s which is allowable for reserve chutes in an extremely isolated location like Blackrock.
-Sam
 
For now, the backup chute will keep the descent under 20m/s which is allowable for reserve chutes in an extremely isolated location like Blackrock.
Where did you come up with this?

At a launch no matter where it is it is never "extremely isolated." There is hundreds of people and vehicles.
 
Where did you come up with this?

At a launch no matter where it is it is never "extremely isolated." There is hundreds of people and vehicles.
Not launching at a registered launch site, private farm my family owns in the middle of nowhere in Ohio.
Only people there will be a few family/friends inside the house Roughly half a kilometer from the pad.

The 20m/s was my limit, even this speed could defienetly get dangerous, but given my remoteness and estimated landing points, 20m/s limit is more to keep the rocket from breaking something upon landing.
 
Not launching at a registered launch site, private farm my family owns in the middle of nowhere in Ohio.
Only people there will be a few family/friends inside the house Roughly half a kilometer from the pad.

The 20m/s was my limit, even this speed could defienetly get dangerous, but given my remoteness and estimated landing points, 20m/s limit is more to keep the rocket from breaking something upon landing.
Edit: the reason I’m not launching at a registered site is my use of a metal fin can. Not allowable per NAR so no go at a public launch.
 
Aeropac retainers for a 98mm motor are not 1/4 20. Off the top of my head I want to say 5/16 14???


Edit Here it is.

M98: for 98mm airframe and motor mount tubing
Motor mounting stud on bottom of retainer is 3/8-16.
Accessory mounting hole on top of retainer is threaded 5/16-18.
M98E includes a 5/16 inch machine eye-bolt.
 
Aeropac retainers for a 98mm motor are not 1/4 20. Off the top of my head I want to say 5/16 14???
Oh right, I was thinking about the forward bolt section of the Aeropac that can hold the eye bolt, that one is 1/4-20.

Glad you knew what I meant lol
 
Aeropac retainers for a 98mm motor are not 1/4 20. Off the top of my head I want to say 5/16 14???


Edit Here it is.

M98: for 98mm airframe and motor mount tubing
Motor mounting stud on bottom of retainer is 3/8-16.
Accessory mounting hole on top of retainer is threaded 5/16-18.
M98E includes a 5/16 inch machine eye-bolt.
Where did you find that? My data is probably incorrect but I have the top accessory bolt as a 1/4-20.
 
The premise of having a reserve parachute just feels really weird to me. I'd focus on ensuring redundancy and reliable operation of the main parachute system.

Moving to the aluminum fin can does seem like a sensible choice, but this project seems far too advanced for someone with as far as I can tell no experience with high power rockets.

Why do you even need to fly to 10km to test electronics? If you just want to do basic flight tests, you should only need a mid power rocket to verify functionality and performance.
 
Edit: the reason I’m not launching at a registered site is my use of a metal fin can. Not allowable per NAR so no go at a public launch.
A metal fin can like the Max Q one you chose would be fine at a Tripoli launch. If you want to do this legally, you'll almost certainly need to fly at an official launch. If you do this, you'll also need a level 3 certification.
 
A metal fin can like the Max Q one you chose would be fine at a Tripoli launch. If you want to do this legally, you'll almost certainly need to fly at an official launch. If you do this, you'll also need a level 3 certification.
Not a Tripoli member, would my Certs carry over to it? That’s definitely helpful if I can.
I’m doing this through my LLC, so it’s a little easier going through the FAA Myself, but still not ideal.

I agree that it’s not a perfect solution using the Reserve chute, but I have minimal experience with tender decenders so I don’t feel comfortable flying with one on such a high altitude rocket. Perhaps I’ll do a smaller build and get some experience using them, as I’d certainly not like to blow out my body tube every time my main tangles.

To answer your previous question, Barometric sensors can sometimes be more inaccurate the further up you go, so I need a way to compare that to a Sensor that is pre calibrated. I also just wanted an excuse to spend more money on rockets 🤷‍♂️

-Sam
 
Hey everyone!
I'm working on some flight hardware. Specifically, i'm working on a custom Flight Computer and some separation gear (I'll post about those when I get some flight time). Anyways, rapidly iterating prototypes involves a lot of testing, and for that I need a reliable test bed that can do 1km flights all the way to 10km+ Flights and safely, reliably and quickly recover and reuse. That being said, if you're looking for a crazy, out there rocket design, this isn't it. This was designed purely to test hardware, most of the time 1 of 1 models, so any unnecessary risks were avoided, such as multiple deployment events or separation events. This also means the recovery system has to be extremely reliable and redundant.

Introducing Fusion:
View attachment 522428Overview:
Fusion is a 98mm Minimum Diameter Rocket. It stands just over 6.4 feet (1.9 Meters), and can reach over 10km. It is a full fiberglass airframe construction, with G10 Sheet Fins.


Motor/Retention:
Fusion can fly on any 98mm Motor 1010mm in length or less that can adapt to a 1/4-20 thread (Aeropack Minimum Diameter Retainer). This gives us a healthy motor range of K-N.
As stated before, the motor will be held in place by a 98mm Minimum Diameter from Aeropack, I chose to omit the included eye bolt as this rocket won't utilize dual-deployment.
Fusion will mostly fly on commercial motors for reliability and repeatability reasons, but it was designed to accept 98mm single use EMK's for future projects.

Airframe/Nose Cone/Fins:

Fusion is based on a 4" G12 Filament Wound Fiberglass Tube, 0.12" in thickness. The Airframe is a solid piece (no fin can or switch bands), optimized for a peak thrust of 15kn. It will be sanded finely, painted over and finally enameled and polished. The nose cone is a 4.5-1 VK with a stepped aluminum tip from Wildman. The fins are of my own design, built on G-10 stock, nothing special, just built to be low drag and sturdy. The vehicle can reach up to mach 2.4, so it took a lot of redesigns to get the fins semi-optimized. Here is the data from open rocket:
View attachment 522418View attachment 522419
View attachment 522420

Electronics/E-Bay:
The E-Bay is one of the most important parts of this build, as it needs to protect things I really don't want broken. It's a fully custom bay, using a 9 inch fiberglass coupler, two 1/4 inch threaded rods, a 3 1/2 inch by 7 inch balsa plate, and two aluminum bulkheads with rubber gaskets. The Main Flight Computer will be a Raven Altimeter, along with a Featherweight for tracking. The bay is designed to carry multiple Boards for testing as well, so the Raven may act as a redundant computer in cases where pyro events need to be tested on a custom board. In any case, there will always be a redundant computer with separate redundant charges.

Recovery:
The main chute is a 36" Iris Ultra HP. It is deployed with a BP charge, and sits in between the nose cone coupler bulkhead and main airframe. Recovering the payload in-tact is much more important than the booster, so in case of main deployment failure, a "small" bit of code on the flight computer can detect a too rapid or erratic decent, and fire a charge in between the aft bulkhead and motor retainer, shredding the airframe at that section and separating the payload from the nose cone. The reduced weight and jolt of this separation will (in theory) help to untangle the chute or allow it to catch some air. Even if it doesn't fully open, the newly reduced weight will allow it touch down at a safe-ish speed. The booster has a 24 inch plastic chute attached to the retainer wrapped in a nomex blanket, this will unfurl and keep the booster from going ballistic.
Parachute Specs:
View attachment 522429

Future Upgrade Ideas:
  • Line Cutter/Reserve Parachute for Payload Bay
  • Piston Deployment
Random Sims:

Cesaroni N2501 (Selected for high Altitude Flights)
View attachment 522430
Cesaroni N5600 (selected for high speed/mach flights)
screenshot-2022-06-10-010920-png.522431

Anyways, that's all I got. Let me know if you have any ideas for improving the design.
-Sam
Hey everyone, just to mention, after talking with a few forum members, I’ve decided that going with the reserve parachute as stated would be unsafe and impractical , and will be redesigning the recovery system.
I’ll post an update when it’s done.

Thanks for everyone’s help!
-Sam
 
I wish you much success. I've flown on my own for over 50 years (low power only) and the worst I have experienced is a lawn dart from about 800'.
There isn't a club within reasonable distance of me or I probably would have advanced to level 2.
Too late in life to worry about it now. So go big while you can!
Enjoy the ability to fly on your own while you still can because the world is over populated and space is running out.
 
I wish you much success. I've flown on my own for over 50 years (low power only) and the worst I have experienced is a lawn dart from about 800'.
There isn't a club within reasonable distance of me or I probably would have advanced to level 2.
Too late in life to worry about it now. So go big while you can!
Enjoy the ability to fly on your own while you still can because the world is over populated and space is running out.
I appreciate it!
 
Hey everyone, just to mention, after talking with a few forum members, I’ve decided that going with the reserve parachute as stated would be unsafe and impractical , and will be redesigning the recovery system.
I’ll post an update when it’s done.
Glad to hear it.

Will you be including a tracker? A GPS tracker that sends information over a long range system while it's coming down? If you're going with that 36" (or bigger) parachute all the way down from 10 km, you're going to need it. You're in for some really long recovery walks drives. Also, be sure to put your name and contact information on the rocket.

This is somewhat mitigated by a Tender Descender or Jolly Logic Chute Release. I get that recovering the payloads is of very great importance; you should weigh the risk of a somewhat more complicated recovery system against the risk of losing the payload because it drifted miles away.
 
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