Orion Launch Abort System (LAS) - (picture heavy).

Discussions for scratch builders. For the enthusiast that builds from the ground up. Tell us what you've built and what projects you working on in the space race.

Moderator: Moderators

User avatar
Digit
Rocket Crew
Rocket Crew
Posts: 318
Joined: Sun Feb 21, 2016 1:23 pm
Location: Ipswich, QLD

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby Digit » Mon Aug 07, 2017 8:59 pm

How would I restrain a rocket for a static test without damaging it?
QRS:169
AMRS:108 (L1)

QRS Committee Member

User avatar
OverTheTop
It's only money...
It's only money...
Posts: 2359
Joined: Sat Jul 21, 2007 2:20 pm
Location: Melbourne, Australia

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby OverTheTop » Mon Aug 07, 2017 10:16 pm

If I didn't want to risk ruining my work I would make something up that looked like it. Maybe a bit of pine round, or something, with a hole drilled in to mount the motor. Or a scrap of airframe with a test motor roughly glued in place. Nothing fancy. Just a mockup.
TRA #13430
L3
"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

User avatar
Digit
Rocket Crew
Rocket Crew
Posts: 318
Joined: Sun Feb 21, 2016 1:23 pm
Location: Ipswich, QLD

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby Digit » Tue Aug 08, 2017 8:34 pm

Static test has been completed and I must say I am pretty happy with the results. I constructed a mock-up airframe utilising PVC tube and notched an SCR motor into it at the same angle as one of the motors from the flying model. For safety I mounted the motor vertically and canted the airframe, just in case something went wrong I'd fire the motor into the air instead of into a neighbor's house. The motor was fastened to a stake with a stainless steel zip tie, then several layers of tape and a second stainless zip tie over the top.

Video of test below.



From reviewing my test results and footage I am confident no structural damage will occur to the airframe and if cosmetic damage were to occur to the white finish it will most likely be during the tracking smoke phase where the bigger sparks are just bumbling out slowly, especially with forward momentum added.

After test before wiping airframe off:
Image

After wiping airframe off, seven larger pock marks from embers and a feint spray pattern:
Image

As this is not a rocket I intend to fly over and over again, I don't think that the test results warrant any type of added protection. I am quite happy to have those few small marks on there to prove it flew 8)

To be honest I am actually more worried about the orientation of the ejection charges looking at the size of them from one of my test footage angles:
Image

Would it be worth trying to protect the inside of the airframe, thoughts?

Thanks for the help everybody!
QRS:169
AMRS:108 (L1)

QRS Committee Member

User avatar
SpaceManMat
Astronaut
Astronaut
Posts: 1769
Joined: Mon Dec 15, 2008 9:56 pm
Location: Brisbane

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby SpaceManMat » Tue Aug 08, 2017 8:50 pm

Actually you probably want to avoid having 2 or more charges going off at the same time. You might want to cap the charge in with epoxy on 3 of them. I think 1 would be fine against the tube, they tend to want to take the easiest path which is out the end of tube.

Nice result with the experiment BTW.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 10,849 feet
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

User avatar
OverTheTop
It's only money...
It's only money...
Posts: 2359
Joined: Sat Jul 21, 2007 2:20 pm
Location: Melbourne, Australia

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby OverTheTop » Tue Aug 08, 2017 9:14 pm

You have thought the test setup through well. Good work Digit. Good result too!
TRA #13430
L3
"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

Kryten
Astronaut
Astronaut
Posts: 1948
Joined: Wed Oct 24, 2007 11:06 am
Location: Sydney

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby Kryten » Wed Aug 09, 2017 12:42 pm

SpaceManMat wrote:Actually you probably want to avoid having 2 or more charges going off at the same time. You might want to cap the charge in with epoxy on 3 of them.

Sealing the end of the motor sounds like a bad idea. The clay plug is designed to be a weak point; the clay nozzle - not so much.
If you wanted to plug them with epoxy you should remove the ejection charge first. This is contrary to the model rocket safety code.
You could buy plugged motors, but I don't think the ejection charges will have a major effect on the tube.
"Pub, ah yes. A meeting place where people attempt to achieve advanced states of mental incompetence by the repeated consumption of fermented vegetable drinks" (“Timeslides”)

RainierWolfcastle
Parachute Packer
Parachute Packer
Posts: 19
Joined: Wed Sep 02, 2015 11:29 am

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby RainierWolfcastle » Wed Aug 09, 2017 3:48 pm

Kryten wrote:
SpaceManMat wrote:Actually you probably want to avoid having 2 or more charges going off at the same time. You might want to cap the charge in with epoxy on 3 of them.

Sealing the end of the motor sounds like a bad idea. The clay plug is designed to be a weak point; the clay nozzle - not so much.
If you wanted to plug them with epoxy you should remove the ejection charge first. This is contrary to the model rocket safety code.
You could buy plugged motors, but I don't think the ejection charges will have a major effect on the tube.



Might be able to find C6-7's to swap for two of the motors to stagger the charges?
- Ben

 "If I have seen further, it is by standing on the shoulders of giants." - Sir Isaac Newton, 1675

User avatar
OverTheTop
It's only money...
It's only money...
Posts: 2359
Joined: Sat Jul 21, 2007 2:20 pm
Location: Melbourne, Australia

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby OverTheTop » Wed Aug 09, 2017 5:13 pm

Might be able to find C6-7's to swap for two of the motors to stagger the charges?


More clever thinking! Keep up the good work. :D
TRA #13430
L3
"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

User avatar
SpaceManMat
Astronaut
Astronaut
Posts: 1769
Joined: Mon Dec 15, 2008 9:56 pm
Location: Brisbane

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby SpaceManMat » Wed Aug 09, 2017 5:53 pm

RainierWolfcastle wrote:
Kryten wrote:
SpaceManMat wrote:Actually you probably want to avoid having 2 or more charges going off at the same time. You might want to cap the charge in with epoxy on 3 of them.

Sealing the end of the motor sounds like a bad idea. The clay plug is designed to be a weak point; the clay nozzle - not so much.
If you wanted to plug them with epoxy you should remove the ejection charge first. This is contrary to the model rocket safety code.
You could buy plugged motors, but I don't think the ejection charges will have a major effect on the tube.



Might be able to find C6-7's to swap for two of the motors to stagger the charges?


Actualy a C6-0 would be the way to go if you plugged the motor tube or motor. My local dealer suggested plunging B6-4 motors when I enquired about the availability of B6-0 for motors in a side pod. The charge normally has 2 ways to go - out the nozzle and out the forward end, if it cannot escape out the forward end it vents out the nozzle was his response.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 10,849 feet
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

User avatar
Digit
Rocket Crew
Rocket Crew
Posts: 318
Joined: Sun Feb 21, 2016 1:23 pm
Location: Ipswich, QLD

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby Digit » Wed Aug 09, 2017 5:54 pm

Some good ideas coming out now, keeping it simple! I was thinking of sourcing C6-0's and plugging them with epoxy as suggested. Seeing as my sim shows optimum delay as 4 seconds and I don't think it's actually going to fly as high with canted thrust I might even run 2 C6-3's and 2 C6-5's so I can easily buy the motors on the day and keep it SCR.
QRS:169
AMRS:108 (L1)

QRS Committee Member

User avatar
OverTheTop
It's only money...
It's only money...
Posts: 2359
Joined: Sat Jul 21, 2007 2:20 pm
Location: Melbourne, Australia

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby OverTheTop » Wed Aug 09, 2017 5:59 pm

If you want ideas, when plugging your motor you can use a fine drill and just drill the cardboard at the top end of the motor to allow some wire to be retained by the cardboard. Make a cross of wire across the top of the motor (maybe glue it in place and then cut the wire off level with the OD of the motor) and then fill the top of the motor with epoxy. I have heard of it being done that way before. It is more solid than just a plug of epoxy and it does not affect the strength of the motor casing where it matters.

Since you are drilling around the BP ejection charge, be careful, and wear PPE (especially safety glasses or face shield), or just don't do it.

Also remember the motor is technically modified if you do this.
Last edited by OverTheTop on Wed Aug 09, 2017 6:07 pm, edited 1 time in total.
TRA #13430
L3
"Everybody's simulation model is guilty until proven innocent" (Thomas H. Lawrence 1994)

User avatar
Digit
Rocket Crew
Rocket Crew
Posts: 318
Joined: Sun Feb 21, 2016 1:23 pm
Location: Ipswich, QLD

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby Digit » Wed Aug 09, 2017 6:07 pm

SpaceManMat wrote:if it cannot escape out the forward end it vents out the nozzle was his response.


This actually a controlled experiment I'd like to setup after MARS Attacks and document the results to share. I personally think old mate has given you a bum steer and the charge would blow the nozzle out completely or even worse fire the plug out like a bullet. Only one way to know though.
QRS:169
AMRS:108 (L1)

QRS Committee Member

User avatar
SpaceManMat
Astronaut
Astronaut
Posts: 1769
Joined: Mon Dec 15, 2008 9:56 pm
Location: Brisbane

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby SpaceManMat » Wed Aug 09, 2017 7:21 pm

Digit wrote:
SpaceManMat wrote:if it cannot escape out the forward end it vents out the nozzle was his response.


This actually a controlled experiment I'd like to setup after MARS Attacks and document the results to share. I personally think old mate has given you a bum steer and the charge would blow the nozzle out completely or even worse fire the plug out like a bullet. Only one way to know though.

Well he'll be there with you so will be an interesting outcome, document away. I've not even started the planned build so personally was not too concerned at this stage.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 10,849 feet
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

User avatar
Digit
Rocket Crew
Rocket Crew
Posts: 318
Joined: Sun Feb 21, 2016 1:23 pm
Location: Ipswich, QLD

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby Digit » Wed Aug 09, 2017 7:28 pm

SpaceManMat wrote:Well he'll be there with you


Haha, now I'm even more concerned about it blowing up :mrgreen:
QRS:169
AMRS:108 (L1)

QRS Committee Member

User avatar
crom
Rocket Crew
Rocket Crew
Posts: 301
Joined: Sun Dec 25, 2011 9:13 pm
Location: Brisbane
Contact:

Re: Orion Launch Abort System (LAS) - (picture heavy).

Postby crom » Sun Aug 20, 2017 6:16 pm

Not my best video.....

QRS #100 President
AMRS #20 L3

http://qldrocketry.com/


Return to “Scratch Built”

Who is online

Users browsing this forum: No registered users and 2 guests