Two Stager Gone Wrong

rfjustin

Well-Known Member
Joined
Jan 21, 2009
Messages
4,151
Reaction score
4,159
Location
Franklin, WI
And that's why timers are no longer allowed by Tripoli to light a sustainer motor and why all two stage flights at Midwest Power have to be approved by the BOD (unless your name is Fred T.). :)
 

samb

Lifetime Member
Joined
Jan 22, 2009
Messages
4,512
Reaction score
950
Location
Plano, TX
Hmm...
Trending News ?!? Nine hours ago ?!?

Shame on you Weather Channel. Not enough bad weather video today ?
 

djs

Well-Known Member
Joined
Jul 27, 2014
Messages
3,382
Reaction score
264
(unless your name is Fred T.). :)

For those who haven't seen the videos of Fred's 4 stager, it's way awesome

[video=youtube;sIGzvkHYQfU]https://www.youtube.com/watch?v=sIGzvkHYQfU[/video]
 

ksaves2

Well-Known Member
TRF Supporter
Joined
Nov 25, 2009
Messages
6,562
Reaction score
690
Location
Central Illinois
It's an old video, happened a few years ago. There were a few threads about it.

Yup,

I was there and it was hairy to witness live. Was posted the flier was certain it would work and was aghast when it didn't. That's why the staging rules have been changed.

I was a witness at a Metamora launch where a tail heavy single stage rocket went up of a 54 mm research load. It looped twice, smacked the ground, flipped over a couple of times and took off at a 25 degree angle fortunately away from us. There were few attending this small launch. Incidentally, the deployment system worked and the rocket was recovered sans fins. All three snapped off leaving stubs. That was a CG issue if there ever was and a lesson that hairy flights can occur with single stage stuff too. Kurt
 

Sooner Boomer

Well-Known Member
Joined
Mar 21, 2011
Messages
4,984
Reaction score
3,094
You don't need staging or EX motors for excitement. One little bitty mid-air chuff and everybody hides behind (or under) cars. Next time I'm just going to stand there and DARE it to hit me! (besides, I don't move very fast now...).
 

jd2cylman

Still not Carl... ;-)
TRF Supporter
Joined
Jun 16, 2011
Messages
5,969
Reaction score
1,938
You don't need staging or EX motors for excitement. One little bitty mid-air chuff and everybody hides behind (or under) cars. Next time I'm just going to stand there and DARE it to hit me! (besides, I don't move very fast now...).

Been there, done that. I don't wanna do it again. 17 stitches and almost $2000.00 hospital emergency room bill. Luckily, my insurance covered 80%. Missed two weeks work, too.
Oh, and I have a nice permanent < imprinted on my shin...
 

Andrew_ASC

UTC SEDS 2017 3rd/ SEDS 2018 1st
Joined
Sep 22, 2017
Messages
3,883
Reaction score
535
You don't need staging or EX motors for excitement. One little bitty mid-air chuff and everybody hides behind (or under) cars. Next time I'm just going to stand there and DARE it to hit me! (besides, I don't move very fast now...).
The Air Raid Siren and people yelling HEADS UP. Then there's always this stone cold savage who stands still scanning like a professional eagle eye hawk and yells I SEE IT.... Flew and designed two multistages USRC SEDS one placed third last year. Interstage implosion got exciting at M1.5. The L-3 ballistic still tops it all. People went sprinting. Damn thing left a crater with fin marks, lol. It would've killed a car I reckon. Except for the cold savage spotter, who actually found it incoming before the others.
 

rharshberger

Well-Known Member
Joined
Oct 13, 2014
Messages
11,960
Reaction score
3,787
Location
Pasco, WA
Is this documented somewhere ? I know several people in my club who purchased timers for their Nike Apache kits.


Sent from my iPhone using Rocketry Forum
I know the Missleworks PET2+ has accelerometers and stuff to use set points that if certain prameters are not met the second stage ignition will not occur. The prohibition may be straight timers that have no safety inhibitors, clarification would be good, with specfic timers listed that can be used.
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
8,447
Reaction score
6,837
Location
Butte, Montana
Is this documented somewhere ? I know several people in my club who purchased timers for their Nike Apache kits.


Sent from my iPhone using Rocketry Forum

I’d like to know also.
The only prohibited means of controlling the ignition of motors is this, from the Tripoli HPR Safety Code:
A-5 A rocket motor shall not be ignited by using:
a. A switch that uses mercury.
b. “Pressure roller” switches


I would be in favor of requiring some kind of inhibition against off-axis (tilted) staging, but we haven’t outlawed timers.

Steve Shannon
 
Last edited:

samb

Lifetime Member
Joined
Jan 22, 2009
Messages
4,512
Reaction score
950
Location
Plano, TX
Is this documented somewhere ? I know several people in my club who purchased timers for their Nike Apache kits.


Sent from my iPhone using Rocketry Forum

The Tripoli Range Safety Guidelines document has this item on page 20 as relevant for multi-stage rockets:

- If required, make sure that the staging electronics have a feature to inhibit staging
events if the rockets flight profile does not follow expected behavior.


https://www.tripoli.org/Portals/1/Documents/Safety Code/Range Safety Guidelines v1.3.pdf


Maybe not a ban but I'll bet the RSO's at Midwest Power wont let another stager go with only a timer after that happened in 2014.
 

rfjustin

Well-Known Member
Joined
Jan 21, 2009
Messages
4,151
Reaction score
4,159
Location
Franklin, WI
Samb posted the link to the safety code (which is where my statement came from about timers). Simply put, timers should be used for separation charges, not lighting motors.

I'm working on a 4.5" two stage right now where a timer is being used to separate stages, but radio controlled ignition of sustainer motor.
 

Titan II

Well-Known Member
Joined
Aug 23, 2013
Messages
1,464
Reaction score
576
Samb posted the link to the safety code (which is where my statement came from about timers). Simply put, timers should be used for separation charges, not lighting motors.

I'm working on a 4.5" two stage right now where a timer is being used to separate stages, but radio controlled ignition of sustainer motor.

He did not post a link to a safety code. It was a link to a guideline which specifies:

"The following Guidelines are not meant to add to, subtract from, or supersede any of the Tripoli Safety Codes."

No code prohibits using a timer.
 

rfjustin

Well-Known Member
Joined
Jan 21, 2009
Messages
4,151
Reaction score
4,159
Location
Franklin, WI
He did not post a link to a safety code. It was a link to a guideline which specifies:

"The following Guidelines are not meant to add to, subtract from, or supersede any of the Tripoli Safety Codes."

No code prohibits using a timer.

Sheesh... pardon me! Range Safety Guidelines, not Safety Code...
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
8,447
Reaction score
6,837
Location
Butte, Montana
Samb posted the link to the safety code (which is where my statement came from about timers). Simply put, timers should be used for separation charges, not lighting motors.

I'm working on a 4.5" two stage right now where a timer is being used to separate stages, but radio controlled ignition of sustainer motor.

The Tripoli Range Safety Guidelines are an excellent resource, but a bit of clarification might help.
First, that is not the Safety Code. They are a collection of best practices to help our members as they conduct range operations. That certainly doesn’t mean they should ever be ignored, but it’s important to understand what they are and the context they’re to be used in.
Second, that quote is from the section that provides guidance on how rockets are to be inspected. Note the dependent clause in the quote: “If required,”. What that means is IF a particular launch site HAS such a requirement the flight safety inspection process should check for it. It does not imply that such a requirement exists Tripoli wide. Although I’d like to see some kind of requirement, it hasn’t been decided upon yet. There are several ways to approach it, but for now simple timers are allowed for staging unless locally prohibited.
I would invite comments on the Tripoli forum for how to write such a requirement, but I won’t promise it’ll be enacted soon. I’ll start a thread there.



Steve Shannon
 

mikec

Well-Known Member
Joined
May 9, 2009
Messages
2,799
Reaction score
591
No staging electronics, no matter how sophisticated, should be a substitute for basis stability analysis. The rocket in this video just wasn't stable off the rail.
 

ksaves2

Well-Known Member
TRF Supporter
Joined
Nov 25, 2009
Messages
6,562
Reaction score
690
Location
Central Illinois
Ummmm, Any group can make more stringent requirements than any national organization requires. It behooves one to be aware of what they are. It's a waste of time whining about it so find out what is required and try to comply. If you can't, you
can't fly the project. That said, if one has a small 2 stager that flies on a timer and has had successful flights, send the sponsoring group the video(s), the flier can swear on a stack of bibles they will fly the same motor combination and the sponsoring group can say "Yay" or "Nay". Be aware they can still say no but if it looks good on a video and they feel the flier is honest, they might give an okay.

The major issue is having enough power to get off the pad safely with the first stage and fly the first stage in a stable manner.
What's appropriate for a launch attended by 6 fliers is one thing but at a national meet, it's a whole 'nother ball of wax. Kurt Savegnago
 
Top