Post your Raven FIPa files here

The Rocketry Forum

Help Support The Rocketry Forum:

Cpig

Active Member
Joined
Jun 19, 2012
Messages
27
Reaction score
0
Well, I dunno. I'm no expert. I started this thread because I wanted to learn a lot more about mining this data to get to the facts. Here's what I see in your file:

Your launch site is about 5,000 feet above sea level? (Colorado?)

Accell velocity data got to zero about 12.6 seconds

Baro says apogee was between 12.6 & 13.2 seconds - so it matches the accelerometer well
(if the vent holes were not right wouldn't it force accel & baro data to disagree?)

Apogee channel event went off at 13.7 seconds as you say, so ~1 second after both sensors sensed apogee

How was your Raven programmed for apogee trigger?

What ematch did you use for apogee? Powder type? Amount? Enclosure?

Here's a far out idea: Were you the one making the video? Maybe your position relative to the flight gave a bit of an illusion that it was on the way down when it was still more-or-less horizontal at apogee? Again, I dunno. But I have seen something like that. What do you think?
Yes, Colorado. I was using Quest Q2G2 ignitors and 1 gram of Goex FFFFG, Raven apo set to default increasing baro - also had 15sec delay on Cesaroni motor for ALT Apogee charge. Both charges fired but I believe they went simultaneously. I was not the one filming it, not sure who did but I found this video on the COSROCS webpage.

I looked at the video, and I think that a lot of the apparent lateness is from the optical illusion you get when the rocket is overhead and flying upward and away from you with a decent horizontal apogee speed, and it looks like it's descending. As it arcs over, the curvature of the flight even makes it look like it's speeding up when really its just that you're getting a more side-on view. 1/4" is a pretty huge vent hole, so I doubt that the internal pressure was lagging much. The accel-based apogee detection agreed with the baro data as well.
Adrian, you may be right. I only have three launches with this rocket, the first apogee went unobserved as it was on a CTI 6 grain J, and the last was on another CTI I which didn't give me the illusion. What really matters though, is that the Raven worked great and brought the rocket down successfully in all three cases.

I did not time the sound of the charge going off in the video, but he reported it lined up with the Raven data pretty good. The apogee (baro) was almost exactly 2100 feet. I looked at how long he spent within 50 feet of that just to get an arbitrary sense of how long it was going more horizontal than vertical. It got to ~2050 feet at about 11 seconds and fell back to 2050 feet at almost 15 seconds. So it spent a long time near apogee. Maybe this 'hang time' explains it?
Great observation cvanc. That seems to corroborate what Adrian said with his falling rock illusion theory.
 

Sailorbill

Well-Known Member
Joined
Jan 25, 2009
Messages
1,283
Reaction score
0
Here are four files, the first is my Ultimate Endeavour Phred on a CTI L1720 White Thunder, then Phred again from last weekends T.H.O.R. BOB launch on a CTI M3100 (See Picture), and the next two are from my grandsons 4" Endeavour not sure of the motors.
Both of Phreds flights had a recovery failure. The Drogue came out but the main did not. I am trying to get dual deploy out of one tube and not having much luck.
I have one more file but it is to large to post so I will need to figure out how to reduce it.

View attachment L1720WT8-18-12.Phred.pickrell.2.FIPa

View attachment M3100-10-21-12.Phred.FIPa

View attachment fip1091.Endeavour4.002.FIPa

View attachment fip1091.Endeavour4.001.FIPa

Phred-10-24-12-w.jpg
 
Last edited:

cvanc

Well-Known Member
Joined
Jul 24, 2012
Messages
1,303
Reaction score
27
Here are four files, the first is my Ultimate Endeavour Phred on a CTI L1720 White Thunder, then Phred again from last weekends T.H.O.R. BOB launch on a CTI M3100 (See Picture), and the next two are from my grandsons 4" Endeavour not sure of the motors.
Both of Phreds flights had a recovery failure. The Drogue came out but the main did not. I am trying to get dual deploy out of one tube and not having much luck.
I have one more file but it is to large to post so I will need to figure out how to reduce it.

Nice picture! Looks like a great rocket.

Just a couple quick comments for now, the L1720 file won't open for me, and in the M3100 file the main charge definitely went off like you'd expect. It went off at 900 feet, which is not a standard Raven value - did you custom configure it? But it did go off, so it seems whatever problem you had with the main was elsewhere?

Also is Endeavour 002 a bench test? Looks like it might be.
 

cvanc

Well-Known Member
Joined
Jul 24, 2012
Messages
1,303
Reaction score
27
Here are four files, the first is my Ultimate Endeavour Phred on a CTI L1720 White Thunder, then Phred again from last weekends T.H.O.R. BOB launch on a CTI M3100 (See Picture), and the next two are from my grandsons 4" Endeavour not sure of the motors.
Both of Phreds flights had a recovery failure. The Drogue came out but the main did not. I am trying to get dual deploy out of one tube and not having much luck.
I have one more file but it is to large to post so I will need to figure out how to reduce it.
Hmmm, something weird going on. I could not open the L1720 file directly from the forum but once I downloaded it to my PC it opened fine?!?

Anyway it has a bit of an odd look to the motor burn. It was a one motor flight, right? There is a very sharp spike in the accel data during the burn, and after that spike the G force is way down for the remainder of thrust. Did you spit a chunk of the nozzle or something?

Otherwise, looks like apogee charge went off a couple seconds late and it looks like the main charge did not change descent rate at all (did the main come out at apogee perhaps?).
 

Sailorbill

Well-Known Member
Joined
Jan 25, 2009
Messages
1,283
Reaction score
0
I don't know why that file won't open it doesn't for me either.
Yep I had it set at 900 because of the wind that day. The drogue deployed but the main got tangled up when the Teather fired. I am trying to get everything set up so it doesn't do that but so far no luck. I have all winter to get it figured out.
 

Sailorbill

Well-Known Member
Joined
Jan 25, 2009
Messages
1,283
Reaction score
0
I don't remember hearing any anomalies during the flight. I just looked at the nozzle and it looks OK.
The two flights on the Endeavour were on my Raven 1 while the two on Phred are on my Raven 3. I don't remember doing any bench test but I could have.

Adrian if you are monitoring this thread how do I reduce the size of an FIPa file. My L3 flight is 1.2 meg! Long slow descent, then it bounced around in a tree for a while before we could recover it.
 

cvanc

Well-Known Member
Joined
Jul 24, 2012
Messages
1,303
Reaction score
27
I don't know why that file won't open it doesn't for me either.
Try downloading it to your PC and then opening it from there. Worked for me.

I don't remember hearing any anomalies during the flight. I just looked at the nozzle and it looks OK.
You see what I'm talking about in the data, right? I don't know the why of it but it looks like there was a transient and after the transient the acceleration "stepped down" to a much lower level.

My guess is somehow the motor thrust actually stepped down like this suggests, but it's just a guess (mostly 'cuz I can't conceive any other possible cause for it).
 

Adrian A

Sponsor
TRF Sponsor
TRF Lifetime Supporter
Joined
Jan 22, 2009
Messages
2,258
Reaction score
233
I don't remember hearing any anomalies during the flight. I just looked at the nozzle and it looks OK.
The two flights on the Endeavour were on my Raven 1 while the two on Phred are on my Raven 3. I don't remember doing any bench test but I could have.

Adrian if you are monitoring this thread how do I reduce the size of an FIPa file. My L3 flight is 1.2 meg! Long slow descent, then it bounced around in a tree for a while before we could recover it.
I haven't tried making a fipa file smaller, but maybe winzip could compress it.
 

Adrian A

Sponsor
TRF Sponsor
TRF Lifetime Supporter
Joined
Jan 22, 2009
Messages
2,258
Reaction score
233
Try downloading it to your PC and then opening it from there. Worked for me.



You see what I'm talking about in the data, right? I don't know the why of it but it looks like there was a transient and after the transient the acceleration "stepped down" to a much lower level.

My guess is somehow the motor thrust actually stepped down like this suggests, but it's just a guess (mostly 'cuz I can't conceive any other possible cause for it).
It kind of looks like maybe the motor blew out a chunk of propellant near the end of the burn. There was an initial drop in thrust, then a big spike, and then the motor dropped down to a lower thrust. No response in the lateral axis, though, so I don't think it was a nozzle coming apart. Did you glue the grains into the liner?
 

CarVac

Well-Known Member
Joined
Feb 13, 2012
Messages
5,662
Reaction score
3
Hopefully after next weekend, I'll be able to post an exciting FIPa file that pushes the limits of even a 250G Raven...

I have a near-minimum mass rocket (~11 ounces without motor) lined up to fly on an I1299, which simulates to get 231 G's of acceleration.

I'm planning on using accelerometer integration for apogee detection, since I want to drill the bare minimum size vent holes possible. Thoughts?
 

cvanc

Well-Known Member
Joined
Jul 24, 2012
Messages
1,303
Reaction score
27
View attachment 103298


here is a AT J500 green flight in a giantleap elipse from yesterday
I don't know man; that file looks seriously wonked to me. Did the flight go as planned?

Lots of sharp, full-scale excursions on multiple channels - the rocket could't have actually done those things, right? Hopefully Adrian will look in on this one...
 

Sailorbill

Well-Known Member
Joined
Jan 25, 2009
Messages
1,283
Reaction score
0
Nope no glue the L1720 doen't require it.
This rocket lay in a soy bean field for almost three weeks before I found it.
 

atxcple

Well-Known Member
Joined
Feb 2, 2011
Messages
1,150
Reaction score
2
straight up flight perfect burn on the motor
 

cvanc

Well-Known Member
Joined
Jul 24, 2012
Messages
1,303
Reaction score
27
Welp, time for me to post my tale of woe.

I got one flight off at MWP X. The up part was spectacular. The down part? Not so much.

I got to just over 13,000 feet on a wicked sparky 'L'. The one Raven that survived reported just shy of one thousand miles an hour at burnout - not bad for a thirty pound bird.

All the deployment charges went off as planned, but unfortunately my main got wedged up inside the hollow (filament wound) nosecone and never deployed. After that, my luck took a turn for the bad. I hit smack in the middle of the only paved road for two miles. The impact destroyed my tailcone and brand new (1st flight) 75mm 5-G CTI case. I hit so hard I dented the road.

After that, my luck took a turn for the worse. As near as I can tell my rocket, laying in the road, got ran over by a car.

File and pics attached.


View attachment MWPcrash_B1407.FIPa

Wreckage.jpgroad.jpg2467_crop.jpg2493_crop.jpg
 

cerving

Owner, Eggtimer Rocketry
TRF Sponsor
TRF Supporter
Joined
Feb 3, 2012
Messages
3,551
Reaction score
796
Wow, bummer. Do you think a 1/4" ply bulkhead at the end of the nose cone would have prevented this? (I'm assuming you had a Kevlar lanyard on the fiberglass nose cone for shock cord attachment)

Sounds like something to look for when I get to my L2 rocket...

Welp, time for me to post my tale of woe.

I got one flight off at MWP X. The up part was spectacular. The down part? Not so much.

I got to just over 13,000 feet on a wicked sparky 'L'. The one Raven that survived reported just shy of one thousand miles an hour at burnout - not bad for a thirty pound bird.

All the deployment charges went off as planned, but unfortunately my main got wedged up inside the hollow (filament wound) nosecone and never deployed. After that, my luck took a turn for the bad. I hit smack in the middle of the only paved road for two miles. The impact destroyed my tailcone and brand new (1st flight) 75mm 5-G CTI case. I hit so hard I dented the road.

After that, my luck took a turn for the worse. As near as I can tell my rocket, laying in the road, got ran over by a car.

File and pics attached.


View attachment 103534

View attachment 103536View attachment 103537View attachment 103538View attachment 103539
 

CCotner

Well-Known Member
Joined
Sep 4, 2012
Messages
884
Reaction score
2

Sailorbill

Well-Known Member
Joined
Jan 25, 2009
Messages
1,283
Reaction score
0
I don't know what I did wrong but I think is fixed now.
 

cvanc

Well-Known Member
Joined
Jul 24, 2012
Messages
1,303
Reaction score
27
Wow, bummer. Do you think a 1/4" ply bulkhead at the end of the nose cone would have prevented this?
Any design that prevents the chute from getting rammed up into the hollow cone by the ejection charge would have prevented this failure mode. A bulkhead would work, or just fill the cone with expanding foam, etc.

My NC is heavy (~7lbs with ballast) but mostly hollow. It had come off too soon on an earlier flight using 4 x 2-56 shear pins. So I went to 8 x 2-56 shear pins which forced me to raise the amount of BP. See where this is heading? I ground tested of course but got lucky and the chute problem didn't happen for me there. Or is that UNlucky? LOL

That's terrible luck...so sorry!
Thanks; appreciate it. My biggest mistake? I went to the trouble of adding up how much this crash cost me. I do not recommend this exercise - it was depressing! :jaw:
 

cvanc

Well-Known Member
Joined
Jul 24, 2012
Messages
1,303
Reaction score
27
I don't know what I did wrong but I think is fixed now.
Yup, it opens just fine now. Looks like a heckuva flight! Twelve minutes hang time; how far did you have to go to get it back?

Your motor... was it some kind of stepped thrust type? See the large acceleration for about half the burn followed by a much lower shelf? Just curious...
 

Sailorbill

Well-Known Member
Joined
Jan 25, 2009
Messages
1,283
Reaction score
0
Yup, it opens just fine now. Looks like a heckuva flight! Twelve minutes hang time; how far did you have to go to get it back?

Your motor... was it some kind of stepped thrust type? See the large acceleration for about half the burn followed by a much lower shelf? Just curious...
Hang time due to main at apogee, then it ended up a tree.
Motor was a CTI 75MM 6438M1300-P Imax Dual Thrust. About 640 lbs of thrust for 1 sec. then it averages about 225 lbs for nearley Four seconds.

BOBlaunch6inL3-00000003.jpg

Launch Picture.
 

Rocketjunkie

Addicted to APCP
Joined
Jan 19, 2009
Messages
3,977
Reaction score
230
I had a second ballistic recovery Saturday due to Raven failure. The Formula 98 impacted in the far south field after a long slow boost to an estimated 6000 feet on a K160. Impact sheared off the supercap, beeper, and terminal block. I was able to connect power and the FIP was able to connect to the Raven. Although the Raven was beeping correctly on the pad, it never detected liftoff and there was no data file. I was able to read the 2 previous flight data files from the Raven. If my twist and tape down wires hadn't been sheared off by impact, there would have been power - the battery was still at 9.24V.
The first failure was in June with a Raven version 1, this was a Raven version 2 (on it's third flight).
Video of the boost:[YOUTUBE]85eddPge_BI[/YOUTUBE]
 

blackbrandt

That Darn College Student
Joined
Mar 18, 2012
Messages
9,125
Reaction score
39
Video of fight is here [video=youtube;qGDtLxtOEfs]http://www.youtube.com/watch?feature=player_embedded&v=qGDtLxtOEfs[/video]
All I see is a flight of a rocket, not some kids swinging their fists at each other...danget. :rofl:
 

cvanc

Well-Known Member
Joined
Jul 24, 2012
Messages
1,303
Reaction score
27
The Formula 98 impacted in the far south field after a long slow boost to an estimated 6000 feet on a K160. Impact sheared off the supercap, beeper, and terminal block. I was able to connect power and the FIP was able to connect to the Raven. Although the Raven was beeping correctly on the pad, it never detected liftoff and there was no data file.
Oh man, that's terrible. Sympathies on your loss.

In a case like this, where there is no file to look at, how do you go about sorting out what went wrong? I'm not really sure but maybe you could post pictures of your setup and wiring to continue the conversation? (If any pictures exist, that is.)

Did you like the rocket, will you build another? A few posts up I shared the crash of my Competitor 4. I've decided I really like that rocket, it fits my usual flying field very well - not to mention my car! - and I will replace it with another. There's a couple parts I can salvage from the wrecked one.
 
2
Top