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cvanc

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What I did not expect is this "self healing" scenario. So was wondering if anyone had seen something similar?
Yes, all the time. It's actually common. The only kind-of-odd thing with your file is how long it took to re-establish continuity, roughly 50 (fifty) seconds. In my experience it's usually just a second or two. Not sure what that implies, but it's hard to imagine this is something to worry about.
 

timro

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I'm attaching a flight that had an issue with main deploying during the apogee deployment. Rocket is 38mm MD and similar in design to another where I had several successful flights with the Raven 3 / 38mm av bay. My conditions for main deployment are T>Tval, AGL<AGL1 (900'), pressure increasing.

View attachment MDX3_H170-160806.FIPa

This altimeter flew a few hours earlier with identical settings and performed as expected. The last data value Vmain = 4.341V before it drops seems odd as the standard 1S lipo that fits into the bay never hits this voltage.

Any suggestions? I haven't had time yet to run a flight test with LED's attached to the terminals but will in the next day or so.
 

kjs

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I'm attaching a flight that had an issue with main deploying during the apogee deployment. Rocket is 38mm MD and similar in design to another where I had several successful flights with the Raven 3 / 38mm av bay. My conditions for main deployment are T>Tval, AGL<AGL1 (900'), pressure increasing.

View attachment 298555

This altimeter flew a few hours earlier with identical settings and performed as expected. The last data value Vmain = 4.341V before it drops seems odd as the standard 1S lipo that fits into the bay never hits this voltage.

Any suggestions? I haven't had time yet to run a flight test with LED's attached to the terminals but will in the next day or so.
Tim, I verified your config from the flight bits and agree your settings show AGL < AGL1 (~900ft) but it is interesting that if I zoom in on the apogee part of the graph and select those bits, it indicates that the Raven didn't think it was below 900 ft (so likely didn't fire the main charge by way of logic):

mainDeploy..jpg

I'm wondering if there was a wiring short - or some type of short now on the board. Or else whatever caused the odd spike in voltage also caused the deployment - by not by way of the Raven saying 'fire Main'...

I'd be interested in what a test flight with LEDs shows when you get a chance...

Thanks!
 

timro

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I'd be interested in what a test flight with LEDs shows when you get a chance...

Thanks!
Hi Kevin,
The test run looks nominal. I am wondering if there was some kind of shift / jolt caused during the apogee charge firing that might have caused a short or some other issue. I do have the allthread close to the raven board wrapped with electrical tape to prevent shorts from that avenue.

View attachment Ravent5.FIPa

I'm thinking one more test flight is in order before I throw it way up there.
 

kjs

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Hi Kevin,
The test run looks nominal.

I'm thinking one more test flight is in order before I throw it way up there.
Actually, if you add the vbatt, vmain and vapogee to the graph but scale them all the same (right click, Edit... on the axis label for each), then it appears that vApogee is only ~2.47 volts vs 4.1 v for vBatt and vMain... something seems odd about your apogee channel now...

mainDeploy.2.jpg

What is the serial number for your Raven3 - I'll try to check the original test flight data later this week when I am back home.

Thanks!
 

timro

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Actually, if you add the vbatt, vmain and vapogee to the graph but scale them all the same (right click, Edit... on the axis label for each), then it appears that vApogee is only ~2.47 volts vs 4.1 v for vBatt and vMain... something seems odd about your apogee channel now...

View attachment 298600

What is the serial number for your Raven3 - I'll try to check the original test flight data later this week when I am back home.

Thanks!
The lowered voltage on vApogee is an artifact of the test LED attached. That particular one seems to draw a small current and is working as a voltage divider due to the internal resistor. If I just have the other light on vApogee, it looks typical.

Serial # is 2522

Here's the previous flight of that day (powered by a 2S lipo - more space on the sled). The vApogee and vMain channels working all as expected.

View attachment XCelerator_K1440_BR-160806.FIPa
 

kjs

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For my test setup, I use the old fashioned Christmas lights (not the LED kind) so that they sink a lot of current (much closer to reality of an ematch vs a low current LED or LED with resistor). ... or at the cost of two ematches, I have hooked up live matches and run the FIP test just to be sure. This latter test is especially exciting if you put the business end in a coffee can on your desk and don't tell your wife sitting in the same room what you are doing... :)
 

SpaceManMat

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Looks like your main shook out at apogee? Also, your rocket was still recording positive Gs during the coast. I'd recommend doing a user re-calibration of the altimeter with the FIP, especially since this is a 250G single-axis version, so any cal errors get magnified.
Adrian would it be a good idea during power to check if the acelorometrs are actually giving reasonable data? If not then the unit could either do a rough self calibrate or simply not go into ready for launch mode?
 

Leo

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Could someone post a file of a successful 1.5+ MACH flight. Thanks.
 

kjs

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In the process.. we had a competition to see who could push the 24mm Tomahawk the highest... After retrofit (but still plastic fins) we had a 38mm J motor that i think reached mach ~2... getting the data from the 'pilot'.... i'll let you know later and post it...
 

Leo

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I'd really appreciate it if someone could post a MACH+ flight file.
 

kjs

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sorry for the delay Leo - i'm pinging the 'pilot' as well as Adrian for their flight data. i probably have it but am in temp living now so not sure if it is on the hard drive i pulled from my other desktop or not...

/kjs
 

kjs

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I'd really appreciate it if someone could post a MACH+ flight file.
Leo, I'm waiting on data from the flier that had a J350 (I think) in an Estes Tomahawk modified for 38mm... but did find this flight from 2011 that was a minimum diameter M flight which got well past mach. I forget the specifics of this flight although it looks like the main came out late even though pyro apogee fired near the peak.

View attachment 2011-09-03-Target2C-Raven-M1300.FIPa

Sorry again for the delay.

/kjs
 

Leo

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Thanks for the file.

To get the RAW altitude numbers I click on "[Altitude (Baro-Ft-AGL)], right click "save data" -> "time paired". Is this correct?
 

kjs

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Thanks for the file.

To get the RAW altitude numbers I click on "[Altitude (Baro-Ft-AGL)], right click "save data" -> "time paired". Is this correct?
Yes, and since different measurements happen at different points in time, you will get a time column for every variable column. The flattened tries to give an aligned view over time but for single variables, the time paired is easier to work with I think.
 

kjs

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ok, I got the data for the Estes Tomahawk modified for 38mm and flying a J570... Peak altitude was around 12K feet and top speed ~971 MPH... ! And yes this was with the stock plastic fins (with some special plastic cement to help hold them on). The ARS (Albuquerque Rocket Society) would occasionally have contests for taking a stock kit and - within guidelines such as "exterior profile and material must stay the same" - would see who could push the envelope. There was also a Big Daddy contest where we had to keep the Balsa fins... Winner put a 54mm motor in it - lost some fins but still won; sadly I don't have that data file...

Anyway the Featherweight Raven / Estes Tomahawk / Aerotech J570 file is here (sorry it would not upload as a FIPa as it is the older text format but if you download it, unzip it and then use FIP to load it, it should display fine).

View attachment 2009-04-18-Flt2-J570.zip

Thanks!
 

kjs

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I started a separate thread for a special flight where the Raven was used to record chamber pressure data in flight. It was someone else's flight but I thought it too cool to not post...
 

patelldp

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Had a pretty cool flight of my 2" diameter 2-stager on a 29-3G EX motor staging to a 29-2G EX motor. This was my first time using a stage separation charge instead of drag separation of motor ignition separation. It was also the first time that the booster had an altimeter in the interstage to allow the use of a plugged booster motor.

I made the stage separation charge on the field and therefore didn't have a scale to measure it. This resulted in a charge that was rather "adequate" and made itself known in flight with an incredibly loud BANG when it went off. The Raven data doesn't disappoint, displaying a 93.48 G spike!!! The main didn't deploy due to the charge being too small (oh the irony), but there wasn't any damage.

Small 2 stagers are a good time, I will expand on this and build a 3 stager for next year.



View attachment 10-8-16_Stager_29-3GPJ_29-2GPJ_CTRA.FIPa
 

manixFan

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Could someone post a file of a successful 1.5+ MACH flight. Thanks.
OK, so a bit late but here are two recent Mach+ flights from BALLS 25 at Black Rock desert. A CF 54mm Mongoose on a CTI L935 to about 23,500' and Mach 2.3, and a ShadowAero Raven3 on a Loki K627 to about 15,100' and Mach 1.5 ish.

Pretty clean data for both flights. The descent rate for the Raven3 is quite high but it recovered fine. Dave Triano says the thing can recover on just a drogue and I believe it on most surfaces. The descent rate for the Mongoose is more typical.

Both rockets recovered in good condition.


Tony

View attachment Raven3 on K627 R.FIPa
View attachment Mongoose L935 - R.FIPa
 

Buckeye

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I hope to be a Featherweight Raven owner soon and enjoyed reading this thread.

I have a request. I would like to test my skills in backing out thrust curve and drag coefficient from the data. Can someone with a good vertical flight include the rocket diameter, pad mass, and burnout mass along with the FIPa data file? Mach flights preferred. Thanks much!
 

cvanc

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Hi troops-

Here's a weird one I'd like to get eyes on.

Flew at Bong Saturday; Competitor 4 with an Aerotech K-1000 Blue Thunder. It went at least 4,000 feet and (this is important) all 4 BP charges went off as planned. But the Raven file only has seven seconds of recording in it. The flight was more like two minutes.

Those 7 seconds have some pretty squiggly data. None of the traces really look normal.

When I picked the rocket up off the ground it did not beep out the altitude, which is unusual. I opened the AV bay about an hour after recovery and the Raven was running (LEDs were lit).

Remember all of my ejection events WORKED including two that were programmed to occur very late in the flight (main at 1,000 and backup main 1.5 seconds later - I both saw and heard these charges go off).

I'm struggling to reconcile "screwy data file" and "perfectly normal flight". Any ideas on this one?

View attachment Flight 41 bank2.FIPa
 

Adrian A

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Hi troops-

Here's a weird one I'd like to get eyes on.

Flew at Bong Saturday; Competitor 4 with an Aerotech K-1000 Blue Thunder. It went at least 4,000 feet and (this is important) all 4 BP charges went off as planned. But the Raven file only has seven seconds of recording in it. The flight was more like two minutes.

Those 7 seconds have some pretty squiggly data. None of the traces really look normal.

When I picked the rocket up off the ground it did not beep out the altitude, which is unusual. I opened the AV bay about an hour after recovery and the Raven was running (LEDs were lit).

Remember all of my ejection events WORKED including two that were programmed to occur very late in the flight (main at 1,000 and backup main 1.5 seconds later - I both saw and heard these charges go off).

I'm struggling to reconcile "screwy data file" and "perfectly normal flight". Any ideas on this one?
I suspect that the flight data file you attached came from just before or just after the end of your flight, and the flight you're looking for is the one before that, flight 40 if I interpret your filename correctly. In flight 41 the baro altitude is only decreasing during your file, and the 7 second duration is about how long it takes the Raven to figure out that the baro sensor says that it's on the ground. The acceleration spikes in the file look like a ground bounce. Your deployment charge continuity are all showing 0 volts. So I think you had a power loss or something else to cause a reset, followed by some kind of impact that the Raven interpreted as liftoff.
 

cvanc

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Hi Adrian and thanks for the analysis. Here is flight 40 from memory bank 1. It ends kind of abruptly after the 4th (backup main) charge fires, which seems to agree with your idea that both of these files come from the same flight.

Loose battery connection, maybe?

View attachment Flight 40 bank1.FIPa
 

Scott S

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kjs

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Attached is a flight from last week that had a deployment at burn out. I am pretty sure I know why but would like a second opinion.
Where was your vent hole - did you have a vent hole? According to the data, altitude was decreasing (pressure increasing) up until burnout ( at minus 40 feet!) then it (presumably was better vented) and realized it was at ~300 feet. so to me it looks like an odd venting issue or questionable baro sensor (but the baro seems to work after separation making me question the venting).

note that the highlighted area at liftoff where it looks like it is descending...

1621736826974.png
 

SpaceManMat

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Where was your vent hole - did you have a vent hole? According to the data, altitude was decreasing (pressure increasing) up until burnout ( at minus 40 feet!) then it (presumably was better vented) and realized it was at ~300 feet. so to me it looks like an odd venting issue or questionable baro sensor (but the baro seems to work after separation making me question the venting).

note that the highlighted area at liftoff where it looks like it is descending...

View attachment 465558
Kevin, yes a vent issue was the conclusion I came to. It’s an X Wing, they have an unusual shaped nose. My plan is to relocate the vent to the back of the nose which is shaped more like a traditional nose cone, however I was thinking I should probably look at changing the configuration of the Raven to lock out the baro deployment until a reasonable time in case this does not resolve the issue. Any thought on how this is best achieve? I was thinking either lower the Mach lockout setting or perhaps a time based option.


Nose cone - vent
on Flickr
 

kjs

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So, we have flown vent holes in the nose cone to ~mach 2 - but that hole with the lower flat plate probably did something weird for pressure... you could probably just change it to accelerometer for the apogee and be ok, but we can try to think of other lock out options if you want...

If you want to experiment... try the vent on the left side where there is no "blast plate" below it... I think it was the flat thing below your vent hole that was the problem...

[edit - re reading and you already thought of relocating the vent hole... I think that is all you likely need but we can talk more about other lock outs if you want...]
 
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