View attachment 100030
Here's one. Rocket was a LOC Viper IV, 2 F240's airstarting 2 D12's. Check the velocity profile
Tom, in the file you posted which values are the altitude?
View attachment 100030
Here's one. Rocket was a LOC Viper IV, 2 F240's airstarting 2 D12's. Check the velocity profile
The default if you open the file shows only acceleration and barometric altitude. You need to select other parameters separately. Peak altitude was about 2100 feet. (Hold CTRL and select velocity (accel ft/sec) for the velocity curve without clearing the others.)Tom, in the file you posted which values are the altitude?
Thank you. I had hoped the file included altitude values so that I can import the data in to my software.
I know the information is there, but you should contact Adrian for the exact file format.Thank you. I had hoped the file included altitude values so that I can import the data in to my software.
Here is the Raven3 FIPa file from my flight today. The rocket is a modified Wildman Jart, with an altimeter in the (fully seperable) nose-cone shoulder (or coupler tube). The strange thing about this flight is that it appears that both the apogee and main channel fired at apogee. The nosecone is hollow and contains the ejection charge, chute, etc. There is burnt black powder inside the nosecone, and the shock cord affixed to the metal nose tip is blackened, so I know the charge fired. If it had been some other sort of separation, the nosecone deployment charge would have fired OUTSIDE the nose cone, and none of this evidence would have been left behind.
The trace shows some curious things:
1) The Barometric pressure increases sharply when the apogee (aft) charge is fired. This suggests to me that I have "leaks" in the double-bulkhead at the aft end of the altimeter bay. It does not look like this negative-going altitude spike went low enough to trigger the firing of the main charge. So what did? The main charge voltage dipped, but I thought this was a side-effect of #2 below. Given that the charge actually *fired* (as evidenced by the soot and discoloration in the nosecone), then this must actually be due to the channel firing.
2) Battery Voltage sagged pretty badly when the apogee charge was fired. The leads may be too long on this battery. I need to run some ground tests to see what caused this.
So, anyone know for certain what caused the main charge to fire at apogee?
View attachment 100801
P.S., the more I look at this the more mystified I become. The main channel *clearly* fires much later in the trace. The voltage on that channel only appears to dip at apogee - and I am all but convinced this is due to the battery voltage sag (they look almost identical). The mysterious part is that the chute is bright orange, and was clearly deployed at apogee. I thought it was a mechanical separation due to shock (sheared the nosecone nylon shear pins when the aft shock cord reached full extension). The only problem with this is that the main ejection charge had relatively short leads, and the charge canister was not affixed inside the nosecone in any way. It is impossible for it to have fired later and still have been inside the nosecone. Yet there is all that burnt evidence in the nosecone (and smell of spent black powder).
Here is the Raven3 FIPa file from my flight today. The rocket is a modified Wildman Jart, with an altimeter in the (fully seperable) nose-cone shoulder (or coupler tube). The strange thing about this flight is that it appears that both the apogee and main channel fired at apogee. The nosecone is hollow and contains the ejection charge, chute, etc. There is burnt black powder inside the nosecone, and the shock cord affixed to the metal nose tip is blackened, so I know the charge fired. If it had been some other sort of separation, the nosecone deployment charge would have fired OUTSIDE the nose cone, and none of this evidence would have been left behind.
The trace shows some curious things:
1) The Barometric pressure increases sharply when the apogee (aft) charge is fired. This suggests to me that I have "leaks" in the double-bulkhead at the aft end of the altimeter bay. It does not look like this negative-going altitude spike went low enough to trigger the firing of the main charge. So what did? The main charge voltage dipped, but I thought this was a side-effect of #2 below. Given that the charge actually *fired* (as evidenced by the soot and discoloration in the nosecone), then this must actually be due to the channel firing.
2) Battery Voltage sagged pretty badly when the apogee charge was fired. The leads may be too long on this battery. I need to run some ground tests to see what caused this.
So, anyone know for certain what caused the main charge to fire at apogee?
View attachment 100801
P.S., the more I look at this the more mystified I become. The main channel *clearly* fires much later in the trace. The voltage on that channel only appears to dip at apogee - and I am all but convinced this is due to the battery voltage sag (they look almost identical). The mysterious part is that the chute is bright orange, and was clearly deployed at apogee. I thought it was a mechanical separation due to shock (sheared the nosecone nylon shear pins when the aft shock cord reached full extension). The only problem with this is that the main ejection charge had relatively short leads, and the charge canister was not affixed inside the nosecone in any way. It is impossible for it to have fired later and still have been inside the nosecone. Yet there is all that burnt evidence in the nosecone (and smell of spent black powder).
If you scale the battery, apogee and main voltages so that they both go 0-5V, you can see that the main continuity voltage just dipped along with the battery voltage. Also, the current was reading over 13 Amps during the whole 1-second firing. So you had a short during the apogee firing, but the main output was not switched on until later when AGL < AGL1. What kind of battery and igniter did you use at apogee? The accel data looks like the main inflated at apogee.
You can right-click in the parameter window to copy or save the data for import somewhere else.
If you scale the battery, apogee and main voltages so that they both go 0-5V, you can see that the main continuity voltage just dipped along with the battery voltage. Also, the current was reading over 13 Amps during the whole 1-second firing. So you had a short during the apogee firing, but the main output was not switched on until later when AGL < AGL1. What kind of battery and igniter did you use at apogee? The accel data looks like the main inflated at apogee.
View attachment 100898
I want to make this one a mystery but ill leave some hints.
-M1297
-Lvl3 attempt
-3" Rocket
Question is what happened and why, anyone have guesses? This flight was in the spring and I know what I think happened and will share soon.
View attachment 100898
I want to make this one a mystery but ill leave some hints.
-M1297
-Lvl3 attempt
-3" Rocket
Question is what happened and why, anyone have guesses? This flight was in the spring and I know what I think happened and will share soon.
The "PS" in my post was an edit - after I had done exactly what you suggest here. I could see that the battery voltage sagged heavily, and that the main channel voltage was just following this envelope.
It didn't occur to me, however, to check the current draw. Wow, 14A! No wonder the voltage sagged. I am using a 600mah battery with a connector that mates to the power perch. I use the mounting screws of the perch to power my BRB beacon. The ejection canisters I am using are the mini ones from Pratt hobbies, which I believe use a crushed grain-of-wheat lamp as the igniter. The 14A draw did not last for the entire 1 second, though. If you expand the timescale it lasted only about 0.4 seconds. Still, half a second of 14A is ridonculous.
Since there wasn't anything visible in the lateral axis before the disintegration, that indicates that it wasn't the usual shred cause of coupler failure, instability, or fins. That plus the consistent positive-G impulse during the burn suggests to me that it was a CATO.
That little spike lines up in time with your apogee charge going off. Somehow the baro sensor is 'seeing' your ejection charge... at least a little bit. AV bay may need better sealing? Hard to say as it does not seem to be very much. I'd guess a small amount is not a problem?
On the Weasel it looks like your main came out at ~2600 feet but the altimeter didn't fire the main charge until 480 feet. Drag separation, maybe?
The other interesting thing is how utterly smooth the baro data from the Weasel is; really nice. But the Wildchild baro data is rougher, more granular, "busier". Some of the other files posted here have that look too. I wonder what it means? Crosswind in the vent holes? Vent holes too small? Too big? I have no idea.
Adrian, are you saying some shreds show an undamped, increasing oscillation in the lateral axis data, up to the moment of airframe failure? Very interesting.
Yes. People sometimes ask why I bother with recording the lateral accel axis when it's not used in any deployment logic, and it's for cases like this.
Rocket- Formula 54 with 38mm engine tube. Converted Nose cone coupler to av bay. 1st flight on Estes F50-4T, 290ft, 2nd flight on Cesaroni H123 Skidmark w/motor ejection and apogee and 700' charges [L1 cert] 2300' =/-, 3rd fl Cesaroni H123 Skidmark with apogee and 700' charges 2300' =/-, 4th fl Cesaroni H123 Skidmark with apogee and 700' charges 1900' =/- [bad spin during flight]. 3rd and 4th flights had forward and aft av bay plates sealed against charge gasses.
Dick Moran
NAR 6306 L1
Tri 14074 L1
MDRA 254
I didn't get much video from the ground but I had a keychain cam aboard[YOUTUBE]Jxgc-HIaAkM[/YOUTUBE]This flight was 'interesting'. 2 J500, 3 H178, 2 H73 cluster.
Rocket- Formula 54 with 38mm engine tube. Converted Nose cone coupler to av bay. 1st flight on Estes F50-4T, 290ft, 2nd flight on Cesaroni H123 Skidmark w/motor ejection and apogee and 700' charges [L1 cert] 2300' =/-, 3rd fl Cesaroni H123 Skidmark with apogee and 700' charges 2300' =/-, 4th fl Cesaroni H123 Skidmark with apogee and 700' charges 1900' =/- [bad spin during flight]. 3rd and 4th flights had forward and aft av bay plates sealed against charge gasses.
Dick Moran
NAR 6306 L1
Tri 14074 L1
MDRA 254
This flight was 'interesting'. 2 J500, 3 H178, 2 H73 cluster.
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