O3400 Min Diameter L3

[airforcetp1991]

Nice! Look kinda familiar-

View attachment 463156

View attachment 463157

Very well done! Any lessons learned from that build for the AvBay/Co2 setup? I was thinking of using the terminal blocks but since I am less concerned with reusability I liked the simpler setup of the wire retainers.

Tony

 

[watheyak]

I wouldn't use the terminal blocks if I did that av-bay again. They just seem too fragille and prone to getting knocked off the plate.

Other than that, this rocket met an unfortunate end. Much was learned, just not about the av-bay or the CO2.

 

[airforcetp1991]

I wouldn't use the terminal blocks if I did that av-bay again. They just seem too fragille and prone to getting knocked off the plate.

Other than that, this rocket met an unfortunate end. Much was learned, just not about the av-bay or the CO2.

Sorry to hear that, that’s how we learn sometimes though. That was the fate of my first L2 attempt…

 

[Siya]

Here is my Avbay for 4” 12” long coupler. 2 AIM Xtras for tracking and deployment.

 

[wbeggs]

Nice setup! Hope everything goes great with the flight!

 

[airforcetp1991]

Here is my Avbay for 4” 12” long coupler. 2 AIM Xtras for tracking and deployment.

That looks like a good setup. Did you think about shortening the coupler, looks like you don’t need all the room?

 

[mrwalsh85]

I would suggest getting a buddy to track and locate your booster. It takes much of the stress off sustainer recovery. Get somebody else on camera duty as well.


Write down the landing coordinates provided by the tracking systems. I have seen both a laptop and a phone with the backup of the location data go flat in the field during recovery (not mine). Don't need a battery to keep numbers written on a piece of paper .

When I was flying my TeleGPS aboard a SLI team's rocket, I recorded the screen (Screen capture) for the duration of the flight. I thought it'd be cool to have the audio output recorded. This is another way to capture your data - you can make sure you've saved the data and review it in your video. I will probably start doing this just because.

 

[Siya]

That looks like a good setup. Did you think about shortening the coupler, looks like you don’t need all the room?

I plan on using the extra room for a go pro and runcam 2

 

[airforcetp1991]

When I was flying my TeleGPS aboard a SLI team's rocket, I recorded the screen (Screen capture) for the duration of the flight. I thought it'd be cool to have the audio output recorded. This is another way to capture your data - you can make sure you've saved the data and review it in your video. I will probably start doing this just because.

I like this idea, until now I have taken screen shots on the way up and down as a backup but the video will be much better. The tracking app has been very stable so I am not worried about it crashing but insurance never hurts.

 

[airforcetp1991]

I plan on using the extra room for a go pro and runcam 2

Nice, this will be my first time using an on board camera as well. I didn't want to add the complexity required to have it take video of the ascent but I plan to have my Runcam5 in the payload section for some good apogee/descent footage. I figure it is worth the 60g of extra weight..It will be attached to the shock cord to film the descent.

Tony

 

[plugger]

When I was flying my TeleGPS aboard a SLI team's rocket, I recorded the screen (Screen capture) for the duration of the flight. I thought it'd be cool to have the audio output recorded. This is another way to capture your data - you can make sure you've saved the data and review it in your video. I will probably start doing this just because.

I can understand why you'd want to do this Mike, but in application with Altus Metrum products I don't think it's necessary. Both AltusUI and AltusDroid applications by default save every packet of telemetry data they receive. You can find this flight log in the default directory where all telemetry and eeprom (downloaded from the unit) files are stored. The telemetry stream/flight log file is stored in the .telem file whereas you eeprom file comes when you download the full flight log from the device you're using.

You can then use the AltusUI software "Replay flight" feature to play back the .telem file. The audio will work identically to the flight audio as well.

 

[mrwalsh85]

I can understand why you'd want to do this Mike, but in application with Altus Metrum products I don't think it's necessary. Both AltusUI and AltusDroid applications by default save every packet of telemetry data they receive. You can find this flight log in the default directory where all telemetry and eeprom (downloaded from the unit) files are stored. The telemetry stream/flight log file is stored in the .telem file whereas you eeprom file comes when you download the full flight log from the device you're using.

You can then use the AltusUI software "Replay flight" feature to play back the .telem file. The audio will work identically to the flight audio as well.

Sure, that works. But it doesn't help you in the event of inadvertently closing the app, turning your phone off (to put it in your pocket), etc., thus losing the gps coordinates. I don't recall being able to put my phone in my pocket and then get it back out to review the coordinates, I think I keep losing my data at that point (basically you're terminating your connection to your TeleBT at that point, then trying to reconnect). Besides, I shared the video with the SLI team who thought it was cooler than all get out.

In short, the screen record is only intended for reviewing data while you're on the ground and in the phase of going off to find your rocket. There might have been an anomaly during the recovery process, and you'd need to review the data at that event. For instance, you suddenly lose power (and thus, lock) while you're at 4,000 ft AGL. "What heading was it on? At what GPS coordinates did we lose lock? We need to have a starting point for our canvass!" review screen record "oh, whew, it was on this path when we lost lock so we should be able to start at this spot and then work in the direction it was heading at that point in time"...

 

[mrwalsh85]

I just opened up my UI on my iPhone and found two tracks. But I don't see a way to scroll through GPS coordinates over time, velocity at a given time, etc... So that is where a screen record comes in handy.

 

[plugger]

Sure, that works. But it doesn't help you in the event of inadvertently closing the app, turning your phone off (to put it in your pocket), etc., thus losing the gps coordinates. I don't recall being able to put my phone in my pocket and then get it back out to review the coordinates, I think I keep losing my data at that point (basically you're terminating your connection to your TeleBT at that point, then trying to reconnect). Besides, I shared the video with the SLI team who thought it was cooler than all get out.

In short, the screen record is only intended for reviewing data while you're on the ground and in the phase of going off to find your rocket. There might have been an anomaly during the recovery process, and you'd need to review the data at that event. For instance, you suddenly lose power (and thus, lock) while you're at 4,000 ft AGL. "What heading was it on? At what GPS coordinates did we lose lock? We need to have a starting point for our canvass!" review screen record "oh, whew, it was on this path when we lost lock so we should be able to start at this spot and then work in the direction it was heading at that point in time"...

I just opened up my UI on my iPhone and found two tracks. But I don't see a way to scroll through GPS coordinates over time, velocity at a given time, etc... So that is where a screen record comes in handy.

Ah, I see where the problem lies. You're running the iPhone port of AltOS. I've never used an iOS device for Altus telemetry, nor do I plan to. TBH I don't use TeleBTs either.

If I'm going to be flying 'out of sight' (ie, over a mile AGL) I run the following setup:

• Teledongle connected via USB-OTG cable to my Pixel, with a 5 element yagi on the teledongle
• Teledongle connected to a laptop running Altos UI with an omnidirectional whip antenna
• Yaesu VX-8GR connected to the same laptop via serial that's outputting to a terminal with logging enabled. I configure my TeleGPS units to broadcast an APRS packet every 5 seconds as an entirely independent (from a receiver perspective) backup tracker

That way I've got two portable devices for tracking my rocket and three for receiving telemetry/APRS. You're correct that there's no way to replay a flight on mobile, hence me stating that you'd replay the flight in AltusUI. I didn't realise that iOS port was called the same thing. Realistically it probably shouldn't be but I'm most likely splitting hairs.

Anyway, back to your concerns about inadvertently closing the app, etc, that's not an issue with the AltusDroid app. I just opened mine up to have a look, by default it always displays the last known good GPS coordinates regardless of whether it's connected to a receiver, tracker, etc.



As you can see above, I'm not connected, it's been 262 days since I received my last telemetry packet, I've got a target lat and lon, and distance and bearing to target. I've only recently bought a Lenovo 7" tablet to use instead of my Pixel as I find USB-C inferior to MicroUSB in our specific use case as USB-C isn't a positively retained connector like MicroUSB is. Last time I used the thing 'for real' I had the USB-C connector fall out multiple times. I had my phone screen cut off as well. Yet all I needed to do was to unlock my phone and my AltusDroid screen was open (but displaying 'not connected'). I'd replug in my OTG cable with the TeleDongle attached and I'd immediately be back in the tracking game. And honestly I find that if I've had a loss of telemetry the most value lies in having the last known-good packet, not the entire flight telemetry file.

 

[airforcetp1991]

GoPro test went well at the local launch this weekend. I should have had the camera at a better angle to capture more of the ascent and not the ground but I think the 2.7k 120fps is a good setting choice. This was a 47G launch so definitely a camera challenge.

More importantly make sure you double check your launch rails. IDK if this was an old rail or if I just didn't tighten the angle adjust enough but it is clear in the slo-mo that the rail moved WAYYY too much. Rocket flight was very straight but it could have easily not been.

- Slo-Mo







View attachment IMG_9398.mov

 

[JimJarvis50]

GoPro test went well at the local launch this weekend. I should have had the camera at a better angle to capture more of the ascent and not the ground but I think the 2.7k 120fps is a good setting choice. This was a 47G launch so definitely a camera challenge.

More importantly make sure you double check your launch rails. IDK if this was an old rail or if I just didn't tighten the angle adjust enough but it is clear in the slo-mo that the rail moved WAYYY too much. Rocket flight was very straight but it could have easily not been.

Tony, I agree with your comment about the importance of checking the launch rail. In this case, it appears to me that the pad and rail were inadequate for your flight. It is your obligation to ensure that the pad is sufficient, period. It also appears to me that a rail button came off during the flight. If that had not happened, it's hard to say where this rocket might have gone.

If you are able to launch your O3400 flight, let this flight be a lesson with respect to pad design. I can tell you that on my larger flights, the design of the pad gets as much consideration as the rocket itself. I have seen many examples where it is apparent that the flier hasn't given much consideration to the pad that they are flying from.

Jim

 

[airforcetp1991]

Tony, I agree with your comment about the importance of checking the launch rail. In this case, it appears to me that the pad and rail were inadequate for your flight. It is your obligation to ensure that the pad is sufficient, period. It also appears to me that a rail button came off during the flight. If that had not happened, it's hard to say where this rocket might have gone.

If you are able to launch your O3400 flight, let this flight be a lesson with respect to pad design. I can tell you that on my larger flights, the design of the pad gets as much consideration as the rocket itself. I have seen many examples where it is apparent that the flier hasn't given much consideration to the pad that they are flying from.

Jim

You are correct, the aft rail guide did separate from the rocket about 2/3 of the way up the rail. I make no excuse for not checking the pad more thoroughly. I have launched 2 similar size motors from the same type of rail with this rocket and all of them were clean looking at the footage again. That makes it clear to me that I did not do my part. This will definitely be a lesson for me!

What have you used for launch tower design styles with your larger launches? I am looking now at the Attebery style and a 1515 extrusion style of tower.

Tony

 

[JimJarvis50]

You are correct, the aft rail guide did separate from the rocket about 2/3 of the way up the rail. I make no excuse for not checking the pad more thoroughly. I have launched 2 similar size motors from the same type of rail with this rocket and all of them were clean looking at the footage again. That makes it clear to me that I did not do my part. This will definitely be a lesson for me!

What have you used for launch tower design styles with your larger launches? I am looking now at the Attebery style and a 1515 extrusion style of tower.

Tony

Tony,

I have a pad/rail that I have built that lets me transport it in 6' sections. It has guy wires for support and I can raise the rocket with a winch. No one is around or under my rockets when I raise them. Beyone this, the details of what I do are not important.

One piece of advice I would offer is that I would never fly anything above an M motor on the equipment supplied at large launches. If I had the time, I could give you many examples where fliers regretted doing this. Balls in particular is a bring-it-yourself launch. Obviously, people have flown O motors from the supplied pads at Balls, but I would never even consider doing that. I want to know and control the characteristics of the pad in advance.

I'm not sure what an Attebery style is or a 1515 extrusion style of tower. If you are using a tower and not guides, then you will need to make or borrow the tower. The biggest issues I have seen with towers is a failure to secure the bottom of the tower, particularly if the motor exhaust can undercut the ground. Towers are often too short. When they are long enough, the guides sometimes are not strong enough to contain the rocket.

Jim

 

[Siya]

Caztek Engineering makes incredible launch towers. The current O3400 record rocket flew of a Caztek tower.

 

[FredA]

Wow - relegate that pad in the video to mid-power only.
Not even sure it's fit for that - you can see the wind blow it at the end.
That is insanely bad.

With a usual limit of 14" per side, flying out of the center of a triangular tower is for small-finned rockets only.

 

[airforcetp1991]

Caztek Engineering makes incredible launch towers. The current O3400 record rocket flew of a Caztek tower.

I contacted them to see if they are still in production, thank you.

 

[airforcetp1991]

Tony,

I have a pad/rail that I have built that lets me transport it in 6' sections. It has guy wires for support and I can raise the rocket with a winch. No one is around or under my rockets when I raise them. Beyone this, the details of what I do are not important.

One piece of advice I would offer is that I would never fly anything above an M motor on the equipment supplied at large launches. If I had the time, I could give you many examples where fliers regretted doing this. Balls in particular is a bring-it-yourself launch. Obviously, people have flown O motors from the supplied pads at Balls, but I would never even consider doing that. I want to know and control the characteristics of the pad in advance.

I'm not sure what an Attebery style is or a 1515 extrusion style of tower. If you are using a tower and not guides, then you will need to make or borrow the tower. The biggest issues I have seen with towers is a failure to secure the bottom of the tower, particularly if the motor exhaust can undercut the ground. Towers are often too short. When they are long enough, the guides sometimes are not strong enough to contain the rocket.

Jim

Agreed, the tower will have a steel base plate to avoid the exhaust undercutting it and my initial thoughts are an 8 foot tower. This is the Attebery tower, the newer ones have a steel base plate.

Tony

 

[airforcetp1991]

Wow - relegate that pad in the video to mid-power only.
Not even sure it's fit for that - you can see the wind blow it at the end.
That is insanely bad.

With a usual limit of 14" per side, flying out of the center of a triangular tower is for small-finned rockets only.

If I do end up making one my thought is to use a 12” square shape with 1515 aluminum.

 

[Siya]

Agreed, the tower will have a steel base plate to avoid the exhaust undercutting it and my initial thoughts are an 8 foot tower. This is the Attebery tower, the newer ones have a steel base plate.

Tony


View attachment 464615

Chris makes amazing launch towers too

 

[airforcetp1991]

Wow - relegate that pad in the video to mid-power only.
Not even sure it's fit for that - you can see the wind blow it at the end.
That is insanely bad.

With a usual limit of 14" per side, flying out of the center of a triangular tower is for small-finned rockets only.

For comparison this is a slightly larger motor on one of the same style rails... Still no excuse for my bad setup but this rail seems to do fine.


View attachment 20Feb2021.mp4

 

[JimJarvis50]

For comparison this is a slightly larger motor on one of the same style rails... Still no excuse for my bad setup but this rail seems to do fine.

At least the pad in this video has some legs for support. I don't see them in the first video. They could be there I suppose, but I don't see anything extending beyond the 70 sign.

One error in both videos is the use of an angled blast deflector. You can't use that with a high thrust motor unless the structure of the pad is strong enough to support the lateral force. Watch how that affected the exhaust and pad movement in your first video. I don't ever fly off of angled blast deflectors - they are for model rockets. I realize you didn't put them there, but you have to recognize these things. I think you narrowly avoided a very bad outcome.

Jim

 

[airforcetp1991]

At least the pad in this video has some legs for support. I don't see them in the first video. They could be there I suppose, but I don't see anything extending beyond the 70 sign.

One error in both videos is the use of an angled blast deflector. You can't use that with a high thrust motor unless the structure of the pad is strong enough to support the lateral force. Watch how that affected the exhaust and pad movement in your first video. I don't ever fly off of angled blast deflectors - they are for model rockets. I realize you didn't put them there, but you have to recognize these things. I think you narrowly avoided a very bad outcome.

Jim

Very good point, the pad in the first video has a base structure but it is not nearly as "wide" as the pad in the second video. I don't disagree that it was a close call, and I understand I was lucky to not have had a worse outcome. As I think back to the launch before this past weekend (but after the second video) the motor I used was about half the average thrust. That was on a similar rail with the smaller base and angled deflector but likely was not strong enough to cause the same issue.

Tony

 

[FredA]

Angled blast plate NOT Attached right at the base is wrong in SO many ways.
In that second video, the plate is mounted up the rail, away from the base.
This give a giant arm to torque the rail when the motor lights, bending the rail.

REMEMBER: at T=0, the blast plate takes the full takeoff thrust of the motor.

 

[rfjustin]

Caztek Engineering makes incredible launch towers. The current O3400 record rocket flew of a Caztek tower.

Impressive!

Link? Cost? Any other info?

 

[JoePfeiffer]

I wish I'd noticed that, and taken a look at the pad and rail after the fact. Those pads have been used without incident for rockets and motors in that size class for many years without incident...

It doesn't have a wide base, but its base is a truck tire filled with concrete.