Featherweight Blue Raven Development Thread: Deployment logic

[kjhambrick]

Adrian --

I received my Blue Raven, AV-Bays and Charger yesterday afternoon.

They're beautiful -- you should be proud !

I immediately fired up Open Rocket to design a new vehicle for my new, improved Payload Package.

Today I'll be playing with my Samsung Phone and the App and the Blue Raven Flight Sim

Thank you very much for the quick turn-around, Adrian !

-- kjh

p.s. funny anecdote ... When I opened the package, the small orange box ( 29-mm AV-Bay ) 'clung' to the small green box ( 38-mm AV-Bay ) and I was thinking there must be tape residue on one-or-both small boxes. I looked and looked until I opened the orange box and 'found' the magnet

I do understand now why there is a 'Large Magnet' Option for the AV-Bays.

I imagine I'll be losing my magnets

Will any Magnet work to trigger the power switch ?

 

[Adrian A]

Adrian --

I received my Blue Raven, AV-Bays and Charger yesterday afternoon.

They're beautiful -- you should be proud !

I immediately fired up Open Rocket to design a new vehicle for my new, improved Payload Package.

Today I'll be playing with my Samsung Phone and the App and the Blue Raven Flight Sim

Thank you very much for the quick turn-around, Adrian !

-- kjh

p.s. funny anecdote ... When I opened the package, the small orange box ( 29-mm AV-Bay ) 'clung' to the small green box ( 38-mm AV-Bay ) and I was thinking there must be tape residue on one-or-both small boxes. I looked and looked until I opened the orange box and 'found' the magnet

I do understand now why there is a 'Large Magnet' Option for the AV-Bays.

I imagine I'll be losing my magnets

Will any Magnet work to trigger the power switch ?

Thanks for your support!

Any magnet will work, though stronger neodymium magnets will have longer range.

 

[kjhambrick]

Thanks for your support!

Any magnet will work, though stronger neodymium magnets will have longer range.

Good to know.

I'll be making a 'magnetic magic wand' for the reach and so I won't lose my magnets in my range box, on my work bench or at the launch site

Thanks again Adrian !

-- kjh

 

[user 41710]

Hi Adrian,

What is the best way to program the Blue Raven for an Airstart based on a timer from launch rather than a motor burnout?

Would you set the burnout count to be >0 like the screenshot below?

Thanks

 

[Adrian A]

Hi Adrian,

What is the best way to program the Blue Raven for an Airstart based on a timer from launch rather than a motor burnout?

Would you set the burnout count to be >0 like the screenshot below?

Thanks

I'm guessing you want to start the airstart while the first motor is still burning?

You would need to use the custom configuration. There you can set the burnout count threshold to be >= 0, or just turn off checking the burnout count by clicking on the "AND" to toggle it off. Then click on the "AND" next to Time since liftoff > to turn on that check instead.

BTW, thanks for your screenshot; I noticed a typo in the label text for the burnout check in the airstart function view, which should read ">=" rather than ">"

 

[user 41710]

Hey Adrian,

Actually wanting to do a standard Stage-Sep (first motor not still burning). Is a Motor burnout detect a better choice over a timer from launch that is based on the given motor burn time? I've heard that launch detect is more reliable than a burnout detect.

 

[Adrian A]

Hey Adrian,

Actually wanting to do a standard Stage-Sep (first motor not still burning). Is a Motor burnout detect a better choice over a timer from launch that is based on the given motor burn time? I've heard that launch detect is more reliable than a burnout detect.

The motor burnout is very reliable, basically the same as the launch detect because it uses the same sensor and similar logic. Once the rocket is going 40 feet/second or faster, the burnout detection looks for a drop in the velocity of 5 feet/second from the maximum velocity to that point.

Burnout detection provides some additional safety against an accidental ground start because the launch detection is triggered by 3 feet/second vs the burnout detection requiring 40 feet/second. And a timer doesn't add any protection at all. Definitely do also use a minimum baro altitude and the maximum tilt so that all available sensors have to be in agreement that the rocket is safely away and pointed upward. The Airstart function you can select takes care of all these checks.

 

[GAP]

@Adrian A I'm programming my Blue Raven tomorrow for a Mach 3 flight. Given the two recent cases of Blue Ravens firing charges on the pad I'm curious if you have any recommendations. Should I use the latest software and stick with the default deployment settings? If I turn the Blue Raven on and then off should I ensure the capacitor completely drains before powering back on?

Note: I've never flown this Blue Raven, but I did do the remote ejection charge testing with it which worked perfectly.

Thanks in advance!

 

[Adrian A]

GAP,

@Adrian A I'm programming my Blue Raven tomorrow for a Mach 3 flight. Given the two recent cases of Blue Ravens firing charges on the pad I'm curious if you have any recommendations. Should I use the latest software and stick with the default deployment settings? If I turn the Blue Raven on and then off should I ensure the capacitor completely drains before powering back on?

Note: I've never flown this Blue Raven, but I did do the remote ejection charge testing with it which worked perfectly.

Thanks in advance!

GAP, I think you know more about this than I do. I got an email last week from one user who had a charge fire on the pad on one of his two Blue Ravens on two launch attempts, and I replied with a bunch of follow-up questions to learn more about what happened. I have not received a reply from him. Was that you? If not, could you direct me to whatever information you have?

Until I learn more, I don't have much advice to provide. This hasn't happened in the year+ of flight testing I've done with the Blue Raven, and this is the first I have heard of this happening with a customer. Custom settings shouldn't make a difference because every output, custom or not, depends on launch detection before it would fire. Waiting to make sure the capacitor is discharged before powering up wouldn't hurt, but there are hardware and software features that make that unnecessary also.

 

[GAP]

GAP,


GAP, I think you know more about this than I do. I got an email last week from one user who had a charge fire on the pad on one of his two Blue Ravens on two launch attempts, and I replied with a bunch of follow-up questions to learn more about what happened. I have not received a reply from him. Was that you? If not, could you direct me to whatever information you have?

Until I learn more, I don't have much advice to provide. This hasn't happened in the year+ of flight testing I've done with the Blue Raven, and this is the first I have heard of this happening with a customer. Custom settings shouldn't make a difference because every output, custom or not, depends on launch detection before it would fire. Waiting to make sure the capacitor is discharged before powering up wouldn't hurt, but there are hardware and software features that make that unnecessary also.

I don't know that much about it and neither of them was me. One was Georgia Tech and another one was some individual two stage project. I know they were both using them as timers. Honestly I thought it was probably user error.

However, I just did charge testing again since I needed to change my shear pin configuration and had a charge fire when I opened the app ( a couple hours ago). I had originally opened the app to check continuity and didn't have any. I tried to ejection charge test anyways just to see if it would work and it did not. I rewired the charge and reopened the app and that's when it fired. Maybe it still thought I had pressed the button previously and was still in ejection charge mode? But if that was the case wouldn't it have fired as soon as I turned the altimeter back on after rewiring the charges?

It was on the latest firmware and the android app. More data to follow...

 

[Adrian A]

I don't know that much about it and neither of them was me. One was Georgia Tech and another one was some individual two stage project. I know they were both using them as timers. Honestly I thought it was probably user error.

However, I just did charge testing again since I needed to change my shear pin configuration and had a charge fire when I opened the app ( a couple hours ago). I had originally opened the app to check continuity and didn't have any. I tried to ejection charge test anyways just to see if it would work and it did not. I rewired the charge and reopened the app and that's when it fired. Maybe it still thought I had pressed the button previously and was still in ejection charge mode? But if that was the case wouldn't it have fired as soon as I turned the altimeter back on after rewiring the charges?

It was on the latest firmware and the android app. More data to follow...

Just to be clear, you tried an ejection charge test when there was no continuity, then powered off the Blue Raven and turned off the app, then connected the charge and powered the Blue Raven on and nothing happened, but then when you opened the app and connected, the charge fired? I'll see if I can reproduce this.

 

[GAP]

Just to be clear, you tried an ejection charge test when there was no continuity, then powered off the Blue Raven and turned off the app, then connected the charge and powered the Blue Raven on and nothing happened, but then when you opened the app and connected, the charge fired? I'll see if I can reproduce this.

Correct. I opened the app to ejection charge test, noticed there was no continuity, but tried to fire the charge anyways. That didn't work ( I waited for the test to end/ for the spinning dots to stop after the countdown, so I "closed" the app, but not fully. I'm not sure how to explain that, there is a difference between ending/terminating an app and simply going to another app with it open in the background. In this case the app was still open in the background as I powered off altimeter and fixed the wiring issue. I then nominally powered up the Blue Raven again and reopened the app from the background process and that's when it fired.

I'm also going to try and replicate this later tonight once it stops raining here.

I'm unsure if this is important, but I was comparing the .csv files from my nominal test a few days ago and the test today and noticed the test today only started recording data 0.2 seconds before firing the charge while the nominal test started recording 2 seconds before firing. Is this normal?


Normal test data from a few days ago:


Test from today below:

 

[Adrian A]

Correct. I opened the app to ejection charge test, noticed there was no continuity, but tried to fire the charge anyways. That didn't work ( I waited for the test to end/ for the spinning dots to stop after the countdown, so I "closed" the app, but not fully. I'm not sure how to explain that, there is a difference between ending/terminating an app and simply going to another app with it open in the background. In this case the app was still open in the background as I powered off altimeter and fixed the wiring issue. I then nominally powered up the Blue Raven again and reopened the app from the background process and that's when it fired.

I'm also going to try and replicate this later tonight once it stops raining here.

I'm unsure if this is important, but I was comparing the .csv files from my nominal test a few days ago and the test today and noticed the test today only started recording data 0.2 seconds before firing the charge while the nominal test started recording 2 seconds before firing. Is this normal?

Thanks so much for taking the time to provide these details. I wired up ematches to all the outputs and tried to repeat this myself using my Android phone, but so far no luck. I also have been doing a lot of power cycling with the charges connected, with different "off" times to see if I could get some misbehavior, and again, no charges fired. It sounds like though, at least in your case, the phone app sent a command to fire a charge when it shouldn't have, independent of the power cycling.

I'll keep trying different things....

 

[Adrian A]

I experimented with doing a ground test and then power cycling the Blue Raven before it got done downloading the data from the test. At one point I found that within the ground test screen, the app showed that downloading was in progress when the LED activity showed that it was not ongoing. Then I switched the ground test channel from Apo to Main, and the main channel fired. I captured the USB traffic when this happened, and there was a command from the phone to the Blue Raven when it fired. This suggests to me that there is apparently a problem in the phone app that can allow a ground test fire command to get queued up inappropriately and then sent later. The app stays connected with the Blue Raven even when it is in the background (when the user is using another app) My advice until we get this fixed is to either avoid the ground test function for now, or force-quit the app after ground testing is completed, before real charges are installed.

 

[GAP]

I experimented with doing a ground test and then power cycling the Blue Raven before it got done downloading the data from the test. At one point I found that within the ground test screen, the app showed that downloading was in progress when the LED activity showed that it was not ongoing. Then I switched the ground test channel from Apo to Main, and the main channel fired. I captured the USB traffic when this happened, and there was a command from the phone to the Blue Raven when it fired. This suggests to me that there is apparently a problem in the phone app that can allow a ground test fire command to get queued up inappropriately and then sent later. The app stays connected with the Blue Raven even when it is in the background (when the user is using another app) My advice until we get this fixed is to either avoid the ground test function for now, or force-quit the app after ground testing is completed, before real charges are installed.

Thanks for the update. I think that's probably what happened to me, because I was switching between apogee and main. And I'm pretty convinced the other instances of early deployment aren't related.

Do you think this could affect the Blue Raven when never using the ground test feature? My Blue Raven serial number is 0133 (I think) if that's important to you.

On another note I tried various power cycling of the raven myself and was not able to recreate the error (which is very reassuring), although I couldn't remember the exact steps I took previously, but it appears you were able to figure those out. I also used the simulation feature for my flight which worked perfectly.

Thanks again Adrian for taking the time to help me with this. Makes me feel a lot better about my flight in a week!

 

[patbunn]

I must be missing something. I have both a 29mm and a 38 mm ebay From Feather weight and two Blue Ravens that I hope to fly this weekend.

When both are assembled the into the ebay, is just 2" long which seems mighty short for use as a coupler on a minimum diameter rocket. Am I wrong about the short coupler?

What am I missing?

Thanks

Pat

 

[Adrian A]

I must be missing something. I have both a 29mm and a 38 mm ebay From Feather weight and two Blue Ravens that I hope to fly this weekend.

When both are assembled the into the ebay, is just 2" long which seems mighty short for use as a coupler on a minimum diameter rocket. Am I wrong about the short coupler?

What am I missing?

Thanks

Pat

If you glue in one end 0.5" deep (cylindrical glue joints are really strong even without much overlap), then you have 1.5" of exposed coupler left. IMO this is pretty ideal for a 29mm airframe. For 38mm airframe, it's adequate if you have a snug fit.

If you want to go longer, you can, but you'll need to add some spacers inside to hold the battery in place, and get some longer threaded rods from McMaster Carr or equivalent.

 

[kjhambrick]

I must be missing something. I have both a 29mm and a 38 mm ebay From Feather weight and two Blue Ravens that I hope to fly this weekend.

When both are assembled the into the ebay, is just 2" long which seems mighty short for use as a coupler on a minimum diameter rocket. Am I wrong about the short coupler?

What am I missing?

Thanks

Pat

@patbunn --

I am not an expert, in fact, I've got very little experience with the Blue Raven, but I too have the 29mm and 38mm Featherweight AV-Bays.

As you noted, they seem too short to use as-is and even more importantly, you'll want to isolate the fore and aft circular PC-bulkheads from your ejection charges.

Therefore, you'll need two additional short couplers with outboard passive bulkheads , one forward and one aft of the AV-Bay assembly in addition to the coupler that jackets the AV-Bay assembly.

Search for @Adrian A's Threads about the ejectable AV-Bay here on TRF to see what I mean.

If you check Adrian's posts, you'll see that the 2-inch Featherweight AV-Bay may require an additional section of coupler, fore and aft to isolate the two bulkheads from the ejection charge.

I am still trying to wrap my head around this new concept so for now, I've got a Power Perch for larger diameter rockets ( 54mm and up ) and I am about to launch a 1.325 inch glassed BT-55 rocket with an EDIT: Adaptive Additive Aerospace Simple Circuit, FW Mag Switch and Blue Raven on a 'traditional sled' which will fit in a 29mm diameter coupler.

Adrian does have a pair of 38mm passive bulkheads with 3-inch aluminum rods which is a nice kit in that it isolates the ejection charges outside the passive bulkheads. I own one but I am not ready to try it yet.

I am sure that other Blue Raven Fliers will post as will @Adrian A when he returns from his camping trip.

Good luck Pat and have fun at Airfest !

-- kjh

 

[patbunn]

I saw the instruction about glueing in the top of the coupler. If you glue the coupler in - How do you attach the charges for the main chute in the upper section?

I am still confused. If you permanently glue in the coupler - it seems you lose access to wiring on the glued in end? I guess you can have permanent wires wired to the non electronic end?

Pat Bunn

 

[Adrian A]

I saw the instruction about glueing in the top of the coupler. If you glue the coupler in - How do you attach the charges for the main chute in the upper section?

I am still confused. If you permanently glue in the coupler - it seems you lose access to wiring on the glued in end? I guess you can have permanent wires wired to the non electronic end?

Pat Bunn

The bulkheads are clamped around the ends of the coupler by the threaded rods, but they are not permanently installed. You can assemble all but the passive bulkhead together, attach the main chute charge, and then push that through the main chute tube. Then install the passive bulkhead and the apogee charge on the end of the coupler.

 

[patbunn]

The bulkheads are clamped around the ends of the coupler by the threaded rods, but they are not permanently installed. You can assemble all but the passive bulkhead together, attach the main chute charge, and then push that through the main chute tube. Then install the passive bulkhead and

So you are saying that the bulkheads should fit inside the coupler? Mine isn't close even with a paper coupler. They are the size of the OD of the coupler? When I put the system together it is the size of the original coupler with the bulkheads at the end, the same OD as the coupler. If I glue the coupler to the top of the rocket, there is no way I have any access to the top bulkhead?


Pat

 

[Adrian A]

So you are saying that the bulkheads should fit inside the coupler? Mine isn't close even with a paper coupler. They are the size of the OD of the coupler? When I put the system together it is the size of the original coupler with the bulkheads at the end, the same OD as the coupler. If I glue the coupler to the top of the rocket, there is no way I have any access to the top bulkhead?


Pat

You install the top bulkhead from the top of the tube and push it down the tube and into the coupler.

 

[patbunn]

You install the top bulkhead from the top of the tube and push it down the tube and into the coupler.

My top tube is 12 inches long. No way I can push the bulkhead down 12 inches to the coupler and and replace the screws.

Pat

 

[watheyak]

When I've done this, my coupler was glued into the forward (nosecone end) tube. Mine was around 12" as well. The nuts, allthread, charge and shock cord are all attached to the forward, passive bulkhead. That is pushed down into the forward tube and seats against the top of the glued in coupler like a traditional av-bay plate. I used a dowel or something to push it all the way down there.

Once there, I installed the bulkead with the battery and Raven on it onto the protruding allthreads, tightened down the nuts with the charge leads underneath, and attached the harness.

My coupler was 4" long but I used longer allthread and an alternate means of battery retention. (Electrical tape. Fancy).

I wish I had pics but it's been many years.

 

[Adrian A]

My top tube is 12 inches long. No way I can push the bulkhead down 12 inches to the coupler and and replace the screws.

Pat

The threaded rods are attached to the forward bulkhead, along with the charges and Blue Raven, and that assembly is just pushed down the tube until the threaded rods extend past the open end of the coupler. The only fasteners that are touched at that point are the nuts clamping the second bulkhead to the exposed end of the coupler using the threaded rods.

 

[kjhambrick]

Wow !

Thanks for that explanation, Adrian.

I finally 'see' it now.

-- kjh

 

[patbunn]

I think I understand now. Here are some photos of my installation. Does it all look OK?

Thanks for staying with me

 

[kjhambrick]

Thank you for asking the questions @patbunn.

I really do have an idea now how to apply the 38mm and 29mm Featherweight AV-Bays in a 'classic' dual deployment rocket now !

-- kjh

 

[Adrian A]

I think I understand now. Here are some photos of my installation. Does View attachment 601431it all look OK?

View attachment 601429View attachment 601430Thanks for staying with me

Yes, that looks fine.

 

[Burner]

Very impressed with the Blue Raven thus far, but had a question regarding disarming channels and flight readiness. If I were to power up the Blue Raven with my avionics bay open and immediately disarm all my pyro channels, then finish a few preparations and close up my avionics bay before rearming on the pad, does the live data give any indication there was some event that would cause any issues proceeding with a flight?

For example, I powered up the BR and disarmed the apogee channel that had an ematch connected. While the BR was beeping indicating it was ready for flight, I swung it enough that it thought there was a launch event and the beeping stopped. I then rearmed the apogee channel and it was showing green because it had continuity, but the altimeter was not beeping. Is there any indication on the live data stating it shouldn't be flown in the event i cant hear beeping?