Astrobee-D Deployment fail!

Hi guys,

Today I went to my AARG club launch, and I took my Astrobee-D with me. Here's the video -

[video=youtube;EaLoZAt7xQM]https://www.youtube.com/watch?v=EaLoZAt7xQM&feature=youtu.be[/video]

It was a really windy day, perhaps 25-30MPH. Thankfully the G80-T brought the rocket up quick since the launch pad was very unstable.
Unfortunately, the parachute did not deploy. One of the people at the launch said it could be in part by not having enough weight on the nosecone to pull the parachute out. As it spiked to the ground, I checked and sure enough the parachute did not leave the rocket. The ejection charge has burned.




Any idea on how the parachute didn't come out? I am almost certain the two body tubes of the rockets separated.

Ouch! Sorry to see that, I have no input currently on what may have happened. This was a single chute rocket or iirc per another discussion I thought it had 2 chutes?

Yes it has 2 chutes.

From my years of experience there normally two non-deployment reasons for the chute not coming out.

1. Chutes stuck or jammed in the body tube. Not packed correctly. The chutes should slide in without any resistance.
2. Ejection charge does not go off, or, does not have enough pressure to eject the laundry.

From looking at the video I would say that #2 was the cause. Always do a puff test. Also check the distance between the NC and where you have attached the chute. I like mine about 8 inches below the NC.

I can not tell from the video if you had separation of the body tubes inflight or at ground impact.

The chute did slide very very easily, and it was very loosely packed.

There is burned black powder, and the ejection charge did go off, from the photos. It may have not had enough power to pop eject the chute.

Bill,

Ouch!!

Sorry for your loss. The Astrobee is a beautiful rocket and it looks like yours was painstakingly constructed.

I am just finishing up my Astrobee and this makes me nervous.

I have an Aerotech Arcas that I have successfully flown and this too, has a split fuselage but only 1 chute.

I am a bit leary of the Aerotech baffling system for the reason of too much restriction so I modded both rockets, eliminating the stock baffle and subbing a BT 80 baffle about 2 inches north of the end of the motor tube.

Here is my Arcas build thread : https://www.rocketryforum.com/showthread.php?66278-Aerotech-HV-Arcas

I am hoping that this will work well on the Aerobee.

Your disaster makes me want to ground test mine before I launch it.

How about some input from the forum braintrust on this.

Cheers!!

This is a somewhat unique rocket in that it comes down in two parts, each with their own chute. As a result, it can be a little tricky. It was my first mid power rocket so many years ago. I lost two of them to failure to deploy. On the third one, I went a different route and built it as a standard dual deploy with the halves tethered together.

When built as intended, it is very important to pack the chute for the upper section into the lower section first. Then pack the chute for the lower section on top of it. This will cause the chute for the upper section to "pull out" the chute for the lower section. If the rockets separate, weight should not be a problem for pulling out the chutes since the separation point is the mid-point of the rocket.

I know my solutions are just my own and that they come after the fact, but if you rebuild it you may want to learn from my experience as well.

Cheers,
Michael

Certainly could have been a weak ejection charge, based on the details you have posted.

iqsy59 said:

This is a somewhat unique rocket in that it comes down in two parts, each with their own chute. As a result, it can be a little tricky. It was my first mid power rocket so many years ago. I lost two of them to failure to deploy. On the third one, I went a different route and built it as a standard dual deploy with the halves tethered together.

When built as intended, it is very important to pack the chute for the upper section into the lower section first. Then pack the chute for the lower section on top of it. This will cause the chute for the upper section to "pull out" the chute for the lower section. If the rockets separate, weight should not be a problem for pulling out the chutes since the separation point is the mid-point of the rocket.

I know my solutions are just my own and that they come after the fact, but if you rebuild it you may want to learn from my experience as well.

Cheers,
Michael

Click to expand...

Bill,

Did both halves come in ballistic?

I am curious if both chutes did not deploy?

Thanks for your imput -

While I'm still not exactly sure what caused the failure to deploy, I will be taking your word for my next build. I don't exactly want to make another one, since I put too much sweat, time, and money into it, and partly since I'm recovering from the trauma of this utterly tragic launch.

marwady said:

Bill,

Ouch!!

Sorry for your loss. The Astrobee is a beautiful rocket and it looks like yours was painstakingly constructed.


I am just finishing up my Astrobee and this makes me nervous.

I have an Aerotech Arcas that I have successfully flown and this too, has a split fuselage but only 1 chute.


I am a bit leary of the Aerotech baffling system for the reason of too much restriction so I modded both rockets, eliminating the stock baffle and subbing a BT 80 baffle about 2 inches north of the end of the motor tube.

Here is my Arcas build thread : https://www.rocketryforum.com/showthread.php?66278-Aerotech-HV-Arcas

Your disaster makes me want to ground test mine before I launch it.


How about some input from the forum braintrust on this.

Cheers!!

Click to expand...

Thanks for the therapy marwady -

Nice Arcas! Smart move to do that with your Astrobee

My prayers that all goes well, if it doesn't let's organize a boycott against Aerotech.

Sorry to hear about you rocket. Looks like a great build. Thanks for posting so we can learn with you.

No problem, knowledge is power.

As I recall I the coupler on mine was way too tight and I had to peel two layers of paper off it. You should be able to hold it by the nose and it should stay in position and then separate when shaken. As mentioned above the order you pack the chutes is important.

When I built mine in 2002, it was my first "big" rocket. Having seen 2 others fail, I decided to do mine a bit different.

I nixed the stretchy shock cord & went with tubular nylon. [15ft]
Used both chutes on same cord, [tied on 4ft apart] and flew it with single break. Payload tied on just 2ft from end of cord.

Cut the coupler in half....cut 2in. off fin can airframe. Glued each 1/2 of coupler in 2in section and made av-bay.
Held bay in payload with 2 plastic rivets.

My original intent was just fly it with altimeter to do ejection & I could size my charge.It would fly like this:

At apogee, it would separate by altimeter at payload/fincan joint. [single deploy only] payload would fly off pulling both chutes out & land gently back on ground.



FIRST flight and I stuck the landing! Unfortunately the ground was soggy and one fin was planted firmly in the dirt. Gust of wind blew rocket over, breaking off fin tip substantially.
It flew only primed......so to repair I just cut off all the fins, added some epoxy fillets, and painted it for visibility, to aid in finding.
No longer a scale kit, I just enjoyed flying it. Other wise the fin can was stock, only thing I would do different is leave off the motor hook. It flies great on G's & H's as is. Eventually I went ahead & began flying it dual deploy, since it already had an av-bay.....my first DD rocket.
The mods were quite simple & I would say just get another one and have fun. We all have to make offerings to the rocket godz every now and then, unfortunately.........it was your turn.

iqsy59 said:

When built as intended, it is very important to pack the chute for the upper section into the lower section first. Then pack the chute for the lower section on top of it. This will cause the chute for the upper section to "pull out" the chute for the lower section. If the rockets separate, weight should not be a problem for pulling out the chutes since the separation point is the mid-point of the rocket.

Click to expand...

I wrote the instructions for the original AeroTech kits.

It is very important to follow proper parachute packing with the Astrobee-D and Mirage kits.
Pack the upper section parachute first then put in the booster parachute. Unlike model rockets which use wadding that pushes the parachute(s) out, the ejection gasses pass out of the baffle, around the parachute(s) and blows off the nose cone/upper section. The nose cone/payload section must separate with enough energy to pull out the parachutes.

Initiator001 said:

I wrote the instructions for the original AeroTech kits.

It is very important to follow proper parachute packing with the Astrobee-D and Mirage kits.
Pack the upper section parachute first then put in the booster parachute. Unlike model rockets which use wadding that pushes the parachute(s) out, the ejection gasses pass out of the baffle, around the parachute(s) and blows off the nose cone/upper section. The nose cone/payload section must separate with enough energy to pull out the parachutes.

Click to expand...

Hopefully, I didn't misrepresent anything from the instructions, Bob. This is absolutely one of my very favorite kits ever. I learned so much about rocketry and moving up in power from my first one. I aced my Senior Design project with my second one. It was an event-based altimeter based on the old PIC micromprcessor. I considered that quite an accomplishment in the mid-90's! My third (and current) D is where I started to learn more about modding. I built it to fly on long-burning H's....which it does...perfectly! It has as many flights on it as any rocket in my fleet. And I have a fourth one stashed away for future plans.

To the O.P., I hope that you rebuild it or replace yours. The Astrobee D always gets a lot of attention on the field. It should. It is a great rocket!

Cheers,
Michael

Initiator001 said:

I wrote the instructions for the original AeroTech kits.

It is very important to follow proper parachute packing with the Astrobee-D and Mirage kits.
Pack the upper section parachute first then put in the booster parachute. Unlike model rockets which use wadding that pushes the parachute(s) out, the ejection gasses pass out of the baffle, around the parachute(s) and blows off the nose cone/upper section. The nose cone/payload section must separate with enough energy to pull out the parachutes.

Click to expand...

The problem is that that the ejection charge didn't have enough power to pop the upper payload section off, and many other people have the same problem. I followed all directions as instructed, and did not use wadding, and the sections still didn't deploy. The instructions tell you to put the bulkhead/payload bay 3 inches inside the upper body tube, however it won't even fit, so instead I sanded 3 inches of the bulkhead down until it is a snug fit. Apparently the snug fit isn't loose enough, because it didn't separate! If we sand it down too much, the rocket will separate in mid air before reaching it's potential apogee, since it's so loose. I feel like I'm going around in circles here, the kit is pretty old so Aerotech can't do anything, and the only option for us is to mod the rocket.

[video=youtube;KGQET9Op3x8]https://www.youtube.com/watch?v=KGQET9Op3x8&feature=youtu.be[/video]

I've slowed down footage, and as you can see it all crashes in one piece.

Now I am a little confused, Bill. I am only trying to understand the conditions so that we can all contribute to preventing possible future failures.

I am fairly sure that the coupler should be glued into the upper payload section so that it slides into the booster. From your description, it sounds like it was not glued into the upper. There was a bulkhead in the coupler, correct? If not, then the SU engine may well not have had enough powder to pressurize the volume of the full rocket, given the weight of the payload section. Would you be interested in sharing a photo of the coupler joint to the rocket?

Cheers,
Michael

I've thrown the rocket out, so I can't get any photos, but the coupler tube was glued half way in the upper body tube. A bulkhead plate was attached to the top of the coupler tube, and a ring eye bolt held the shock cord and parachute in place.

RocketryBill said:

I've thrown the rocket out, so I can't get any photos, but the coupler tube was glued half way in the upper body tube. A bulkhead plate was attached to the top of the coupler tube, and a ring eye bolt held the shock cord and parachute in place.

Click to expand...

Exactly like the instructions tell you to do.

One other thought. I assume you stretched and fluffed up the steel mesh for the stock baffle, like the instructions mention?
Not doing so might have caused the problem, but it sounds like you followed the instructions carefully.

I am still leaning towards a weak ejection charge. Happens once in a fairly great while.

I stretched and fluffed that mesh until 6 inches long. Just like the instructions.

Man so sorry for your loss. What a nice vehicle. If I am reading this right and you have the baffle system ( I have a thread on here about it) I was leary of it. But it preformed perfectly. In fact so well I even added three handfuls of dog barf to cushion the charge. One thing I noticed my charge caps were melted into almost nothing just a sliver when i dumped them out. In the pictures you posted is that the red cap that is covering the charge? If it is then I'd say it was the charge itself. And that engine manufacturer owes you a rocket.

The gas baffle is completely intact, and there is absolutely no damage in the coil. Just a little browning, that I washed away with water and isopropyl rubbing alcohol. By now, I can tell many have had this same issue and it isn't just me. I will be contacting Aerotech on this problem, and will let them know how much of a gamble it is to launch one of their rockets. They for sure owe me a rocket.

RocketryBill said:

The gas baffle is completely intact, and there is absolutely no damage in the coil. Just a little browning, that I washed away with water and isopropyl rubbing alcohol. By now, I can tell many have had this same issue and it isn't just me. I will be contacting Aerotech on this problem, and will let them know how much of a gamble it is to launch one of their rockets. They for sure owe me a rocket.

Click to expand...

I have flown several of the AT 2.6" (and other manufacturers as well) diameter models a good number of times on single use AT motors with no issues. I have flown models with and without the AT mesh baffle system. The problem you had is not common, but it does show up once in a great while. The only AT no ejection failure on a single use motor that I have had since the mid 1990s was on a G40 a couple of years ago. This was in an old 4" diameter NCR Patriot and I must say the motor was pretty old. The charge went off but it did not separate.

I have an AT Astrobee D about half built and I will not hesitate to fly it on reasonably fresh AT single use motors. Will likely use one chute and take my chances on the scale details.

I would like to clarify, since I am one who reported losing a rocket. It was through my own inexperience rather than the design or manufacturing quality of the kit. I have lost rockets from every major manufacturer you can think of! I am only speaking of my own experience and not that of you or others. I have many Aerotech rockets and they are among the highest quality kits in my fleet. Believe me...I have a LOT of kits!

Sometimes we lose rockets. Sometimes we lose them on their maiden launch. Like CJ said...the rocket gods must receive their sacrifice from time to time. It is part of the thrill for me knowing that there is risk of losing it every time the button is pushed. (See my sig.) That is why I always try to have my rockets fully finished rather than naked before I fly them.

Good luck to you, and happy flights in the future!

Cheers,
Michael

There has to be a reason for this unjustified crash, and right now I've eliminated every possibility but a weak ejection charge, and that is a issue on behalf of the engine manufacture, which is a Aerotech motor. If you sanded down the coupler tube so it was a loose fit with the lower body tube, then there is still a possibility the rocket will prematurely separate and not have time to deploy it's parachute, and I am assuming the reason your Astrobee-D works is because there is a loose fit between both of the body tubes.

Bill

blackjack2564 said:

When I built mine in 2002, it was my first "big" rocket. Having seen 2 others fail, I decided to do mine a bit different.

I nixed the stretchy shock cord & went with tubular nylon. [15ft]
Used both chutes on same cord, [tied on 4ft apart] and flew it with single break. Payload tied on just 2ft from end of cord.

Cut the coupler in half....cut 2in. off fin can airframe. Glued each 1/2 of coupler in 2in section and made av-bay.
Held bay in payload with 2 plastic rivets.

My original intent was just fly it with altimeter to do ejection & I could size my charge.It would fly like this:

At apogee, it would separate by altimeter at payload/fincan joint. [single deploy only] payload would fly off pulling both chutes out & land gently back on ground.

FIRST flight and I stuck the landing! Unfortunately the ground was soggy and one fin was planted firmly in the dirt. Gust of wind blew rocket over, breaking off fin tip substantially.
It flew only primed......so to repair I just cut off all the fins, added some epoxy fillets, and painted it for visibility, to aid in finding.
No longer a scale kit, I just enjoyed flying it. Other wise the fin can was stock, only thing I would do different is leave off the motor hook. It flies great on G's & H's as is. Eventually I went ahead & began flying it dual deploy, since it already had an av-bay.....my first DD rocket.
The mods were quite simple & I would say just get another one and have fun. We all have to make offerings to the rocket godz every now and then, unfortunately.........it was your turn.

Click to expand...

I did something similar with an AT HV ARCAS. Only had to add a bulkhead to the coupler and turned her into a DD rocket. I epoxied small steel strips in the tubes to help shear the shearpins and save the tubes. I flew it exclusively on H-128's to
~ 1400' flights with the Adept 22 dealing with the dual deployment chores quite nicely. Tried a red H165 and I saw a "burble" in the tail on the ascent and thought, "Uh oh, flutter." One fin cracked at the root partially at the aft end. Perfectly repairable
and will be flown again.

Kurt

Flew on a G80? Any idea what black powder (BP) charge that ones has? I launch my Astrobee D using AT single use H135 adjusted down to 11 sec. delay. As I recall there is 1.5gr of BP in that one. I use all of it. The size of the Astrobee has a pretty good volume size so maybe the G80 needs some supplemental BP?