Rocket 2 XXL, HPR lvl 1 cert rocket

[Voyhager3]

Update: altimeter secured!
It’s a perfectflite MAWD, and I also got the usb cable! So I’m exited about that

 

[Voyhager3]

I flew it again today on a g74, it went better as I got a “new” nose cone as Doc and I were talking and we thought that it would still be fine without my nose weight, so he let me take the 5:1 4” that has been sitting in the lost and found for a while and I used that. It was stable and I even stuck the landing!

I also got some goodies, and some BP so that’s good!

 

[Voyhager3]

Looks like we our chance at a late April launch has very quickly faded away, but we may have an April 8-9 launch, and Ken might be able to come down for it, but idk. So I might get to do a shakedown run on a G80 with the altimeter, but we shall see…
But I’ll be going down do Dalzell on may for my L1 (and maybe L2)!

 

[Voyhager3]

I finally decided on the payload section length of 20” so it’s now stands about 6’5”. This config. pictured is using the 5:1 nc I got, but I have the heavier 4:1 for the level 2 and lower altitude flights on H motors. I also have a shorter payload section so that I can just run an apogee deployment from my altimeter. But I can still fly it on those g74s without the ebay.
I plan to ground test in a few days, and paint after. But the new stuff will be black

 

[Voyhager3]

As some of you may have seen I did some ground tests, and I settled on 2 grams for both (may change after real world testing), and I'll hopefully paint it over the next few days.

And I might head down to Dalzell to just meet everyone down there, and fly some of my other MP/LP stuff since out LP (well small LP) season has more or less ended up at ROCC. And I've never been to a research launch so that will be fun. I'll also bring R2 XXL as I hope to get some in-person feedback on R2 XXL just to make sure it'll be fin for a L2 (I'm pretty sure that it'll be fine for the L1). I will probably tour the UofSC campus as I already got in, and as I have a statistically insignificant chance of getting into NC state (waitlisted), I want to have as many options open between UTK, Iowa state (will be there on the 7/8th), and UofSC.
I guess it'll be red glare weekend so it'll be probably a slower launch, but I'll see/ask @cwbullet if I see him around the forum, or any other members.

 

[Voyhager3]

I'm starting too second guess my L2, and I think i'll just buy more H and I motors and casings. But i'll still do my L1 in a few weeks, so I should let Ken know that I no-longer need that J270.
But I have big plans for this project still

 

[Hobie1dog]

I'm starting too second guess my L2, and I think i'll just buy more H and I motors and casings. But i'll still do my L1 in a few weeks, so I should let Ken know that I no-longer need that J270.
But I have big plans for this project still

Go ahead and get the J270, build that L2 rocket, use motor ejection, simple, it's done everywhere, most weekends, keep progressing at least to the L2 level. Come down to Dalzell on the 6th.

 

[Voyhager3]

Go ahead and get the J270, build that L2 rocket, use motor ejection, simple, it's done everywhere, most weekends, keep progressing at least to the L2 level. Come down to Dalzell on the 6th.

I already let Ken know I didn’t need the 270, but I’m still coming down on the 6th for my L1. (So save me a spot)

But I now plan to do my L2 next summer, or next year during college as the rocketry team there often helps members get their L2.

But I got big plans for that of possible, which may or may not entail a rather large 5.5” glassed monster that can an L motor. But I plan to get my L3 and let’s call it an L10, aka Masters in aerospace engineering. So I got big plans

 

[Voyhager3]

Update:
got motors a new casing(s)


Been trying to optimize some stuff to gain more altitude. Which means lightening it, as I can’t change the other variables, i.e. drag, atmospheric conditions, gravity, and total thrust*. But I can do things like using the lighter nose, I’m also going to rub without the eBay for the cert, because my RDDT showed up. So I got my ultra light coupler from Ken, and I’ll finish it up (not including painting) by Sunday.

 

[Voyhager3]

Done all sorts of things, lightened by 1kg, to gain about 500 feet alt.
Also got more reasonable quicklinks, 1/8 steel, 300lb working. Much more sensible

 

[Voyhager3]

Uh
So I guess I didn’t pass.

 

[Voyhager3]

Preliminary damage report:
Cause of incident, failure of LOC 29-38mm motor adapter, where the internal structure that held the motor split from the 38mm coupler/outer tube, causing the motor to exit through the top of the vehicle.
See internal structure above.

Damage noted at this time:
Motor adapter destroyed. Upper coupler destroyed. Motor mount, appears to be heavily damaged, further examination required. Parachute protector, ripped, but re-sewable. Parachute, one pencil sized burn hole, one small cluster of pin sized burn holes surrounding hole mentioned before. And a few small pin holes scattered, chute was saved, and more or less undamaged. Airframe, appears to be not structurally damaged, further examination required. ~1 foot of Kevlar shock cord needs to be removed. Motor case not damaged.


Upper coupler, pictured above


View from MMT pictured above.

Injures:
none

Estimated repair cost at this time:
$40

Plan:
Add new upper coupler, permanently downsize to 29mm MMT. Continue tear-down, to further gauge damage.

Thank you to @cichlidgoob for making sure the motor didn’t blow up, and everyone else at the ROSCO launch who helped with diagnosis of problem, and stuff.

 

[cichlidgoob]

Plan:
Add new upper coupler, permanently downsize to 29mm MMT.

That was a great report, and I wish you well on the next flight.

I would like to encourage you to go with a 38mm motor mount because a rocket that size would really benefit from it. There are many adapters that work perfectly fine, including Loc adapters, which I use all the time. I understand you had a bad experience this time but don’t let that turn you off of using adapters. They are a fantastic way to have a flexible rocket system, especially since you already have multiple nose cones for dialing in stability, an ebay for dual deploy and extra body tube sections to extend the length - I PROMISE you will wish you had a 38mm mount sometime in the future.

 

[Voyhager3]

That was a great report, and I wish you well on the next flight.

I would like to encourage you to go with a 38mm motor mount because a rocket that size would really benefit from it. There are many adapters that work perfectly fine, including Loc adapters, which I use all the time. I understand you had a bad experience this time but don’t let that turn you off of using adapters. They are a fantastic way to have a flexible rocket system, especially since you already have multiple nose cones for dialing in stability, an ebay for dual deploy and extra body tube sections to extend the length - I PROMISE you will wish you had a 38mm mount sometime in the future.

You’re probably right, I think you said the aero pack ones were good. So I think I’ll pick one up. My only concern was the damage to the MMT, but as you and others said, it would probably be fine if the mmt had a hole in it.
Especially because now that I think of it, the charred insides may make a poor bonding surface.

Hopefully next time will go better! Still shooting for the 10th!

 

[Buster]

I also recommend that you go with a 38mm as you can use it for both L1 38/240 and L2 38/720

 

[tsmith1315]

You’re probably right, I think you said the aero pack ones were good

I’ve only used LOC adapters, they work fine. I have some that are nearly 30 years old & wouldn’t hesitate to use them.

What I don’t see in your pics is a heavy fillet on the adapter’s centering rings. I’d have 1/4”+ of epoxy on the forward side of both rings. Once glued into the external tube, fill in the remaining space between the tubes, fore and aft, with epoxy. Not much of a weight penalty compared to the overall weight of the adapter.

Never had one fail.

 

[Voyhager3]

It’s worse than I thought

 

[Voyhager3]

Pulled the guts out.
Good news: all the damage is isolated between the middle CR and the upper CR, and the MMT between the lower CR and middle CR is (mostly) in perfect shape!

 

[cwbullet]

It was a spectacular flight regardless of the end results.



Yes, the motor will fly, albiet a little unstable, without the rocket.

 

[Voyhager3]

Clean the insides a bit, and then did some ground testing. I used a 1.5g charge in the (remaining) motor tube, just make sure the air frame would still be able to A: take the pressure, and B: Make sure the charge would be enough to pop the nose off. And everything worked perfectly!

So all I have to so is buy a new adapter, and stuff.

My only concern is something is falling into the opening in the CR and getting caught behind the top centering ring, but I think it'll be fine, because it's not large enough for the chute to fall in. So I don't think it'll be a problem.

 

[Voyhager3]

Did some more work and inspection today, and I got good, mildly inconvenient, moderately questionable, and bad news:
The good;
Removed the broken motor retainer bolt system. But there is still one remaining, which Mike said would be fine.
Mildly inconvenient news;
The upper tube coupler didn’t get glued well, so I have to reglue i.

Moderately Questionable news;
A very small fillet crack, don’t know if it came from the last incident or not, but I think it was. It’s not very long, and doesn’t seem to be deep.
Now the bad;
That same fin that had the fillet crack has a much larger and scarier “crack”. The plywood fin has started to de-laminate.

And suggestion on how to repair the fin? Because my thought would be to just pour some wood glue down and clamp it back together.

 

[Voyhager3]

Fin repair

 

[Simon_betts10]

This is why we make test pieces!View attachment 561188
Fin tab was too short

I seem to have this same issue way more than I care to admit.

 

[Simon_betts10]

Great post

 

[Voyhager3]

Man I keep forgetting to post here.
On June 10 I did my L1 and passed!!
Here are the pictures!
(Thank you Ron C. For the in flight photos!)
Also, I just secured a J350 for my L2 on the 8th, so I guess I am going for my L2!! Thank you Tom!!!!!

 

[Voyhager3]

Here’s a clip from Tom’s video of my flight:
https://youtube.com/clip/Ugkx6Rt8Ie4QH2gFwBnMleKw3vWoXGOEarAd

 

[T-Rex]

Good job!

Only change I would suggest is move the attachment point of the parachute closer to the nosecone. General consensus is the chute should be attached about 1/3 the shock cord length down from the nose (2/3 above the main portion of the rocket. this helps to ensure the parachute gets pulled out, while ensuring the nose cone doesn't slam into the rest of the rocket.

At the same time, I can understand that you might not want to change anything as it worked the last time.

Again, Good job on the L1 flight!!

 

[bad_idea]

Only change I would suggest is move the attachment point of the parachute closer to the nosecone. General consensus is the chute should be attached about 1/3 the shock cord length down from the nose (2/3 above the main portion of the rocket. this helps to ensure the parachute gets pulled out, while ensuring the nose cone doesn't slam into the rest of the rocket.

Agreed about changing the attachment point, but I do the reverse and put the fin section closer to the chute than the nose. When the chute deploys, the forward section will eject forward of the parachute until it hits the end of its cord. The rear section will continue to fly past the parachute until it hits the end of its own cord. If the nose stops relative to the chute before the fin section does, you risk a collision that's impossible if the fin section stops before the nose does (assuming the shock cord isn't especially elastic).

For very small, light cones, I do sometimes put them close to the chute (usually very close in that case), but for heavier cones or payload sections or forward bodies in a drogue deployment, I give the forward section the longer cord. Under drogue it's of course always possible the fin section will fly in and hit something, but that's probably with a little less violence than a full speed fin can smashing into a nose that just slowed dramatically (and also probably a sign it's time to try a slightly larger drogue).

Of course legions of people have had success doing the way you mention, so I mention the above method only as an alternative that has some advantages, and certainly not as the only way to do things. There are usually a half-dozen ways to do anything in rocketry, and nearly all of them work so long as they're done well.

 

[Voyhager3]

Good job!

Only change I would suggest is move the attachment point of the parachute closer to the nosecone. General consensus is the chute should be attached about 1/3 the shock cord length down from the nose (2/3 above the main portion of the rocket. this helps to ensure the parachute gets pulled out, while ensuring the nose cone doesn't slam into the rest of the rocket.

At the same time, I can understand that you might not want to change anything as it worked the last time.

Again, Good job on the L1 flight!!

Agreed about changing the attachment point, but I do the reverse and put the fin section closer to the chute than the nose. When the chute deploys, the forward section will eject forward of the parachute until it hits the end of its cord. The rear section will continue to fly past the parachute until it hits the end of its own cord. If the nose stops relative to the chute before the fin section does, you risk a collision that's impossible if the fin section stops before the nose does (assuming the shock cord isn't especially elastic).

For very small, light cones, I do sometimes put them close to the chute (usually very close in that case), but for heavier cones or payload sections or forward bodies in a drogue deployment, I give the forward section the longer cord. Under drogue it's of course always possible the fin section will fly in and hit something, but that's probably with a little less violence than a full speed fin can smashing into a nose that just slowed dramatically (and also probably a sign it's time to try a slightly larger drogue).

Of course legions of people have had success doing the way you mention, so I mention the above method only as an alternative that has some advantages, and certainly not as the only way to do things. There are usually a half-dozen ways to do anything in rocketry, and nearly all of them work so long as they're done well.

I agree with you both, and the first thing I did when I got home that night was actually moving the attachment point much closer to the NC/Payload. That mainly happened by accident/very tired me the night before didn’t catch that when I was tying up the cords and stuff.

But what I might do it love it back towards the fin can, just because “in theory” if the payload section lands first, the chutes load will decrease, thus the fin can’s speed will also decrease. And for the hard clay soil we have, that might be better, as my ply fin like to split on landings here for some reason.

 

[Voyhager3]