Vogon Poetry - 2 stage - old thread

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Slowly working on it..
still working on the AV bays when I can catch time between juggling kids, both mine and extras....

I also got the Peregrine CO2 system installed on the bottom bulkhead of the sustainer.


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You chopped up my centering rings! Oh well.

Are you going to route the antenna through a drilled or routed hole in the centering rings? Also, how're you ensuring the tracker doesn't fall free when the interstage coupler is ejected from the booster upon parachute deployment?
 
If you look at the picture with the green fiberglass 4" bulkhead, you can just about see that I have sunk four 8-32 threaded inserts into the centering rings. The fiberglass bulkhead will have screws going through to secure. The tracker will be inside the bottom of the interstage coupler with an RRC3. The screw switches will be installed onto the chopped rings.

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Tomorrow is propellant mixing. Pete says that he has to replace two N's for another project - BALLS peeps... the two stage Kegerator should fly this year!!!
we also are planning to cast enough to fill a couple of 6000 cases and a couple of 7600's That would mean that the loads for Vogon Poetry, in 3" to 3" hardware, would be roughtly a full M to a 20% M.. not too mad
 
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OK, guess it was an earlier discussion that had the tracker mounted there...

I'll go back to eating popcorn.
 
I see youve put a lot of thught into the structural integrity of the IST itself, good, but what about the coupler holding it into the booster airframe, and the length of motor youre using on your sustainer into it? We've seen quite a few full stack (with full weight) tests prove that even a thrust tilt or cone isnt usually an issue when you have atleast 2 calibers of motor hanging out of the sustainer... but imagine holding a broomstick in your hand by just the very end... If you have a long heavy sustainer being balanced into that IST by a mere 6" , theres a high chance that it will tear right out of your IST if your rocket takes a turn or a heavy tilt under thrust. Seen it happen before. The same issue lies when you have less than sufficient coupler of the IST into the booster airframe. Rocket takes a tilt and the whole top half snaps right off.

But again... we've seen tests proving it works as well. Hard to say how solid it is or if theyre all just getting lucky.

Nice to see the telemega being used for staging since it has the capability to do off vertical staging inhibition. I believe they finally made this a requirement for installed impulse greater than a K, which shouldve been the case years prior if you ask me but...

Consider CSI RF tracking on that sustainer. works well out on the playa. N to M that puppy is gonna go high. Dont put all your eggs in one tracking basket. Good luck! Hope those highly swept fins dont flutter! Theyre aluminum so... you'll probably be okay there.
 
The coupler is a 3" body tube that goes through the whole of the IST (spot the pun?). The pic of the bottom of the sustainer shows that the bottom of the motor will go 3.75" into the top of the inter-stage. I was aiming at around 4.5, but, things started to get a little weird moving the fins that far forward.

I have done a couple of two stagers before, but nothing of this size. Also this is my first build for Team Numb. Pete has been quite happy to sit back and watch, and comment (although not on here). Also a reason why I did this as a build thread. I am immensely grateful for all the input I have been receiving, and have seriously been looking into everything that has been said.
I am not overly worried about the fins. Trying to keep this under Mach 2 for the first few flights. Then we want to go for altitude and max speed being two separate flights. When it comes down to max speed, yeah, we may kill the rocket, but, the Vogon will have a glorious death!
 
Nice to see the telemega being used for staging since it has the capability to do off vertical staging inhibition.
I think this only works if the rocket is not rotating very quickly. Fast rotation saturates the gyros IIRC. Worth checking out if this is your intent.
 
I see youve put a lot of thught into the structural integrity of the IST itself, good, but what about the coupler holding it into the booster airframe, and the length of motor youre using on your sustainer into it? We've seen quite a few full stack (with full weight) tests prove that even a thrust tilt or cone isnt usually an issue when you have atleast 2 calibers of motor hanging out of the sustainer... but imagine holding a broomstick in your hand by just the very end... If you have a long heavy sustainer being balanced into that IST by a mere 6" , theres a high chance that it will tear right out of your IST if your rocket takes a turn or a heavy tilt under thrust. Seen it happen before. The same issue lies when you have less than sufficient coupler of the IST into the booster airframe. Rocket takes a tilt and the whole top half snaps right off.

But again... we've seen tests proving it works as well. Hard to say how solid it is or if theyre all just getting lucky.

The "wobble factor" has been a concern over the whole of the interstage design and build. I wanted the puppy to be SOLID, which is why I went with a solid wood approach. At this point I wouldn't be suprised if the aluminium motor case was the weaker point.

Nice to see the telemega being used for staging since it has the capability to do off vertical staging inhibition. I believe they finally made this a requirement for installed impulse greater than a K, which should've been the case years prior if you ask me but...

Consider CSI RF tracking on that sustainer. works well out on the playa. N to M that puppy is gonna go high. Dont put all your eggs in one tracking basket. Good luck! Hope those highly swept fins don't flutter! They're aluminum so... you'll probably be okay there.

TeleMega - Yes.
A few of years ago, I was starting to play with staging and clusters. I had a four inch Kraken with a cluster of four 38mm motors. Note tense. Had.
I had loaded it with a pair of skids on the pad, to a pair of smokies, 2 seconds after first motor cutout.
One skid lighted on the pad... the rocket went up, then started to tilt. Just as the rocket reached horizontal, the second skid lit. Awesome the amount of 'wing' area that the Kraken has. The rocket rolled so that the skid was 'under' the rest and kept happily going horizontal. Just now the Raven realized that the first skid has finished burn, and lit the two smokies to help with the second skid. This looked awesome.
Of course, when the smokies had quit, the altimeter looked at barometric altitude. Trouble is that, when the smokies quit, so did the slightly upward cant of the nose. As soon as the nose dropped, the altimeter said "APOGEE" and fired!
Bluetube doesn't zipper, it unwinds, quite awesomely.

On my walk of shame back to camp, I passed Keith and B'dale. I looked over and said something like "seems I need to visit you for a purchase soon". B'dale just 'yup'ed.

The staging and clustering of HPR motors stopped that day when I realised that a tilt meter should be mandatory at a certain level of Ns.

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Went out today and got myself a new De-Walt 14" cut off saw with a carbide wheel. No more being afraid of cutting fiberglass or bluetube.

I got all the chutes and kevlar shock cord, etc., etc., in the boilerplate airframe, and weighed it all to get a better idea of what we are looking at.

Sustainer - 3602gr / 7.67oz
Booster - 4765gr / 10.36lb

Stack - 8367gr / 18.04lb

Still need to get the sled, electronics, etc., onboard. This should add a few ounces including the all-thread, fasteners, sled, electronics and battery; but compared to the current weight, it's not going to throw it off that much, and it should all be in 'the right place'.

1 week to go
until first test flight. We may be looking at an CTi M-1830 or AT M-1297 to an EX L-1483 if we don't get a chance to do a mix party beforehand. If we manage to get the AT Hei system before the launch, we will be M1830 to M1297

According to RockSim these give us a test flight of;
M-1830 to L-1483; Alt - 20100; Top Speed - 1887 ft/sec
M-1297 to L-1483; Alt - 21105; Top Speed - 1874 ft/sec
M-1830 to M-1297; Alt - 23300; Top Speed - 1870 ft/sec

weights 7-22-17.JPG
 
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Darth Numbling ready to get medieval on some tubing!

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Sith Powers FAIL

Darth Numbling realizes that he is but a Padawan when it comes to power toolz. That thin blade is for metal (coz it sayz on the side) and I need a tile or ceramic cut off blade which is thicker than this.
Why? Cos as soon as this blade touches the FG tube, it bends a little and so cuts a nice line at an ever so slight angle.
Work around? Carefully transfer cut tube to bench and circular sander.

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Before going back and fixing the fubar with the tubing, I manage to find the stack of oversized 3' bulkheads that i got from Crazy Jim a couple of years back. Down to my last 3! Chucked them on the drill and created myself another stepped lid.
 
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Pete says that he wants to be Tryllian in this build. I have to be Arthur, coz I am English. Erik, sorry, but you are now Marvin.

Anyhoo... AV Bay ... Voila .. Yes, I went for a caliber and a half for the overlap, although I already see a rebuild where the whole AV bay would just bolt inside of an airframe tube. I dunno why I never thought of this before, but, this build has got me thinking about all sorts of angular sheer and stress forces. Taking out two more 'joins' (top and bottom of AV bay airframe, where they meet switch band) should stiffen up the stack. Just a thought.

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At the moment, the antenna is just resting against the floor pretending to be connected. I pulled out my SMA extension adapter and realized it is completely the wrong sex (ooh eerr!). I need to get another one, but when it comes, it will be installed through the bottom AV bay lid. At apogee it hangs free. With the pipe bolt as a shock cord join to the AV bay will hopefully carry the quick link in such a way that neither should interfere with the antenna, but, it is a REALLY whippy whip, should work (1/2 wave).
 
so, everything is now more or less square to each other, and the correct length.

this thing now look ghastly with no colour matches at all... love it

AV bays now 95% complete and awaiting electronics; lids, allthread, etc., all done.

Electronics should finish this bird.

My ten year old helped with the vinyls. Need a cheap clear coat on them.

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OK... after retreating to the garage and avoiding the nasty little bitie insects outside, I got myself a coffee and prepared for a night of sims.... yeah... you know you like it...

I managed to shave (literally...) some weight off the sustainer, and I had realised that I had measured and weighed the booster incorrectly last time

Dry Weights - Sustainer 7lb 4.5oz Booster 10lb 4.8oz Stack 17lb 9oz

CG - sustainer 39.5" stack 76"

I made an eng file with the CTi M1830 and the M840 in it to run through RASAeroII

Lets see what rocksim says first; Max Alt 27,873; Max Velocity 1611 ft/sec

vogon poetry rocksim simulations.jpg

Lets put all this into RASAeroII

vogon poetry RASAERO test settings.JPG Vogon Poetry stack RASAeroII.JPG

and run the tests
vogon poetry RASAERO test results.jpg Vogon Poetry stack cd RASAeroII.JPG Vogon Poetry sustainer cd RASAeroII.JPG

M1830CS to M840 - 85,000ft and 2,975ft/sec

erm... nope... that must be wrong, but I can't find out just where?

OK... dropping the sim over to OpenRocket to see what it says

45,740ft 2,266 ft/sec

Ok these numbers seem more realistic than either of RockSim or RASAeroII

vogon poetry openrocket sim.jpg

I have no idea what is going on, but, I think I like the OpenRocket numbers and will go with them.

I am including the files in case you want to have a look yourself
 
I have no idea what is going on, but, I think I like the OpenRocket numbers and will go with them.

I get 81K launched from 4K feet. Not sure where you're flying this one from.

My experience is that on clean rockets, I get about 90-95%% of the prediction. Suggest you not discount RasAero.

Petty high top-end speed by the way.

Jim
 
I get 81K launched from 4K feet. Not sure where you're flying this one from.

My experience is that on clean rockets, I get about 90-95%% of the prediction. Suggest you not discount RasAero.

Petty high top-end speed by the way.

Jim


Brothers site has an elevation of 4500ft.... but there is no way I am unleashing those motors at that site.
It also seems that we may not actually NEED an N in the booster to meet / surpass out criteria. Originally, Pete threw out "higher than 50K and Mach 2.5", I think that there are quite a few M's that we can stick in the booster that may do. I think the real problem is the long burn M840. Well, problem isn't really the correct word :facepalm: Seeing as I have four commercial M loads available (M1101, M1830, M840 and M1297) I thought of simming with what I had first. Yes, we will have a 5 and a 6 grain EX M, or two, available for BALLs, I really need to start thinking.

The only real "worry" that I am starting to have are those sustainer fins, but, Mike makes a damn good product. I may want to revisit that design though.

I lied.... now that this is a reality, and is sat here in the garage starting at me, I think that I am starting to develop a lot of little worries.
 
Brothers site has an elevation of 4500ft.... but there is no way I am unleashing those motors at that site.
It also seems that we may not actually NEED an N in the booster to meet / surpass out criteria. Originally, Pete threw out "higher than 50K and Mach 2.5", I think that there are quite a few M's that we can stick in the booster that may do. I think the real problem is the long burn M840. Well, problem isn't really the correct word :facepalm: Seeing as I have four commercial M loads available (M1101, M1830, M840 and M1297) I thought of simming with what I had first. Yes, we will have a 5 and a 6 grain EX M, or two, available for BALLs, I really need to start thinking.

The only real "worry" that I am starting to have are those sustainer fins, but, Mike makes a damn good product. I may want to revisit that design though.

I lied.... now that this is a reality, and is sat here in the garage starting at me, I think that I am starting to develop a lot of little worries.

Don't worry . Do the M1830 to a M840. You will be fine . Don't panic . Just gonna send it.

Eric
 
For the moment... I may have to put together a 75 to 54 adapter for the upper stage.
 
I have been trying to calm my nerves a little by taking a step to the side and seeing what i now NEEDZ!

Picked up an EasyMini off another forum user a couple of months back... I think this is the perfect project for a backup backup! and this one will go in the sustainer either as well as, or as replacement to the StrattologgerCF that I put aside for the backup charges. (if I can get all 3 in, I will)

I am also looking for a bee for RDF tracking. I like supporting locals, and this dude is just down the road from me!
Beeline MP 100mw Transmitter beacon
https://www.bigredbee.com/zc139/index.php?main_page=product_info&cPath=65&products_id=181
 
Girl Scout camp started this week. Lots of little kiddles to corrupt! Things are going to slow down a lot.
 
Class 3 / 50K form and 'application' filled in, filed, accepted..... if all goes well... we are on for BALLS..
 
Hope you will be there this weekend for the test run...

HHGTTG... really?

A little more information about the BALLS flights that we have planned this year.
Team Numb (Pete Ekstrom, etc) have been building a rocket that flies a KEG of beer. People who have been to BALLS over the past few years may have seen a couple of these.
Well, Team Numb has been raising $$$ to attempt a TWO STAGE keg rocket. I believe that project may fly this year.

"So Long and thanks for all the Beer!"

Then we have this build thread " Vogon Poetry "

...and I have one of these Loki 54mm M motors

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Which is 'Mostly Harmless'

and we need proof that I am a REAL ... and ORIGINAL geek...

I can't actually remember when i bought this, but it has followed me around for years like a faithful towel. Not been played yet.

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The original Radio play on LP!

May you never lose your towel.
 
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Some parts came today.

Sustainer electronics in place..

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I want to replace the wire aerial on that TeleMega with an SMA mount, extender to the bottom bulkhead, and a good antenna on the outside of the bulkhead. This will have to do for now.
 
and... the interstage gets electronics. Still need switches here.
That purple board is a TeleMaybe. Someone built a couple of TeleMega's as college project or something. I got one, and just about got it working. It needs a test flight.

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I got an Ellis Mountain case here, with the internals, nozzle carrier, double forward bulkhead... and we had an idea.
Pete got on it today... we have hei


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UPS brought Amazon goodness tonight. Edge mount SMA connector, extension lead, various antenna, and some other stuff.
Spent the evening upgrading all the antenna, testing, programming and setting altimeters, re testing. I even got around to connecting up and testing the Purple TeleMaybe, it seems to work and chirp all the correct chirps. I am set it up as backup backup, wont be using telemetry on it as i dont know 100% how much of it works.
Did final weights, etc.. ready for the weekend. past 3am... i am tired.... leaving tomorrow.
 
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