Marine biomimetics

Y3kankerous

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Like many people, I really like biomimetics - artificial things that are inspired by nature - and there are some great designs I have noticed in threads.
Both in function - like the various maple seed designs where there is a common aerodynamic purpose, and also extending to aesthetic, for example, @lakeroadster 's columbine flower

I had a couple of ideas about marine organisms that might have both interesting commonalities between hydrodynamic and aerodynamic properties, but hopefully will also look nice!
The first is a jellyfish and the second is a cephalopod. I haven't found any threads on models along these lines, maybe I've missed them but maybe not that surprising as its a bit niche! Although there are definitely related designs and people may know more widely of similar builds.

1647594024355.png
(wikipedia)
For the cephalopod, I started thinking squid but maybe an extinct belemnite (see pic) would be easier as the conical body is much longer and the flukes are smaller and further back.
To deal with the flukes I am thinking maybe some sort of psuedo GDS arrangement with intakes near the eyes and motor in the head to put the CG forward and make up for the lack of conventional fins. Probably with a transparent cone at the aft to give stability and also keep the tentacles (high T silicone tubing?) out of the exhaust. I would love the tentacles to be flexible but rigid ones that acted as tube fins may be more realistic, maybe a mix... This needs quite a bit more thought and is definitely still in the less-than-half-baked category!

The jellyfish doesn't seem as bad because I have seen many designs based on a dome which to my understanding is an inherently stable geometry (within certain limits).

So I am going to try this first.

Of the various species of jellyfish, the compass jellyfish (Chrysaora hysoscella) looks like a good one to model on, as it is quite regular in shape to aid the aerodynamics, very recognisable with some nice markings which should translate onto a transparent dome, plus the tentacles are not too long, so these can be sized to avoid them being toasted by the hot exhaust (as well as hopefully using something a little heat resistant or at least not flammable).

1647593920158.png 1647595531428.png
1647595792327.png 1647595942915.png
(wildswimmingcornwall.co.uk, fineartamerica.com, marinespecies.org, journeyz.co)

It even has a large straggly looking central tentacle which may be mimiced by the turbulent smoke trail (maybe a smokey sam reload which by luck I have on order...).
 

Y3kankerous

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I have found a transparent ~23 cm dia plastic dome which was a disposable salad container, that has since been used as a lunchbox and then for holding modelling clay. It can now be up-cycled as a rocket powered jellyfish! Probably not what the original vendor expected lol
My main consideration is its rigidity, but it seems OK as it only mildly flexed when I suspended it by two edges with a 3 kg weight in it to very roughly simulate the stress from a low-thrust E motor. Realise this is a poor simulation of dynamic stresses but seems at least a rough guide. The dome has a slot closure running around the edge which I was tempted to trim as will not be very aero... but I think helps with rigidity and makes a handy place to glue the tentacles so gonna leave it on.

IMG_20220316_075756-crop.jpg

For the motor mount, i'm using 24mm phenolic tube mounted in some 80 mm post tubing which by happy chance fits neatly into a ridge in the middle of the salad bowl. I like the idea of motor rear ejection with a large streamer which will add to the jellyfish look (OK it will be upside down!), but I think that this will be for a scale up, partly because I think these parts will only come to around 100g so it will be fine to have it tumble recover with its large surface area. I also can't get the ejection times to match up with a reload because they don't go short enough (keep coming across this problem with large surface area models...), but might stuff a bit of ribbon in the top vent and see what happens.
I'm trying out some more MP-ish methods and materials for this model, so as well as using phenolic mount tube, I'm making a forward bulkhead from plywood to distribute the thrust and using epoxy (rapid set for now) rather than wood glue, esp as the wood glue doesn't bond very well to the dome plastic.

I have done a very quick OR sim to satisfy myself that this all isn't too daft.
This uses the short/fat Cp drag hack from PoF 154/158/162 which seems valid and simulates two flights I have in mind, the first on a D9 (with adapter) to test it out, then a more exciting one on E22-SS as my new Pro24 reload case just arrived.
1647598010543.png
Interesting to see that it predicts a lower apogee for the E22 than D9, which in my interpretation is due to the higher thrust and shorter burn for the E being less efficient (in terms of altitude) for a low mass, very high drag model, despite the higher impulse. The geometry is great for slow moving jellyfish in a dense medium but very bad for getting to altitude quickly as all the inertia at the end of thrust is wasted. So a lower velocity, longer flight results in lower overall losses to aero drag.
The slow blade penetrates the shield
I'll plan to attach an altimeter for these flights to see if this prediction is played out.
As this all seems OK (tell me if I'm wrong!), I will get on with glueing the parts today then start thinking about tentacles and stripes. Need to get on as flying day is on sunday!
 

Funkworks

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I've seen birds, sharks, dragons and sandworms in TRF. Having all these bio-rockets together in a list or thread would be interesting. Lots of possibilities. I like it!
 

lakeroadster

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Cool idea. Art imitating life. Totally foo-foo.

It has to have some tentacles, or else it'll just look like another Jupiter II.

Maybe something as simple as some Twisted Nylon Mason Line. It's available at most hardware stores. And since it's nylon you can cauterize the cuts so it doesn't unravel.

Looking forward to updates.
 

neil_w

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I have found a transparent ~23 cm dia plastic dome which was a disposable salad container, that has since been used as a lunchbox and then for holding modelling clay. It can now be up-cycled as a rocket powered jellyfish! Probably not what the original vendor expected lol
My main consideration is its rigidity, but it seems OK as it only mildly flexed when I suspended it by two edges with a 3 kg weight in it to very roughly simulate the stress from a low-thrust E motor. Realise this is a poor simulation of dynamic stresses but seems at least a rough guide. The dome has a slot closure running around the edge which I was tempted to trim as will not be very aero... but I think helps with rigidity and makes a handy place to glue the tentacles so gonna leave it on.

View attachment 509873

For the motor mount, i'm using 24mm phenolic tube mounted in some 80 mm post tubing which by happy chance fits neatly into a ridge in the middle of the salad bowl. I like the idea of motor rear ejection with a large streamer which will add to the jellyfish look (OK it will be upside down!), but I think that this will be for a scale up, partly because I think these parts will only come to around 100g so it will be fine to have it tumble recover with its large surface area. I also can't get the ejection times to match up with a reload because they don't go short enough (keep coming across this problem with large surface area models...), but might stuff a bit of ribbon in the top vent and see what happens.
I'm trying out some more MP-ish methods and materials for this model, so as well as using phenolic mount tube, I'm making a forward bulkhead from plywood to distribute the thrust and using epoxy (rapid set for now) rather than wood glue, esp as the wood glue doesn't bond very well to the dome plastic.

I have done a very quick OR sim to satisfy myself that this all isn't too daft.
This uses the short/fat Cp drag hack from PoF 154/158/162 which seems valid and simulates two flights I have in mind, the first on a D9 (with adapter) to test it out, then a more exciting one on E22-SS as my new Pro24 reload case just arrived.
View attachment 509870
Interesting to see that it predicts a lower apogee for the E22 than D9, which in my interpretation is due to the higher thrust and shorter burn for the E being less efficient (in terms of altitude) for a low mass, very high drag model, despite the higher impulse. The geometry is great for slow moving jellyfish in a dense medium but very bad for getting to altitude quickly as all the inertia at the end of thrust is wasted. So a lower velocity, longer flight results in lower overall losses to aero drag.
The slow blade penetrates the shield
I'll plan to attach an altimeter for these flights to see if this prediction is played out.
As this all seems OK (tell me if I'm wrong!), I will get on with glueing the parts today then start thinking about tentacles and stripes. Need to get on as flying day is on sunday!
Flight simulation should be done without the base drag hack. You will likely need to override the CG to some fantasy value very far forward to make it stable for flight (again, this is just for simulation purposes).
 

Y3kankerous

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Thanks for the interest, comments and excellent suggestions.

Having all these bio-rockets together in a list or thread would be interesting.
Would definitely like to see this...
Totally foo-foo.
Yessssss!!!
It has to have some tentacles,
Strongly agree.... I have some high T silicone film and just looking at cutting this into multiple thin wriggly wiggly tentacles that will probably stick together
Kraken and King Kraken.
I knew they would be there somewhere, foolishly I searched for "squid", should have known better. I bet there are a couple of cthulhu-alikes out there too.
maximum squidlyness
Definitely what I need
Flight simulation should be done without the base drag hack. You will likely need to override the CG to some fantasy value very far forward to make it stable for flight (again, this is just for simulation purposes).

I picked up this commentary on some previous threads about using the base drag hack and completely failed to understand... but I now get it I think....

The stability simulation (relative position of CP/CG and hence stability cal) needs the base drag hack to give a reasonably realistic estimate for these short/fat geometries.

The flight simulation (apogee, velocity, timings etc) will be somewhat wrong with the base drag hack (presumably because it will think there is a cone stuck to your model), but will also be wrong (very very wrong) if the geometry predicts its unstable, so the CG must be manually overridden with a separate CG hack.

Effectively they need to be treated as separate simulations with completely different hacks that are mutually incompatible.

I had a try at this altho had a bit of a job moving the CG further forward than the front of my fore component (which makes sense in the real world), probably due to being very inexperienced with OR. Moved as far forward as possible to the front of the dome, which gives ~0.06 cal (better than negative!) and increases the predicted apogees from what I had with the base hack by approx one third. In the end I managed to trick it by putting a infinitesimally thin coupler off the front of the dome then manually typing in the CG, i'm fully aware there will be a better way to do this... This did change the CG position and stability so I could get this to > 1 cal. There was in turn an effect on the flight predictions, but only by a percent or two, so there is not a big sensitivity in the flight sim to cal, which also improves my confidence that these hacks are doing what I want, ie they don't give massively different predictions from small changes in input parameters.
Thanks for this advice and clarification.
 

Y3kankerous

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interestingly the manual calcs which I have always relied on prior to starting to use OR are giving apogee values nearly 50% lower than OR with the CG hack (or around 25% below the unreliable ones with the base drag hack). Guessing its basically because the drag is so high its dominating everything else, and is in turn very sensitive to drag coefficient - very difficult to estimate for these strange not-very-aero shapes.
Shows the same inversion on D9 vs E22 though (but made me notice E22 is 24 Ns, ie only 20% greater than D9 anyway, which is certainly part of it).
Hoping for some straight ish flights that might allow a comparison, but that is probably even more unrealistic for a dome with tentacles!!
 

Y3kankerous

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The epoxy cured nicely overnight and it all feels very good and solid.
IMG_20220319_075938.jpg
Going to reinforce slightly with 20mm wide strips of 1/8" ply so the mount has more than just the front fillet.
IMG_20220319_080103.jpg
Drilled a hole in the front plate for a rod guide and will use a bit of wide drinking straw set off slightly from the mount for a lower lug.
Started playing a bit with the silicone film I have... cuts easily and makes nice thin wiggly tentacles. It sticks to itself a bit but nothing a bit of talc shouldn't worry. Also adheres very well with cyanoacrylate.
IMG_20220319_085547.jpg
If anything they are a bit too life-like, very transparent and maybe not that conspicuous on the pad.
More problematically I did a quick flame test to see what wd happen if long tentacles wiggled across the motor exhaust. I was hoping that because silicone is reasonably T resistant, it might just singe a bit, but it very readily caught fire and didn't want to go out. Tried it with plumbers silicone and got the same result.
My hope was that I could get away with slightly longer tentacles because they will probs b pulled into the low pressure area behind the dome meaning a longer path to the nozzle so less likely to get directly toasted. Because they burn so well I don't feel like risking it so need to go with shorter strands that can't reach the nozzle at all. Strands of nomex should work but probably don't have enough. Bit more thought needed...
 

Y3kankerous

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These are really fantastic rockets, I can't even choose a favourite! That said it probably is the squid. I'm amazed those streamers don't get toasted even with the cant, are they fire retardant or just don't get caught in exhaust?
Although the true path can never be fully perceived, events have revealed to me that motor cantomancy is something that I need to better assimilate before further expanding the sphere of my oddroc aspirations.
 

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These are really fantastic rockets, I can't even choose a favourite! That said it probably is the squid. I'm amazed those streamers don't get toasted even with the cant, are they fire retardant or just don't get caught in exhaust?
Although the true path can never be fully perceived, events have revealed to me that motor cantomancy is something that I need to better assimilate before further expanding the sphere of my oddroc aspirations.
On average one or two would get toasted every flight on the squid. Super easy repair, just trim and Scotch tape any bits that fell from the sky.
 

Y3kankerous

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I finished the jellyfish and flew it last weekend.... To release its inner jellyfish-ness, I added 16 silicone film tentacles glued with cyanoacrylate and then spray painted the dome white at the centre merging into transparent around the perimeter. I dusted the tentacles with a little talc to stop them sticking and make them ever so slightly more conspicuous. Final decoration was done on the field! Stripes based on the real animal. Front-on it looks a bit like an aggravated eyeball, but unmistakably a jellyfish from the side.
IMG_20220320_071328-crop.jpg IMG_20220320_112308 crop.jpg
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Launched this on a D9 (with 24 mm adapter) as a test flight and it went very well considering it would probably have preferred to be the water rather than the air! Got some appreciation on the field too for wackiness factor!

🎼Been, done, seen, bout anythin.... When I see a jellyfish fly!!!!🎼
View attachment TRIM_JF.mp4

Thanks to @PhilC for these pics...
Small jellyfish set up.jpg

Small jellyfish launch.jpg Small jellyfish flying.jpg

After close post-flight inspection, I could see that the epoxy fillet on the dome around the outside of the post tube had come away slightly from the plastic dome, so decided to play it safe and not to go ahead with the E22. Looking at it more carefully later, the rest of the glue actually seems very solid, but am planning to peg and epoxy through to a ply front plate and re-glue the existing fillet with cyanoacrylate which should bond permanently to the dome. There are also a few mods I am considering…
*adding more colours to the paint job to be more jellyfish less eye
*removing the outer rim for better aero and gluing this as a reinforcement on the inner rim
*adding asymmetric radial silicone ridges on the dome for extra jellyness and to get a little spin
*adding longer nomex/kevlar thread tentacles
*a pop-out front plate to enhance the tumble recovery
Also have this idea about adding a couple of low thrust 18mm boosters to do the ejection but need to think it through a bit more.

Now thinking hard about some more models along the same theme.
I have found a couple of old water cooler bottles which are ~30 cm dia, light + rigid and just right to be upcycled into 29mm jellyfish!!
IMG_20220324_113116.jpg
 

Y3kankerous

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Here is a very quick sim for the belemnite extinct squid... It will use a clear cone as a fin with rubbery wiggly tentacles fore of this so they are held out of the exhaust and can wiggle as much as they like. Planning on recessing the motor quite a bit to help stability and adding slots in the cone so its a lickle bit GDS.
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Also like to try a transparent comb jelly with pieces of old drinks bottles, plus the silicone film to make flexible fins on the fore which will fold flat under thrust to allow it to be stable. Again there would be slots in the rear fins to allow motor at the fore and bonus GDS stabilisation
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(sciencenews.com)

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With flexi fins pushed flat by air flow....
1648124895870.png
 

Daddyisabar

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Very good. Get a thick. old fashioned stainless steel launch rod, easier than a modern rail. The major problem is exhaust burn as any bit the comes close to the flame will be toast. Good to see you going for looks, the most important aspect of oddrockery. :) Some LED lights for a night launch would be awesome on the Jelly. I have played around with the idea of a canted cluster Portuguese Man of War and an Angler fish. The Angler fish would be a big mama with tiny little males hanging off the back attached by their teeth for stabilization. A nice stiff lumination rod with a lead ball at the end for balance.
 

Y3kankerous

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Been a few months but I've been cracking on with these projects... sorry no intermediate updates....
I did those various mods on the original jellyfish, removed the slightly ugly outer ring, put a plastic bolted front plate on and added 13mm boosters, then beefed up the tentacles using nomex tape and thread this time. This charred rather than burned in my flame test so I made the thread tentacles quite a bit longer due to not being worried about burning strings falling from sky. I also used some silicone sealant to make rubbery rifling on the shoulder to encourage the jelly to spin. The boosters were highly canted and rotated, idea being that as well as encouraging the spin a little (only using 1/4 or 1/2A), they would rear eject quite a bit earlier than the main motor and deploy a pair of mini-streamers. This would slow the descent a little, although mostly to look nice!
IMG_20220430_074603.jpg IMG_20220511_191736.jpg
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I launched this config with a D12-3 and went off well. Only one of the boosters took, I think the match igniters don't fit naturally into either the D or the 13mm motors, but the one that did take did what I wanted and the asymmetry didn't seem to affect the flight, suggesting I'd got the canting worked out more of less (although mostly prob due to the much much larger central thrust).
No vid of that launch I'm afraid (or not one worth uploading anyway!). I was encouraged by this turn of events so at this time got cracking on the BIG jellyfish project (29 mm motor) and the belemnite extinct GDS-ish squid. More about that shortly.
I noticed that in the D12 flight the plastic dome had got kinked slightly in that flight, so I did another mod, by epoxying in a card ring against the forward dome, to strengthen it up, also fixed onto the main central tube.
IMG20220620203910.jpg
With the reinforced jellyfish I was ready to try it with a low power composite (which is what I had been building up to...) and launched on a CTI P24 1G E22 (smokey sam). As well as the extra poke, the reload meant it was easy to remove the ejection charge which was not needed. This time neither of the boosters took, I think the initial pressurisation simply blew away the tape match I had laid behind it. It flew very nicely anyway tho and the black smoke was cracking!! Not bad for an old throwaway salad bowl and some post tube!

View attachment VID20220619135149b.mp4
 

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boatgeek

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I'm not sure how I missed this thread last time around, but I am also a big fan of biomimicry. The jellyfish is great, and I'm looking forward to seeing the belemnite.

I have a few in fin shapes though not in the body shape:
Tuna
Fruit bat (not a build thread, but the picture's not bad)
Dimetrodon

And here's a link to @Daddyisabar's build thread for the squid. The story is better than the rocket, and the rocket is very cool!
 

Y3kankerous

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Thanks! Also for the links, very nice rockets! Hadn't seen the squid vids before so that was great.
There was a good comment on the squid thread that all rockets should have a story, which I definitely agree with!!
 

Y3kankerous

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For the belemnite, the bit that took the longest was finding a cone tail that was the right shape for my idea with the tentacles. The premise was that this would provide stability by acting as a cone fin, with the motor mounted at the fore (narrow) end of the cone. It would have duct inlets cut into it to avoid Krushnic effect and by virtue of the associated intake be slightly GDS (pseudo-fin) but mainly adding to stability by allowing the motor (and hence CG) to be placed much further forward compared to the CP contribution of the cone. This would allow the look I was going for that the tentacles would extend aft of the motor and the jet/plume would originate in the mouth region between the tentacles, as per a real squid.
I started with 18mm motor but the prize is in a subsequent scale up to 24 or 29 mm so I can use APCP reloads and smokey sam propellant so it will look like black squid ink being ejected at a foe :D:D😃😃 Its always nice to have a vision!
Once I found a suitable bottle it was fairly straightforward to set up the motor mount and a series of couplings to make the thinner pointy fore called the guard or rostrum apparently, which is where it would separate on ejection.
IMG20220608174245.jpg IMG20220608174801.jpg IMG20220618105208.jpg

IMG20220618153614.jpg IMG20220618105235.jpg
A layer of non-flammable nomex tape on the inside of the plastic cone was intended to help a little with any exhaust splash. To help with getting the motor fitted up inside the cone I put a little wire loop so it could be more easily pulled back from side and then the motor just popped in.

I also wanted to have some decent sized canards for the front fins, even though these would substantially detract from stability. The SIM showed it was OK and the model was small enough to swing test and with a little more nose weight it went fine. This meant that any GDS effect was a bonus and that the model should be stable throughout flight. The NC was whittled quickly from balsa with a couple of rings of split BT to get a taper and fit.
IMG20220618172614.jpg
Did a quick paint job choosing a nice ocean blue with a couple of lateral streaks of glitter sealed with clear PVA. After trying a few ways of making lightweight tubes and some spare bit of flexi pipe (which were too heavy), the all-important tentacles were made with pipe-cleaners, coloured to fit with the body. I use a pin heated in a flame to cut the inlet ducts in the plastic cone as well as a slot for the launch rod. This was quite accurate and seemed to avoid weakening the plastic as I expect cutting or drilling holes might have. I tried to get a total duct area according to PoF 379, but was mostly by eye to be fair.
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Y3kankerous

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So it launched on a B4-2, flew nicely and recovered on a mylar streamer. Fair to say it may have lost a little power due to the GDS-ish cone arrangement, as also evidenced by some modest melting of the aft end. This could probably be improved with more/larger ducts to improve the induction and a slight shortening of the cone. My guess is a more flared shorter/wider cone would also probably largely resolve this, whilst maintaining the base drag stabilisation.

View attachment VID20220619141145b.mp4
IMG20220625111233.jpg IMG20220625111307.jpg

I was well happy with the final look of the model and also that this gives a good basis for a LARGER belemnite to terrorise the deep (maybe this will be the plot of Jurassic World 27). Watch this space....
 

Y3kankerous

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Here comes an update on the BIG jellyfish…. I did the build and first flight back in the summer then got a little overtaken by daily life but have only just getting round to a write up.
 

Y3kankerous

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So, the idea I had was to cut the top off an 18 L water cooler bottle and then fashion a rear eject to take a 29 mm reload and this is more or less what I did. A quick sim (with the base drag hack) showed that it should be nice and stable and would go off well with a one grain (without reading too much into the actual flight predictions).

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IMG20220608174201.jpg
Found someone giving away empty water cooler bottles that had been used in classroom experiments were no good for drinking water anymore. They are fairly light, tough and very rigid. Needed a bit of care to cut neatly but all good. I made up a motor mount from phenolic tube, ply and epoxy and then fitted this into a post tube with some little cut outs to distribute the loading and also make sure that the front end located neatly without binding. I tried a few things to pad out the fore ring to let it compress under thrust, so the aft ring only loaded at peak and so distributed better. A piece of rope was the best selection in the end as a compromise with something that would not compress too much but also wouldn't lock up, plus was not too flammable.
IMG_20220511_085950.jpg IMG20220618100051.jpg
At the front of the mount an improvised star shaped fitting with various small features aimed at reduced point loadings during thrust and allowing the ejection charge to expand and chuck the bobbin out the back rather than shattering the mount or blowing out the front.
IMG20220606215449.jpg
I did a couple of quick calcs which confirmed my guess that despite being moderately massive it would be fairly draggy so it was not going to coast far and on a one grain already be dropping fast by the minimum ejection delay. To try and slow the initial descent from apogee, I tried to repeat my idea of using two small BP boosters to deploy small paras as drogues earlier on. This would either slow the descent to give more time for the minimum delay or, potentially, deploy the main chute by pulling it out the back. The boosters and mini-chutes were set up so that if they didn’t eject then they would just deploy at the same time as the main one and if they went during thrust then they would likely just get toasted and not mess the flight up too much.

IMG20220618100038.jpg
 

Y3kankerous

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To fit the post tube onto the main body I epoxied it in firmly and then used four sturdy cable ties onto the bottle via eight small cut outs melted with a hot pin, with some ply discs to distribute the load.
IMG20220619101705.jpg
I now had a decent reel of yellow Kevlar cord and cut lengths of this to make the tentacles. Just for fun I used some silicone sealant to make rifling on the outer edge so it might spin a little and even out any wobbles. A bit of stick on foam and some free hand decoration by the nipper and it was ready to go for the next club flying day.
IMG20220618154432.jpg IMG20220619101629.jpg
 

Y3kankerous

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It was my largest and heaviest model to date, plus my first try with the 29 mm reload and I was a little apprehensive. This strangely got worse through the day as all my other flights went off straight first time and I was sort of starting to think how nice it would be to have a clean sheet. Part of my brain (not sure if it was the good part or the bad part!) was definitely thinking of reasons to pull the plug. Why hadn’t I just gone for a simple 1N3F to start with! However, everyone at the club who had taken a look was super encouraging and pointed out all the considerations and SIMs which were showing up fine. So there we were… the final flight of the day with the jellyfish looking just a tad heavy on the biggest rod, angled away from the firing line, but ready to go.
IMG20220619160937.jpg
Happily it didn’t disappoint and went off like a cork out of a bottle with the 73F30 classic long burn CTI. As predicted it didn’t get a long coast and the “clever” boosters did not function, so it was a bit of a late deployment, but it stopped pretty much dead in the air as all three chutes deployed at once, with the main body on a long piece of shock cord just before it hit the tree line. Didn’t have a scratch on it.

Thanks to one of the guys at the club who got a nice video.

View attachment VID-20220619-WA0001b.mp4

From looking at the boosters afterwards, the tape match hadn't caught at all and in the vid on slomo it seemed like the initial internal pressurisation of the APCP just blew it all away without lighting it. I had tried an indirect ignition for the boosters but next time would do it on the same igniter i think.

Think the next thing is to do with this model is a 2 grain G and maybe work up to a 3 grain H54 long burn!! That would certainly solve the ejection delay...
 

Y3kankerous

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For the benefit of accuracy (and for anyone counting thrust...) I realised that it was a 56F31 classic reload instead of what I put above which was the simulation not the actual flight.
 
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