A supersonic Apogee Aspire...

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A nose cone will almost certainly tumble, particularly a tail-heavy one (as yours probably is, given the Eggfinder). Maybe not a fast end-over-end tumble, but it won't be ballistic. Your simmed streamer speed (32 m/s) seems way too high. I suspect you aren't accounting for the tumbling drag of the separated airframe itself (OR does not do this by default, and on all but the smallest rockets, airframe drag will overwhelm streamer drag)? On my cardboard framed high power rockets, "drogueless" descent speed is more like 15-20 m/s (OR sims much higher than that).

I agree, the nose is tumbling, and the ~20 m/s measured by the A3 seems reasonable.

The most recent sim from snrkl in post #57 shows ~20 m/s streamer recovery. Not sure where you see 32 m/s?

Anyway, streamers offer very little additional drag, and simulating them is questionable.
 
I agree, the nose is tumbling, and the ~20 m/s measured by the A3 seems reasonable.

The most recent sim from snrkl in post #57 shows ~20 m/s streamer recovery. Not sure where you see 32 m/s?

Anyway, streamers offer very little additional drag, and simulating them is questionable.

From post #42:

I’ve opted to go with a 6” chute over the Mylar streamer - the Mylar was bringing it down at 32m/s (~100km/h) in the sims - the gps, the NC and the f39 RMS together makes it drop like a stone.
 
Thanks all for the input - it’s good food for thought.

One challenge I have is that with such a small airframe
going so high, so fast is that it’s impossible know what actually happens in the air - unless we fit a camera to the airframe which kind of kills this project’s speed/altitude goals...

I’m hoping I’ve eliminated the error that led to the major failure scenario from the f39 flight (nosecone detach) so I’m now free to now make all new errors and cause something new to fail! ;-)

Update: airframe is cut, fins are CAd and epoxied (last night) and I’ve had my first go at fix-it epoxy clay fillets just now.

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Used the “snake” technique and tried pulling a popsicle stick through to shape the fillet - it didn’t work so well so I ended up laying and pushing snakes of fix-it on both sides of the fin root and then smoothing fillets on both sides with gloved index/thumb dipped in isopropyl alcohol.

I used the side of the popsicle stick to push the fix-it material back towards the root of I feathered it too far away from the root.

Seems to have worked... much room for practice, but I’m confident some dowel sanding and some CWF will see it through - to be attempted tomorrow once these root fillets have cured.
 
Isn't epoxy clay a tad heavy for what you're attempting?

It’s based on the instructions by apogee for making the aspire go supersonic:

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The ORK im using has 3mm epoxy fillets added, so I’m hoping the weight is accounted for in the sim.

Plus, the NC weighs 68g with all the electronics, so I’m not too worried about the CG/CP relationship - we still have MANY calibers of stability to play with... [emoji6]
 
It’s based on the instructions by apogee for making the aspire go supersonic:

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The ORK im using has 3mm epoxy fillets added, so I’m hoping the weight is accounted for in the sim.

Plus, the NC weighs 68g with all the electronics, so I’m not too worried about the CG/CP relationship - we still have MANY calibers of stability to play with... [emoji6]
If you're overstable could you trim down the fins a bit? It might be a bit late now but I bet it would help...

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I didn't see it in the thread so sorry if already discussed. Are you going to use a launch tower versus a rod? My Aspire apparently got some "stiction" on a dirty rod and got to about 30' up and folded in half flying on a AT G76G-10. She was REALLY MOVING at that point! On recovery of the parts, you could see the fold / tear started right at the aft of the launch lug... If you think about the vectors involved, it makes sense that there would be stress there in proportion to the "stiction" on the rod. if I were going to try that again, I'd use a tower and omit the lug. My :2: worth definitely not worth a dime. :)
 
Mayhem rocketry fly away guide for the aspire: https://cart.amwprox.com/index.php?...art_product_id=1025&virtuemart_category_id=69
I lay a bead of silicone caulking agent on the inside so it provides some grip after it sets up and still allows the guides to pop off. You can rub the caulk out of the guide if you want to with your finger.

The guides need something to make the fit to the tube a bit tight otherwise the rocket will blast through and the fins will take a hit. I have a pair for my Aspire project. I might do a Tele-Mini vs Eggfinder mini. Kurt
 
If you don't want to use silicone, rubber bands longwise around each half work well & can be varied on a bird-by-bird basis.
 
I didn't see it in the thread so sorry if already discussed. Are you going to use a launch tower versus a rod? My Aspire apparently got some "stiction" on a dirty rod and got to about 30' up and folded in half flying on a AT G76G-10. She was REALLY MOVING at that point! On recovery of the parts, you could see the fold / tear started right at the aft of the launch lug... If you think about the vectors involved, it makes sense that there would be stress there in proportion to the "stiction" on the rod. if I were going to try that again, I'd use a tower and omit the lug. My :2: worth definitely not worth a dime. :)

I hear you. I’ve shortened the aft of the airframe so that the aft end is exactly the length needed for the G80, and I’ve subbed the standard coupler for one that’s twice the thickness.

There is two engine blocks that but up flush with the coupler, so I’m hoping the axial (is that the right world?) forces are as well contained as possible.

As for “stiction” I have some sandpaper in my range box and I always sand/clean the rod before flight.

No towers available at my club but aspera-iii might look at flyaway guides based on results from this flight.

I’ll keep going with this till I get Mach and kiss the 5000’ ceiling at the club...

[emoji12]
 
Thanks all for the input - it’s good food for thought.

One challenge I have is that with such a small airframe
going so high, so fast is that it’s impossible know what actually happens in the air - unless we fit a camera to the airframe which kind of kills this project’s speed/altitude goals...

I’m hoping I’ve eliminated the error that led to the major failure scenario from the f39 flight (nosecone detach) so I’m now free to now make all new errors and cause something new to fail! ;-)

Update: airframe is cut, fins are CAd and epoxied (last night) and I’ve had my first go at fix-it epoxy clay fillets just now.

View attachment 331785

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Used the “snake” technique and tried pulling a popsicle stick through to shape the fillet - it didn’t work so well so I ended up laying and pushing snakes of fix-it on both sides of the fin root and then smoothing fillets on both sides with gloved index/thumb dipped in isopropyl alcohol.

I used the side of the popsicle stick to push the fix-it material back towards the root of I feathered it too far away from the root.

Seems to have worked... much room for practice, but I’m confident some dowel sanding and some CWF will see it through - to be attempted tomorrow once these root fillets have cured.

What I usually with the clay is I actually tape off the area for the fillet as you would with regular liquid type epoxy. Using the snake technique push the clay in and smooth it out. Remove the tape and you have the prefect fillet. What you want to do is take the dip finger in alcohol and smooth the ridges of the tape line so it conforms to the tube, so when it dries you have less shaping and sanding to do. I use needle files and dowels with sand paper wrapped around them. You can also rubber grips of different shapes that allow you to sand and shape your fillets.
 
What I usually with the clay is I actually tape off the area for the fillet as you would with regular liquid type epoxy. Using the snake technique push the clay in and smooth it out. Remove the tape and you have the prefect fillet. What you want to do is take the dip finger in alcohol and smooth the ridges of the tape line so it conforms to the tube, so when it dries you have less shaping and sanding to do. I use needle files and dowels with sand paper wrapped around them. You can also rubber grips of different shapes that allow you to sand and shape your fillets.

I’m thinking my next time doing clay fillets I’m going to be using many of these tips.

All up, I’m not too happy with the quality of the shaping of these fillets. They’re strong but I’m used to doing so much better. I’m quite proud of how I’ve refined my epoxy glue fillets - these ones feel like something I did in the 8th grade (no offence meant to 8th graders... [emoji12])

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As it is, my last flying day for the year is Sunday so if this doesn’t fly then, it will likely be February before I get it up.

Plus, I have a g80 burning a hole in my field box, so it will be going up Sunday (unless the RSO says otherwise! [emoji6])

I also found a flaw in my sim when looking at it on the plane home tonight - fins were set to cardboard (no biggie) but they were set to 2mm thickness.

Updated the sim for their actual thickness and lost 190m of altitude...

New sim has it at Mach ~1.16 flying to ~1300m... (down from Mach ~1.25 to ~1490m)
 
You can make a simple tower out of three pieces of steel electrical conduit, a bucket, and a bag of ready-mix concrete.

It will cost less than twenty bucks and shouldn't take long to build.

The downside is lugging the thing out to the launch site...


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The downside is lugging the thing out to the launch site...

LOL - I can imagine.

I’m happy launching with lugs for now.

I’m planning on getting into buttons with my 2” SCR quake kit build over the Christmas break.

After Christmas I might see if the quake might make a (high!) L1 attempt or whether I’ll look at procuring a 4” mad cow when I’m stateside in mid January. Gotta think about how to get a large bird kit home on a plane!

Oh, and I’ll keep plugging away till I have this 29mm MD - G80 thing down.

I figure with disposable motors, so long as I get my nose cone with GPS and altimeter back, I’m ok losing the rest, conditional on skills progressing and me still enjoying the builds...

Until last weekend I had yet to experience my first losses - so I figure I’ve made my first sacrificial offerings to the rocket gods now - I *gotta* keep going!
 
I've never seen the appeal of the epoxy clay myself.
Tim vM certainly likes the product as it features regularly on his site.
 
I've never seen the appeal of the epoxy clay myself.
Tim vM certainly likes the product as it features regularly on his site.

I figure it’s part of my journey into the learnings of how different materials can be used to solve problems.

CWF covers a multitude of sins:
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There not perfect but they’re better and if I don’t get this bird painted in the next hour I’ll be flying gooey paint tomorrow!!
 
Incidentally, if anyone has any safe methods for accelerating paint cure, I’m all ears...

Except I don’t own a hair dryer...

[emoji12]
 
Bird is painted.

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Slight mod to the paint job to remove the need for masking, so I could paint it in one go.

Garage door and back door open to encourage a “wind-tunnel of drying’ness™️”...

I’ve got about 13hours till this has to be in the car - hopefully it won’t be for naught.

Once the sun sets I’ll likely move it inside and position it under a ceiling fan to encourage hurricane like air circulation.

Maybe even put the AC on a dry heat setting...

Glad I have the house to myself for the weekend - no one to complain about paint fumes... [emoji6]

Time will tell if this works...
 
That looks GOOD!

Thank you sir!

Despite my constant learning curve - I like to think I’ve gotten my head around how to handle a rattle can (or three) of Rustoleum 2x Painter’s Choice...
 
For pinewood derby, I cranked the heat downstairs, closed most of the vents, opened the vent in the bathroom to max, and turned on the exhaust fan. Yeah, that room got quite toasty and had a lot of airflow. Good luck!
 
Rusto 2x just ain’t gonna dry in a day.

I too have heard that heat is the best accelerant. Stick it in a hot car interior in the sun. Yes, your car will stink.
 
In the end I flew it tacky.

Flight was nominal right up until I recovered a nosecone, a streamer and about 1m of Kevlar shock cord.

I picked up some new Kevlar last week and this was its maiden use - long story short I now know what the difference between Kevlar kite string and the Kevlar my local rocketry place sells - the stuff ausrocketry sells is Kevlar coated in epoxy - to stop exactly what I saw today. (They had experimented with the kite string Kevlar I’m using before...)

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Aspera II
Max altitude1462.1 m
Date12/11/2017 9:29 AM
ModeExperimental
Duration2 mins 19 secs
Notes
Max climb rate4907.3 m/s
Max sink rate-5090.2 m/s

Oh well - Aspera III will be built as soon as I can afford the next construction material purchase.

As for the flight, I doubled the Mylar streamer to 2.9m and I’m glad I did - it’s the only reason we could see the rocket (we’ll, nosecone anyway...) descending.

Flight got 1462m (4796’) and I’m convinced it broke Mach.

I accidentally had the Altimeter3 in “experimental” mode - I’ve emailed John Bean to see if the data can be transmogrified back into a rocket flight.

And to my absolute surprise, JUST as I was leaving the site, I saw some locals on dirt bikes in one of the fields trying to put a broken rocket on the fence - I pulled over and there it was: aspera1!!

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Looks like they might have found it by driving their bikes over it:
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But my RMS 24/40 case was still in it.
I’ve cleaned the case out and I’ve just got it soaking in hot water to help clean the burnt residue from the C grain where it burned through the liner...

Over all a good day..

Videos to follow.
 
Aspera II - going to 4796' (1462m) at Mach ~1.1


Shock Cord snapped, NC with GPS and Altimeter3 recovered, airframe lost...


Aspera III in planning - 3rd time is a charm!


[video=youtube;tdX-6FYVQ_c]https://www.youtube.com/watch?v=tdX-6FYVQ_c[/video]
 
Very impressive! Ditch the launch lug (if you can) and go to three fins and I bet you get it. I have built and flown several Aspires and love the kit. A thing I found useful with the clay fillets is to create a fin can with some epoxy. After setting your fins tape off the tube just ahead of the leading edge. Mix up some slow set and warm it up to make it run. Paint the tube on the back of the rocket nice and thin. Remove the tape and let dry. Next sand the brush marks smooth. Now you can set your clay and use a small pice of tubing or whatever dipped in alcohol to pull the final shape. The epoxy will prevent the alcohol from heaving the tube and make the fin area super stiff. My last Aspire is a dual deploy for the Mach and mile high club. She did it but I had to cheat a little with acrylic fins and a lot of tracking powder.

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Is it wrong of me to be thinking about making one of these for an H135?

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Im planning L1 cert in the new year on an H135.

I’m thinking I’ll take two rockets - one of these and the larger airframe.

If I put this one up first and certify successfully, I figure there’s got to be some bragging rights on certifying on a 29mm MD bird right?!

Failing that, I fly the sensible bird...

I wonder if there’s anything wrong with two cert attempts on the same day?


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I wonder if there’s anything wrong with two cert attempts on the same day?

Nothing, except access to H-motors.
In the US, you can buy only one (1) at a time for your cert attempt. I am not sure if the same rules apply in Australia.
If you have a vendor on-site with ample inventory, this should not be a constraint either.

a
 
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