Build : MAC Performance - 3" Scorpion XL on 38mm

Are you allowed to both certify on the same rocket on the same day?

Nick Hutton said:

Are you allowed to both certify on the same rocket on the same day?

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Yes, as long as both attempts are done individually, ie Pyro does all his own launch prep, checks, etc.

Sep 1 - Launch Day - Postponed due to paddock conditions next launch window for us is Nov 3.

But we did manage to play with ejection charges today... mixed results



After 2 fails to separate - we had a small rethink of our caculations and then applied redneck maths, if failed first time, double it... in hind sight, our initial calculations did not allow for the 2 shear pins in booster or payload section. The BP we also have appears to be of a larger grain than the 'other' mix that Alex uses, so further testing required.

Payload worked out to be separation at 1.0g - will re-do the booster separation this coming week. Better to fail today, than lawn dart tomorrow...

Additional Ejection Charge Testing - COMPLETE !



Now to kick back & relax - launch date is now Nov 3

spigalau said:

Additional Ejection Charge Testing - COMPLETE !



Now to kick back & relax - launch date is now Nov 3

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I’ve been doing ground testing in advance of my Level 1 attempt coming up on Friday, September 13. At the suggestion of others with a lot of high power experience, I shelved my pound of Pyrodex and went with FFFFg black powder. Wow, what a difference! Less powder yielded far superior results as compared to my Pyrodex testing (which I was containing tightly with wadding). I’m a convert despite the after-smell.

Ok, a week till launch, how time flies. We are back in NZ after our Bali excursion, what a great break we had. If you ever get a chance to go to Bali, take it - the people are lovely & friendly, the food is divine and the sites are fantastic. Gili Air is awesome...



For Spyro 38 - We have completed all of our on ground testing (electronic & black powder), next week we go live.

A couple of minor changes to the build, we have swapped out the drougue chute to an 18" Ballute and the main chute is now a 5' custom made rotosail. Thank you to BAMA recovery systems for the chutes, they are beautiful !

Fingers crossed, the next update on this thread will be launch & landing pictures.

Time for some post gardening analysis of Spyro 38.

Before:


After:


Flight up was good, nice & stable - flight down was not so good. Lawn dart about 1.0m embedded in the peat within 250m of the launch pad.

Damage Report:

1 x 19" Payload Tube cracked (to be replaced)
1 x EggTimerTRS, needs some repairs - the aerial does look kind of funky though.
3 x LiPo 450 Batteries (to be replaced)
1 x Avionics BulkHead plate (to be replaced)
2 x Aluminum 1/4" all thread rods (to be replaced)
1 x MissileWorx RRC2+ (to be tested)

Not really sure why both primary & secondary flight computers both failed, have suspicion that my dodgy solder attachment gave away on the isolation switch for one failure and the primary FC appears to have dropped the charge battery leads on takeoff. The ignitor leads also took some damage (wires stripped), but I expect this is from the arrival of the ground. All 4 black powder charges did not go off.

I am very impressed with the strength of the MAC airframe, the phenolic canvas held up very well. The damage around the upper payload was caused by nose cone wanting to head in a different direction to the payload tube.

Man, sorry to hear about the ballistic recovery. But it's a good testament of Mac Canvas. And enough survived for a rebuild.

And we have made some solid progress this week.

1) Replacement Payload tube, notched & drilled - ready for wrapping
2) AV Bay - rebuilt
a) Batterys contained within 3D printed Chernobyl style enclosures. Blue terminals secondary, white primary


b) Flight Computers Mounted (Altus Metrum Easy Mini as Primary, MissileWorks RRC2+ as secondary)


3) Easy connectors to screw switches (to be mounted)


4) Test fit in tube


To do:
1) Wrap Payload
2) Wrap Centre Band
3) Fit BAMA Recovery Systems - Quick Softlinks (they are somewhere between Houston & NZ according to USPS)
4) Fly !

End of the tunnel insight

I take it you had second thoughts about reusing the TRS? Have you printed the battery shrouds as a fix for your ideas that the last flights issues may have been due to battery connection issues?

Nick Hutton said:

I take it you had second thoughts about reusing the TRS? Have you printed the battery shrouds as a fix for your ideas that the last flights issues may have been due to battery connection issues?

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The replacement modules for the TRS were not 'cost effective' - I'll look at building a different GPS tracker unit in the New Year (Eggtimer Mini Transmitter) and stick it in the nose AV bay along side the JL2. We still have the hand held tracker from the TRS, so may as well make use of it.

The battery shrouds came about with a change in size of the batteries, dropped from 3 x 2S 450's to 2 x 1S 600's. The 1S batteries are smaller & a lot lighter than the 2S ones, so we came up with a cleaner solution for reatining them. The 3 x 2S got binned.

In post flight / gardening anaylsis, I believe that I had not adequatly secured the TRS charge cables in the terminal block on the board. Looking at the terminal block, the gap was 'big' and on launch she dropped the charge leads and possibly the negative lead off the FC battery.. I'll take that as a learning experience (note: check, check, check again).

The secondary FC appears to have lost power due to a leg snapping on the isolation switch - not sure when this happened, assume before apogee as NIL charges activated. I had bent the legs on the switch band to move them away from the board, so may have created a weak point by doing that.

With Mk II AV bay have changed a couple of bits around, simplified & solidified some bits (dual band isolation switch is now 2 indepenedent screw switches) and I think it looks a lot cleaner now.

I wasn't happy with the crimp rings, so after thinking on it, re-did the connections with a bit of solder & heat shrink. Much happier now and the flex point is moved well away from the solder.

spigalau said:

I wasn't happy with the crimp rings, so after thinking on it, re-did the connections with a bit of solder & heat shrink. Much happier now and the flex point is moved well away from the solder.

View attachment 399468

View attachment 399467

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Eons ago, when I was still in high school, I had a summer job with a small company run by a PE (Professional Engineer). He stressed that a good solder connection was not just metallurgical (the solder portion) but also mechanical in nature. I could not tell from your photos, but did you put the wire through the holes in the PCB and solder them front and back? Tinning stranded wire makes the insertion into the PCB hole a much easier task. I believe that your idea of using heat shrink material as a form of strain relief on the solder connections is a good one. Having the wires soldered so that they exit the PCB at an angle toward one another (10-20 degrees) would also provide extra assurance on the strain relief so that the heat shrink doesn't unintentionally stress the solder joints.

Looks like you are very close - best of luck to you on the post-rebuild flight!

g.pitts said:

I believe that your idea of using heat shrink material as a form of strain relief on the solder connections is a good one.

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Agreed. I use it on many of my connections.

g.pitts said:

I could not tell from your photos, but did you put the wire through the holes in the PCB and solder them front and back?

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Yes, through the hole and then looped back around the base of the wire - soldered fully on both sides, individually shrunk wrapped each wire and then did a larger wrap over the PCB for additional support.

28 days on from 'Operation Spud Finder' we are pleased to say we are 25% complete on our goal.

Level 1 Certification unlocked for Spigalau

However, due to time constraints and the fact that winds were picking up, PyroShark will attempt his L1 in the New Year (Jan 11)











Recovery was approx 4000' away as the crow flies - a couple of cows were interested to see what had landed in the paddock next to them. The landing was very soft, sub 15 feet per second.

I would like to thank the following vendors for their support & assistance, this has been a fun project to do.

Mike @ MAC Performance Rocketry - Airframe & Electronics
Teddy @ One Bad Hawk - Harness & Blankets
Cris @ Eggtimer Rocketry - GPS Tracking
BJ @ BAMA Recovery Systems - Rotosail, Ballute & Soft Quick Links
Gerry @ Aerospace Education (NZ) - Aerotech DMS Motors
Alex @ NZRA - Electronics & Mentoring

Next Steps:
11 Jan 2020 - L1 PyroShark
7 to 9 Feb 2020 - Havoc in the Paddock - L2 for PyroShark & Myself

spigalau said:

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Out of the ashes rose a beautiful rocket. Congratulations on a successful flight!

Gotta love a good descent video [emoji12]

Nick Hutton said:

Gotta love a good descent video [emoji12]

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Sneak preview of Pyro's L1 landing from yesterday... we have COWS !

Ok, so after yesterday, we are now at 50% completion of our goals for Spyro 38. We are both now Level 1 certified fliers, the next step is our Level 2's which we will undertake next month (Feb 2020).

Video from yesterdays flight can be found here:





Main chute deployed at 800' (so the 3rd shear pin worked), but was slow to inflate (fully inflated at 400') - speed under drogue/ballute was around 45fps, under main mid teens.

Congratulations on a nice Level 1 certification flight! Also very nice video editing. Loved the videobomb at the end by the cows.

Update: L2 tests done & passed. Next step this Friday for my L2 launch (J270W) and Pyro does his on Sunday (J425R). Still time to make it to NZ for 'Havoc in the Paddock' this coming weekend...

I’ll see your level 2 launch and join you in the club hopefully

spigalau said:

Update: L2 tests done & passed. Next step this Friday for my L2 launch (J270W) and Pyro does his on Sunday (J425R). Still time to make it to NZ for 'Havoc in the Paddock' this coming weekend...

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Congratulations on getting the test completed - now comes the easy part. In all seriousness, good luck to both of you on the upcoming flights!

Nick Hutton said:

I’ll see your level 2 launch and join you in the club hopefully

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Yes looking forward to this. I assume you will be the guy with the slab of XXXX under his arm ?

We are intending to be onsite for about 10:30am on Friday. Our home for the 3 days is:



Drop in for a coffee, beer, etc...

Good show!

I forget, which is his rocket and which is yours.

spigalau said:

28 days on from 'Operation Spud Finder' we are pleased to say we are 25% complete on our goal.

Level 1 Certification unlocked for Spigalau

However, due to time constraints and the fact that winds were picking up, PyroShark will attempt his L1 in the New Year (Jan 11)

Recovery was approx 4000' away as the crow flies - a couple of cows were interested to see what had landed in the paddock next to them. The landing was very soft, sub 15 feet per second.

I would like to thank the following vendors for their support & assistance, this has been a fun project to do.

Mike @ MAC Performance Rocketry - Airframe & Electronics
Teddy @ One Bad Hawk - Harness & Blankets
Cris @ Eggtimer Rocketry - GPS Tracking
BJ @ BAMA Recovery Systems - Rotosail, Ballute & Soft Quick Links
Gerry @ Aerospace Education (NZ) - Aerotech DMS Motors
Alex @ NZRA - Electronics & Mentoring

Next Steps:
11 Jan 2020 - L1 PyroShark
7 to 9 Feb 2020 - Havoc in the Paddock - L2 for PyroShark & Myself

Click to expand...

Very nice projects. The descent rates on chutes seem to be very slow. D

spigalau said:

28 days on from 'Operation Spud Finder' we are pleased to say we are 25% complete on our goal.

Level 1 Certification unlocked for Spigalau

However, due to time constraints and the fact that winds were picking up, PyroShark will attempt his L1 in the New Year (Jan 11)

Recovery was approx 4000' away as the crow flies - a couple of cows were interested to see what had landed in the paddock next to them. The landing was very soft, sub 15 feet per second.

I would like to thank the following vendors for their support & assistance, this has been a fun project to do.

Mike @ MAC Performance Rocketry - Airframe & Electronics
Teddy @ One Bad Hawk - Harness & Blankets
Cris @ Eggtimer Rocketry - GPS Tracking
BJ @ BAMA Recovery Systems - Rotosail, Ballute & Soft Quick Links
Gerry @ Aerospace Education (NZ) - Aerotech DMS Motors
Alex @ NZRA - Electronics & Mentoring

Next Steps:
11 Jan 2020 - L1 PyroShark
7 to 9 Feb 2020 - Havoc in the Paddock - L2 for PyroShark & Myself

Click to expand...

very nice project. The chute descent rates seem to be a little slow. I would want drogue over 50fps and main 17-20fps.

crossfire said:

Very nice projects. The descent rates on chutes seem to be very slow. D

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The statistics shown from the Altus Metrum Easy Mini are reflective of the events it has control over. On the first flight the main deployed early (1600 feet, not 800 as programmed) so the time under drogue is much longer & slower which is why it reported as 25 ft/s. When it was actually under the drogue it was doing around 50ft/s. The stats reported for the main descent rate are accurate for that flight at 14 ft/s.

For second flight, the drogue reported (correctly) that it's average decent rate was at 45 ft/s (graph shows osciallting between 58 & 39 ft/s) and the main was listed as 25 ft/s (due to fact main was slow opening, event triggered at 800', chute fully inflated at 450'. The graph shows that it was falling at 16fps once fully open.

And yes, it is slightly overchuted using the 5' BAMA rotosail, but it looks so damn good...

I’m a kiwi from Hawkes Bay, so not so keen on XXXX. I am however very keen on Coffee, so will take you up on that offer!