Secret Santa Christmas In July 2022

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again, thanks!

I got a bamboo desk caddy, and 3 Excel Hobby knives! The desk caddy is too nice for my hobby table, and will likely find its way to my office (to show off ot my co workers! it is really nice! )

again, super nice & generous!



Any pics of the desk caddy?
Good morning gang and Happy Belated 4th of July!!
I hope everyone still has all their fingers and toes and got to see some amazing pyrotechnic displays last night!

THANK YOU Secret Santa for the really cool gift.

Squirrel Works Arapaho-E (Click image to enlarge)
SS-CIJ 22'-Small.jpg

I love this rocket. Before I build it, I will be taking all kinds of measurements for a 3" upscale I've had on the back burner since the dawn of time.... :p
that is a generous Santa!! Gave you some salt & pepper shakers & spices too!!

what's' teh one that's flipped over? 2nd form teh left..
It is a Flip Flyer! The other rocket is a Rocketarium “Maxtermind”!





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Thank you very much to my SS for the new crane scale! I’m just wrapping up a set of designs and prints so this is perfect timing to start some stress testing.

I have been wondering what you use that for ? All I can think of is like Recovery Harness or Links testing. Are there more applications ?
I have been wondering what you use that for ? All I can think of is like Recovery Harness or Links testing. Are there more applications ?

Those are both good uses and there are others!

I think there tends to be two types of building, light and heavy. The latter tends to be more common from what I have seen and is your typical toss on all the epoxy and glass you can handle. The kind of rocket that can largely survive a failed recovery. I tend to build on the lighter side and as a result need to plan a bit more and make sure my margins are good enough for the intended flight. More of a speciality built instead of a fly any motor rocket.

For my current project, I am working towards my L2 and intend on flying it on an almost fully 3d printed airframe (excluding hardware) with the objective of hitting 10km and mach 1. This presents me with a few primary areas of concern and use cases for the scale:

1. Losing a fin at liftoff or due to fin flutter is never a good day. I have seen individuals stand on their fin can as a means to test the fins for strength but I am a bit heavy for that and building to hold my weight would be over kill. With the scale I can print the fin can and an attachment to allow me to hang the scale from the fin tip. From there I will increase the weight until the fin breaks. This will be tested in 2 directions, one with the rocket vertical like take off and a second time with the rocket horizontal to help understand fin flutter. With known failure points I can verify whether or not it will meet the flight requirements or not. If yes, how large is the margin and can I reduce it, if no, how much stronger do I need to make it? (I haven't made it to fins yet, Im still on the NC and laundry bay)

2. I have the full AV bay in the NC for this rocket and will need to ensure that the laundry bay between the motor mount and NC coupler can withstand the max load during flight. For this I expect it will be a mix of Euler's Buckling math and then testing it by suspending weights from the tube (think of it like hanging weights from the lid of a Pringles can that is on the can)

3. At the target apogee there could be significant horizontal movement due to the parabolic flight path of a rocket and the altitude that I am aiming for. I need to ensure that the printed layer adhesion on the NC / AV bay will be able to withstand the forces associated with initial nose cone separation and subsequent rapid deceleration.

Regarding the links testing - I recently heard of someone using soft links instead of hard links (locking carabiner) to connect everything up and it appears to be a lighter & stronger method. Might be worth a look 🤷 (example, there are others as well and I may reach out to OneBadHawk to see if they would make one out of tubular nylon that is the custom length I need to connect the NC tip to the bottom closure)

for context I've included a few pictures below:
- if anyone has any constructive feedback Im happy to accept it. If its not constructive I will unhappily accept it
- designs are completed in FreeCad, printed on a Creality v3.
- different color = different material
- different materials will be tested due to differing properties (such as higher heat resistance needed on the fins for mach)

🤦‍♂️ I knew I left a picture out.

I received a RoMech Mini Crane Scale. I haven’t started the tests yet but this says it’s rated for 660lb (I can’t imagine that I’ll need to exceed that). I like that it’s digital and realistically you can use any number of attachment styles provided your connection fits through the eye holes.

Thanks for the info.

The testing I need to do is also measuring shock loads, so I need something with a high-speed updated analog output. (or) I need to use a load cell and signal conditioner into a DAQ system....

For for the price I may pickup one of these, at least I can do slow loading, and static tests. Let us know how accurate it seems to be.
If your shock load test is to measure an action this def isn’t the tool for you.

If on the other hand your looking to determine the dynamic load rating, that can be calculated from static limits since F is F. A 10N force applied dynamically is the same as a 10N force apples statically. You’re just changing the MA portion of the equation.

As far as scale, my guess is that it’s likely more correct than the bumper plates I have sitting in the garage. It’s also good to know that an eye bolt screwed into a PLA printed M6 hole will hold 15lb. That’s a starting point!


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Thank You Pap Elf for another wonderful Secret Santa experience. Neat having two Christmas Days per year !! LOL

Thank you again "Santa" for the RRC2+ Altimeter. Thank you all who participated & played along. I am going to have
to find a different place to put my snake egg incubator (Or wait a few more days till they hatch) and clear my work bench !!!
Had a little setback. Was going to go to Lowes to buy a sawhorse and a roller pan, and also was thinking about buying a Aero Pack 75mm retainer, but then my Dog got sick, and I decided not to wait till Monday and we took her to a Emergency Vet visit... and pretty much cleaned me out. So, going have to wait on more Mulah to come in later this month :D

Here is where I stand. The 5.38" stuff is in the design stage. May post here in a few days for opinions...

In the mean time I put the 1.6" HAWK together.

It only SIMs OK on very small motors. Anything F44 or bigger definitely needs nose weight. (Which I expected.) But instead....
1st, I added a payload bay to stretch it. 2nd, got the idea to make it dual deploy. (since JLCR fits so tight in1.6" diameter) ... So here is extended version with Always Ready Rocketry AV bay, 350mAH battery, and Eggtimer Quantum. (Ready to head for primer, and basic paint job.)

This should be interesting....