Average Building Skills, Off-The Shelf Components

[SMR]

Hi All, I had an idea for a rocketry challenge. The goal would be to launch a rocket to 100,000 feet with the limit of using LOC Precision-style parts such as cardboard tubes and plywood fins. No fiberglass/carbon and minimal metal parts allowed. Bolts for the electronics bay and motor retention would be okay. Another rule would be Tripoli certified motors.
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Cheers, Alex

FWIW, the original concept is a point worth exploring. What IS the limit for the majority of us, with average building skills and off-the-shelf components.

This segues nicely to introduce a project I have been quietly working on in the background for the last decade or so. It started with Jackson L. questioning if we could reach the stratosphere. (We can). Never came up with a good name, since any acronyms using the project limitations somehow always included a distasteful Jack London reference. As we all know, I work really slowly, since deadlines force errors and I am basically lazy.

Ramblings...

The idea of staging an N5800 to an O3400 was intriguing, but unfortunately it (slightly) bumps over the 40,960 Ns limit for Class 2 rockets. But the project started with that concept - a two stage rocket with commercial motors. Half the atmosphere is below 18,000', 3/4 of it is below 35,000'. So, generally, if we could get above most of the air molecules, drag is less of a factor. The third stage grew from that.

Min diameter for staging doesn't work for me. I know, people have had good success with it, but my average building skills prefer through-the-wall fins to have a viable tang (1). And which leaves internal space to route ignition circuitry (2). (No head-end ignition for me, either.) And coupling the stages is easier when the aft closure isn't the widest part of the rocket (3).

I tend to build heavy, (the average building skills part), which is probably the biggest limiting factor. I am sure with off the shelf components, 35,000' can be easily reached, with the possibility (and goal) of 10 miles high (52,800').

Progress to date (photos to follow) ...

This is a long-term project, expected launch at least 2 years down the road, so there won't be daily updates until we get closer to launch. Currently (no plan survives contact) we sit with a 6"/98mm booster (75% complete), a 5.5"/98mm second (waiting on rings from Tim), and a 3"/54mm third (95%). My 1st Gen Kate fits in the 3" nose. The 6"-to-5.5" ISC (50%) and the 5.5"-to-3" ISC (80%) are currently on the workbench. Some kit bashing but mostly assembled from commercial components. My fins from 3/16" G-10 stock. Slow road.

The stages will be flown individually, then in combo's of two, and finally in the full stack with smaller motors, working the way up the motor chain as launch opportunities evolve.

 

[GalantVR41062]

Looking forward to pictures and simulations. It's a long read but Jim posted a great thread: https://www.rocketryforum.com/threads/i-could-use-just-a-little-guidance.122042/page-30#post-2342796

A lot of other good staging talks in that part of the forum.

Loki has a few longer 54mm motors in the K and L range, not as easy to light for upper stages but the L2050W is a must fly some day for me.

 

[SMR]

Thanks, good reference material. I will definitely read through it, multiple times so it sinks in.. I think I have time!

My last big staged rocket was the SeaHawk. 7.5"/98mm cardboard and plywood booster to a 5.5"/75mm G-10 sustainer. Flew perfectly straight but was designed more for looks (upscaled Estes kit) than altitude. Intentionally staged low. This quote from that thread is still relevant.

It is interesting to note that the L3150 provided over 40% of the total Impulse of the stack, but contributed only 10% of the altitude. Granted, it carried twice the weight. With a little more data, one could probably do a better job optimizing the motor selection (and rocket design) to make a more efficient use of the fuel.

 

[bjphoenix]

This segues nicely to introduce a project I have been quietly working on in the background

Are you still talking about plywood and cardboard?
(Deleted my post, Sorry, I didn't see the other thread first.)

 

[SMR]

Nope. Alex was advocating plywood and cardboard in his thread, but I include anything "off-the-shelf" in mine, which includes (and in this case requires) composites. The N5800 has been earmarked for this since day one, but knowing how punishing that motor can be just by itself ruled out cardboard early on. And while carbon fiber would be preferential, it still has to be done on a realistic budget. (Which is why it has been spaced out over such a long time span). Some rings are plywood, which IMHO hold screws better, but most everything else is just plain fiberglass. The booster is 6" from filament wound glass tubes I has leftover from another project. The 5.5" second stage is also glass, originally started as a spare / replacement upper for my Seahawk, so I could fly 98mm motors in it on a higher waiver than we can get near O'Hare. (The original Seahawk upper is 75mm). 3rd stage and ISC were kitbashed from the Madcow Nike / Tomahawk kit, with a nose cone supplied by good friend and fellow QCRC member Chuck H, which I modified to fit Kate (GPS w/ downlink) to get real-time altitude reporting and help me find her afterwards. The fins on all stages come from 3/16" or 1/8" sheet G-10. So literally everything on this project is or was commercially available, and it is just a matter of glueing it all together. And verifying simulations via progressive test flights. No special tools or construction skills required. It will be more of a "process" thread than a "build" thread.