Star Orbiter G80T...Supersonic?

Nytrunner said:

How much does it weigh?

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It’s 108.6 grams/3.8 oz right now. That’s after all epoxy/glues and structural components. Which sounds about right because sim says 240g with the engine and electronics.

Cool, now make it happen and don't forget to post results, good, bad or anywhere in between. Personally I think it is possible, may just take more than one iteration but seeing as how inexpensive they are....

Wallace said:

Cool, now make it happen and don't forget to post results, good, bad or anywhere in between. Personally I think it is possible, may just take more than one iteration but seeing as how inexpensive they are....

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So I launched a couple months back and everything went ok except for the fact it landed in the only couple of trees for 3sq mi and it’s too thick on the ground to see where it is, and even if I could see, it would be too high to get it down. I’m reordering everything Monday or Tuesday to try again. As far as I know, the rocket was in tact when I saw it through my binoculars but I could be wrong as it was pretty far away. I’m going to a bigger launch site next time and I’m going to use a longer launch rod. I think the rocket was too unstable when it left the launch rod...I shortened my traditional 5’ to 3’ to avoid whip...I think the ideal launch rod length I found plugging numbers in OpenRocket was around 4-4.5’. I did have retrieval methods in the rocket it was just unlucky that it landed in those trees...it was open space for about a mile and a half except for those. Any tips for the next launch would be greatly appreciated.
And I am planning to launch by late October...any idea how colder air will affect the rocket and the flight?

Rod=no good. Tower or at least fly away guides. A clean launch from a rod is rare..

Even a rail w/buttons would at least be more consistent.

Wallace said:

Even a rail w/buttons would at least be more consistent.

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I was thinking about fly aways...with how fast this rocket is accelerating off the launch pad, do you think it would be affected by the fly aways?

Personally not a fan, they WILL hit something when they come off. Consider 'em the "easiest (though not cheapest) route. If you have or have access to a 3d printer there are Stl. files online to print your own. Someone was working on hollow plastic buttons with a cutter at the top of the rail. Seemed interesting, but still gonna have an affect. Probably best to cobble a simple tower, should have least amount of impact and your rocket can be clean/clear of any guidance bits for super duper sonic speediness...

I second some sort of tower. A fly away guide on a rocket that light will be a significant unpredictable mass. The mass will (slightly) impact the acceleration off the pad. More importantly pulling that many G’s will increase the probability of hitting a fin. Larger rockets can power through such an event. The fly away is a much smaller portion of the total launch mass.

Some plywood scraps and conduit will work if you don't want to throw $ at it...

retortec said:

I second some sort of tower. A fly away guide on a rocket that light will be a significant unpredictable mass. The mass will (slightly) impact the acceleration off the pad. More importantly pulling that many G’s will increase the probability of hitting a fin. Larger rockets can power through such an event. The fly away is a much smaller portion of the total launch mass.

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Noted.

Wallace said:

Some plywood scraps and conduit will work if you don't want to throw $ at it...

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Sounds like something I could manage.

For future reference, what’s the best way to shop for a tower?....I’m kinda new to that concept in terms of model rocketry. I’ve done searches and can’t find anything except for Apogee’s tower.

From my 1965 Handbook of Model Rocketry. First tower I built from 1/8" plywood. Towers get really expensive. Best bet is to do some searches on the fourm for ideas. Fined a design in your budget and skill level. I bet it will be far better than what you could buy for the same price.

retortec said:

View attachment 395302 From my 1965 Handbook of Model Rocketry. First tower I built from 1/8" plywood.

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That’s super helpful!!! Thank you!!!

How would I go about determining the height? Sims?

Use Open Rocket or Rocksim to determine stability at launch. The length of the "launch rod" can be entered in to the simulation. Small Mach Busters have less overall stability as a trade off to lower the drag. I have always used a bit longer tower than needed for such high speed launches to assure stability. If your sims show good stability a shorter tower will work. I have seen effective towers as short as 1.5 the length of the rocket.

Do you have, have access to,or know someone with a 3d printer? https://www.thingiverse.com/thing:2538353 Would probably be the easiest although not cheapest way. If not, I'd be willing to print and ship it for free if you pick up material and shipping costs...All I'd want in return is supersonic data

Or, there's always this cheap(er) but not bett(er) option... https://www.thingiverse.com/thing:3706482 Same offer stands...

Wallace said:

Do you have, have access to,or know someone with a 3d printer? https://www.thingiverse.com/thing:2538353 Would probably be the easiest although not cheapest way. If not, I'd be willing to print and ship it for free if you pick up material and shipping costs...All I'd want in return is supersonic data

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Yes i do have access to a 3D printer!


Thank you for the links!

Cool. It's all downhill from there...

Wallace said:

Cool. It's all downhill from there...

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So I kinda skipped the 3D printed part and put this wild contraption together...

Figured this would do the job. We’re gonna test it this week with a small E engine and see what it does. Seems to fit well.

I like it! Nothing better than something you created yourself. Just make sure you strap it down well. Ratchet straps and stakes are your friend.

And, consider rotating those angle irons (aluminums?) 180 degrees? Less surface contact = less friction =

I like it. Be sure the rocket slides freely the entire length of your rails. A little rattle is ok. All the edges that touch the airframe should be smooth and free of defects. I usually go for a 400 grit sand paper in the end. A little car wax and buff finish it off.

retortec said:

I like it. Be sure the rocket slides freely the entire length of your rails. A little rattle is ok. All the edges that touch the airframe should be smooth and free of defects. I usually go for a 400 grit sand paper in the end. A little car wax and buff finish it off.

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Thank you!!

I agree with Wallace. Reducing the number of contact points will enhance the efficiency of the tower. Either way be sure you are using the air frame and not the fins for contact points.

retortec said:

I agree with Wallace. Reducing the number of contact points will enhance the efficiency of the tower. Either way be sure you are using the air frame and not the fins for contact points.

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Yeah...understood. Thank you!

Super cool. Now let's see some data..

Alright so I think the group of students I’ve worked with on the project are ready and we’re launching today at ESL-255...it’s a 3 hour drive for us so hopefully it’ll be worth it and we can find it...unlike the last time.


Hope to see some of y’all there. Have a good day, guys...and thank you so much for your help!!

Sorry I'm a little late to the party here... An idea... to help with the recovery of the electronics should the rocket shred, may I suggest putting in a long, pleated, mylar streamer in the payload bay attached to the sled. Might make finding the expensive small parts easier to find.

[EDIT] I'm not saying that the streamer should be the method of recovering the payload bay section. It should be inside the payload bay in the event that whatever causes the shred tears the payload section open, scattering the components like the prizes from a pinata.

Now I'm working on this kit's 'lil sister' (the Hobby Lobby exclusive kit (The Vapor)). So much of the material needed to sim this kit is actually already done. If someone can get me a scan of the fins and decals (along with a ruler for scale), I could whip up a sim for you.

K'Tesh said:

Sorry I'm a little late to the party here... An idea... to help with the recovery of the electronics should the rocket shred, may I suggest putting in a long, pleated, mylar in the payload bay attached to the sled. Might make finding the expensive small parts easier to find.

Now I'm working on this kit's 'lil sister' (the Hobby Lobby exclusive kit (The Vapor)). So much of the material needed to sim this kit is actually already done. If someone can get me a scan of the fins and decals (along with a ruler for scale), I could whip up a sim for you.

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While I do like the idea, I can't agree with the concept. Yup, lost more small stuff than I'd like to remember, but it's technically preparing to fail..

Wallace said:

While I do like the idea, I can't agree with the concept. Yup, lost more small stuff than I'd like to remember, but it's technically preparing to fail..

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I can confirm that this is an essential failure set up in a sense. Even with all of my tracking efforts, I think the design works but the rocket goes up almost too high to keep track of, and today it went above the cloud ceiling, meaning we lost track of it and managed to lose it. It’s there somewhere but not that we could find.