7th and 8th grade first launch

[UrbanKnight]

I instructed them on building the rockets, and some of them listened carefully while others sanded the fins the wrong way, installed the fins in the wrong place, and/or packed the streamer too tightly. Still, 10 Estes Star Troopers made it up into the air.

A couple of them made straight and high flights, many of them made spirals, a few of them failed to deploy their streamers, and a 2 of them lost a fin mid flight. I'm not sure how this one got a chunk taken out of it's nose cone. Scraped the launch rod? Kickback from the ejection? Either way, with the streamer back on, how well do you think it will fly with that hunk of wood missing?

As a final note, I don't think I'm going to teach kids to build mini engine rockets again. They're harder to deal with. If I do this class next year, I'm going to stick with BT-50 size rockets. Their second rocket will be that size, so I hope it's a little easier to demonstrate and replicate.

 

[JStarStar]

Mini-engine rockets do require a bit more small-detail assembly work than BT-20 or -50 birds and some real fine motor skills and dexterity.

The first suspicion when you see a nose cone with a bite out of it is ejection charge snap-back, but the BT doesn't appear to be also dented as it would be in such a case.

Not sure how the launch rod could take a chunk of wood like that out of the nose cone, although I suppose an extreme case of rod whip could do it.

My guess might be the NC got dinged on a rock when it landed, but if that happened, you probably would have seen the wood fragment sitting right there where the rocket landed.

As far as how well the rocket would fly with the dinged nose cone, my guess is it might veer a bit toward the side with the gouge in the cone (the gouge would act as a 'scoop' and increase drag, thus the rocket would veer in that direction).

I suppose you could get some wood putty, fill in the gouge and sand it off to a nearly-smooth shape, but that would be a heck of a lot of work for a mini-engine-size rocket.

I might see if somebody else had a kit that didn't make it into the air and just see if you could scavenge a cone from another kit.

 

[UrbanKnight]

I couldn't tell you if the chunk was there or not, as the students recovered their own rocket. One other rocket did lose a fin that was never found, so we could have donor parts.

Most importantly, though, the kids had fun and by the sounds of "woah" and "awe", they could tell which rockets were performers and which weren't. Next week will tell if they take that experience to heart and apply the lessons to their next project.

 

[Sooner Boomer]

As a final note, I don't think I'm going to teach kids to build mini engine rockets again. They're harder to deal with. If I do this class next year, I'm going to stick with BT-50 size rockets. Their second rocket will be that size, so I hope it's a little easier to demonstrate and replicate.

That's a super project. Kids have so much energy and entheusiasm. Too bad Fat Boys are out of production. Those made great first/second rockets, there's not a lot that can go wrong, but supervision is needed. Here's a group I worked with.

 

[DAllen]

Fliskits Thingamajig

Much better kit and can buy them (and other Fliskits) in bulk:

https://www.fliskits.com/services/education/bulkpack.htm

Great project by the way.

 

[Marc_G]

Missing chunk almost certainly was snapback. I've seen a nearly identical gouge-out myself, and the chunk was later found INSIDE the body tube. If the NC snaps back just right, it doesn't bend the BT impact site. My Magician also suffers snapback, with ~1/2" indentations into the balsa transition, but it never bends the BT because the balsa is soft.

Neat pic, and congrats on getting the kids excited!

 

[plastic_gorilla]

Fliskits Thingamajig

Much better kit and can buy them (and other Fliskits) in bulk:

https://www.fliskits.com/services/education/bulkpack.htm

Great project by the way.

2nd on the Fliskit(s) with the Jig-Tech fins. My son and I just did a Watchamacalit. He is young to build his own (4) but he was able to get the fins together and I helped hold them. He did most of the engine mount build because all but one piece line up to ends of the engine tube. the whole kit designed to there is as little measurement as possible, but enough that you get to practice your skills and. Most of my job was reading and explaining the steps and helping with laying an even(ish) amount of glue.

So you can eliminate the spinners and the lost fins, and with the tube not being minimum diameter they can load the recovery streamer much easier.

just my :2:

 

[UrbanKnight]

Fliskits Thingamajig

Much better kit and can buy them (and other Fliskits) in bulk:

https://www.fliskits.com/services/education/bulkpack.htm

Great project by the way.

I've browsed the Fliskits site, and that kit does look like a fun one, but I want something with the standard fin design so the students can design something with the same concept and work with it in OpenRocket. These students qualify for the enrichment class by being proficient in math and English, and I'm supposed to strengthen at least one of those through the course, so they will be calculating fin surface area, CG, CP, altitude, etc.

They do seem to be a very education friendly company.

 

[UrbanKnight]

So you can eliminate the spinners and the lost fins

True, but spinners and broken parts are part of the learning experience... at least at this age. I think the low flyers and damaged rockets will encourage them to take more care when assembling the second kit.

 

[JPVegh]

I've browsed the Fliskits site, and that kit does look like a fun one, but I want something with the standard fin design so the students can design something with the same concept and work with it in OpenRocket. These students qualify for the enrichment class by being proficient in math and English, and I'm supposed to strengthen at least one of those through the course, so they will be calculating fin surface area, CG, CP, altitude, etc.

They do seem to be a very education friendly company.

Fliskits is more than an education friendly company. Jim Flis is one of the most active people I've seen on these boards as far as getting rockets into the hands of kids. His after school build sessions with the boys and girls clubs and other organizations are an example of his personal contribution to the next gen. He not only builds great kits he is a great guy.

That said if you are looking for a more standard 3FNC design I would recomend that you check out the Balsa Maching Service School Rocket. It uses 18mm motors, has slotted body tube and through the wall fins. The design is simple as is the build and the price ain't bad either.

https://www.balsamachining.com/school.pdf

 

[UrbanKnight]

Actually, through-the-wall is another thing I'm trying to avoid. At this age, they should learn to measure out fractions of a circumference, to take patience and attention to detail to align the fins with a guide, lengths along the body tube, etc.

That is a nice option for a first build or for an elementary school project if the teacher wants to go further than preassembled fins. For my class, their second rocket will be a 10-15 long BT-50 rocket with choice of one of 4 nose cones and 3 to 6 custom designed fins they will outline on balsa for me to cut. They can use a fin jig if they want to make one out of foam board, and they will get to choose 24" streamer or 6" parachute recovery. We will then award the highest altitude, the closest streamer landing, the closest chute landing, and the best looking (judged by other teachers).

I got some more pics to post tonight!

 

[skybuster]

Yeah, BT-20 can be a pain to work with especially if your fingers are on the larger size, but the mini engines are impressive! Out of curiosity, are you allowed to use 1/2A engines with your school?

 

[UrbanKnight]

Yeah, BT-20 can be a pain to work with especially if your fingers are on the larger size, but the mini engines are impressive! Out of curiosity, are you allowed to use 1/2A engines with your school?

Yes, we used 1/2A3-4 in the Star Troopers with flights reaching close to 400'*
We'll be using 1/2A6-2 in the BT-50 rockets and maybe A8-3 if I feel they won't drift too far with 6" parachutes. Our fire permit and ample field size allow A size engines, but I'd rather play it safe with a highway not too far away.

* Altitudes were calculated with homemade altitude trackers recorded by 9 different teams posted at 3 different locations for triangulation. Each location took an average, and then the 3 locations' averages were averaged.

 

[UrbanKnight]

As promised, pics.

Lift-off

This is the only shot I have of the kids without face shots.

 

[JPVegh]

Actually, through-the-wall is another thing I'm trying to avoid. At this age, they should learn to measure out fractions of a circumference, to take patience and attention to detail to align the fins with a guide, lengths along the body tube, etc.

That is a nice option for a first build or for an elementary school project if the teacher wants to go further than preassembled fins. For my class, their second rocket will be a 10-15 long BT-50 rocket with choice of one of 4 nose cones and 3 to 6 custom designed fins they will outline on balsa for me to cut. They can use a fin jig if they want to make one out of foam board, and they will get to choose 24" streamer or 6" parachute recovery. We will then award the highest altitude, the closest streamer landing, the closest chute landing, and the best looking (judged by other teachers).

I got some more pics to post tonight!

Ah, it sounds like your talking about scratch building. There's nothing wrong with that idea. Are you using theodolites to determine altitude reached?

 

[UrbanKnight]

Ah, it sounds like your talking about scratch building.

Yep. They will start with a Surefire X-13 kit (no instructions and just blank balsa stock), and will be offered to change the stock nose cone with one of 3 others (from the Estes pack or Surefire #2) and will be allowed to swap the streamer for a 6" Estes chute. Most of these choices will be made while using OpenRocket before they start making physical drawings and templates. I hate to admit it, but I'm having more fun teaching this than I do teaching my normal subject (band and orchestra).

Are you using theodolites to determine altitude reached?

I downloaded this template, but used foam board and Slurpee straws. Considering some of the variances between 2 people in the same basic spot and the crudeness of the devices, we could easily be off by 50 or 100 feet.

 

[edwinshap1]

in the second picture i noticed you set up a perimeter, and none of them technically broke it since the tape got pushed inward

Glad to hear your students had a blast. Also, concerning the bad measurments due to homemade trackers, Estes does make hand trackers that give an angle, and based on the distance to the pad, the user has to calculate the max altitude (there is a trigger that you release when the rocket hits apogee).Alti-trak. I think it would be a good lesson to have one of these, and then the students could make their own. Then as a group everyone could find out how accurate their home made tracker is compared to a prebuilt one

Also, i know it's definitely too late to have a field trip in mid november (i spent 12 years in LAUSD), but if you want to get your students really psyched about rocketry, and where it can lead them, i'd highly recommend a ROC launch link here. Not only will they see rockets larger than they are, they'll also learn about rocket science. What i mean is that if you ask anybody about a rocket they have sitting in front of their camp/car, you'll get a lecture on how it's built, how it flys, and how they expect it to perform on the motor they're about to put it in...i'm guilty of that hehe

 

[GDJ]

Yes, we used 1/2A3-4 in the Star Troopers with flights reaching close to 400'*
We'll be using 1/2A6-2 in the BT-50 rockets and maybe A8-3 if I feel they won't drift too far with 6" parachutes. Our fire permit and ample field size allow A size engines, but I'd rather play it safe with a highway not too far away.

* Altitudes were calculated with homemade altitude trackers recorded by 9 different teams posted at 3 different locations for triangulation. Each location took an average, and then the 3 locations' averages were averaged.

Very cool! Rockets look great!

For the BT-50 tube rockets, I would go with the A3-4T engine. The rocket will have a little bit lower speed, but it will still go the height due to a longer burn. I find that works well to keep parts on the rocket. Also that engine will do very well in the BT-20 tube rockets.

 

[UrbanKnight]

in the second picture i noticed you set up a perimeter, and none of them technically broke it since the tape got pushed inward

I put the tape at 16 feet, but maybe I need to reconsider my strategy and build a wall or something.