My first High Power rocket

[havoc821]

After many different designs I have finally chosen the final design for my next big project. My first HIGH POWER rocket!!! All of this started at the October HARA (Huntsville Area Rocketry Association) monthly launch. While I was prepping my rockets, my mom was wondering around talking with others. She found this one guy (Chuck Andrus) and stayed around him for the rest of the day. Well, Chuck contacted my mom at work one day and said he had some old rocket parts to give me that he would never use and wanted them put to good use. My mom went and got the parts and brought them home for me. I was shocked! The whole back seat of my mom’s car was filled up with rocket stuff! There was two 4inch diameter tubes that were 36inches long, a 4inch diameter nosecone, about 100ft total of tubular nylon, a LOC 4” prototype V-2, various tubes, 54-29mm motor adapters, 2 part expandable foam, and the list goes on. I’m sure there was close to $200 or more worth of stuff. Well my mom and Chuck are now dating and Chuck has helped me overcome some problems I’ve had with the design. The rocket is 4inches in diameter, 9feet tall, and will weigh probably 10-12lbs finished without motor. It will have a permanent 3inch motor tube and I will make adapters so I can fly it on 54 and 38mm motors. The rocket will use dual deployment, drogue at apogee, main at 1000-600feet depending on motor choice, and with have 6 fins. The fins will be cut out of 1/8” plywood (not through the wall) but once attached to rocket, the will get a fiberglass coating. I know, the fins aren’t all that thick, but with the fiberglass on them, they should hold up pretty good and I don’t plan on fly this rocket on M motors although it is capable of flying on Ms!!!!! I will probably launch the rocket on an I211 for its first flight unless I have some extra money then I will fly it on a J. I know, I know, right now you are thinking how can I do this since I am only 15 and can’t even attempt to get certified. I will just hand my rocket and the money for the motor to someone who is certified and have them press the button. I have checked with the president of the rocket group that I launch with and he said that I’m allowed to do that. So, as soon as I get over my flu I will sand the bulkplates for a good fit inside the couplers and airframe tubing. Chuck had some spare aluminum centering rings that he gave me along with and extra 4inch tube and a 3inch motor tube. At the bottom, I have attached a rocksim picture. As soon as I get all the parts sanded cut, etc, I will lay them out and take some pictures and post them soon. I hope to be over my flu by the beginning of this week so hopefully around mid-week I can have pictures posted. I’m really excited about this rocket and can’t wait to start.

 

[havoc821]

Here is the 3D picture of the rocket.

 

[loopy]

Wow! Your mom must have made quite an impression - can I borrow her for my next launch? I need some parts...lol

Anyway - congratulations on the haul, and good luck with the rocket. Any reason you're not going through the wall with the fins? I would strongly suggest it. They will hold up much nicer on the landings, and with the bigger motors... I like the six fin design, though, and I can't wait to see it built!

 

[havoc821]

Yeah, it was really nice of Chuck to give me that stuff, he just happen to see me and thought I could use the parts that he would never use. He didn't do this to get "bonus points" he just did it out of kindness.

I would do through the wall, but I cannot slot tubes good at all and I don't have the right tools for it anyways. I like to "oversize" my chutes, so landing might not be too much of a problem and I will put a lot of fiberglass on the fin area of the rocket. Besides there wouldn't be much of a fin going into the rocket, only about 1/2 an inch because the rocket has a 3 inch motor mount in a 4 inch tube. I chose a bigger mount because you can always adapt down and you never know, I might get a little power hungry. I finally got over the flu so I will try to go to my dad's house on Wednesday and sand the bulkplates and cut the fins out. Then I will start construction on the rocket very soon. Pictures may take a little longer to get because my digital camera also happened to be the on I used for my onboard videos and well, the delay I chose was a LOT longer than I thought and now my camera is um.....uh...... banged up a good bit. The shutter button that is soldered onto the circuit board broke off and the plastic body of the camera, the top part, is broken. I might take a bunch of pictures on film and have them put the pictures on a CD when I get them developed. I will keep everybody posted once I make some progress.

 

[Ryan S.]

interesting, all you need is a razor to slot tubes. It is a great idea. put the fins in through the slots then pour some expanding foam down there it will strengthen your rocket alot.

good luck man! sounds like an awsome project

 

[gerbs4me]

man you got lots of goodies
sounds like a awesome rocket

 

[havoc821]

Razor to slot phenolic tubes?!?!?! Are you crazy?! That might work for Estes and LOC tubing but I wouldn't think phenolic. I have never tried but I already have the fins drawn on the wood and there is no room left to make the extensions that go "through" the wall. Even if I did slot it with a razor, then I would have to cut it many times to get the right thickness because I don't have super thin fiberglass fins, I have 1/8" playwood fins that are fiberglass reinforced. Anyways, Chuck was very nice and took my injured camera to his work and fixed it for me. I can take pictures now, but as soon as I get all the fins cut and the threaded rods cut and sand the bulkplates, I will take pictures and then start the project. I am finally completely over the flu, so I will try to have something built by the end of this weekend. Thanks for all the input and keep it coming. I like when people reply, especially when they are good comments. Thanks guys and I will keep you posted.

 

[MarkABrown]

Originally posted by havoc821
Razor to slot phenolic tubes?!?!?! Are you crazy?! That might work for Estes and LOC tubing but I wouldn't think phenolic.

Yes, you can use a razor or x-acto knife on phenolic tubing. It just takes a little patience. You draw your lines on the airframe and score it with the knife. Then you repeatedly score the line deeper and deeper until you break through. Through-the-wall fins will make your rocket much more durable.

 

[lalligood]

Originally posted by MarkABrown
Through-the-wall fins will make your rocket much more durable.

On top of the extra durability as mentioned by Mark, the effort of slotting your own tubes will only multiply your satifaction, pride, & sense of accomplishment when the rocket is completed. I had the same kind of reluctance to spend the time to slot the tubes for my BSD Thor I built a couple months ago. My reluctance quickly disappeared after I started the process. Let me tell you, I've never been so proud of my handiwork as I was with my finished Thor. That I learned a new technique & skill only makes it that much sweeter!

I say GO FOR IT!

 

[firemanup]

You've always got a little room for sloppyness when slotting, as your fillets will cover up alot of imperfections in the process anyway...

 

[havoc821]

FINE!!!!!! I guess a 1/2 inch off my fins won't kill me. I guess I can be an impatient person, but I admit defeat and I will take the time to slot the tube and do TTW. I did slot a phenolic tube once. I put a small drill bit in my dad's drill press and slid the tube into the drill bit and used the side of the bit to cut the tube. It took a while and I broke a bit but it didn't look too bad. I will try the box cutter and cut the tubes. Thanks for the advice and suggestions.

 

[n3tjm]

Use a drill bit, and drill a series of holes along the line where the slot will be... then use a razor saw and cut out the spaces between the holes. Have the slots start at the end of the tube, and end at a hole just ahead of the fin. Then build the motor mount with the fins cemented to the motor mount. This will make you the fin can...

 

[Ryan S.]

and then before you put the aft centering ring in throw some expanding foam in the Gap. It will make your rocket indestructable.....well not exactly but alot stronger

 

[n3tjm]

With the technique I use, the rear centering ring is already glued to the motor tube... the fins are wedged between two centering rings, and the motor tube. I usually add strips of fiberglass for extra strength. Make sure you sand the gloss off the bodytube wherever the glass is placed...

 

[havoc821]

I already have sanded the gloss off the tubes and will probably sand the fin area again just to be on the safe side. I am going to try and use a box cutter for the slots and if that doesn't work, I may try to use my dad's jigsaw. It isn't the tabletop kind, It is the kind that you hold. I would really rather use the jigsaw because it would cut better and it cuts thicker, so I wouldn't have to make so many passes to get the right thickness. I am going to epoxy or JB Weld (I like this stuff because it has the strength of epoxy without the brittleness) the foward centering ring on the MMT. Then I will epoxy the fins on the MMT and slide into rocket and apply external fillets. Then I will fill with expandable foam and the I will glue the rear centering ring on. I didn't get to go to my dad's today to sand the stuff. But........he said he will give me his sander because he is getting a new one, so this will be great because I can really use it and not have to bug him all the time about wanting to use it. I will try to have the fins cut and bulkplates sanded tommorrow and post pictures. I am also might be going to my friend's house tommorrow to work on the Team America rocket, so while we wait for stuff to dry, I can work on this rocket. More info and stuff later. Thanks for the replies and keep them coming.

 

[havoc821]

By the way, where can I get fiberglass strips/cloth without spending a lot? Thanks.

 

[Rocketmaniac]

Another idea about making a stronger aft section, is to extend the fin slots all the way to the end of the body tube...... Then put the centering rings on the motor tube and "tack" the fins to the motor tube....... Remove the fins and motor tube by sliding it out and then epoxy everything real good........

This is what I did with my LOC Expeditor........Here's the thread


https://www.rocketryforum.com/showthread.php?s=&threadid=4441&perpage=20&pagenumber=2

 

[havoc821]

rocketmaniac,

I think I finally understood what you said. That is pretty much the same thing I did with my Eye in the Sky2. I slotted all the way to the end of the tube. Epoxied the centering rings to the MMT, the epoxied the fins to the MMT and slid the whole thing into the booster airframe. I then applied external fillets and epoxied the centering rings in the booster airframe tube. I will probably do this same thing to my high power rocket and the only difference will be I will leave off the rear centering ring and fill the the tube with 2 part foam then I will glue the rear centering ring on. Thanks for all the tips and input.

 

[Ryan S.]

Originally posted by havoc821
By the way, where can I get fiberglass strips/cloth without spending a lot? Thanks.

I would go to Home depot. Their Fiberglass is okay but if you are only using strips is will be much cheaper to buy a yard because you wont have to pay for shipping. Thats where I got my first glass from. I fooled around with it for a little bit and then bought the big role of high quality stuff

 

[havoc821]

I finally got pictures but they are too big and I have to resize. I will try to post the tomorrow.

 

[havoc821]

Ok, I finally have the pictures resized and here they are. I took a bunch of my pictures and made them into one picture for my posting ease and your veiwing ease (so you don't have to open 10 different pics, instead you can open just one. In the pictures is me next to the rocket, my altimeter bay (outside and inside), and me retying the shock cord. I tied the nosecone to the wrong end and the booster to the wrong end. Silly me. Enjoy! Comments, or questions are greatly appreciated!

 

[havoc821]

Here is a bigger picture of me, the bottom of the rocket showing the aluminum centering ring, and the booster coupler tube. I will try to get more pictures later but probably not untill this weekend.

 

[havoc821]

Well, I have more of the rocket done. I have the fins tacked onto the MMT with JB Weld. I will try to go to Home Depot sometime soon and get some fiberglass cloth unless any of you know where I can get some good fiberglass cheap. Once I get the fiberglass, I will put fiberglass in the glue joint where the fins meet the MMT. After that I will glue the centering rings on except the aft centering ring. The I will slide the whole motor mount section into the rocket and glue it into place and then fill with expandable foam, the I will glue the aft centering ring in place. Next, I will put epoxy fillets on the outside where the fins meet the main body tube to get the nice curve, then I will either fiberglass tip to tip or just on the joint depending on how durable the section is once the foam is filled. If anybody has any comments on how I should do this, feel free to let me know. I am very excited about this rocket and I will plan on flying it on a 54mm J. I know, I keep changing the motor but and I211 would put the rocket barely 1000 feet and I want the rocket to go a lot higher (hopefully a mile or close to it). I was thinking about a J570 which is a 38m motor but then I have to worry about some effect (I can’t remember the name) that has to do with the amount of grains and the nozzle sizes of the fuel grains and the casing which can cause the motor to have a HUGE spike of thrust at first which will give the rocket a kick in the butt, but then I run the risk of over pressurizing and the motor exploding which needless to say wouldn’t be good. So I will play it safe and launch it on a 54mm J. I don’t know what J it will be yet. I need some help with this choice. I want a medium to long burning motor (4+ seconds), medium to high thrust and white lightning or equivalent. The rocket weighs about 8 pounds right now and that is without the fiberglass and foam. I am expecting the rocket to weigh 10 or 11 pounds finished. Any help, advice, or suggestions would be greatly appreciated. I will try to keep all of you posted as I progress.

 

[daveyfire]

I've found that as long as the fins are stiff enough to survive the speeds you're going to reach, just glassing the fillet and maybe 2" up the fin is plenty strong. Of course, if you predict flutter, glass 'em tip to tip. We had a guy in our club shred a rocket because of fin flutter, but the fins were attached with just 1" of glass going up onto the fin root and down onto the body tube. When I took the airframe off the rocket (he gave me the booster -- LOTS of free 0.093" G10!), the fins were cracked from the stress along the joint where the fiberglass was. But they were still on there plenty strong!

HTH.

 

[RocketboyG80]

Havoc, did you check the prices at www.uscomposites.com? I am not sure how much fiberglass costs at HD so I couldn't compare.

 

[Ryan S.]

First, that thing looks awesome. Very good looking, I must say I really like it your altimeter bay looks like it was built great as well.

As for US composites, you can buy glass from them but if you only need a yard (thats how much they sell at HD) it might end up being a hassle because you will pay for shipping as well as the fact that you need to wait foor it to come. If you need alot of glass go for US.

Keep is updated on the flight that thing looks awesome

 

[havoc821]

I don't know anything about fiberglass or what kind to get. Is it better to have tighter woven fiberglass or the kind that isn't woven as tightly? I don't know if I will have fin flutter. I hope not. Just to be on the safe side, I might glass tip to tip just to be safe. Is 15min epoxy ok to use to lay fiberglass or do I need a longer curing kind? Thanks for the comments on my altimeter bay. It turned out really good. The only thing I am going to change about it is the mounting board. I am going to get another piece of wood and some more brass tubing and re do the board. I rushed it with the JB weld and made a mess of it. I got and RRC2X 25K for Christmas now I have my altimeter!!!!!! I still need some help with the motor selection. Refer to earlier post about the kind of motor I want. I don't want to spend more that $75 for the motor. Well, when I get more done, I will post some pics. Thanks everybody!

 

[Ryan S.]

you could use 15 minute. For small jobs I used to use the 2 ton stuff that came in the syringe. That worked good and seemed to strengthen the fins alot. Now I use the US composites stuff. If you see yourself using lots of fiberglass in the future, or lots of epoxy you could make an order to US composites, get some epoxy and glass.

I would go with a Pro38 motor. they are expensive but easy to use, a good way to start otherwise go for AT. AMWs cases are expensive but the J loads are under $75 and really nice

 

[havoc821]

ryan,

Thanks for the help, but I won't worry about the casings because I won't have to purchase them because I can't have anything to do with the motor, so I guess what I'm asking is what specific motor or reload I should choose instead of what brand. I will have to wait untill I get back to my house to run some simulations but I just might go with a 38mm J350. Does anybody have an comments about this motor, good or bad, or is there another white lightning J that provides a good amount of thrust without going over budget on cost? If worst comes to worst, I just might go back down and fly it on an I211 or another big I motor. I just need to run more simulations. Thanks for the help guys.

 

[havoc821]

I went to Pro38's website and I liked the thrust curves for the J360. What can you all tell me about this motor? How much does it cost, number of grains and where to get it and what type of propellent is it (Ex: White lightning). Thanks