Tubby

[gagreen]

I picked this rocket up off of the yard sale section from Scott at K&S Rockets. Its 69" tall, 2.56" dia, 38mm mmt, and has k&s's av bay. My first kands rocket was one of the upscaled bbz's, my intention was to use it to learn about flying dd but after i got it built and in primer i liked it so much i decided to go with something different to suffer the abuse of a learning curve. This rocket with its tube fins and simple looks fit the bill. This being my first tube rocket i figured i should make a thread to post up those quick questions about assembly when i run into them.

I have done some searching around on the forum already and found a king kraken build where the builder used dowels to add surface area to the fin attachment i have some small dowels so i may end up using this method as well. I am not really sure if i should glass this rocket or not. Tube finned should keep it on the slower end so I believe the body tube will be alright. The tube fins i may end up doing as a few have mentioned on here just glass the interior of the fins but is this really necessary? I dont want to overbuild but also dont want to get started and realize i messed up and should have done something different. I dont plan on flying this with anything over H's.

So I want to open up the forum to suggestions from the folks who have flown these types of rockets before and hear your thoughts or experiences with tube fins.

Here is the kit out of the box with the av bay assembled. Not pictured is the ksr5 chute and a streamer i ordered separately. The alt ill be using is the adept 22.

 

[dixontj93060]

If I remember right, this rocket has 6 tube fins evenly spaced around the main body tube. In this case, you have each fin contacting and supporting the adjacent fins on either side so I doubt if you need the dowels to add surface area/support.

 

[gagreen]

Yeah they all have 3 points of contact 2 points to the adjacent fins and 1 to the bt

 

[Buckaroo]

Tube fins are great! I built one very similar to this, actually an upscale of my Estes Super Neon, and ended up getting my L2 with it.

As folks have already pointed out, since this is a "standard" tube fin where the tubes are bonded to each other as well as the main BT, you shouldn't need to do anything special with the joint like Tim did with his King Kraken build. As far as reinforcing the tube fins; I glassed the inside of mine to try and cut down on landing damage, and also because I wanted to try my hand at glassing. As an easier alternative you could buy a couple of extra couplers and glue a couple inches worth into the bottom of each tube fin. the build thread for mine is here: https://www.rocketryforum.com/showthread.php?t=8436

If you use RocSim to predict the performance of your birds then be sure to use the Cd override tab, and input something around 1.45 to get a better idea of what to expect. I'm willing to bet you'll end up flying more "I" inpule motors than anything else... The ATI284W is a personal fave

I enjoy flying mine so much I have a 4" version with a 54mm motor mount under construction.

Have Fun :horse:

 

[gagreen]

i like the coupler idea in the bottom of the fins i think im going to use that. I am slowly working my way into new to me techniques i think ill save fiberglassing for the solar warrior... I am a bit of a kands addict. Ill get some pics up as i progress through it.

 

[o1d_dude]

You might try cutting the couplers in half lengthwise as the landing dings will be on the outside edge of the tube fins. Basically, you'll be making a half-doubler that you epoxy inside the tube fin. Note the location of the half-doublers in the third photo.

Larry Brand has experimented with sandwiching a layer of fiberglass cloth between the fin and half-doubler creating a composite tube fin. I've have not yet tried that. He's also made tube fins from phenolic tubing with a layer of epoxy and fiberglass cloth on the outside.

Here's a set of fins for one of my tube birds illustrating what I mean about half-doublers. Just don't add the half-doublers until you've attached the tube fins to the airframe as they can put the fins slightly out of round. No problem if you add them after the fins are on the airframe.

 

[gagreen]

couldnt resist a mach up shot while the mmt was drying. gotta excuse the disaster zone that is my workbench.

 

[gagreen]

Fins are all epoxied on, i left out the dowels as it is already a fairly heavy build. Thank you for your inputs on that you all saved me some time. I did what im calling a "drip" fillet on the fins external joints so it should stand up pretty well to just about anything that i am willing to fly it on.

 

[gagreen]

Laid down 2 coats of primer tonight ill get pics up tomorrow after i get the base color on

 

[stickershock23]

looking good So far....

Watch your mailbox... somethings on it's way to you!!

 

[gagreen]

Sweet. I decided not to go with a standard straight line color transition so i went to my box of "trash". I keep all the backing from my stickershock orders or other vinyl decals i have collected (i believe this backing came from a red arrow sticker), i think its the backing, its the waxy paper that goes on the business side of the vinyls not the tacky transfer side. Anyway i cut a few lengths out at the circumference of the body tube and layered on some blue masking tape. Doing this allowed me to sit down with my hobby knife, a pen, and the random shaped items i keep on my work bench. I hope this idea works lol but discovery of these little ideas keep the hobby fresh for me. If this works it will save me a little money and time when masking if it fails... i can always get more paint :lol:

It could be done better with wider masking tape but I didnt feel like a run to a hardware store at 8pm lol Pics of the paint job will be up tomorrow but no rocket is complete until it gets its stickershock therapy.

 

[stickershock23]

Thats way cool.

Just a note. if you design your pattern in AI you can send it to me and I'll make a paint mask out of it too. although you look like you are doing fine with the tape and scraps!

I'll even sell paint mask vinyl by the foot!

can't wait to see it with paint on it..

 

[gagreen]

Thats way cool.

Just a note. if you design your pattern in AI you can send it to me and I'll make a paint mask out of it too. although you look like you are doing fine with the tape and scraps!

I'll even sell paint mask vinyl by the foot!

can't wait to see it with paint on it..

Been tinkering in ai with masks but i havent got it down yet. my eventual goal is to get to a point with the software that i can just send you the file, but i tend to fly by the seam of my pants when i get into painting so i use this method for the paint schemes that i dont really have a plan going in. I would be willing to bet that for larger masking jobs getting it by the foot would be much easier on the wallet than layering this expensive blue tape and not to mention the time saved by not having to sit and layer my own sheet with tape. Ill keep that in mind for my next order.

 

[gagreen]

last coat of color is on it just waiting for some stickers and then clear coat.

 

[gagreen]

forgot the picture. the color is a mopar green with a dark cherry candy. The picture looks black i guess its one of those colors you need to see in person or i need to actually set up good lighting with my real camera lol. the monotony of the paint scheme will break up with the decals i custom order from mark at stickershock.

 

[gagreen]

Stickershock came through again. The decal is kind of hard to see the cherry pearl came out really dark compared to what i had hoped so i may end up brushing some silver around the decal and make it stand out. And o how the flash shows all the spots that i got a little light with the rattle cans lol. I am thinking about "aging" the tubes a little more and work a little black in with a rag once i get the nerve to try something that rash lol.