S2000 scratch build

[rockets2000]

Hi, I'm a new guy. I recently got back into the hobby (in a much bigger way than I thought) and after a few kits I decided to try a MP scratch build. I used Rocksim 9 for the design, and have been collecting parts and reading TRF for the past couple of months. This site is a great resource, and about 90% of the information I needed to build a MPR came from here. Thanks very much for all the info.

The rocket will be a 42" long BT-60 single stage with six trapezoidal fins. It has a 29mm main mount and a friction fit 24mm mount for D-F test flights. It will recover on a stainless steel leader attached to the main mount, 10' of woven kevlar cord, and a 36" X-Form chute.

A couple of months ago when I first started the design, I made the fins out of 1/16 basswood. I got a little over-excited and finished them while I was looking for parts and refining the design. Essentially, the rocket is built around the fins and main engine mount anyway, so I figured I might as well do something until the rest of the stuff came.

Here are some pics of what I have so far:

The parts

Dry fit just because I had to see what it would look like

Main motor mount

Steel leader attachment

I cut a notch in the fwd CR to accomodate the leader

Epoxy filletts

Dry fit of fins with main mount installed

First fin attachment

Another shot of the first fin

Any comments or suggestions are appreciated! Thanks for looking.

Sean

 

[TheAviator]

You plan on flying this on 29mm motors? You're a brave man. Your rocket is comparable in size to an Estes Stormcaster, which on an E-9 will hit in excess of 1000ft. At that altitude, it is somewhat difficult to see. On a 24mm F, it hits in excess of 1500ft, and is quite difficult to see. On a modroc G, it'll probably hit in excess of 2500-3000ft and be nigh impossible to see.

On the construction, it is looking very good. It will most likely hold up to anything you throw at it with the exception of maybe a high thrust F or G. Very nice!

 

[rockets2000]

Thanks for the comments. I hadn't really thought about losing sight of it at altitude, although I'm hoping that the 36" orange and black parachute will help me track it on the way down. I suppose I could also add weight or a payload bay w/altimeter. It's not too late to cut the upper tube short and install one. Perhaps a few body-length balsa stringers on the inside of the BT to add stiffness as well as weight and CG distrubution? Has anyone done this, and what are the chances the shock cord and chute will get hung up.

I'm also going to make a launch pad because I don't think my little Estes pad will do. I would like to use a rail system mounted to a telescope tripod I have, but I haven't found a rail yet. Where can I get a 6' piece of rail?

Keep 'em comming! I need as much help as I can get.

 

[kandsrockets]

On a rocket that light I would use a streamer for recovery. Our Weasel is about the same size and we have sent it to 3k plus and brought it back on a 7" x 92" streamer with no problems. I am getting ready to send it on a I200 and sims to 6600ft and it will be recovered with a streamer.

 

[rockets2000]

A streamer (or two) was my original intent, and I have two 4" x 48" streamers on hand. I don't have experience with streamers, so I was unsure about impact velocity, even on the simulations. Good news is I haven't bought the chute yet, so I could give it a try. Rocksim shows it going to 3200' on a F40. That's the largest engine I have simulated so far.

 

[MarkH]

Even if you did use a parachute I think a 36" would be way too big. I'd say 18 to 24" depending on the weight. 18" for around 12 ounces or less. 24 " if it's closer to a pound. Either way it will probably drift a good distance on an F or a G motor using a parachute.

 

[JAL3]

Welcome to TRF.

Your project looks like a nice one and I hope it works out well for you AND that you get it back.

 

[rockets2000]

So, can I use a 4" x 48" mylar streamer for a 12oz rocket? If not, let me know if a parachute would be better. I'm going to keep it on 24mm for quite a while. I just wanted the option of going to 29 if I thought it would handle it.

 

[TheAviator]

So, can I use a 4" x 48" mylar streamer for a 12oz rocket? If not, let me know if a parachute would be better. I'm going to keep it on 24mm for quite a while. I just wanted the option of going to 29 if I thought it would handle it.

I flew a LOC Aura on such a size streamer, and it was probably about the same weight. It came in quick, but I wouldn't say so quick as to be unsafe. I would actually suggest going to the Dollar Store and getting one of those big shiny "WELCOME HOME"/"HAPPY BIRTHDAY"/etc. streamers that are really thick mylar. They make great streamers and are about 6" x 10'. Just cut it to a length that fits nicely in the tube. The shiny mylar will show up better on a sunny day anyways.

There's no need to add an altimeter bay. With flight conditions this extreme the risk of losing it is to high for me. (You can make that decision yourself.) A cheapo high-dB siren would be a wiser investment. The CG placement should be fine on a rocket this long. If in doubt, find the CP and make sure the CG is at least 1 caliber ahead.

You can get 10-10 extruded rail from McMaster Carr. The 10-10 rail can be found here.

 

[rockets2000]

Thanks for all the advice! Unfortunately, I think I may have limited myself to LP engines after what happened yesterday, so my 29mm main engine mount is now a very strong adapter. I got the fins all glued and filleted, and decided to put the upper and lower body tubes together to get ready for sanding and paint prep. The coupler was already pretty tight without glue, so I thought I'd just use yellow glue instead of mixing up the epoxy. Well, the thin smear of yellow glue set up pretty fast, and I only got my coupler in about an inch before it would not go any further. I tried to give it one last twist and push, and that's when the lower tube began to collapse under my gorilla grip. It now has a couple of dents and minor creases just below the coupler. I smeared a layer of CA on and around the damaged area, but I think it will always be a weak point.

I guess I won't be going to the stratosphere with this rocket. If it performs well, I can see scaling it up to about 2 lbs in the future. I'll post some pics tonight.

Thanks again.

 

[Buckaroo]

Thanks for all the advice! Unfortunately, I think I may have limited myself to LP engines after what happened yesterday, so my 29mm main engine mount is now a very strong adapter. I got the fins all glued and filleted, and decided to put the upper and lower body tubes together to get ready for sanding and paint prep. The coupler was already pretty tight without glue, so I thought I'd just use yellow glue instead of mixing up the epoxy. Well, the thin smear of yellow glue set up pretty fast, and I only got my coupler in about an inch before it would not go any further. I tried to give it one last twist and push, and that's when the lower tube began to collapse under my gorilla grip. It now has a couple of dents and minor creases just below the coupler. I smeared a layer of CA on and around the damaged area, but I think it will always be a weak point.

I guess I won't be going to the stratosphere with this rocket. If it performs well, I can see scaling it up to about 2 lbs in the future. I'll post some pics tonight.

Thanks again.

Don't give up on the stratosphere so fast... Just cut the coupler out and install another one. You can either live with a rocket that's a few inches shorter (should be no problem with your design) or get another section of BT to make up the length.

 

[rockets2000]

Don't give up on the stratosphere so fast... Just cut the coupler out and install another one. You can either live with a rocket that's a few inches shorter (should be no problem with your design) or get another section of BT to make up the length.

That's a marvelous idea! I have plenty of room to cut below the damaged area and install a new coupler. I guess I was too disappointed in my bonehead mistake to think of the obvious...

 

[DAllen]

Personally, I really like your choice of a 29mm motor mount. That really opens up your options. CTI just came out with a line of Pro29 motors that are well suited for this one. The Pro29 1g case has 3 reloads:

https://www.pro38.com/products/pro29/motor.php

Not only that, but AT has the 29/60 case which has the F62 and F37 and then there is the hobby 29/40-120 case which offers everything from E to G. The 24/40 case will also work well with a plethora of D thru F motors.

If you are brave there is always the 29/360 case. :dark: I200 anyone?

You have created oodles of options for this project with that one feature. Very nice.

-Dave

 

[rockets2000]

Thanks! That's what I was going for. I wanted to design something that was simple yet a tad different. Haven't thought too much about reloads yet. I don't think I'm ready for that, but I could learn. This whole rocket is a learning experience, but as you guys all know, it sure is a blast!

 

[DAllen]

Thanks! That's what I was going for. I wanted to design something that was simple yet a tad different. Haven't thought too much about reloads yet. I don't think I'm ready for that, but I could learn. This whole rocket is a learning experience, but as you guys all know, it sure is a blast!

The best advice I can give you for reloads is get the 29/40-120 case. It has far and away the most reloads for a single case. Then grab a fellow rocketeer at a local launch if they have a minute or two to show you how to assemble the reload. The first reload will seem like it takes an hour. After that, they'll take five minutes if you take your time.

ProX reloads go even quicker.

-Dave

 

[bguffer]

I would actually suggest going to the Dollar Store and getting one of those big shiny "WELCOME HOME"/"HAPPY BIRTHDAY"/etc. streamers that are really thick mylar. They make great streamers and are about 6" x 10'. Just cut it to a length that fits nicely in the tube. The shiny mylar will show up better on a sunny day anyways.

I agree with the above. Another source of streamers (likely more expensive):
https://www.aerotechnic.com/streamers/specialty/

36" chute is way too much chute. I use a 36" chute on a 3 pound 3" diameter 5' tall rocket, and it comes down at a reasonable rate.

 

[rockets2000]

Thanks again Dave. If it survives long enough, I'll sure look into reloads. From what I hear, there is a good chance I'm going to lose it.

 

[rockets2000]

So I got some work done this week. I cut the damaged lower tube and the original upper tube just above the coupler. Then I surgically removed the coupler from both pieces and sanded the old yellow glue off. I took it down a hair more to reduce the tolerance so I wouldn't have the same problem the second time around. I used epoxy this time to take advantage of the lube effect of the wet epoxy. Both tubes went in with no difficulties. I also painted the engine mount red.

Here is the result:

Next, I went to work on the launch lugs. Since the airframe fiasco, I decided that my rocket was not as bada$$ as I thought it was, so I decided to go with a 1/4" rod instead of the rail system. I can fit a rail to my tripod launcher later if I want to. Plus I just happened to have a couple of 1/4" lugs laying around...

After reading about using dowels on the sides to add strength to round lugs, I thought I'd go one better. I took some spare balsa and cut it into strips, then sanded them into little 1" long traingles:

Then I tacked the lugs on with yellow glue. The engine casing taped to the back is for holding the rocket during painting.

I wanted to fill the lugs with something to keep glue/primer/paint from fouling the inside surface, so I came up with a quick solution. I cut a piece of standard notebook paper into two 1.5" wide strips and rolled them up tight. Then I slid them into each lug to keep stuff out:

Then I sanded the whole thing with 150 and again with 320. The rocket has had the first coat of KILZ primer to remove the spirals and minor seams. More on that to follow.

 

[DAllen]

Thanks again Dave. If it survives long enough, I'll sure look into reloads. From what I hear, there is a good chance I'm going to lose it.

Nah...I really doubt it. Unless you are going to fly a G80 or larger I really don't think you are going to loose it unless it is a low ceiling or a windy day on a small field. A G is going to put a little guy like that about 2k to 2.5k. That's easily trackable with a few people to help and maybe some tracking powder. Try a full F in it and see how it goes. You'll see that an average G will not be a problem.

My club has a guy that flies a LOC Aura on G76's all the time. It's smaller, lighter and only has 3 fins. He still has it.

-Dave

 

[TheAviator]

My club has a guy that flies a LOC Aura on G76's all the time. It's smaller, lighter and only has 3 fins. He still has it. -Dave

Dave, do you really think an Aura is lighter than this rocket?! I had one that was given to me by a friend, and the thing is a BRICK. By the looks of this one, it's made out of standard Estes/BMS tubing and therefore may actually weigh LESS than - or at the very least be comparable in weight to - the Aura.

 

[rockets2000]

Once again, my impatience got the best of me, this time with sanding. After the KILZ was applied, I waited a day and sanded it off. It went on pretty heavy, so I saw a few high spots with bubbles. I sanded and sanded with 220 until I thought it was "good enough". Then I went over it with 320 until it was better. It felt smooth and looked smooth even after being wiped with a microfiber cloth. I went to put on my first coat of silver, and the rough spots and bubbles that I didn't see came out like stars in the sky...

I'll wet sand it and see what happens, but I doubt I'll get them out unless I sand the whole thing down to paper. What can I say? I'm a mechanical guy not a body man. :confused2:

 

[DAllen]

Dave, do you really think an Aura is lighter than this rocket?! I had one that was given to me by a friend, and the thing is a BRICK. By the looks of this one, it's made out of standard Estes/BMS tubing and therefore may actually weigh LESS than - or at the very least be comparable in weight to - the Aura.

Thus sayeth LOC:

https://www.rocketsbymelissa.com/uploads/RocketsCat2009-72.pdf

The Aura is 8 ounces built stock. Not only that but this rocket is longer and has 3 more fins thus more drag. So rockets2000 you got a postal scale handy? Any idea how much this bad boy weighs?

Also, rockets2000 what kind of paint for the silver were you using? I've never had good luck getting those allegedly "metallic" paints to look anything remotely metallic.

-Dave

 

[rockets2000]

Thus sayeth LOC:

https://www.rocketsbymelissa.com/uploads/RocketsCat2009-72.pdf

The Aura is 8 ounces built stock. Not only that but this rocket is longer and has 3 more fins thus more drag. So rockets2000 you got a postal scale handy? Any idea how much this bad boy weighs?

Also, rockets2000 what kind of paint for the silver were you using? I've never had good luck getting those allegedly "metallic" paints to look anything remotely metallic.

-Dave

RS9 tells me she weighs in at just under 7oz w/o motor, but I'm sure I'll put at least 2oz of paint on it before it looks right. The rocket is 38.25 tall. The six fins are pretty small, and I've blended the leading and trailing edges to reduce drag. So yes, this rocket is definitely longer and lighter than the Aura. I'll drag race an Aura any day! :dark:

I'm using Testors One Coat Lacquer in Diamond Dust, which is metal flake silver. It looks pretty good on the places where I sanded properly, and I'm going to apply a gloss clear coat once all the base coats are done. I've had good luck with this type of paint on the "Lil Dreamer" you see in the pics, however, that has a plastic BT. That one is blue metal flake.

 

[TheAviator]

I'm using Testors One Coat Lacquer in Diamond Dust, which is metal flake silver. It looks pretty good on the places where I sanded properly, and I'm going to apply a gloss clear coat once all the base coats are done. I've had good luck with this type of paint on the "Lil Dreamer" you see in the pics, however, that has a plastic BT. That one is blue metal flake.

Did you apply a clear coat over the "Lil Dreamer?" Clear coats tend to do dull metallic paints. If it worked on the other, it should work on this, but I would make a paint chip out of a scrap of something and test it first.

 

[rockets2000]

Yes, Lil Dreamer got clear coat too. Same brand (Testors), so maybe it works better than other brands over Testors paints. Dunno, but it looks good. I see a lot of people use Future floor polish. How much buffing is necessary to get depth to the paint?

 

[DAllen]

RS9 tells me she weighs in at just under 7oz w/o motor, but I'm sure I'll put at least 2oz of paint on it before it looks right. The rocket is 38.25 tall. The six fins are pretty small, and I've blended the leading and trailing edges to reduce drag. So yes, this rocket is definitely longer and lighter than the Aura. I'll drag race an Aura any day! :dark:

Don't forget that RS weights (along with altitude predictions) do not necessarily match reality. The weight you have is likely very close but not right on because RS has no way to determine the weight of the glue, paint, etc. If you are going to scratch build on a regular basis (and everyone should) a postage scale is an excellent investment. I predict you will be closer to 10 oz. if RS is saying 7.

-Dave

 

[rockets2000]

I can see where one would come in handy. I have a diet scale, but it has a spring, so I'm not getting 3-decimal accuracy. I weighed the parts that I have (still no motor or recovery system), and came up with just a little over 7oz. I'm guessing with the extra paint and kevlar cord/streamer I still have to put on, I'll be around 10-11oz minus the motor.

 

[rockets2000]

I sanded the rocket down properly this time and put 2 coats of primer on it. So far, it is free of defects and ready for paint. The nose cone is painted with 2 coats of silver and looks great. I should get it finished this weekend, but not in time to launch on Saturday.

 

[rockets2000]

Time for another update. I finished the rocket yesterday, and it looks AWESOME! I decided for the first few flights on Estes D/E motors to go with a 24" chute. Plus it's orange, so it goes with the theme.... The recovery anchor (leader + 8' of Kevlar) has swivel hooks on both ends, so it is easily reconfigurable for when I go to altitude and need a streamer.

I didn't take pics yet because I still had a couple of things to do like sand the fin fillets and clear coat the thing. I taped the BT and fins to just leave the fillet area I wanted to smooth out. Then I wrapped a strip of 600 W/D paper around a 1/8" dowel and knocked down the paint ridges left over from painting. Then it was time to clear coat. I didn't have much left in the can, so I decided to do the NC first. I chose wisely, because I did a really crappy job. YUCK! The clear coat ran and splotched, even after a rub down with some IPA. I didn't wet sand because I didn't know what it would do to the metallic paint. Anyway....I decided that I like the silver metallic without clear coat better - it gives the rocket an "aluminum" finish. The NC will be sanded again to get rid of the clear coat, and silver re-applied. Then she's ready to fly! I'll get some pics posted later.

 

[rockets2000]

Finally, the S2000 is painted! I still have to finish hooking up the recovery system, so it's not quite ready to fly yet. I've been working on my launch controller and pad, since I can't fly without them anyway. I'll post a controller build thread shortly. Anyway, here are the pics:

Finished with paint and decals

This shows the paint scheme with orange accent on the launch lugs and NC shoulder

Fin and lug alignment with red motor mount

Another look for scale

Skyward we go!

Glamour shot