Centuri's Early Concept Rocket

Originally posted by rosko_racer

Went to Wal-Mart and bought the Krylon's Red and Burgundy (kind of deep red). They did not have anything close to a charcoal gray so I will be visiting Hobby Works in Laurel after work and see what they have.

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HA! Then I will get to meet you at Hobby Works!

Rosko, that is an outstanding scratch build!!!

In fact, I'm so impressed that - if you can create your decals in an 8.5x11" page size, in a format I can print on my Alps or Epson printers, I'd be glad to print and clear the decals for you at no charge. I make my own decals for all of my projects (look at my V2 build or the attached photo for an example).

PM or Email me if you'd like.

Here is a fuzzy preview of the burgundy paint on the Phoenix. Sanded the entire rocket body with 220 then 320 sandpaper. A humid microfiber cloth took the sanded paint dust off. Two light coats of red paint with about 2 hours of drying time after each coat, then a heavy one keeping the rocket flat.... The red looks awesome.

Question: is there a way to polish the paint before applying decals? I would like to polish the paint then apply decals then seal everything with Krylon Crystal Klear

Here is the a look at the decal sheet. I think I am done with this part. I printed some of these on photo paper and they turned out very nice... of course, this pic does not give justice to the real one... ask rokitflite who saw the Phoenix with primer and the photo of the decals...

ABSOLUTELY GORGEOUS!!!

I was lucky enough to see this model in person yesterday and the pictures (even with their large size ) do not do this model justice! It is incredibly light for being carved out of solid balsa and should fly fine on as little as a B6-2. There is no way I could have done such an excellent job getting the smooth taper and clean even lines on the body! The decals are very sharp and well thought out and will look great on the model. Thanks for bringing it by Rosko!!!

Also you can use 3M finess-it (?) or Novus 2 plastic polish on the painted body before applying the decals, I have the latter if you need some

Got up this morning and followed someone's advice into making the nose cone with two transitions to simulate the flat tip. Then erased all the launch simulations to start fresh. I am using the sim with an 18mm MM.

FIRST - during one of the simulations the program gave me an error and shutdown the program.

Ran the program again. Loaded up all the basic loads and tried them... no problem then until I noticed that

SECOND - I could not select a D13 engine. I even selected to show ALL ENGINES was not on the database.

I kept going doing my simulations when I reran one and it said that the rocket crashed... even with an ejection charge. I decided to reran all simulations and

THIRD - all simulations resulted in a crashed rocket.

I turned off the software and brought it up again, selected the same file, then reran all sims with the same results - crashed.

Can anyone explain what happened here? Has this happened to anyone with RockSim V8?

Thanks.

I reran all the other .rkt files and did not have the above metioned crashes... I think that there is something with my rkt file. I did notices that the rocket was behaving different when I changed the NC but did not expect it to crash. The sims I ran immediately after the NC change were fine and I was refining the results to make a selection but the D13 was not around (?) and the crashes are a mystery... Where is Scooby Doo and the gang when you need them?

Originally posted by rokitflite

Also you can use 3M finess-it (?) or Novus 2 plastic polish on the painted body before applying the decals, I have the latter if you need some
[/B]

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rokitflite: where do I get that stuff to polish?

There are tons of places on the internet... Here is one of them:


https://www.tapplastics.com/shop/product.php?pid=113

Well, I rebooted the PC and ran the Sim... deleted all the previous engine load sims and started fresh. Ran what I think are the most common engines and this time it worked... check the attached chart... By the results I say that the C6-3 and Quests B6-4 are a good choice since the deployment veloc is not high. I prefer less that 50fps to be on the safe side. The C10-4 looks good to but it opens right before apogee as well as the C5-3. Analysis....

One thing: I am new to rocksim so here is a question - what does the "margin" mean?

Originally posted by rosko_racer
Well, I rebooted the PC and ran the Sim... deleted all the previous engine load sims and started fresh. Ran what I think are the most common engines and this time it worked... check the attached chart... By the results I say that the C6-3 and Quests B6-4 are a good choice since the deployment veloc is not high. I prefer less that 50fps to be on the safe side. The C10-4 looks good to but it opens right before apogee as well as the C5-3. Analysis....

One thing: I am new to rocksim so here is a question - what does the "margin" mean?

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Oh just fly it!

LOL.... OK rokitflite.... I will...

margin of stability

when the rocket kept crashing ,did you have a chute installed or a motor with ejection charge or too long delay? I'm curious about that

If you polish up the rocket mabey just wax it, krylon clear is about the worst spraycan clear as far as shine goes so that would be alot of work for the so-so results it gives.

looking great so far!

Originally posted by stymye
margin of stability

when the rocket kept crashing ,did you have a chute installed or a motor with ejection charge or too long delay? I'm curious about that

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The file had everything in place. The sims were run a couple of days ago and they were fine... I do not know what happened but all of a sudden it just did that... crashed... some kind of fluke or something... but it seems to be working now. What I am curious about is that on the engine database there was a D13 and now it is not on the database... puff, gone... Who makes those anyway? I checked around (apogee, sirius, estes...) and could not find the D13... Who actually makes it? Is it an 18MM engine? Sorry if I sound dumb but I looked around and did not find any info...

I have been slightly side tracked by my latest RockSim project, Yukikaze... Anyway I'm back with the Phoenix. I have painted it burgundy red and started polishing the paint with what I have at home: a superfine nail sanding block and Mother's Deep Crystal Polisyh system 1 and 2... it works fine for me.

I stopped polishing it and today I am covering the parts I want to keep red with painter's tape and tonigh it should get the first two coats of Gun Metal color from Tamiya.

I plan to attend this weekend's NARHAMs meeting after my NatGuard Drill. I plan to take this baby with me and maybe some of my other "in progress builds" and finished rockets, not many, about 6 total.

The circled part on the pic is the part I started sanding and it looks bumpy, but the polished parts look like it is made of plastic... it looks cool...

Ready for Gun Metal...

part two...

I posted a RockSim file for this design at:

https://www.rocketryforum.com/showthread.php?s=&threadid=26951

You might need to add some additional nose weight depending on where the CG lies in the finished product.

Attached is another version of the simulation where I tried to take into account the effect the oval shaped body will have on the rockets center of pressure. Note that this is not much different than the first file I posted where I ignored the effects of the oval body tube shape on the center of pressure.

Bruce S. Levison, NAR #69055

Originally posted by teflonrocketry1
I posted a RockSim file for this design at:

https://www.rocketryforum.com/showthread.php?s=&threadid=26951

You might need to add some additional nose weight depending on where the CG lies in the finished product.

Attached is another version of the simulation where I tried to take into account the effect the oval shaped body will have on the rockets center of pressure. Note that this is not much different than the first file I posted where I ignored the effects of the oval body tube shape on the center of pressure.

Quote from "Support and Recovery":
Here is my best attempt at the simulation of this design with an oval cross section. The nose cone was simulated as a cone giving the truncated part and a transition set with the same frontal area as your design. The main fins were appended to a set of body tubes placed at the appropriate distance on either side of the main body tube. The out board fins were assigned to fin mounts within the main fins (but RockSim won't draw them there). The aft transition also has the same frontal area as the nose cone. What is the real CG of your design? Is the balance point 10.5 inches from the tip of the nose cone on the empty rocket (no motor installed)? If not I would add nose weight to bring the CG to this point. I added 12 grams of nose weight to the design to get a stability margin of 1.05 with a C6-3 motor installed.

Bruce S. Levison, NAR #69055

Bruce S. Levison, NAR #69055

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Bruce: I looked at both mods, I like what you did with the files. I would like to know how you did the side tubes like you did because I could not find how to do it myself in the simulation. Also how you did the "fin mounts" on the main fins. This definetly looks like it is closer to the real thing. As for the model I am at the painting stage: tonight the main body gets the last coat of Gun Metal, the NC is not painted yet because I am working on it (the perfectionist in me...).

An since we are on this subject: Is it possible to put fins on a tube fin set?

As soon as I am done painting I will check the CG without the EM and the parachute/screw eye combo and post were it is.

Bruce, thanks for your help on this issue. You are really showing your knowledge of RockSim.

Here are several pics of the main body. I bought another can of Tamiya gun metal and spray painted the last wet coat (4th). Waited for about 1.5 hours and then removed the painters tape. Lines are sharp. I am going to wait until Tuesday to sand the paint with superfine sandpaper and then polish the paint to a nice shine. Will deal with the decals after I am done with the NC...

... and talking about the NC, it is still with the Kilz primer coat. I had to do some minor repairs and some sanding before painting. This should be done next week. Will post more pics later.

I am going to work on the decals at the end of the month. Once painted, decaled, and clear coated I will weight the rocket and check the CG with and without a C6-5 and look for a parachute... Oh,,, engine mount too...

rosko_racer

Awesome paint job, did you deliberately park the minivan with the similar paint scheme in the background? I see that the launch lugs are mounted on stand-offs. What size are these since they could add a lot of drag to your design?

To make side tubes and fin mounts I used the trick I invented for my Fins on Fins article at: https://www.apogeerockets.com/education/downloads/Newsletter113.pdf

In short all these tubes were first created as inside tubes with the correct location and orientation from the main body tube. Then I used a word processor (Wordpad) to change the appropriate lines in the RockSim file from <IsInsideTube>1</IsInsideTube> to <IsInsideTube>0</IsInsideTube> . This converts the inside tubes to outside tubes and allows you to assign fins and other parts to them as you would any other body tube when you reopen the file in RockSim.

It is possible to put fins on a tube fin set. There are several ways you can do this. The problem is that RockSim will not draw the fins at their proper locations due to the limitations of the programs graphical user interface. Give me an idea of how you want the fins located on the tube fins and I will post an example.

Bruce S. Levison, NAR #69055

Teflonrocketry1: Thanks for working on these files. That is the same newsletter I refered to earlien in the thread that I used to do the wing tips at the beggining. That was a cool tip.

The LL are standard 1/8 and they are mounted on flat 1/16 strips of balsa. I did not wanted to risk having the finish scratched upon launch. Both strips are 7/16" wide. One is 7/8" long and the other is 1 5/8" long.

Using your tip, on my Yukikaze project (see scratch built section) I converted two inside tubes into two regular tubes. I have not been able so far to add fins to them. I will work on that this evening once I am done with all the NatGuard stuff (we NCOs have to take care of our soldiers..) Any more trick under your sleave?

Quote: rosko_racer
Awesome paint job, did you deliberately park the minivan with the similar paint scheme in the background?

____________________________________________

teflonrocketry1: No, those red vehicles are my neighbors. I did not noticed them until I opened the pics in my computer. It was funny...

I am working on a Yukikaze scratchbuilt (file attached) and have been playing with editing the file with notepad. the Main fins are rooted to the main body and go through the tube fins. I changed the side tube fins into regular tubes (using your trick) and named them intake tubes. I tried to put the rear fins on them... like you said, no luck there. So I left them on the main tube.

I also placed an external tank tube with NCs but I am still plaing with that.... you can see it on the file...

Hack at it and let me know what you come up with.

I had a chance to spent some time on my Phoenix project on the last couple of nights: sanded and polished the paint on the booster section... it is looking good and smooth. All that is left is the NC... then the decals...

I polished the paint job on the main body and it is ready for decals... I have been toying this weekend and today with the idea of an 18mm adapter for the Phoenix so that I can use it with 18 and 24 mm as well... more later.

As for anchoring the shock cord, I plan to glue an engine block (inside the BT50) with a kevlar string attached and glued to it. If I go with the 18mm EM then I will attach it to the MM.

I gave the NC a gray primer coat and when I painted it burgundy, it looked darker than the rest of the body... so I sanded it and gave it a white primer color... left it there because I have to sand on the NC where it meets the body so it matches.

After following Sandman's earlier advice and waiting a month, the centering rings finally arrived yesterday. I dry fitted them on a BT50. There are two sizes: one for the main body which will take about 4-5 and the smaller for where the main body meets the NC.

I got to see this model up close and personal the other day. It's pretty. Really pretty. Cletus would say it's purdy.

And that's without the decals and stuff on it.

Nice work Rosko!

kj

It sure is! Great looking model Raul! Can't wait to see the Nosecone mated up with the body and finsihes. Very Sweet looking bird.

Thanks John.

I am finishing the NC for this project. At this point I have given it several coats of grey primer, a coat of flat white then a few coats of the burgundy red. I sanded lightly betweeen the primer and white coat. here is my problem...

This is the same can I used to paint the main body. As I gave a coat of the burgundy red (BR) two small bubbles developed. I later sanded the nc and gave it a third coat. Left it outside for about 30 minutes. When I picked it up it was flat red!!! this is a can of gloss paint and the NC ended up flat. I painted the last coat this morning. It was dry enought to give it a 600 grit sanding then a last coat. I gave it another coat and it turned something like semi-flat. Any thoughts on this? What may have caused the bubbles? What happened to the finish?

Primer left in direct sunlight,and humid weather might cause these bubbles more in a minute, but the flat red is a sure sign of high Humidity which has been creaping up in our area the last few days.

Back to the bubbles, over the weekend i've seen similar tiny bubbles in the Fresh and Easy primer i've been using. They haven't been bad enough worry about but I've stopped leaving the model outside to dry, even in the shade of my new mobile folding booth, instead spraying outside then bringing the model in to get them out out the humidity. I haven't seen any more of the nasty little things druing yesterday or last nights spraying If you look closely at the nosecone on my micro Taurus I think you can see a couple in this pic from friday afternoon.

Preparing the Phoenix for this weekend's launch, I painted the NC and added a long kevlar string to the motor mount. The motor mount was kindly donated by rokitflite: it can be preassure mounted and it has a bt-50 section at the end of it so that it does not go all the way into the rocket (Thanks Scott!!!). I'll secure it with some tape before flying it. I added a string of kevlar and tied fisher's interlock snap at the end and locked it to the NC. Still have not decided what parachute to put in it put it looks like a 12 or 18 inch one. I have several with interlock snaps on them... will choose when I get to the field.

Motor of choice: C6-5 for it's first flight...