What did you do rocket wise today?

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I managed to hold off buying a bunch of stuff on sale for another day. My strength is weakening though...
 
Used up the last of the aluminum foil and found an airframe in the box, lol. Then I looked for the other half of it in the parchment paper box, haha!
 
Ripped off a wrong-sized launch lug from a minimum-diameter rocket, and some of the body tube in the process.
 
Ripped off a wrong-sized launch lug from a minimum-diameter rocket, and some of the body tube in the process.
That’ll teach ya to put launch lugs on a min-diameter rocket! ;)

(Ouch! Sorry to hear that!)

Me: designed a modified Go Devil 38 maybe for my next build.
 
Very very nice designs! I might try entering them into OR and playing. Would love to see your pictures of the actual printed models.

Thanks, will have some pictures and video to follow soon, first test flight on a D motor went great.
Very nice. Do you plan to get those polished metallic finishes?

At the moment I am just leaving them unfinished in the colours they were printed in, however I might use aluminium foil tape for a metallic finish, metallic silver painting 3d printed parts requires a lot of effort sanding to get a nice finish.
 
In the absence of West System 406 filler here in Australia, and given my dislike for the 413 microfibre for sanding smoothness, tonight I started experimenting with SIG microbaloons...

IMG_0574.jpg

105/206/SIG Microbaloons mixed to a stiff cake icing (frosting) consistency then laid in a test butt joint.

No fillet pulling here, as the main goal is to test both strength and sand-ability.

IMG_0577.jpg
 
View attachment 366932 Trying to figure out how to do this

Have Sandman custom turn the upper section into a balsa nose cone.
Cut grooves and add balsa fins.
3D print the 4 into 1 tube coupler (separation point) and base unit to adapt to 4 tubes and take 4 fins.
I take it the nossels will be engine retainers?
 
Have Sandman custom turn the upper section into a balsa nose cone.
Cut grooves and add balsa fins.
3D print the 4 into 1 tube coupler (separation point) and base unit to adapt to 4 tubes and take 4 fins.
I take it the nossels will be engine retainers?

Thx. Its just the RM10 sustainer that I am thinking about building -- although the twin Deacon booster in the Wallops Island picture look very cool. I have an idea for molding the airframe. Trying to decide if I want this to be my first fiberglass project, or my first polyurea project.
 
Preparing Mach1 BT55 Scat parts for assembly
 

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Last night I attached upper fins on my DarkStar Jr. with JB Weld. This morning I was hashing out plans for integrating EggFinder with the NC & payload section. The idea is to allow the whole thing to be reconfigurable in case I want to go DD in the future. I think I have it figured out.
 
Just got back from another excellent launch at TRA/PHX. Started cleaning up rockets and was having a hard time getting a CTI 54 6 grain out of my fireflyer. Ended up pushing it out forward through the fincan, only to find this:
DSCF0669.jpg

Oh well, at least it's one case I won't have to clean...

It was a great flight on a K750 Red Lightning, Mach 1.5 and 15,213 ft. Testing the latest version of the Featherweight GPS.
These new 2.6" kits with 54mm MMT's really perform well:

DSCF0666.jpg
 
Can those dimensions be correct? To my eye they don't agree with the pictured unit.

No. They weren't. I edited the post to correct the length. The dimensions still aren't right, but they are less wrong.

No need to guess about the dimensions of the RM-10. They are in Peter Alway's 2001 supplement to Rockets of the World. And came from a NACA report https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092188.pdf

The body reaches a maximum diameter of 12" (304.8mm) at STA 90" (2286mm).
The fin root starts at STA 129" (3276.6mm)
The body/fin root ends at STA 146.5" (3771.9mm)
Diameter of body at STA 146.5" is 7.272" (184.7088mm)
The fin leading edge ends at 151.632" (3851.4528mm)
The fin ends at STA169.772" (4312.2088mm)
Fin span is 35.88" (911.352mm)
Fin width, perpendicular to the leading edge is 9.07" (230.378mm)
Max Fin thickness is 0.907" (23.0378mm)
"The fins were swept back 60° and incorporated 10-percent-thick circular-arc airfoil sections normal to the lending edge."

The diameter of the body at any STA point, in inches, is given by:

dia = 12-((90-STA)^2/675)

Neither the NCAA report, nor Alway mention anything about the tips of the fins have a radius, so I don't know if the values you have are valid or not.

Several other sizes were made and tested in wind tunnels and flown. They were all sized relative to the full length of the parabolic arcs that define the shape (180" for this example). According to the report:
The radius at any STA = (STA/7.5)*(1-STA/L)
The fin span is 0.1994*L
The fin tip length is .0504*L
The body ends where the diameter = .0405*L or at 81.33% of L.

There do seem to be some inconsistencies in the report. The report gives the 146.5" length and base diameter as 7.272" but those do not quite match the equations. Using 180" for L, the body would be 146.394" and the base diameter would be 7.29". So either the model makers ended up making the model a little longer called for or 180" isn't the correct L.




Alway's supplement also has data on the RM-2 and E-17. No data on that booster though.
 
>snip< No data on that booster though.

Thanks. <smile>

I wasn't guessing as much as I was sketching. And original length on the drawing (now "corrected" to a different wrong number) was a typo.

I have the NACA reports with measured drawings of models at different scales. The drawing I posted was a free-hand copy (drawn with the bezier pen tool in Illustrator -- not a computed profile) of the 50% wind tunnel model.

RM10_revA_comp_todrwg1.png

I am not planning an entry for a scale competition. I am thinking about it as a problem in construction. I want to try mold making and laying up composites. The design -- in broad strokes -- recommend itself as a challenging shape. The dimensions I marked up on the sketch were mostly an attempt to work-out if I could mill the mold on my CNC. I made multiple arithmetic errors.

The booster in the Wallops Island image -- according to this site -- is a "double deacon booster".

https://launiusr.wordpress.com/2017/04/17/robert-gilruth-and-the-nacas-entry-into-space-technology/
 
Pulled the tape, applied a sharpie, and dry fit. Ready to glue together the ASM (Atmospheric Space Modulator!) and then do decals.

20181120_081504.jpg




I am not planning an entry for a scale competition. I am thinking about it as a problem in construction. I want to try mold making and laying up composites. The design -- in broad strokes -- recommend itself as a challenging shape. The dimensions I marked up on the sketch were mostly an attempt to work-out if I could mill the mold on my CNC. I made multiple arithmetic errors.

Whatever you do, now you owe us a build/technique thread.
 
After basecoating these the other day, need to give them several days to dry completely.
IMG_20181120_022832.jpg

So I got antsy, and pulled these last night for a quick build:
IMG_20181120_051241.jpg

Next, flat white primer, several light coats of fluorescent paint, decals with Microset, and clear coat.

Nytrunner, nice ASM. I like that you went with blue instead of red. The white decals should really pop on that one.
 
Nytrunner, nice ASM. I like that you went with blue instead of red. The white decals should really pop on that one

Thanks! For some reason I can't bring myself to paint what's on the facecard, and color inversion seemed interesting. Is it red? It always looked orange to me
 
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