No worries..
Multi Stage Saturn V
- Thread starter lakeroadster
- Start date
So, er uh, I've been lurking this one for a while but I noticed a drip in altitude prediction on the previousl page due to a base drag hack problem. Whihc is more and aerodynamic issue (i.e. when you're at speed). How're you doing with speed off the rail? I think it's really cool to have lots of fire and a dramitic, slower than usual ascent and not get lost in the stratosphere, but are you needing a longer, sturdier rod/rail? My brother-in-law's V2 appears to suufer from that problem.
Building Apogee 1/70 scale Saturn V. I would like to display it. I have looked at many towers...non I like. Is there a proper scale one out there?
Speed off the rail is still fine, see simulation below. Even if one of the C11 motors doesn't fire, it's still above 30 mph. I use a clip whip that has a leads for each e-match in each motor and have yet to have a misfire on a 24mm BP motor when launching clusters.
As to the previous "dip in altitude"... I fat fingered the drag override and applied it to the 4th stage, and not the 1st stage. Once I fixed that, the drag of the 1st stage drops off quickly at staging and the apogee is about 980 feet, that's optimistic IMO.
Dealing with base drag on this multi stage rocket is messy and appears to be beyond the capability of Open Rocket. Think about it. Each stage of this rocket design experiences base drag. But that base drag for each of those upper stages doesn't occur until each staging event happens. So to be accurate, the base drag cone needs to be added at staging, but not before staging occurs.
If I add base drag cones to all the stages of the simulation, and leave them in place. The apogee is 958 feet, that's conservative.
What's all that mean? I expect the apogee to be somewhere between those two numbers... ( 980 + 958 ) / 2 = 969 feet.
I'm hoping to lay down some tape lines to create the mask, and then paint the flat black roll pattern today or tomorrow.
With any luck we can light the fires on this bird in April.
I should have named this "Kronos" instead of Saturn V....
The Saturn Family
- Saturn I – Ten rockets flew. It was five development flights and five launches of boilerplate Apollo spacecraft and Pegasus micrometeoroid satellites.
- Saturn IB – nine launches. It was a refined version of the Saturn I with a more powerful first stage (designated the S-IB) and using the Saturn V’s S-IVB as a second stage. These carried the first Apollo flight crew, plus three Skylab and one Apollo-Soyuz crew, into Earth orbit.
- Saturn V – Thirteen launches. The Moon rocket took the Apollo astronauts to the Moon and carried the Skylab space station into orbit.
Laying Out The Roll Pattern
Using the Saturn V scaled data that @Ez2cDave posted previously, and the data that Apogee Components supplied on their website for their 1/70 scale version I laid out the roll pattern.
Somehow when modeling and drawing this rocket I left out the S-IC/S-II Interstage... basically a spool section that fits between the 1st and 2nd stage, which means my rocket is 1.48" to short in the main 3" dia. section. That's the piece you see at about the 2:25 mark in the video below.
So if your judging scale points on this rocket... please deduct that oversight accordingly.
Using the Saturn V scaled data that @Ez2cDave posted previously, and the data that Apogee Components supplied on their website for their 1/70 scale version I laid out the roll pattern.
Somehow when modeling and drawing this rocket I left out the S-IC/S-II Interstage... basically a spool section that fits between the 1st and 2nd stage, which means my rocket is 1.48" to short in the main 3" dia. section. That's the piece you see at about the 2:25 mark in the video below.
So if your judging scale points on this rocket... please deduct that oversight accordingly.
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Bag is empty....................................Continues to watch (thinking of my recent Mini Alpha eff up)......
Well, I'm glad to hear that your speed is ok off the rail... and I understand the base drag thing, and why it might be past the capabilities of Open Rocket (though TBH, I haven't gotten into any of the simulators yet). I like the analytical/engineering effort you've put into this, combined with some intersting innovations - makes me a bit jealous! I simply have to find more time for this... But yeah, figure at staging each remaining part of the rocket has both an initial velocity and instantaneous base drag - but does OR differentiate between engine firing vs. coast? It's stuff like this that I really want to sink my teeth into.
Best to you, hope the painting goes well, and hey - who needs a stinking interestage when you have 4 stages... unless... unless... you simply can't unsee it!
Masking For Roll Pattern
I'm using some "3M Automotive Performance Masking Tape" this time around. In the past I've been using "Blue Painters Tape" and have had some edge bleed issues. This tape seems to stick better, yet not be too sticky. We'll see how it goes.
I'm using some "3M Automotive Performance Masking Tape" this time around. In the past I've been using "Blue Painters Tape" and have had some edge bleed issues. This tape seems to stick better, yet not be too sticky. We'll see how it goes.
Well, I'm glad to hear that your speed is ok off the rail... and I understand the base drag thing, and why it might be past the capabilities of Open Rocket (though TBH, I haven't gotten into any of the simulators yet). I like the analytical/engineering effort you've put into this, combined with some intersting innovations - makes me a bit jealous! I simply have to find more time for this... But yeah, figure at staging each remaining part of the rocket has both an initial velocity and instantaneous base drag - but does OR differentiate between engine firing vs. coast? It's stuff like this that I really want to sink my teeth into.
Best to you, hope the painting goes well, and hey - who needs a stinking interestage when you have 4 stages... unless... unless... you simply can't unsee it!
Thanks for the comments.
Yes Open Rocket does differentiate between the thrust and coast phases.
- For a visual, the plot function shows various "Events" such as Motor Ignition", "motor burnout", "Ejection Charge" etc.
- You can also do an "Export" of the simulation and the program creates an Excel spreadsheet that shows a plethora of data, including all those "Events".
I like the export function. It allows me to go in and clean up the worksheet so it's more of the style I'm familiar with.
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Some observations: You were considering having the tower pop off at landing; Why not fly it off the top of the stack like the original, after it clears the Launch rod (tower)?
If you need to feed a fuse thru something flammable, you can run it thru a piece of brass tube from HL.
If you need to feed a fuse thru something flammable, you can run it thru a piece of brass tube from HL.
Painting The Roll Pattern
A bit chilly here today... kind of pushing the paint temperature envelope. Since I use flat paint I seem to have success with painting as long as the temp. is above 40 F. It was also windy today... so I spray painted beside our wood shed, using it as a wind break.
I started with a light coat of flat white since the base coat is flat white. I focus on painting the edges of the masking tape. This typically helps seal the edges of the tape and if there is any seepage under the tape, it's the same color as the base coat.
After the white has about 10 minutes of drying time I spray the flat black. I did 2 coats, waiting about 10 minutes between coats.
I then moved the rocket over next to our barn. The sun is pretty intense this year and the barn siding gets warm to the touch from the sun. This works pretty well to keep the paint warm while it's curing.
I'll wait a couple hours, then move the rocket into our garage and remove the masking tape. I always like to do that the same day as I paint.
The rocket looks really awesome in black.... kind of stealthy. Just what you don't want for a 4 stage rocket.
A bit chilly here today... kind of pushing the paint temperature envelope. Since I use flat paint I seem to have success with painting as long as the temp. is above 40 F. It was also windy today... so I spray painted beside our wood shed, using it as a wind break.
I started with a light coat of flat white since the base coat is flat white. I focus on painting the edges of the masking tape. This typically helps seal the edges of the tape and if there is any seepage under the tape, it's the same color as the base coat.
After the white has about 10 minutes of drying time I spray the flat black. I did 2 coats, waiting about 10 minutes between coats.
I then moved the rocket over next to our barn. The sun is pretty intense this year and the barn siding gets warm to the touch from the sun. This works pretty well to keep the paint warm while it's curing.
I'll wait a couple hours, then move the rocket into our garage and remove the masking tape. I always like to do that the same day as I paint.
The rocket looks really awesome in black.... kind of stealthy. Just what you don't want for a 4 stage rocket.
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That's about a 2.3% difference. With the variation one sees in engine performance, and the other miscellaneous limitations simulation accuracy, that's way down in the noise.
The QA department was inspecting the roll pattern paint job...
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Certainly.. I'm merely sharing data.
Messing with the coefficient of drag for the entire rocket.... on a 4 stage rocket, is.. well... messy.
Oh, deer...
Roll Pattern... Engage!
Removed the "3M Automotive Performance Masking Tape" and the roll pattern turned out pretty nice. I'll have to do some touch up work... but not much.
The only places the tape removed any of the flat white base coat was adjacent to one of the vent holes, and on the papered fins in a few spots. Very minimal, no worries.
And there was some bleed through, mostly at the tip of the engine fairings. I expected that, it's tough to get the tape into that joint. There's also some bleeding where the canted fins meet the engine fairings. I didn't worry about that area much when masking, I'll be hand painting the fins silver.
I took a lot of photo's to show how the paint lines looked in the raw. Keep in mind the paint is not fully cured by any means. I pulled the mask about 2 hours after I painted the flat black.
Removed the "3M Automotive Performance Masking Tape" and the roll pattern turned out pretty nice. I'll have to do some touch up work... but not much.
The only places the tape removed any of the flat white base coat was adjacent to one of the vent holes, and on the papered fins in a few spots. Very minimal, no worries.
And there was some bleed through, mostly at the tip of the engine fairings. I expected that, it's tough to get the tape into that joint. There's also some bleeding where the canted fins meet the engine fairings. I didn't worry about that area much when masking, I'll be hand painting the fins silver.
I took a lot of photo's to show how the paint lines looked in the raw. Keep in mind the paint is not fully cured by any means. I pulled the mask about 2 hours after I painted the flat black.
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That must be Clarice looking for Rudolph at Santa's workshop. Springtime at the North Pole. The paint smells so sweet.
Overall, how does the green tape compare to the blue?
The "3M Automotive Performance Masking Tape" is much better than 3M Blue Painters Tape.
But... you best be sure that the base coat is adhered well. I used it on flat white and I think it would work even better over semi-gloss or gloss base paints.
Honestly I kept waiting for it to yank the white paint off, but it didn't, well except for some very small pin-head sized spots on the papered basswood fins.
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Service Module Wrap
I searched here on TRF and found a nice Saturn 1B Service Module wrap, thanks to member @Saluki. I massaged the proportions to fit my quazi 1/132 scale Saturn V.
Using watered down Gorilla Wood Glue: 2 parts glue - 1 part water, I used a small brush to coat the back of the wrap and then placed it on the Service Module. Once the rocket is clear coated it should be go for throttle up.
I searched here on TRF and found a nice Saturn 1B Service Module wrap, thanks to member @Saluki. I massaged the proportions to fit my quazi 1/132 scale Saturn V.
Using watered down Gorilla Wood Glue: 2 parts glue - 1 part water, I used a small brush to coat the back of the wrap and then placed it on the Service Module. Once the rocket is clear coated it should be go for throttle up.
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Hand Painting Day 01: Flat White & Flat Olive Drab
I sprayed some of the flat Rusto white into a cup and used that and a small detail paint brush to touch up all the flat black that had bled under the masking tape. You can see the "before photo's above, see post #530".
Next I used some flat Split Pea (olive drab) Testor's to paint the bottom of the 1st stage.
So far so good. I need to pick up some silver Testor's @ the local hobby shop to hand paint the fins with... and then spray some clear in preparation for decals.
I sprayed some of the flat Rusto white into a cup and used that and a small detail paint brush to touch up all the flat black that had bled under the masking tape. You can see the "before photo's above, see post #530".
Next I used some flat Split Pea (olive drab) Testor's to paint the bottom of the 1st stage.
So far so good. I need to pick up some silver Testor's @ the local hobby shop to hand paint the fins with... and then spray some clear in preparation for decals.
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Try this after you apply blue tape run a small amount of caulk along the tape edge let dry amazing results clear line when removed
That's a new one on me. I've seen Tim Van Milligan use some sort of clear sealer.
What kind of caulk are you suggesting?
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Hand Painting Day 02: Flat Silver Metallic
Painted the fins.
Painted the fins.
Any paintable type from Dap.
