Discussion in 'The Watering Hole' started by RocketEnthusiast101, Nov 22, 2019.
Hi. I see everyone painting their rockets. Is it part of NAR necessity or well why not.
Painting your rockets is not "part of NAR necessity". It is optional and a personal preference either way. I find that rockets painted in garish bright colors are easier to track in the sky and locate on the ground. That said I have never flown naked but I don't look down on those that do (too much, anyway) .
Not necessary, in spite of the Stickershock motto.
It depends on what your goals are.
If you're just having fun and you enjoy flying and not so much building, then painting is not necessary.
If you're trying to make a rocket that looks really good, or matches an actual rocket, then yet it's probably necessary.
If you're going for maximum altitude then it's absolutely necessary because a finished rocket will have less drag than an unfinished rocket and will fly higher.
There are other reasons to finish or to not finish, but ultimately it's up to you and what you want to achieve. It's not a requirement.
alirght lol. Thanks for the reply. Asked it cause i wanna save time.
so the paint reduces drag on the rocket? This is interesting. I thought that it would increase drag on the rocket.
Paint does offer a level of protection to paper and wood rockets, particularly from moisture.
Depends on how good of a finish you get.
Certainly, most paint surfaces would have less drag than most bare wood surfaces, but plastic and glassine body tubes probably won't benefit too much if at all.
alright. Thanks a lot for this interesting info. I will do more research into it.
That really depends on what materials your rocket is made of.
Cardboard tubes are sometimes rough, sometimes smooth, but all have a spiral groove running around them that will create some drag. A smooth finish of paint and cover of smooth clear coat will have MUCH less drag than rough cardboard.
Fins made of balsa, or any wood I suppose, can be rough if not finished.
Nosecones that are made of plastic typically have a seam that can cause a lot of turbulence and drag if not sanded off.
All these materials will arrive in kits in varying degrees of roughness. Usually sanding the wood smooth with high grit sandpaper, a couple of coats of primer with good sanding in between coats, a couple of good coats of paint (no drips), and a finish clear coat will leave your rocket super smooth and with much less drag than an unfinished rocket and fly much higher.
If you're building a rocket to fly above the Karman Line you'll be using completely different materials, but a super smooth finish will always help.
Mushtang wrote about as good an answer as you could ask for.
One small additional note I'll add is that paint reduces drag but also adds weight, so oftentimes paint will be minimized on items that really benefit from absolute minimum weight, such as gliders and helicopter recovery models.
Just for laughs I made a quick sim in OR for an 18mm minimum-diameter rocket flying on a C6-7 (in other words, fly and bye-bye).
With nose and BT set to "unfinished", and fins set to "rough", sim altitude is 1446'. With all components set to "regular paint", sim altitude is 1607'. With "polished paint", 1897'. So you can see that surface drag can have quite a bit of effect on achieved altitude.
Note this sim is very incomplete, and doesn't account for the weight of the paint, but it should give an idea about the effects of surface drag.
Not needed but nice. I usually let my rocket earn their paint.
When you fly out in the desert any paint you have is going to get trashed when the winds drag it along the ground by the parachute. I build a lot of rockets with colored fiberglass... no paint necessary, and you just wipe off the dirt.
I did a test with my mpr Gallo 24, a bt60 tube with a 24mm mmt. I glued the fins in completely rough cut on the edges no rounding or sanding, in finished up painted went up on a Estes E12-8 and hit 875' apogee. Then beveled the fin edges sanded and painted the rocket, flew again on a E12-8 to 1182'.
My L2 Lead Sled is all filled spirals, sanded transitions, polished paint and it does really well for the weight. My ARTS 2 reported the flight on a CTI J530 IMAX has having a drag coefficient of .3 something.
Painting is critical in real aeronautics. Especially with regards to corrosion and drag. For models, it will also protect the underlying surface.
The weight of paint is a significant factor that probably offsets any performance gain you get from a polished paint job. The reason they stopped painting the space shuttle external tank was to save weight.
There is a 4-part blog posting about this issue, good reading.
Thankfully we aren't NASA, so I will continue to build in a way that makes me happy.
Glossy paint is generally smoother than naked paper and wood, and smooth has less air resistance.
I use to do Automotive Custom Painting.
Everything in the build for me comes to putting a first class paint job on it.
Even though all those hours of work may be lost on it's first flight by updrafts, failed chute or CATO.
It's just the FUN and PRIDE for me.
And I HATE self adhesive decals for rockets with a passion. (Except Stickershock Vinyl that is)
@Woody's Workshop how much would you expect an auto shop to charge if I asked them to paint a 4"/10' fiberglass rocket with whatever leftover paint they have (it hasn't been primered yet)?
It's been over 20 years since I dealt with estimating, so I'm sure I am not going to be accurate.
But I'm pretty sure it will be in the hundreds. Rockets ain't the easiest things to paint.
BC/CC systems are not cheap, and water born paints require expensive guns.
Best advice I can give is buddy up to someone who owns, or works in a body shop.
You might get it done on a weekend for some beer and you help.
And only after that did chunks of insulation start falling off of it during launches. If it had still been painted the Columbia would probably not have been damaged and destroyed.
If you decide not to paint especially card board and wood I would at least shoot a coat of primer to protect the card board.
Primer is porous, though... not the best protector.
You can protect it from moisture and still proudly not paint; just hit the naked rocket with clear coat.
And seven brave Astronauts might still be alive.
Current TARC rules apply a penalty if the rocket is unpainted at all.
"Push the envelope" and paint it clear . . . If they penalize you, file a formal protest, citing that the TARC rules do not state that the paint must be "pigmented" . . . Fight back against "the man" ! ! !
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