Dimpled nose cones

[Josh Kellogg]

I saw on a program recently that golf balls have dimpled surfaces because it makes them more aerodynamic. Is this, or could this also be done to rocket nose cones to help make them more aerodynamic and soar up faster, or is the cone shape aerodynamic enough? And also, since some of the fat man rockets don't have as pointed off a nose cone as taller and more slim rockets do, could dimpling the cone help them be aerodynamic enough to go higher?

 

[trialsguy]

A traveling nose cone with a rocket body behind it affects the air around it much differently than a traveling sphere with nothing behind it but air. The dimples on a golf ball reduce drag by assisting the air molecules to travel around the outside of the ball and then cause much of the air molecules to close behind it, thereby reducing the drags on the golf ball. With out the dimples, the ball would be pulling a greater vacuum behind it, thus slowing its forward progress to a greater degree.

 

[Josh Kellogg]

Ohhh OK. That makes a lot of sense! Thank you!

A traveling nose cone with a rocket body behind it affects the air around it much differently than a traveling sphere with nothing behind it but air. The dimples on a golf ball reduce drag by assisting the air molecules to travel around the outside of the ball and then cause much of the air molecules to close behind it, thereby reducing the drags on the golf ball. With out the dimples, the ball would be pulling a greater vacuum behind it, thus slowing its forward progress to a greater degree.

 

[TimothyG]

So would having a dimpled boat tail help decrease drag during coasting faze of the flight then? Would be fun to have a large draggy rocket and compare different boat tail designs on a set equal airframe.

 

[cbrarick]

sounds like a science fair project for one of our younger members...

 

[Nytrunner]

And also, since some of the fat man rockets don't have as pointed off a nose cone as taller and more slim rockets do, could dimpling the cone help them be aerodynamic enough to go higher?

Usually the point of such rocketes is not to go higher. Keeps the flame and noise experience closer to the ground

 

[gna]

So would having a dimpled boat tail help decrease drag during coasting faze of the flight then? Would be fun to have a large draggy rocket and compare different boat tail designs on a set equal airframe.

https://www.scientificamerican.com/article/how-do-dimples-in-golf-ba/
https://www.racecar-engineering.com...can-dimpled-aerodynamic-surfaces-reduce-drag/

Worth a try.
Making the dimples seems to be a problem...

 

[K'Tesh]

https://www.scientificamerican.com/article/how-do-dimples-in-golf-ba/

I'd vote for tests using the "Big Daddy"... Who knows, might stop them from drag separating.

 

[heada]

Back in the day, there was an Estes kit called the Rock-it. Nosecone had depressions in it and a stippled look made to resemble rock. It was based on the fat boy just with a modified nosecone. With 3d printing, it should be fairly simple to print a nosecone and tailcone with varying size and number of dimples. Use a smooth version as a control. See if the dimpled rocket flies higher/lower than the control and see if the number and size make a difference. 4 or 5 flights of each configuration and average your results. Science fair 101 stuff right there!

I wonder if Estes would sponsor the motors for something like that?

 

[Nytrunner]

@TurbulentSphere When you're bored with grid fins, you could start printing dimple rockets

 

[TurbulentSphere]

@TurbulentSphere When you're bored with grid fins, you could start printing dimple rockets

Tempting. I think I have a Big Daddy kit laying around somewhere....

 

[David Schwantz]

A traveling nose cone with a rocket body behind it affects the air around it much differently than a traveling sphere with nothing behind it but air. The dimples on a golf ball reduce drag by assisting the air molecules to travel around the outside of the ball and then cause much of the air molecules to close behind it, thereby reducing the drags on the golf ball. With out the dimples, the ball would be pulling a greater vacuum behind it, thus slowing its forward progress to a greater degree.

Nope, it is because it is round

 

[K'Tesh]

https://www.scientificamerican.com/article/how-do-dimples-in-golf-ba/

I'd vote for tests using the "Big Daddy"... Who knows, might stop them from drag separating.

 

[Josh Kellogg]

Usually the point of such rocketes is not to go higher. Keeps the flame and noise experience closer to the ground

That makes a lot of sense.

 

[Josh Kellogg]

Could we somehow approach them with the idea? I mean, they have a rocket for launching eggs, so I don't see why they wouldn't have a dimpled rocket.

Back in the day, there was an Estes kit called the Rock-it. Nosecone had depressions in it and a stippled look made to resemble rock. It was based on the fat boy just with a modified nosecone. With 3d printing, it should be fairly simple to print a nosecone and tailcone with varying size and number of dimples. Use a smooth version as a control. See if the dimpled rocket flies higher/lower than the control and see if the number and size make a difference. 4 or 5 flights of each configuration and average your results. Science fair 101 stuff right there!

I wonder if Estes would sponsor the motors for something like that?

 

[Josh Kellogg]

A traveling nose cone with a rocket body behind it affects the air around it much differently than a traveling sphere with nothing behind it but air. The dimples on a golf ball reduce drag by assisting the air molecules to travel around the outside of the ball and then cause much of the air molecules to close behind it, thereby reducing the drags on the golf ball. With out the dimples, the ball would be pulling a greater vacuum behind it, thus slowing its forward progress to a greater degree.

I have question in regards to that then, if the dimples help reduce drag from the vacuum in the back end of a golf ball, if we make the whole rocket dimpled, would that in theory cut down the drag on the back of non foiled fins, and cut down drag from the end of the body, especially during the coasting phase?

 

[gtg738w]

Dimples trip the boundary layer to become turbulent and turbulent flow stays attached to the aft face longer before it separates. If you had a rocket with a spherical or very steep boat tail it might help on the aft end. Most rockets are long enough and with other trip sources, the flow is probably already transitioned naturally.

 

[Tyler P]

Back in the day, there was an Estes kit called the Rock-it. Nosecone had depressions in it and a stippled look made to resemble rock. It was based on the fat boy just with a modified nosecone. With 3d printing, it should be fairly simple to print a nosecone and tailcone with varying size and number of dimples. Use a smooth version as a control. See if the dimpled rocket flies higher/lower than the control and see if the number and size make a difference. 4 or 5 flights of each configuration and average your results. Science fair 101 stuff right there!

I wonder if Estes would sponsor the motors for something like that?

I have one of those Rock-its in my build pile. Might get to it while I'm waiting for our store to re-open in a couple weeks.