What are some ways to increase drag on a High Powered Rocket?

Hi,

As the title states, I would like to know some ways to increase drag on a rocket. I am building a rocket that has a specific altitude goal (3000' AGL) and a weight limit. I am required to use the CTI I-540 motor and even at maximum weight limit, RockSim is giving me a projected altitude of ~3050'. In the past, all the sims that I have run have undershot the actual flight altitude. I was thinking something like gluing some strips of this to the leading edge of the fins to increase surface area:


What do you guys think? Thanks for the help!

Thickened fins, blunt fins or nosecone, streamers on the fin ends, projections from the tubes, uneven textures...

Yup, thick blunt fins and projections. A sawed off nose cone maybe?
Ken

Big Fins.

https://www.rocketryforum.com/showthread.php?37367-Upward-Propensity-My-Level-2-rocket

That is all.

Juggernaut what is your finnish on the components of your design. The default is polished, set it to matte and run the simulation. You should see a difference and reach your goal as designed thus far.

pods come to mind, especially with blunt nosecones (bulkplates?) I'm sure we can make this thing stay on the rod/rail if we try hard enough
On my L1 I had weight in the nose cone AND 8 oz of lead sheeting wrapped around the aeropack 38-29 adaptor.....mmmm heavy rocket, balanced with weight forward and aft so as to not upset the CG

An interesting challenge. What's the general configuration of the rocket? Is this predetermined? Do you get test firings before the contest shot?

In addition to suggestions made above (particularly the setting of components to "matte" in Rocksim), other things you may wish to consider: fin positioning. Tube fins. Planar fins that are curved or warped without rounded leading edges. Increasing airframe diameter...


Later!

--Coop

"What are some ways to increase drag on a High Powered Rocket?"

You could have me build it.

get some sticky backed sand paper. We use it for icing sims on aircraft. Drag goes up pretty quick

Shag carpet.

cvanc said:

Shag carpet.

Click to expand...

I would love to see a shag carpet rocket.

A dress, lipstick and high-heel shoes. Oh, and a wig!

More drag than Mardi Gras :rofl:

Krusty

What size rocket are we talking about. First thing that comes to mind is add fins.

If it's 3 add another to make 4 or even 5 fins. That's the easiest route.

You can increase body diameter.

Until I know what you are dealing with...it's hard to give accurate advice.

How about some specs?

krusty said:

A dress, lipstick and high-heel shoes. Oh, and a wig!

More drag than Mardi Gras :rofl:

Krusty

Click to expand...

Sure beats my ball and chain recovery system!

Add spin tabs - essentially add small wedges on the back ends of each fin - this increases rotational energy and stability at the expense of altitude.

Paint with Flecstone (spelling?) - textured paint.

Mount fins with a slight degree away from parallel to the long axis of the rocket - 1/2 degree maybe. This like the spin tabs increases spin. I like spin tabs better because they can be designed to be removable and only used when required.

Add tubes to the end of the fins.

Switch to tube fins.

etc.

Drag disk. A removable disk that slides over the airframe with slots that allow it to slide about half way over the fins.

Bob

Juggernaut said:

Hi,

As the title states, I would like to know some ways to increase drag on a rocket. I am building a rocket that has a specific altitude goal (3000' AGL) and a weight limit. I am required to use the CTI I-540 motor and even at maximum weight limit, RockSim is giving me a projected altitude of ~3050'. In the past, all the sims that I have run have undershot the actual flight altitude. I was thinking something like gluing some strips of this to the leading edge of the fins to increase surface area:
View attachment 116883

What do you guys think? Thanks for the help!

Click to expand...

Try some dingle balls.

Dork_Vader said:

I would love to see a shag carpet rocket.

Click to expand...

And, it's definitely draggy ... it reaches about 600' on a K motor.

-- Roger

Shape of the fin can help. The less swept back the leading edge is the greater the drag. In Roc-Sim, you can fine tune this pretty well, and it doesn't take that much from as close as where you are right now. Shaving altitude by approx. 50' doesn't require that much alteration. That also increases stability by moving the CP aft.

You could experiment by adding nose weight, but you might find that change might actually increase your altitude.

Spend a good hour or to in Roc sim making fine adjustments in these two areas and you should be able to shave 50' without doing anything drastic.

I'd suggest RasAero rather than Rocksim for that sort of adjustment.

Base diameter will have the biggest effect. Bigger tube, cone at the bottom, disk at the bottom. Or if you don't mind frying it, recess the motor up in a tube. Acts like an oversized nozzle and kills the motor's performance.

I think it is more in the transonic and supersonic range where blunt leading edges and nosecones pretty much keep it from going beyond transonic as the power requirement goes way up. Rounded or elliptical leading edge shapes and tapered trailing edge shapes are lower drag at lower speeds. Ditto fins that stick straighter from the tube. Vastly oversimplified, but that's part of why you don't see sharp leading edges and highly swept wings on slow airplanes (except for toys).

Gerald

Drag Doughnut around the airframe (aft of the CG, of course) with Wiffle Ball holes?


It might even whistle while going up!

Greg

1) Large, blunt nose
2) Base drag
3) Ring fin

-Kevin

krusty said:

A dress, lipstick and high-heel shoes. Oh, and a wig!

More drag than Mardi Gras :rofl:

Krusty

Click to expand...

Gives a whole new meaning to Drag Race...

?

I cannot agree with the idea to mess with the fin leading edges by adding a big thick bulb shape. This change could very easily destroy the smooth airflow over the fins that makes them functional and useful, reducing or eliminating the rocket's overall stability. If you have to use this strip of bulb-shaped material you could add it along the fin tips. Not sure that I recommend adding it to the fin trailing edges.

These are some good options:

troj said:

1) Large, blunt nose
2) Base drag
3) Ring fin

Click to expand...

You could try adding air brakes.

bobkrech said:

Drag disk. A removable disk that slides over the airframe with slots that allow it to slide about half way over the fins.

Bob

Click to expand...

While I agree a Ring is the easiest way to add drag even drag a ring could be too much drag.

Cutting 50' off a 3050 est altitude will need much finer control.
I would add a pair or trio of square tabs screwed to the bottom of the rocket flat to the line of flight.
Amazing drag. Bernoulli effect along with area.
I'm not sure how well Rocksim deals with these. A test flight would be best.

In all truth, More drag and less weight is far safer to fly.
Drop the weight and add the ring if you can.