Rocket

BY SECTION 15JEFFREY MCSHANEGHANGHOON PAIKCHELSEA WALKERTROY BUSHMIRE

NICHOLAS RAVAGO

Rocket shape analysis

Introduction

The experimenters of this lab decided that the analysis of rocket design, the various shapes of the nose cone, and the subsequent response in flight performance was of utmost importance to study. The same length of the rocket body and fin were used during the experiment. The team ana-lyzed four specific nose cone configurations:

1.) No Nose Cone (Flathead)2.) Blunted, Short Nose Cone (Taper)3.) Parabolic Nose Cone (Curved)4.) Apexed, Pointed Nose Cone (Pointed)

Nose Cone Configurations

1.) No Nose ConeThis Nose Cone configuration was selected to

provide a feel for the performance of the rocket with no aerodynamic performance. The team expected the rocket to perform with high drag characteristics, and the data was used as a basis for the other nose cones to compare to.


2.) Blunted Nose ConeThis Nose Cone configuration was selected to

allow a transition from high-performance nose cones to low performance nose cones. The team sought to detect how significant the length, shape, and size of the nose of the rocket was in determining lift and drag characteristics.


3.) Parabolic Nose ConeThe parabolic Nose Cone was studied in order

to view the likely performance of a rocket. The parabolic shape is quite common in rocket and missile design. The team expected that this model would have the best performance, as it was considered to be the most aerodynamic.


4.) Apexed, Pointed Nose ConeThis Nose Cone configuration was selected to

provide another look at a high-performance nose cone orientation, and how the lift and drag characteristics changed vs. the para-bolic nose cone.

Layout and Guidelines of Lab

The lab was prepared for an under-two hour completion of the study of multiple configura-tions of the rocket

The Hammond 2x3 Wind Tunnel was used with the ability to hot-swap the rocket in and out of the tunnel by un-hatching the tunnel window, unscrewing the rocket, changing the nose cone, subsequently adding a new nose cone, and then screwing the rocket back in.

The team used a pre-calibrated Force Balance attached to the computer for analysis

Lab Setup

Lab Setup Cont’d

The beginning of the lab required the lab group to dial up to 80% of the wind tunnel’s maximum airspeed. The purpose was to find a constant velocity to compare the different configurations.

The lab then consisted of using labview soft-ware to change the orientation of the Angle of Attack of the rocket from 0 to 20 degrees with increment of 2 degrees for all four con-figurations, while taking lift, drag, and pitch data for each configuration.

Velocity Calculation

Calibration of transducer B for constant wind speed (123ft/s)

Velocity of flow can be calculated with v = sqrt(2*q/ρ)

Constant voltage reading from the transducer will hold the velocity constant

Calibration was donein empty wind tunnel

Result and Discussion

Cd vs. angle of attack The flathead cone had the biggest Cd be-

cause it had a sharp and circular front edge, and the flow cannot smoothly traverse it. Similar results were found for the tapered cone.


Cl vs. angle of attackScattered results were obtained here, but the

parabolic head and pointed head were shown to have increased lift at higher angles.


Cm vs. angle of attackThe curved and pointed nose cones had the

smallest pitching moment because less forces were developed at the front section of the apparatus.


Cd vs. Cl of Flathead ConeThe results herein display a stable profile for

the drag coefficient vs lift coefficient for this rocket.

Conclusions

The results of the various nose cones are very similar to each other since only nose cones cause differences of lift, drag, and pitching moment. Flathead nose cones showed the highest drag, as expected. Performance of the curved nose cone obtained the best results as expected, however, the pointed cone had sim-ilar results. The tapered cone results ended up being between the flathead cone and curved cone which was expected.

Conclusions

The rocket is not the best shape to measure lift and drag, due to its shape. The length of the rocket body, shape, and number of fins were fixed variables.

The reason why the shape of nose cone mat-ters is that the nose cone is the part that di-rectly contacts the flow. The result is that the nose cone with the sharper end performs bet-ter than one with a flatter end.

Appendix

Lift, drag, and pitching moment coefficients of each nose cone is shown below

Curved coneCurved

AOA Lift Drag Pitch Cl Cd Cm0 -0.01342 0.164876 0.033553 -0.01669 0.205012 0.0417212 0.131706 0.156979 -0.18051 0.163767 0.195192 -0.224464 0.290495 0.164444 -0.36384 0.36121 0.204475 -0.452416 0.445138 0.226822 -0.3336 0.553497 0.282037 -0.41488 0.583499 0.232339 -0.51929 0.72554 0.288896 -0.645710 0.845365 0.316217 -0.64266 1.05115 0.393194 -0.799112 0.925668 0.358455 -0.75716 1.151001 0.445713 -0.9414814 1.086641 0.441441 -0.78743 1.35116 0.5489 -0.9791116 1.267787 0.518959 -0.92363 1.576402 0.645288 -1.1484718 1.387855 0.596088 -0.96498 1.725698 0.741193 -1.1998820 1.510503 0.657686 -1.036 1.878202 0.817785 -1.28819

Appendix

Flathead ConeFlathead

AOA Lift Drag Pitch Cl Cd Cm0 -0.07829 0.340346 -0.01096 -0.09734 0.423196 -0.013622 0.089569 0.311092 -0.16974 0.111372 0.386821 -0.211064 0.210936 0.322269 -0.34432 0.262283 0.400718 -0.428136 0.340799 0.355214 -0.3762 0.42376 0.441684 -0.467788 0.487408 0.39507 -0.49138 0.606058 0.491241 -0.6109910 0.752083 0.467414 -0.73548 0.935162 0.581196 -0.9145212 0.824544 0.488712 -0.8996 1.025261 0.607678 -1.1185914 1.050182 0.569156 -1.03118 1.305826 0.707705 -1.2821916 1.136913 0.650536 -1.06301 1.41367 0.808895 -1.3217718 1.310981 0.716218 -1.22985 1.630111 0.890566 -1.5292420 1.341584 0.790824 -1.27498 1.668164 0.983334 -1.58535

Appendix

Pointed ConePointed Cone

AOA Lift Drag Pitch Cl Cd Cm0 -0.05239 0.216162 0.139009 -0.06514 0.268782 0.1728482 0.142511 0.167649 -0.14828 0.177202 0.20846 -0.184384 0.273616 0.193282 -0.30395 0.340221 0.240332 -0.377946 0.374169 0.259466 -0.2673 0.465252 0.322627 -0.332378 0.585617 0.261312 -0.45998 0.728172 0.324923 -0.5719610 0.81324 0.331665 -0.61211 1.011206 0.412402 -0.7611212 0.901679 0.375675 -0.72726 1.121173 0.467125 -0.9042914 1.123197 0.467194 -0.8332 1.396615 0.580922 -1.0360216 1.283648 0.530715 -0.8988 1.596124 0.659906 -1.117618 1.470679 0.579615 -1.09789 1.828683 0.72071 -1.3651420 1.628306 0.644598 -1.16264 2.024682 0.801512 -1.44566

Appendix

Taper ConeTaper

AOA Lift Drag Pitch Cl Cd Cm0 0.029199 0.222616 -0.0476 0.036307 0.276806 -0.059192 0.146298 0.199215 -0.19484 0.181911 0.24771 -0.242264 0.315656 0.207472 -0.37539 0.392496 0.257977 -0.466786 0.452552 0.274597 -0.33531 0.562716 0.341441 -0.416948 0.588578 0.284752 -0.51243 0.731855 0.354069 -0.6371710 0.640941 0.281425 -0.51875 0.796965 0.349931 -0.6450312 0.973226 0.428626 -0.81393 1.210137 0.532965 -1.0120614 1.120306 0.490584 -0.8855 1.393021 0.610007 -1.1010616 1.288204 0.601095 -0.95788 1.60179 0.747419 -1.1910518 1.432834 0.66935 -1.11602 1.781627 0.832288 -1.3876920 1.517332 0.736974 -1.17653 1.886693 0.916374 -1.46294