09 November 2008
CDR Update
11 Nov 08 00:20
Breaking it down...
-After a few iterations (and constructive arguments/team bonding), we built a prototype of the DM. We started with an acrylic material design that had manufacturing defects and moved on to a low-tolerance aluminum design. Thanks to Jason for getting that done! The final DM design has evolved into a variation of the pin-sleeve design we settled on at PDR. It came down to the predicted mechanics of the release.
-Michael built a great release model in MATLAB that gave us a design space for SV placement. Some features of his model: PV-SV collision detection; thrust and elevon deflection as a function of time; relative PV-SV positions; graphical representation of the SV and PV; and, because he could, a "percent analysis complete" display. Unfortunately, we've run into some trouble with PowerFLOW and cannot run the necessary simulations. Jeff is working hard on this!
-We have a preliminary model of the PV-DM interface in ANSYS; Jeff completed a three-point load test on many pieces of balsa wood and plywood for the modulus constants in this FEM model. Scott is currently working out how to simulate the in-flight loading scenario.
-The analysis of the maximum lifting capacity for the SVs has been completed and the final design space of the SV power system will be known this week It's really a matter of plugging in new numbers, pressing F5, and calling it good. We have also been looking into sensor packages -- an HPT package or a wireless camera -- although this is a stretch goal for the SV. Work has begun for the Electrical Design and Interface Document (EDID) and Software Design Document (SDD). Most components are known and all that remains to do is a set of comprehensive block diagrams at the subsystem level.
-With a COTS plane, we needed data concerning the motor thrust as a function of battery current, as the main driver of the SV power system design is the 15-minute endurance requirement. We contacted Professor Dale Lawrence, who has experience with this type of test. He was kind enough to let us into his Guidance and Control Lab to show us the setup he used for the Stryker, a COTS aircraft that Bill Pisano used for his CUPIC testing and verification. Professor Lawrence has a 6-DOF load cell with sufficient accuracy for our needs and coordinated with us to use this setup for dynamic thrust testing in the ITLL wind tunnel. He also needed to complete some more testing for his unit and decided it would be more efficient to do his testing and our testing on the same day. Jeff got his hands on the Superfly (our chosen COTS SV) and cut it up to fit in the wind tunnel. We are nearly ready to plug and chug with the test! Jeff also contacted Trudy Schwartz and obtained approval for wind tunnel testing to will begin tomorrow (Sunday) afternoon. This data will be put to great use: Error bars! Big thanks to Professor Lawrence for helping us out.
-Travis has been in contact with our RECUV pilot, Tom Aune, and has completed the selection of the PV RX/TX system and engine-fuel combination.
-Frank "the RC guy" was also kind enough to perform some flight tests with the Superfly. He did some static thrust tests and endurance tests. He confirmed our analysis on several fronts: We calculated several flight dynamics/stability parameters and Frank verified these; we calculated a new lifting capacity, which Frank also verified. Thanks again to Frank!
These next three weeks will be surely be "fun." :D
Posted by Matt Lenda
-After a few iterations (and constructive arguments/team bonding), we built a prototype of the DM. We started with an acrylic material design that had manufacturing defects and moved on to a low-tolerance aluminum design. Thanks to Jason for getting that done! The final DM design has evolved into a variation of the pin-sleeve design we settled on at PDR. It came down to the predicted mechanics of the release.
-Michael built a great release model in MATLAB that gave us a design space for SV placement. Some features of his model: PV-SV collision detection; thrust and elevon deflection as a function of time; relative PV-SV positions; graphical representation of the SV and PV; and, because he could, a "percent analysis complete" display. Unfortunately, we've run into some trouble with PowerFLOW and cannot run the necessary simulations. Jeff is working hard on this!
-We have a preliminary model of the PV-DM interface in ANSYS; Jeff completed a three-point load test on many pieces of balsa wood and plywood for the modulus constants in this FEM model. Scott is currently working out how to simulate the in-flight loading scenario.
-The analysis of the maximum lifting capacity for the SVs has been completed and the final design space of the SV power system will be known this week It's really a matter of plugging in new numbers, pressing F5, and calling it good. We have also been looking into sensor packages -- an HPT package or a wireless camera -- although this is a stretch goal for the SV. Work has begun for the Electrical Design and Interface Document (EDID) and Software Design Document (SDD). Most components are known and all that remains to do is a set of comprehensive block diagrams at the subsystem level.
-With a COTS plane, we needed data concerning the motor thrust as a function of battery current, as the main driver of the SV power system design is the 15-minute endurance requirement. We contacted Professor Dale Lawrence, who has experience with this type of test. He was kind enough to let us into his Guidance and Control Lab to show us the setup he used for the Stryker, a COTS aircraft that Bill Pisano used for his CUPIC testing and verification. Professor Lawrence has a 6-DOF load cell with sufficient accuracy for our needs and coordinated with us to use this setup for dynamic thrust testing in the ITLL wind tunnel. He also needed to complete some more testing for his unit and decided it would be more efficient to do his testing and our testing on the same day. Jeff got his hands on the Superfly (our chosen COTS SV) and cut it up to fit in the wind tunnel. We are nearly ready to plug and chug with the test! Jeff also contacted Trudy Schwartz and obtained approval for wind tunnel testing to will begin tomorrow (Sunday) afternoon. This data will be put to great use: Error bars! Big thanks to Professor Lawrence for helping us out.
-Travis has been in contact with our RECUV pilot, Tom Aune, and has completed the selection of the PV RX/TX system and engine-fuel combination.
-Frank "the RC guy" was also kind enough to perform some flight tests with the Superfly. He did some static thrust tests and endurance tests. He confirmed our analysis on several fronts: We calculated several flight dynamics/stability parameters and Frank verified these; we calculated a new lifting capacity, which Frank also verified. Thanks again to Frank!
These next three weeks will be surely be "fun." :D
Posted by Matt Lenda