PMR-TARC14

As I mentioned in my TARC projects intro this rocket is already complete and has flown "successfully".  I am only missing two components for it to meet the competition requirements, an approved altimeter and the foam to protect the eggs.  As far as the technical  work that remains to be done, i need a reasonable estimate of the drag coefficient so that I can start to develop a model to determine how much ballast I will need to add to hit the target altitude.  I am also going to try to see if I can predict the variability of the motor based on some parameter that I can measure out in the field.
Since I am already well over a year behind schedule for this project and am running concurrently with my 2015 project the following table is quite an aggressive flight schedule based on the fact that I will probably have a whining, but cute, 4 year old dividing my attention from every thing that I am trying to accomplish. All in all I am very excited to get this project going again

TARC 2014 Planned Flight Schedule

Flight #	Configuration	Motor	Objective	Date
1	No Egg/No Alt	E18	Stability Check	7/5/2014
2	No Egg	E18	Estimate Cd	3/2015
3	No Egg	E18	Estimate Cd	3/2015
4	Full	F39	Full System Test	5/2015
5	Full	F39	Qualification 1	5/2015
6	Full	F39	Qualification 2	6/2015
7	Full	F39	Qualification 3	6/2015
8	Full	F39	Competition 1	7/2015
9	Full	F39	Competition 2	7/2015

PMR-TARC

I know that it has been awhile since I posted anything here but honestly that is mostly because I have not had much going on with my rockets other than a few launches and lots of repairs and lamenting that they are incredibly difficult to store.  That has changed over the last 18 or so months after I rediscovered TARC.

The Team America Rocketry Challenge (TARC) asks students in grades 7-12  to build and fly a rocket to a specific set of requirements that changes every year.  The competition is designed to test the students ability to preform all of  the major tasks of a large scale project.  Then the participants are scored based on achieved altitude and flight duration with the winners being selected to compete for some fairly significant prizes.  So I decided to try my hand, unofficially of course, at the TARC as a new and interesting challenge and to focus my hobby a bit more than just collecting more rockets.  Plus I figure that with my education and experience with model rockets I should be able to be competitive with the top teams.

Currently I am working on two TARC projects one for the 2014 competition which has now concluded and one for the 2015 competition that Is just getting underway.  My plan is to document my projects here as they progresses. 

PMR-TARC14

Length: 28 in

Diameter: 2.2 in

Dry Mass: 242.6 g

Payload: Two raw jumbo eggs 123 g

Motor Mount: 24mm

Motor: F39-6

Target altitude: 825 ft

Target flight time: 48-50 s

Electronics: The rules require a Perfectflite PNUT but I will initially be using an Estes altimeter.

Recovery: 2x  20" nylon "custom" parachute.

Some interesting features on this rocket include the fins, which I made out of plywood for strength with balsa inserts to save on weight. This will be my first use of a F impulse motor, as well as personal use of electronics.  To-date it has flown only once, which was mostly a success.  Only one chute deployed and there was no payload.  It was mostly a flight to check the stability, but I enjoyed it and nothing broke so, success.  I have lots more testing planned and am waiting on funds and launch dates to move forward, which likely won't be until spring. 

PMR-TARC15-EMS

Length: 31.5 in (26.5 req)

Diameter: 2.6 in

Dry Mass: 521.3 g

Payload: One raw large egg 60 g

Motor Mount: 24mm

Motor: F39-6

Target altitude: 800 ft, 775 ft

Target flight time: 46-48 s, 45 -47 s

Electronics:  Perfectflite PNUT, Pro Micro from Sparkfun electronics, HS-55 sub-micro servo.

Recovery: Payload and booster recover separately  probably on  20" nylon "custom" parachutes.

This is by far a more ambitious project.  My approach for the 2014 rocket and indeed the approach most people use for this type of competition is to chose a motor that will get the rocket close to but above the target altitude and then add mass to adjust the final altitude.  This presents a unique challenge for the 2015 competition because when the top teams do their second flight at the finals the target altitude changes from 800ft to 775ft.  Just add weight and your good, but to be successful they will have to do more practice flights.  
So what is my plan?  I am going to scale down the Energy Management System (EMS) that the USU Chimaera Rocket team used in 2009 to win the NASA USLI competition.  The Perfectflite PNUT altimeter is capable of streaming telemetry, current altitude, to some other device.  I plan to feed that data into a micro controller and have it actuate a servo that will deploy air brakes at the base of the rocket.  While the use of the micro controller probably violates the rules i think that it will add an interesting challenge for me and if it works I won't have to add any mass to the rocket and have a perfect flight every time. 

Christmas has allowed me to start collecting parts and I hope to have this one ready to fly in time for Southern Thunder in late June. Time will tell however if this is just a pipe dream.