Aero-Structural Update

The aero-structural team has been keeping quite busy recently as the whole design comes together. We are near the end of our design phase, transitioning into procurement and manufacturing. Here are a few of the main projects we are working on.

Cross-Braced Frames
The main structural components of the rocket are these 1' or 2' long frame sections. Modularity in the design makes it easier to manufacture, store, and transport. With the limited storage space we have available, this is an important concern. Currently we have all the material we need for the ring parts and cross braces (refer to the picture below). The picture does not show the array of holes for fastening or the fillet welds. We hit a snag with the c-channel parts when it became apparent that our supplier did not carry that stock. Currently, lighter c-channels are being analyzed using methods described in "Analysis and Design of Flight Vehicle Structures" by E. F. Bruhn. We did not even know of this book before and it has proved to be quite useful. Future revisions of the rocket could be more efficient, load bearing wise. Back to the present, we will get new c-channel in and get these frames machined and welded.



Nose Cone
The nose cone design is currently being looked after by Tom. Back in the day we had decided upon an ogive shaped nose cone, based on what we knew. Tom has been looking at different shapes and how they impact our performance.

One of the main unknowns that we had not addressed before was heating of the nose. We have always wanted a composite nose cone and we do not want it "melting" in flight. Temperature distribution over the nose cone is different depending on which shape we use and over the last week, temperatures have been estimated. Next week we plan to settle on a shape. The tip of the nose cone has always been an area of concern due to the fact that it will experience the highest temperature. There is also the problem of laying-up the nose cone by hand. None of us are carbon fibre experts so the quality of the composite at the tip may be sketchy at best. To rectify this problem, we plan on having a metal tip that threads into the rest of the nose cone. This should help with the temperature issue and should make manufacturing easier.

What has yet to be completed is a design for the internal structure of the nose cone. I imagine a simple frame that will help keep the shape of the cone and will make mounting to the rocket easier. Some of the recovery system will be located in the nose cone and mounting points are required for that as well. Insulation is important in the nose cone especially if we have a parachute packed neatly inside it. I like the spec's I see at the Aerogel website.

Fins
We have had a general shape and size for a while. We like the clipped delta configuration, slightly swept back, with a short span. We also have a nice stack of books, articles, etc. to look through regarding fins in supersonic flow, etc. Arash is working on completing the aerodynamic and structural design. For the fins we will also have an internal structure with a skin over top. Tom's heating analysis will determine whether we can use composite skin for the fins or not.

Other projects the aero-structural team is involved with include the fuel system and the rocket skin. The fuel system components have been spec'd and a BOM has been completed. Swagelok® is being contacted for most of our plumbing needs. Fuel system testing can be integrated with engine testing. The skin has been temporarily left on the back burner as the other major aspects are being completed. Several solutions have been proposed for attaching the skin to the entire rocket frame. This is next on the to-do list.

Ignition Update

Last week, Leigh helped me run some tests on the spark plugs that we got from NGK. The spark plugs that we tested are: R0045J-9, B7S, BM6F and BPR6EGP. It turns out that the B7S and BM6F work best. The next step would be to see how well they light up kerosene and liquid oxygen.

I recently finished drawing the augmented spark chamber with SolidWorks, and I hope to get it machined soon.

This is the augmented spark chamber that will be mounted on top of the main combustion chamber. The spark plug will be threaded into the spark chamber at the top, and small amount of fuel will be supplied from the side.

Launch System Update

The Launch Team is currently constructing a ~1/4th scale model of the rocket in order to test certain aerodynamic factors. We acquired materials last weekend and plan to start construction Thursday, with the goal of being finished next Saturday. The model has the same surface materials and shapes as Aurora 1, and will be used to find the aerodynamic stability margin by using the wind tunnel.

The Launch Platform design and construction is on hold so that people on the launch team can work on finishing the rocket. I believe this is necessary due to the launch system's dependence on rocket characteristics and performance.

I bought a small utility trailer and intend to use it to bring components from the Fraser Valley to UBC. This will be used to get the hydraulic system from Grecon, and possibly other components.

Recovery System Update

Our previous recovery systems manager, Guan-Lu, let Vitali take over this role. So, first the new work plan was composed to include tasks that need to be done by the end of spring and the deadlines for each of the tasks.

All the previous work done by the recovery systems team was organized and documented. Also the air brake design was finished. In particular, lug analysis was carried out for the joints on the air brake supports. What is left is to prepare the bill of materials for the air brakes and find an appropriate electro-magnetic actuator for the air brake release mechanism.

This Friday, Vitali and Angela had a meeting to discuss parachute design. We've formulated objectives to be accomplished by next week. We are going to keep researching parachute design and performance analysis. We will rely heavily on the book that Guan-Lu purchased for our team "Parachute Recovery Systems" by T. W. Knacke. This is an excellent book by the way, that provides us with very useful information. Also, the parachute design criteria list was composed. This list is to be used to add relevant information about the parachute design. Lastly, we found it necessary to try to find information on how cargo parachutes are deployed (this is not an easy task as the information of this kind is very scarce).

Meetings, Sparkplugs

A quick post as I am studying for a composites midterm.

Yesterday at our weekly team meeting, Winnie presented the sparkplugs that just came in. They are NGK models of various types (4 in all) ranging from cheap to high performance. We were planning on trying out all 4 with the igniter we've designed to see how they work, but we now realize they have different threads. Not sure how Winnie will decide to deal with that yet.


I've continued to work on the test site application - the form is filled out, and I've been talking every couple of days with the campus planning office. They pushed back our review meeting till March 8, which is next week, so not too bad. Provided they approve our application I think we can have the site erected by the end of March, which should coincide nicely with the procurement of other items needed for testing.

Finally, here's a photo of our meeting. We book the Dean's meeting room - it's got a nicer table and chairs than the other meeting rooms, although we have to bring our own projector.

Left-to-right: Winnie, Joel, Anna, Kirsty, Jon, Marco, Sebastian, Trian, Tom

Goings On

Some updates on propulsion and the team in general:

1. First, a number of other team members have been electronically invited to post on this blog. Nothing yet, it seems, but I'll keep prodding them to add their comments.
2. We are in discussions with UBC Campus & Community Planning about setting up a blockhouse on campus for engine testing. I have submitted our proposal and have the application form nearly filled out (waiting on two pieces of info from the UBC C&CP office). Along with this is a $350 application fee, but since we're getting the materials for the blockhouse donated (see below) it's not a bad deal overall.
3. We have a new supporter: United Lock Blocks will be providing us with their heavy-duty 5' x 2.5' x 2.5' concrete blocks for the engine test enclosure. Check out their website for all your concrete block needs - they have a variety of interesting concrete products. These blocks will mean that we can easily reduce most of the noise from the engine (the blockhouse will also be covered) and that "mistakes" will be less likely to result in flesh wounds or amputation. I'm also thinking that it would be a nifty place to take cover in the event of a nuclear war.
4. The launch team has a new project - wind tunnel tests. We have been trying to figure out how the rocket will behave in various cross-winds during the first few seconds of flight, so the launch team members (Mech. eng. students) will be building a scale model of Aurora-1 and running tests on it in one of UBC's two wind tunnels. Right now we're just making sure that our test procedure makes sense and that the wind tunnel simulation will be dynamically similar to the real rocket at launch.
5. We will likely become registered with the Canadian Controlled Goods Directorate. This is something I personally hate to do due to previous personal problems with ITAR (some rules made by our southern friends and neighbors), but it will be necessary for us to obtain a GPS unit capable of handling speeds over 515 m/s and altitudes over a certain limit. Once we're registered we can then go to a GPS manufacturer who can remove the locks on the GPS device. However, I'm guessing that being registered with the CCGD probably means difficulties for international student team members (UBC is lucky to have many international students, many in engineering). More on this as it develops.
6. Modeling of the combustion chamber in UniGraphics NX 3 has been slower than anticipated this week. This is because of my 3 assignments and 2 midterms, and having to spend time on all of the above. Unigraphics takes a while to learn, but is widely used in industry so I regard this as useful training.
7. Aluminum stock came in for our structural boxframes. The boxframes form the "backbone" of the rocket and will contain most of the avionics, helium tank, parachutes, cameras, valves, et cetera. Skin will be attached to the outside of the boxframes (it's not stringer construction - when it was designed we hadn't taken the aircraft structures course yet) and the boxframes will be bolted to the integral tanks. The boxframes will be easy to attach "innards" to, easy to work with, much, much stronger than they need to be, and able to withstand high impact loads, so they are a very robust design. However, I privately suspect that a monocoque composite structure might eventually replace the boxframes if we ever need to lose serious weight. Perhaps this comment will entice Trian, the aerostructures manager, into posting a rebuttal.
8. At our weekly team meeting on Wednesday (yes, Valentine's Day) I brought chocolates.
9. Greg D from the Canadian Association of Rocketry and the BC Rocketry Club has invited some of our members to the premiere of "The Astronaut Farmer" tonight and provided passes. I've been looking forward to seeing this movie - and this is definitely the best way to go! As a matter of fact, it's time to leave campus...

Propulsion Updates

The rocket currently under development by the UBCRP is called "Aurora-1", as named after a heated debate amongst team members. The "Aurora" part is pretty self-explanatory, and the number suffix will indicate the iterative version of the rocket (it is designed to be modifiable - more on that later).

The propulsion system, dubbed "Helios" (mainly because rockets have a special affinity for the names of ancient gods) is a 1500 lbf kerosene/lox engine. It has been under development for some time, a large part of which has been basic research and lots of reading in order to familiarize ourselves with engine terminology, history, and design methods.

We currently have the Excel model of the engine complete and I have been working on mastering Unigraphics NX 3.0 in order to make solid models. UGS has a bit of a learning curve but seems like it has a lot of capabilities. I recently learned that RocketPlane Kistler has decided to use UGS as well, which provided a little extra motivation for the continued use of this software.

In addition to working on UGS modeling, I have been working on getting UBC's approval for building a static test bunker on campus. After a discussion with the OHS manager, I am now on to Campus and Community Planning to obtain a land-use approval. It's proving difficult to get in touch with them - the "Special Projects Manager" position is vacant (anyone need a job?) and my phone calls to other members of their office have not been answered. I'll just have to keep trying the cold calls.

More update later.