First Pilot baseline power tests - a rainy day in Woodside

We conducted the first Pilot baseline power tests at Canada Road in Woodside on Saturday.  We started with a limited number of pilot/riders because we knew the first time through there would be some glitches, and we wanted to learn from that.

The biggest glitch turned out to be the weather -- mostly blue sky at my house in Santa Clara at 7:00 a.m. and limited radar returns unfortunately did not equal no rain in Woodside at 10:00 a.m.

We decided to soldier on and try to get some data to at least make this "dry" run worthwhile for helping our tests in the future run smoother.

We found we had some issues with the pedal swapping (frozen pedals on the diamond frame bike, and reversed pedals on the funky reverse pedaling recumbent we had at our disposal), so that will get fixed before the next round of testing next weekend.

We also learned that most people are not familiar with the recumbent position at all, and that made it difficult to ride hard.  So we will offer some practice rides a few days before the tests so people can get more comfortable before doing the ride.  (We are also testing in both upright and recumbent positions so we can find the true power output of people who are not yet comfortable with the recumbent position.)

We confirmed that the course is a good one for a short time trial to determine power levels, but also determined that if you are soaked to the bone for 2+ hours, that time trial is not going to be a very fast one! :-)

Onward to next weekend, and a hope for dry weather! (we will cancel next time if it is this rainy).

One of the riders had a good time trial before things became too wet and cold and everyone else had a sub-par performance.

Test Trike up and running

I received a big box at my house last week that contained the trike, and a small box courtesy of Quarq that contained our power meter.

After I brought it to our work space, we met on Wednesday 2/16 to discuss how we are going to turn this into a test trike for testing our drivetrain including prop, and our avionics.  Whiteboard scribbling ensued:

We then proceeded to tear the bike apart and get it almost put back together with the new power meter, but we were missing a bolt and a spacer.

Later in the week, we got the missing bolt and installed it (and even later, the spacer to take out the side-to-side slop).  Tom got the Ant+ receiver working, and integrated it with the realtime display on Golden Cheetah so we could see realtime data coming off of the sensor.

Now, we just need to finish the design of the new parts to add to the trike, do some cutting and welding, and prop testing fun will ensue.

More pics of the trike are available here:  https://picasaweb.google.com/alec.proudfoot/14Feb2011_DaSH_Trike_and_powermeter#

Alec

New Trike

Modifying the trike to become our propeller and drive train test bed.

Constructing the prototype propeller

Constructing Propeller 1

Why we're doing it

Alec on why we're doing it.

9 more work tables finished!

Tonight a dozen people made short work of 9 more work tables (joined into 3 long 24 foot X 4 foot tables).  We finished 9 tables in the same time it took to make 3 a few weeks ago.

Now it is time to build some plane parts!

A Whole 'lotta Wood

Tom and I bought all the wood and supplies to build 3 more work tables for DaSH (the same table design as this: http://picasaweb.google.com/alec.proudfoot/30Dec2010_DaSH_Work_Table?authkey=Gv1sRgCIfs3bia5vH5mgE#5558045266940278658 )

It was a LOT of wood.  Just buying it, transporting it, and unloading it took about 5 hours.

I look forward to seeing everyone who can make it at the table build on Thursday night 2/3, starting at 7:30 p.m.!

If you plan to make it, fill out this form so we know how many people to expect.  (Will take 5 seconds, just list your name:  https://spreadsheets.google.com/viewform?formkey=dGRpWUthTkxFOTdDVXJrZGpqZGdOMmc6MQ )


-- Alec



P.S.  All photos:

http://picasaweb.google.com/alec.proudfoot/JanFeb2011DaSHTableBuild#

Airfoil Laser Cutting tests

On Wednesday night, 1/26/11, Matt and I did some laser cutting tests with various materials.

We tried Spyder foam (a form of dense, anisotropic blue styrofoam), to see if we could possibly use the laser method to cut out many thin sheets that we could stack up to make our next propeller.  The laser cut a very precise shape on the surface, but the heat caused an undercut, scalloped edge.  So that method probably wouldn't work too well for stacking many sections on to build up a prop.  However, it is possible to cut foam if we aren't too concerned about the exact dimensions (or only want exact dimensions on the skin and undercutting is what we are looking for on the rest of the part).

However, the laser did a fantastic job of cutting out balsa wood (as previous tests had shown), and also thin spruce plywood -- we tried both 1/32 and 3/32" sheets.  The plywood is perfect for making templates that can then be used to hot wire cut foam for the propeller and for the main wing (we will need to get creative about joining template halves for the full wing templates, since we are limited to a 24 inch working area, and our wing chord for the airplane is likely to be 4 feet or greater...).

We also tried cutting out keyways in the balsa wood ribs.  If we built another built-up wood prop, we would probably use this method to make the alignment of the ribs much quicker, easier and more precise. However, our next prop will probably be foam as described above.  (The spruce keys shown loose here would be glued to the side of the spar in practice).

More photos are available here:

http://picasaweb.google.com/alec.proudfoot/26Jan2011_DaSH_laser_cut_tests#

-- Alec

First Hardware!

Saturday night, 15-Jan-2011, we finished our first DaSH hardware -- prototype prop blades (designed for a 16 mph aircraft -- we still need to finalize the aircraft layout, wing area and speed).

Tom holds the finished propeller blades

We had a lot of fun building these and learned a lot about how to build it better then next time.

These props were built up from Aluminum spars, balsa wood ribs and sheeting, and spruce secondary spars.  We probably won't build the "final" props this way -- more likely they will be built with foam covered by light fiberglass cloth, with either an aluminum or carbon fiber spar.  But these props are fully functional and should work, and they actually aren't too heavy.


Final stats:

- 1.227 kg (Blade A -- 0.6113 kg , Blade B -- 0.6157 kg, 4.4 grams apart)

- 193 man hours 

- 2 weeks build time (1/1/2011 to 1/15/2011)

 
To view more photos of the build, go to:  http://picasaweb.google.com/alec.proudfoot/2Jan2011_DaSH_proto_prop_build#