testing out twitter for the ru27 webpage
Archive for the ‘Flight to Halifax’ Category
So as you can see I created an account for RU27! I will share the account info with everyone so we can all speak for the glider.
This is a plot of ballast pump position for ru17 during its long duration test from December 2007 to January 2008.
This is a plot of ballast pump position for ru15 during its flight from NJ to Halifax. You can see that the ballast pump is way past the nominal value of +230 lots of the time. The plots of 17 look good. The plot of 15 looks bad.
This is the initial analysis of the data taken collected by ru15 on its trip to Halifax.
This is a plot of ballast pump (cubic centimeters) as a function of time. Note that the pump is measuring past it's specified position of + 230 cc. This could be electrical noise in the system while the glider is at the surface. Or could the ballast pump be actually at those positions?
This is a plot of m_battery as a function of time. You can see the voltage increase when we get into the gulf stream.
This a plot of m_depth versus time. The glider took some time heading out over the shelf in the beginning and then was in 100+ meters for the rest of the deployment.
This a plot of temperature measured by the ctd for the deployment. Most of the time in water < 10 deg C.
This a plot of temperature measured by the sensor inside the glider. The spike at the end is when the glider was sitting at the surface waiting to get picked up by the Halifax crew.
This is a plot of sci_water_temp in blue and m_vehicle_temp in red. The vehicle is a little warmer than the surrounding water.
This is a histogram of the pitch angle on climbs. The glider was at the optimal pitch angle the majority of the time.
This is a histogram of the pitch angle on dives. The glider was at the optimal pitch angle the majority of the time.
Shortly after the last blog entry, we had some surprizing news from RU15. On one of its descents, it looks like the buoyancy pump got stuck. RU15 was descending, and went below our normal working depth of 100 m.
Realizing it was approaching is maximum depth of 200 m, and it wasn't making any progress with moving its buoyancy pump, the robot decided to jetison its safety weight, and make an emergency ascent. When RU15 got the surface it phoned home and told us what happened. it would now remain on the surface and await recovery.
RU15 off Halifax. 53 days and 2600 km after deployment in New Jersey.
Strong currents to the west blowing us off the Halifax line. New waypoint set for offshore, HL3, perpendicular to the currents and back to the line.
We just completed a work week's worth of flight tests on RU15 while coming in along the Halifax line. Some watching closely will noticed that we slowed down a bit midweek, even though currents were slow. We were testing the buoyancy pump. Instead of pushing and pulling a full cup of water, we tried smaller changes in buoyancy to see how the energy savings would effect our flight characteristitics. Pulling in less water slows the glider and saves energy on the pump, but then it takes extra time to get somewhere so you burn energy just keeping the lights on. The tests will help us optimize the settings for long duration flight. We are now back up to full speed.
The deep basin off Halifax turned out to be an excellent test bed. Water over 100 m deep that is so close to shore. So we took advantage of the natural topography on the way in.
We are now half way between HL3 and HL2. We moved the HL2 waypoint a bit to the northeast so that it is in between the shipping lanes.
RU15 is now set to just bounce back and forth between the point between the shipping lanes and HL3. We'll keep this pattern going for several days.
We'll keep one eye on the battery and the other on the weather. Scott & Marlon have all the equipment for recovery and a boat ready when its needed.
RU15 made fine progress along the Halifax Line over the weekend. We are now 95 km from HL2. The SST image again highlights the advantages of an approach from the southeast. We are in the warmer water, that appears to head towards shore along this line and on the upshelf side. On the downshelf side of the Halifax Line, colder water appears to be heading south, against the direction we would want to head.
Currents remain low, 5 to 20 cm/sec.
RU15 hit the HL5 waypoint this morning and is now turned and heading towards Halifax inbound on the Halifax line. Currents are low, we are running about 10 cm/sec or less. About 140 km to HL2, so about a week.
Batteries still looking good, as far as you can tell. Time to settle into a scientific sampling section to go with the shipboard data currently being collected.