The U.S. Army has a new spy plane which is a repurposed DeHavilland Canada Dash 8. You can read a bit more about it here: https://www.thedrive.com/the-war-zo...rmys-powerful-new-ro-6a-spy-planes-will-carry I discovered this by accident looking at someone's instructional youtube video. I chanced to notice a plane flying around in circles. I was able to catch the ADSB code and flight identifiers: AE5C8F / R50338 This aircraft is currently based out of Manassas, VA. Here is one flight it made a few days ago: https://flightaware.com/live/flight/R50338/history/20200418/1828Z/KHEF/KHEF In this flight the airplane heads straight out to New Jersey. I've started to analyze spy flights and found a few interesting features of this mission. First, upon arriving in New Jersey the aircraft spends several hours flying a perfectly circular ~20 mile course, retracing its ground path over and over. Also we can see that there are some reversals sometimes flying a right hand circle and sometimes flying it to the left. Another feature that I though was a bit unusual about the above flight is that while circling, the airplane's airspeed fluctuates in a sine wave pattern. I guess the intent is to maintain a consistent ground speed? In this case we see air speeds ranging from 254 - 152 mph. From this I conclude that the target ground speed is the average of the two: 203 (maybe the target is an even 200 mph? 176 kts. The airplane's fastest air speeds are when the headings are SE and the slowest air speeds are when the heading is NW. If I'm correct, I might conclude that the winds aloft at the time of that flight (Saturday 4/18/2020) were 51 mph out of the SE (254 - 152) / 2. I tried to find historical winds aloft from the National Weather Service but they are only forward-looking. I did notice that in this flight they were circling first at 10,000, then 15,000 and finally 20,000. Each time the altitude was raised the speed range increased which implied to me that they were encountering stronger winds aloft so they were trying to compensate for this by varying their speed more. Actually this plane just concluded a 3.5 hour flight flight over Roanoke, VA, landing two hours ago as of this writing. They flew a circular path at 10,000'. The speed range in the circle was 113 - 274 mph. That would make the average ground speed be: ((274.0 + 113.0) / 2.0) = 193.5 and their apparent winds aloft would be: ((274.0 - 113.0) / 2.0) = 80.5 mph. The current winds aloft for Roanoke VA at 9000 feet is 29 mph, from 300 degrees (a bit east of SE). I may be making an improper conclusion that they are trying to maintain a constant ground speed because 29 mph is pretty far off from 80.5 mph. Or maybe its my crappy math assumptions! strat-o
Hi Strat-o Saturn Arcs have been into the UK using callsign GRZLY. GRZLY76 note last to digits match 16-00276 AE5F19 passed through Prestwick on the 16/4/20. I'm working on tie-ups at the moment for 7 airframes... There maybe more. Will post when I have collated the data. Regards Keith
Good info Keithdr. I live in Houston TX. It seems like it is spy plane central around here although none of the RO-6a's here so far. I've been compiling a list of tail numbers that I will post here. I'll post my favorite: N956TX operated by Texas Dept. of Public Safety. This is a Cessna 208 Caravan that has a veritable forest of antenae on it's underside. (Do a search on it and have a look!) About 6 months ago it was doing flights where the circling was computer crisp. Each orbit was exactly over the previous one just like what I was seeing from these recent RO-6a R50338 flights. I would assume that they have a computerized auto pilot being used. More recently we are seeing that the circling of N956TX is more hand-flown evidenced by their more imprecise appearance. I looked up GRZLY76 and see that it is a Dash 8, RO-6a, in fact. Is GRZLY an RO-6 as well?
I noticed that flight Saturday, I see so many training flights over NJ that I didn't pay it much thought, but did look up the aircraft type since it was listed as an Army plane and wasn't a type I had seen much of before. I'm guessing they are doing training runs over the McGuire-Dix-Lakhurst joint base Looking back through the database on my 2nd raspberry Pi it has been making about a flight a week since my database was last reset in January.
The graph you see on FA or FR24 is not airspeed, it's ground speed. Ground speed is the primary speed transmitted by ADS-B. Airspeed data is transmitted less often and only if the interrogating radar requests it. Use our history, it even has some airspeed data (the indicate airspeed reading that sometimes appear seems false, but the true airspeed transmitted seems fine). Click on a point in the trace to place the aircraft there, then start the playback for example at 20x https://tar1090.adsbexchange.com/?icao=ae5c8f&lat=39.981&lon=-74.532&zoom=10.2&showTrace=2020-04-18 True airspeed seems to be fluctuating between 170 and 180 knots. Anyhow ... it's flying a perfect circle in reference to the ground, the autopilot is probably set to speed and altitude hold. So due to the wind the required bank changes and requires more or less power, so i would expect the airspeed to fluctuate a bit as well.
It was back over NJ today, headed back at about 10pm. Instead of a circle it was doing straight lines just south of Philly. Looks like the line is magnetic east-west for this area, but that could be just a coincidence.
