Today's Testing (4/24/2014). 4.75 hours
Morning 60 F but foggy, IMC and humid
Late morning 71 F, fog starting to clear to 1000 AGL ceiling, calm winds, takeoff roll was determined to be right around 300 feet at 1145 pounds with use of the pre-rotator on a tarmac runway.
Just above the clouds at 1500 feet MSL, several speed runs with engine RPM were done stabilizing the speed and leveling the aircraft with trim for 30 seconds or more before recording a reading. Yesterdays findings were confirmed for level speeds.
Its fairly easy to cruise at 55 to 87 knots very comfortably. At 90 knots there is some wind that starts to become a little bothersome for the back seat passenger. At 100 knots the wind for the back seat passenger starts to get uncomfortable but not so much that one has their helmet being pulled or anything like that. Just that one can feel the wind swirl in front of them. At 101 knots to 105 knots the front windshield starts to bow at the top. Given low levels of winds in the morning some preliminary verification of Indicated AirSpeed (IAS) was done against the Ground Speed shown on a GPS and it is expected that the error for Indicated airspeed to calibrated airspeed will be within 3%. A proper calibration chart for airspeed is to be developed this weekend following GPS method with tri-angular runs.
Talking to the guys in Europe, they cannot get 105 knots on their gyroplane using same installation with the prop they use. The max they can get is 98 knots. Their climb rate is slightly lower also.
Did a first cross country within the limits of the Op Limitations for Phase-I right to the edge. Engine performed flawlessly. The first signs of fuel starvation happened when the engine had coughed yesterday at about 1.4 US Gallons (5.2 liters) when on final approach, all the fuel went to the forward end and the fuel pickup for the engine which is at the back, sucked in some air and then when power was suddenly applied after touch down the engine coughed but regained fuel supply. That would have to be put down as unusable fuel.
Haven't talked to Bob Mackey yet but all Apollo trikes are specifically listed eligible for EAA's insurance so I do not think this will be a huge issue. I do not remember them asking me much about fleet size. They were more concerned about support and parts and US facility.Were you able to get insurance coverage for it? Typically they have a fleet size threshold.
Haven't talked to Bob Mackey yet but all Apollo trikes are specifically listed eligible for EAA's insurance so I do not think this will be a huge issue. I do not remember them asking me much about fleet size. They were more concerned about support and parts and US facility.
I am talking about reducing take-off and landing distance as well as climb figures. Doing airspeed calibration in non standard conditions is fine. This is simple thermodynamics with no regard of aerodynamics.Hi Chris:
I am going to be at the airport at 7 am tomorrow to get very close to ISA conditions if possible.
But why don't you trust the model for fixed wings for data to work for gyroplanes. Is it due to installation errors and static port errors more common in gyroplanes. I am doing a full calibration chart for airspeed every 5 knots to VNe.
P.S. Which model btw are you talking about for fixed wing data
Abid, I see just shy of 800 fpm at maximum gross. In the manual I quote it as 750 fpm to be on the safe side.For Chris:
I think I have the identical Averso Stella rotor blades as your machine. 27' 10" diameter, 8 7/16" chord.
Can you tell me what you see as climb rate in your testing on the Arrowcopter at 1200 pounds. It would be good to compare for a sanity check while I wait for a standard condition to occur in the ever increasing humidity mornings in FL.
My advice: spend a lot of time calibrating the ASI properly. This is what all subsequent numbers and speeds are based on.fara said:A proper calibration chart for airspeed is to be developed this weekend following GPS method with tri-angular runs.
Hi Chris:Abid, I see just shy of 800 fpm at maximum gross. In the manual I quote it as 750 fpm to be on the safe side.
I did many test flights to get this right. The key is to have an absolutely thermal free atmosphere. I wound up flying at 5 am in the morning, right at sunrise. Also, starting and stopping the stopwatch myself turned out to introduce significant error because of needing to fly a precise airspeed while watching the altimeter and managing the stopwatch. It can be done but probably requires a lot of practice to achieve good consistency.
At a climb speed of 1000 fpm your climb times for 500 feet altitude will be around 30 seconds. It's easy to make an error of 1-2 seconds starting and stopping the watch. That'll introduce an error in the neighborhood of 10% right there.
What worked out great was to use the data recording built into the EFIS. This records airspeed, altitude, VSI and time (among many other parameters). Then I used Excel to filter data and only use data in which airspeed was within +/- 2 kts over at least 250 feet of altitude. I also discarded data in which the VSI wasn't settled down yet (e.g., after pulling up into a climb).
If you don't have an EFIS, get yourself a 10Hz GPS data logger from an RC supply store (e.g. www.hobbyking.com). That's probably the best investment you can make for flight testing. You will get altitude, ground speed and VSI at 0.1s intervals. You still need to record airspeed but that's no biggie. Just keep it within 2 kts of target.
However, even weak thermals would muddle the data significantly. I am now at a point where I question climb data flown during the day.
I believe Arrowcopter makes their own prop.Does anyone know which manufacturer Arrowcopter uses for their 2 blade prop?
It looks highly twisted nearer the root and has the same tip design as the DUC and Prince P tip. I wonder about the noise their 2 blade prop produces?