Apollo AG-1 flight testing data

[Abid]

The Phase-I flight testing of my personal AG-1 will be finished probably mis next week. Here are some raw numbers we have gathered so far. These numbers are not at gross weight of 1232 lbs (560 kg). They are instead at 1100 lbs (500 kg). I have also not yet adjusted them for Standard conditions, which would adjust climb rate to be a bit better.

The conditions for the test were 80 deg. F, 5 knots crosswind. Runway in use: 36. Engine Rotax 914UL. Prop: 3-blade Sterna, Prop pitch: 16 degrees

Raw Data:
Climb Rate at 1100 pounds load: 1000 FPM, 65 knots
75% power cruise speed straight & level: 90 knots IAS, 87 knots CAS (5000 RPM)
Minimum airspeed without descending: 24 knots
70 knots at 3800 RPM (Correction: 70 knots at 4300 RPM, rotor RPM 360 - 370)

Engine parameters:
Oil temp: Too cold (needed covering oil cooler partially)
MAP: within limits
CHT: 167 F
Oil Press: Green

Rotor RPM: 370

Pre-Rotator: 220 to 260 RRPM reached fairly easily

Stick shake:
Very acceptable and fairly smooth with some rotor tracking through stringing and slinging and adjusting teeter block to center in the tower through use of feeler gauges. More load (bank) seems to reduce the shaking.

 

[ckurz7000]

Hi Abid, looking good on the flight testing. Glad to see you're taking it seriously.

Regarding reduction of data to standard conditions: There is a model in circulation that works for fixed wings. I haven't found one that could convince me in the case of gyros. That's why we verified all flight testing data predicated on IAS at actual IAS conditions in the ArrowCopter.

Greetings, -- Chris.

 

[jeff b]

70 kts at 3800 rpm is quite impressive. We are closer to 4800 rpm for that cruise speed.
You still have good climb performance too.

 

[ckurz7000]

Yes, the 70 kts at 3800 rpm is something I would try to get more data on. It is easy to over-/underestimate cruise speeds if you don't hold the VSI at EXACTLY zero fpm in a calm atmosphere with no up-/downdrafts. Particularly with a fixed pitch prop I doubt that 3800 rpm resulting in 70 kts cruise would be possible at a pitch that would also give you at least 5500 rpm static at take-off.

-- Chris.

 

[Fly Army]

Pretty good numbers. Almost as if you had a constant speed prop.

 

[Abid]

70 kts at 3800 rpm is quite impressive. We are closer to 4800 rpm for that cruise speed.
You still have good climb performance too.

Nope. Sorry. I wish that was not a typo. It is actually 70 knots at 4300 RPM.

Data from today (5 hours of flight testing, 1135 pounds, 78 to 81 degrees):
75 knots at 4600 RPM,
80 knots at 4800 RPM,
87 knots at 5050 RPM (recommended cruise at 4.5 - 4.6 GPH and quite comfortable),
and
Vh (max cruise S&L at max continuous RPM of 5500) is 105 knots (120 mph) ... started bowing the windshield at the top in front seat even though its a full 1 mm thicker Lexan than MTO. I am getting custom formed windshields done by a motorcycle windshield company here in Dade City, FL for US market. The prop they use in Euro models seems to not do what the prop I have can do or they don't really care to go there. The landing gear wing fairings did exactly as expected and tried for over 8 years by me in trikes. They start producing their own lift past 65 to 70 knots. One can actually see them suck upwards in flight.

Rotor RPM: 370


This was at 1135 pounds of weight in 78 to 80 degree weather with 65% humidity.
We temporarily disabled the dummy switch that only allows you to pre-rotate with the stick all the way forward for now because as Greg says, dummies shouldn't fly (LOL).
The rotors cannot hit the tail easily even at 100 RRPM with stick all the way back. They have to truly flap down to hit the tail.
We also added a small tailwheel at the back which completely eliminates any chance of any scrapping.

 

[Abid]

Pretty good numbers. Almost as if you had a constant speed prop.

This is a new prop from a composite manufacturing company. I am helping them with design and compliance. Very smooth and nice. Good composite execution.

 

[Brent_Brown]

Abid can you guys do a thrust test with that prop?

 

[Abid]

transposing the data to ISA

transposing the data to ISA

Hi Abid, looking good on the flight testing. Glad to see you're taking it seriously.

Regarding reduction of data to standard conditions: There is a model in circulation that works for fixed wings. I haven't found one that could convince me in the case of gyros. That's why we verified all flight testing data predicated on IAS at actual IAS conditions in the ArrowCopter.

Greetings, -- Chris.

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]

Abid can you guys do a thrust test with that prop?

I could.
However, just fyi that static thrust test does not tell you much about how the prop will perform on an aircraft even slow ones. Once you hit 30 mph, its completely meaningless really. It actually tells you something about engine power if you compare the same pitch, same prop on different engines for static run, etc.
Are you in need of a prop? If so which engine? If its in the 912 series, and you are close to here, you are welcome to come and I can install one and you can test fly it.
I still have to do what is called a vibration survey on it with representative engine (like on this gyroplane). Its a required item to get compliance as well as FAA cert.

 

[stupidceleb]

impressive numbers Abid!

What's your take off performance and climb rate like?

 

[Abid]

impressive numbers Abid!

What's your take off performance and climb rate like?

I have not done precise measurements of the takeoff roll yet. I wanted to allow Greg to get used to the feel of the gyroplane to get technique down to measure takeoff roll. The pre-rotator seems to be able to go to 250 very easily and very quickly. I believe there should be a triangulation at the pre-rotator bracket area to prevent resonance from happening which I will design and get made. Generally you'd do this in cam conditions in a set of 5 or 7 with markers, reject extremes and take an average of the rest that are more consistent.

The climb rate at 67 knots 2-up (1100 pounds) seems to be 1000 FPM but that's at 80 degrees. So for standard conditions where specs are supposed to be listed for aircraft performance (59 deg F, sea level), it would be more. However, I am wanting to set the gross weight at 1200 pounds or 1232 pounds if landing gear loads turn out ok which I believe they will so it will probably end right back near 1000 FPM or perhaps even 900 FPM at gross weight.

 

[Abid]

Looks like takeoff roll is coming to be 300 feet 2-up and climb rate at gross of 1200 lbs would be 800 FPM adjusted for ISA. Although I am beginning to agree with Chris that the model for adjustment for winged aircraft may yield not good results for rotary wings in the adjustment. So I have to really try and catch 59/60 degree F morning here that is clear. It was 60 F this morning but foggy and humid.

 

[Abid]

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.

 

[Abid]

Darren: I can't be completely certain w/o testing it on a 582 first but my educated guess would be that in performance and in noise level, it will do noticeably better. Greg has flown a lot with warp drive. My gyroplane I'd say to naked human ear sounds at about 65% of the noise level of Greg's Dominator. Whether it truly is or not, can only be ascertained by using a meter which I plan to borrow next week sometime from Sensenich Prop guys who are friends of mine. I will have a real solid answer about the noise then. You should talk to Greg to get his impression. He will tell you what he thinks about the prop without any regard for me, I am sure .

 

[Abid]

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.

 

[stupidceleb]

That prop sounds awesome!

Thanks for the detailed reports.

 

[Fly Army]

What's the useful load end up being ?

 

[Brent_Brown]

105 knots is 120 mph that is moving in a gyro.

 

[Abid]

105 knots is 120 mph that is moving in a gyro.

Yes but that is Vh at near sea level. Its not a practical cruising speed. I believe the enclosed version of this type of gyroplane can cruise at between 95 to 105 knots comfortably. I can see it is quite possible especially with a slightly different rotor blade profile