Hello – it is great to have another builder! So far I really like the fuselage. It is strong and light with lots of space inside. Also it has a good aerodynamic profile. The kit is light weight and looks like a quick build. I am very interested in your mod ideas. Can you elaborate on how you plan to make those changes? It seems like a really good idea to mount the servos on the boom. Did you make any sketches of the mods you have planned? I would like to see what you have in mind. I saw a thread on this site for some guys that made a part to convert the wings to a “bolt together” design. They were attempting to make the whole kit break down like what you are going for. Getting the servos on the tail is an important step in that direction. Also I am interested in looking at the wing and considering cutting ailerons into them with servos mounted on the wing tip sections. This will greatly stabilize the flight for video.

Views: 2041

Reply to This

Replies to This Discussion

I have two more batteries now and a power meter. Soon I will be able to post some data on power rates and give details on the set up. Also I have pulled the 480 motor and attempted to slide the drive shaft out the other side and remount it without standoffs. The set screws stripped out so now I am working with an eflight power 10 and have switched the drive shaft to point out the side with the mounting holes. I will be running this one on a 40amp eflight speed controller to begin with as I have them laying around in my shop. Also I will be building a 4 battery in parallel wire harness to connect the 4 pulse 3S 2250 mAh Lipos to the speed controller. If all goes well I will have the data this weekend. I will go for a one hour flight this weekend. By the way bring a beach chair for the long flights.

Power system update: Motor is an eflight power 10; ESC eflight 40amp; batteries 4X2250mAh 3S Pulse, 2 45C, 2 65C, in parallel which yields 10,000 mAh; Radio, spectrum DX8, 8 ch receiver, T1000 telemetry which is reporting receiver voltage and Battery pack voltage (this will serve as my fuel gauge). Here is some preliminary bench test data: At full throttle 28.5 amps/341.6 Watts, 3/4 throttle 17.7amps/198.2 watts, 1/2 throttle 5.9 amps/72.3 watts, 1/4 throttle 1.8 amps, 22.1 watts, 0 throttle 0.3 amps/3.6 watts ( servo movement X2 of 0 throttle). This was just my first bench test and I only completed the power system set up and one bench test. Nest I will mount the electronics and batteries to achieve balance and then an endurance test flight.

Some bench top number crunching -

Battery in amp hours = 10; Power in amps at 50% throttle = 5.9 amps; time in minutes = 60.

Theoretical Flight Time: (10Ah/5.9Amp)(60minutes)=101.7 minutes

not quite,

your numbers are OK but,

you cannot get 10Ah out of a 10Ah battery , you may get 80% of that i.e.8Ah

The motor my be taking 5.9A but the controller is taking more that that as its powering the BEC, Rx, Servos and the ESC electronics. so you may be taking 7amps from the battery, less any heat loss in the wires , connectors etc.

Thanks for the feed back. I have seen the 80% factor befor but they were using it as a safety factor for a go around or two. Will discharging and charging the battery on the bench yield a more accurate Ah number? I must admit that over an hour and a half is a bit optomistic. I did get the amp number from a meter inline between the battry pack and the ESC, but no servo movement or heat waste factor. The telemetry on my radio will report real time data for battery voltage. I am planning to use this in the field as a "fuel gauge" and set the radio timer to 25% throttle for time. Hopefully I will have the electronics mounted and the plane ballanced for a test flight this weekend.

Cool paint I like the ACU pattern. Is that a camera mounted to the top?

Thanks I used a very cheap and inexpensive way to add the digital camo to the RQ-11 While also reinforcing the body at the same time.  My local hardware store carries different duct tapes with different designs so I cut out strips and pieced them together like a jigsaw puzzle.  Also I added 2 coats of clear sealant to give it that paint look.  Yes thats an action shot camera mounted to the top but can be moved around and locked into place.

No problem, it looks like you have it unders control .

The inline meter is the best way to go to get correct power consumption, Also consider adding capacitors to the input side of the ESC, they will reduce the apparant laod on the batteries and give longer duration and the ESC willnot work as hard.

I really like how you set up the servos for the tail wings.  Im using metal cables traveling through the tail piece into the fuselage where the servos are located kind of like a pulley system.

The RC radio gear is now mounted. I am using the specktrum DX8 with TM1000 telemetry system. The 4X2250 mAH batteries have also been mounted. The plane ballances well with the extra wieght from the batterys. Also there is still lots of space up front for a camera and under the ballance point for the 2.5 auto piolot. It is almost ready for an endurance test flight. 

Second test flight report: Weather conditions were: 6-15 mph wind coming in steady off of the ocean, late afternoon sun, partly cloudy sky, and about 68F. Total flight time was 91:24 minutes. The Spektrum DX8 with TM1000 telemetry radio provided real time flight time and battery pack voltage. I used this data as a “fuel” gauge to monitor the battery pack. Fully charged the TM1000 reported 12.5 volts. My flight plan was to climb out to 300’ throttle back to 50% and circle until the battery pack was at 10.5 volts and then land. The flight time goal was 60 minutes. After reaching circling altitude I throttled back to 50%. The raven was still fast and climbing so I throttled it back to 47-48%. This was enough to penetrate the wind and keep from stalling. After circling for 60 minutes the pack was about 11.6 volts so I decided to go for 90 minutes. After reaching 90 minutes the battery pack voltage was 11.1 volts. I got up from the beach chair and throttled up to fly her a little before a pass to size her up for landing. With the extra batteries she was coming in pretty fast.  The beach sand makes for a forgiving landing. Into the wind throttle back slight flair and a 10’ gentle skid (this time I covered up the vent hole in the nose). Battery charging data: 1) 2129 mAh, 2) 2153 mAh, 3) 2097 mAh, 4) 2203 mAh; average = 8582/4= 2145.5. Average % used = 2145.5/2250(100) = 95.35%. The ESC had not reached cut off so it appears that these batteries will yield 2250 mAh of usable flight time. The battery packs discharged evenly but not perfect. One of them yielded 2203 mAh. Since I could not see each pack voltage it would be possible to over discharge a battery as the telemetry is reporting the 4 batteries in parallel. Conclusion: the current power set up far exceeds the flight time goal of a one hour flight time and the air frame is able to handle more payload weight. Next step is to procure and install the auto pilot. At the current wing loading the wing is beginning to feel weak to me. I am not confident that the wing could withstand 100% throttle and 100% control inputs with the current payload. I was very gentle on the stick during this flight.

Reply to Discussion

RSS

© 2019   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service