I redesigned the unit to accommodate a disc shaped fuselage.
Smaller unit is a big challenge to successfully balance in the air. Currently the servos are compensating at a very high rate. Disc shape is not something that I tested before. I am a little concerned about the aerodynamics of the forward flight.
Got high discharge batteries. Hoping to test it successfully, finalize PID and re-create a nano version of the Avrocar.
The avrocar project hasn't been very successful with the initial design. There was something very wrong with center of gravity that needed to be addressed. I couldn't eliminate the toilet bowl effect with my existing and new solutions that I tried.
Made a revision on the body to fix the center of gravity problem. Flies way better now and the toilet bowl effect was reduced. However, it didn't disappear. Below videos is an outdoors test, which started good but didn't end very well, with the unit losing the flight capability with a fatal wobbling.
Damage was minimal and the unit is fixed. Next step is switching from 1 battery to 2 batteries, increasing the weight and therefore increasing the effectiveness of the thrust vectoring.
All challenges resulting from the characteristics of this unique design is being magnified as the size goes smaller
Great experience to learn the limits of the design!
The new battery configuration made a huge positive difference, combined with the longer fan body.
I also upgraded the ESC by adding a mini heatsink on it, to handle the extra weight (originally it is a superlight multirotor ESC ).
Even though I built this for indoors, I felt comfortable enough to test it outdoors. There is a slight steady wind but it didn’t stop me. This is only a balance and flight time test and I just kept hovering against a headwind but I felt comfortable enough to take it around the park if I wanted.
The first flight videos with the new outfit. The new design restricted the airflow a little bit and added about 7 grams. This resulted in a reduced flight time, not using all the juice in the batteries offered.
So, I turned the batteries to 90 degrees to the fan axis to provide better airflow and lowered the cover to increase the airflow. You will see the pics of this configuration before the second flight. It helped but the unit still didn't complete the previously achieved flight time of 3+ minutes.
Next phase will be working on the cabling and some other things to reduce the weight and make the unit more efficient, and maybe try to find some tricks to increase the lift.
If not successful, will need to find a different solution to the looks
Looks pretty good from here. Have you ever attempted tooling around with thrust tubes (other than the vectoring) for increased exit speed? I took some Phase3 F16's to 80% and 70%FSA at 2.5 to 3x shroud dia. in length and it makes a ton of difference. This also pulls alot more amps though.
Anyhow, just curious. Merry Christmas!
I don't have a short temper. I just have a quick reaction to B.S.
Thanks for the input birdDog! Yes the playing with the exit diameter was something that I tried a couple of times before. However, as you say, it will pull more amps and the ESC may not handle it and I don't want to go to a heavier ESC. Also that solution will reduce the flight time. Dealing with the Vertical EDF concept for a while now, I found out that the best solution is usually the one that reduces the weight and increases the efficiency. We'll see how it comes around. Merry Christmas!
This is the new minimalist design! I decided to call this one the mosquito. It looks very much like one on the flight video.
The other improvements that I made was, making some of the cables shorter, getting rid of some bullet connectors, etc... to make it lighter.
The reason of the surface at the front is to create some lift during forward flight. It tilts forward and will give it a little uplift. I will see if I can get close to 3.5 minutes or more with forward flight.
Again, there is a pretty strong wind for this size unit but handles it well. Looks like the flight time got up to 3 min again. One thing that I need to be careful about is not to fly it backwards too fast. This is what I did at the end of the video and t kinda lost balance.
I will also increase the yaw rate and make it more responsive for tighter maneuvering.
Ok. This is the final design. It looks phreaky sweet!!! Below is a combination of a couple of flights. After the first two, I replaced the thrust vectoring nozzles with new and larger ones. The reason is that when I fly it backwards, it gets into a cyclic motion, losing altitude. I didn’t have this problem in larger units.
Large nozzles are more responsive, so it is a little wobbly in the last flight, requiring the P rate to go down a little. So, will test it tomorrow again with the new P setting to see how the new nozzles perform.
There are some close-ups in the flight video that show how the nozzles operate.
This is the first aerial video of the 40mm unit. I am using a CM205 camera with RC305 receiver and easycap AV USB converter to record it on my computer.
The cam is a little crooked and the resolution is not all that good but not bad for the first time. I am still learning the settings on the easycap and I should be able to get a better resolution. We’ll see…
Completely re-designed the Nano. Replaced the old 3S fan with a new higher kv 2S fan. Results are nice. Never felt so confident flying the Nano before. Have a problem with the power setting tho. The unit is still cutting off power during the flight…
I had some electric problems with Nano. Towards the end of every flight, the flight controller shut down and I had some rough landings. So, I doubled the UBECs, increasing the power to 6amps but at the end of the first flight in the attached video, the unit shut down again and crashed. The new fan is amazingly powerful but pulls more amps and I think it towards the end of the flights it has been causing the voltage drop to a level that the FC had to shut down. Fortunately, didn’t have a significant damage. This time I changed tactics and added a tiny 2s lipo to the equation, powering the servos and the cam, and took out the second UBEC.
Bingo! I was able to use the last drop of juice in that battery in the second flight. With only one problem. At the beginning of the flight the new added battery came off after takeoff, hanging down from the unit. Amazingly, the unit balanced itself and I was able to land it to get ready for the last glorious flight
This unit is amazingly well balanced and flies very well… Fun stuff.