First off I just have to say, I submitted this as an article on the FT main web site and I have been waiting for a week to get it approved. To be honest, I just got tired of waiting. Thats when I started looking around on the forums here for the first time and found someone had a similar issue and was told to just post it to the forum. So this is pretty much an exact copy of my article that's still waiting for approval. I hope you guys like it!
When I watched the "Let's Fly" video for the Blunt Nose Versa I noticed this HUGE gap between the control surfaces and I instantly knew I had to do something about that so I went in the shop and got to work.
While building this thing I remembered a video where a guy (MyGeekShow) tried to use thrust vectoring to act as a kind of "rudder" on a delta wing and my mind went to differential thrust. I didn't have all the details worked out for differential thrust by the end of the build but I went and maidend my creation anyway without it. It flew really nice and was very stable from the beginning. A little trimming was all it took and it was good to go.
After the maiden, and a few additional successful flights that day, I came home with the idea of using differential thrust on my DX6i still nagging in the back of my mind. So I hopped online and did some digging and came across an article (and I really wish I could find it again so I could give the guy credit) where someone suggested using a v-tail mixer since the DX6i has some kind of issue with binding differential thrust to the rudder channel. So I ran out to the shop and threw it together using a v-tail mixer.
I have added some pictures of my work and a video at the bottom demonstrating the differential thrust. Please comment and let me know what you think. Also, I'm very new to the RC hobby so any suggestions would be great!
I put the esc's as far forward as I could get them to help balance out the weight of having two motors in the back.
I'm pushing the Blunt Nose Versa with a pair of Suppo 2208/14 1450kv motors swinging 7x4 props. (Not the cw and ccw 8x4's shown in this picture)
I used magnets to hold the hatches shut and nylon control horns for handles.
I'm running everything on two 3s 2200's in parallel with that adapter and wire mess.
To get differential thrust on my DX6i without mixing any channels I used a v-tail mixer. You can see where it is plugged in at rudder and throttle.
Heres the differential thrust in action on my DX6i.
When I maidend my build I felt the whole setup was way under powered and found myself using 3/4 to full throttle most of the time. The only cw and ccw props I could find close to what I was looking for as a set in stock at HK (USA) were 8x4's. With these motors (Suppo 2208/14) I have found that 7x5's seem to work the best so I went home and threw the concept of counter-rotating props out the window and put on a pair of 7x5's. I was worried about unwanted torque roll with two motors spinning the same direction but couldn't wait for my next chance to go flying again so I could try it out. Today was the day. I'm happy to announce, no torque issues at all, I don't think I even changed my trim from the maiden, and the differential thrust does work! My wing isn't going to be doing any knife edges anytime soon but I was able to navigate using only elevator and differential thrust and was able to do so quite well. I've never flown a plane with rudder and ailerons (I like planes that bank and yank) so I'm not really sure what all can be done with a rudder but I was able to get my wing into a verticle stall then decide if I wanted it to fall left or right using differential thrust. I can also get it to yaw a little if I give it some differential thrust in one direction and push the ailerons (elevons) in the opposite direction. But I don't know if thats the proper way to get a plane to do a flat yaw and I've had no practice doing it. I honestly expected to be able to get it to yaw more but I don't know if the problem is with the differential thrust or my inexperience.
When I fly a plane I like to be able to cruise at below half throttle. The issue I had with the 8x4 props caused me to pack a couple Suppo 2212/10's in my backpack just in case changing the props didn't help enough. I liked the difference the 7x5's made on the 2208/14's and I was at a good cruising speed right around half throttle but I brought the 2212/10's so I had to try them. I have to say, they worked very well and I enjoyed using them very much. With those motors verticle wasn't unlimited, but it took a long time for the Wing to stall. They would be my perminate motors to use on this Wing however, using the same size (3s 2200) batteries my flight time seemed to be pretty much cut in half. I want to use this plane for fpv so reduced flight time to me is a bummer.
Lastly, my camera man was unavailable today but I will get some video of the stalls and yaw I can produce with differential thrust soon. If anyone can think of anything else they want me to try using the differential thrust please let me know and I will do my best. And no, it won't do flat spins, at least I haven't been able to get it to do any, but I don't really know how to get it to spin other than just holding the rudder full over and that hasn't worked.
When I watched the "Let's Fly" video for the Blunt Nose Versa I noticed this HUGE gap between the control surfaces and I instantly knew I had to do something about that so I went in the shop and got to work.
While building this thing I remembered a video where a guy (MyGeekShow) tried to use thrust vectoring to act as a kind of "rudder" on a delta wing and my mind went to differential thrust. I didn't have all the details worked out for differential thrust by the end of the build but I went and maidend my creation anyway without it. It flew really nice and was very stable from the beginning. A little trimming was all it took and it was good to go.
After the maiden, and a few additional successful flights that day, I came home with the idea of using differential thrust on my DX6i still nagging in the back of my mind. So I hopped online and did some digging and came across an article (and I really wish I could find it again so I could give the guy credit) where someone suggested using a v-tail mixer since the DX6i has some kind of issue with binding differential thrust to the rudder channel. So I ran out to the shop and threw it together using a v-tail mixer.
I have added some pictures of my work and a video at the bottom demonstrating the differential thrust. Please comment and let me know what you think. Also, I'm very new to the RC hobby so any suggestions would be great!
I put the esc's as far forward as I could get them to help balance out the weight of having two motors in the back.
I'm pushing the Blunt Nose Versa with a pair of Suppo 2208/14 1450kv motors swinging 7x4 props. (Not the cw and ccw 8x4's shown in this picture)
I used magnets to hold the hatches shut and nylon control horns for handles.
I'm running everything on two 3s 2200's in parallel with that adapter and wire mess.
To get differential thrust on my DX6i without mixing any channels I used a v-tail mixer. You can see where it is plugged in at rudder and throttle.
When I maidend my build I felt the whole setup was way under powered and found myself using 3/4 to full throttle most of the time. The only cw and ccw props I could find close to what I was looking for as a set in stock at HK (USA) were 8x4's. With these motors (Suppo 2208/14) I have found that 7x5's seem to work the best so I went home and threw the concept of counter-rotating props out the window and put on a pair of 7x5's. I was worried about unwanted torque roll with two motors spinning the same direction but couldn't wait for my next chance to go flying again so I could try it out. Today was the day. I'm happy to announce, no torque issues at all, I don't think I even changed my trim from the maiden, and the differential thrust does work! My wing isn't going to be doing any knife edges anytime soon but I was able to navigate using only elevator and differential thrust and was able to do so quite well. I've never flown a plane with rudder and ailerons (I like planes that bank and yank) so I'm not really sure what all can be done with a rudder but I was able to get my wing into a verticle stall then decide if I wanted it to fall left or right using differential thrust. I can also get it to yaw a little if I give it some differential thrust in one direction and push the ailerons (elevons) in the opposite direction. But I don't know if thats the proper way to get a plane to do a flat yaw and I've had no practice doing it. I honestly expected to be able to get it to yaw more but I don't know if the problem is with the differential thrust or my inexperience.
When I fly a plane I like to be able to cruise at below half throttle. The issue I had with the 8x4 props caused me to pack a couple Suppo 2212/10's in my backpack just in case changing the props didn't help enough. I liked the difference the 7x5's made on the 2208/14's and I was at a good cruising speed right around half throttle but I brought the 2212/10's so I had to try them. I have to say, they worked very well and I enjoyed using them very much. With those motors verticle wasn't unlimited, but it took a long time for the Wing to stall. They would be my perminate motors to use on this Wing however, using the same size (3s 2200) batteries my flight time seemed to be pretty much cut in half. I want to use this plane for fpv so reduced flight time to me is a bummer.
Lastly, my camera man was unavailable today but I will get some video of the stalls and yaw I can produce with differential thrust soon. If anyone can think of anything else they want me to try using the differential thrust please let me know and I will do my best. And no, it won't do flat spins, at least I haven't been able to get it to do any, but I don't really know how to get it to spin other than just holding the rudder full over and that hasn't worked.
