_Rade

I'm having the same problem. I've uploaded the craft file but it doesn't let me publish it.

@panzer1b What is the location of your base? I'm asking because it's really hard to find such flat terrain on Duna. Also from my tests I've found out that breaking ground propellers don't seem to work that well on Duna. I couldn't get the plane to go faster than 100m/s and that was at low altitudes usually below 1000m, at about 3000m plane couldn't even move fast enough to takeoff from the ground.

Structural fuselage to act the same way as the cargo bays (drag occlusion) for the small objects placed inside the fuselage. It's really annoying having to use fairings on airplanes in order to be able to shield parts like fuel cells from the aeroforces in flight.

I've updated couple of my older planes by replacing the reaction wheel engines with the new rotors and propellers. Performance provided by these new parts is amazing. While using just 2 smallest rotors to run 3 bladed contra-rotating propellers I was able to get the planes to go ~250 m/s at low altitude. Link to the craft files: VB 10 Air Racer

I'll try those panels, only problem is they are wider than the decouplers so they might not work so well.

@sgt_flyer That thing looks amazing, real shame about the in game performance. Did you try to replace every second hinge with some other part, it wont reduce the part count but it would cut the number of hinges in half and that might help. Anyways here's my new tracked rover Only 20 hinges for each thread in order to keep impact of the hinges on the performance to the minimum. Also I've redesigned the sprocket wheels, now they are similar to the sprockets on the t-34. This have considerably improved how the threads interact with the sprocket wheels. The max speed increased to ~7 m/s and it's now mostly limited by the impact tolerance of the decouplers I used for the track links. Here's the link to the craft file https://kerbalx.com/Rade/Crawler and a link to the video on Reddit

Here is my take on the tracked propulsion. By using the decouplers to make the track links I was able to cut down the number of hinges by more than a half, each track is 38 hinges and decouplers. Hinges are in the middle of the track and along with the double wheels they serve as guide for the track. Front idler wheels are mounted on a pistons which can be used to adjust the tension of the track. Whole thing works reasonably well as long don't apply to much torque to the engines, max. speed is about 5 m/s. Main problem I've had with it is that all these hinges really slow down the game. The other problem are the KSP's stretchy joints, which make it really hard to properly tension the tracks, this can cause the track to either stretch or skip on the sprocket wheel and in turn this can de-track or break the tracks. Here is the link to the craft file https://kerbalx.com/Rade/Tank and a link to the Reddit post where I have posted a video of this thing in action

My new helicopter, it's not a turboprop but it does have coaxial rotors with the working swashplate and collective, also yaw is controlled via the rotor engine rpm. Craft file H-21 Frelon

Using the new parts I've made a working drive shaft that uses universal (Cardan) joints. Best part is this thing works surprisingly well, and if you wanted you could have drive shaft that makes 90 degrees turn. Only downside is there is a power loss for every joint you add. Craft file https://kerbalx.com/Rade/Kardan

You could just attach a cubic strut to the rotor and then put 4 more cubic struts around it to hold it.

Nice to see it works, I'm glad I could help. Also if you're using 1.25m parts you might as well go for the fairing/stayputnik combo for the bearing. It's probably the one of the best bearings for the propellers, mainly because it's really strong and fairing occludes the engine parts from the drag, which makes the planes that use these propellers much faster.

@Phantomic try using some other parts that have higher thickness than thermometers, the 5-way rcs and gravioli might work. Also it might help to include short I-beam as the root part of the rotor and then attach and autostrut all parts of the rotor to the I-beam, this should make the rotor more rigid and less likely to break.

I finally did it, I made the helicopter with a working swashplate. I've used more or less the same design I've posted few days ago. First I've tried using only the rotor with the swashplate, but it can only spin about 16-17rad/s before breaking up. That's not fast enough to provide sufficient lift for the helicopter. So I've added additional coaxial rotor that just provides the lift, while the rotor with the swashplate is used to control the helicopter and provide a little bit of lift. Also the tail rotor can slide left or right via the elevon that's controlling its position. In neutral position rotor is spun just by 2 juno engines. If you want to turn right rotor is positioned so that 4 junos act on it to spin it faster. If you want to turn left rotor is positioned out of the way of juno engines, so it idles and slows down and the torque from the main engines turns the helicopter. Craft file.

Thanks for the info on that, I've never had this issue before. I've used the cubic octagonal struts as the root part for the rotor blades. I'm gonna rebuild the blades to see if this contraption will work at higher RPM.

I've finally managed to build the helicopter rotor with the working swashplate and collective. Rotor uses 2 decouplers to act as the swashplate, and then there is one rcs ball for each rotor blade captured between the decouplers. 4 elevons bellow the swashplate control its pitch and roll and this is then transferred to the rotor blades. For the collective I've used 2 elevons to push up on the rcs ball that act as the bearing for the swashplate. You can toggle these by engaging the brakes, it's not perfect but it works. Only problem is the rotor will only spin at about 7rad/s. I've tried adding more engines and using the reaction wheels but for some reason it doesn't want to spin faster. One thing that is interesting is that if you don't decouple the rotor blades the rotor will be able to spin faster, but then the swashplate and collective don't work. Link to the craft file on KerbalX.

Thing about the probe core vs. manned, is that the plane with a small okto probe inside the fairing will be about 1t lighter and it will also have less drag compared to the plane which would have to use the cockpit. for example this thing can go 218m/s at low altitude, but if you where to remove the cockpit and just control it via the probe core maximum speed increases to 228m/s.

Yea that's his forum name here. It was updated, works great. Is that 20 small wheels per plane or per engine? For additional rules I would recommend to make the cockpit a required part, otherwise the drones would have unfair advantage over manned planes. There should be some rule or maybe 2 separate classes for the different propeller blade configurations. for example plane with this prop blade config (ignore the rotors) will have a considerable speed advantage over a same plane with prop blades arranged like this: Also maybe there should be some rule to limit the maximum diameter of the propeller, because bigger props will have a speed advantage provided you have enough reaction wheels to spin the prop at full speed.

@Phantomic I usually use the stayputnik/1.25m fairing combination, mainly because it is almost unbreakable and because the fairing occludes the engine parts. The other combination is linear RCS/solar panels bearings, these seem to work slightly better than thermometers, while being only slightly bigger. But these bearings can break if you do some sharp maneuvers or if the propeller is spinning to fast. Regarding the spacing of the parts I would recommend you to get the Collide-o-Scope mod. This will allow you to see the exact collider shape for any part, which allows you to precisely position the parts of the bearing. I might be interested in the race, but I would need to know if there are any rules, like the number of engines or reaction wheels allowed. As you've probably seen few people have managed to build prop planes that can go faster than Mach 1, with the @Tyr Anasazi holding a speed record with a Mach 2 capable plane. Also you might want to invite @SuperHappySquid into the race he is one of the best when it comes to building the stock propellers.

Try to minimize the drag and mass of the plane as much as possible, that should help with the increasing speed. Also it should be safe to increase the rotation speed to 2850deg/sec. The plane I'm using is just a version of my VB 10 propeller plane with stock propeller engines removed and replaced with step motors.

Here's how I have it set up. The front motor is attached to the battery, the rear one is attached to the NCS adapter. Also both motors are on the same action group so they start to spin at the same time when you activate them.

You're probably right about that, for a stationary plane each propeller blade provides about 10kN of lift and also little more than 10kN of drag which is converted to torque on the plane. So if you have a 3 bladed propeller it's like having a large reaction wheel trying to spin the plane in opposite direction. However as the plane accelerates the lift from the blades increases while the drag drops close to the 0.

Really nice and useful mod. I've tried using the BF-35 Size 0 Step Motor to build propeller powered airplane, and while it worked there where few issues with the motors. First issue is that the maximum rotation speed supported by the game is 50rad/s, while this part allows you to set the rotation speed to 3600deg/s which is ~62.83rad/s. From my experience in building the stock propeller engines I know that any time you have parts spinning faster than 49.8rad/s and close to 50rad/s you'll have various issues. Usually parts will wobble around or just break down. I would suggest to reduce the maximum rotation speed to at least 2850deg/s (49.74rad/s) or maybe even to 2835deg/s (49.48rad/s) just to be on the safe side. Second issue is that these engines give out allot torque for some reason. This makes it really hard to build airplanes with a single engine. I was able to overcome this problem by using 2 of these engines and the contra-rotating propellers. My test airplane Had to reduce the max speed to 2850deg/s otherwise the parts attached to the step motors would wobble around and then break down. I was able to reach max. speed of 230m/s using these engines. Similar plane using the stock propellers can go about 215m/s.

There is no need to rebuild the whole thing, just once you're done with building the rocket edit the fairings on the engines and that should fix any issues. Of course make sure you test the engines before sending the plane to Duna.

The first plane was built way back in 1.2.2. and I haven't really tested it with the newer versions of the game. The 1.4 introduced quite a few changes with the way the fairings work and that is maybe causing some issues with the engines. As for the second plane it is a known bug with the fairings. Most likely what happened is that while you where building the rocket you used Ctrl+Z to undo something and this causes the fairing bug to appear. Easy way to fix this is to simply edit the fairings on each engine and just close back the last section of the fairing. Doing this should fix any issues with the fairings.

Nice effort. I'm surprised you where actually able to land it with those elevons deployed like that. It looks like the symmetry bug may have switched the symmetry from mirror to radial on some of the elevons. It most likely happened when you attached the plane to the carrier rocket.