To alleviate this I put the switch on my sticks which to me is a bit of a no brainier. However I also wanted the flaps to work similar to planes that have 'notches' that work like a Showtime Rotisserie and you can "Set it and forget it!". Okay maybe not forget it, still need to make a visual check that the flaps are down but in reality you should feel it in the attitude of the plane. To accomplish this I choose to use a combination of a Ray Allen Position Sensor and the VPX.
I will note that PHAviation has taken an off the shelf actuator with a built in sensor which is a great idea. I'm sure it works great but the stock system I had already installed and the tunnel is a bit cramped with AC lines and the like. I didn't know how the larger actuator would affect that so the path of least resistance was a stand alone sensor.
Even mounting the sensor you have various options. My buddy Mike was able to install his in the tunnel similar to how the RV-14 is attached. That's probably a better way but again I had the tunnel all close up and didn't want to try and manage in that area with drills and what not. Others have mounted it on the tube itself using Adel clamps but to me that doesn't seem as solid of hard points. It's probably not likely but in theory a clamp could slip over time.
What I ultimately ended up doing was mounting it outside of the fuselage, directly connected to the flap horn itself. This is extremely easy to get to and solid enough that it's not going to slip around. There seems to be a concern of water getting in there but I mitigated that a bit with the bracket I made and the way it's positioned.
The bracket I made used a scrap piece of carbon fiber from some of my interior pieces. I had tried a few things with bending some metal into various shapes. I wasn't happy with any of those options then remember some of this scrap I had. It's light, strong and had the clearance where I was able to mount the sensor outboard enough to attach on the outside of the flap horn. I did want to strengthen it a bit so I used some adhesive and attached some skin aluminium to the mounting points.
Attaching everything together took a bit more work. Using RC Plane parts (Thanks Mike and Julie!) I worked a bit to determine the best location to place this thing. I found that if I mounted it off center on the horn then at the beginning of the horn movement it didn't register. The connecting rod would just rotate down. I also wasn't comfortable going between the root and first lighting hole. It may be fine, but as I'm not an engineer I don't know the kind of load this thing takes. Following another builders lead I decided to make a aluminium bracket and secure it onto the horn. I chose to put it inside the horn and stagger the rivets where there was more material. Took some time to shape it but then it was a matter of putting some adhesive onto the rivets and popping them in. I added some adhesive just to ensure these don't move over time.
The rest is just drilling holes, and attaching things together. I tried to get as close to a full 1.2 stroke of the position sensor as possible. I probably could of moved the rod up just a bit, but figured the middle of my aluminium piece had the most strength so that's where it went. Here is everything clecod for testing.
Placement of the bracket is fairly important. In short it perpendicular to the arm being at it's halfway point. The horn position in these pictures is with the flaps retracted or in the up position. Therefore I wanted the sensor to be all the way in. Then I rotated the bracket to that perpendicular angle did some testing with duct tape and the VPX and was happy with the movement and sensing which I'll talk about in a second. When I was happy with the position it was just match drilling and riveting.
Back to water protection. The only entry points into the sensor are on the bottom and where the actuator arm goes in and out. Placing it upside down protects the bottom from any moisture and having it slanted a bit should protect the arm. I suppose if you leave it on the ramp, with the flaps down in a heavy rain storm then water could get on the arm and then retracted into the unit.... I guess that's the chance I'm willing to take. Back up plan is manual extension of the flaps through the EFIS.
Talking about the EFIS and flap position I found the setup within the VPX extremely easy. You seem to be able to chose about 4 positions. Full up, and full down take up two of those positions. There's also a reflex option but I'm not sure what that does and haven't messed with it. The range of sensor movement for mine seems to be 0 - 227. So 0 is all the way up, so right now I have it stop at 1, then all the way down I have it stop at 226. I then just made the middle two increments of 75 for now. The way it works is I push down on the stick switch it goes one 'notch', down again the 2nd 'notch', 3rd time it's all the way down. Hit it once up and the flaps will fully retract. That's one thing I'm not a huge fan of, but there may be some way to change it. For now I selected the 'slow retract' option so if I'm on final and I inadvertently hit retract hopefully it gives me enough time to correct. Because I don't have the wings on as of yet I can't finalize any of these settings. My goal will most likely be 0, 10, 20, 30 degrees of flaps at each setting.
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.