| Good comments Bobby. RFI (radio frequency interference) is an age old problem with electronics when working with nearby radio transmitters.
The EC2/3 fix that has worked in all the cases where relocating cables, antennas etc. was not successful has been to install a .1 uf capacitor from the map sensor output to ground. I’m at my off grid shack in CO so don’t have all my files with the details of that fix but it’s probably in the archives here somewhere.
I’m still repairing my RV-8 that stays here in CO. Here are the gory details. I had an incident on takeoff a few weeks ago. Just as I was approaching rotation speed a strong crosswind gust that overpowered full rudder forced me off the left side of the runway. Did I mention it was a STRONG gust? The ground was reasonably smooth so I elected to continue the takeoff as the safer option since I was within a second or two from liftoff.
That plan went fine until I hit the edge of an intersecting taxiway. There was about a 4 to 5 inch drop off at the edge and when my left gear hit this obstacle at ~60 mph the following events happened in rapid succession. The left wheel pant impacting the taxiway edge caused all the attach points to break away and it began to rotate underneath the wheel. As it did, the sharp point at the rear impacted the underside of the wing puncturing the skin 1 inch behind the wing tank. (This was the single bit of good fortune that day 😏) The hole was big enough to drain the tank very quickly had it been a couple of inches further forward. BTW, This was the left side tank that always feeds the engine on my setup.
I’m guessing the combined effect of hitting the edge of the taxiway and running over the wheel-pant was like hitting an obstacle about 8 inches tall. It was too much vertical load for the structure to bear so the side of the fuselage above the gear leg buckled up and folded like an accordion. Since this is the area of the fuselage where the forward attach point of the fuel tank is, it ripped the inboard rib of the fuel tank while folding up causing fuel to start pouring out.
Since at this point I was right at minimum liftoff speed, the vertical energy of the impact launched me into the air. Time to fly the airplane. Not enough room to land straight ahead, the airplane feels 'funny' but controllable so I turn downwind for a close in pattern. It was at this point I noticed the fuel spraying into the cockpit down where the fuel line enters the fuselage. The fumes are so strong that I worry about passing out or fire and think about jettisoning the canopy but the fuel spray stops before I get serious about that. The plane is behaving oddly, the main thing being the airspeed is way lower than it should be. I began the takeoff with no flaps but then I notice that they are now at full flaps, the throttle quadrant and flap control switch are mounted just above the left gear so the switch must have been forced on during the impact. The linkage to the switch is intact so I take off all the flaps and the airspeed starts coming up.
I know I must have a damaged gear but not how badly or even if the gear leg and wheel are still attached. I radio Unicom requesting a visual check of my gear but no one is on. I worry momentarily about there being enough fuel left in the tank to complete the pattern, state of the landing gear, etc but make the conscious effort to stop worrying about anything other than controlling the plane at the moment. That’s the best advice I can give anyone in a situation like this.
The rest of the pattern went 'normally', the only difference being the decision on whether to land on or to the side of the paved runway. Not sure it was the right choice in retrospect but I chose the pavement. Did a full flap soft field landing approach and the relief of feeling rubber instead aluminum touching down was amazing. The gear was far too distorted to maintain normal control but I came to a stop off the left side of runway and right side up.
There were the usual airport bums who gave me all the help needed to get the plane back in the hangar. They took a look at it and said something like “That is some bad landing damage!”. They had a hard time believing it happened on takeoff and made it around the pattern like that. #MeToo! 😱
Matt Dralle who runs one of the RV forum sites did have a landing incident that resulted in exactly the same damage on his RV-8. I checked to see what he decided about repairing and he determined he would not try repairing so ended up replacing the entire fuselage. I’m going to repair instead. Won’t be easy but I’m sure it’s doable. I’ve almost completed the removal of damaged stuff, I’ll order the parts and put back together when I return next spring.
Tracy Crook Andrew,
I originally had an SL-30 and keying the mike would cause the engine to stumble. Mark Steitle’s SL-30 would cause erratic capacitance fuel level readings (EFIS) when transmitting. Sam H. had engine stumble but I’m not sure what radio. My 430w causes a small change in the sound of the engine on the ground but not noticeable in flight. SL-30 has a service bulletin that helps with this problem. Using double shielded coax, keeping the coax away from EC wiring should help. Sam tested different antenna locations more to the rear of the aircraft.
Bobby
Sent from my iPad Update: ended up splitting coil power into 2 circuits, leading/trailing, with independent feeds/fuses/switches, now can check ignition on A & B ECU rather than just B as per EC2 wiring. Also cleaned up a bit more wiring as I had inadvertently created a ground loop on my radio to efis serial cable by connecting the shield to ground at both ends by mistake. Radio works better but now an old problem has returned that I thought I had fixed as Tracy had years ago, given instructions on installing some part to the circuit board, when I transmit on radio the engine misses, think the injectors are going full open and flooding engine again. seems to only happen in flight which has got me buggered as the engine cannot know its flying.
Going to try rewiring components back to the battery. as now I think it could be something to do with the battery being moved for CoG and components losing their independent feeds & ground back to the battery.
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