Jesse
Well Known Member
Well, I think it's about time that I post a few of my experiences with the EFII system (dual ignition and injection) in the RV-10. I do believe N930M is the first RV-10, and possibly the first 6-cylinder engine, to be flying with the full EFII system. I now have 20 hours in it and feel like I should share my experiences and thoughts on it. I have talked to several people who have shown interest or who are planning to install it in their -10's, so this is mainly for those people, or those who may be on the fence.
First of all, it is a system that required, IMHO, a fair bit more planning than a standard engine with mags and mechanical fuel injection. Even with electronic ignition on one or both sides. I have had a few misgivings of flying -10's with dual lightspeeds, but that didn't last very long. I am actually very much looking forward to flying with the P-mag if/when they ever actually start delivering them. With dual electronic ignition and electronic injection, though, it mecomes much more serious. You really should have dual batteries, at at least dual contactors, if not full dual busses. You really should have dual alternators, or at least it's a very good idea. You need dual fuel pumps because there is no engine-driven pump. if any of these systems aren't redundant and the only one fails, you either are immediately a glider or shortly will be. I know that the battery can keep you going for a while if the alternator fails, but I'm not about to test how long that is. I also think it's very important to have dual ECU's, one controlling each ignition and each can separately control the injection system. I know this becomes a fairly expensive system, but just think, at least it's only 30-year-old technology instead of 80-year-old technology.
To be perfectly honest, it took several weeks after first engine run for me to get up the nerve to climb in and go flying. I was very careful to stay within gliding distance of the runway for the first several hours. I just didn't fully understand all that was going on (still don't) and was nervous about being the test pilot for a new system. I have done first flights before, but never with a system that had never flown in this configuration before (at least that I am aware of).
The setup was, honestly, a little disappointing. Rob has been fairly available, usually with a call back after leaving a voicemail. I know this system has run on a test stand on more than one occasion, and honestly there were a TON of settings that I had to put in from a spreadsheet that should have been put in at the factory. It was not a mystery that this was going in a -10, so the 300 pages of settings should have been preset. After getting them going and doing the ground testing to setup more accurate fuel mapping, I got to the point where I was willing to take to the skies.
Most of the above has been fairly negative, but I think a lot of it is plowing new ground and the time we have spent on this one should help others down the road. I now have 19.8 hours on the system, and it has not missed a single beat in flight. There have been some issues in starting and things like that, but we are figuring out what works. I have not taken the time to tweak all of the fuel maps and settings, but we have things mostly setup and I have been very impressed with the way it has operated so far. Up until the last few hours, I have still told people, "the jury is still out," but I am getting much closer to a verdict now. It took this long for me to get to the point of saying, "I would climb in and fly it to the Bahamas," or "I would feel comfortable putting my kids in it and flying to Kansas."
Some things different about the system and the way the engine runs are the following:
1. I can run this engine as low as 400 rpm and it is smooth. I have never run an IO-540 lower than 750-850 rpm because it shakes and shudders. It must be a combination of the variable timing and the fact that the fuel is electronically injected into the intakes for each cylinder, so at low rpm all cylinders are still getting the right amount of fuel.
2. I have done some extensive leaning in flight and have yet to get to the point where the engine stumbles or starts to miss. This is probably related to the same as #1, but it can run amazingly lean in flight and still run smooth. Yes, at a point you start loosing enough power that you give up a lot of speed, but I truly don't think I have seen fuel flows as low in a standard -540 as I have seen in this one, at the same MAP and RPM settings.
3. There truly is no such thing as a hot start issue. I know, you can tell me until you are blue in the face that you have a perfect system that works every time and you never have a problem with hot starts. I have flown probably 20 different RV-10's and many more than that different fuel injected engines, and the hot start is more difficult than a cold start. I have a system that works most of the time, but I have yet to see a system that consistently requires no more cranking than a cold start. The EFII starts hot exactly the same as it starts cold, if not a little better. Since so much fuel is being pumped back to the tank, any time your master is on you have cool fuel in the system.
4. While you can use the mixture knob (potentiometer mounted on the panel) to adjust your AFR (Air Fuel Ratio), there is truly much less mixture adjustment as altitude changes as long as power setting doesn't. I know I have said recently, "if you think you won't be touching the mixture control, you are mistaken," or something along those lines. However, as you get things setup more, once you get setup in cruise with your MAP, RPM and AFR where you want them, you really can fly the rest of your flight that way...INCLUDING THE DESCENT. This is something that really stands out to me. Let's say I am flying along at 12,500 feet at 18" MAP, 2,300 RPM and AFR of 16.7. I can descend to pattern altitude with nothing to touch except the throttle knob. The governor keeps the prop at 2,300 RPM and the EFII keeps the AFR at 16.7 (more or less, but close). With a standard injection system, I have to keep adding mixture the whole way down. I usually find myself going to the rich side of peak as I descend simply so I don't have to adjust the mixture as often. When I see the EGT's start to climb towards peak, I richen up a bit more. If I don't do this and I don't stay on it, I end up getting so lean that the plane really accelerates when I add mixture. With the EFII, you really don't have to touch anything until you are on final, when you are preparing the mixture knob and the prop control for a go-around if you need one.
Final thoughts:
1. Would I recommend the EFII system to other people building RV-10's? That depends. Some people just want to fly. They want to climb in and go somewhere and not have to think about it. For them I would say, go with mags and a Bendix, Silverhawk or AFP injection system and enjoy. For those who want to do the tweaking and testing to get a little better performance or better economy, then this just might be the system for you.
2. Doesn't useable fuel decrease because you are dumping so much fuel back in the tank and could start sucking air at a higher fuel level? I burned a tank down until I saw 0 on the Dynon and it took 29.5 gallons to fill back up. I didn't wait until it missed, but it was running solid up to that point. I doubt there is more than a quart of difference in useable fuel, if that much.
3. Would I put my wife and/or children in it? I have already answered this, but the true answer is, "not all of them at the same time."
There are too many of them. Yes, I would put my loved ones in it.
4. Does it truly perform better than a standard system? Honestly, I don't know, but it sure seems to. Without quoting a lot of numbers, I think it does perform a little better, and I have not gotten very deep at all into the tweaking to make it even better yet.
First of all, it is a system that required, IMHO, a fair bit more planning than a standard engine with mags and mechanical fuel injection. Even with electronic ignition on one or both sides. I have had a few misgivings of flying -10's with dual lightspeeds, but that didn't last very long. I am actually very much looking forward to flying with the P-mag if/when they ever actually start delivering them. With dual electronic ignition and electronic injection, though, it mecomes much more serious. You really should have dual batteries, at at least dual contactors, if not full dual busses. You really should have dual alternators, or at least it's a very good idea. You need dual fuel pumps because there is no engine-driven pump. if any of these systems aren't redundant and the only one fails, you either are immediately a glider or shortly will be. I know that the battery can keep you going for a while if the alternator fails, but I'm not about to test how long that is. I also think it's very important to have dual ECU's, one controlling each ignition and each can separately control the injection system. I know this becomes a fairly expensive system, but just think, at least it's only 30-year-old technology instead of 80-year-old technology.
To be perfectly honest, it took several weeks after first engine run for me to get up the nerve to climb in and go flying. I was very careful to stay within gliding distance of the runway for the first several hours. I just didn't fully understand all that was going on (still don't) and was nervous about being the test pilot for a new system. I have done first flights before, but never with a system that had never flown in this configuration before (at least that I am aware of).
The setup was, honestly, a little disappointing. Rob has been fairly available, usually with a call back after leaving a voicemail. I know this system has run on a test stand on more than one occasion, and honestly there were a TON of settings that I had to put in from a spreadsheet that should have been put in at the factory. It was not a mystery that this was going in a -10, so the 300 pages of settings should have been preset. After getting them going and doing the ground testing to setup more accurate fuel mapping, I got to the point where I was willing to take to the skies.
Most of the above has been fairly negative, but I think a lot of it is plowing new ground and the time we have spent on this one should help others down the road. I now have 19.8 hours on the system, and it has not missed a single beat in flight. There have been some issues in starting and things like that, but we are figuring out what works. I have not taken the time to tweak all of the fuel maps and settings, but we have things mostly setup and I have been very impressed with the way it has operated so far. Up until the last few hours, I have still told people, "the jury is still out," but I am getting much closer to a verdict now. It took this long for me to get to the point of saying, "I would climb in and fly it to the Bahamas," or "I would feel comfortable putting my kids in it and flying to Kansas."
Some things different about the system and the way the engine runs are the following:
1. I can run this engine as low as 400 rpm and it is smooth. I have never run an IO-540 lower than 750-850 rpm because it shakes and shudders. It must be a combination of the variable timing and the fact that the fuel is electronically injected into the intakes for each cylinder, so at low rpm all cylinders are still getting the right amount of fuel.
2. I have done some extensive leaning in flight and have yet to get to the point where the engine stumbles or starts to miss. This is probably related to the same as #1, but it can run amazingly lean in flight and still run smooth. Yes, at a point you start loosing enough power that you give up a lot of speed, but I truly don't think I have seen fuel flows as low in a standard -540 as I have seen in this one, at the same MAP and RPM settings.
3. There truly is no such thing as a hot start issue. I know, you can tell me until you are blue in the face that you have a perfect system that works every time and you never have a problem with hot starts. I have flown probably 20 different RV-10's and many more than that different fuel injected engines, and the hot start is more difficult than a cold start. I have a system that works most of the time, but I have yet to see a system that consistently requires no more cranking than a cold start. The EFII starts hot exactly the same as it starts cold, if not a little better. Since so much fuel is being pumped back to the tank, any time your master is on you have cool fuel in the system.
4. While you can use the mixture knob (potentiometer mounted on the panel) to adjust your AFR (Air Fuel Ratio), there is truly much less mixture adjustment as altitude changes as long as power setting doesn't. I know I have said recently, "if you think you won't be touching the mixture control, you are mistaken," or something along those lines. However, as you get things setup more, once you get setup in cruise with your MAP, RPM and AFR where you want them, you really can fly the rest of your flight that way...INCLUDING THE DESCENT. This is something that really stands out to me. Let's say I am flying along at 12,500 feet at 18" MAP, 2,300 RPM and AFR of 16.7. I can descend to pattern altitude with nothing to touch except the throttle knob. The governor keeps the prop at 2,300 RPM and the EFII keeps the AFR at 16.7 (more or less, but close). With a standard injection system, I have to keep adding mixture the whole way down. I usually find myself going to the rich side of peak as I descend simply so I don't have to adjust the mixture as often. When I see the EGT's start to climb towards peak, I richen up a bit more. If I don't do this and I don't stay on it, I end up getting so lean that the plane really accelerates when I add mixture. With the EFII, you really don't have to touch anything until you are on final, when you are preparing the mixture knob and the prop control for a go-around if you need one.
Final thoughts:
1. Would I recommend the EFII system to other people building RV-10's? That depends. Some people just want to fly. They want to climb in and go somewhere and not have to think about it. For them I would say, go with mags and a Bendix, Silverhawk or AFP injection system and enjoy. For those who want to do the tweaking and testing to get a little better performance or better economy, then this just might be the system for you.
2. Doesn't useable fuel decrease because you are dumping so much fuel back in the tank and could start sucking air at a higher fuel level? I burned a tank down until I saw 0 on the Dynon and it took 29.5 gallons to fill back up. I didn't wait until it missed, but it was running solid up to that point. I doubt there is more than a quart of difference in useable fuel, if that much.
3. Would I put my wife and/or children in it? I have already answered this, but the true answer is, "not all of them at the same time."
There are too many of them. Yes, I would put my loved ones in it.4. Does it truly perform better than a standard system? Honestly, I don't know, but it sure seems to. Without quoting a lot of numbers, I think it does perform a little better, and I have not gotten very deep at all into the tweaking to make it even better yet.
