tom paul
Active Member
This is embarrassing and I probably should keep this to myself, but I am not going to.
The other day, after my plane had been sitting for 6 weeks, I noticed that the throttle control was sticking. I have a throttle quadrant with a prop control and mixture. When advancing the throttle, the cable housing was deflecting down a lot first before the inner cable was moving inside it. I addressed this in two ways: I used a plastic cable tie to affix the throttle cable to the stable prop control cable that is next to it, up close to the quadrant. I also sprayed some LPS-1 greaseless lubricant on and into the inner cables for all three controls, as they felt sticky and made little squeaking noises. I also noticed a squeak coming from the hinge of the levers, so I sprayed a little lube there.
It worked great. I flew an hour across NY state, and had a wonderful flight.
The next day (today) i went for another 30 minute flight to complete my trip home. As soon as I took off, I noticed that the throttle and prop levers were not staying in position at all. The lube had done more work sitting overnight, and the levers would not hold their position. The mixture would stay put by itself, thankfully. I leaned for cruise, set the throttle and prop to around 24 square, and committed to holding both levers for the duration of the short flight. If I let go, the prop would immediately advance to full fine pitch, and the throttle would drop to around 15 inches or less.
I was flying along fine, having found a sustainable hand position on the quadrant, occasionally reaching over to the radio with my left hand while I steadied the stick with my knees.
Then I noticed a slight vibration. It was very subtle, but also undeniable. Everything looked good on the instruments. I could see my ADSB receiver shaking in a way it never had. It was a bit of a turbulent day, so I convinced myself it was just rough air. Then it got worse, and the RPM started to drop. I scanned the instruments, and cycled the mags (one of them is a Lightspeed) with no effect. I was trying to deny that this was happening, but the vibration got really bad and the RPM dropped through 2000. I became worried about a structural failure if the vibration got much worse. I cycled the prop control and full fine seemed to smooth it out a bit, though I was aware that I would want it as coarse as possible to get the best glide if things got really bad. I was over tree covered hills at 3500'. I hit "direct to nearest airport" on my Garmin GPS and it was 6.5 miles away. At 3500, that was dicey as a glide because i had never been there and didn't know exactly how high the hills around the airport were. I wasn't developing any real power by then as my RPM had dropped to 1500 and the shaking was getting really bad. I set up for best glide, and decided my best target was the thruway right below me. It was moderately busy, but I didn't see an option, looking around. My mind was racing as I accepted the reality that this was happening to me.
I thought I had done the Aviate and the Navigate, so it was now time to communicate. I dialed in the Stewart International Airport tower and was about to tell them what was happening. I set radio freq with my right hand, as I no longer needed to hold the engine and prop controls. When I returned my hand to the quadrant and did a muscle-memory push up on all three levers. The engine immediately sprang to life and developed full power.
It was the mixture. For 20 minutes the mixture had stayed put, but then it had slowly crept down and I didn't see it because my hand was in the way, holding the throttle and the prop. This explains the rough engine that quickly deteriorated to what felt like fuel starvation, because it was that.
Holy ****. I climbed back to my on-course altitude and heading and sat stunned at what I had just been through. I had to accept the fact that I was about to emergency-land a perfectly good airplane because of ridiculously bad piloting. The thing i didn't know about my new plane (been flying it solo since July) was that the throttle quadrant had a tension adjust lever on the right side! I never saw that and no one told me about it. The levers held their position just fine until i lubricated them, so I never questioned it. I found it after I landed at my home base. A 20 degree twist of the tension adjustment and the levers would hold their positions again.
There are many constructive takeaways for me from this, and it has made me a better pilot, I hope.
I think this speaks to the potential perils of purchasing a one-of-a kind homebuilt, especially as the third owner. Though there are close to 2,000 RV7s flying, none are exactly the same. I bought it from the second owner, who bought it nine years ago from the builder. I test flew it with a friend of the seller, and didn't get more than an hour sitting in the hangar with the seller, so there are perhaps a lot of idiosyncrasies that are mine to discover.
This makes me want to hangar-fly more and crawl around inside my plane to learn more about everything in there.
Sorry for the long post. I hope it wasn't too boring.
The other day, after my plane had been sitting for 6 weeks, I noticed that the throttle control was sticking. I have a throttle quadrant with a prop control and mixture. When advancing the throttle, the cable housing was deflecting down a lot first before the inner cable was moving inside it. I addressed this in two ways: I used a plastic cable tie to affix the throttle cable to the stable prop control cable that is next to it, up close to the quadrant. I also sprayed some LPS-1 greaseless lubricant on and into the inner cables for all three controls, as they felt sticky and made little squeaking noises. I also noticed a squeak coming from the hinge of the levers, so I sprayed a little lube there.
It worked great. I flew an hour across NY state, and had a wonderful flight.
The next day (today) i went for another 30 minute flight to complete my trip home. As soon as I took off, I noticed that the throttle and prop levers were not staying in position at all. The lube had done more work sitting overnight, and the levers would not hold their position. The mixture would stay put by itself, thankfully. I leaned for cruise, set the throttle and prop to around 24 square, and committed to holding both levers for the duration of the short flight. If I let go, the prop would immediately advance to full fine pitch, and the throttle would drop to around 15 inches or less.
I was flying along fine, having found a sustainable hand position on the quadrant, occasionally reaching over to the radio with my left hand while I steadied the stick with my knees.
Then I noticed a slight vibration. It was very subtle, but also undeniable. Everything looked good on the instruments. I could see my ADSB receiver shaking in a way it never had. It was a bit of a turbulent day, so I convinced myself it was just rough air. Then it got worse, and the RPM started to drop. I scanned the instruments, and cycled the mags (one of them is a Lightspeed) with no effect. I was trying to deny that this was happening, but the vibration got really bad and the RPM dropped through 2000. I became worried about a structural failure if the vibration got much worse. I cycled the prop control and full fine seemed to smooth it out a bit, though I was aware that I would want it as coarse as possible to get the best glide if things got really bad. I was over tree covered hills at 3500'. I hit "direct to nearest airport" on my Garmin GPS and it was 6.5 miles away. At 3500, that was dicey as a glide because i had never been there and didn't know exactly how high the hills around the airport were. I wasn't developing any real power by then as my RPM had dropped to 1500 and the shaking was getting really bad. I set up for best glide, and decided my best target was the thruway right below me. It was moderately busy, but I didn't see an option, looking around. My mind was racing as I accepted the reality that this was happening to me.
I thought I had done the Aviate and the Navigate, so it was now time to communicate. I dialed in the Stewart International Airport tower and was about to tell them what was happening. I set radio freq with my right hand, as I no longer needed to hold the engine and prop controls. When I returned my hand to the quadrant and did a muscle-memory push up on all three levers. The engine immediately sprang to life and developed full power.
It was the mixture. For 20 minutes the mixture had stayed put, but then it had slowly crept down and I didn't see it because my hand was in the way, holding the throttle and the prop. This explains the rough engine that quickly deteriorated to what felt like fuel starvation, because it was that.
Holy ****. I climbed back to my on-course altitude and heading and sat stunned at what I had just been through. I had to accept the fact that I was about to emergency-land a perfectly good airplane because of ridiculously bad piloting. The thing i didn't know about my new plane (been flying it solo since July) was that the throttle quadrant had a tension adjust lever on the right side! I never saw that and no one told me about it. The levers held their position just fine until i lubricated them, so I never questioned it. I found it after I landed at my home base. A 20 degree twist of the tension adjustment and the levers would hold their positions again.
There are many constructive takeaways for me from this, and it has made me a better pilot, I hope.
I think this speaks to the potential perils of purchasing a one-of-a kind homebuilt, especially as the third owner. Though there are close to 2,000 RV7s flying, none are exactly the same. I bought it from the second owner, who bought it nine years ago from the builder. I test flew it with a friend of the seller, and didn't get more than an hour sitting in the hangar with the seller, so there are perhaps a lot of idiosyncrasies that are mine to discover.
This makes me want to hangar-fly more and crawl around inside my plane to learn more about everything in there.
Sorry for the long post. I hope it wasn't too boring.