Ted
The pilot formerly known as Twin Engine Ted
- Joined
- Oct 9, 2007
- Messages
- 29,907
- Display Name
Display name:
iFlyNothing
I've been a fan of dynamic prop balancing since I'd first heard about it some years ago, but I never actually had gone out and done it before for various reasons. On the Aztec, my mechanics discouraged it because they figured that any prop shop would try to red tag the props (even though they were within limits per Hartzell, they had some dings) and I didn't know anyone who would do it. Then it was time for the Aztec to get gone, and I didn't see much of a point in doing it on the 310, knowing that it had the impending double engine overhaul. Then the engines were overhauled (with balanced rotating assemblies), and I wanted to put a good 50 hours on them at least before doing a dynamic prop balance, but I still wasn't sure who to have do the work. I only like to let people I trust touch the airplane, for obvious reasons.
As luck would have it, our own flyingmoose and VanDy of Buckeye Aviation (www.buckeye-aviation.com) decided to start offering dynamic prop balance services, so I jumped at the opportunity to get this work done on the 310.
The experience is pretty painless, but on a twin it obviously takes twice as long. We ended up splitting it up into two late afternoons because that's what fit my schedule. Although I would suggest allowing a full morning or afternoon per engine.
The summary is that the right engine started out at 0.5 IPS and got down to*0.1 IPS. The left engine started out at 0.65 IPS and we had down to an incredible 0.04 IPS, but then when the weights got permanently mounted ended up at 0.175 IPS (below 0.2 is considered "good", 0.1 or below is exclelent). We would have worked on it a bit more, but ran out of daylight (my fault for picking a late start time), so we'll plan on seeing if we can tweak it a bit further at a later point. In any event, the vibration levels are about 80% lower than they were.
I was somewhat wondering how noticeable the difference would be, having never done it before. When you're doing the vibration survey, you really can't tell the difference. You're only running the engine up to around 2000ish RPM, and the prop wash ends up shaking the plane around a bit. When I put the levers forward for takeoff power, I almost thought something was wrong. It was quiet and smooth like the turboprops I used to fly. Leveling off at cruise (a whopping 1500 ft for the 30 nm trip home), I pulled the power back to cruise and it felt turbine smooth, too. I pulled my headset off to ask Laurie (sitting in back without a headset) if she noticed a difference. With her helicopter time, when I ask her if she notices a vibration she usually laughs at me. She noticed a very significant reduction in both noise and vibration, and what struck me on the noise level was that I could actually comfortably fly without my headset on, which previously I couldn't do.
This weekend I've got a long trip that will have something around 30 hours of flight time (over 5 days or so), and I can't wait to fly with this improvement and see the reduction in fatigue due to less vibration and less noise.
If you haven't done this, I would strongly suggest doing it. I wish I'd gotten it done on the Aztec when I had it and on the 310 earlier. This is really some of the best money that I've spent on the airplane. It will be further interesting to see if, when we play with it a bit more to get the number down further, the difference will be noticeable at that point. But right now, the plane is absolutely "turbine smooth."
If you're not too far from the Cincinnati area, give Matt and Matt a call or check their website (www.buckeye-aviation.com) to schedule your prop balance. They're great to work with and are very professional, plus have great prices.
As luck would have it, our own flyingmoose and VanDy of Buckeye Aviation (www.buckeye-aviation.com) decided to start offering dynamic prop balance services, so I jumped at the opportunity to get this work done on the 310.
The experience is pretty painless, but on a twin it obviously takes twice as long. We ended up splitting it up into two late afternoons because that's what fit my schedule. Although I would suggest allowing a full morning or afternoon per engine.
The summary is that the right engine started out at 0.5 IPS and got down to*0.1 IPS. The left engine started out at 0.65 IPS and we had down to an incredible 0.04 IPS, but then when the weights got permanently mounted ended up at 0.175 IPS (below 0.2 is considered "good", 0.1 or below is exclelent). We would have worked on it a bit more, but ran out of daylight (my fault for picking a late start time), so we'll plan on seeing if we can tweak it a bit further at a later point. In any event, the vibration levels are about 80% lower than they were.
I was somewhat wondering how noticeable the difference would be, having never done it before. When you're doing the vibration survey, you really can't tell the difference. You're only running the engine up to around 2000ish RPM, and the prop wash ends up shaking the plane around a bit. When I put the levers forward for takeoff power, I almost thought something was wrong. It was quiet and smooth like the turboprops I used to fly. Leveling off at cruise (a whopping 1500 ft for the 30 nm trip home), I pulled the power back to cruise and it felt turbine smooth, too. I pulled my headset off to ask Laurie (sitting in back without a headset) if she noticed a difference. With her helicopter time, when I ask her if she notices a vibration she usually laughs at me. She noticed a very significant reduction in both noise and vibration, and what struck me on the noise level was that I could actually comfortably fly without my headset on, which previously I couldn't do.
This weekend I've got a long trip that will have something around 30 hours of flight time (over 5 days or so), and I can't wait to fly with this improvement and see the reduction in fatigue due to less vibration and less noise.
If you haven't done this, I would strongly suggest doing it. I wish I'd gotten it done on the Aztec when I had it and on the 310 earlier. This is really some of the best money that I've spent on the airplane. It will be further interesting to see if, when we play with it a bit more to get the number down further, the difference will be noticeable at that point. But right now, the plane is absolutely "turbine smooth."
If you're not too far from the Cincinnati area, give Matt and Matt a call or check their website (www.buckeye-aviation.com) to schedule your prop balance. They're great to work with and are very professional, plus have great prices.
