November 4, 2013 at 2:31 pm #84563
I’ve always thought that dynamically balancing props was a good idea, but I’d never done it before. It mainly came down to not liking to take my plane to unknown shops and not having a known shop that did it. Then with the new engines on the 310 I wanted to wait until 50 hours or so because of the ground run aspect with fresh cylinders.
When my friends/coworkers who are also A&Ps and have a shop told me they were going to start offering this service, I decided now would be a great time to do it. They balance turbine engine components at their day job and are very conscientious and thorough, so I was confident I’d be happy with the results.
Starting off, the right engine was at 0.5 IPS. According to the book, anything below 0.2 is good. 0.1 or below is optimal. We got the right engine down to 0.1 total. The left engine started at 0.65. We got that down to 0.04, but then when we put the weights in their final position and did the final balance run it went back to 0.17. That was confusing for us, but it was getting dark (we showed up pretty late), so we decided that I’d fly back another day to trim it out a bit more.
Doing the ground runs, you can’t really tell the difference. You only get up to 2,000 RPM and the wind causes most of the vibrations. But as soon as I went to takeoff power to go home, the difference was obvious. It was so smooth and quiet it felt like takeoff in the Cheyenne did. I actually thought something was wrong at first!
Once we got up to cruise (1500 ft – short flight) and pulled back to 2300-2500 RPM, the smoothness was even more apparent. “Turbine smooth” for sure. I took my headset off and leaned back to ask my wife (sitting in back with the baby – the baby had the headset) if she noticed a difference. Now, she’s the helicopter pilot who typically laughs at me when I ask if she notices a weird vibration. She absolutely noticed a difference. That’s also when the other part hit me – it was much quieter. Normally, I couldn’t take my headset off and be comfortable. Now, it absolutely is comfortable, and my wife noticed a big difference between the flight out and the flight home. This was only 30 miles each way, so it was a pretty drastic improvement to notice that quickly.
If you haven’t gotten your props dynamically balanced before, I’d recommend it. If you’re in the area, I’d recommend giving my friends a call at Buckeye Aviation (http://www.buckeye-aviation.com). I would suggest that you arrive in the morning to do both engines, especially this time of year when daylight is limited. I don’t mind the extra trip since they’re nearby, which is part of why I showed up late knowing that might happen.
If it’s this good at 0.17 and 0.1, I’m wondering how it’ll be if we can get them even lower…November 4, 2013 at 2:43 pm #101409
Fully agree with Ted.
For anyone in/near Wisconsin, my good friend at http://www.cwa-fbo.com has been balancing props for years and I can attest to his great work. He’s also a TTCF member.November 4, 2013 at 5:13 pm #101412
+1: All my props dynamically balanced, reduces wear & tear & fatigue (of people & airframe!)November 5, 2013 at 3:55 am #101440ccochran1Participant
Guys thanks for the information, couple of questions can anyone recommend a shop in IL? How much should I budget for my 310?
ChrisNovember 5, 2013 at 12:19 pm #101449jwarringtonParticipant
Can you give me a ballpark cost ?November 5, 2013 at 1:19 pm #101451
It’ll vary from shop to shop. My friends are charging $250/engine. I didn’t shop around, but I’d suspect they did to get an idea of what’s competitive. They’re also running a special where they’re doing $99/engine if you schedule your annual/100-hour with them. However, they aren’t Twin Cessna specialists. So figure $500 for the plane if you’re doing just the prop balance.
In Illinois, I know that Byerly Aviation does it (KPIA). I was going to have them do it last year, but they pretty much told me they didn’t want to, so I figured that if that was the case I didn’t want them doing it. I used to fly on their 135 cert and I know they do good work (they did the radar install on the 310), but they are usually on the expensive side.
If you’re nearby and fly out here (SW Ohio), then I’ll try to come meet you in our 310. Always fun to meet other TTCFers.November 5, 2013 at 5:00 pm #101454
Thanks for the post Ted I appreciate the info. I also have a slight vibration with my 414a VII I’m working to get resolved but I want to looking at obvious items first then likely a prop balance.
jeffNovember 5, 2013 at 5:52 pm #101456
I think we’ve got the 310 pretty close to optimal now. When the engines were done I had Charlie balance the internals, and now with the props, it can’t get much better.
I was at first chasing an issue with the mounts coming unseated on the left front mount. I can’t help but wonder if the prop vibration didn’t have something to do with that. We replaced the new mount with an old (harder) mount and it worked, but makes me wonder if we couldn’t put a new mount back in and have it better still.
After my 35 hour week coming up I’ll report more.November 20, 2013 at 6:46 pm #101626
I just got back from flying 40 hours in 5 days.
The smoothness was definitely noticeable. Actually now what vibrations I do notice get me wondering what’s causing them. Probably the biggest difference was the less fatigue I felt. Although I was certainly tired at the end of each day, I didn’t feel nearly as tired as I would typically expect to be. The fatigue was more mental due to a couple of legs that required elevated attention. Yesterday I flew 10 hours, and still felt alert when I shot the night approach back home.
An added benefit for sure.
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