X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 19 May 2011 16:45:31 -0400 Message-ID: X-Original-Return-Path: Received: from nm28-vm0.bullet.mail.sp2.yahoo.com ([98.139.91.234] verified) by logan.com (CommuniGate Pro SMTP 5.4c3j) with SMTP id 4988684 for lml@lancaironline.net; Thu, 19 May 2011 11:55:02 -0400 Received-SPF: none receiver=logan.com; client-ip=98.139.91.234; envelope-from=n20087@yahoo.com Received: from [98.139.91.61] by nm28.bullet.mail.sp2.yahoo.com with NNFMP; 19 May 2011 15:54:26 -0000 Received: from [98.139.91.29] by tm1.bullet.mail.sp2.yahoo.com with NNFMP; 19 May 2011 15:54:26 -0000 Received: from [127.0.0.1] by omp1029.mail.sp2.yahoo.com with NNFMP; 19 May 2011 15:54:26 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 601891.10689.bm@omp1029.mail.sp2.yahoo.com Received: (qmail 48430 invoked by uid 60001); 19 May 2011 15:54:26 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:MIME-Version:Content-Type; b=zFVX8WiUZSABIYjKxwI+zDc4xe4esGD7K2URKF34nyIAT+t/lA40Mi+BICt/1ZvgmU9pSfSGVvUKd9o+lRkwkSx5WQvypbulX9RlkF5gGoLClZWz63SpIvO8NoB1gLn8C/w3Ms5H/09yZHjVibYadKHyeaqdcRm1Tp8gtcZCeDo=; X-Original-Message-ID: <62969.32559.qm@web112719.mail.gq1.yahoo.com> X-YMail-OSG: aPs8FqsVM1nQQJhVNrlKIdfZw18uwARMecPYGy9WkYnVSjV fRMwpDAm5.wlrmP83JPVUM9wPaxf0DNRIAimFSvn9mjBYBaRjgl1.BrsjK8h yUfZoGKRJ5yd_tVt7PNRTUaAes41emO_cjR0i7wxUNs8sS8JolSbBMLXmty7 0KRT5Ax5tXB5VAZCgvmF5jYR.hunMHprV1jRQ5rUV4hnDwPuJzz4zyVc1xAm Ga2RhyAhOfSYC1adFKczRVoC2FRiR6rktw4Ux9fh1outgxaH8HoC3LRPZEpN 2Xtam1TkgN5V4pAo3BSr1AwyHbsrKccorQlF.8LnqfzjTGmmp4isJs2ZvEeX rMohSymJF9_ND4a4CuBq9RvriBLF1XCVkH8r._uMnTZQKATJVn4aKGnc- Received: from [192.88.212.68] by web112719.mail.gq1.yahoo.com via HTTP; Thu, 19 May 2011 08:54:25 PDT X-Mailer: YahooMailWebService/0.8.111.303096 X-Original-Date: Thu, 19 May 2011 08:54:25 -0700 (PDT) From: TOM GARDINER Subject: FW: LNC2 Vibration Issues X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="0-1569367839-1305820465=:32559" --0-1569367839-1305820465=:32559 Content-Type: text/plain; charset=us-ascii ----Forwarded Message---- From: n20087@yahoo.com To: n20087@yahoo.com Sent: Thu May 19th, 2011 11:26 AM EDT Subject: LNC2 Vibration Issues Folks I am dealing with a vexing problem which has plagued me throughout my phase 1 testing and that is, I can't get rid of vibration from my engine prop combination. I am running a Lycoming IO360/Slick Mags (non-counter weighted crank) with a new Hartzell HC-C2YK-1BF/F7666A. The prop was dynamically balanced on the ground at 23" map and 2400rpm to 0.05ips. Interesting thing is the vibration increases significantly to 0.25ips at 2500RPM on the ground. When flying, I can see the ASI needle vibrate a little (+/- 0.5mm) at high power settings >19Inches and any RPM. I have not been able to measure the vibration in the air since it is difficult to mount an accelerometer in the vertical plane under the cowl but I do see the stick vibrate a little from side to side when I let it go. Some additional background: 1. The engine has accumulated 44 hours since new 2. The crank was dynamically balanced at the factory 3. When the engine was built it was tested with a club and found to be vibration free 4. The prop has a 4" extension by Sabre Industries 5. The balancing weight was mounted to the flywheel in the form of an AN3 bolt/nut (20 grams) 6. The spinner is solidly fixed to the prop and back plate and is centered 7. The crossover exhaust and tailpipes are fixed to the engine only 8. The cylinders are 9:1 compression 9. All cylinder compressions are even and in the 70s 10. The engine mount bolts are torqued correctly to 40-45ftlb 11. The engine does not/cannot touch the cowl When I tested the aircraft at 17,500 feet, I noted the vibration was significantly less pronounced or non-existent due to the low power output. I noticed the same thing in cruise decent at 18 inches or lower. Talking to the prop balancing mechanic, he stated that it is unusual for balance to be ok at 2400 RPM but to be significantly different at 2500RPM+. I would be very grateful for any help and assistance from anybody with knowledge or experience in correcting vibration issues such as the one I described above Thanks Tom --0-1569367839-1305820465=:32559 Content-Type: text/html; charset=us-ascii

----Forwarded Message----

From: n20087@yahoo.com
To: n20087@yahoo.com
To: n20087@yahoo.com
Sent: Thu May 19th, 2011 11:26 AM EDT
Subject: LNC2 Vibration Issues

Folks

I am dealing with a vexing problem which has plagued me throughout my phase 1 testing and that is, I can’t get rid of vibration from my engine prop combination.  I am running a Lycoming IO360/Slick Mags (non-counter weighted crank) with a new Hartzell HC-C2YK-1BF/F7666A.

The prop was dynamically balanced on the ground at 23” map and 2400rpm to 0.05ips.  Interesting thing is the vibration increases significantly to 0.25ips at 2500RPM on the ground.  When flying, I can see the ASI needle vibrate a little (+/- 0.5mm) at high power settings >19Inches and any RPM.    I have not been able to measure the vibration in the air since it is difficult to mount an accelerometer in the vertical plane under the cowl but I do see the stick vibrate a little from side to side when I let it go.

Some additional background:

1.       The engine has accumulated 44 hours since new

2.       The crank was dynamically balanced at the factory

3.       When the engine was built it was tested with a club and found to be vibration free

4.       The prop has a 4” extension by Sabre Industries

5.       The balancing weight was mounted to the flywheel in the form of an AN3 bolt/nut (20 grams)

6.       The spinner is solidly fixed to the prop and back plate and is centered

7.       The crossover exhaust and tailpipes are fixed to the engine only

8.       The cylinders are 9:1 compression

9.       All cylinder compressions are even and in the 70s

10.   The engine mount bolts are torqued correctly to 40-45ftlb

11.   The engine does not/cannot touch the cowl

When I tested the aircraft at 17,500 feet, I noted the vibration was significantly less pronounced or non-existent due to the low power output.  I noticed the same thing in cruise decent at 18 inches or lower.  Talking to the prop balancing mechanic, he stated that it is unusual for balance to be ok at 2400 RPM but to be significantly different at 2500RPM+. 

I would be very grateful for any help and assistance from anybody with knowledge or experience in correcting vibration issues such as the one I described above

 

Thanks

 

Tom

 

--0-1569367839-1305820465=:32559--