X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 15 Aug 2011 07:40:59 -0400 Message-ID: X-Original-Return-Path: Received: from raven.ravenwebhosting.com ([72.9.254.67] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTPS id 5091930 for lml@lancaironline.net; Sun, 14 Aug 2011 18:48:23 -0400 Received-SPF: none receiver=logan.com; client-ip=72.9.254.67; envelope-from=paul@tbm700.com Received: from s01060017ee00b6c0.cg.shawcable.net ([174.0.115.173]:50956 helo=[192.168.15.11]) by raven.ravenwebhosting.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.69) (envelope-from ) id 1QsjTA-0006wK-QD for lml@lancaironline.net; Sun, 14 Aug 2011 18:47:49 -0400 From: paul miller Content-Type: multipart/alternative; boundary=Apple-Mail-18-47401711 Subject: Prop Balancing: Legacy X-Original-Date: Sun, 14 Aug 2011 18:47:30 -0400 X-Original-Message-Id: <9292FE21-9A88-4E2A-B452-5C8D040BD3B4@tbm700.com> X-Original-To: Lancair Mailing List Mime-Version: 1.0 (Apple Message framework v1084) X-Mailer: Apple Mail (2.1084) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - raven.ravenwebhosting.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tbm700.com X-Source: X-Source-Args: X-Source-Dir: --Apple-Mail-18-47401711 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Prior to my trip back to Calgary I wanted to get rid of a nasty = vibration. My last A&P actually made the balance worse and now that I = see the results I think it was 180 degrees out of phase. At 2300 rpm I = had a nasty shake. At Oshkosh I bought the simple Dynavibe unit from Spruce on sale. Short = story is I wasted a day misreading the procedure. In essence, you = measure "in the direction of prop direction" and I was moving the prop = in that direction to get the balance position. However, once that was = understood, I was able to get my prop dialed in from 0.63 to 0.03 in = fast order. It would not be hard to go further with a miniature weight = change but I wanted to fly. These are photos of the setup. If you ever decide to do this, it is = easy on the Legacy. You can mount everything on the inside of the cowl = which allows the runs to be made with cowls on. It also means leaving = all the cables in place when changing weights. I used temporary weights = on the spinner exterior to narrow things down form 0.63 to 0.16 which = took 4 large washers and about 16g net added weight on the spinner. At = that point, it only took two small washers (the type that are used to = fasten the spinner) to bring it down to 0.03. The final changes are = very very sensitive. By moving the last weights from one spinner screw = to another you can easily home in on the exact spot for final weight. That final weight was permanently installed on the spinner back and the = final weight was adjusted for the gram-inches between the final radius = and the temporary spinner radius. It worked out darn close. The = Dynavibe is not a feature rich machine but it does work well. I had no = problems. You must guess at the initial test weights but it only takes = a few quick runs to dial things in. It provides IPS at X degrees. = Simple. I made some brackets with spare parts sitting in the hangar. I = taped the cables to the airframe using 3M blue painter tape which held = during runup but pulled off clean. I coiled the wires on top of the = cowl so I could remove the cowl without disconnecting all the cables = each time. Big time saver. When my final weight was installed on the = spinner back plate I did a final run to verify the results and then = removed all the gear. The resulting 2000 miles back to Calgary was a big improvement. Whereas = I could not really cruise at 2300 before, it was now quite smooth. I = would recommend the procedure to anyone who wants to check out their = balance or verify an existing balance weight or remove a vibration. I = would note that the weights installed by Hartzell on the hub underneath = the spinner are NOT changed or tampered with. You can play the slideshow here Paul=20 Legacy Calgary= --Apple-Mail-18-47401711 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii Prior = to my trip back to Calgary I wanted to get rid of a nasty vibration. =   My last A&P actually made the balance worse and now that I = see the results I think it was 180 degrees out of phase.  At 2300 = rpm I had a nasty shake.

At Oshkosh I bought the = simple Dynavibe unit from = Spruce on sale.  Short story is I wasted a day misreading = the procedure.  In essence, you measure "in the direction of prop = direction" and I was moving the prop in that direction to get the = balance position.   However, once that was understood, I was able = to get my prop dialed in from 0.63 to 0.03 in fast order.  It would = not be hard to go further with a miniature weight change but I wanted to = fly.

These are photos of the setup.  If = you ever decide to do this, it is easy on the Legacy.   You can mount everything on the = inside of the cowl which allows the runs to be made with = cowls on.  It also means leaving all the cables in place when = changing weights. I used temporary weights on the spinner exterior to = narrow things down form 0.63 to 0.16 which took 4 large washers and = about 16g net added weight on the spinner.  At that point, it only = took two small washers (the type that are used to fasten the spinner) to = bring it down to 0.03.  The final changes are very very sensitive. = By moving the last weights from one spinner screw to another you can = easily home in on the exact spot for final = weight.

That final weight was permanently = installed on the spinner back and the final weight was adjusted for the = gram-inches between the final radius and the temporary spinner radius. =  It worked out darn close.   The Dynavibe is not a feature = rich machine but it does work well.  I had no problems.   You = must guess at the initial test weights but it only takes a few quick = runs to dial things in.  It provides IPS at X degrees.   = Simple.  I made some brackets with spare parts sitting in the = hangar.  I taped the cables to the airframe using 3M blue painter = tape which held during runup but pulled off clean.  I coiled the = wires on top of the cowl so I could remove the cowl without = disconnecting all the cables each time.  Big time saver.  When = my final weight was installed on the spinner back plate I did a final = run to verify the results and then removed all the = gear.

The resulting 2000 miles back to Calgary = was a big improvement.  Whereas I could not really cruise at 2300 = before, it was now quite smooth.  I would recommend the procedure = to anyone who wants to check out their balance or verify an existing = balance weight or remove a vibration.  I would note that the = weights installed by Hartzell on the hub underneath the spinner are NOT = changed or tampered with.

You can play the slideshow here

Paul = ;
Legacy
Calgary
= --Apple-Mail-18-47401711--