X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.3 cv=NIirBHyg c=1 sm=1 tr=0 a=pclmDsHkpheh2ESL7sCqlg==:117 a=xycr6CVXJRVtFs4WRGOeRA==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=oexKYjalfGEA:10 a=DAwyPP_o2Byb1YXLmDAA:9 a=Ia-xEzejAAAA:8 a=HZJGGiqLAAAA:8 a=rGB9wef-5JX2b8rUHxAA:9 a=QEXdDO2ut3YA:10 a=yMhMjlubAAAA:8 a=SSmOFEACAAAA:8 a=suHSHD3_ZNT5XjrG:21 a=gKO2Hq4RSVkA:10 a=UiCQ7L4-1S4A:10 a=hTZeC7Yk6K0A:10 a=frz4AuCg-hUA:10 a=Urk15JJjZg1Xo0ryW_k8:22 a=Z5ABNNGmrOfJ6cZ5bIyy:22 a=UDnyf2zBuKT2w-IlGP_r:22 From: "Marc Wiese cardmarc@charter.net" Received: from [47.43.20.33] (HELO impout009.msg.chrl.nc.charter.net) by logan.com (CommuniGate Pro SMTP 6.2.12) with ESMTPS id 12400666 for flyrotary@lancaironline.net; Tue, 02 Apr 2019 17:36:46 -0400 Received-SPF: pass receiver=logan.com; client-ip=47.43.20.33; envelope-from=cardmarc@charter.net Received: from HomeDesktop ([97.94.202.172]) by cmsmtp with ESMTP id BR54hfSOsiYmuBR54hWqEP; Tue, 02 Apr 2019 21:36:30 +0000 Authentication-Results: charter.net; none X-Authority-Analysis: v=2.3 cv=S41tP7kP c=1 sm=1 tr=0 a=xycr6CVXJRVtFs4WRGOeRA==:117 a=xycr6CVXJRVtFs4WRGOeRA==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=DAwyPP_o2Byb1YXLmDAA:9 a=Ia-xEzejAAAA:8 a=HZJGGiqLAAAA:8 a=rGB9wef-5JX2b8rUHxAA:9 a=QEXdDO2ut3YA:10 a=yMhMjlubAAAA:8 a=SSmOFEACAAAA:8 a=suHSHD3_ZNT5XjrG:21 a=gKO2Hq4RSVkA:10 a=UiCQ7L4-1S4A:10 a=hTZeC7Yk6K0A:10 a=frz4AuCg-hUA:10 a=Urk15JJjZg1Xo0ryW_k8:22 a=Z5ABNNGmrOfJ6cZ5bIyy:22 a=UDnyf2zBuKT2w-IlGP_r:22 To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: Electric constant speed props Date: Tue, 2 Apr 2019 16:36:30 -0500 Message-ID: <004501d4e99c$22d3c1a0$687b44e0$@charter.net> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0046_01D4E972.3A000390" X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQLi00B9roAu1hGzjedc7XXlmBL2wKQNkHEw Content-Language: en-us X-CMAE-Envelope: MS4wfJChIxuWeuC+IQDzVAv1h3wcCCapDDCrdG32H43tACa+RELEmHQ5pIVfVmbA4TDimzCdCPubO98OKtDR8ddfcwRUNm87hv00yCnqh8Nqvjp1W2WXv3Fe txaaqjxxMRqDShFZol11C9KIHq2VgiEZWcAZcrCniEgYVN/+GD4FnyFnnpp8ggKsR0y2fUn/drG7Dg== This is a multipart message in MIME format. ------=_NextPart_000_0046_01D4E972.3A000390 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable There are composite CS electric props, they are showing up a lot on the = European LSA type planes lately. Whirlwind makes the blades? And MT = Hoffman make electric composite props too. A comp would weight much = less, depending on hub design. FWIW. Marc =20 From: Rotary motors in aircraft =20 Sent: Tuesday, April 02, 2019 2:48 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Electric constant speed props =20 Sam, I am working with some originators of Powersport. The weight of your = build makes a big difference on the use of a constant speed. Also in the = case of the rotary the quality of your muffler! Sound levels really = effect your comfort on longer flights. Mufflers for rotaries are tough, = I already have 1 failed design to my (bad) credit. The original = Powersport designs used the light weight and flexibility of a wood prop = to their advantage. Those engines were tuned for max power at 6500 RPM. = The reductions were about 1.85 to 2.2:1. suitable for the lower power = peak. Torsional vibration issues also favored a wood prop. How heavy is = the electric Airmaster? MOST engines including the rotary are helped by = a variable pitch prop. Whether the combination is safe depends on the = reduction drive, ratio, and weight of the prop on the output shaft. = Powersport's owners noted significant torsional vibration problems with = every planetary gear set, (even their own custom made straight cut = planetary). Their later stiff model internal ring gear reduction gearbox = put the resonances out of the normal range for the rotary. Prior to that = the only problem free build with a planetary was when they built a = pendulous damper system (like a big radial engine uses) which worked = great but was so expensive they figured they would never sell an engine. = So if you are running a planetary reduction you need to keep the weight = down as much as you can. Find out what the Airmaster weighs. The amount = that it exceeds your wood or carbon fixed blade prop is your risk = factor. The advantage is to use a low cruise rpm that takes advantage of = the props flexibility. As a thrust producing device it is better, there = is no doubt. If it is very heavy though it may cause problems that = aren't obvious as to origin. Torsional problems may take hundreds of = hours to develop, or something may break the first week. Just be wary. = Always keep track of things like changes in output shaft end play and = backlash. You can make the change, and see excellent results but go in = with your eyes open. Lots of people will tell you this is nervous nelly = stuff, but the guys at P.S. probably had more hours running and testing = rotaries AT HIGH OUTPUT levels than anyone other than Mazda. Bill Jepson =20 On Tue, Apr 2, 2019 at 6:34 AM Samuel Hodges samueln462wp@att.net = > wrote: Lately I have been considering an Airmaster electric constant speed = prop to help achieve the rotaries true potential. I am asking for = insight to help me make this decision. I'm not sure if the benefits of a = constant speed out weight the cost, please help. =20 Sam RV-7A Renesis=20 ------=_NextPart_000_0046_01D4E972.3A000390 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

There are composite CS electric = props, they are showing up a lot on the European LSA type planes lately. = Whirlwind makes the blades? And MT Hoffman make electric composite props = too. A comp would weight much less, depending on hub design. = FWIW.

Marc

 

From: Rotary motors in aircraft = <flyrotary@lancaironline.net>
Sent: Tuesday, April 02, = 2019 2:48 PM
To: Rotary motors in aircraft = <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: = Electric constant speed props

 

Sam,

I am = working with some originators of Powersport. The weight of your build = makes a big difference on the use of a constant speed. Also in the case = of the rotary the quality of your muffler! Sound levels really effect = your comfort on longer flights. Mufflers for rotaries are tough, I = already have 1 failed design to my (bad) credit. The original Powersport = designs used the light weight and flexibility of a wood prop to their = advantage. Those engines were tuned for max power at 6500 RPM. The = reductions were about 1.85 to 2.2:1. suitable for the lower power peak. = Torsional vibration issues also favored a wood prop. How heavy is the = electric Airmaster? MOST engines including the rotary are helped by a = variable pitch prop. Whether the combination is safe depends on the = reduction drive, ratio, and weight of the prop on the output shaft. = Powersport's owners noted significant torsional vibration problems with = every planetary gear set, (even their own custom made straight cut = planetary). Their later stiff model internal ring gear reduction gearbox = put the resonances out of the normal range for the rotary. Prior to that = the only problem free build with a planetary was when they built a = pendulous damper system (like a big radial engine uses) which worked = great but was so expensive they figured they would never sell an engine. = So if you are running a planetary reduction you need to keep the weight = down as much as you can. Find out what the Airmaster weighs. The amount = that it exceeds your wood or carbon fixed blade prop is your risk = factor. The advantage is to use a low cruise rpm that takes advantage of = the props flexibility. As a thrust producing device it is better, there = is no doubt. If it is very heavy though it may cause problems that = aren't obvious as to origin. Torsional problems may take hundreds of = hours to develop, or something may break the first week. Just be wary. = Always keep track of things like changes in output shaft end play and = backlash. You can make the change, and see excellent results but go in = with your eyes open. Lots of people will tell you this is nervous nelly = stuff, but the guys at P.S. probably had more hours running and testing = rotaries AT HIGH OUTPUT levels than anyone other than = Mazda.

Bill = Jepson

 

------=_NextPart_000_0046_01D4E972.3A000390--