X-Junk-Score: 0 [] X-Cloudmark-Score: 0 [] X-Cloudmark-Analysis: v=2.3 cv=NIirBHyg c=1 sm=1 tr=0 a=XWSBf9a/bkSGQevdmJs33w==:117 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=x7bEGLp0ZPQA:10 a=ad1WmcueCrwA:10 a=oexKYjalfGEA:10 a=UKPAHat8AAAA:8 a=Ia-xEzejAAAA:8 a=pGLkceISAAAA:8 a=HZJGGiqLAAAA:8 a=hOful1X-QmnqIqmqve8A:9 a=QEXdDO2ut3YA:10 a=7AHqUDzecxQmb37NTOoA:9 a=TBMpx7L7HwxBiQQt:21 a=Fc6xXSS-RxGHxrvp76Qp:22 a=Urk15JJjZg1Xo0ryW_k8:22 From: "William Jepson wrjjrs@gmail.com" Received: from mail-ed1-f45.google.com ([209.85.208.45] verified) by logan.com (CommuniGate Pro SMTP 6.2.12) with ESMTPS id 12400652 for flyrotary@lancaironline.net; Tue, 02 Apr 2019 17:13:25 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.208.45; envelope-from=wrjjrs@gmail.com Received: by mail-ed1-f45.google.com with SMTP id d26so12938273ede.10 for ; Tue, 02 Apr 2019 14:13:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=/5zoRwjTgH9GDmiTJGdPkM5WRvP0Q91a6jDjRLyScIM=; b=PguTFnhULq744rGrdZvTIs/G5MfDAKxf2OgKkx1/R0wO0GFJ1Pc53bFyaZKBy7/eA8 LxgXMPMbkAtcI0052G6ZmJyJi1MyoI/I4WLH7UYXRpygShue5ug3+DYnrTE0FAqRwUEA SZG5Yl7qAPUIp7GmYcR/Q+Mi6qgBiDMuyQCGS8UHAgqqnv6916ZYhjm1rhQFoppIHTNQ IiFYqS23GCw3g/1GSRM3O8hAexvfmvh9NtGeFQFwetxXGEFyd7053tv2pE6k73rtBbde SxPOFsc1i/xniy0iez8NpAKgZnrrlwSqGUqmiWEtnIOs/hLAdDPlReyxKlwxt+YFKUN6 D7YQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=/5zoRwjTgH9GDmiTJGdPkM5WRvP0Q91a6jDjRLyScIM=; b=lnvh2VGpDGhG55vANDWd/OIq8ri7gDPK4MhJ71JNjUHX6zm2tB5fqRZWQat9V00n8M hAnZ3QMR1KiCGYxdP6ExqJ7is2gzdrskqNPRIzVUESh6CCD4LjkJ01mHx7iVds/0TbzI xFcPghmKp58FKkL8weE+WdzxvIQOL3g3/Tfh/2zDcQ2WzJh1edhizNr/gwHZBUv4p+B4 CeweOA+Y/fYaIKWYLVNy9AYxNCCE4CnNW4h/v6/8j1mTSvZlz+LL03B/uvbC9DF7GAsG J8Hj6WmrdvO++reQwGWbbNFkWVEn/LA5bs3utEoA1358AlhoyJdmR9Tgyn1lZ0kIakLY xkHA== X-Gm-Message-State: APjAAAUp9jc+lb09PpyJwouAiuo2VGGAptPRVfVxhT8ImZ9AKAibiKrI /RFBMUyZ6IPwWHMdSm+OtcH1bx554IoF8b+vdP2y3DqD X-Google-Smtp-Source: APXvYqzcSrIZ1ybdNHne+c57ToGhIsKcvL5hPkgomMB2TXYV9kxxIA3MPYXr+4QM6IXy9JAQXswxLKnuDf37NOLWJfA= X-Received: by 2002:a50:9856:: with SMTP id h22mr47521527edb.186.1554239586964; Tue, 02 Apr 2019 14:13:06 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Tue, 2 Apr 2019 14:12:56 -0700 Message-ID: Subject: Re: [FlyRotary] Re: Electric constant speed props To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="0000000000007a1a690585929a12" --0000000000007a1a690585929a12 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Bobby, You push it fairly hard with your supercharged engine too. What cruise RPM are you running? P.Sport always tried to tune for lower RPMS and higher power to avoid the torsional vibration problems. With boost you can make more power at lower RPMs which is a plus in this case. The rotary is tough, the engine will tolerate a lot, but the high revs for long periods is what causes the need for attention to torsionals. BTW I moved and had to take a break from my redrive efforts, but am getting back to it. Got some good ideas today from Mark Hatch, Everett's son. Bill On Tue, Apr 2, 2019 at 2:02 PM Bobby J. Hughes bhughes@qnsi.net < flyrotary@lancaironline.net> wrote: > > My MT weighs 42#=E2=80=99s. The hub is heavy, blades are light weigh. Gea= r lashing > appears to have increased a little over the first 500 hours. End play is > about 5 thousandths with original snubber. > > Bobby > > Sent from my iPad > > On Apr 2, 2019, at 3:48 PM, William Jepson wrjjrs@gmail.com < > flyrotary@lancaironline.net> wrote: > > 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 effec= t > your comfort on longer flights. Mufflers for rotaries are tough, I alread= y > 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 vibrati= on > 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, an= d > 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 wi= th > 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 cruis= e > 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 en= d > 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 > > On Tue, Apr 2, 2019 at 6:34 AM Samuel Hodges samueln462wp@att.net < > flyrotary@lancaironline.net> wrote: > >> Lately I have been considering an Airmaster electric constant speed pro= p >> 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. >> >> Sam >> RV-7A >> Renesis >> > --0000000000007a1a690585929a12 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Bobby, You push it fairly hard with your supercharged engi= ne too. What cruise RPM are you running? P.Sport always tried to tune for l= ower RPMS and higher power to avoid the torsional vibration problems. With = boost you can make more power at lower RPMs which is a plus in this case.= =C2=A0 The rotary is tough, the engine will tolerate a lot, but the high revs for = long periods is what causes the need for attention to torsionals. BTW I mov= ed and had to take a break from my redrive efforts, but am getting back to = it. Got some good ideas today from Mark Hatch, Everett's son.=C2=A0Bill

On Tue, Apr 2, 2019 at 2:02 PM Bobby J. Hughes bhughes@qnsi.net <flyrotary@lancaironline.net> wrote:

My MT= weighs 42#=E2=80=99s. The hub is heavy, blades are light weigh. Gear lashi= ng appears to have increased a little over the first 500 hours. End play is= about 5 thousandths with original snubber.=C2=A0

= Bobby

Sent from my iPad

On Apr 2, 2019,= at 3:48 PM, William Jepson wrjjrs@gmail.com <flyrotary@lancaironline.net> wrote:

Sam,
I a= m 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 Powe= rsport 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. To= rsional vibration issues also favored a wood prop. How heavy is the electri= c Airmaster? MOST en= gines including the rotary are helped by a variable pitch prop. Whether the= combination is safe depends on the reduction drive, ratio, and weight of t= he prop on the output shaft. Powersport's owners noted significant torsional vibration prob= lems with every planetary gear set, (even their own custom made straight cu= t planetary). Their later stiff model internal ring gear reduction gearbox = put the resonances out of the normal range for the rotary. Prior to that th= e 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 runn= ing a planetary reduction you need to keep the weight down as much as you c= an. Find out what the Airma= ster weighs. The amount that it exceeds your wood or carbon fixed bl= ade 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 probl= ems that aren't obvious as to origin. Torsional problems may take hundr= eds of hours to develop, or something may break the first week. Just be war= y. Always keep track of things like changes in output shaft end play and ba= cklash. You can make the change, and see excellent results but go in with y= our eyes open. Lots of people will tell you this is nervous nelly stuff, bu= t the guys at P.S. probably had more hours running and testing rotaries AT = HIGH OUTPUT levels than anyone other than Mazda.
Bill Jepson

On Tue, Apr 2, 201= 9 at 6:34 AM Samuel Hodges samueln462wp@att.net <flyrotary@lancaironline.net> wrote:
=C2=A0Lately I have been considering an Airmaster el= ectric constant speed prop to help achieve the rotaries true potential. I a= m 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.
<= br>
Sam
RV-7A
Renesis=C2=A0
=
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