X-Virus-Scanned: clean according to Sophos on Logan.com From: Received: from mail-qt0-f172.google.com ([209.85.216.172] verified) by logan.com (CommuniGate Pro SMTP 6.2c1) with ESMTPS id 9599853 for flyrotary@lancaironline.net; Thu, 23 Mar 2017 06:16:30 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.216.172; envelope-from=rwstracy@gmail.com Received: by mail-qt0-f172.google.com with SMTP id n21so171142390qta.1 for ; Thu, 23 Mar 2017 03:16:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:mime-version:to:from:subject:date:importance:in-reply-to :references; bh=FkSfUbRxQv42CadzKl/jgBQhzPhtLQ9p00voRb6gdS4=; b=Aw0v7KIWAI6G60LStVa57dNd/RIsLvseJtGVUceAt3cAwzTMEWC0iMmMWpyX7I63fF //lx4fMLzz4m35/MQYoII2ZSTJfODRNqSwuI2ESKw2ljjYvqkT2FZeSYiEG8QIC5YJcJ Zn+gaXaUBm7bfwV9yftODW5N3ObTeQPZUMGX5WO5cESNbqWlxOsXWjAAN9aVSDIG6zXU vG82Jsrx5wQb3MTEJg81kHZpgEHRqfBLqbEgu1oEZN5eIoKBOiQa2D6qDUOhru4dYMJg 2x0Dm4jCqvoqRqLiNQqtM27ZhjPi+/00RABASydA8UyZ/u+9wu0y3eZnfuX60CspX3op cpAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:mime-version:to:from:subject:date :importance:in-reply-to:references; bh=FkSfUbRxQv42CadzKl/jgBQhzPhtLQ9p00voRb6gdS4=; b=Og54XWyS1TPsvG4QC12kA6634zkxsnPDc5Qf9Xkq/bTNsk00FGX+hG5eaTmC+dGcva JWze+JIOA34HLarKZDDKrlniR9lzjA2D19pA3OMwHNQHcFC2cOPnyzwVoXtF4GT7TIod /YK35oA/sOuM5oI8zyFAkdglMLMJOgDKJmF43499/q81QlaQiy+jQdz8/rxye22CvZBP zTDjLF870tbE1VAzpEAvaM6wsbcnSfHb0RxpPfrxe8iO3YQYlrTzg+uHQTmctRGeJKwI /Sx+6JxNgl8mphuodtC8+xi4I9z6IHQ0XbcbZCfJEOc/vlqDdlh4c+KIKOQW8FUOhRYE 86bQ== X-Gm-Message-State: AFeK/H3uZtddauY7BhIs7z1FuYbly192PcxfRKHinpsCVE6lEajQYONa2BgPzQOx4HuLsw== X-Received: by 10.200.34.113 with SMTP id p46mr1335096qtp.38.1490264172028; Thu, 23 Mar 2017 03:16:12 -0700 (PDT) Return-Path: Received: from ?IPv6:::ffff:192.168.254.5? (h224.112.131.174.dynamic.ip.windstream.net. [174.131.112.224]) by smtp.gmail.com with ESMTPSA id c6sm2911336qte.30.2017.03.23.03.16.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Mar 2017 03:16:10 -0700 (PDT) Message-ID: <58d3a06a.8635ed0a.a5e5.fdd6@mx.google.com> MIME-Version: 1.0 To: William Jepson Subject: RE: [FlyRotary] Re: redrive options Date: Thu, 23 Mar 2017 06:16:08 -0400 Importance: normal X-Priority: 3 In-Reply-To: References: Content-Type: multipart/alternative; boundary="_EE0A2F47-4E79-4D63-B10F-AD47110CB7B4_" --_EE0A2F47-4E79-4D63-B10F-AD47110CB7B4_ Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Hi Bill, This is the first I=E2=80=99ve heard of Dave=E2=80=99s gear drive having= a burned bearing. If Dave is around I=E2=80=99d like to know which bearin= g and any other relevant information, operating RPM, turbo boost on the eng= ine, etc. If you have any details Bill, let me know. Tracy Sent from Mail for Windows 10 From: William Jepson Sent: Tuesday, March 21, 2017 8:13 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: redrive options Charlie, No they build a complete gearbox using planetary gears first. (spur only so= no end thrust) They found as you ran the engine through various speed rang= es it was possible to incur damage due to second order vibrations that coul= d be just as damaging. Sorry Charlie, but if you think their work was an un= necessary rabbit hole I won't be flying in your plane. That isn't intended = to be insulting. I just have seen the results of not handling these forces.= Dave Lenard flew his RV-6 behind Tracy's gearbox at Reno qualifying and to= tally torched the internal bearings. Regarding the transmission locked in g= ear, I wouldn't stand near the plane that was using the gearbox regardless = of the time he had on it. It was a disaster waiting to happen. Everyone thi= nks this is easy. You can get away with it for a while but if you want to u= se your engine at a significant HP level, for a cross country flight that y= ou intend to return from in the same plane, you MUST account for torsional = vibration. The math isn't terribly tough nor are the parts a lot heavier, b= ut the close meshing gears and stiff model never had a problem. They had to= properly support the pinion gear, and after that the thing was bullet proo= f. That can't be said about any of the other reduction boxes I have seen th= at are even close to the same weight. The guys built a beautiful torsional = dampener into a rotary e-shaft that worked perfectly with a planetary, it j= ust required too much expensive machining. Your comment about in resonance = problems being regardless of power level is true. Fortunately you can usual= ly transition the specific rpm without a lot of damage, but if you spend an= y time there even at idle you are going to break parts. I am tired of peopl= e thinking an auto conversion is too easy and then dead sticking their plan= e in a field somewhere. (As a best case) The base engines are rarely the pr= oblem. Automotive engines are built pretty well today, but a broken gearbox= , or drive belt, or torque converter, or flex plate, or clutch disk can sti= ll spoil your whole day. Bill Jepson On Tue, Mar 21, 2017 at 2:15 PM, Charlie England wrote: Uh, that wasn't me. :-) But I've heard the case made that exactly what you describe is what happene= d (dyno designed for V-8s at 4per-rev; twice the excitation frequency). I d= idn't stay in a Holiday Inn last night, but those who did tell me that *in = resonance*, power level doesn't really matter much; stuff is going to break= . I'd love to see that same driveshaft & dyno hooked to something like a bi= g 4cyl engine (2per-rev) capable of the same HP & rpm where their failure o= ccurred. Doesn't it make you wonder if the results would have been the same= ? One of our former members (since deceased due to natural causes) flew succe= ssfully for years using a Mazda transmission as a reduction drive. Worked g= reat until one day when the engine started on only one rotor (1per-rev) & *= at idle power* it destroyed the gearbox. I can't help but wonder if that dyno incident took them down an unnecessary= rabbit hole of expensive zero-clearance gears & extra weight. Charlie On 3/21/2017 3:51 PM, William Jepson wrote: Charlie,=20 In terms of simple vibration caused by out of balance you are correct. It t= erms of torsional vibration though the rotary is a tough customer. Part of = the problem is that the e-shaft on the rotary is so stiff. I have been work= ing with Steve Beckham from the original PowerSport. Steve told me about ho= w a 200 HP rotary just blew up the input shaft on a dyno that was regularly= used to test 600+ HP V8 piston engines. This is the torque pulses of the e= ngine, not out-of-balance. It is likely that in that case the rotary hit a = amplifying couple or harmonic frequency with the dyno causing the failure. = That said Steve and Everett Hatch did a LOT of work to be sure their "stiff= " model reduction drive placed all the frequencies above the normal operati= ng range. If you hit one of those frequencies with one of the rubber coupli= ngs or the bushing-around-bolt dampers it will fail period. Most of those s= ystems try to push the first order frequency below the operating range. Tha= t is why you will often hear the engine shut down rattle with a planetary. = Typically the energy in the system is low enough to pass through that RPM w= ithout damage. Usually. But if not planned for those pulses can be a disast= er. Bill Jepson On Tue, Mar 21, 2017 at 10:40 AM, cozygirrrl = wrote: Rotary torque pulses can be very destructive before buying anything specifi= cally=E2=80=8B mention the rotary. If they know anything they will be worri= ed. Bill Jepson Somebody please correct me if I am wrong but I have understood the opposite= , the rotary engine does not have the 4 bangs per prop revolution of a trad= itional 4 cylinder aircraft engine which shows as a spiky positive and nega= tive graph when plotted.=20 The output of the rotary is always positive torque in nature and overlappin= g sinusoidal due to the two rotors when the output wave forms are plotted, = hence the smoothness of the rotary. When peak output is plotted it shows an= always positive gentle wave. Chrissi=20 CG Products=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=20 www.CozyGirrrl.com=20 =C2=A0 -----Original Message----- From: William Jepson To: Rotary motors in aircraft Sent: Mon, Mar 20, 2017 7:02 pm Subject: [FlyRotary] Re: redrive options Rotary torque pulses can be very destructive before buying anything specifi= cally=E2=80=8B mention the rotary. If they know anything they will be worri= ed. Bill Jepson On Mar 20, 2017 3:48 PM, "drhyed" wrote: I had brief conversation with them last fall and they designed the gearbox = with the intention of offering higher horsepower options: "We do have plans for a higher horsepower engine.=C2=A0 When we designed ou= r gearbox we intended to do engines to about 225 hp from the start. Our intent is to do a 155 hp normally aspirated 2 liter and a 200 hp turbo = version" I did not mention a rotary engine specifically though. Jay On Mar 20, 2017, at 5:31 PM, Charlie England = wrote: These guys have been advertising on ebay for a while. I have no idea about = whether they are legit, or whether the drive is suitable for a rotary. The = web page claims 'good up to 225HP', but their target installations are clos= er to half that, so.... http://www.aeromomentum.com/partslist.html Charlie --_EE0A2F47-4E79-4D63-B10F-AD47110CB7B4_ Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8"

Hi Bill,

=C2= =A0=C2=A0 This is the first I=E2=80=99ve heard of Dave=E2=80=99s gear drive= having a burned bearing.=C2=A0 If Dave is around I=E2=80=99d like to know = which bearing and any other relevant information, operating RPM, turbo boos= t on the engine, etc.=C2=A0 If you have any details Bill, let me know.

<= p class=3DMsoNormal> 

Tracy

 

Sent from Mail for Windows= 10

 

From: = William Jepson
Sent: Tuesday, March 21, 2017 8:13 PM
To: Rotary motors in aircraft
Subject: <= /b>[FlyRotary] Re: redrive options

 = ;

Charlie,

= No they build a complete gearbox using planetary gears first. (spur only so= no end thrust) They found as you ran the engine through various speed rang= es it was possible to incur damage due to second order vibrations that coul= d be just as damaging. Sorry Charlie, but if you think their work was an un= necessary rabbit hole I won't be flying in your plane. That isn't intended = to be insulting. I just have seen the results of not handling these forces.= Dave Lenard flew his RV-6 behind Tracy's gearbox at Reno qualifying and to= tally torched the internal bearings. Regarding the transmission locked in g= ear, I wouldn't stand near the plane that was using the gearbox regardless = of the time he had on it. It was a disaster waiting to happen. Everyone thi= nks this is easy. You can get away with it for a while but if you want to u= se your engine at a significant HP level, for a cross country flight that y= ou intend to return from in the same plane, you MUST account for torsional = vibration. The math isn't terribly tough nor are the parts a lot heavier, b= ut the close meshing gears and stiff model never had a problem. They had to= properly support the pinion gear, and after that the thing was bullet proo= f. That can't be said about any of the other reduction boxes I have seen th= at are even close to the same weight. The guys built a beautiful torsional = dampener into a rotary e-shaft that worked perfectly with a planetary, it j= ust required too much expensive machining. Your comment about in resonance = problems being regardless of power level is true. Fortunately you can usual= ly transition the specific rpm without a lot of damage, but if you spend an= y time there even at idle you are going to break parts. I am tired of peopl= e thinking an auto conversion is too easy and then dead sticking their plan= e in a field somewhere. (As a best case) The base engines are rarely the pr= oblem. Automotive engines are built pretty well today, but a broken gearbox= , or drive belt, or torque converter, or flex plate, or clutch disk can sti= ll spoil your whole day.

Bill Jepson

=

 

On Tue, Mar 21, 2017 at 2:15 PM, Charlie England <flyrotary@lancaironlin= e.net> wrote:

Uh, that wasn't me. :-)

But I've hea= rd the case made that exactly what you describe is what happened (dyno desi= gned for V-8s at 4per-rev; twice the excitation frequency). I didn't stay i= n a Holiday Inn last night, but those who did tell me that *in resonance*, = power level doesn't really matter much; stuff is going to break. I'd love t= o see that same driveshaft & dyno hooked to something like a big 4cyl e= ngine (2per-rev) capable of the same HP & rpm where their failure occur= red. Doesn't it make you wonder if the results would have been the same?
One of our former members (since deceased due to natural causes) flew = successfully for years using a Mazda transmission as a reduction drive. Wor= ked great until one day when the engine started on only one rotor (1per-rev= ) & *at idle power* it destroyed the gearbox.

I can't help but w= onder if that dyno incident took them down an unnecessary rabbit hole of ex= pensive zero-clearance gears & extra weight.

Charlie



On 3/21/2017 3:51 PM, William Jepson wrote:=

Charlie,

In terms of simple vibration caused by out of balance you are correct= . It terms of torsional vibration though the rotary is a tough customer. Pa= rt of the problem is that the e-shaft on the rotary is so stiff. I have bee= n working with Steve Beckham from the original PowerSport. Steve told me ab= out how a 200 HP rotary just blew up the input shaft on a dyno that was reg= ularly used to test 600+ HP V8 piston engines. This is the torque pulses of= the engine, not out-of-balance. It is likely that in that case the rotary = hit a amplifying couple or harmonic frequency with the dyno causing the fai= lure. That said Steve and Everett Hatch did a LOT of work to be sure their = "stiff" model reduction drive placed all the frequencies above th= e normal operating range. If you hit one of those frequencies with one of t= he rubber couplings or the bushing-around-bolt dampers it will fail period.= Most of those systems try to push the first order frequency below the oper= ating range. That is why you will often hear the engine shut down rattle wi= th a planetary. Typically the energy in the system is low enough to pass th= rough that RPM without damage. Usually. But if not planned for those pulses= can be a disaster.

Bill Jepson

 

On Tue, Mar 21, 2017 at 10:40 AM, cozygirrrl <flyrotary@lancaironline.net= > wrote:

 

Rotary torque pulses can be very destructive before buying anyt= hing specifically=E2=80=8B mention the rotary. If they know anything they w= ill be worried.

Bill Jepso= n

<= span style=3D'font-size:10.0pt;font-family:"Arial",sans-serif;color:black'>=  

Somebody please correct me if I am wrong but I have unders= tood the opposite, the rotary engine does not have the 4 bangs per prop rev= olution of a traditional 4 cylinder aircraft engine which shows as a spiky = positive and negative graph when plotted.
The output of the rotary is a= lways positive torque in nature and overlapping sinusoidal due to the two r= otors when the output wave forms are plotted, hence the smoothness of the r= otary. When peak output is plotted it shows an always positive gentle wave.=

Chrissi <= /span>

CG Products    &nb= sp; 

 

 = ;

 =

-----Or= iginal Message-----
From: William Jepson <flyrotary@lancaironline.net>To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon,= Mar 20, 2017 7:02 pm
Subject: [FlyRotary] Re: redrive options

Rotary torque pulses can be very destructive b= efore buying anything specifically=E2=80=8B mention the rotary. If they kno= w anything they will be worried.

Bill Jepson

 

On Mar 20, 2017 3= :48 PM, "drhyed" <flyrotary@lancaironline.net> wrote:<= /span>

I had brief conversation with them last fall and th= ey designed the gearbox with the intention of offering higher horsepower op= tions:

 

"We do have plans for a= higher horsepower engine.  When we designed our gearbox we intended t= o do engines to about 225 hp from the start.


Our intent is to do a 155 hp normally aspirated 2 li= ter and a 200 hp turbo version"

 

I did not mention a rotary engine specifically though.<= /p>

 

=

 

Jay


On Mar 20, 2017, at 5:31 PM, Charlie England <flyrotary@lancai= ronline.net> wrote:

These= guys have been advertising on ebay for a while. I have no idea about wheth= er they are legit, or whether the drive is suitable for a rotary. The web p= age claims 'good up to 225HP', but their target installations are closer to= half that, so....

&nb= sp;

 

Charlie

 

&n= bsp;

 

=

 =

 

= --_EE0A2F47-4E79-4D63-B10F-AD47110CB7B4_--