X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.4.5) with ESMTP id 5600502 for flyrotary@lancaironline.net; Thu, 14 Jun 2012 19:07:17 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=2.0 cv=U/AQ/JXu c=1 sm=0 a=g3L/TDsr+eNLfIieSKfGkw==:17 a=AHkS0RJitIMA:10 a=0OLOLNd6atUA:10 a=05ChyHeVI94A:10 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=3oc9M9_CAAAA:8 a=oCcaPWc0AAAA:8 a=3sPFRjWZC0AtK3q96CkA:9 a=wPNLvfGTeEIA:10 a=U8Ie8EnqySEA:10 a=l3AgVJ6Y3NhLvyxc:21 a=M4nfJsDuYDUuzE89:21 a=glYVDZ00AAAA:8 a=Ia-xEzejAAAA:8 a=o9KuFcxMAAAA:8 a=4PR2P7QzAAAA:8 a=qVjmkuvqIEQL615uVGkA:9 a=_W_S_7VecoQA:10 a=XCwpvLtFMdsA:10 a=EzXvWhQp4_cA:10 a=GhIjh3UBWcwA:10 a=djSSOgbfo6cA:10 a=g3L/TDsr+eNLfIieSKfGkw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.170.10 Received: from [174.110.170.10] ([174.110.170.10:56293] helo=EdPC) by cdptpa-oedge01.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 5D/76-07841-18E6ADF4; Thu, 14 Jun 2012 23:06:41 +0000 Message-ID: <414BDA42BAC04742AEEE18AEF8F7B9F4@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: IVO Prop controls Date: Thu, 14 Jun 2012 19:06:28 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002A_01CD4A60.CD237020" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_002A_01CD4A60.CD237020 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sorry, Chris, Gave the hardware away to go with the prop in case it ever went further = than it did. It was a great concept and got to the 11th hour, but = couldn't make the push over the top. =20 Besides, I think you've had enough of dealing with the many problems = that arise in any project {:>) Ed From: Chris Barber=20 Sent: Thursday, June 14, 2012 5:25 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: IVO Prop controls Gee Ed, if ya want a proof of concept bird, I am testing anyway :-) Chris Sent from my iPhone 4 On Jun 14, 2012, at 11:30 AM, "Ed Anderson" = wrote: Back a few years ago, there was a variable pitch prop hub designed by = a genus of a mechanical engineer. It had a pitch control mechanism = similar to the IVO adjustable pitch prop. I designed a control circuit = which among other things monitored the current draw of the pitch motor. = While the prop project was not completed (to the best of my = knowledge), I found it was possible by conducting some test = measurements to correlate the current draw curve to propeller pitch. = Now the missing part was - we never got to the point of installing and = running the prop using the controller. Its highly likely that the = current curve would be different under air loads than not. We did not = use a meter but instead had the current turn on an LED (red) when the = limit was hit. =20 One of the things that I had planned to do was incorporate a manifold = pressure input (as well as prop rpm) to automatically adjust to prop = pitch to maintain rpm under various loading. The hardware to do so was = completed and the software - just never got tested. Just found some of the old code begin //Main RPM_Limit_Low :=3D 3000; RPM_Limit_High:=3D 7000; RPM_TO :=3D 5800; RPM_CC :=3D 5600; RPM_CR :=3D 5200; RPM_DC :=3D 5500; //Put address of varible RPM_TO into Pointer variable PORTB.RB0 :=3D 1; //set to enter while loop in procedure While testbit(INTCON,RBIF) =3D 0 do I now recall that we actually had several target settings such as TO = (Take off), CC (Cruise Climb), CR (Cruise Range), and others for various = flight regimes. So you could choose TO, CC, CR or DC from a menu and = the prop was pitch was positioned/adjusted to maintain the rpm. = Manifold pressure was also a factor. Also it had direction LEDs so you = could select to manuall/electrically increase or decrease pitch and a = bunch of other things I have now forgotten. You could adjust those rpm = values that best suited your particular aircraft/engine combination - = the preset values were intended to reduce the pilot work load. I was programming a PIC 18F450 chip to handle the control and sensor = inputs and provide a user interface on an LCD display with buttons. It would have been great had the prop project gone on to completion, = but alas despite the best efforts of a number of good folks it did not. Ed Edward L. Anderson Anderson Electronic Enterprises LLC 305 Reefton Road Weddington, NC 28104 http://www.andersonee.com http://www.eicommander.com From: Chad Robinson=20 Sent: Wednesday, June 13, 2012 5:52 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: IVO Prop controls I think there's a miscommunication about how this device works. It's = quite simple: two commutator brushes on a fixed arm transfer current = into the prop hub to engage the motor and twist the prop blades. Like = most motors/actuators, you wire it such that positive voltage is applied = to turn it one way, negative turns it the other, and while not moving = there is no voltage applied. A simple (ON)-OFF-(ON) switch drives this. There are only two brushes so there's no way to transfer an at-limit = signal, and although I'm just guessing here, a reliable pair of limit = switches that can operate properly inside the prop at full RPM would = have been complicated/maybe unreliable? They'd also be a pain to adjust. Anyway, the motor draws only a moderate amount of current in the = middle of its travel, and this increases as you approach the limits. = Standard practice is to install a meter to indicate this draw and it = tells you when you're near the limit. You could install a PTC instead of a breaker, but it's hardly an = emergency. It's not actually SOP to run it that far - in the times I've = flown with John I don't recall him ever doing it except perhaps once to = show me what happens. You don't "run it until it pops." You "run it = until it's where you want it to be." So PTC or breaker, it doesn't = really make that much of a difference. Choose the safety device you = prefer. I don't understand the bit about the shorted switch. That's pretty = rare, and the breaker would deal with it just fine. And I can't speak = for anybody else, but every car I've ever owned doesn't use a PTC to set = the travel limit on the window, it uses a limit switch on the actuator. = I recall having to adjust mine one time in a Subaru, just like the nose = gear travel switches in a Cozy. Besides, what's the down side here? You short your switch and the = breaker will deal with it, and the prop will stop twisting. No matter = WHICH device you use, in this case you now have no way to move the prop = because a short would hold a PTC open and also keep tripping a breaker = when you manually reset that. Both devices have the same failure mode if = it's the switch that's the problem. But you still have a working prop = even if it's not at the optimal pitch. See if you can jiggle the switch = to clear the short... To each his own. Regards, Chad On 6/13/12 5:15 PM, Lehanover@aol.com wrote:=20 Why in the world would IVO use a device that is designed to fail = critical flight gear in the case of improper control manipulation when they don't have to? Isn't this the classical and = proper application for a polyfuse? Polyfuses are used in power windows for this exact reason. You're kids can pull on = that switch all day without damaging the window motor. I'm thinking of the case where a switch gets shorted (like my = belt sander's switch is right now...the power cord is serving as a temp fix until I get time), or someone accidentally = leans something against the switch. Why does the motor draw current after the pitch has been changed? Lynn E. Hanover=20 No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2180 / Virus Database: 2433/5068 - Release Date: = 06/13/12 No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2180 / Virus Database: 2433/5070 - Release Date: = 06/14/12 ------=_NextPart_000_002A_01CD4A60.CD237020 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Sorry, Chris,
 
Gave the hardware away to go with the prop in = case it ever=20 went further than it did.  It was a great concept and got to the = 11th hour,=20 but couldn't make the push over the top. 
 
Besides, I think you've had enough of dealing = with the=20 many problems that arise in any project {:>)
 
Ed

Sent: Thursday, June 14, 2012 5:25 PM
Subject: [FlyRotary] Re: IVO Prop controls

Gee Ed, if ya want a proof of concept bird, I am testing anyway = :-)

Chris

Sent from my iPhone 4

On Jun 14, 2012, at 11:30 AM, "Ed Anderson" <eanderson@carolina.rr.com&g= t;=20 wrote:

Back a few years ago, there was a variable = pitch prop=20 hub designed by a genus of a mechanical engineer.  It had a pitch = control=20 mechanism similar to the IVO adjustable pitch prop.  I designed a = control=20 circuit which among other things monitored the current draw of the = pitch=20 motor. 
 
While the prop project was not completed (to = the best of=20 my knowledge), I found it was  possible by conducting some = test=20 measurements to correlate the current draw curve to propeller = pitch.  Now=20 the missing part was -  we never got to the point of installing = and=20 running the prop using the controller.  Its highly likely that = the=20 current curve would be different under air loads than not.  We = did not=20 use a meter but instead had the current turn on an LED (red) when the = limit=20 was hit. 
 
One of the things that I had planned to do was = incorporate a manifold pressure input (as well as prop rpm) to = automatically=20 adjust to prop pitch to maintain rpm under various loading.  The = hardware=20 to do so was completed and the software - just never got = tested.
 
Just found some of the old code
 
begin  //Main
 
   RPM_Limit_Low :=3D=20 3000;
    RPM_Limit_High:=3D 7000;
 
    RPM_TO :=3D = 5800;
   =20 RPM_CC :=3D 5600;
    RPM_CR :=3D = 5200;
   =20 RPM_DC :=3D 5500;
    //Put address of varible = RPM_TO into=20 Pointer variable
    PORTB.RB0 :=3D 1; //set to = enter while=20 loop in procedure
While testbit(INTCON,RBIF) =3D 0 = do
 
I now recall that we actually had several = target=20 settings such as TO (Take off), CC (Cruise Climb), CR (Cruise Range), = and=20 others for various flight regimes.  So you could choose TO, CC, = CR or DC=20 from a menu and the prop was pitch was positioned/adjusted to maintain = the=20 rpm.  Manifold pressure was also a factor.  Also it had = direction=20 LEDs so you could select to manuall/electrically increase or decrease = pitch=20 and a bunch of other things I have now forgotten.  You could = adjust those=20 rpm values that best suited your particular aircraft/engine = combination - the=20 preset values were intended to reduce the pilot work = load.
 
I was programming a PIC 18F450 chip to handle = the=20 control and sensor inputs and provide a user interface on an LCD = display with=20 buttons.
 
It would have been great had the prop project = gone on to=20 completion, but alas despite the best efforts of a number of good = folks it did=20 not.
 
Ed
 
Edward L. Anderson
Anderson Electronic = Enterprises=20 LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com
 
 
 
 

From: Chad=20 Robinson
Sent: Wednesday, June 13, 2012 5:52 PM
Subject: [FlyRotary] Re: IVO Prop = controls

I think there's a miscommunication about how this = device works.=20 It's quite simple: two commutator brushes on a fixed arm transfer = current into=20 the prop hub to engage the motor and twist the prop blades. Like most=20 motors/actuators, you wire it such that positive voltage is applied to = turn it=20 one way, negative turns it the other, and while not moving there is no = voltage=20 applied. A simple (ON)-OFF-(ON) switch drives this.

There are = only two=20 brushes so there's no way to transfer an at-limit signal, and although = I'm=20 just guessing here, a reliable pair of limit switches that can operate = properly inside the prop at full RPM would have been complicated/maybe = unreliable? They'd also be a pain to adjust.

Anyway, the motor = draws=20 only a moderate amount of current in the middle of its travel, and = this=20 increases as you approach the limits. Standard practice is to install = a meter=20 to indicate this draw and it tells you when you're near the = limit.

You=20 could install a PTC instead of a breaker, but it's hardly an = emergency. It's=20 not actually SOP to run it that far - in the times I've flown with = John I=20 don't recall him ever doing it except perhaps once to show me what = happens.=20 You don't "run it until it pops." You "run it until it's where you = want it to=20 be." So PTC or breaker, it doesn't really make that much of a = difference.=20 Choose the safety device you prefer.

I don't understand the bit = about=20 the shorted switch. That's pretty rare, and the breaker would deal = with it=20 just fine. And I can't speak for anybody else, but every car I've ever = owned=20 doesn't use a PTC to set the travel limit on the window, it uses a = limit=20 switch on the actuator. I recall having to adjust mine one time in a = Subaru,=20 just like the nose gear travel switches in a Cozy.

Besides, = what's the=20 down side here? You short your switch and the breaker will deal with = it, and=20 the prop will stop twisting. No matter WHICH device you use, in this = case you=20 now have no way to move the prop because a short would hold a PTC open = and=20 also keep tripping a breaker when you manually reset that. Both = devices have=20 the same failure mode if it's the switch that's the problem. But you = still=20 have a working prop even if it's not at the optimal pitch. See if you = can=20 jiggle the switch to clear the short...

To each his=20 own.

Regards,
Chad

On 6/13/12 5:15 PM, Lehanover@aol.com wrote:=20
Why in the world would IVO use a device that is = designed=20 to fail critical flight gear in the case of improper = control
manipulation=20 when they don't have to? Isn't this the classical and proper = application for=20 a polyfuse? Polyfuses are
used in power windows for this exact = reason.=20 You're kids can pull on that switch all day without damaging the=20 window
motor. I'm thinking of the case where a switch gets = shorted (like=20 my belt sander's switch is right now...the power cord
is serving = as a=20 temp fix until I get time), or someone accidentally leans something = against=20 the switch.
Why does the motor draw current after the pitch has been = changed?
 
Lynn E. Hanover 

No virus found in = this=20 message.
Checked by AVG - www.avg.com
Version: 2012.0.2180 / = Virus=20 Database: 2433/5068 - Release Date: = 06/13/12

No virus found in this=20 message.
Checked by AVG - www.avg.com
Version: 2012.0.2180 / = Virus=20 Database: 2433/5070 - Release Date: 06/14/12

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