X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-mb02.mx.aol.com ([64.12.207.163] verified) by logan.com (CommuniGate Pro SMTP 5.4.5) with ESMTP id 5599903 for flyrotary@lancaironline.net; Thu, 14 Jun 2012 13:39:53 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.207.163; envelope-from=ARGOLDMAN@aol.com Received: from mtaomg-da04.r1000.mx.aol.com (mtaomg-da04.r1000.mx.aol.com [172.29.51.140]) by imr-mb02.mx.aol.com (8.14.1/8.14.1) with ESMTP id q5EHd1MF028695 for ; Thu, 14 Jun 2012 13:39:01 -0400 Received: from core-dsb002c.r1000.mail.aol.com (core-dsb002.r1000.mail.aol.com [172.29.253.5]) by mtaomg-da04.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 1CEBBE000089 for ; Thu, 14 Jun 2012 13:39:01 -0400 (EDT) From: ARGOLDMAN@aol.com Message-ID: <31611.2f75d09e.3d0b7bb4@aol.com> Date: Thu, 14 Jun 2012 13:39:01 -0400 (EDT) Subject: Re: [FlyRotary] Re: IVO Prop controls To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_31611.2f75d09e.3d0b7bb4_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [24.14.64.174] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20110426; t=1339695541; bh=MDHTLxZHxgyaZQZ94iuSeK6FgN272Me28echdnQov+8=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=oKfDOyBKmhRCJ7jo2NkYIX1npA+svwZrpLCcZ4zRHjEMJGxc6lZcvuh/QUeCNGARd Z5oJ3/j+ytdksqMeQw2B0g1n+1gjMwlU2wHmSzr/3Mqzmh2m1EVO9xf0/+Svh5E1pf kUnVgOKseAUvSZcsTH08d2tsh6TFmCG0nZYe0dPc= X-AOL-SCOLL-SCORE: 0:2:491132480:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d338c4fda21b558a0 --part1_31611.2f75d09e.3d0b7bb4_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Ed, What a great idea, sorry it never made it to the general flying public. Ivo does, in fact have a C/S controller. Reading some posts, some are not happy with it and have removed it, much like some are unhappy with rotaries and have removed them, despite the success others are having. The ivo controller has a simple hall effect transducer which reads a magnet buried in one of the prop blades, or the spinner back plate, if a normal spinner is used (as opposed to the skull-cap that IVO sells). It does not use the amp draw of the blade change mechanism at all, to the best of my knowledge. The draw will disconnect if the physical limits are hit in the case of an error. The controller, electronically is set for max and min pitch via it's adjustments. Don't know about the circuitry or the programming-- haven't taken mine apart--yet. When engaged, and properly adjusted (several pots) the RPm is controlled by a knob, which obviously is a POT. there are switches (remotely mounted) to select manual pitch change or C/S. Rich In a message dated 6/14/2012 11:29:59 A.M. Central Daylight Time, eanderson@carolina.rr.com writes: 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. 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 := 3000; RPM_Limit_High:= 7000; RPM_TO := 5800; RPM_CC := 5600; RPM_CR := 5200; RPM_DC := 5500; //Put address of varible RPM_TO into Pointer variable PORTB.RB0 := 1; //set to enter while loop in procedure While testbit(INTCON,RBIF) = 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.andersonee.com/) _http://www.eicommander.com_ (http://www.eicommander.com/) From: _Chad Robinson_ (mailto:crobinson@medialantern.com) Sent: Wednesday, June 13, 2012 5:52 PM To: _Rotary motors in aircraft_ (mailto:flyrotary@lancaironline.net) 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_ (mailto:Lehanover@aol.com) wrote: 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 No virus found in this message. Checked by AVG - _www.avg.com_ (http://www.avg.com/) Version: 2012.0.2180 / Virus Database: 2433/5068 - Release Date: 06/13/12 --part1_31611.2f75d09e.3d0b7bb4_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Ed,
 
What a great idea, sorry it never made it to the general flying=20 public.
 
Ivo does, in fact have a C/S controller. Reading some posts, some are = not=20 happy with it and have removed it, much like some are unhappy with rotaries= and=20 have removed them, despite the success others are having.
 
The ivo controller has a simple hall effect transducer which reads a m= agnet=20 buried in one of the prop blades, or the spinner back plate, if a normal sp= inner=20 is used (as opposed to the skull-cap that IVO sells).
 
It does not use  the amp draw of the blade change mechanism at al= l, to=20 the best of my knowledge. The draw will disconnect if the physical limits a= re=20 hit in the case of an error. The controller, electronically is set for max = and=20 min pitch via it's adjustments.
 
Don't know about the circuitry or the programming-- haven't taken mine= =20 apart--yet. When engaged, and properly adjusted (several pots) the RPm is= =20 controlled by a knob, which obviously is a POT. there are switches (remotel= y=20 mounted) to select manual pitch change or C/S.
 
Rich
 
In a message dated 6/14/2012 11:29:59 A.M. Central Daylight Time,=20 eanderson@carolina.rr.com writes:
=
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 co= ntrol=20 mechanism similar to the IVO adjustable pitch prop.  I designed a co= ntrol=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 n= ot=20 use a meter but instead had the current turn on an LED (red) when the lim= it=20 was hit. 
 
One of the things that I had planned to do was=20 incorporate a manifold pressure input (as well as prop rpm) to automatica= lly=20 adjust to prop pitch to maintain rpm under various loading.  The har= dware=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;
 &nb= sp; =20 RPM_CC :=3D 5600;
    RPM_CR :=3D 5200;
  =  =20 RPM_DC :=3D 5500;
    //Put address of varible RPM_TO i= nto=20 Pointer variable
    PORTB.RB0 :=3D 1; //set to enter w= hile=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 o= r DC=20 from a menu and the prop was pitch was positioned/adjusted to maintain th= e=20 rpm.  Manifold pressure was also a factor.  Also it had directi= on=20 LEDs so you could select to manuall/electrically increase or decrease pit= ch=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 gon= e on to=20 completion, but alas despite the best efforts of a number of good folks i= t did=20 not.
 
Ed
 
Edward L. Anderson
Anderson Electronic Enterpr= ises=20 LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com
 
 
 
 

From: Chad 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 w= orks.=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 tu= rn it=20 one way, negative turns it the other, and while not moving there is no vo= ltage=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=20 properly inside the prop at full RPM would have been complicated/maybe=20 unreliable? They'd also be a pain to adjust.

Anyway, the motor dra= ws=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 m= eter=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. I= t'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 happen= s.=20 You don't "run it until it pops." You "run it until it's where you want i= t 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 ab= out=20 the shorted switch. That's pretty rare, and the breaker would deal with i= t=20 just fine. And I can't speak for anybody else, but every car I've ever ow= ned=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 Suba= ru,=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 an= d=20 also keep tripping a breaker when you manually reset that. Both devices h= ave=20 the same failure mode if it's the switch that's the problem. But you stil= l=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 des= igned=20 to fail critical flight gear in the case of improper control
manipul= ation=20 when they don't have to? Isn't this the classical and proper applicatio= n for=20 a polyfuse? Polyfuses are
used in power windows for this exact reaso= n.=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 aga= inst=20 the switch.
Why does the motor draw current after the pitch has been changed?<= /DIV>
 
Lynn E. Hanover 

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

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