X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [201.225.225.168] (HELO cwpanama.net) by logan.com (CommuniGate Pro SMTP 5.0.7f) with ESMTP id 950459 for flyrotary@lancaironline.net; Mon, 23 Jan 2006 11:32:43 -0500 Received-SPF: none receiver=logan.com; client-ip=201.225.225.168; envelope-from=rijakits@cwpanama.net Received: from [201.224.93.110] (HELO usuarioq3efog0) by frontend2.cwpanama.net (CommuniGate Pro SMTP 4.2.10) with SMTP id 57270093 for flyrotary@lancaironline.net; Mon, 23 Jan 2006 11:42:40 -0500 Message-ID: <002201c6203a$6b91ff40$6e5de0c9@usuarioq3efog0> From: "rijakits" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Prop controller RPM and Motor Limits - Automatic props Date: Mon, 23 Jan 2006 11:31:10 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001E_01C62010.827921E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_001E_01C62010.827921E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit MessageHi Ed, thanks for the details! So far I get it, but Mark seems also to measure "performance" (injector-pulse width), so I guess there would be a "best performance"- mode. However to really be able to program max-performance one would also need some kind of airspeed indication. Did anyone ever check on the Atomatic AVIA props? They work hydraulically, but seem to be selfcontained - a little ring wit vanes in front of the prop, adjusts the blade pitch according to speed and rpm. No idea about price and suitability.... ED, get back on the project!! Only 10% to go!! The market has space for some competition!! Besides you need something to do! How is the new hangar goin'? Thomas J. ----- Original Message ----- From: Ed Anderson To: Rotary motors in aircraft Sent: Monday, January 23, 2006 10:45 AM Subject: [FlyRotary] Prop controller RPM and Motor Limits was Re: Injector pulseing ? Tracy ? Hi Thomas, There at two design considerations that need attention when designing a controller for an electric pitch prop. One is determining prop rpm and the second is to determine when the pitch motor has reached its limits of travel. Prop RPM? When I decided to design an electric prop automatic pitch controller, I ran into the same design considerations. You need engine/prop rpm from some source. I decided to use an IR sensor reading a tape on the prop (to read its rpm directly) since I did not know what rpm sources might exist on different automobile engine conversions as well as different gear ratios which would ,of course, affect relationship between engine and prop speed. However, there are many ways to approach that need. I currently derive RPM form my EFI Monitor from measuring the interval between injections (once per e shaft rev). I suspect that Mark is taking a similar approach to get rpm for his controller. My controller was designed to maintain a certain prop rpm by sensing the prop rpm and automatically varying the pitch to maintain that rpm within a small window (to prevent rpm hunting). So if Power was increased the prop would automatically increase pitch to absorb the power and keep the rpm within the window and vice versa when power was reduced. I also had three "pre-programmed" rpms for Take off, Climb and Cruise that you could set by the push of a button. You could also manual establish your target rpm. I had the design 90% completed when the prop project went away so never finished it. Pitch Motor Limits? I think the second problem, as you mentioned, is determining the pitch motor travel limits to which I do not believe rpm is a crucial factor. You could install limit switches with the risk of added complexity and weight or you can devise a method to determine and warn when the limits are approached. I used a current sensing circuit (which you could adjust for different current levels) to light an LED. The more current the motor drew the brighter the LED glowed. So when the motor approached its stall limit and current increased dramatically over the running current, the LED would start to glow and the further you ran the motor to the limit the brighter it would glow. The operator must take the corrective action - although I already had a design in the conceptual stage to reverse the motor when the current exceeded a set amount. Then I decided that I did not want some computer making that decision {:>) Hope this might clarify some of the discussion Ed ----- Original Message ----- From: rijakits To: Rotary motors in aircraft Sent: Monday, January 23, 2006 9:46 AM Subject: [FlyRotary] Re: Injector pulseing ? Tracy ? Question. Why does he ( Mark B.) need the injector pulses? Unless he wants to have an automatic-best-performance feature, a simple rpm reading from the crank will do fine. a) Electronics will increase pitch when power is increased to maintain rpm in C/S mode. b) Pilot will change pitch in a variable pitch mode. AFAIU the problem is to find the exact endpoints of pitch travel. How does knowing the injector pulse width help with that? It will tell him how much power is produced in combination with an rpm input, but does he also measure airspeed? Not bitching, just trying to get the idea!! Thomas J. From: Russell Duffy To: Rotary motors in aircraft Sent: Monday, January 23, 2006 8:55 AM Subject: [FlyRotary] Re: Injector pulseing ? Tracy ? And how would Mark Burton's constant speed controller react if the EC2 was switched to injector disable mode. Depending on how it was wired, it might suddenly sense zero power or 2X power. Just thinking out loud. Good point Dean. If he only senses pulses to one injector, then it would have to be the primary, which is always active, unless you turn it off via the disable switch. He may not realize we have the ability to do that, so it would be worth telling him about it. Cheers, Rusty ------=_NextPart_000_001E_01C62010.827921E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Hi Ed,
 
thanks for the details!
So far I get it, but Mark seems also to measure=20 "performance" (injector-pulse width), so I guess there would be a "best=20 performance"- mode. However to really be able to program max-performance = one=20 would also need some kind of airspeed indication.
 
Did anyone ever check on the Atomatic AVIA=20 props?
They work hydraulically, but seem to be = selfcontained - a=20 little ring wit vanes in front of the prop, adjusts the blade pitch = according to=20 speed and rpm. No idea about price and suitability....
 
ED, get back on the project!! Only 10% to go!! = The market=20 has space for some competition!!
Besides you need something to do! How is the new = hangar=20 goin'?
 
Thomas J.
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Monday, January 23, 2006 = 10:45=20 AM
Subject: [FlyRotary] Prop = controller RPM=20 and Motor Limits was Re: Injector pulseing ? Tracy ?

Hi Thomas,
 
There at two design considerations that need = attention=20 when designing a controller for an electric pitch prop.  One is=20 determining prop rpm and the second is to determine when the pitch = motor has=20 reached its limits of travel.
 
Prop RPM?
 
When I decided to design an electric prop = automatic=20 pitch controller, I ran into the same design considerations.  You = need=20 engine/prop rpm from some source.  I decided to use an IR sensor = reading=20 a tape on the prop (to read its rpm directly) since I did not know = what rpm=20 sources might exist on different automobile engine conversions as well = as=20 different gear ratios which would ,of course, affect relationship = between=20 engine and prop speed.
 
However, there are many ways to approach that=20 need.  I currently derive RPM form my EFI Monitor from measuring = the=20 interval between injections (once per e shaft rev).  I suspect = that Mark=20 is taking a similar approach to get rpm for his = controller.
 
My controller was designed to maintain a = certain prop=20 rpm by sensing the prop rpm and automatically varying the pitch to = maintain=20 that rpm within a small window (to prevent rpm hunting).  So if = Power was=20 increased the prop would automatically increase pitch to absorb the = power and=20 keep the rpm within the window and vice versa when power was=20 reduced.
 
I also had three "pre-programmed" rpms for = Take off,=20 Climb and Cruise that you could set by the push of a button.  You = could=20 also manual establish your target rpm.
 
I had the design 90% completed when the prop = project=20 went away so never finished it.
 
Pitch Motor Limits?
 
I think the second problem, as you mentioned, = is=20 determining the pitch motor travel limits to which I do not believe = rpm is a=20 crucial factor.  You could install limit switches with the risk = of added=20 complexity  and weight or you can devise a method to determine = and warn=20 when the limits are approached. 
 
 I used a current sensing circuit (which = you could=20 adjust for different current levels) to light an LED.  The more = current=20 the motor drew  the brighter the LED glowed.  So when the = motor=20 approached its stall limit and current increased dramatically over the = running=20 current, the LED would start to glow and the further you ran the motor = to the=20 limit the brighter it would glow.  The operator must take the = corrective=20 action - although I already had a design in the conceptual stage to = reverse=20 the motor when the current exceeded a set amount.  Then I decided = that I=20 did not want some computer making that decision {:>)
 
Hope this might clarify some of the=20 discussion
 
 
Ed
----- Original Message -----
From:=20 rijakits
To: Rotary motors in = aircraft=20
Sent: Monday, January 23, = 2006 9:46=20 AM
Subject: [FlyRotary] Re: = Injector=20 pulseing ? Tracy ?

Question.
 
Why does he ( Mark B.) need the injector=20 pulses?
Unless he wants to have an = automatic-best-performance=20 feature, a simple rpm reading from the crank will do = fine.
a) Electronics will increase pitch when = power is=20 increased to maintain rpm in C/S mode.
b) Pilot will change pitch in a variable = pitch=20 mode.
 
AFAIU the problem is to find the exact = endpoints of=20 pitch travel. How does knowing the injector pulse width help with=20 that?
It will tell him how much power is produced = in=20 combination with an rpm input, but does he also measure=20 airspeed?
 
Not bitching, just trying to get the=20 idea!!
 
Thomas J.
 
 
To: Rotary motors in = aircraft=20
Sent: Monday, January 23, = 2006 8:55=20 AM
Subject: [FlyRotary] Re: = Injector=20 pulseing ? Tracy ?

And how would Mark
Burton's constant speed = controller=20 react if the EC2 was switched to injector
disable mode.  = Depending=20 on how it was wired, it might suddenly sense zero
power or 2X=20 power.  Just thinking out loud.

Good point=20 Dean.  If he only senses pulses to one injector, then it = would have=20 to be the primary, which is always active, unless you turn it off = via the=20 disable switch.  He may not realize we have the = ability to do=20 that, so it would be worth telling him about it. =20
 
Cheers,
Rusty=20
 
 
=


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