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Throttle Servo

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caldwelljf(at)sbcglobal.n
Guest

Posted: Fri Apr 25, 2008 1:24 pm Post subject: Throttle Servo

I am building a CH-801 and am in need of a dual throttle setup so one canm fly from eithr side given there is a "Y" shaped stick in the center.

  

 I had in mind a "fly by wire" arrangement.  If I could connect a servo to the "throttle door", I could then conect a throttle quadrant with a "pot" connected to it and actuate the throttle from either side; Pilot with left hand and Co pilot with right hand..  Using a switch I could assign the servo to the Pilot or Copilot.

  

 Any ideas?

 

Jay F. Caldwell

Owner, Caldwell Systems Engineering (CSE), LLC

4181 Tamilynn Court

San Diego, CA 92122

Office email caldwell(at)mswin.net

Voice 858.453.4594

Facsimile 858.452.1560

Work 619.562.0885

Mobile 858.336.0394

Hanger 760-789-2557  

 [quote][b]

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frank.hinde(at)hp.com
Guest

Posted: Fri Apr 25, 2008 1:45 pm Post subject: Throttle Servo

No, No and...NO...



This is a really bad idea. This represents a single point of failure which is always a bad idea on a critical system on an airplane...Especially an electrical one



In other words if any one of half a dozen failures occurs you could very easily die...namely, a fuse blows, faulty wring, servo dies...etc



Don't do it!



Maybe if you have 2 servos and two electrically independant pots then maybe but really a cable is the way to go...two cables if you have two throttles

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Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Fri Apr 25, 2008 1:50 pm Post subject: Throttle Servo

Jay, I know of someone who is developing a "fly  by wire" throttle body using the Mazda "Fly by wire throttle body - Rx-8  auto".  He is installing it in his Rv-8. He produces electronic   devices for aircraft.  I have seen it in operation - not only is it  very neat, but it also opens up possibility of some automatic engine control  features such as:

  

 1. Setting throttle to maintain engine  rpm

 2. Setting throttle to maintain engine manifold  pressure

 3. Setting throttle to maintain a constant fuel  flow

 etc.

  

 Contact me off-line if interested.

  

 Ed Anderson

  

 Ed Anderson

Rv-6A N494BW Rotary  Powered

Matthews, NC

eanderson(at)carolina.rr.com (eanderson(at)carolina.rr.com)

http://www.andersonee.com

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.dmack.net/mazda/index.html

 [quote]   ---

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_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

BobsV35B(at)aol.com
Guest

Posted: Fri Apr 25, 2008 2:09 pm Post subject: Throttle Servo

Good Afternoon Jay,

  

 I know this is an electrical list, but I think I would look at a Stearman  or other tandem cockpit airplane for guidance. 

  

 Even the J-3 Cub uses two throttles that move at the same time.   

  

 I think a mechanical system would be better. As a flight instructor, I also  like the idea of both controls moving when either one is actuated. One of the  things I don't like about the Air Bus is that you can't see what movements the  copilot is making on his/her side stick.

  

 I would think a mechanical setup would be easy to arrange, very economical,  and very reliable.

  

 Happy  Skies,



Old Bob

AKA

Bob Siegfried

Ancient Aviator

628 West  86th Street

Downers Grove, IL 60516

630 985-8502 

Stearman  N3977A

Brookeridge Air Park LL22

  

  In a message dated 4/25/2008 4:26:45 P.M. Central Daylight Time,  caldwelljf(at)sbcglobal.net writes:

  	  Quote: 	
		     I am building a CH-801 and am in need of a dual throttle setup so one can    fly from either side given there is a "Y" shaped stick in the    center.

    

   I had in mind a "fly by wire" arrangement.  If I could connect a    servo to the "throttle door", I could then connect a throttle quadrant with a    "pot" connected to it and actuate the throttle from either side; Pilot with    left hand and Co pilot with right hand..  Using a switch I could assign    the servo to the Pilot or Copilot.

    

   Any ideas?

 

Jay F.  Caldwell

	






Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos.

  [quote][b]

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frank.hinde(at)hp.com
Guest

Posted: Fri Apr 25, 2008 2:09 pm Post subject: Throttle Servo

Buy a constant speed prop!...Does all of this, more  efficiently (cus closing a throttle is a poor thing to do efficiency wise;..at  least at cruise) and its safer!

  

 One dirty pot and does you throttle go to idle?..Like  everything else all the fialure modes have to be understood.

  

 Frank



   From:  owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Ed  Anderson

Sent: Friday, April 25, 2008 2:46 PM

To:  aeroelectric-list(at)matronics.com

Subject: Re: AeroElectric-List:  Throttle Servo

 

 Jay, I know of someone who is developing a "fly  by wire" throttle body using the Mazda "Fly by wire throttle body - Rx-8  auto".  He is installing it in his Rv-8. He produces electronic   devices for aircraft.  I have seen it in operation - not only is it  very neat, but it also opens up possibility of some automatic engine control  features such as:

  

 1. Setting throttle to maintain engine  rpm

 2. Setting throttle to maintain engine manifold  pressure

 3. Setting throttle to maintain a constant fuel  flow

 etc.

  

 Contact me off-line if interested.

  

 Ed Anderson

  

 Ed Anderson

Rv-6A N494BW Rotary  Powered

Matthews, NC

eanderson(at)carolina.rr.com (eanderson(at)carolina.rr.com)

http://www.andersonee.com

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.dmack.net/mazda/index.html

 [quote]   ---

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mprather(at)spro.net
Guest

Posted: Fri Apr 25, 2008 3:25 pm Post subject: Throttle Servo

I know fly by wire makes everybody's hair stand up..  But I don't think

it's a terrible idea.  It would definitely require careful design and

implementation, but it could certainly be lighter and lower maintenance.



A few thoughts:



The control doesn't have to use a pot to generate signal.  An optical

position sensor seems feasible to me.  Or maybe a capacitive sensor.



The throttle levers could be motorized - effectively linking them together

- and provide feedback.  Not trivial, but possible.  A switch on the panel

would select which throttle handle was in charge, and which was just

indicating.



It could also be relatively easy to make the throttle body spring loaded

to WOT - achieving this position if power is lost/cut to the

controller/positioner.  A reasonable fail safe not unlike our existing

all-mechanic systems.



At would also be reasonably easy to put a mechanical echo throttle control

in the middle of the panel.  It would just ride along with what the

whatever position the throttle body was in (indicating) - unless you had a

control failure.  If the power to the system is cut, this is now the

control.  The ergonomics might be less than optimal, but it would allow

you to control the engine output.



All that said, it should be fairly easy to make an all mechanical setup. 

You could have a torque tube attached to the panel which translates the

throttle movement from one side to the other.  I kind of wonder about how

to make a friction lock work, but I'm sure it's possible.



If it were mine, I'd use a mechanical throttle on each side of the panel

but only one mixture (and prop) control - in the middle.

Regards,



Matt-

[quote] Buy a constant speed prop!...Does all of this, more efficiently (cus

 closing a throttle is a poor thing to do efficiency wise;...at least at

 cruise) and its safer!



 One dirty pot and does you throttle go to idle?..Like everything else all

 the fialure modes have to be understood.



 Frank



 ________________________________

 From: owner-aeroelectric-list-server(at)matronics.com

 [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Ed

 Anderson

 Sent: Friday, April 25, 2008 2:46 PM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: Throttle Servo



 Jay, I know of someone who is developing a "fly by wire" throttle body

 using the Mazda "Fly by wire throttle body - Rx-8 auto".  He is installing

 it in his Rv-8. He produces electronic  devices for aircraft.  I have seen

 it in operation - not only is it very neat, but it also opens up

 possibility of some automatic engine control features such as:



 1. Setting throttle to maintain engine rpm

 2. Setting throttle to maintain engine manifold pressure

 3. Setting throttle to maintain a constant fuel flow

 etc.



 Contact me off-line if interested.



 Ed Anderson



 Ed Anderson

 Rv-6A N494BW Rotary Powered

 Matthews, NC

 eanderson(at)carolina.rr.com<mailto:eanderson(at)carolina.rr.com>

 http://www.andersonee.com

 http://members.cox.net/rogersda/rotary/configs.htm#N494BW

 http://www.dmack.net/mazda/index.html

 ---

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Ed Anderson

Joined: 10 Jan 2006
Posts: 475

Posted: Fri Apr 25, 2008 4:14 pm Post subject: Throttle Servo

No doubt, a CS is more efficient, but also very  much more costly to acquire and properly maintain and props also fail -  (single point of failure? - unless you fly a twin).  A case could be make  that a fixed pitch prop is inherently more safe than a CS.  But, many (if  not most of us) would love to have a light weight (inexpensive) CS hung off our  nose (or tail as the case may be) even if less reliable.

  

 Anything mechanical or electronic  can and  will eventually fail (cables also break, bind or become detached).  Check  on the FAA accident list and observe how frequently an engine (or some related  component) is cited in the accident report.  Yet, we have been producing  and flying with essentially the same engine design for 60 years. 

  

 One could point out that by virtue of our  decision to be airborne (without naturally bestowed wings) we are increasing our  risk, yet, we take that risk.  Because, most of us believe (correctly or  not) that we mitigate that risk in our favor by our awareness, knowledge,  skills and understanding. 

  

  Every new approach in aviation has  certainly carried risks - frequently not fully appreciate at the beginning-  but techniques  and technology has generally overcome the faults to  give us increased reliability and safety. Space flight relies almost  exclusively on electronic controls vice mechanical ones - simply because it has  been repeatedly shown that properly designed electronic systems fail less often  than mechanical ones and are generally much easier to build redundancy/safe  guards into in event they should fail.   

  

 Thinking about Jimmy Dolittle and the other  participants in  first "instrument" flights come to mind. Hydraulic brakes  replacing cables, GPS, autopilots, heated pitot tubes, electric gyros, electric  fuel pumps, etc., are just a few of what once were "new " technology now  commonly accepted.

  

 Fortunately, we have sufficient difference of  opinions and views on this list that each side gets presented and the  inquiring mind can make a (hopefully) informed decision.  So I also urge  caution being undertaken when trying a "different" approach - make certain you  understand the risks as well as your ability to assess and mitigate them - you  may fool yourself, but not the laws of physics.  That said, if no one tried  anything new - there would be no advancement in aviation.

  

 But, to answer your specific question about  possible pot malfunction - while environmentally sealed pots are readily  available, if I were to design a fly-by-wire throttle,  I would  probably go with a digital pot which has no physical parts to wear and which can  have values stored in nonvolatile memory to handle such things as lost of control signal,  etc . 

  

 Excerpt  from a producer of such  devices:

  

 Digital potentiometers are far more reliable than mechanical  potentiometers. Digital pots can easily guarantee 50,000 writing cycles, while  the mechanical parts rate only a few thousand, and sometimes only a few  hundred.  

 http://www.maxim-ic.com/appnotes.cfm/appnote_number/3417/

  

  

 Best Regards

  

 Ed

  

  

 - -----  Original Message ----- 

 [quote]   From:    Hinde, Frank    George (Corvallis) (frank.hinde(at)hp.com) 

   To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)    

   Sent: Friday, April 25, 2008 6:03  PM

   Subject: RE: Throttle    Servo

   



   Buy a constant speed prop!...Does all of this, more    efficiently (cus closing a throttle is a poor thing to do efficiency    wise;...at least at cruise) and its safer!

    

   One dirty pot and does you throttle go to idle?..Like    everything else all the fialure modes have to be    understood.

    

   Frank



         From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)    [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Ed    Anderson

Sent: Friday, April 25, 2008 2:46 PM

To:    aeroelectric-list(at)matronics.com

Subject: Re: AeroElectric-List:    Throttle Servo

   

   Jay, I know of someone who is developing a "fly    by wire" throttle body using the Mazda "Fly by wire throttle body - Rx-8    auto".  He is installing it in his Rv-8. He produces electronic     devices for aircraft.  I have seen it in operation - not only is it    very neat, but it also opens up possibility of some automatic engine control    features such as:

    

   1. Setting throttle to maintain engine    rpm

   2. Setting throttle to maintain engine manifold    pressure

   3. Setting throttle to maintain a constant fuel    flow

   etc.

    

   Contact me off-line if interested.

    

   Ed Anderson

    

   Ed Anderson

Rv-6A N494BW Rotary    Powered

Matthews, NC

eanderson(at)carolina.rr.com (eanderson(at)carolina.rr.com)

http://www.andersonee.com

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.dmack.net/mazda/index.html

   [quote]     ---

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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_________________
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com

jindoguy(at)gmail.com
Guest

Posted: Fri Apr 25, 2008 4:25 pm Post subject: Throttle Servo

I won't comment either way on the safety of a fly by wire throttle, but I think Ed is right about the possibilities it presents. The unit in my Toyota truck is both very reliable and the cruise control is eerily accurate and easy to adjust upward or downward as needed. Why reinvent the wheel when you could snag everything out of a wrecking yard?

On Fri, Apr 25, 2008 at 6:19 PM, Matt Prather <mprather(at)spro.net (mprather(at)spro.net)> wrote:

[quote] --> AeroElectric-List message posted by: "Matt Prather" <mprather(at)spro.net (mprather(at)spro.net)>

 I know fly by wire makes everybody's hair stand up..  But I don't think

 it's a terrible idea.  It would definitely require careful design and

 implementation, but it could certainly be lighter and lower maintenance.

 A few thoughts:

 The control doesn't have to use a pot to generate signal.  An optical

 position sensor seems feasible to me.  Or maybe a capacitive sensor.

 The throttle levers could be motorized - effectively linking them together

 - and provide feedback.  Not trivial, but possible.  A switch on the panel

 would select which throttle handle was in charge, and which was just

 indicating.

 It could also be relatively easy to make the throttle body spring loaded

 to WOT - achieving this position if power is lost/cut to the

 controller/positioner.  A reasonable fail safe not unlike our existing

 all-mechanic systems.

 At would also be reasonably easy to put a mechanical echo throttle control

 in the middle of the panel.  It would just ride along with what the

 whatever position the throttle body was in (indicating) - unless you had a

 control failure.  If the power to the system is cut, this is now the

 control.  The ergonomics might be less than optimal, but it would allow

 you to control the engine output.

 All that said, it should be fairly easy to make an all mechanical setup.

 You could have a torque tube attached to the panel which translates the

 throttle movement from one side to the other.  I kind of wonder about how

 to make a friction lock work, but I'm sure it's possible.

 If it were mine, I'd use a mechanical throttle on each side of the panel

 but only one mixture (and prop) control - in the middle.

 Regards,

 Matt-

 > Buy a constant speed prop!...Does all of this, more efficiently (cus

 > closing a throttle is a poor thing to do efficiency wise;...at least at

 > cruise) and its safer!

 >

 > One dirty pot and does you throttle go to idle?..Like everything else all

 > the fialure modes have to be understood.

 >

 > Frank

 >

 > ________________________________

 > From: owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)

 > [mailto:owner-aeroelectric-list-server(at)matronics.com (owner-aeroelectric-list-server(at)matronics.com)] On Behalf Of Ed

 > Anderson

 > Sent: Friday, April 25, 2008 2:46 PM

 > To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)

 > Subject: Re: Throttle Servo

 >

 > Jay, I know of someone who is developing a "fly by wire" throttle body

 > using the Mazda "Fly by wire throttle body - Rx-8 auto".  He is installing

 > it in his Rv-8. He produces electronic  devices for aircraft.  I have seen

 > it in operation - not only is it very neat, but it also opens up

 > possibility of some automatic engine control features such as:

 >

 > 1. Setting throttle to maintain engine rpm

 > 2. Setting throttle to maintain engine manifold pressure

 > 3. Setting throttle to maintain a constant fuel flow

 > etc.

 >

 > Contact me off-line if interested.

 >

 > Ed Anderson

 >

 > Ed Anderson

 > Rv-6A N494BW Rotary Powered

 > Matthews, NC

 	  Quote: 	
		   eanderson(at)carolina.rr.com (eanderson(at)carolina.rr.com)<mailto:eanderson(at)carolina.rr.com (eanderson(at)carolina.rr.com)>

 > http://www.andersonee.com

 > http://members.cox.net/rogersda/rotary/configs.htm#N494BW

 > http://www.dmack.net/mazda/index.html

 > ---

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jmcburney(at)pobox.com
Guest

Posted: Sat Apr 26, 2008 8:09 am Post subject: Throttle Servo

Hi, Jay (and List),



The Zenith demo 801 has dual throttle controls.  They KISSed the problem:

ran both cables to the carb, connected both to the throttle lever.  It works

well, but you can't use a vernier throttle.  Zenith used friction-lock

throttles, took the friction bushing out of the secondary (right-seat)

control.  There are several ideas in the Matronics Zenith list archives that

have been done, mostly on 601s.  Check it out.



Blue skies and tailwinds



Jim

CH-801

DeltaHawk diesel

Augusta GA

90% done, 90% left

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