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user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Fri Jan 14, 2011 6:56 am Post subject: model airplane servo

I want to install electric aileron trim.  I could buy a Ray Allen servo and control its speed with PWM.  I was wondering if there are any other options that might be lighter weight or smaller.  Has anyone had experience with linear actuators or model airplane R/C servos?  Do the RC model servos hold their position when power is removed?  The ideal 12vdc servo would be slow moving and would be operated by a switch without electronic controls.  It should also have built-in limit switches and a position feedback pot.  Maybe the Ray Allen is the best.

Thanks, Joe

_________________
Joe Gores

mdnanwelch7(at)hotmail.co
Guest

Posted: Fri Jan 14, 2011 7:32 am Post subject: model airplane servo

>Has anyone had experience with linear actuators or model airplane R/C servos? 

 > Joe Gores

  

 Hi Joe,

  

   A couple of years ago, I considered doing the same thing you are referring to, 

 using an RC model servo for a full sized airplane.  I checked them out, there are a 

 LOT of them, and they are usually graded by how much "pull or push" they can 

 generate.   If my memory is correct, I think I can remember something like "32 grams" as 

 the biggest version, or at least a 'near' biggest version..  I did some more looking 

 around, but I don't remember if I ever found out what the RC Allen servo's rating was.,

 ...but after I weighed the option of trying experiment (yet again!!), I decided to go with the 

 RAC servo, and frankly, I'm glad I did!

  

   It was made precisely for my intended use, so no experimentation necessary, and they

 even come with little clevis forks, and matching pins, and the kind of stuff you'd

 expect to find on such a devise.

  

   I suppose if a guy looked long enough, he may be able to find a servo that rates 

 higher than 32 gms, but even still, I'd think he'd still be better off with the RAC servo.

 That's not to say it can't be done, but I think you may be installing something that MAY

 not be up to the task.

  

 Mike Welch

 



 		 	   		    [quote][b]

Bob McC

Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON

Posted: Fri Jan 14, 2011 8:24 am Post subject: model airplane servo

Joe;



It does have all of those features and that is specifically its purpose, so

it would be a logical choice. Any of the other options you mention would

likely require adaptation and you would have to do the experimentation and

reliability research already done for you by Ray Allen. In my humble opinion

I would suggest you've reached the correct conclusion when you said "Maybe

the Ray Allen is the best".



Bob McC

_________________
Bob McC
Falco #908
(just starting)

wschertz(at)comcast.net
Guest

Posted: Fri Jan 14, 2011 8:47 am Post subject: model airplane servo

Check out http://www.periheliondesign.com/moreproducts.htm for a controller 

for Futaba, etc servos. Also has trim wheels, etc.



Bill Schertz

KIS Cruiser #4045

N343BS



--

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jan 14, 2011 9:02 am Post subject: model airplane servo

At 09:56 AM 1/14/2011, you wrote:

 	  Quote: 	
		  



I want to install electric aileron trim.  I could buy a Ray Allen 

servo and control its speed with PWM.  I was wondering if there are 

any other options that might be lighter weight or smaller.  Has 

anyone had experience with linear actuators or model airplane R/C 

servos?  Do the RC model servos hold their position when power is 

removed?  The ideal 12vdc servo would be slow moving and would be 

operated by a switch without electronic controls.  It should also 

have built-in limit switches and a position feedback pot.  Maybe the 

Ray Allen is the best.


	


   I have a skunk-werks bin with about a dozen

   RC actuators that were used in various remote

   control situations over the years.



   These are short throw (short rotation) devices

   with output shafts designed to move control

   surfaces with a bellcrank. I have some about the

   size of a postage stamp that cost about $10 up

   to puppies like this:



http://www.gpdealera.com/cgi-bin/wgainf100p.pgm?I=FUTM0216



   for about $100.



   They're spur-geared and do not LOCK position

   when turned off. Linear actuators like the

   RC Allen will not back-drive when powered down.



   Further, they're a bit user unfriendly as stock

   actuators. They run on 4.5 to 7.0 volts. The

   position command signal is a variable duty

   cycle pulse. Easy to control out of a microprocessor

   (or r/c receiver) not to easy from the pilot's

   seat.



   I've used these as rudimentary motor-gearbox

   assemblies. You can remove the stops, pot

   and electronics. The rudimentary assembly

   can then drive a lead-screw to provide a LOT

   of force over long distances.



   I guess the short answer to your question is

   no. But they DO offer some interesting opportunities

   for a variety of remote control tasks if

   you've got the interest and energy to stroke 'em.

   Bob . . .

retasker(at)optonline.net
Guest

Posted: Fri Jan 14, 2011 9:25 am Post subject: model airplane servo

While the RC servos do hold their position with power off, it is not 

quite locked.  You can move them with some force.  Whether the ailerons 

would apply enough force to do so is a question unanswered.



I would suggest you stick with the proven solution even though it is 

somewhat pricey compared to an RC servo.  You can change the speed with 

PWM or if you want a true servo based on the Ray Allen design, see the 

same page listed below for an add-on..



Dick Tasker



Bill Schertz wrote:

[quote] 

 <wschertz(at)comcast.net>



 Check out http://www.periheliondesign.com/moreproducts.htm for a 

 controller for Futaba, etc servos. Also has trim wheels, etc.



 Bill Schertz

 KIS Cruiser #4045

 N343BS



 --

sprocket(at)vx-aviation.c
Guest

Posted: Fri Jan 14, 2011 10:06 am Post subject: model airplane servo

I think these servos should be considered:



http://store.firgelli.com



I haven't used them myself, but they seem appropriate to the application. 

They are located a few miles from me, so one day I should go visit and give 

a PIREP.



Vern Little



--

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jan 14, 2011 11:11 am Post subject: model airplane servo

At 01:03 PM 1/14/2011, you wrote:

 	  Quote: 	
		  

<sprocket(at)vx-aviation.com>



I think these servos should be considered:



http://store.firgelli.com



I haven't used them myself, but they seem appropriate to the 

application. They are located a few miles from me, so one day I 

should go visit and give a PIREP.


	


    These look interesting . . . especially since

    they're offered with built in servo electronics

    to integrate into a variety of voltages and

    control protocols (including R/C variable

    pulse width). They DO report a back-driving

    force value but it's probably very high

    compared to working loads. It would be

    interesting to know what lead-screw

    configuration they are using.



   Bob . . .

ceengland(at)bellsouth.ne
Guest

Posted: Fri Jan 14, 2011 3:25 pm Post subject: model airplane servo

On 1/14/2011 8:56 AM, user9253 wrote:

 	  Quote: 	
		   



 I want to install electric aileron trim.  I could buy a Ray Allen servo and control its speed with PWM.  I was wondering if there are any other options that might be lighter weight or smaller.  Has anyone had experience with linear actuators or model airplane R/C servos?  Do the RC model servos hold their position when power is removed?  The ideal 12vdc servo would be slow moving and would be operated by a switch without electronic controls.  It should also have built-in limit switches and a position feedback pot.  Maybe the Ray Allen is the best.

 Thanks, Joe



 --------

 Joe Gores

Hi Joe,
	




My 1st homebuilt was a (purchased) Thorp T-18 that had a homebuilt 

autopilot (wing leveler) and aileron trim system using a trim tab on one 

aileron. It used a standard model a/c servo, just like what you're 

probably thinking about. The autopilot used an ingenious 

pneumatic/thermal rate sensor as its heart. A stream of air moving 

between two thermal sensors made up the rate sensor. The system had roll 

trim that used a generic potentiometer to drive the servo controller. 

The autopilot section wasn't functional when I bought the plane (it had 

been stored for about 5 years before I bought it), but the trim feature 

worked just fine for the short time I owned the plane. Failure modes 

were never explored by me, because it just worked.



If you're handy with electronics and the application of tools to small 

projects, I can't see why you can't add a worm drive to the servo if it 

would make you feel more comfortable. Or, you could just do flutter 

testing on a trim tab type system with power removed from the servo 

(which you'll need to do anyway, if you add any kind of trim tab to the 

aileron). It's not likely that you would have any luck mounting the trim 

tab on the wing tip itself (it's been tried by others; there just isn't 

enough aerodynamic authority unless the tab is almost as big as the 

aileron).



BTW, a neighbor has a homebuilt that has the same autopilot design as my 

Thorp, but with the addition of a homebuilt magnetic heading source that 

allowed the autopilot to actually follow a magnetic heading.



Compared to the 'oldtimers', we young 50-60 year-old 'experimenters' are 

just delivery guys for Ikea. 



Charlie

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jan 14, 2011 4:03 pm Post subject: model airplane servo

 	  Quote: 	
		  ust isn't enough aerodynamic authority unless the tab is almost as 

big as the aileron).



BTW, a neighbor has a homebuilt that has the same autopilot design 

as my Thorp, but with the addition of a homebuilt magnetic heading 

source that allowed the autopilot to actually follow a magnetic heading.



Compared to the 'oldtimers', we young 50-60 year-old 'experimenters' 

are just delivery guys for Ikea. 


	


  Charlie,



   The system you've described sounds like a DIY system designed

   conceived by a NASA engineer named Doug Garner. I think it was

   written up in several issues of Sport Aviation circa 1980.

   Doug developed a home brew rate sensor based on a small speaker

   huffing on a venturi to produce a steady stream of air between

   two de-bulbed lamps used as hot-wire anemometers. He also crafted

   a flux gate compass for magnetic heading hold. Very clever stuff.

   I met him briefly at OSH about 1986 or so. The autopilot brains

   was an 8-bit micro-controller.



   Today we have solid state rate sensors, silicon magnetometers

   and GPS serial data to effect VERY precise course hold. Of

   course, the R/C servos have become still more robust and many

   feature all metal gear trains. I think I've got copies of

   his articles buried somewhere. I ought to scan them and

   put them up on the website as historical data.



   Bob . . .

ceengland(at)bellsouth.ne
Guest

Posted: Fri Jan 14, 2011 5:32 pm Post subject: model airplane servo

On 1/14/2011 4:59 PM, Robert L. Nuckolls, III wrote:

 	  Quote: 	

 <nuckolls.bob(at)aeroelectric.com>

> ust isn't enough aerodynamic authority unless the tab is almost as 

> big as the aileron).

>

> BTW, a neighbor has a homebuilt that has the same autopilot design as 

> my Thorp, but with the addition of a homebuilt magnetic heading 

> source that allowed the autopilot to actually follow a magnetic heading.

>

> Compared to the 'oldtimers', we young 50-60 year-old 'experimenters' 

> are just delivery guys for Ikea. 

  Charlie,

   The system you've described sounds like a DIY system designed

   conceived by a NASA engineer named Doug Garner. I think it was

   written up in several issues of Sport Aviation circa 1980.

   Doug developed a home brew rate sensor based on a small speaker

   huffing on a venturi to produce a steady stream of air between

   two de-bulbed lamps used as hot-wire anemometers. He also crafted

   a flux gate compass for magnetic heading hold. Very clever stuff.

   I met him briefly at OSH about 1986 or so. The autopilot brains

   was an 8-bit micro-controller.

   Today we have solid state rate sensors, silicon magnetometers

   and GPS serial data to effect VERY precise course hold. Of

   course, the R/C servos have become still more robust and many

   feature all metal gear trains. I think I've got copies of

   his articles buried somewhere. I ought to scan them and

   put them up on the website as historical data.

   Bob . . .

I think you're right about the source; I have read the articles. I have 

the schematics & wiring diagrams somewhere; if I stumble upon them I'll 

scan & forward. I even have the 'heart' of the hardware somewhere; I'll 

try to send some pics of that, too. IIRC, the rate sensor was built into 

a coffee can.   I'm certainly not advocating a return that 

technology; I was just trying to point out how little real experimenting 

we really do these days.

Charlie

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Sat Jan 15, 2011 7:44 am Post subject: Re: model airplane servo

Thanks to Bob and others for the replies and suggestions.

 	  Quote: 	
		  It's not likely that you would have any luck mounting the trim

tab on the wing tip itself (it's been tried by others; there just isn't

enough aerodynamic authority unless the tab is almost as big as the

aileron). 	


That is exactly what I had planned to do.  Thanks for the warning, Charlie.  Sometimes I get obsessed with details and neglect to stand back and look at the feasibility of the whole project.  I do not want to add a trim tab to the ailerons because I am afraid of causing flutter.  So I had intended to mount a trim tab on the wing tip.  Since it has been tried by others without success, I could be wasting my time and money if installing wing tip trim tabs.

Joe

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jan 15, 2011 9:05 am Post subject: model airplane servo

 	  Quote: 	
		  > It's not likely that you would have any luck mounting the trim

 > tab on the wing tip itself (it's been tried by others; there just isn't

 > enough aerodynamic authority unless the tab is almost as big as the

 > aileron). 



 That is exactly what I had planned to do.  Thanks for the warning, Charlie.  Sometimes I get obsessed with details and neglect to stand back and look at the feasibility of the whole project.  I do not want to add a trim tab to the ailerons because I am afraid of causing flutter.  So I had intended to mount a trim tab on the wing tip.  Since it has been tried by others without success, I could be wasting my time and money if installing wing tip trim tabs. 	


   It's an easy experiment to explore. Use some speed tape

   to stick a fixed sheet metal tab on the trailing edge

   of the tip. Size it to some value you think might be

   tolerable from the perspective of appearance and practical

   implementation. Go fly and see how much trim authority

   you're having to offset in the stick.



   Keep in mind that you're wanting to trim out small

   operational variations in roll trim. This isn't

   an autopilot design project with a goal of exerting

   the same authority in roll as the pilot, you're

   wanting to offset relatively small trim offsets

   due to loading and fuel distribution.



   The Zodiac avoids aileron flutter issues by trimming

   with a separate mini-aileron.



 [img]cid:.0[/img]



 

   Other pictures of aileron trim tabs seem to illustrate

   relatively small mechanisms



 [img]cid:.1[/img]



 [img]cid:.2[/img]



    Also consider an actuator driven spring cartridge rigged

    to the aileron controls under the floor boards. This

    technique has been used by many designers with 

    success. You can develop your own design goals.



 

   Bob . . .

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jcorner(at)shaw.ca
Guest

Posted: Sat Jan 15, 2011 10:12 am Post subject: model airplane servo

I have been successfully using model aircraft servos for several years, first on a Kitfox 2 and more recently on a Model 5.



Initially started with rudder only trim, graduating to full three axis trim control using a microcontroller Motorola MC68HC08 to operate the servos.



This was expanded several years ago to include GPS route tracking.   More recently altitude hold.  This autopilot design is still being developed, and refined. 



For trim only the  R/C servo will tracks the potentiometer position,  and is constantly powered to maintain its position.



Satisfactory R/C servo controllers for trim only can cost less than $20, servos $40. and a power supply for 5-6  volts at 5 amps < $20.



I have found these servos to be quite durable with one servo on my Kitfox 2 (Hitec 805BB) lasting over 500 hrs flying, a similar servo on the 5 now has 150 + hours.



I could go on forever, but will wait to see if there is further interest.   Meanwhile I suspect there will be a few questions.



Jim  



On 2011-01-14, at 7:56 AM, user9253 wrote:



 	  Quote: 	
		   

 

 I want to install electric aileron trim.  I could buy a Ray Allen servo and control its speed with PWM.  I was wondering if there are any other options that might be lighter weight or smaller.  Has anyone had experience with linear actuators or model airplane R/C servos?  Do the RC model servos hold their position when power is removed?  The ideal 12vdc servo would be slow moving and would be operated by a switch without electronic controls.  It should also have built-in limit switches and a position feedback pot.  Maybe the Ray Allen is the best.

 Thanks, Joe

 

 --------

 Joe Gores

jdubner(at)yahoo.com
Guest

Posted: Sat Jan 15, 2011 2:37 pm Post subject: model airplane servo

Jim Corner wrote:



 	  Quote: 	
		   

 

 I have been successfully using model aircraft servos for several years ...

[snip]
	


 	  Quote: 	
		   I could go on forever, but will wait to see if there is further interest.   Meanwhile I suspect there will be a few questions.


	


Jim,



I'm happy to see someone (else) proving the naysayers wrong.  This has 

been a pet project of mine for almost as long as you and I've taken a 

similar approach using a different controller (ATmega8).  I'm even using 

a $18 servo to change the position of one of my landing lights for taxi.



Question, please: where have you found for a source of bellcrank, 

clevis, threaded rod and other hardware?  I'd like to find some 10-32 

but all the model airplane stuff I've found is pretty wimpy (4-40 or 

6-32 at best).  On my landing light the RC stuff is OK but I'd like an 

"aviation grade" mechanical coupling for the elevator and aileron trim 

on my RV.



--

Joe

Independence, OR

http://www.mail2600.com/position

http://www.mail2600.com/cgi-bin/webcam.cgi

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Sat Jan 15, 2011 3:00 pm Post subject: Re: model airplane servo

 	  Quote: 	
		  It's an easy experiment to explore. Use some speed tape

to stick a fixed sheet metal tab on the trailing edge

of the tip. Size it to some value you think might be

tolerable from the perspective of appearance and practical

implementation. Go fly and see how much trim authority

you're having to offset in the stick. 	


That is a very good idea, Bob.  I should have thought of that because I did the same thing on the rudder.  The runway is covered with snow, so I will have to wait before experimenting in the air.

Joe

_________________
Joe Gores

jcorner(at)shaw.ca
Guest

Posted: Sat Jan 15, 2011 5:43 pm Post subject: model airplane servo

Joe 



I'm using hardware designed for giant scale RC.  The bolts are 8-32 and the push rods are 6 gauge rods.  Your speeds are higher than mine, but remember that you require less deflection for the same result.  Also we are trimming aerodynamically balanced surfaces and the air load on the trim tabs are a lot less than most expect.  I have attached a photo of my flaperon servo installation.  It is very effective and can induce a very high roll rate.  



Jim





 



 	  Quote: 	
		   

 I'm happy to see someone (else) proving the naysayers wrong.  This has been a pet project of mine for almost as long as you and I've taken a similar approach using a different controller (ATmega8).  I'm even using a $18 servo to change the position of one of my landing lights for taxi.

 

 Question, please: where have you found for a source of bellcrank, clevis, threaded rod and other hardware?  I'd like to find some 10-32 but all the model airplane stuff I've found is pretty wimpy (4-40 or 6-32 at best).  On my landing light the RC stuff is OK but I'd like an "aviation grade" mechanical coupling for the elevator and aileron trim on my RV.

 

 --

 Joe

 Independence, OR

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Flydad57(at)neo.rr.com
Guest

Posted: Sat Jan 15, 2011 6:01 pm Post subject: model airplane servo

I am interested in the possibilities of using an R/C servo for the pitch 

trim on my TigerCub.  Any and ALL details very welcomed!



Thanks for any info.



Bob Taylor

TigerCub N657RT



--------------------------------------------------

From: "Jim Corner" <jcorner(at)shaw.ca>

Sent: Saturday, January 15, 2011 1:08 PM

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

Subject: Re: model airplane servo



 	  Quote: 	
		   



 I have been successfully using model aircraft servos for several years, 

 first on a Kitfox 2 and more recently on a Model 5.



 Initially started with rudder only trim, graduating to full three axis 

 trim control using a microcontroller Motorola MC68HC08 to operate the 

 servos.



 This was expanded several years ago to include GPS route tracking.   More 

 recently altitude hold.  This autopilot design is still being developed, 

 and refined.



 For trim only the  R/C servo will tracks the potentiometer position,  and 

 is constantly powered to maintain its position.



 Satisfactory R/C servo controllers for trim only can cost less than $20, 

 servos $40. and a power supply for 5-6  volts at 5 amps < $20.



 I have found these servos to be quite durable with one servo on my Kitfox 

 2 (Hitec 805BB) lasting over 500 hrs flying, a similar servo on the 5 now 

 has 150 + hours.



 I could go on forever, but will wait to see if there is further interest. 

 Meanwhile I suspect there will be a few questions.



 Jim



 On 2011-01-14, at 7:56 AM, user9253 wrote:



> 

> <fran4sew(at)banyanol.com>

>

> I want to install electric aileron trim.  I could buy a Ray Allen servo 

> and control its speed with PWM.  I was wondering if there are any other 

> options that might be lighter weight or smaller.  Has anyone had 

> experience with linear actuators or model airplane R/C servos?  Do the RC 

> model servos hold their position when power is removed?  The ideal 12vdc 

> servo would be slow moving and would be operated by a switch without 

> electronic controls.  It should also have built-in limit switches and a 

> position feedback pot.  Maybe the Ray Allen is the best.

> Thanks, Joe

>

> --------

> Joe Gores

>

email(at)jaredyates.com
Guest

Posted: Sat Jan 15, 2011 6:51 pm Post subject: model airplane servo

Look at the model helicopter suppliers too.  Like this one:



http://www.ronlund.com/mm5/merchant.mvc?Screen=PROD&Store_Code=RHPS&Product_Code=RCHCR&Category_Code=

 



[url=http://www.ronlund.com/mm5/merchant.mvc?Screen=PROD&Store_Code=RHPS&Product_Code=RCHCR&Category_Code=][/url]It's a hollow carbon fiber shaft with titanium threads and an aluminum ferrule.  For stiffness, weight, and strength, it might be something to consider.

 

On Sat, Jan 15, 2011 at 8:55 PM, Robert Taylor <Flydad57(at)neo.rr.com (Flydad57(at)neo.rr.com)> wrote:

[quote] --> AeroElectric-List message posted by: "Robert Taylor" <Flydad57(at)neo.rr.com (Flydad57(at)neo.rr.com)>

 

 I am interested in the possibilities of using an R/C servo for the pitch trim on my TigerCub.  Any and ALL details very welcomed!

 

 Thanks for any info.

 

 Bob Taylor

 TigerCub N657RT

 

 --------------------------------------------------

 From: "Jim Corner" <jcorner(at)shaw.ca (jcorner(at)shaw.ca)>

 Sent: Saturday, January 15, 2011 1:08 PM

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

 Subject: Re: model airplane servo

 

  	  Quote: 	
		   --> AeroElectric-List message posted by: Jim Corner <jcorner(at)shaw.ca (jcorner(at)shaw.ca)>

 



 I have been successfully using model aircraft servos for several years, first on a Kitfox 2 and more recently on a Model 5.

 

 Initially started with rudder only trim, graduating to full three axis trim control using a microcontroller Motorola MC68HC08 to operate the servos.

 

 This was expanded several years ago to include GPS route tracking.   More recently altitude hold.  This autopilot design is still being developed, and refined.

 

 For trim only the  R/C servo will tracks the potentiometer position,  and is constantly powered to maintain its position.

 

 Satisfactory R/C servo controllers for trim only can cost less than $20, servos $40. and a power supply for 5-6  volts at 5 amps < $20.

 

 I have found these servos to be quite durable with one servo on my Kitfox 2 (Hitec 805BB) lasting over 500 hrs flying, a similar servo on the 5 now has 150 + hours.

 

 I could go on forever, but will wait to see if there is further interest. Meanwhile I suspect there will be a few questions.

 

 Jim

 

 

 

 

 



 On 2011-01-14, at 7:56 AM, user9253 wrote:

 

  	  Quote: 	
		   --> AeroElectric-List message posted by: "user9253" <fran4sew(at)banyanol.com (fran4sew(at)banyanol.com)>

 

 I want to install electric aileron trim.  I could buy a Ray Allen servo and control its speed with PWM.  I was wondering if there are any other options that might be lighter weight or smaller.  Has anyone had experience with linear actuators or model airplane R/C servos?  Do the RC model servos hold their position when power is removed?  The ideal 12vdc servo would be slow moving and would be operated by a switch without electronic controls.  It should also have built-in limit switches and a position feedback pot.  Maybe the Ray Allen is the best.

  Thanks, Joe

 

 --------

 Joe Gores

 

 	
 

 

 

 

 

 

 	


 

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 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

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[b]

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jan 15, 2011 9:16 pm Post subject: model airplane servo

 	  Quote: 	
		  On Sat, Jan 15, 2011 at 8:55 PM, Robert Taylor <Flydad57(at)neo.rr.com (Flydad57(at)neo.rr.com)> wrote:

   --> AeroElectric-List message posted by: "Robert Taylor" <Flydad57(at)neo.rr.com (Flydad57(at)neo.rr.com)>

 

  I am interested in the possibilities of using an R/C servo for the pitch trim on my TigerCub.  Any and ALL details very welcomed! 	
 

      I know that there are many success stories that

      cite the use of R/C servos for moving things on

      airplanes. Just be aware that there ARE failure

      modes in these little guys that can cause a fast

      and total "hard over" motion to the mechanical

      limits of the system.



      I would not be able to get these products blessed

      for use on TC aircraft without some very convincing

      analysis and safeguards against such behaviors.



      Having your trim system drive to a limit in

      a few hundred milliseconds can really put some

      excitement into an otherwise boring day.



 

 

        Bob . . .

                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================



     [quote][b]

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