Matronics Email Lists :: View topic - Flap Actuator Alternatives? (Limit Switches)

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Flap Actuator Alternatives? (Limit Switches)

Matronics Email Lists Forum Index -> Zenith-List

View previous topic :: View next topic

Author Message

nfivesl(at)yahoo.com
Guest

Posted: Thu Feb 16, 2006 6:19 am Post subject: Flap Actuator Alternatives? (Limit Switches)

William:



First and foremost, my project is not finished and has

not flown.  So take this for what it's worth.  



There's more to this discussion than money. I've not

heard a lot of talk on the limit switch issue but I

think it deserves a look.  



The ZAC supplied, costly actuator has external limit

switches that you must adjust.  These are fragile and

have a lot of nuts and bolts, wires etc. exposed.  I

looked at doing the same thing with an automobile

window or seat motor, but it brought me right back to

the exposed limit switches since the thing needs to

know to stop at end of travel.  



I ended up with a 75 lb. actuator that works very well

and has internal limit switches so the trick is to set

it up to use all of the travel in both directions. 

Very simple, really and it's a much cleaner

installation.  I read recently on this list where a

factory-built 601XL had a problem with an external

limit switch.  Predictable.  



Here are a few photos of what I ended up with.  There

are more photos on my "fuselage" page:



http://www.cooknwithgas.com/11_21_04_Flaps.JPG



http://www.cooknwithgas.com/11_17_04_Actuator.JPG



The last one has the part number for the actuator if

you look closely.  



I also looked into making a trim servo from an

automobile side-view mirror motor.   I got pretty far

with this and it was looking promising until

guess-what?  The limit switches just became too

complicated and bulky so I saved up some money and

purchased a RAC (MAC) servo.  The first thing I did

was take it apart and void the warranty to see what

was inside.  And what do you know it had some baby

limit switches tucked neatly inside. This little

device was worth every penny.  Here's a picture in

case you are interested:



http://www.cooknwithgas.com/RAC_Innards.JPG  



Here's my poor attempt at the same thing:



http://www.cooknwithgas.com/TrimMotor3.JPG



Have fun,



Scott Laughlin

http://www.cooknwithgas.com/

Houston, we have a working radio!  



--- William Murray <tall_tech_teach(at)yahoo.com> wrote:



 	  Quote: 	
		   Being a penny pinching school teacher, I found the

 price and weight for the spec'd flap actuator motor

 to

 be too much. My question is this..... have they

flown
	


 	  Quote: 	
		   with

 them yet? 25 lbs seems to be too small a force to

 overcome the wind pressure on both flaps at Vfe or

 below. How are other frugal builders actuating their

 flaps?

- The Matronics Zenith-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:

http://www.matronics.com/Navigator?Zenith-List

Larry Martin

Joined: 10 Jan 2006
Posts: 31
Location: Cabot, Arkansas

Posted: Thu Feb 16, 2006 7:08 am Post subject: Flap Actuator Alternatives? (Limit Switches)

In my humble opinion, 75 lbs is massive overkill.  Stop and think about it 

for a minute.  The ZAC system is a leverage system.  In other words the 

pressure needed at your hand, which is what the actuator load is 

duplicating,  is far less than would be needed at the actual flap.  I have 

no idea how much differential it is but would think some where around 5 to 

1.   In a 701 the flap control is located on the left side of the pilot near 

the floor.  If anyone thinks they can extend their left hand straight down 

and excerpt over 25 lbs of pressure then they are pretty strong.  Just for 

grins I put my left hand extended on a scale and tried to hold or push and 

was having a hard time and shaking at 21.5 lbs.   If you put your actuator 

as a direct connect to the flaps, then more power will be needed, but that's 

not the way to do it.  Twenty five lbs is more than sufficient for the 701.



Speed, I've have people tell me that my actuator was too fast.  My answer is 

to ask this question, "is it as fast as your hand moving the flap lever from 

0 to 30 degrees in one swift move?"  The answer is NO.



Larry, N1345L, www.skyhawg.com

---

- The Matronics Zenith-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:

http://www.matronics.com/Navigator?Zenith-List

_________________
701 with a Harley, www.skyhawg.com

japhillipsga(at)aol.com
Guest

Posted: Thu Feb 16, 2006 10:06 am Post subject: Flap Actuator Alternatives? (Limit Switches)

Scott, I just read the post about a flap motor actuator that weighs 75 pounds. That's got to be a mis- print, isn't it ? 

 

--

- The Matronics Zenith-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:

http://www.matronics.com/Navigator?Zenith-List

craig(at)craigandjean.com
Guest

Posted: Thu Feb 16, 2006 1:35 pm Post subject: Flap Actuator Alternatives? (Limit Switches)

Another alternative is to use a "Super" radio controlled  aircraft servo.

Some of these put out many pounds of thrust as they (like the MAC servos)

take a small high speed motor and gear it way down. They are rated in many

pounds of pounds of thrust. Control then it with this "Extremely General

Purpose Non-MAC SERVO CONTROLLER" from Perihelion Design:



http://periheliondesign.com/moreproductsfiles/ServoController.pdf



This general approach can be used to move "things" from the control panel in

many other situations.



-- Craig



--

- The Matronics Zenith-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:

http://www.matronics.com/Navigator?Zenith-List

craig(at)craigandjean.com
Guest

Posted: Thu Feb 16, 2006 1:41 pm Post subject: Flap Actuator Alternatives? (Limit Switches)

Actuation speed is not a problem unless the motor coasts in which case the

motor over-shoots. There is a way to wire diodes into the switch circuit

such that they "short" the windings which acts as a break. "All" I have to

do is find the schematic for this.



-- Craig



--

- The Matronics Zenith-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:

http://www.matronics.com/Navigator?Zenith-List

Display posts from previous:

	Matronics Email Lists Forum Index -> Zenith-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum