Linear Actuator

[skippydiesel]

21 minutes ago, BrendAn said:

i think nev has hit the nail on the head. simple is best. a cable or rod is nearly foolproof and you don't have to wonder if your chinese electrics are going to fail.

 

My friend, is it possible, that you did not read the proceeding comments, from me?

The traditional system(s) of Cole Flap actuation, present a series of chalanages, I do not wish to address.

The electrical solution, long since adopted in the automotive world , is my proffered concept.

The concept has been tested - It works! -  fact!

Unfortunatly I have yet to find a suitably robust Linear Actuator of the correct specifications, that will give a durable service - this is why I asked the question in my opening comments.

So I ask you again -Are you able to recomend a supplier of quality linear actuators that may suit my purpose??😈

[onetrack]

Skippy, have you tried the company listed below? Despite your (and my) abhorrence of Chinese-made parts and components, it's becoming extremely difficult to find anything that is not manufactured there now.

 

I've tried in vain recently to acquire bearings that are not made in China, and despite buying "quality, brand names" (including the finest Japanese and European bearing names), I've continually been upset to open the "quality" box, and find "Made in China" stamped on the bearing!!  They have won the manufacturing war by sheer volume, by constant "competitive" pricing, and by being able to supply parts/components rapidly, in vast numbers.

 

The car industry is next. Chinese cars will dominate the world within 5 years, I reckon. I read where BYD have 1,000,000 employees, and 110,000 engineers!! FFS, why would anyone even try to compete??

 

Linear Actuators, High Quality and Low Cost

WWW.MOTIONDYNAMICS.COM.AU

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Explore our premium range of Linear Actuators (12V-24V), offering high performance with force capacities from 200N to 7000N and strokes from 100mm to 500mm (IP65 rated). Comparable to top global brands...

 

Edited Thursday at 03:43 AM by onetrack

[BrendAn]

47 minutes ago, skippydiesel said:

My friend, is it possible, that you did not read the proceeding comments, from me?

The traditional system(s) of Cole Flap actuation, present a series of chalanages, I do not wish to address.

The electrical solution, long since adopted in the automotive world , is my proffered concept.

The concept has been tested - It works! -  fact!

Unfortunatly I have yet to find a suitably robust Linear Actuator of the correct specifications, that will give a durable service - this is why I asked the question in my opening comments.

So I ask you again -Are you able to recomend a supplier of quality linear actuators that may suit my purpose??😈

I did read your comments. I think its Much better to keep it simple.  No I don't know where to get a quality actuator. 

[skippydiesel]

53 minutes ago, onetrack said:

Skippy, have you tried the company listed below? Despite your (and my) abhorrence of Chinese-made parts and components, it's becoming extremely difficult to find anything that is not manufactured there now.

 

I've tried in vain recently to acquire bearings that are not made in China, and despite buying "quality, brand names" (including the finest Japanese and European bearing names), I've continually been upset to open the "quality" box, and find "Made in China" stamped on the bearing!!  They have won the manufacturing war by sheer volume, by constant "competitive" pricing, and by being able to supply parts/components rapidly, in vast numbers.

 

The car industry is next. Chinese cars will dominate the world within 5 years, I reckon. I read where BYD have 1,000,000 employees, and 110,000 engineers!! FFS, why would anyone even try to compete??

 

Linear Actuators, High Quality and Low Cost

WWW.MOTIONDYNAMICS.COM.AU

---

Explore our premium range of Linear Actuators (12V-24V), offering high performance with force capacities from 200N to 7000N and strokes from 100mm to 500mm (IP65 rated). Comparable to top global brands...

 

Correction: I am great admirer of the Chinese and their work philosophy. Industrially, scientifically & possibly militarily we have much to be concerned about - they are consigning us (the West) to history.

 

In my lifetime I have seen the rise & rise of Asian industry.  Look at the high quality products from the Japanese & Koreans - in my youth much sneered at. The Chinese & Indians have put rockets/satellites into space. Sure they give the World cheap low quality products but they can & do, deliver as high a quality as we are willing to pay for.

 

Thanks for the WWW.MOTIONDYNAMICS.COM.AU - I have written to them asking for their recommendation - Unfortunatly my browsing of their website, suggest even their smallest actuator is likly many times the weight/size of what I would like.😈

[facthunter]

You are over complicating a non  existent problem. There's practically NO load  involved and you can feel if it's Jammed and increment the adjustment. Same with Flaps Best Hand operated where if there's a need for change it's quick. With NO assymetry protection, powered flap is a risk. YOU don't NEED this $#!t And it goes On and On with you paying no heed to what others say, by and large.. Why bring it up here IF you are already convinced? Nev

[skippydiesel]

Hi onetrack. This is the smallest 25 mm LA that MOTIONDYNAMICS have on their web page:

This is dimensional idea (not the actual unit) of what I am after:

 

[facthunter]

GEEZ Skip. You wonder why people hesitate to respond to you.  Nev

[Garfly]

7 hours ago, Marty_d said:

There was an interesting cowl flap shown somewhere here, French bloke had it on top of his cowl to release heat while on the ground.

From memory it was hinged forward of the midpoint of the flap and lightly sprung, so at low speeds it would open but any wind pressure would close it.

This'd be the post you're referring to, Marty.  As you say (and AFAIK) the device is only meant to reduce heat soak under the cowl on the ground.

 

 

[skippydiesel]

Nice one Garfly! 😈

[onetrack]

Skippy, you're obviously looking for a micro linear actuator, as compared to a regular size industrial linear actuator. AFAIK, the major manufacturers/suppliers of micro linear actuators, are those people in the RC controls industry.

 

As a last resort, you could try RS Components. They will supply nearly anything electrical (and promptly), but usually at aircraft-parts-style pricing. The major advantage of RS Components is their website is very good, and you can select all types of technical product criteria in your part search - such as stroke, threads, lengths, voltages, loads, etc, etc - to go pretty accurately to the product you're looking for.

 

RS sell micro linear actuators from a company called Actuonix Motion Devices, who are Canadian, and who were once part of Firgelli, before they decided to operate as a stand-alone company.

 

Electric Linear Actuators | RS

AU.RS-ONLINE.COM

---

Browse our Electric Linear Actuators offer. Place your order today for our Electric Linear Actuators.

 

[RFguy]

Skip you are going to have to put some numbers on the requirement.

Force - I cannot beleive much unless it is acting as a bucket scoop ,But it WILL have some of the pressure of the cowl insides... You would be able to make a reasonable estimate of the upper limit of the pressure on the cowl flap. 

Travel ? .

 

Many Model RC-servos will do the job you want , since I gather you are fine if it doesnt work. 

 

[onetrack]

The data sheet for a typical 20mm stroke Actuinox Motion Device linear actuator, is linked to, below. Note that the "maximum duty cycle" is only 20%, and they also note that "repeated stalling of the actuator against a fixed load will shorten the life of the actuator".

This indicates to me that the micro linear actuators are not really "industrial grade", nor really suitable for full-size aircraft use, where you'd normally expect a substantial degree of durability and reliability. 

 

https://docs.rs-online.com/f045/0900766b814ad9d3.pdf

[skippydiesel]

18 minutes ago, onetrack said:

The data sheet for a typical 20mm stroke Actuinox Motion Device linear actuator, is linked to, below. Note that the "maximum duty cycle" is only 20%, and they also note that "repeated stalling of the actuator against a fixed load will shorten the life of the actuator".

This indicates to me that the micro linear actuators are not really "industrial grade", nor really suitable for full-size aircraft use, where you'd normally expect a substantial degree of durability and reliability. 

 

https://docs.rs-online.com/f045/0900766b814ad9d3.pdf

"repeated stalling of the actuator against a fixed load will shorten the life of the actuator".

I do not understand.

The LA's I have been using have two wires. 

Switch down - current drives motor - system extends -  "hits" stroke limiter and cuts off current.

Switch Up - current reverses motor - system retracts - "hits" stroke limiter and cuts off current.

Note: There is no need for an interim position ie its either fully open or fully closed

The above system can not repeatedly stall, as stroke limiters shut of current/drive at the end of each stroke movement.

😈

[sfGnome]

The stall will occur if the actuator can’t reach the limit switch for some reason (eg too much load).

[skippydiesel]

2 hours ago, RFguy said:

Skip you are going to have to put some numbers on the requirement.

Force - I cannot beleive much unless it is acting as a bucket scoop ,But it WILL have some of the pressure of the cowl insides... You would be able to make a reasonable estimate of the upper limit of the pressure on the cowl flap. 

Travel ? .

 

Many Model RC-servos will do the job you want , since I gather you are fine if it doesnt work. 

 

I don't follow.

I have been using LA's with a claimed 19kg extension force - many times what might be required to open a small flap, to say 30-45 degrees. 

The pressure, on the closed flap is minimal, as its function is a "choke' or restriction, not shutting of the air flow completely.

The lower closing force of the LA is equally of no concern, as the air pressure against the flap will assist the retraction.

The LA's, for their short life, have worked well.

As earlier mentioned - a post-mortem of the first LA found that the motor still ran, the extension/retraction system still worked, however the stroke limiter circuit had failed, thus not allowing the reverse of current polarity to retract the system.

The following are the specifications I have been working to:

·         Some resistance to moisture, dust & temperature. The actuator may be inadvertently exposed to water, during cleaning and in operation, air temperatures to 60⁰C.

·         Extension range 20-25mm. 

·         Working speed 5-10mm/sec (negotiable)

·         Thrust 20kg (negotiable)

·         Installed length (retracted) 75 -80 mm 

·         Fully extended/retracted, built in, electronic limit switches (existing remote switch to reverse polarity/direction of movement)

·         No power “lock” in fully extended/retracted position.

·         Constructed of corrosion & vibration resistant materials

·         Current mountings 4mm ID both ends but could be modified.

·         Automotive standard 12V electrical cable

 

The extension of 20-25 mm, will give an approximate 45 degree flap movement.😈

Edited Thursday at 11:22 AM by skippydiesel

[skippydiesel]

5 minutes ago, sfGnome said:

The stall will occur if the actuator can’t reach the limit switch for some reason (eg too much load).

Ah! 😈

[Blueadventures]

There is no description of the flap your moving. Maybe it’s pressed up hard in its track that then act as a break. You need to provide more info and image of what’s not working.

Edited Thursday at 09:12 PM by Blueadventures

[skippydiesel]

1 hour ago, Blueadventures said:

There is no description of the flap your moving. Maybe it’s pressed up hard in its track that then act as a break. You need to provide more info and image of what’s not working.

Cowl flap is the full width of & conforms with, the shape of, the underside of my cowling and aproximately 150 mm wide. Hinged at the afte edge of the cowling (no possibility of jamming).

 

When closed, conforms with/looks like, an extension of cowling bottom. 

When open, goes to about 45 degrees down,

 

Will try & find a photo