skippydiesel

It is almost certain, that manned fighter/bomber aircarft are close to being redundant - the future will be drones & rockets of all shapes & sizes. This trend is also going to happen on/under the sea - so much for billion dollar subs. Military personnel will be a long way from the front line and relative, to past/current conflicts, few in number. The featured aircraft, if it isn't a computer generated fraud, is but part of a game of one upmanship - a distraction/propaganda 😈

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

Ah! 😈

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.😈

"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. 😈

Nice one Garfly! 😈

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:

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.😈

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??😈

Thanks for the correction in terminology. ".......I could knock up a simple one for you in probably less than an hour." As for simple - perhaps I am overcomplicating, the system, in my mind; Ratios to be considered - Input length of actuating button movement : reversing arm linkage length & location of input/output cables : flap movement Acquisition of suitable button & double acting cable system Will button fit in switch location on panel Measure button movement Dont have a reversing linkage, but like you could probably make one. Unlike you would take several hour/days (after acquiring materials) & include method & location of mounting. Mounting location may take several days to sort out, IF practical at all. I guess the position of the firewall hole, for the cable to Flap, would arrive as part of installation process - not happy with the idea of additional holes in firewall. I do have a flap that is capable of moving through 90 degrees (I will limit to Max 45 degrees) - a suitable mounting for the actuating mechanism to attach, would have to be fabricated Simpler (to me) to mount a two position reversing polarity switch (JayCar) Run a suitable 12V wire to power source (via fuse JayCar) and to Linear Actuator (have wire on hand) Mount Actuator (seeking advice on supplier of reliable unit) such that it will open & fully close Cowl Flap What's not to like??? Thanks for the "The Bullet Series 23 Cal. " suggestion from Firgelli - I had looked at these, unfortunately the closed length is around double what I require (see opening specifications). IF the Bullet is the only viable option, may have to reconsider existing mounting system. Firgelli used to do a much shorter/smaller range of Actuators (have one on my desk but seem to have dropped them). Firgelli (Canadian) likly have their actuators made in China & charge about x 10 the price of the very similar looking eBay offerings (see my opening comments). 😈

Thanks for all that RF Duty Cycle: Not sure how this translates in this context. The flap goes from fully closed/open in about 1-2 seconds. Current only flows between fully closed/open when limit switch activates. I thought a claimed 19 kg extension (pushing) force would be many times the effort required to open the flap ie a conservative capacity. Closing the flap (pulling force)will be assisted by air pressure, so much reduced effort required. Linear Actuator RS! so not able to perform any tests at the moment - do you know of a quality Linear Actuator supplier?😈

Why did I decide on a linear actuator to operate my Cowl Flap?? Perhaps at odds with the concept of mechanical/traditional operation of a small aircraft cowl the linear actuator present's as an easier/simpler way of the pilot opening/closing the flap. I can just hear you now - Naa! pull/push cable (traditional) must be the simplest. The traditional system would require; Another hole in my firewall For intuitive action (In for Close/Out for Open) a direction reversing cam would have to be made/purchased/mounted - not simple! A suitable location, on panel, for the Cowl Flap button would have t o be found (Sonex panel real estate in short supply). Reliability - Almost failure proof. Linear Actuator; Electrical wires to control/energise Actuator pass through existing firewall hole - no modifications. Two way toggle switch on instrument panel, Up for Close / Down for Open - small LED to one side of switch red for down/green for up. No issues with working out cam rotation/arc ratio to flap movement. Actuator extension movement must be matched to Flap movement - not hard. Linear Actuator - looks like a small hydraulic ram - is mounted in the exit air hole at one end & on cowl flap at other. System works very well, that is until Actuator stops working. Reliability - If I can find a suitable Actuator (hoping you can help) the system should be reasonably safe. Fail open - There is a small amount of extra drag/reduced/ engine systems may stay cooler than optimum performance - barely noticeable. Fail closed - There is the potential for increased engine system temperatures during Climb. The pilot may notice LED stayed green - abort TO. If in Climb should be able to manage this by reducing engine power, leaving prop pitch in Fine and returning for a landing. In the absence of a suitable Linear Actuator, I think I will move to a very simple system - Summer: Exit Ait Open / Winter: Exit Ait Choked (partially closed)

??????? Please explain 😈

Hi RF, I thought that supplying the web page would have given you all the info. you need. I am not well versed in all of the options you have listed - short answer - don't know suspect "ball screw" The units(s) I selected appear to have all the characteristics I need to do the job - they just don't last. Both failed in the open position, which may be a good thing. On dismantling the first failure, it seems that the electronic limit switch failed - which in my understanding meant that the electrical polarity could not be reversed ie no retract action. The electric motor ran perfectly when connected to 12V. The screw mechanism extended retracted when a screwdriver used to provide rotational force. Circuitry so small - beyond my capacity to repair. They claim a near 20kg extending force, which should be more than enough for a small cowl flap. Sonex don't fit cowl flaps as part of their plans/kit offering - previous non conforming enquiries have not gone well.😈

Happy New Year to the Forum Brains Trust I have had bad luck in the use of linear actuators, to operate my cowl flap. The first one lasted about 30 hrs before failing to retract, the second an hour. I have been using the following (12V variant) supplied by CarryMart. https://www.carymart.com/21mm-dc-6v-12v-24v-micro-electric-linear-actuator-max-thrust-42-lbs-188n-19kgs-p-2484.html I was attracted to CarryMart because they have comprehensive specifications for their products (unlike identical looking ones on eBay). The specifications of the above unit fit my application. FYI: By the time a received the actuator, it cost about AU$100, x4-5 the price of an eBay similar product and it took 30 days from order to dispatch and another 10 days to arrive. Comprehensive specifications & cost, are not a reliable indicator of a quality product/service. I am hoping some of you may have been down this track and can recomend a supplier of reliable actuators. 😈

When I wanted to remove an ad, I contacted Admin😈

If its sold, should you remove the advertisement???😈

The key statement in that whole paragraph😈

"People can make up their own mind about lights. I happen to think they can be useful at times. Even without that little episode, I would have put them on my plane anyway just because I like them. The extra switches on the panel look nice too." The only part of your statement I agree with.😈

"In your dreams" my friend. More likly you/the pilot have made that last look/check, straight down the runway & slight up, the glidescope, before entering the active - WOW!!! that aircrafts lights shows up realy well. REALITY! the aircraft will be on final, perhaps a kilometer away, silhouetted against the sky, you would have seen it anyway. This is a classic bias reinforcement story. As for the tower - In most instances the tower will have a perfect view of landing/circuit traffic, light on/off. Also, if they are not asleep, will know in what direction to look, with or without radio calls to assist. On final, the tower will be viewing, the aircraft, at some point, against the terrain (lights show up beautifully) So the combinator of knowing where to look, the all important obligatory radio calls (giving location/intention) is all the tower need in Day VRF. 😈

Nothing to do with aviation , sorry. Can't help but give you this little gem of Americanisation: Within Amazon, the parcel dispatch facilities are known as "Fulfilment Centres" This explains that warm tingly inner glow I get when receiving a parcel from Amazon🥵

The way I "see" it is that we all expect/hope that lights will somehow improve airborne visual acquisition of another aircraft. Our experience on the ground tells us that a light will grab our attention; of another vehicle, indicators, danger, traffic controls, room occupied etc, etc. A further reinforcer of this, is how well aircraft/lights can be seen from the ground - people forget that most often they know where to look first because they hear the engine(s) and/or they are a pilot, so look to the circuit, then the is dramatic view of an aircraft on final (again a known location/direction) with is landing lights on - what an entry!!! So it goes against this experince/intuition, that they just don't work very well iday VFR conditions. Many/most can't (?) separate their terrestrial experince from what happens in the air. Their expectation is so strong, they reinforce their own bias, by relating a story/event where suddenly they saw the other aircraft because it had flashing lights - in reality it is most likly they saw the aircarft & its lights at the same time, after their attention was drawn to it location by a radio transmission.

If you know where to look😈

Rgmwa - I have attempted to give what I feel is the empirical rather than the emotive position. The subject of aircraft lights always attracts strong support - its a no brainer good thing - right? Someone reading this "thread" need to know that despite the apparent safety benefits, the reality is a long way from what might be expected.😈

I think all four are brokers ie not insurerse. In the event of a claim it is the insurers who pay out or not, in in hole or part.😈