Reverse thrust mechanism

[Guest seev_39]

Hi George and all,You got it right. Need is the best incentive. Me, like yourself George, live in a place where technical supplies are scarce and expensive and that was the couse for looking into different possibilities.1. Making the parts is done the way you put it above. You have to be carefull about the artifical rubber mold. It is flexible and must be placed back in the box where you casted it the way as you began with, otherwise you get the final product distorted.2. I attached 4 pictures. One of them show gear wheels with a 1:3.5 ratio for throttle and triming (throttle handle moves 70 degrees while pot rotates 250 degrees). In the trim the ratio is opposite. The wheel rotates more then three times while the pot rotates once. I think this is a good ratio because the active part of the trim is very limited.How I did this wheel, please don't laugh. I took two plastic container tops with suitable diameters, cut out 8 mm steel strips from a cucumber tin container and bent the teeth with a pair of pliers. The teeth are 5 mm deep each. The tricky part is to make a closed ring from the strip. You do it with a solder (your kid can hold the strip while you solder it, let him, or her learn). After the ring is closed put it over the cover and play a little with a pointed pliers until it looks even. Then fil all cavities with clay. Because the teeth are big the tolerances do not matter so much, anyway the product doesn't have to pass Boeing's inspection and it will cost you a fraction of their flap gears. I drilled the 6 mm center holes after casting the gears, but I guess the holes can be part of the mold on the first place.

[tigert 0]

Oh man, this is just awesome :-)Nothing to be ashamed of in the cucumber can. It's more of a shame if you spend money on something you can get far cheaper with a bit of a clever thinking.I was also thinking about using polyurethane for casting knobs etc. Korry has all the dimensions of their knobs on their website, so it would be pretty interesting to cut and carve one knob from wood or whatever and cast a mold, then make a bunch from urethane.But yeah, this is pretty ideal for stuff like throttle handles etc. as well.. did not think of that, thanks for the idea.Do you know if it is possoble to mix dyes into the urethane to colorize it? Some titanium dioxide could make nice "boeing" white handles I guess, if the chemical process does not get disturbed.My friend used plain, old fashioned ink to make epoxy resin black, so maybe it might work.Tuomas

[Guest MikePowell]

It is indeed possible to add color to plastic casting compounds. Tap Plastics sells the resins and dyes on the west coast of the US. Probably not real convenient to you, but their web site www.tapplastics.com does have a little information on the materials and their use. I would not be surprised to find that the same colorants used with acrylic house paints would work with casting resins.Mikewww.mikesflightdeck.com

[tigert 0]

Hehehe, so I went and bought Polyester resin stuff (that thing has the most evil odor you can think of btw :-P - better have GOOD ventilation.. )I did some test castings of throttle levers. Basically flat aluminium with a hole on the end, where I put a bolt and a nut and two more nuts that hold a washer in between them in the middle of the bolt - just some odd shaped stuff for the resin to stick to and to add strength.So for a first test I think this turned out pretty promising!http://tigert.gimp.org/vatsim/cockpit-stuf...-throttle1.jpeghttp://tigert.gimp.org/vatsim/cockpit-stuf...-throttle3.jpeghttp://tigert.gimp.org/vatsim/cockpit-stuf...-throttle5.jpegInteresting stuff if you ignore the smell :-)Yea, that is cough medicin measurement cup I cast the "handles" with :-) My friend has used black ink from ballpoint pens to colorize the polyester black, need to try that for the "production run" :-)Tuomas

[Guest]

Hey TuomasThat looks really promising! :-jumpyGot to remember this for my production stage. Any ideas on using clay for more oddly shaped casting?I guess your friend mixed the ink into the polyester right?TGIF

[Guest seev_39]

Hi Tuomas,I forgot to tell you it stinks, it also needs latex gloves while handling, at least that;s what the lady who sold me the materials say.When you prepare the molds from the artifical clay you have to insert some kind of scafoldings (wood or something) in the mold, because for several days the clay is too soft for handling, especially if the pieces are big. You work on one side of your handle, or knob, and then hups!!! the other side gets out of shape. I some time wonder how kids manage to work with this clay or other clays. That isn't a work for old trembling guys.Have fun Seev

[tigert 0]

>I guess your friend mixed the ink into the polyester right?>>TGIFYeah, he mixed the ink into the polyester stuff.>I forgot to tell you it stinks, it also needs latex gloves >while handling, at least that;s what the lady who sold me >the materials say. Yeah. One of the worst chemicals you can get without a buying permit I guess :-)>When you prepare the molds from the artifical clay you have >to insert some kind of scafoldings (wood or something) in >the mold, because for several days the clay is too soft for >handling, especially if the pieces are big. You work on one >side of your handle, or knob, and then hups!!! the other >side gets out of shape. I some time wonder how kids manage >to work with this clay or other clays. That isn't a work for >old trembling guys. So you make a "positive" object with clay and then use casting rubber to cast a mold from it? I have never seen/tried that rubber stuff, but I guess it would be fun to play with. Tuomas

[Guest seev_39]

>So you make a "positive" object with clay and then use >casting rubber to cast a mold from it? I have never >seen/tried that rubber stuff, but I guess it would be fun to >play with. Hi Tuomas and Tigert,I Think I used a wrong word in my first explenation probably because of a language barrier, sorry for that. What I meant is the following;First you make a clay model (not a mold - the term I used). Then you cast artifical rubber on it, and after it dries you take the clay model out (through a cut you make) and cast polyester or any other poly resin into the cavity. Again, after it hardens, you take it out and then you have your new piece.The rubber I use is Rhone-Poulenk RTV-2 which dries in about 24-48 hours. The hard polyurethan is the same one used also in the boat repair business, I have no idae who is the producer.I came to the idea after reading an article on "lost wax" casting, which as old as civilization itself.Attached are 2 pictures of the rudder knob I use on my desktop cockpit (too lazy to use my feet for a couple of hours).Seev

[Guest GeorgeDorkofikis]

You have small parts to make, or you don't want to use polyester and want to use plastic?Do you do plastic modelism?.. No? Well you should start!...Use the remaining plastic!How? Heat them and melt them. Do NOT heat them too much. You want to melt them, not put them on fire. Use a pot with boiling water and another pot (metal or glass) with the plastic inside. Steer them slightly and make sure you use the same kind of plastic everytime.Then poor the melted plastic into the mold and allow it to dry...Just crossed my mind!.. Used to do that for broken parts in plastic modelism!!!!Cheers,George DorkofikisAthens, Greece

[tigert 0]

>Hi Tuomas and Tigert, Heh, I'm only one person :-)>I Think I used a wrong word in my first explenation probably >because of a language barrier, sorry for that. What I meant >is the following; >First you make a clay model (not a mold - the term I used). >Then you cast artifical rubber on it, and after it dries you >take the clay model out (through a cut you make) and cast >polyester or any other poly resin into the cavity. Again, >after it hardens, you take it out and then you have your new >piece. >>The rubber I use is Rhone-Poulenk RTV-2 which dries in about >24-48 hours. The hard polyurethan is the same one used also >in the boat repair business, I have no idae who is the >producer. Oh, then I understood correctly. I need to try that rubber thing, just need to find a place that sells it. I guess hobby shops or such might be a good starting point. Though "cheap" and "hobby store" usually dont mix too well..>Attached are 2 pictures of the rudder knob I use on my >desktop cockpit (too lazy to use my feet for a couple of >hours). Hmm, did not see any images though..?Tuomas

[Guest seev_39]

Hi Tuomas >>Attached are 2 pictures of the rudder knob I use on my >>desktop cockpit (too lazy to use my feet for a couple of >>hours). >>Hmm, did not see any images though..? >TuomasDon't Know what happened with the images. I will try again.You are right about the pricing of hobby shops. The alternative is chemical material suppliers, but then you have to consider larger quantities. The materials I bought are; Polyurethan (hard type); material A - 1lb, Material B - 1lbArtificial rubber; Material A - 1lb, hardner - 5% (it comes in one standard package)Clay; 1 kg.two additional materials; silicon spray (to avoide sticking), cleaning chemicals, measuring cup, etc.The type of polyurethan I use gives a white color when solid. As for a different color my supplier advised to use car paint (the one sold as spray in small canisters).The whole thing is a little expensive and I intend to look into alternatives.Keep flying and don't poisen yourselfSeev

[tigert 0]

>Don't Know what happened with the images. I will try again. Okay, now they are visible. Nice!>You are right about the pricing of hobby shops. The >alternative is chemical material suppliers, but then you >have to consider larger quantities. The materials I bought >are; >Polyurethan (hard type); material A - 1lb, Material B - 1lb >Artificial rubber; Material A - 1lb, hardner - 5% (it comes >in one standard package) >Clay; 1 kg. >two additional materials; silicon spray (to avoide >sticking), cleaning chemicals, measuring cup, etc. >The type of polyurethan I use gives a white color when >solid. As for a different color my supplier advised to use >car paint (the one sold as spray in small canisters). >The whole thing is a little expensive and I intend to look >into alternatives.Korry website has pretty accurate pictures about knobs they make with exact dimensions, so if one could construct a dummy knob (or CNC a "negative" knob shaped hole to some mold material) it would make pretty nice knobs for home simulator use.How did you attach the thing to the rotary switch? Just drilled a hole to the knob (or was it in the mold already?http://www.korry.com/knob01.htm is one example of their specs.Now if you make them from translucent polyester and later paint them with some paint that blocks light, but leave the direction indicator "stripe" unpainted, those knobs can be backlighted if you put a few leds or small light bulbs under the knob.Tuomas

[Guest seev_39]

>How did you attach the thing to the rotary switch? Just >drilled a hole to the knob (or was it in the mold already? I made the 6 mm hole with a home stand drill after casting. It fits the pot metal shaft with a little pressure, but I assume you can have the hole as part of the mold.>Now if you make them from translucent polyester and later >paint them with some paint that blocks light, but leave the >direction indicator "stripe" unpainted, those knobs can be >backlighted if you put a few leds or small light bulbs under >the knob. Seems a good idea, creativity is unlimited. One problem is that at a certain point of time I want to have my final product but every time I go into this forum I change my concept. Also I don't have yet solutions for some electrical problems, like how you get the "g" landing gear up/dn function to work with a two way lever, or how you make sequance commands on an additional keyboard - like how is CTRL+E done with one button press, etc.

[tigert 0]

>>How did you attach the thing to the rotary switch? Just >>drilled a hole to the knob (or was it in the mold already? >>I made the 6 mm hole with a home stand drill after casting. >It fits the pot metal shaft with a little pressure, but I >assume you can have the hole as part of the mold. >>>Now if you make them from translucent polyester and later >>paint them with some paint that blocks light, but leave the >>direction indicator "stripe" unpainted, those knobs can be >>backlighted if you put a few leds or small light bulbs under >>the knob. >>Seems a good idea, creativity is unlimited. One problem is >that at a certain point of time I want to have my final >product but every time I go into this forum I change my >concept. Also I don't have yet solutions for some electrical >problems, like how you get the "g" landing gear up/dn >function to work with a two way lever, or how you make >sequance commands on an additional keyboard - like how is >CTRL+E done with one button press, etc. Check out the FSUIPC configuration dialog. You can map a key to "Gear Up" and another key for "Gear Down"For more complex stuff you want to have something else than a plain keyboard card. If you can solder you might want to check out FSBUS - www.fsbus.de, that is what I use as well, and it is rather nice thing. It contains its own software so there is no need to write code yourself (no big personal interest in programming here) ..Another choice is EPIC but that costs *a lot* and the modules cost still more so it is a pretty expensive solution, way beyond my budget.People have also used the Hagstr

[Guest]

Hello George,Can you post the electronic schematic again? i think the server deleted it already...ThanksRyan