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Pull-Pull on throttle
I am wondering how pull-pull would work on my DLE 30cc throttle set-up? I do not have enough ny-rod to reach. I do have some high grade tubing and was thinking of running super heavy braided fishing line through the tubing to throttle arm. I was going to use the arm on servo to pull the line & let the tension on the carb spring to pull back.
Also what I do not like about ny-rod is that it changes length with temperature. Capt,n I may just try it...if it seems like any problem I can replace it. |
RE: Pull-Pull on throttle
Huh?
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RE: Pull-Pull on throttle
Sounds like a failure waiting to happen to me...[sm=surprised.gif]
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RE: Pull-Pull on throttle
The fishing line will change length just like the Nyrod?
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RE: Pull-Pull on throttle
Captinjohn,
I say go for it! Only question I have is; is the braided fishing line metal? If yes, could that cause an interference problem? If the line IS metal and IT does cause a problem, how about using a narrow weedwhacker line for the pul-pull. Just blurbing out loud. Good Luck. Mark |
RE: Pull-Pull on throttle
YOur Nyrod will not change length enough to even be detectable in engine performance, maybe a couple of thousandths of an inch with an 80 degree change in temperature over a 12 inch length.
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RE: Pull-Pull on throttle
A couple of years ago, I paid a guy to assemble a plane for me. He did pretty much exactly what you are suggesting. It worked fine and that airframe still flies today with that setup (He used Kevlar line for the Cable) The minus is that you are relying 100% on the spring to close the throttle off so you would really want a second option of killing the engine fom the TX (Such as a choke servo or TX operated kill switch).
IF it is simply a shortage of material you are worried about, do you have any small carbon tube and 2-56 or 4-40 threaded rod that will fit into it? Use some good Epoxy paste (JB Weld is best of all) and glue some threaded rod inside each end of the carbon tube. sort of a poor mans version of the Central Hobbies rod ends. |
RE: Pull-Pull on throttle
Well after cooking my wife some Fresh fish (Steelhead) on the oudoor grill...I hooked up the pull-pull on tthe throttle. It is just about a strait line to servo...but used about 10 inch tube for it to run in. I worked it by hand first at servo end....super smooth. I then hooked it up and tested it with TX. Seems real nice.
I got the line from a guy that buys the best line. He fishes Muskies with $25-$35 dollar lures that look like giant rapellas. This line is so strong....you could rip the arm off the carb if you wanted too. I am going to test for strech with another piece tomorrow. If I remember right...it does not. I have seen guys break fishing rods by jerking to hard to set the hook on braided line. Capt,nPS, I do have a cut-off button on TX. |
RE: Pull-Pull on throttle
ORIGINAL: captinjohn Well after cooking my wife some Fresh fish (Steelhead) on the oudoor grill...I hooked up the pull-pull on tthe throttle. It is just about a strait line to servo...but used about 10 inch tube for it to run in. I worked it by hand first at servo end....super smooth. I then hooked it up and tested it with TX. Seems real nice. As long as the line is in a straight run, I cannot see why this wouldn't work quite well! There are some good leaders used on fishing lines that are metal. That woudl also work. Or an offcut from a pull-pull wire |
RE: Pull-Pull on throttle
ORIGINAL: apalsson ORIGINAL: captinjohn Well after cooking my wife some Fresh fish (Steelhead) on the oudoor grill...I hooked up the pull-pull on tthe throttle. It is just about a strait line to servo...but used about 10 inch tube for it to run in. I worked it by hand first at servo end....super smooth. I then hooked it up and tested it with TX. Seems real nice. As long as the line is in a straight run, I cannot see why this wouldn't work quite well! There are some good leaders used on fishing lines that are metal. That woudl also work. Or an offcut from a pull-pull wire |
RE: Pull-Pull on throttle
probably fun to eat too ! :)
mate, as long as you use plastic linkage, they are no more of an antenna than 2-56 (or 4-40) music wire |
RE: Pull-Pull on throttle
sounds like you never met a fish you didn't like :D
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RE: Pull-Pull on throttle
ORIGINAL: dave de sounds like you never met a fish you didn't like :D |
RE: Pull-Pull on throttle
Any control wil work in pull-pull,as you've found out. The question is why? being a little short on some byrod did not rule out other materials equally suitable. Nor did it rule out a trip to the hobby shop. Gtta show them some love once in awhile. So come on and admit it, you just wanted to see if you could, right?:)
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RE: Pull-Pull on throttle
I keep meaning to hook up a throttle like this, and then load test while the servo is pulling full throttle against the spring to see what the servo current draw is, and if it is excessive. Has anyone done this??
AV8TOR |
RE: Pull-Pull on throttle
TOM, I was going to use nyrod, and I thought I had some. I just gave up looking and did try the braided line. But you are right....it is something I was going to try sometime. .You knowme... I love trying out ideas once in a while. The real test is when I run the engine...maybe tomorrow!!!! Best Regards, Capt,n
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RE: Pull-Pull on throttle
Depending on the length of the servo arm, I doubt there is enough load to worry about. I left the spring on my Taurus 43 and have no trouble with the batteries. Most of the throttle springs don't have much tension. A longer arm on the carb will reduce the load on the servo.
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RE: Pull-Pull on throttle
I started leaving the throttle springs connected on all of my engines about 2 years ago. Partly because I was too lazy to disconnect them (It does take about 2 seconds after all) but mainly because it gives me a shutoff when I make a mistake and have a linkage disconnect (which ironically hasn't happened to me on an engine that has the spring connected). I don't know the exact load figure but I do know it has made absolutley no difference to the number of flights I get in per flight pack charge.
Actually, thinking about this since reading the OP. This method could be an interesting way around some of the side carb engines that are difficult to align a throttle rod to a servo. Maybe some fishing rollers with a cable to change the direction of the pull pull Go on captin - you know you want to experiment more - this is a hobby after all :D |
RE: Pull-Pull on throttle
I have been using a "pull" arrangement on my gas engines for years with no problems
at all. I use Berkley 30# Nylon coated fishing leader. Works just fine. I have never tested the load from the return spring on the servo - didn't think it necessary. It really does simplify throttle hook-up - at least for me. Works for me. Dan |
RE: Pull-Pull on throttle
ORIGINAL: aussiesteve I started leaving the throttle springs connected on all of my engines about 2 years ago. Partly because I was too lazy to disconnect them (It does take about 2 seconds after all) but mainly because it gives me a shutoff when I make a mistake and have a linkage disconnect (which ironically hasn't happened to me on an engine that has the spring connected). I don't know the exact load figure but I do know it has made absolutley no difference to the number of flights I get in per flight pack charge. Actually, thinking about this since reading the OP. This method could be an interesting way around some of the side carb engines that are difficult to align a throttle rod to a servo. Maybe some fishing rollers with a cable to change the direction of the pull pull Go on captin - you know you want to experiment more - this is a hobby after all :D AV8TOR |
RE: Pull-Pull on throttle
With a true pull-pull (two lines under tension) you would be placing a side load onto the shaft connected to the throttle arm. Add the vibration present in the motor and you might end up with excessive wear, with the debris going right into the engine. I wouldn't do it.
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RE: Pull-Pull on throttle
I would leave the spring in place no mater if I used ny-rod or not. That spring keeps the throttle plate from vibrating ...maybe wearing the fit it shoud have. The pull at the servo is hardly excessive with a long arm on the throttle shaft. I even made a neat little adjustment set-up at servo end. I do not have time right now ...but I could hook up a digital meter in series with the servo & measure Milli-Amp draw as I work the throttle. lots of fun stuff.....lets see ....whats next!
Capt,nhttp://www.rcuniverse.com/forum/js/f.../lightbulb.gif |
RE: Pull-Pull on throttle
ORIGINAL: av8tor1977 I keep meaning to hook up a throttle like this, and then load test while the servo is pulling full throttle against the spring to see what the servo current draw is, and if it is excessive. Has anyone done this?? AV8TOR |
RE: Pull-Pull on throttle
ORIGINAL: captinjohn I am wondering how pull-pull would work on my DLE 30cc throttle set-up? I do not have enough ny-rod to reach. I do have some high grade tubing and was thinking of running super heavy braided fishing line through the tubing to throttle arm. I was going to use the arm on servo to pull the line & let the tension on the carb spring to pull back. Also what I do not like about ny-rod is that it changes length with temperature. Capt,n I may just try it...if it seems like any problem I can replace it. |
RE: Pull-Pull on throttle
I say it will work fine and for a long time. The only downsides are, current draw and the fact that your servo will not last as long. The motor will always be pulling against the spring.
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