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Discussion Starter #1
Tried to do a motor prop last year and failed. Trying again this year and failing again. I cannot seem to get the linkage set up correctly. I adjust it in one spot and it binds someplace else. I think I need a bigger space between the arms but is there anything else I need to do? When it does run it is very jerky and it shakes itself apart. Help!!

Here is the set up right now, I plan on using a longer bolt between the two arms. What else could I use for the guide in the front it moves a lot which doesn't help.

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looks like the bolt between he short arm and long arm is too tight. you should try a little longer bolt and 2 nuts (tighten the nuts against each other , making sure that the arms can move)
 

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Discussion Starter #4
I have the exact same set up for Jaak the scare crow

I just used a couple nuts to space it out. hold the nuts in place with thread lock (or hot glue)...and don't run the prop to fast for to long...intervals! I run mine at a full 12V but only for 4 seconds...and it is crasy at 4 seconds...any more and it would come apart....
How do you get it to only run for 4 seconds at a time?
 

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Agree with bert1913. The bolts are too tight, in this linkage you need to allow the arms to spin on the bolt. Use a longer bolt with 2 locknuts and it will work fine.

Running at 12v will shake your prop about. Maybe a bit less would be preferable.
 

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Scott, I don't think the distance between your linkage is your problem. I use a single metal washer on the outsides of my linkages and I separate them with a single nylon washer. I always use lock nuts to keep the proper tension. Make sure your linkages are parallel and that the holes going through them aren't too tight for the hardware causing them to bind up. You might want to get your motor closer to being directly underneath your armature pushing upward so there is less of a side load. :) See the video below.

 

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Discussion Starter #7
So I put in a longer bolt and that helped a lot. I do need to readjust the placement of things to get it to align better. I also need to anchor the guide tube of pvc I am using better it rocks too much.

How do I reduce the voltage? I have the wires on the slow setting for the motor but it still bucks like a bronco even at that setting. The power supply and motor both came from monster guts so that is what I have to work with. Maybe I should go back to the original idea of him just being static.
 

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Discussion Starter #8
Diabolik I like your set up in your video with the two guides it seems more stable. I will see if I have time to work on this more. I have other props to finish that I have a higher priority on. Although I guess I could put him out as static at first and then work on him after I get the other stuff done.
 

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as old man bakke says, reduce the voltage, but keep the amps up. if you get say a 12v 1amp supply, it would run slower, but would blow the power supply in no time (been there, done that). an alternative power source is the way to go.
 

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Discussion Starter #12
I would recommend finding a sturdier way to mount the wiper motor to the board without using that large hose clamp.
That might be part of the vibration problem.
Yes, Hauntedparts is kindly sending me a motor mount to use so I am going to re-engineer the whole set up once it arrives. I am also going to beef up the guide post in the front that holds the vertical in place, I think I am going to insert a couple of smaller pieces of pvc inside the larger tube so it has less room to wiggle inside the tube.

So we will see what happens with round 2.
 

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I usually keep the bolt shorter, and put two nuts right beside each other (in between the links), then use pliers to twist them against each other as tight as I can. That has worked well for me, and keeping the bolt shorter minimzes the slop and slack between each link.
 

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Hi Scottv42, I shipped you out a free wiper motor bracket and wiring harness. The bracket will help stabilize the motor and the linkage while the wiring harness will help you wire up the prop so you can easily select between low speed or high speed. Like the others mentioned, get yourself a lower voltage power supply / wall wart. 5 volts / 1 amp works great. Correction....I mean 12 Volt 5 AMP power supply.
 

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Discussion Starter #15
Hi Scottv42, I shipped you out a free wiper motor bracket and wiring harness. The bracket will help stabilize the motor and the linkage while the wiring harness will help you wire up the prop so you can easily select between low speed or high speed. Like the others mentioned, get yourself a lower voltage power supply / wall wart. 5 volts / 1 amp works great.
I didn't think 1 amp would be enough for the motor.
 

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Scottv42, I'm not an expert prop maker and others are much more experienced that I am ; and I am no mechanical engineer so I have had my difficulties with adjustments of motors and linkages as well but here is my two cents. From looking at your photo it appears that the bar connected to your motor does not pivot at the upper end. For my props to work property I have to allow the push rod to not only be fee moving at the motor end but it also has to be able to pivot at the upper end sort of like a steam engine push rod or the motor will bind. From your photo it looks like the upper end is bend on a 90 degree angle and then bolted solid to the PVC pipe. I would try putting a threaded bolt through a PVC cap and then put the cap on the PVC pipe where the push rod is bolted. Then take out the 90 degree angle and straighten the push rod and drill a hole in the upper part of the push rod and bolt it to the PVC cap allowing for it to pivot freely. I bet this will solve the problem. Also, if you want to reduce the speed of the motor why couldn't you use a motor controller. I have used potentiometers from Radio Shack to slow my wiper motor speed for about four years with no problems but got some good advice from CreepyCreations so this year I have replaced all of these with these motor controllers. I got this information from another member on this forum. I'm sorry but I don't remember who. I have tested them on my props and they really work well. I run my motors on both 12v lawn tractor batteries and 12v power supplies. You can adjust the speed of the motor and for $10 including shipping the price is right. Just a thought. Good luck. Don't give up on this project.
 

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No idea myself from the pictures, but as been noted... I find you need to leave a fair amount of slack on the bolts. That alone has given my mechanisims enough play to work at times.
 

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Discussion Starter #20
OK the rebuild is done and we have success! It works pretty well now, so we will see how it holds up. I will post a picture when I have time. All of the time I spent working on this thing I am now behind on my other props I wanted to do :mad:
 
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