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Skookum Robotics Skookum Robotics SK-360 SK-540 & SK-720 Digital Flybar |
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06-15-2008, 03:18 AM | #1 (permalink) |
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Another way to mod a Trex 450 Head
After trying many different ways to Make my 450 head flybarless. I decided I DID Not want to use reducing arms as I am taking a minimalist approach. I noticed when I cut the unused ends of the mixing levers that I used in the anti-rotation bracket they slot perfectly into the blade grip Ball link end to Extend the ball away from the grip axis! You just have to slightly round the Edges to allow for a tight fit. Then just ACCURATELY! drill holes to allow you to bolt them In place. (Mine are a bit rough but I plan to clean them Up a bit)
I do not have my SK360 yet so I am unable to test them out. They really stick out alot right now but I can shorten them if it reduces the throws To much, I will just have to wait and see. HEck the color even Matches!! -Do you guys think it will work?
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
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06-15-2008, 04:09 AM | #2 (permalink) |
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Wopuld hate to think what would happen if one of the Allen bolts holding the extensions on were to vibrate loose in flight :-(
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06-15-2008, 02:08 PM | #3 (permalink) |
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Well The fit is very tight and the bolts used are as long as possible (much more thread contact than a linkage ball) and are loctited in place. so I am assuming that Their Failure would be less probable Than say any other ball link coming loose or Falling off, even though there will be alot of force on them. Still There are far less possible failure points on a Simple head design compared to one with a flybar, But a failure in This Head would defiantly Bring her down hard! We will just have to wait and see ( :
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
06-15-2008, 08:17 PM | #4 (permalink) |
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Join Date: Oct 2007
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Should work fantasic until it fails. Hopefully the fantastic part of the previous sentence lasts long enough for a suitable solution from heli manufacurers or the aftermarket.
Don't get me wrong, I'm not knocking your design. My Titan has a little "Mickey Mouse" going on and it will stay that way until someone offers a quality alternative. Good luck and thanks for sharing. |
06-15-2008, 08:39 PM | #5 (permalink) |
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Ya Thats why I love this hobby! Seen another guy using blade 400 grips, they seem to look good but I think this Metal design will hopefully outlast the plastic one?? but only time will tell
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
06-17-2008, 10:00 PM | #6 (permalink) |
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Skookum, (or others that can help)
what is the Ideal Ratio OF swashplate ball Distance to Grip ball distance (from Axis)? When not using reduction arms ? Right now my swashplate balls are 15mm out from center and grip ball 22mm out from center (of main shaft). So i think that would mean that I have a 32% reduction in movement??? Does This mean anything to You guys or am I Off in another world??? I am using servo horns with the ball 13mm out. Thanks
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
06-17-2008, 10:09 PM | #7 (permalink) |
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Join Date: Oct 2007
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What are your swash percentages and cyclic/pitch ranges? I don't know if anyone knows the magic number relative to head geometry, but swash percentages and servo travel values are a good indication of whether you are getting enough servo travel (resolution) or not.
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06-17-2008, 10:21 PM | #8 (permalink) |
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I have not received my unit (Skookum said they are waiting on pc cables or something?). so I am trying to Get The mech. setup ready for when the unit arrives. (hope before the weekend I guess I will Just try as It is, then keep shortening Them To get The correct mix's while Using as much servo Travel as possible?
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
06-18-2008, 08:11 PM | #9 (permalink) |
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Join Date: Oct 2007
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If you use your radio to determine swash percentages, then you will be able to apply them in the SK software and be really close. I think I use +/- 10 for pitch and +/-10 for cyclic. Works fine for my skillz (or lack there of). Also, I use the "swash ring" feature in the SK to prevent over travel / binding with the sticks in the corners.
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06-18-2008, 10:52 PM | #10 (permalink) |
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Tangent = opposite / adjacent
You gotta figure out how much pitch you want (remeber that you need to add cyclic to your collective pitch to find your totals....so like +|- 14 degrees collective and +|-10 degrees cyclic = 24 degrees positive and negative...I work with right angles to make the math easier 24 degrees which is half of your total pitch) So now your adjacent is going to be the distance from the middle of the mainshaft to the middle of your ball. Opposite is going to be the vertical movement required to achieve that pitch. (remeber that we are dealing with half the pitch so its actually twice this, I'm still ignoring this though because we are not done with our right angles.) Tangent of theta times the distance between the middle of your ball link on your blade grip to the center of your mainshaft equals the vertical distance your link will have to move. On a 600 we have a push pull system with boost, so we figure out our boost ratio and incorperate it. We'll ignore that cause 450's don't use boost levers. Now you need to discover how much throw you want on your servo. Lets say 60 degrees total, I'm still only dealing with half the system to keep the math easy so theta (our angle) becomes 30. We use our trig functions again only this time adjacent is our distance from the center of the servo shaft to the middle of your ball link on the servo, and opposite is the vertical distance that we figured out earlier. So opposite divided by the tangent of theta (our angle) will equal the length that our ball should be moved out on the horn from the servo shaft. Using those steps you should be able to figure out whatever you need. Last edited by Dynamic; 06-19-2008 at 06:35 PM.. |
06-19-2008, 12:32 AM | #11 (permalink) |
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Ok, Got more testing done on the Trex. Dynamic, Speedvision thanks for the Info. I realized that I had my original grip ball length was to long. I shortened them to 16mm from Main-shaft center (from 22mm). This made for a much better ratio, I could not get Over 12 degrees of pitch with 22mm offset even with 150% servo movement. I did the mech. setup in my radio and Got 14/-14 col. pitch and 11 Degrees cyclic with the new ratio.
That is with a 55-55-55 swash mix, Servo travels at 110% (can lower to 100% if move swash mix to 58-58-58- which is better?) and no binding that i can see. (Had to Lower my pitch curves because they where around 16/-16) I can now assume that I have enough room to get It set up correctly with that sk360. I will probably Lower my col. pitch to 13/-13 or so. (This Is all On A DX7 radio) Now that I Have that Complex Info from Dynamic (Awesome) I can fine-tune The settings when I refine the head setup, but Think that I am close enough to get It bang on with The electronic setup .?? I also plan on using the electronic cyclic ring to prevent the swash driver (washout arms) from binding in the extreme corners (just slighly), that has been the only problem that I cannot get rid of with the design I am Using. Thought's appreciated....Later
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
07-06-2008, 12:21 PM | #12 (permalink) |
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Join Date: Jun 2006
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bashee biker,
Great design! I've been looking for a simple design to cut down on parts on my flybarless conversion on my 450 as well. I may be trying something like that as well. I'm planing on using the AC-3X on my coversion. I'll stay tuned to see how your design works out for you once you get her airborne. Good luck! |
07-06-2008, 02:37 PM | #13 (permalink) |
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Well, I have been the Flying flybarless T-rex for a week now (around 15-20 flights) and This head setup is working great, I can get my servo travels over 100% and my swash mixes Below 55%. I even Had a crash and It held UP really good, only Took out The blades and one ball link cracked.
I am sold on This SK360- I works Really great
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
07-06-2008, 02:56 PM | #14 (permalink) | |
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Quote:
Here are some pictures of the latest edition
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
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07-15-2008, 04:25 PM | #15 (permalink) | |
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Join Date: Feb 2008
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Quote:
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07-16-2008, 03:01 AM | #16 (permalink) |
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They Are To keep The Head In Phase/ Drive the swash. You can Just use the pins Instead but then You are Unable to adjust your Phasing angle. without Them The Swash Would not remain 90 degrees to the GRIp's and You Would Be Unable to control Your Heli .... = VERY Important, You Can see That I am Still Using One Pin, this it so I can use The stock Phase Angle, I may remove It soon and Try adjusting It a bit.
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Trex 600CF, basically stock, 9252's, Gy611,9256 Api2000 Trex 450 SE v2, JR285mg's, 9257, Beam swash, Neu 1107H/2y + SK360 = No Flybar! Blade CX2, new motors, Tail boom mod + Tons of upgrades R.I.P. Axe cp |
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