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12-08-2008, 08:33 PM | #1 (permalink) | ||||||||
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TREX250 Tail analysis, spacer upgrade and Chinese weights
These are videos of :
I had this tail assembly to design the chinese weights for the T250. But first I had to get the tail assembly to work smoothly enough to do the testing. I am not bashing Align!!! The things that you see in the video are problably not typical. this was probably a bad tail. This video is just to help those who might not know how to diagnose a mechanical problem. These are areas to look at to find causes of excessive drag. Your tail may have none of the issues seen in these videos. TAIL BINDING PART 1
TAIL BINDING PART 2
Comments:
These are videos of:
SPACER UPGRADE & CHINESE WEIGHT PART 1
SPACER UPGRADE & CHINESE WEIGHT PART 2
Comments:
PLEASE DONT PM ME OR INQUIRE IN THIS THREAD UNTIL I POST THAT THEY ARE READY!!!!!! IT MAKES DOUBLE WORK FOR ME TO ANSWER PMS INQUIRING BEFORE I HAVE THEM AVAILABLE. Thanks for your patience in advance, HEIM JOINT Last edited by HEIM JOINT; 12-08-2008 at 09:39 PM.. |
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12-08-2008, 09:39 PM | #2 (permalink) |
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Join Date: Nov 2007
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HEIM JOINT
thanks for all your time and work on this! |
12-08-2008, 10:14 PM | #3 (permalink) |
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Join Date: Dec 2007
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Yup thanks, that looks so cool, add me to that list!
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12-08-2008, 11:52 PM | #5 (permalink) |
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Join Date: Oct 2008
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Heim Joint,
You are undoubtedly The Man! From the time you spend to make these mods, to the time spent in explanation of theory in all you do. You and Finless are top notch examples of knowledge applied in our sport. I commend you for all you do and look forward to future advancements that you will surely take part in. |
12-09-2008, 12:04 AM | #6 (permalink) |
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Can I get on a preoder list? I want these BAAAADDDD. They do wonders on my T450, and t500. TKS MAN!!! YOU ARE GREAT!
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T-Rex 250 super combo T-Rex 450 PRO - I love this little guy! T-Rex 450 SE V2 - Sk360 in Airwolf fuselage T-Rex 500 Blinged to the extreme - Sk360 - Gy401/S9257 - 5045MGs T-Rex 600 LE - KDE everything, waiting on RL53 Raptor 50 eCCPM 140- QuickUk everything - G7703D/S9254 - S9252s - RedLine53 |
12-09-2008, 12:46 AM | #7 (permalink) |
Join Date: Aug 2008
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Awesome job throwing these vids together, let alone the in depth detail you go into.
I was skeptical about the effectiveness of chinese weights on a model this small. You totally blew my theory out of the water. I was wondering if your only reason for placing the bearings in the polarity you chose was to cup the grease (as was explained in the video). It seemed to be that when simulating a load on the bearing (pressing the stack towards the head of the bolt), action seemed smoother with the open end facing the bolt head (which forces the bearings into their races). Do the bearings have polarity or are they just as effective in either orientation? Please put me in the queue for the bearing and chinese weight mods. Again, nice work and thanks for taking the time to put together undisputable evidence of your findings. |
12-09-2008, 12:57 AM | #8 (permalink) |
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Just watched all 4 videos. Very nice work. Really, exceptionally well done.
In one of your other videos, you mentioned it was probably a good idea to keep trivial forces on the servo with any "chinese" weighting, instead of a true zero load. I tend to agree as any servo gear lash, linkage slop, etc would only be felt at the transition from/to 0 pitch (instead of throughout the range). In this video the weights pretty much show zero forces until the end (and may even go negative?). The sheer size of the weights in relation to the grips is pretty amazing. Thanks for the info! |
12-09-2008, 05:28 AM | #9 (permalink) | |
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HEIM JOINT Last edited by Mercuriell; 09-10-2016 at 07:19 PM.. |
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12-09-2008, 10:41 AM | #10 (permalink) |
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Join Date: Aug 2007
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SOB.... I'm sold!!! Great work man and sign me up for a kit when ready!!!!
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12-09-2008, 11:22 AM | #11 (permalink) |
Team Taco VP
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Nice HEIM JOINT! My my hand force testing Saturday the forces were huge! I showed this to many people including Andy. It's almost hard to believe a little servo can handle these forces as they are larger then any other heli I have seen! I could almost not move the slider to full deflection by hand without the control rod bending and twisting the rod guide on the boom!
Can I get a couple of sets of these when they are ready for a review? Bert Kammerer, Andy told me you had made this mod to yours? What was your conclusion? Thanks, Bob
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12-09-2008, 04:15 PM | #12 (permalink) |
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Join Date: May 2005
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I actually got a chance to fly HEIM JOINT's Chinese weights for the 250 along with his tail mod. I have only tried them with the Spartan gyro and several different servos, but so far I haven't been able to tell a difference in flight performance. However, there is absolutely no doubt in the fact that this is a must do mod in order to extend the life of a servo. While testing this with a Futaba 3154, I noticed the servo temps around 120 or so after a 4 minute flight and with the weights, the temp dropped to below 100 degrees!
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12-09-2008, 04:46 PM | #13 (permalink) | |
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Quote:
Plus...I bet without the added resistance you get 100% of the speed rating of a given servo, extracting all the performance from your choice of gyro. |
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12-09-2008, 08:43 PM | #14 (permalink) | |
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HEIM JOINT |
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12-09-2008, 08:48 PM | #15 (permalink) | |
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You will have them as soon as they are ready. From what I experienced you will need new (not Align) blade grip bearings to get rid of the problem. The spacer upgrade alone did not change it until I put new bearings in. Thanks for all your help Robin |
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12-10-2008, 01:50 AM | #16 (permalink) |
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Join Date: May 2007
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Agreed, the Align 1.2mm bearings are pretty crappy. You'll probably push the inner race right out of the bearings while preloading. I did my own version of Heim's preload with better bearings, and the results were spectacular. I can't "wait for the weights." Align's new tail hub mod with the single 2mm bearing isn't going to do you a favor if you want the Chinese weights. Those weights will put too much side (lateral) load on that bearing, given the centripetal force pulling on them at high throttle. It's gonna take a good set of 1.2mm bearings with a proper preload to handle the lateral load. It's all going to be worth it in the end. Neall
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12-10-2008, 11:05 AM | #18 (permalink) |
Team Taco VP
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Heim Joint, been thinking about this on the T250. I think it might be better to tune the weights so there is some tennis racket effect trying to return the slider to center. Reason I say that is slop. By having some return force this "takes up" the slop that is in the slider. Of course when you transition from left to right it will slop over and take up the slop the other direction. But with ot without the mod this will be the case anyway.
With 0 force then the tail as the ability to always slop back and forth in any position and thus the servo is wagging trying to compensate and take up the slop. All my align helis the design has some inherent slop in the slider. On larger helis the proportions are enough that the slop doesn't seem to cause issue. But when they scaled down the 250 the didn't scale down the part tolerances (and probably couldn't or it would be too expensive) so now in proportion the slop is too much for this little tail and the control resolution. So having a small amount of back force may help keep this slop taken up. Get the idea? Bob
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12-10-2008, 11:57 AM | #19 (permalink) | |
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I understand completely and I will check it out on the next tuning run. My initial guess is the tuning that would give a pushrod force that will actualy gently push back to 0 pitch from either side would be relatively high. probably 5-6 oz. on the T250. You can see if there is a performance difference by comparing the batman blade to the straight blade on the T250 with the Chinese weights on. The straight blade is wider and has about 5 oz, pushrod force using the weights that were tuned for the batman blades. If the tail seems more precise with the straight blade then that would support your point. You would need to separate more "authority feel" from more "precise feel" because the straight blade has more area. I would think that if this was a large issue you would see a "micro wag" in a hover from the gyro/servo fighting the play in the control system. Robin Last edited by HEIM JOINT; 12-10-2008 at 03:23 PM.. |
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