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11-24-2008, 08:52 PM | #1 (permalink) | ||||||
Team Taco VP
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Review - Heim Joint's "Tennis Racket Effect" mod for helis
OK as you all know way back Kevin (Fireup) decided to do a Chinese wight mod for the Trex 450. This helps keep the tail servo from working too hard. All up, I would never fly a 450 without the mod. YES it's that much better!
So Helifreak user Heim Joint went the extra mile and and with testing to the "NATS ARSE" level came up with a screw on device that works prefect and is easy to apply. Here is his testing videos on YouTube: Trex500:
Trex600:
OK so he sent me some to try. LOVED THEM on my Trex500 with Kasama tail grips! In this review because Heim Joint sent me a few other like for the STOCK Trex500 tail I let others try them. Here is my review: Video Link ->Heim Joint's Tail Weight Mod (17 Megs) In the end this is a good product. I think heli manufacturers should start doing this in the design. Bob
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11-25-2008, 07:36 AM | #2 (permalink) |
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Whoa! Those are some pretty compelling demonstrations!
First off, Heim Joint that was great! I can't believe I was staring so intently at someone sliding a force gauge, but damn, I was! I've been following the C.W.M. threads on the forum since they started, and lots of folks have done some good work researching, experimenting, and developing. (Fireup's jig has been sweet). But this does a great job of quantifying the problem and a solution. Of course it leads to some questions! HJ mentioned that at the extremes he though the forces he measured with the CWM were actually aerodynamic. Is the mod taking out aerodynamic forces at smaller pitch angles? Or is the pivot axis of the tail rotor along the center of lift so that there aren't any aerodynamic forces at smaller angles? Or is it a cosine thing at smaller angles? Just curious as taking out too much of the aero forces could result in funny gyro performance between really hot and cold days. (i.e. tail goes from self centering or neutral to anti centering as it does with CWM without blades) This also begs for some on-heli tests investigating what we think we know about tail servo size and tail performance. Is it time to fly 450's with micros on the tail? How 'bout a 600 with a 9257? All with no loss, or even an increase, in performance? I'll leave the "OMG THIS IS AWESOME WHERE CAN I GET IT????!!" questions to others. ....... The hell I will, THIS IS AWESOME WHERE CAN I GET IT?? Erik |
11-25-2008, 02:00 PM | #3 (permalink) | |
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Quote:
The Trex 500 chinese weights are $16.50 a set plus $2.00 shipping & handling for up to 2 sets in USA (US postal letter) I need: what type (kasama, Align metal or stock plastic) quantity, your name & shipping address email address to send you a paypal invoice that can be paid with credit, debit, or paypal. The Trex 600 chinese weights (nuts only) for stock plastic grips are $7.50 a set plus $2.00 shipping & handling for up to 2 sets in USA (US postal letter) Thanks for your interest. HEIM JOINT |
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11-25-2008, 05:32 PM | #4 (permalink) |
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Hello Heim Joint,
and what do you think of these ? : http://flying-hobby.com/catalog/prod...oducts_id=2860 Can I use the mod for Kasama? and do You send to europe? Z
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| mCPX BL@DX6i | Trex700N-LE@BX | TDR@BX || FunJet 2W20@4S | SwiffieII || FF10 || 720i DUO3 | ALC8500 |
11-25-2008, 06:25 PM | #5 (permalink) | |
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Join Date: Feb 2008
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11-26-2008, 06:46 PM | #8 (permalink) |
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yep, to both questions ?
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| mCPX BL@DX6i | Trex700N-LE@BX | TDR@BX || FunJet 2W20@4S | SwiffieII || FF10 || 720i DUO3 | ALC8500 |
11-28-2008, 03:38 PM | #9 (permalink) |
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PM sent to Heim
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| mCPX BL@DX6i | Trex700N-LE@BX | TDR@BX || FunJet 2W20@4S | SwiffieII || FF10 || 720i DUO3 | ALC8500 |
11-29-2008, 09:34 PM | #10 (permalink) |
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Tried my set out:thumbup:
I got to try a set that Bob got for the Trex 500 Kasama grips as well. Like Bob I previously used a longer bolt with extra nuts on the ends to help with the "tennis racket effect".
Heim Joint's Trex 500 chinese weights worked very well for me. I had to turn the gain down about 4%, but after that it held very steady. It even felt easier to turn my tail around. I think it is a perfect match for the Kasama grips I have. |
12-02-2008, 08:41 AM | #12 (permalink) |
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Join Date: Oct 2008
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This is probably a silly question.
Would this type of mod benifit basic flight, most people strive to do extreem 3D and I could see that there would certainly be benifits in 3D I am pretty new to all this and I'm like most blokes - want the latest gadget for their toy. But in the real world if it has no real benifit to a novice, money would be better spent elsewhere ... like a spare set of rotor blades or carton of beer Troy
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12-02-2008, 09:35 AM | #13 (permalink) | |
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12-02-2008, 10:45 PM | #14 (permalink) |
Join Date: May 2008
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Just sent a PM, hope to get a set soon. I can see how servo manufactures may be shaking in their boots with results like this. We've all come to learn that bigger is better, and now it turns out that this is not true for tail servos anymore as long as the grips are balanced correctly. I wonder if this is why the the kit makers have yet to really incorporate these relatively simple mods into their grips.
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12-03-2008, 10:49 AM | #15 (permalink) |
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Join Date: Dec 2006
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Are you planing on doing it for any other heli? For example for a T-rex 450 and/or Vibe 50?
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12-03-2008, 11:35 AM | #16 (permalink) |
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Bob, I have a question for you.
Based on the evidence presented it seems obvious that the mod works and works very well. So the question is, with this mod being fairly commonplace on the net for at least a year, why do you think none of the latest released helis have implemented this design yet?
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12-03-2008, 12:05 PM | #18 (permalink) |
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Faster tail servos are possible now
Bob,
With the pushrod forces now being so very low using my precision Chinese weights. Servo manufacturers could easily decrese their speed by at least half. Take a hitec 5083MG at 20.85 oz.in and .07 sec/60 speed. They could just change gearing only by a factor of 2 and have 10.4 oz.in and .035 sec./60 speed. in the same servo. With a .5 ball distance on the servo arm that would give 21 oz. pushod force when the max. needed is 2 - 4 oz. thats at least a 2.5 : 1 safety margin. This could be just a gear set available for those running precision chinese weights. Do you know anybody in the servo business to approach about this? Thanks for all your help, HEIM JOINT |
12-03-2008, 12:29 PM | #19 (permalink) |
Team Taco VP
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Honestly no I sure don't and I don't think this will be noticed that much by them until more and more helis start doing it in the design thus the SPECS needed for the heli cause the change. Just my thoughts on how this would roll out long term.
Bob
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"Don't Taco My Pack Dude!" NEW Video Link -> Safety Video #1 Video Link -> CAUTION using powerful tools! Video Link -> How to CRASH TWICE in one flight! Video Link -> Don't Taco! |
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