Blade SR Tail Rotor Motor Life Extension
As many of you know the tail rotor motor life isn't long, but I may have found solution.
The stock SR has the tail motor mounted on the right side, and everyone reports it makes that high pitched scream which I think is the motor RPM going beyond the design RPM of the motor, so for fun I have been working on installing the Huey body, but first I wanted to see how it flew with the raised tail rotor mounted on the opposite side, I was amazed to find that the motor rpm dropped so much that you can't hear it and that the motor temperature was only warm after about 15 mins of hovering, unlike my other motors that had temperatures 135 degrees F +, could burn you if you touched them.
So for a summary, either the motor I have is a really good motor, or mounting the motor on the opposite provides a dramatic improvement on the motor operation. If you do this remember to reverse the wires.
I am going to try and install another motor that always heated up to see if it is the motor or not.
let us know the results, I am curious to say the least............. also thanks for all of your tips ! ..... haven't had to use any yet, but "info" is always good !! - especially with the appalling parts support that "Horizon" has provided - there must be A LOT of these on shelves waiting for parts, which is sad for the beginners wanting to "get going" and learn........
keep it up,
With the motor mounted on the right side, the the tail rotor air flow is to the right, leaving the motor when hovering with little air flow over the motor housing, mounting the motor on the left (the motor has to be wired to spin in the opposite direction) will now force air flow over the motor housing which seems to be enough to help keep it cool.
To test this out I am going to use the same motor wired the correct way and mounted on the right side to see if it heats up like the other motors, should have the tests done later this weekend.
I was going through tail rotor motors about every two flights. You and I apparently were both thinking alike as I had entertained the same thoughts about reversing the tail rotor position to resolve the motor burning-up issue, hoewever I wasn't sure what the total impacts might be.
Originally Posted by NXT LEGO
So before trying it I went to the store where I bought the SR and I proposed the configuration as a possible solution with the store owner. He was concerned that by reversing the tail rotor side I was proposing might throw the tail rotor control timings off.
I went back home and spent a couple days (while waiting for new tail-rotor motors to be sent) putting more thought into what I was thinking to try. Specifically I explored a little further in terms of how the controler and gyro coordinate their combined functions to control the tail-rotor motor.
Not having any technical documentation about how the controller board / gyro worked I thought I could at least reason this all through to determine if such a bad impact to tail-rotor controller may happen.
I reasoned the following things through:
1. The controller board's reacting to the gyro signals would have to be based upon some mathematical bell-shaped curve.
2. The controller would produce outputs based on the positive-value side of the bell shaped curve when the rotor is in it stock position coming from the factory.
3. Polarity somehow had to play into the input's equation values underpinning the controller board outputs.
4. Reversing the physical tail rotor location from its stock position would now use the negative-value side of the bell-shaped curve to produce outputs.
5. Reversing the electrical polarity so the directional spin of the tail rotor blade remains to be counter-clockwise, the controller-board output value results would be converted to positive values since the polarity reversal would negate the negative input values from the controllers use of the negative side of the bell-shaped curve.
6. In theory then the controller- board output values will be exactly the same no matter either position the tail-rotor is oriented to.
I concluded from all this that there should be absolutely no timing concerns then and that the tail rotor should react fine AND that the life of the motor now may last much longer and without burning up since there would now be direct air-flow over both the tail-rotor motor and the heat-sink extractor that sits on top the tail-rotor motor.
So I went ahead and did the modifications and have been flying the SR ever since with the same tail-rotor motor. When running the SR with this configuration I too noticed that:
1. The high-pitched tail-rotor motor squeel completely went away.
2. The rotor spins relatively slower.
3. The frequency of having to spin has been noticeably reduced.
4. The rotor motor temperature from the run has been significantly reduced.
5. The SR is relatively more stable in this configuration upon main rotor startup and when in flight.
I have made at least 20 flights using this new configuration and I believe it to be a proven solution to the issue.
I discussed again with the store folks this configuration in terms of that in theory and what is physically done, there are NO perceivable timing issues or concerns. As we discussed my conclusions the store owner called the Blade technician and the store owner and I both discussed the solution configuration with the technician.
The store owner stated to the Blade technician that he had witnessed other manufacturers place the tail-rotor of their choppers to the opposite side of the tail boom from that of the SR and that it was perfectly acceptable to do so.
I was asked by the technician to identify everything I did to effect the new orientation of the tail rotor motor. I said the only critical-path modifications were (1) relocating the plasitic tail fin, (2) drilling a new rotor motor's indexing hole to the opposite side of the tail boom and (3) soldering the wires for reverse polarity. I said overall it took a total of about ten minutes to do.
The technician indicated he was going to seriously check into this as a possible configuration solution to the issue they are aware the users of the SR are having.
I did walk away from the telephone discussion that the Blade technician was genuinely interested in what was being discussed. It will now be interesting to see IF/WHEN/HOW the makers of the Blade SR are going to use all this information.
Last edited by RCKindaGuy; 06-13-2010 at 03:28 PM.
Thanks for taking the time to share the info ( and spending the time on it ) !!
I haven't encountered this problem, but will try out the suggestions - i use it for practice in the back yard so it's not really getting a "good" workout - that's probably why I haven't had a failure....... although when I ordered spare parts - the tail motor was in the list - so far it's taken about 2 months to get 3 parts - that's at Horizon, not the LHS
( I looked at what the others were breaking most often, and ordered those parts )
I had performed an Internet search and found that only 1 of 5 web-site vendors came up in the search as having the tail-rotor motors in stock. Everybody has been backed ordered for weeks. However the local shop where I bought the SR told me they were to receive a shipment of motors in that following week. When they finally did come in I bought the entire stock that arrived (5 of them) which cost me about $53.00 total. I used 1 of those 5 motors in the solution I spoke of and it hasn't burned out yet. Now I have 4 extra motors that will probably last me a good long while since the solution definitely extends the longevity of a motor quite alot.
Originally Posted by Warren
Last edited by RCKindaGuy; 06-13-2010 at 03:30 PM.
I am really happy to hear that someone else has also experienced good results from my earlier observations and mod, and has gone as far as contacting Horizon, way to go.
I have also discovered another interesting fact on the tail rotor, from day one the motor would heat up excessively as I pointed out earlier, but after reading the Huey rotor installation instructions it clearly stated you had to make sure you install the tail rotor blade the correct way, but there was no picture or diagram showing which way was correct. I contacted Horizon and asked which way the tail rotor should be installed, and to my amazement I was told either way, this makes no sense because the blade edge is significantly different from one side to the other, I did some experiments and discovered that one way the motor will over speed and over heat, while installing it the other way it slows down and stays cool. I have only tried this with the tail rotor motor on the left side, so I imagine the same should hold true with the motor on the right but the motor is still sitting in still air.
Discount Hobbies had good supply of motors along with a number of other SR parts.
For those of you thinking of moving up from the SR, I have moved onto the Blade 400, been successful in hovering and the from the SR to the 400 is fairly smooth using the Tamed 400 radio settings from Horizon.
In regards to installing the SR tail rotor blade correctly - I found that the side of the hub on the rotor blade that is touching the washer of the hex screw has an almost imperceptable raised circular edge that in essence fits comfortably in the semi-beveled wear-spot on the inner surface of the hex screw's washer. When I had mounted the tail blade with the raised edge to face the boom the tail rotor hub shatters from the torque. I went through 4 tail rotor blades in 10 minutes without getting one flight out of it because I mounted the tail rotor blade with that raised hub edge facing inward toward the boom.
Originally Posted by NXT LEGO
OK I am responding to my own post quote here because I want to retain the record of the entire conversation. I am going to disagree with my quote here as further experimentation has proven otherwise in regard to which edge of the tail rotor propeller is the correct leading edge and what causes the shatterig of the rear rotor propeller. One would think that the edge that should lead in the counter-clockwise movement of the tail rotor blade should be that edge which presents itself as the longest edge. However as NXT LEGO reported and despite the absolute WRONG response given by Horizon to NXT LEGO, there indeed is a very significant difference between the two edge sides in terms of their twist-torque design.
Originally Posted by RCKindaGuy
Upon further flying I now discovered that having the wrong edge of the tail rotor propeller as the leading edge to the counter-clockwise tail-rotor movement will cause two things to happen:
1. It sigmificantly raises the torque on the tail rotor propeller to the point that the tail rotor will usually shatter.
2. If the rear tail rotor manages to survive #1 without shattering, the chopper will immediately begin to chase its tail when the chopper lifts off the ground no matter how you trim to counter it OR no matter how much rudder stick used to try to counter it.
I originally believed that the correct edge of the tail rotor would be the longest edge of the the two tail rotor edges. So when doing this I have found either #1 OR #2 WILL happen. However as NXT LEGO pointed out, the wrong edge used to lead will cause the tail rotor motor to significantly overheat (again) and burn it out. And this is despite having made the switch of the entire tail rotor assembly from boom-right to boom-left. [Please NOTE here the relocation of the entire tail assembly from boom-right to boom-left is still necessary if you want to stop the original overheating issue of the tail rotor motor. The issue NXT LEGO and I are both speaking to now is an entirely new issue causing tail rotor motor overheating.]
Back to this issue.....After having read what NXT LEGO discovered I made an "eyeball" examination of the tail rotor propellar and found exactly as NXT LEGO pointed out...looking at the propeller with its shorter edge being closest to my eye I could see a significant amount of edge twist coming off from the central hub of the tail rotor propellar...whereas when looking at the tail rotor propeller with its longest edge being closest to my eye I could see a rather flattened amount of edge twist coming off the central hub of the tail rotor propeller. This extreme twist differential between the two tail rotor propeller edges greatly impacts the tail rotor's function for countering the torque produced by the main blade to keep the tail aligned in the direction of the front of the chopper.
So I went ahead and reversed just the tail rotor propeller on its mount axle so the most aggressive edge twist from the hub would be the leading edge to the tail rotors counter-clockwise movement. Flying the SR after doing this, the SR STOPPED chasing its tail and flew extremely stable without the tail rotor motor overheating. So in conclusion to this issue one has to really examine the tail rotor propeller edges when changing out the tail rotor propeller on these SR's to make sure that the propeller edge having the most aggressive looking torque twist coming off the propeller hub is placed as the leading propeller edge to the counter-clockwise tail rotor movement.
Because there has been such a complete and throrough demonstration of total design ignorance on the part of Horizon regarding the overall tail rotor assembly design, it would NOT surprise me if they inconsistentently manufacture the tail rotor propeller with the little "raised" hub area in both manners with it either being potentially on either hub side of the tail rotor propeller. In light of this, I hesitate now to even suggest as I did previously that the "raised" area on the hub is the marker for denoting the correct edge to act as lead. And I further hesitate to think that the "raised" hub area I talked about in a previous post would always coincide with the longest tail rotor propeller edge leading the counter-clockwise movement of the tail rotor.
In short as NXT LEGO speaks to, one has to really examine and eyeball each tail-rotor blade to determine the correct way to mount it to the overall tail rotor assembly.
Last edited by RCKindaGuy; 07-11-2010 at 08:05 AM.
Been a while since I have made comments on the SR, I have upgrade to the Blade 400 which is lots of fun, but have now gone back to the SR for a bit, which was an interesting transition, really shows how fair you can move the sticks on the SR vs the Blade, night and day. Anyhow found this new tip below that might help break in the tail rotor motor, posted at http://helifreak.com/showthread.php?t=202973.
17. Gently break-in your tail motor before first flight. Hook up a pair of D-cells in series and let it run without the tail prop attached for about 20 minutes. This seats the brushes, extends tail motor life, and reduces long-term wear.
I have also purchased one the electronic temp meters so I can now actually do some real tests on the motor temperatures. It seems that Horizon has not had many good reviews on the tail rotor motor. http://www.horizonhobby.com/Products...322#reviewsTab