View Full Version : tail special ball links
In the Intrepid gas instruction manual (page 80) it says to "trim the rib from the tail special ball links, and cut 1/8th inch off of the end." I followed the instructions exactly as it states; however, now with the blades set at zero pitch the slider is not centered on the output shaft (as Gary Travis's video states it should be) because the special ball links are too short now. Also, I can see on Gary's video that his special ball links were not shortened. Should I not have shortened the ball links as per the instructions?
cbergen
09-24-2006, 12:43 PM
http://www.helifreak.com/viewtopic.php?t=19351
Chris, that set-up page doesn't help. What I'm trying to say is that when I set my tail blade grips at zero pitch (just like the bottom right photo on page 80) my slider is way off center: 5mm deflection to the right and 15mm to the left (toward the boom). Now I also notice in the photos that the tail output shaft protrudes through the end of the tail blade grip assembly. Mine does not. In fact, it's about 1/16th inch inside the blade grip assembly. And yes, the setscrew is perfectly inserted in the dimple at the end of the tail output shaft. Something is wrong!!! Looking down from the top, as in the lower right-hand photo on page 80 of the instruction manual, with my blade grips pointed up like the photo (zero pitch), I'm off center like I explained above. If in fact the blade grip assembly slid on the output shaft further, and the special ball links were not shortened, then the slider would probably be centered. Please advise.
Greg Alderman
09-24-2006, 01:48 PM
Bobs....as Chris shows in the PDF when the pitch slider is centered you don't want "Zero" pitch on the blades...you want what ever pitch is needed to keep the tail from drifting in a hover with the gyro set on Normal (rate) Mode...
if you point both tail blades "up" start with about 15mm spacing with the fwd blade pointing towards the tail boom...
Greg, all I'm doing is going by the book: that is, the instruction manual and the photos therein. Also, I'm following Gary Travis's video on setup which states, and I quote, "back here you want these blades to be at zero pitch and your tail rotor hub, the slider, right in the mid shaft position. In other words, half way out of your output shaft." His video shows the tail blades at exactly zero pitch with the slider centered. Who should I listen to, Gary Travis or you? As I'm trying to explain, that is not what I have. In fact, far from it. As I indicated in my last post, I have a couple of things that are not the same as in the photos in the Bergen instruction manual, not to mention Gary's video. Once again I say, something is not right.
Greg, one last point. I've built three Raptors. Upon checking them I found that when the tail blades are at zero pitch the sliders are centered.
MarkWebber
09-24-2006, 07:21 PM
I've just gone and looked at mine and it has maybe 5 degrees at center on the slider. Like Greg noted, you're going to want to center the slider with what ever pitch your heli needs to hold the tail straight. That worked out pretty much dead on when I followed the manual on my Intrepid EB for trimming the links.
And you'll find when you get it in the air...it ain't no Raptor :wink:
PaulH
09-24-2006, 07:26 PM
This sounds like a conversation I had with Chris two weeks ago. There are actually two distinct versions of the tail blade grips. Look at the location where the Pivot Plate Eyelet screws into the blade grip. If this "ear" is in the same plane as the blades, then you have the older style grip. If the "ear" is offset to the outside of the tail blade rotor disc, then you have the newer style.
In order to hover with the tail pitch slider in the center of the output shaft, the old grips require the "special" ball links to be shortened so much that there was nothing left for the screw to grip.
Bergen R/C introduced the new style grips with a built-in offset. A further improvement is that the ball link screw on the eyelet is a larger diameter and will work with the normal Rocket City style links. The links will need to be shortened to 17 mm (I think? Don't have the manual in front of me ATM) per the manual.
BINGO. Paul, you nailed it on the head. I do have the "new style". I can see in the instruction manual photos that they're the old style. So the bottom line is that the links should not have been shortened; however, the manual is not updated to include this information, not even an addendum sheet for corrections. The links not being shortened an eighth of an inch will help to center the slider but I still think there's an issue with the tail output shaft not protruding through the end of the blade grip assembly. If the shaft went through the end of the blade grip assembly that would give me approximately another eighth of an inch, maybe a little more, and then the slider would be centered perfectly. Now I know why the links in Gary's video weren't shortened.
PaulH
09-24-2006, 08:50 PM
Download the PDF that Chris linked to in the second post. Look carefully at the last two pages. You'll see a couple good close-up pictures of the tail. The grips shown in the pictures are the "new" style. You can get an idea of how long the ball links need to be.
In one of the older versions of the manual the total length of the plastic length was specified to be 18 mm. I trimmed a pair of Rocket City links to 18 mm and used them. After centering the pitch slider on the output shaft I think I needed 1/2 turn out on both of those links and my tail was dialed in.
Thanks, Paul. I'll have to contact Chris tomorrow and try to explain this to him. The stock links would have been perfect but the manual said to cut them down an eighth inch and, unfortunately, I followed the directions to a "T". But there's still the issue with the length of the shaft. Actually what I think is wrong there is that the dimple in the shaft for the set-sccrew is placed too far out on the shaft. By the way, I did loosen the links as much as I could but it's still not enough to center the slider. With the original links loosened up a little bit I probably could have centered the slider, though. Thanks again.
PaulH
09-24-2006, 10:16 PM
Just for kicks, see if a pair of the normal Rocket City links will work. Like I said, the screws are larger in diameter than those used on the old-style grips. You will need to cut them down a little, but it's worth a shot.
The plastic links used on the old-style grips are actually the same size as the longer links used by Align on the Trex 450.
cbergen
09-24-2006, 11:18 PM
Bob,
Read through the PDF link posted. Set your tail up EXACTLY as it states. Just so I'm clear here, DO NOT do what Gary shows in the video, do not try to follow the instructions in the manual, and for right now DO NOT worry about having cut the links.
If you are not quite to the point yet of even turning on the radio, then wait to setup the tail until you are ready for the radio gear.
If, AFTER you have setup the tail per the PDF link, it is determined that the links are too short, then I will send you a brand new set.
Now before anyone gets all silly about it, Gary's video is not wrong, it's just another way of doing it and works just fine.
Chris, I've read through the PDF link a couple different times. Whether the radio is on or off, servo and tail rod connected or not, the point is that I am unable to manually duplicate figure three in the PDF. I have even loosened up the links so that they're only holding on by a couple threads, if that, and still I'm not centered like figure three shows. If I hadn't cut the links then the slider would be a lot closer to centered. If I can't even duplicate figure three, what's the point in continuing any further? Again, my slider is not centered when set up like the photo in figure three of the PDF. Quite frankly, this is a hell of a time to tell me NOT to follow the instruction manual and NOT to follow Gary Travis's video. I NEED ANOTHER SET OF LINKS, period, for a starter. And I still haven't heard any comments about the output shaft issue. Now, I appreciate the help but have to admit that I'm concerned about being told to basically ignore the manual and Gary's video. As you know, there are NUMEROUS dicrepancies in the manual. Maybe if you read all the above posts again it will help you understand what I'm trying to explain. I'm not going to start adjusting servos, gyros and tail rods until this thing is set up properly manually first. That would be like putting the horse before the cart. If I'm starting to sound annoyed it's because I am.
Check out my gallery. I just took three photos to help explain what I've been talking about. Please pay particular attention to the one where the output shaft is recessed in the blade grip assembly. Also note that I have loosened the links up as much as possible in order to get the slider centered, and yet it is still not in the center of the shaft. Should have done this sooner: a picture is worth a thousand words.
PaulH
09-25-2006, 09:12 AM
Chill out Bob. Four people, including myself, have given you all of the information that you need. I followed it two weeks ago when completely rebuilding a tail gear box and it worked. Verbally lambasting Chris for discrepancies is not helping.
Gary made his original video based on an older version of the tail blade grips. Of course he'll have a different way of setting them up! The parts have evolved since the video was made. The manual isn't 100% up-to-date, but the PDF file that Chris linked to in the second post is correct.
Have you even tried a set of the Rocket City links? Seriously, they do work. It would take you all of ten minutes to verify this and could very well solve your problem. The tail blades will have four or five degrees of pitch with the slider in the center of the output shaft. This is what keeps the tail from moving in a hover.
Get everything connected, power up your radio, put the gyro in rate mode, then use the long pushrod to center the pitch slider. Go hover the bird. If it wants to piro in rate mode, use the small tail grip links to adjust the hovering pitch on the blades.
lperagallo
09-25-2006, 09:50 AM
Bobs,
After looking at the pictures you posted, I'd say you have a tail shaft to blade grip issue. The shaft should go through the blade grips and extend a bit at the the end. This is probably the cause of your issue with the links. If you had continued your build and added the bellcrank, you would have seen that you have bigger issues because you won't get the throw you need with your tail shaft not positioned correctly. Looks like you will have to call Chris and ask nicely if he'd look at your gallery and explain if the tail shaft is bad.
I also agree with PaulH that you should calm down a bit and not be blasting away at Chris. I see in your gallery you have Raptors. Have you ever tried to call the manufacturer to get support for your Raptor. I'm sure you won't get much if any. I know when I have a question with my Raptor I have to go to the web. When I have a question about my Bergen, I call Chris. After I built my bird I went to a FunFly where Chris was and he spent 6 hours with me helping me set it up correctly. He worked with me and made small adjustments until it flew great. Try to get that kind of support from any other manufacturer out there.
cbergen
09-25-2006, 10:03 AM
Bob,
In order to get the tail setup properly, you have to START at the radio gear, not the mechanics.
Your pitch slider will NOT, I repeat, NOT be centered with the tail blades straight up and down.
Figure 3 is showing the fact that the pitch slider is centered, nothing else, shall I quote? "Looking at the tail pitch slider, it should be centered by adjusting the length of the carbon fiber pushrod (figure 3)." It is NOT telling you to set the tail blades straight up and down!!
The carbon fiber pushrod is the LOOONG black thing from the servo to the gold bellcrank. This is what you adjust to center the tail pitch slider.
I believe you may be reading or seeing too much ahead of where you are now. If you go step by step by step, it will work itself out.
Paul, I have no Rocket City links to try. I'd have to order them because there are no hobby shops in my area. Getting a new set from Chris will be just as expedient. I don't mean to "lambast" Chris, but the instruction manual does need extensive updating. At this point I'm too frustrated to continue the discussion. I believe the photos explain my position completely. New links will be a starting point; however, I still need to hear from Chris about the output shaft situation. I do appreciate your comments, though.
cbergen
09-25-2006, 10:13 AM
On the subject of the "divot" in the tail output shaft. The divot is in the same spot, the shaft may have been cut off a little more than necessary.
My Turbine is the same, and has been flying that way for the whole flying season. It will not pose any issues.
cbergen
09-25-2006, 10:16 AM
I have looked at your photos, and what you are trying to achieve is totally unnecessary, and will not end up that way once you do the tail setup as outlined in the PDF that paul put together as the most recent update and how to tip.
Thanks, Chris. That's what I wanted to hear. The shaft thing was really bugging me. Just for my own peace of mind, though, I'd still like to start off with a new pair of links that haven't been shortened. I'll give Mary a call this morning and order them. And hey, even though I do have some issues with the instruction manual, your customer service is beyond reproach. Thank you for sticking with this issue and setting my mind at ease. If this bird flies half as good as the service/attention I've received, I'll be thrilled, to say the least.