View Full Version : gear mesh
How much backlash, if any, does everyone have in their pinion to main gear mesh? Just for clarification, I have a new Intrepid gasser (non EB) with a little over a gallon of fuel through it. Initially, on my first flights, I had zero backlash; however, I now have developed some minimal slop between the gears. I have tried to remove this slop but am unable to at this point due to the inability of the motor to move rearward any further. Just curious if this is normal with everyone elses set up. Thanks.
cbergen
12-04-2006, 04:51 PM
If you have a standard gasser, you should still have plenty of room to move rearward to take up any backlash.
Loosen all four bolts that attach the pull start adapter to the frames. REMOVE the 2 ea 4mm bolts that go directly into the engine crankcase. Loosen the four bolts that go into the triple bearing block.
Adjust your mesh as necessary. Tighten the 4 triple bearing block bolts, tighten the 4 pull start adapter bolts, THEN install the 2 ea 4mm bolts.
be sure to loctite the 4 bolts in the triple bearing block and the 2 ea 4mm bolts in the crankcase.
Chris, I do have the standard gasser but not only don't I have "plenty of room to move rearward" at this time, I never did have any lateral movement to speak of from the beginning. As you know, the four motor mount holes in the frame are slotted to have movement up and down; however, there are no slots (adjustment) for lateral movement. The slots in the bottom of the frame where the pull start attaches does allow for forward and aft movement, however, the four holes in the frame which line up directly to the holes in the motor DO NOT allow for any movement back and forth. And yes, there are slots in the triple bearing block to move it forwards and back, but if I move the bearing block closer to the main shaft then the alignment is not straight. Now, if there were slots in the frame to accommodate lateral movement, or if the holes were, perhaps, enlarged, then I could move the motor fore and aft a small amount. Perhaps I was supposed to enlarge the holes in the frame or ream additional lateral slots in the holes to accommodate room for adjustment? It all boils down to this: how can the motor move fore and aft when the four holes - two in the frame that go directly into the engine and two in the rear of the frame that go directly into the motor mount bracket - are sized to line up perfectly with the each other so that the bolt can be inserted through the frame and into the motor and motor mount bracket? The extremely small amount of fore and aft adjustment I might have had initially is no longer present. I was merely curious how much slop other Bergen oweners have in their setups.
I've had to slot the 2 motor mount holes in the side frame in order to get the required backlash. I also had to slot the holes in the frames that attach the head bar. The correct backlash has always been a challenge to get right (for me anyway). In saying that I have always managed to do it though.
Thanks, Gyan. Yeah, it just gets frustrating trying to accomplish zero backlash with the stock design: in my opinion, it's impossible. It's good to know I'm not the only one having this problem. Thanks again.
cbergen
12-04-2006, 10:06 PM
I guess you just have to trust me on this. Don't analyze it, just do it per the instructions I wrote.
The engine WILL, I repeat, WILL move rearward. The slots in the pull start adapter will allow it.
If you must, analyze it this way. All of these exact same components are used in the EB version. The only differnece is a 12 tooth pinion, which is SMALLER than the 14 tooth pinion, and requires the engine to move EVEN FARTHER BACK then what you are trying to acheive.
The reason you may be having trouble moving the engine is that the frames are squeezing the pull start adapter making it difficult to move. But believe me, it does move.
The vertical slots for the 4 mm bolts are of sufficient width to allow the small movement sideways needed to obtain proper mesh. It just makes the process easier if you REMOVE them when making an adjustment.
This individual had the same problem. http://www.rchelispot.com/viewtopic.php?t=6759 Although he doesn't spell it out in this thread, (He chose to call and discuss it first) this is the difficulty he alludes to when he says " talking my thick headed self through the pinion swap on the EB and setup etc"
Gyan, do you actually have zero backlash in the pinion and main gear mesh or is there still a small amount of movement (slop)? I have followed Chris' instructions twice now and am unable to remove the backlash completely. The only way I can accomplish "zero" backlash is if I loosen the four triple bearing block bolts and push the start shaft and pinion towards the main gear; however, that naturally causes the the start shaft and main shaft to be out of alignment. I would still like to hear from other owners if they have accomplished "zero" backlash without modifying the frame holes. If everyone has a small amount of slop in the gear mesh, then all is fine. My understanding, though, is that we're supposed to have no slop. Thanks.
I like to have a slight amount of play, not much mind you. With the gears aligned properly there is alot of contact, & no way will it strip inflight, of course all bets are off when the blades meet terra firma. If there is a little play it reduces friction between the gears.
Thanks, Gyan. Maybe a few others will read this and post their experience with gear mesh results.
Gary Travis
12-05-2006, 09:56 AM
I have set up countless Bergens and have not to date had gear mesh issues, as Chris has stated the pullstart adaptor plate is slotted to allow forward and backward movement. How I do it is as follows after loosening the four bolts going through the frames at the base of the engine and the bolts securing the bearing block I rotate the main gear until I find the spot on the gear that seems to be the lowest. As with all delrin gears you can have a high spot in the gaer itself. When I find the low spot I tighten the mounting bolts for all.
Now when doing this you may fell a tight spot in the gear mesh, not to worry! At this point I will take the helicopter out and set it on the ground. Let it spool up and run without leaving the ground, I do this for several minutes, this will wear in the high spot that may be present. After several minutes of this you will notice that the gear mesh will be much smoother, at this point I check the mesh and readjust as needed. I have seen some set the mesh at the high spot of the gear and then end up with to much play as the gear wears in. Also I would agree with Chris that it is not something that should be over analized. PM me if you need any assistance in this.
Gary
Oh ya Gary's right a slight adjustment after a run is sometimes required with a new gear. :wink:
Gary, I'll try it once more, but just to make sure I'm doing it correctly, should I also be removing the two bolts that go into the motor mount bracket underneath the spark plug? That's the way I've done it on two previous tries. And am I actually looking for "zero" backlash? Thanks.
Gary Travis
12-05-2006, 11:37 PM
Won't hurt to losse them.
Gary
Gary Travis
12-12-2006, 10:10 AM
Make sure you don't get it too tight, a friend of mine here in UT has just ordered an EB and will be building as soon as it arrives, I will see if he has any problems understanding the gear mesh setting as per the manual. To date everyone I know has been able to get the mesh wright by the manual. Maybe there is an easier way to word it we'll see. Derek has not built a heli before so it will be interesting to see if he has a problem.
Gary
Gary, I thought it better to respond in a PM.
Piton
12-17-2006, 04:24 PM
Derek has not built a heli before so it will be interesting to see if he has a problem.
Gary
We are building the Bergen EB today at Gary's house. Gary has had me going by the instructions to see if I ran into any difficulties with the gear mesh. The gear mesh set up sequence was accomplished without difficulties or modifications to the frame. The present gear mesh is smooth and without binding or slop.
This is my first helicopter build, and the written instructions have been integral to my building experience. I mentioned to Gary today that a build video specific to the Bergen's would be a very useful tool for other people who will be building their Bergen's in the future. As Gary's experience and skill building these helicopters and setting them up properly to shoot video is not something that is covered in depth with the current instructions.
My background is in documentary video production, Gary and I discussed filming a build video in the near future. And perhaps a video for specifically setting up the Bergen's for aerial videography.
So, Gary, not only does this guy live in the same town as you but he's actually building it at your house? Not exactly a fair comparison. From what I've read on the forums, ALL Bergen owners need extensive help in building and getting a Bergen gasser to fly properly. There are numerous posts relating to how much time Bergen reps and Chris himself have to spend with clients in order to get their helicopters to fly. I was going to write more about my personal build experience but have chosen not to. Don't bother answering back, we're obviously not operating on the same page.
Gary Travis
12-19-2006, 09:14 AM
I will answer anyway, Yes he lives in the same town and yes he is building it at my home. He is a riend of mine and I have plenty of room to do the build. I have been letting him do the build and will be taking note if and when he has a problem. As far as Chris and Bergen reps spending alot of time helping customers, that is what we do and have done for several years. And yes some have needed help, but being fair I know of many who have not needed help. It has been my experience that most that needed help have come from the glow helicopter world and moved to gassers.
In the past and now in the present I have helped many people with Bergens as well as other brands of helicopters. I have seen people have problems with all types and brands.
Gary
Gary, if you want specifics as to the inaccuracies in my instruction manual I'll gladly post them here, but I guarantee you you won't be pleased. From the Pm I sent you I think you know perfectly well what I'm talking about: my manual has numerous discrepancies in both instructions and incorrect/outdated photos that required many, many phone calls to Chris. Yes, the customer service was excellent. However, the majority of these phone calls could have been avoided and a lot of my time and frustration spared had there simply been an addendum sheet included with the kit informing the builder of the changes made to certain parts, explaining the outdated photos and stating the corrections that needed to be made to include and exclude certain parts. Now, my most recent disappointment pertains to a painted canopy, or rather the lack of one. A painted canopy was ordered at the same time as the kit, September 6. All that was required was to return e-mail correspondence as to when a finished product could be expected. Courtesy, customer service, whatever you want to all it, e-mails were ignored, so an unpainted canopy was requested on Thursday, December 7. As of today, Tuesday, December 19, still no word on when a canopy will be forthcoming, and once again e-mail correspondence from Saturday, December 16th has been ignored. As for my particular build, Bergen has dropped the ball. Period.
cbergen
12-19-2006, 12:31 PM
Without any excuses being made as you have waited more than paitiently for your Canopy, your e-mail has not been ignored, there was not a lot I can do on a Saturday to find out where it is, so on Monday Morning the process started, and just as soon as I find out where it is, I will let you know as well.
In the meantime, another canopy was sent via UPS to you, and can only hope in this Christmas rush, it doesn't get lost as well....
Neither of these are your problem, just the way things happened.
As far as the manual is concerned, we do our best to keep the manual updated, but as we continually improve the kit and make slight changes, there may be delays in getting it into print.
There are also instances where we do things differently than other manufacturers, so experience with other kits do not necessarily translate to the Intrepids, which is why I feel it is very important to be available to answer these types of questions.
Thanks for the info, Chris. And all sarcasm aside, I do appreciate the update. Merry Christmas.
Bob
lperagallo
12-19-2006, 09:37 PM
Bob. I think some of your comments are off base. I started in the helicopter hobby about 25 years ago. At that time there was little to no information available. I was unsuccessful and gave it up. This year I decided to get back into the hobby and was surprised how things have changed. I built a Raptor. There was no way I could do it with the included instructions, that's why the raptortechnique site exists. I also had help from a fellow hobbyist after I did the build. There is no contacting the manufacturer of Raptor to get help :arggg:
Once I decided to build a gasser I researched the options and found the Bergen the best choice from a quality and customer service standpoint. I built an Intrepid EB in about two weeks, working a couple of nights and a day or two. I was able to do it without calling Chris. Once it was ready for its' maiden voyage Chris suggested that I come to a funfly and he would help me set it up. Since there are no Gasser flyers in the area I took him up. He carefully inspected my work and worked with me to get it flying smooth. He took the time to make sure I felt comfortable with it and he helps anytime I have a question. If you search here and the other forums, you will see the frustration of owners of other craft.
You know this is a hobby and as a hobby we spend time learning everything there is to know about our helicopters so we can be safe and successful in flying. There will always be something that will need tweaking so get used to learning evrytime you play with it. I wouldn't own another machine based on my experiences with building, rebuilding (yes, if you fly you will put in down) and working with everyone associated with Bergen. :lol: I sincerely hope you get your machine completed and have someone work with you to set it up correctly. This machine is not a Nitro bird that you can throw in the air and have the power make up for poor design or craftsmanship.
I'm not sure where you live, but I would be glad to help anytime you are in the Indianapolis area.
Lou
cbergen
12-20-2006, 08:04 AM
Just so the air is clear, there has been a very terrible snafu with his canopy, and it is in no way Bobs fault.
If I had known it would take this long, I would have suggested another route.
And the fact is, when you get frustrated with one thing, you end up with little patience for other, smaller things. I have been there myself.
All I can ask is a little more patience, it will get taken care of.
Stott1
12-20-2006, 09:28 PM
I will take the full brunt of the responsibility with the canopy. I will post no excuses, (if you need to know, PM) but to my personal defense, the emails to me were responded to. I in no way ever intended to cause a discredit to Bergen. Unfortunately Bobs was caught in the middle of my personal problems, and my ignorance. If there is a way that I can help make things right, I will.
lcyrace
12-20-2006, 10:18 PM
Now that we have all kissed and made up I will reply to the original topic. :lol:
After reading this thread I decided to check my mesh. I got my Bergen EB in a trade a week ago and have yet to fly it. It was built a few years ago and the owner was scared to fly it. Anyway, I thought the mesh seemed a bit loose since only about 1/2 of the teeth were touching. I discovered that once you set the correct height in the frame you actually pivot the motor on the 3mm bolts that go into the side of the engine case. After I tilted it back a little and slid the clutch bearing block back I have next to 0 backlash. Everything all lines up perfect. Just my $.02.