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HelicopterMain Discussion › DYI (do it yourself) Third bearind support for Raptor 50....revisited.....
01-26-2007 12:27 AM  10 years agoPost 1
JuanRodriguez

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The Villages, Florida

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Hi all,

There's been a couple (or three) posts recently describing the "upgrade" third bearing support to aid in reducing or eliminating the bearing/pinion failures many have had (or possibly will have ) with the Raptor line of helis....

You can do one of two things..... you can purchase the "upgrade" as has been suggested OR (IF) you have a lathe and some basic skills, you can make one for yourself. If you're cheap, like me, the latter choice will prevail....

Firstly, to begin my "thread" I have to make a confession......

I do not believe this is ROCKET SCIENCE, BRAIN SURGERY or anything so complicated the average bloke should not be able to accomplish....

What I do know is that since the top portion of the pinion that sticks above the "failing" bearing is a "press fit" or "glued" into the "upgrade" via loctite, JBWeld or whatever, it stands to reason that the entire "upgrade" spins (thanx, ulfinator).... So, right of the bat, the OUTER DIAMETER of the upgrade piece where the bearing seats AND the lower portion of the upgrade that butts up against the pinion bearing has to be SMALLER than the internal measurements of the frames where this part is spinning......

That being said, what I hope to accomplish is to make a couple of the "upgrades" to install on my machines AND to provide you with the dimensions and any other "tip" I may run across as I proceed with this project so that you don't have to RE-INVENT THE WHEEL !!!......

If anyone has any thoughts or ideas that have not already been posted elsewhere, please feel free to chime in.....

Here is a quick and dirty explanation of how and why it works from none other than 2L Time....
I would use green loctite on the pinion bearing. It's made for this purpose. The upgrade does spin with the pinion. It fits tight on the end of the pinion, and the bearing on the end rides on the start shaft. It basically makes the pinion longer and supported at the top by a bearing riding on the start shaft.
Sharing information is the biggest strenght of RunRyder ....that's what it's all about....

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01-26-2007 01:19 AM  10 years agoPost 2
playfair

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Rochester, NY

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Never a dull moment, eh, Juan? LOL
Actually, this "upgrade" is a little more precision oriented then you're making it sound...
I tried to knock one off today, but it had a slite wobble to it (cheap lathe). Made me realize that ANY un-trueness will cause more issues than it solves by beating the crap out of an already marginal design.

As for tips, here's what I have so far:
The second bearing can be the same one used for the tr grips. The larger OD should still fit inside the frames given reasonable wall thickness to the part. I was thinking of set-screwing to the pinion, but this really needs to be a press after realizing how important trueness is.
I'm going to try using delrin, as we're not cutting stones here and it's more forgiving in the press-fit tolerance department.

Another thing I noticed is the tolerance on the start shaft is tighter where it fits into the one way clutch bearing, and falls shy of 6mm around the center of the shaft causing a pretty loose sliding fit to the additional bearing.

Keep us posted of your progress!


The sky is our canvas

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01-26-2007 01:45 AM  10 years agoPost 3
JuanRodriguez

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The Villages, Florida

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Never a dull moment, eh, Juan? LOL
Never... otherwise, it's not worth going on....
Actually, this "upgrade" is a little more precision oriented then you're making it sound...
I tried to knock one off today, but it had a slite wobble to it (cheap lathe). Made me realize that ANY un-trueness will cause more issues than it solves by beating the crap out of an already marginal design.
Agreed.... and for that reason, me and Ulf are thinking that it is better NOT to have things as a "press fit"..... perhaps it might be better to leave things a slip fit and assemble the entire shabang with green locktite and let it set off.... that way, it might have a tendency to "self align".....
As for tips, here's what I have so far:
The second bearing can be the same one used for the tr grips
I haven't taken any measurements yet but did you mean to say Main Blade Grip bearings ??
Keep us posted of your progress!
Will do....

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01-26-2007 02:21 AM  10 years agoPost 4
ulfenator

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Rochester, N.Y. USA

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I tried to knock one off today, but it had a slite wobble to it (cheap lathe). Made me realize that ANY un-trueness will cause more issues than it solves by beating the crap out of an already marginal design.
I think you would have to bore the bearing hole and the 8mm through hole in one operation without removing the piece from the lathe in order to keep it straight.

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01-26-2007 03:20 AM  10 years agoPost 5
playfair

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Rochester, NY

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Ulf- That would work! I see you're in cahoots with Juan... Put me down for one! I do think delrin will work fine, and I have raw material for several if it helps

Juan- Correct: MR grip bearings.


The sky is our canvas

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01-29-2007 04:25 PM  10 years agoPost 6
JuanRodriguez

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The Villages, Florida

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Hi all,

This past Sunday morning I had some time to spare so I decided to give making the upgrade a try...It took me LESS that one half hour to make. That does not count the little bit of time Ulf Andersson (ulfinator) and I spent talking about some “how to’s” and some other concerns over breakfast on Saturday.

There are basically two ways to go about installing the pinion end into the piece as well as the bearing into the piece.... We discussed the “press fit” vs the “slip fit” and concluded that the best approach (for me/us) was to machine the piece so that BOTH the bearing and pinion are a “slip fit”. That decision was made for a couple of different reasons.....The main and most important reason is that by keeping both fits as a “slip” rather than “press” fit, the entire assembly would in essence become “self aligning”. The “trick” will be in using a set (or one half) of a frame set as a “jig” to hold the pieces in alignment WHILE the loctite cures. Providing the little extra “wiggle room” for the bearing and the pinion to be able to “float” will assure everything is straight during the cure.

The second reason for going the slip fit route is that I like to subscribe to the KISS method (keep it simple, stupid).... Sorry for the old cliche but it really applies sometimes !! Please bear in mind that it doesn’t mean that you can get sloppy as heck and expect good results..... We’re still talking about machining the critical areas to a couple of thousands or so tolerances.

With all of the above in mind, a material list of sorts comes to mind...... Whenever I do these “home brewed” projects, I like to use the materials I have on hand whenever possible. If you have to go out to buy bearings and round stock to make this piece, you’re much better off buying the commercially available upgrade and be done with it. But if you’re like me (I think I already mentioned that I’m CHEAP) and you like to tinker, this project can be really fun and rewarding.

You’ll obviously need a piece of round aluminum stock to make your piece. The OD of that piece is not critical to a degree in that if just needs to be smaller than the space between the frames but large enough to support the bearing. The bottom part of the piece necks down because it needs to clear the “bosses” where the bottom pinion bearing is in place. Again, nothing real critical here. I put two frame halves together and took a quick measurement and then gave that bottom piece about 10 thousands clearance. The piece of round stock I used was left over from another project and measured .633 OD (16.09 mm). It seemed like the perfect overall OD to start with given my bearing choice. The dimensions of the finished piece turned out to be as follows:.633 OD (16.09 mm) (on the bearing end) x .571 L (14.52 mm). Having these overall dimensions places the bearing approximately half way point between the upper and lower main frame bearings. The part of the piece that “steps down” measures approximately .320 (8.14 mm) and is turned down to about ½ the overall length of the piece.

For the top bearing, I used a top start shaft bearing I had on hand which measures 6d x 15D x W5. Given that the bearing’s OD is .590 and the OD of the stock is .633 that means that the bearing is supported by approximately 21.5 thousands of material (.633-.590 /2). We felt that given the application that it was plenty. As an alternative, the Main Blade Grip bearings can also be used. They measure 6d x 13D x W5. Take a look at the photo below and you’ll see the bearing ready to be installed into the piece. You can push the bearing until it seats with slight finger pressure and pop it back out from behind using a pen or pencil.

The operation of making the piece is fairly basic...... First, face off the piece and use a center drill to “mark your spot” . I like to “step drill” my hole which means that you start out with a smaller drill than the size you’re intending to make and work your way up slowly. If I were to “press fit” the pinion the last pass would have been made with a reamer.... However, as already mentioned, I decided to make the pinion and bearing fits a “slip fit”. My pinion end measured out to .310 (7.88 mm) and so a 5/16 drill (.3125) seemed like the perfect choice. It is a little more on the “loose” side than I would have liked but in reality, the loctite will be perfect for this application.

After drilling the “through” hole, I turned about ½ of the piece down to .465 (11.83 mm). This is the end that the pinion end will fit into. Then I flipped the part around on the lathe and used a live center into the drilled hole to help keep the piece in alignment while snugging up the chuck. I then faced off the piece and bored the hole to accept the bearing. That dimension , of course , will depend on the bearing size you choose to use. I got it “close” initially to the point I knew would be a nice press fit and the continued to take some very small “skim” passes until I got the slip fit I was after..... It’s really easy to overdo it so you have to be very careful otherwise you’ll be making another !!

Take a look at the boring tool I used..... Nothing more than a small end mill (1/8 inch, I believe) which I ground the end to about a 45 degree angle. This “boring bar” allows me to get tight into corners and do a neat job. It’s the same tool I use whenever I replace the old liners in a clutch bell.

Well, there you have it. Here are some additional pictures of the finished product.

I apologize for the length of this post but I don’t see how I could have made it any shorter and still make sense....

Lastly, credit has to be given to the person that came up with this idea to begin with, John Vugts. I cannot personally vouch for the effectiveness of the "upgrade" but the idea is sound and has gotten favorable reports from those using it. Thanx, John......

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01-29-2007 07:25 PM  10 years agoPost 7
Peefor

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Norfolk UK

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Interesting post Juan

I'm in the process of doing the same thing myself, but concluded that both internal holes should be carried out at the same lathe setting.

By reversing the part in the chuck, there is a danger of losing concentricity.

The pinions are also not all the same size, but by coincidence the pinion I have is 7.88mm diameter. I have read reports of the QKUK one having a differing fit on the pinions.

Pete

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01-29-2007 09:25 PM  10 years agoPost 8
JuanRodriguez

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The Villages, Florida

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Pete,

You're absolutely right.... I should have bored the through hole AND the bearing hole at the same time (without flipping)....

Perhaps I got "lucky" because my assembly seems to run true, at least to the naked eye..... Or..... I may have gotten away with it due to the self aligining "slip fit" method I chose to use over the "press fit" method which would be less forgiving.....

Good luck on your project.... let us know how it turns out !!

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01-30-2007 07:28 PM  10 years agoPost 9
jmkirsch

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Rochester, NY

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Nice job, Juan!

I can verify that the slip fit design was a good idea. Rick's used to sell an upgrade exactly like this for the V1 Raptor and it was a slip fit design secured with Loctite. I believe they also suggested crimping the unit on to the pinion; so much for precision alignment I bought one and have a few years of use on it with no issues. If I remember correctly, they decided not to make a V2 one because the problem was "fixed." Interesting that the idea was resurrected now that we know it wasn't really fixed.

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01-31-2007 02:06 PM  10 years agoPost 10
JuanRodriguez

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The Villages, Florida

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Thanx, Jake...

It was a fun and "quicky" project to do.....

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01-31-2007 05:50 PM  10 years agoPost 11
Peefor

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Norfolk UK

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The dimensions were changed from my original thoughts. Settled on overall length of 15.00mm. Top section 16.00, bottom is 11.00mm. The step is 7.00 from the top. Bearing 13 x 6 x 5 wide. The narrower bottom section clears the small step on the plastic frame a little better.

Currently working on a better clutch bell with the larger bearing, so any problems in this area should be a thing of the past..........if only

Pete

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01-31-2007 06:10 PM  10 years agoPost 12
JuanRodriguez

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Nice Job, Pete !!!

I take it that the reamers worked out fine ??

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01-31-2007 07:06 PM  10 years agoPost 13
Peefor

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Norfolk UK

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Juan

The reamers worked very well, thanks. The 7.85mm was a bit small, 7.88mm spot on, so have not had to use the 7.90mm.

Pete

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02-01-2007 11:05 PM  10 years agoPost 14
ulfenator

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Rochester, N.Y. USA

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I wish I had a 7.88mm reamer it would be a lot easier and faster, but I have made one that is press fit for both the bearing end and also for the pinion. I got it installed in Raptor last night, I won't be test flying it until spring.
I also made two that is slip fit I plan on using loctite to secure it to the pinion and bearing, they are going to be my backup parts.

Juan, thanks for the bearing.

The job was not very hard but all I had was 7/8" round stock to work with, so it took a while to make, and a lot of chips.

Ulf

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02-02-2007 02:27 PM  10 years agoPost 15
JuanRodriguez

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The Villages, Florida

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Juan, thanks for the bearing
No problem, Ulf. That's what I'm here for....
The job was not very hard but all I had was 7/8" round stock to work with, so it took a while to make, and a lot of chips.
In my case, I just "happened to have" a piece with an OD that was "adequate" for the job. So, no intitial turning was needed.

For the benefit of others that might want to try to make one, the dimensions are not all that critical. Again, you're not building a rocket ship......

For the overall diameter, anything that you might have on hand that fits between the frames (without rubbing) to start with is good enough. The other main consideration regarding the OD of the piece is that you have enough "meat" to support the top bearing adequately....

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02-02-2007 03:46 PM  10 years agoPost 16
Peefor

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Norfolk UK

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you're not building a rocket ship
You haven't got rappy 50 then?

The overall outside dimensions are not important, but the larger it is, the more weight. The narrow section at the bottom does not want to be any larger than 11.80 or else it will hit on the bottom bearing retaining lip of the frame. ( I settled on 11.00 mm)

Pete

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02-03-2007 01:17 PM  10 years agoPost 17
JuanRodriguez

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The Villages, Florida

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Pete,

I agree..... making the OD larger than necessary adds additional weight that is not needed..... Using a Main Blade bearing looks to be perfect and keeps the piece small.

I have to make a second piece for Raptor #2... I'll see what roundstock I have in the scrap bin....

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02-04-2007 02:20 PM  10 years agoPost 18
Al Magaloff

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12,199 Posts- Enough Time Wasted. See Ya!

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Nice job Juan. It's good to see we can all still fly Raptors, without TEAM Raptor telling us what to think.

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02-04-2007 04:19 PM  10 years agoPost 19
2LTime

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Walworth,NY

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Juan , real nice job. Looks perfect. I guess we'll see if this part actually helps the pinion.
For the top bearing, I used a top start shaft bearing I had on hand which measures 5d x 15D x W5.
Are you sure? I'm pretty sure the start shaft is 6mm.

Jeff

If you can't learn to do it well, learn to enjoy doing it badly.

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02-04-2007 10:05 PM  10 years agoPost 20
JuanRodriguez

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The Villages, Florida

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Thanx, Jeff. I appreciate your comments....

You're right about the bearing, it is 6mm ID. Thanx for catching the typo....Dimension has been edited....

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HelicopterMain Discussion › DYI (do it yourself) Third bearind support for Raptor 50....revisited.....
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