Tail belt/pulley issue ?

[Ticidytoc]

I was out flying the 600 the other day and found this:

http://www.helifreak.com/attachment.php?attachmentid=34843&d=1199662977

It appears the belt had gotten loose and the belt was trying to jump the pulley. This caused the tail to act strangely, it lost that locked in feeling. I landed and found the boom had slipped. I thought this may be problem during the build but decided not to address it and see if it would develop into an actual issue. It did.

I removed the boom, replaced the pulled and added a single wrap of clear packing tape to the section that inserts into the frame. Same thing I did for the T600. This seems to help keep the boom from slipping.

If any issues arise after this mod. I will post my findings here.

Keep an eye on belt tension folks.

[BobbySmith]

Man i have seen this a few times i use 3mm set screws in the frames on the right side i drill the holes out were the boom go's and screw them in jsut so they touch the boom and i adjust belt tension from the tail box
I also took the rear 5mm pulley off and added 3 3x8 mm bearings so it is 9mm wide so the belt cannot ride over that side any more if you want some pics i can take some

Bobby

[OICU812]

Yea I did same as Bobby for holding in the boom, it is almost like those little holes are made for it....


I had not thought of this issue with the tail pulley and using bearings, good idea, only I remember on my 14s the bearings would chew the belt apart abit from the slit between them. These three bearings do not have any negative effect on the belt at all thus far? Also are you just using a dremel to shorten the plastic stubs on both sides of bearings??

[LITHIUMSTATIC]

I also took the rear 5mm pulley off and added 3 3x8 mm bearings so it is 9mm wide so the belt cannot ride over that side any more if you want some pics i can take some

Bobby
Yes please show me some pictures.

Thanks

[Taipan]

It was too much hassle for me to wrap tape around the boom & inserting it into the frames w/o effing up the tape. So I removed the boom clamping bolts plus the 2 in front & prised the frame halves apart a bit. With some fiddiling was able to remove the 2 spacers for the 25mm boom. They're too thick & prevent a good grip even with the bolts tightened hard. Without the spacers there is a nice 3mm gap for the frames to clamp on the boom very tight.

As for the pulley, I replaced it with 2x 3x8x4mm bearings, 8mm wide total. I didn't want to shave down the plastic stubs so used some 3x5mm antenna tubing of the same dimensions & cut two 7.5mm pieces to fit. Used a sharp knife & rotated the tubing when cutting for a square cut. Don't tighten the pulley bolt too much or the plastic stubs will compress & disort the tail box CF frames. I did this primarily to get rid of static.

[BobbySmith]

I will post some pics
Shawn i used 2 smaller spacers on the (out put side) and the regular one on the other side ( fin side) they come wiht the kit or if you get a spasre canopy it comes wiht that as well i well post some pics and detail

I have seen the belt jump both sides if it comes off on the fin side you still, have alittle tail controll but when it comes off the output side you totally loose the tail

Two be honest i think it is from lubricating the belt it lets it slide around the stock 5mm pulley
Bobby

[Mercuriell]

RU guys sure the tail pulley is the primary problem ? If the belt comes off the front frame idler wheels it will likely track off the tail idler pulley and I remember some advice from DJ about making sure the belt tracks square in the front idlers.

[BobbySmith]

RU guys sure the tail pulley is the primary problem ? If the belt comes off the front frame idler wheels it will likely track off the tail idler pulley and I remember some advice from DJ about making sure the belt tracks square in the front idlers.

Yes i know about this as well using shims on the front pulley you can make it run reall true on the idler pulleys

[rscamp]

What do you guys think of using flanged bearings for the outer two M3X8 bearings when replacing the stock idler?

Rob

[OICU812]

What do you guys think of using flanged bearings for the outer two M3X8 bearings when replacing the stock idler?

Rob


Hmm I can see those gears turning! Nice idea, that might be an "extra" edge sort O' speak for sure. :wink:

[OICU812]

Yes i know about this as well using shims on the front pulley you can make it run reall true on the idler pulleys


On both my machines my belt runs on the bottom of those front pulleys. I used the stock spacing, you guys have done differently or what are we saying in regards to front ones...? On my 500 I tried adding different amount between the main gear and bottom bearing but the belt still rode in same path so when doing the 600s I just did as per manual.

[bladebraker]

It seems like adding 2 M3X8 bearings would afect CG. Does it?

[Flybar-less]

I have three bearings on both mine. If you are worried about CG throw a couple Ti bolts on the tail.

The flanged bearing, especially on the blade side, is a great idea.

[MrRoth]

Had a minor crash when the belt was slipping on the pulley..

Here's my mod on the 600...
http://modellflyg.habo.net/albums/album56/Logo_tail.jpg

[OICU812]

Had a minor crash when the belt was slipping on the pulley..

Here's my mod on the 600...
http://bp0.blogger.com/_x7rgxr2W2KU/R5CxjkzkwxI/AAAAAAAAAAk/wXRkSAOYwdg/s1600/image-upload-19-773542.jpe


Picture does not show....

[MrRoth]

Now?

[bladebraker]

MrRoth what size bearings is that? Thats looks great!