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JR-Spektrum . Gyro Hobbies . E-flite

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Thunder Tiger Raptors 30-90 - Imperio > Exploding tail on your raptors.
 
 
Yug
rrProfessor
Location: UK. Herts

Holy cow. How many flights since new bearings/hub ?
06-07-2006 Over year old.
 
 
Barney
Key Veteran
Location: Inverness Scotland

Guy... Re-used the bearings when I changed the hub as they felt pretty good...what a numpty!!!LOL..

See blown brgs below

Thought I was on a winner when I got home.

I dismantled a spare Robbe Millie tail grip as I noticed the hub used the same shaft dia. There are two brgs as per Raptor + a spacer and a thrust brg. The thrust brg drops right in to the Raptor grip same external sizes..bu%$er me the internal dia is smaller..2mm bolt

06-08-2006 Over year old.
 
 
Yug
rrProfessor
Location: UK. Herts

2mm, that's small.

That looks like the QuickUK hub not the TT SUS hub.
I bought a round of QuickUK grips and hubs lastweek. After chatting with them on the phone, it seems they've gone to quite a lot of trouble to source decent quality bearings. I'd still like to find some contact angle bearings - they seem just the ticket.
My faith in TT bearings is diminishing somewhat, particularly after checking over my R50 on sunday to discover the upper mainshaft bearing was feeling really rough, and it's only had 70 flights since they were replaced.
06-08-2006 Over year old.
 
 
Barney
Key Veteran
Location: Inverness Scotland

Yes Guy, it's the new quick UK hub

BTW did you check out the RC-052 mainshaft collar I talked about a couple days back that you install above the lower mainshaft brg allowing Max travel of the swash..
06-08-2006 Over year old.
 
 
Yug
rrProfessor
Location: UK. Herts

That collar looks like the one I already use. However, it's mounted in the conventional position, but to allow more swash travel, I've thinned the top of it a little. I don't know weather I'm comfortable using a collar above the lower bearing because it means this bearing is doing all the work all the time as well as it loading the thin bit of plastic around the bearing reatainer - the bit some remove to make bearing swapout easy. All said and done, If the amount of work a bearing does were to be measured by how rough a bearing gets, then I have always found the lower bearings to remain pretty smooth, unlike the upper bearings which go bad much more quickly.

06-08-2006 Over year old.
 
 
averen
Veteran
Location: Austin, TX

Not to get off topic

I have a friend who had his jesus bolt let go and he had installed one of those thin QuickUK shaft collars. After the jesus bolt went and we were picking up the pieces we discussed putting another one of those against the upper bearing, but on the bottom rather than the top. That way if the lower jesus bolt let go at least the shaft collar would stop the shaft from pulling off of the heli.

Has anyone ever tried this?

Jared

Knowledge is Power, Power Corrupts, Study Hard...Be EVIL!
06-08-2006 Over year old.
HOMEPAGE  
 
 
Barney
Key Veteran
Location: Inverness Scotland

Guy..on the Quick UK tailrotor..the complete assy inc grips etc

Is there a thrust bearing fitted in them? or is it just the stock 3x8x4 as per TT?

cheers Brian
06-08-2006 Over year old.
 
 
Yug
rrProfessor
Location: UK. Herts

They haven't used a thrust bearing. They've used 2 high quality radial bearings. The screw holding them in is a cap screw and washer.
The blade grip bolt has an unthreaded portion of shank so there are no threads to cut into the blade root sleeve. The only thing which was a bit annoying was I had to make up some washers the correct thickness for a snug fit of the blade in the grip.
The width in the blade grip holder is 7.95mm, the blade root width is 5.05mm, so the washers should be 1.45mm. However they are 0.07mm too thin which means that when you tighten up the blade grip bolt so that the blades are snug, the holder will be brought out of square. As nice as the supplied washers look - black anodised, I opted for whittling down my own.

you mean 5 x 10 x 4 ?

Edit: the QuickUK tail hub & grips is 1g lighter than the TT parts.
06-08-2006 Over year old.
 
 
arceye
Veteran
Location: UK

Barney:
It looks from the dimensions you are giving like you are describing the V1 tail bearings, as I am sure the V2 bearings are 5x10x4 , in which case it may be possible to replace one of the bearing races from the V2 tail with the thrust bearing and a 1mm wide thrust washer from the V1 feathering spindle.
I have no idea if a single race and a thrust bearing as I described would work but I would be very surprised if nobody has already tried it.



Andy


Kasama Head :(
The Blingiest DOWNGRADE a Raptor can have
06-08-2006 Over year old.
 
 
Yug
rrProfessor
Location: UK. Herts

If you're gonna use a thrust bearing, then make sure you use a grooved washer as this will be able to take some axial load.
06-08-2006 Over year old.
 
 
Barney
Key Veteran
Location: Inverness Scotland

Ok I have a problem... I've just ordered 4 of d3xD8xW4 from Revolution Models...untill I can come up with a better idea..

The above is the size listed in My Raptor 50 Manual ..page 12 bottom illustration..item (8) HMV1050...part no being(PVO200)

I just downloaded a Titan Manual and they list them as HMV1050ZZ d5xD10xW4 part no PVO526!!!

Both use the same tail hub PVO151 & grips PVO148..tail rotor shaftPVO030

the only difference seems to be the tail pitch slider fork which now uses pins & circlips PVO017 against the Titans PVO504
06-08-2006 Over year old.
 
 
3dbasher
Heliman
Location: lincolnshire uk

touch wood never!

had that problem with the old v1's never seen it with v2's myself, anything to do with the gyro stopping too hard on piro's?

Was it supposed to do that!
06-08-2006 Over year old.
HOMEPAGE  
 
 
Barney
Key Veteran
Location: Inverness Scotland

3dbasher..the problem is there is no thrust race so the bearings are being pulled apart. On this model I'm running a 401/90mm combo at around 1900

I would consider the stops quite soft compared to my Dyna with it's CSM720..

The tail blade holder on the Dyna/Millie/Futura uses two ball races , a spacer and a thrust bearing and the internal/hub dia is smaller than the Raptor. Robbe's use a 2mm bolt to retain it all against the Rap's 3mm bolt.

Another thing about the Raptor brgs compared is they have a larger internal hole but the same outside dia meaning the 'ballbearings & the track they run in' is shallower which requires smaller balls which certainly won't be helping.

I was planning on making a hybrid tail but can't quite figure it out yet, as I can't machine anything

Because TT use the larger bolt size (which is not actually necessary) you can't get a suitable thrust brg that I am aware of.

What would work would be a hub like the Quick UK one except machined down to accept the smaller inside dia brgs that Robbe use as they are a drop in fit to the blade grip.

The problem with this is the bolt is 3mm against the 2mm Robbe item and the internal thread stops level with the shoulder on the hub so it would be weakened to much.
BUT if the hub used a 2mm bolt it would most likely be OK the machine it down to accept the Robbe items

When you look closely at the Robbe Item it becomes obvious they have put a lot of thought into it as it has a longer shank for the brgs/spacer etc..because of this the retaing bolt and hole does not reach so far down stopping well short of the shoulder so not weakning it as TT have done

So if your listning Quick UK you saw it here on RR..and I'm going to patent it..LOL...

Later on I will post a few piccy's as it's much easier to understand
06-08-2006 Over year old.
 
 
rob10000
Key Veteran
Location: Western Massachusettes

The easiest solution is to swap the entire tail rotor, from the hub out from another model with thrust bearings.
I use a JR Vigor tail on my 90SE, and I've upgraded my 50's to the SUS tail hub.See my earlier post in this thread, or go here for more info.

http://www.runryder.com/helicopter/t205120p1/?p=1559819
06-08-2006 Over year old.
HOMEPAGE  
 
 
Barney
Key Veteran
Location: Inverness Scotland

OK Here we are

Top left is the Raptor grip with the Quick UK SUS hub. Top right is the remains of the standard brg..(inner race only) so you can see the internal dia.

The bearing below that is the robbe ballrace which has the same external dia as TT but internal dia is smaller

Below the grip is a Robbe tail rotor hub from a Millie/Se etc as you can see the shank is longer to accomadate the two brgs, spacer,and thrust brg. The securing bolt is 2mm and hole depth is about 3/4's of the shank so strength is not compromised, but the threaded/drilled portion is a little shallow for our use.

It might be feasable to trim the robbe hub as the hole depth is about the depth of one brg providing it's threaded all the way down? The only drawback is you will have to fit a spacer so you can leave plenty of thread for the securing bolt..see piccy

The grip below left has the robbe thrust brg & ballbearing and is a perfect drop in fit..the one on the right has the TT brgs (remains of any way.)

06-08-2006 Over year old.
 
 
Barney
Key Veteran
Location: Inverness Scotland

OK next question..If I fit the thrust bearing do I fit it to the outside or inside..Also the brg is directionial..same as a main blade thrust setup with one hole larger than the other???
06-08-2006 Over year old.
 
 
turboomni
Elite Veteran
Location: 63 Rambler Down By The Dumpster

Been reading this horror story with great intrest. I have not had this happen but would like to know , does this happen withheavier than stock tail blades mostly?
Also is there a common headspeed that this happens? For example guys with their 50 pushing 2000 rpms with carbon tail blades on a regular basis and then it may throw a blade at high or low speed [like running it up on the ground}?
Do guys with stock tailblades running 1800 to 1900 max headspeed suffer from this? Does this only happen when pushing the performance envelope?
Thanks

Setup is everything, All my heli's can fly better than I can pilot them
06-08-2006 Over year old.
 
 
Jason Bell
Elite Veteran
Location: San Diego, Ca

will this happen to a 50 and if so what are the pre signs of it happening before flying it and making it go boom!!!

Team Avant
Team ElyQ
Flight Power USA
Aerospire
Vblades
06-08-2006 Over year old.
HOMEPAGE  
 
 
averen
Veteran
Location: Austin, TX

I would think 90s would be more prone to this. Larger tailblades and just more stress overall in the tail area, not to mention that the 30-90 all use the same tail parts.

However I'm sure this can happen with anything 30 and above. Although I have not had this problem and don't personally know anyone who has. Having said that I'm going to find my thrust bearings and put them back in the tail...can never be too safe

Jared

Knowledge is Power, Power Corrupts, Study Hard...Be EVIL!
06-08-2006 Over year old.
HOMEPAGE  
 
 
Flying Tivo
Veteran
Location: Monterrey,NL,Mexico

No need to beat around the bush

The answeres have been given on prior post.
Use stock raptor parts and just change one bearing for a thrust bearing, or change to the new CNC QUK tail hub and replace one of the bearings with thrust bearing. This are the easiest solutions to the problem. If you want to take chances go ahead, if you want to sleep at night then make the changes.

Felipe

If life throws at you lemons......Squirt some lemon juice in the eye of your enemy!!!!
06-08-2006 Over year old.
HOMEPAGE  
 
 
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Thunder Tiger Raptors 30-90 - Imperio > Exploding tail on your raptors.
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