View Full Version : How to avoid throwing a tail rotor blade on a raptor
Magic Man
07-12-2006, 01:14 PM
First of all, if you have a stock setup GET RID OF IT!!!
The tail rotor hob is held in with a standard all thread, that also acts as a set screw to hold the tail rotor hub on the shaft. The all thread sticks out enough to put a nut on, to hold the tail blade grip.
This setup is weak, and will fail!
Instead, go out and get two 3 millimeter set screws, and screw them all the way down the hole and tighten them on the shaft.
This will keep the hub on the shaft. then get yourself two 3 millimeter STAINLESS screws, and screw them in (with loctite of course) to hold
the tail blade grips to the hub.
This setup will be bullet proof
Rafael23cc
07-12-2006, 01:20 PM
Or you can get the new Stainless Steel upgrade from TT and be done with it.
Even tho I agree that the pressure of the bolt acting as a set screw AND a grip holder is enough to cause a failure, the aluminum hub does not offer enough strutural integrity either.
I had one aluminum hub fail because of overtightening, and another one fail because of fatigue.
Now I have the SUS hub in both of my Raptors.
Rafael
BarracudaHockey
07-12-2006, 01:28 PM
PV0499 the once piece SUS tail hub and be done with it, 6 or 7 bucks.
Magic Man
07-12-2006, 01:32 PM
well I still stand by my first obversation
"if you have a stock setup GET RID OF IT!!!"
And my fix is the cheapest. and most hobby stores have the parts.
Rafael23cc
07-12-2006, 02:13 PM
"if you have a stock setup GET RID OF IT!!!"
I agree, but the real easiest and SAFEST solution IS the SUS hub.
Rafael
Janek
07-12-2006, 07:24 PM
The only bullet proof solution is PV0499, shame that TT still don't supply this as standard on their new kits.
mantistw
07-12-2006, 10:45 PM
does the tail hub in the titan 50 need to be replaced or is it the right one ?
Janek
07-13-2006, 03:14 AM
The new TT kits, including the Titan, do not contain PV0499
BarracudaHockey
07-13-2006, 09:53 AM
If there is two long set screws with locknuts holding the bearings in its the old hub and susceptable to failure if the screws are over tightened or if you bang it on something. The tail blade flying off, with a driven tail rotor is a BAD thing. Trust me on this.
Rafael23cc
07-13-2006, 10:15 AM
The tail blade flying off, with a driven tail rotor is a BAD thing. Trust me on this.
There is little the throttle hold can do for you. I learned the hard way too.
Rafael
BarracudaHockey
07-13-2006, 10:35 AM
It looks kinda cool spinning out of control while the tail bobs up and down. It probably would have looked even cooler if it wasnt my helicopter.
Rafael23cc
07-13-2006, 11:00 AM
I was doing some manuvers about 20ft off the deck in Idle up2 (close to 2000rpm) when I saw something fly off the heli. Almost by instinct, I flipped the throttle hold, but the rpms were so high, the heli was bobbling so bad and I was so close to the ground, that it was the worst auto I had made since my first attempt ever at an auto.
Rafael
JeepFan
07-16-2006, 01:25 AM
This has been a known problem for many years. Most places carry a one piece aftermarket hub. Many years ago when I bought my R30 V1 from GR8Lakes, he stocked a one piece hub, which I bought and installed before I flew.
Pokerstar
07-16-2006, 12:44 PM
I am building a Raptor 50 Titan, and based on everyones advice, I put in the SUS tail hub PV0499 during the build. Thanks!
:noteworthy
Deftone45075
07-27-2006, 04:08 PM
Gonna look for the SUS hub also for my titan, but Heliproz is out of stock on them.
Has anyone heard of problems using the regular bearings in the tail grips instead of thrust bearings? I heasrd of stress causing the outer races to seperate on the stock bearings.
BarracudaHockey
07-27-2006, 04:27 PM
http://www.ronlund.com
http://www.onlyraptors.com
one or the other should have it.
flybarless
08-04-2006, 01:43 PM
www.rchobbiesandmore.com also stocks the hub. Thats where I got mine.
bgjames111
08-07-2006, 12:29 AM
had the same problem today. I knew better too! :arggg: I really think Ace should be giving a crash kit and a pair of carbon blades to anyone who has had this fail!!! come on lets petition :glasses2:
Mike C
08-12-2006, 09:05 AM
had the same problem today. I knew better too! :arggg: I really think Ace should be giving a crash kit and a pair of carbon blades to anyone who has had this fail!!! come on lets petition :glasses2:
How about a new Kit :shock: only thing I saved was Metal head .
I didn't know about this till 2 weeks ago inverted 100' up (still learning inverted)
Spawndn72
08-13-2006, 04:51 PM
Happened this weekend at IRCHA to me. First flight on the raptor I bought from Will.
Oh, well at least the vendors were right there with all the parts I needed.
Did not see any of the SUS tailhubs though, guess I will have to order one.
Thanks for the info guys, this is exactly what I was looking for.
ferincr
09-21-2006, 10:17 PM
Well, this thread got me worried.
It seems like I'm ordering the PV0499 too.
One other question, Isaw that there is a thrust bearing for it, should I get it ???
Thanks,
MarkWebber
09-23-2006, 07:12 AM
Has anyone heard of problems using the regular bearings in the tail grips instead of thrust bearings? I heasrd of stress causing the outer races to seperate on the stock bearings.
Any answers to that question?
BarracudaHockey
09-23-2006, 08:07 AM
I've had about 200 flights on the upgraded hub and the radial bearings and haven't had a problem since I installed the SUS hub.
If your worried about thrust bearings the new Quick UK hub has them but you have to get the whole tail mechanisim I think.
Part number RT-11 cost 65 dollars http://www.quickuk.co.uk/acatalog/r_index.htm
flyinfool
09-23-2006, 10:26 AM
The thrust load that the tail rotor puts on the bearings is way over the max thrust rating of the radial bearings. Can you say time bomb.
You really need the thrust bearing in there. The 2 radials will work for a little while.
Don't take my word for it.
Take one complete blade grip and blade assembly including all hardware, with one bearing in place and weigh it.
Then check and mark the CG of that assembly.
Reassemble the tail.
Now measure the distance that that CG mark is from the center of the tail shaft.
Her comes the fun, Google for the formula (It's not a complicated one) for centripetal force and calculate how much thrust force is on that bearing.
Go to the websites of several bearing manufacturers and look up the max axial load for that bearing size.
Now you will know just how much thrust YOUR setup has.
ferincr
09-25-2006, 12:33 PM
Ok, let's beat that dead horse one more time :DH (I just wanted to use the emoticon, I think is cool)
Which seems to be the problem here? is it that the hub is made of aluminum? or the set screws? or both?
The reason I'm asking is because I'm at the UK for a couple of weeks and I'd like to order as many pieces as I can 'cause once back home (Costa Rica) I'll be stuck with what I got.
It seems like the options are either to order the PV0499 or the other one I saw is that Quick UK has one Tail hub made of SS but it looks exactly like the original aluminum one (with the set screws) the good news is you can get the thrust bearings for that one which I don't know if they'll fit on the PV0499.
Any suggestion is appreciated,