Look what I found on my 7Hv

[weaselbean]

Took it out for a test flight yesterday. It still has a slow tail wag now at high speed flight after rebuilding the tail thrust bearings and washers. So any way's I'm looking at my tail section when? I see the pin that holds the plastic tail hub drive gear has slid almost all the way out all on it's own. O so close to disaster for the second time! The first time I noticed the tail hub that holds the tail blade grips was loose. I could move it ever so slightly on the shaft. The only thing holding it on was the little set screw indention any looser on the set screw and the whole tail blade grips,with the tail blades would had went flying off crashing my 7Hv. I would also like to ad I take good care of my stuff maintenance wise (this is why I checked this) So when I got this helicopter! I went through and lock tighted everything.

So look at the picture below about 1/4 of the way from left to right notice? The tail gear pin has slid out all by it's self I shoved it back in then put some CA on each end to try to hold it in place. I will be keeping an eye on it from now on. I wish Compass would do away with the pins every where on this heli and do some kinda set screws or bolts? I love this heli and design don't get me wrong but it seems to be an accident waiting to happen to mine god I hope not! Then I will probally sell it and go back to nitro.

[whittb]

Darn, that would have been a nasty crash man. God thing you caught it before you spooled up. I will be checking mine tonight when I get home.

A set screw with a small hole in the tail shaft would be a nice fix.

[mtymyk]

I don't care for the pins either, however that's one thing I check every single flight is the pins on the whole tail assembly... Haven't had any come loose though, still holding in perfectly.


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[snipealot]

Those roll pins are usually very hard to come out, if you were able to simply push it back in I would not trust it to stay in. I have some spares, PM me your address and I will send you a couple.

[heathy]

Originally Posted by snipealot

Those roll pins are usually very hard to come out, if you were able to simply push it back in I would not trust it to stay in. I have some spares, PM me your address and I will send you a couple.

Agreed, normally a right PITA to get out! Do not fly that way and replace asap.

[jonny1]

Perhaps you could put a bit of shrink tube over the hole for the pin to secure it from moving.

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[weaselbean]

Great idea jonny1 if all else fails I will like I said I put some CA on each end and test flew it once today it held so far but now I'm Leary I will probably do jonny1's idea till I can get another one I forgot to mention that it seems like my plastic tail gear is out of round bad maybe that's why the pin worked it's way out? From the vibration. Grrr! Why is it so hard to get a nice smooth quiet helicopter? It seems everyone else's 7Hv is perfect... J/K I know I'm not afraid to chase it down it part of the fun.... right? haha lol

[Airworks]

in the manual , in the tips section , it says to put a drop of CA in there. Ive had CA'ed one for a longtime , so long ive worn a tail pulley completely smooth. never had an issue.

also.,,,you can expand it a little with the right sized "long" hex wrench.lol, they also make rollpin tools.

[kenny.c]

Ive also had the pin start to come out.....I glued it in place now....

Ken

[dunkonu23]

As a possible mod, is there any chance getting a metal output shaft pulley with two dog nose setscrews to hold the pulley with the dog nose setscrews going into recesses in the tail output shaft?

Scott

[weaselbean]

Be very care-full guy's!!! Here is the link to my RR thread this pin ended up shearing it's self off inside the tail shaft.... Witch then resulted in a crash for my nice brand new Compass 7Hv This is so dumb they also IMO need some kinda retainer for the tail hinge pins to. I was having trouble with one of mine trying to slide out on me. I'm not happy with that design either...BOO!!!!

http://rc.runryder.com/helicopter/t695099p1/

[Ah Clem]

weaselbean,

I know you are very upset, but please don't give up on it. As you know, there are a great many of us flying the 7HV without experiencing the tail issues that you had.

The thing to do is to find out what was different on yours (something out of tolerance?) and correct it. Nothing else flies like a 7HV.

I am very sorry you had the problem, sir.

[mtymyk]

+1, never heard of this type of failure, sounds isolated. Nonetheless, very sorry that it happened causing the crash.


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[dunkonu23]

On another brand of helicopter with a third party tail (CNC Heli V2/Sonix), the pin coming out of the output pulley was pretty common. Shearing the pin wasn't common at all. In my way of thinking, to shear the pin would require enough slop in the pulley to have the pulley repeatedly slap against the pin. After a while, something would have to give. Again, in another brand of helicopter, the tail output pulley, the one that doesn't fail (unless incorrectly installed) uses a metal pulley and dog nosed set screws.

Don't get me wrong, I'm not complaining about the design. I did ask Dave about this very thing last year at the Mid America Funfly when I was considering a 7hv, though. This seems to be isolated, but to me, it's cause to check this part frequently. I mean, it takes just a second to be certain it's okay.

Scott

[Lighty]

Pre-flight checks....

[weaselbean]

I do many pre flight checks befor I fly after I fly while i'm cleaning I check it all hell when I started noticing a pin slidding out problem I was even doing mid flight checks what more can I do leave a pair of vice grips on the damm thing while it's flying or maybe I should just mount a camera on it to watch the part while I'm flying 3-D Yea no problem there! (sorry but that kinda pissed me off ) I have been building and flying helis for 6 going on 7yrs I'm no noob by any means and safty is always on my mind

[360Wings]

On my 6hv I have wrapped a small slip of insulation tape around the circumference and applied some CA to the tape to make sure the tape doesnt come loose.. Prior to applying the tape I put some shoe goo over the ends of the pin. I cant see my pin going anywhere unless i push it out..

[weaselbean]

Before this happened I CA both ends of where the pin came out of the gear then I took and shrink wrapped over the pin to hold it in place then the dang pin just sheered it self off in side the tail shaft I find it odd that no Commpass field rep has made any comments on either one of my forums about either of these problem's.

[Ah Clem]

"I find it odd that no Commpass field rep has made any comments on either one of my forums about either of these problem's."

Post #12 above, sir, if a Team Pilot is an acceptable substitute for a Field Rep (which I was, at one time, too).

[GimpyGolden]

Maybe some Reps didn't want too pipe in seeing your still pretty angry. Not a lot of post's by reps in the last few days here in 7Hv though either.
(I'd know,I read them all)

This is the first I've seen this issue with the pulley pin, think I have read about the slider pin but cant recall an exact instance and don't recall it leading to a crash.

I now have 2 7Hv's one very recent kit which has Flat Clips to secure the slider pins and one kit from October last year which does not.

The older kit has 40-50 flights on it without either issue and the newer kit has only 10 but do not expect to see the issue since the pins are now secured.

The tail pulley one is just weird.
Were your tail bearings maybe having a side load on them due to overtightening the idler/roller on the tail case? Would cause extra torque applied to the pin.
Not questioning your build skills but easy to set the tail case sides of square if you go much past finger tight with that through bolt.

I think since the newer kits are including the clips they should at least be made available as a PN to those with "older" kits.
Or even supplied for free on request.

I know myself if I had the previous issues you did with pins coming loose I would ground my machine until said parts were fixed and issue resolved. Might be a twist of the knife but though the parts came unusable you still chose to use them(Sorry)

Read about this in a few threads with members holding SAB accountable for crashes resulting from the faulty pulleys.
SAB had issued a statement that if you use the faulty part you do so at your own risk and advise not flying until replacements arrive.

Some pilots took there chances and checked between flights but things happen in a split second in service. The pulleys split and down she comes.
Now they are angry(probably at themselves) and expect SAB to pay the fixin' fee.

I know in your case there was no notice from Compass about bad parts but seeing you've been flying as long as you have and the fact you did checks before, during and after flights you must have had a sense it wasn't a good idea to fly as is.
Had you contacted your dealer on the issue you likely would have received replacements pretty quick.

Sorry for the tough love and good luck getting this resolved or with your next machine.