7HV VBar tail blow out

[alexmit]

Originally Posted by Rotoritis

I remember in the manual it talked about not setting the tail to its full throws, I think in an earlier post you said you had full, this may have help lock that tail up on your crash flight. Full throw can cause the tail blades to stall, anyone else running full L and R on the tail?
Sounds like the gov gain issue may be the problem, but head torque is overcoming the tail.
Hope you get it worked out, I know we would all like to get our eyes on it, to look it over.

Mine has nearly full throw (within 2mm) and I run KBDD 104s on the tail. You will see in this video that it works fine. This is my friend flying my heli... I wish I was this good. He was also taking it easy compared to when he flies his own helicopter.

[ame]http://www.youtube.com/watch?v=OSo4TBDaJ0I[/ame]

[dunkonu23]

That was nice, Alex. That tail looked way locked in. Great save, too!

Scott

[OverTemp]

We need a thread with a list of wives tails.

If you are stalling your tail blades they are too small or your tail rpm is too low.

[alexmit]

Originally Posted by OverTemp

We need a thread with a list of wives tails.

If you are stalling your tail blades they are too small or your tail rpm is too low.

Are you saying some 'wives tails' stall? Couldn't resist... :-)

[Rotoritis]

Well they called Titanic Unsinkable, I assure you, you can stall blades. Its in the manual, was just asking. Im not making stuff up

"

"It is important to limit the servo travel to the endpoints of the slider shown below. Too much
travel can cause a stall and lead to a loss of tail authority." Page 17 of 7HV manual

[dankcincy]

So Ive decided to wait till this weekend when Im well rested to do this. If something goes wrong again I would like to have all my wits about me.

[dunkonu23]

Sounds like a good idea, Dan. Even if there is problems, you will get it sorted.

Scott

[jt45255]

good idea i cant bear to see u crash it again.plus i wanna fly it !!!! he he he

Originally Posted by dankcincy

So Ive decided to wait till this weekend when Im well rested to do this. If something goes wrong again I would like to have all my wits about me.

[Rob43]

Whoa! Your buddy can fly! Looks to me like the 7HV suits him pretty good. I think he was having way too much fun flying your bird!!!

I actually interpreted the manual to mean not that the blades would stall, but that the slider could hesitate or resist coming back from extreme throws. I don't detect anything close to binding, but maybe it takes more effort for the servo to return to the desired position from an exteme throw. I've experienced this on a former model. The cause was the hub was positioned slightly too far from the case. The shaft was not flush with the hub bore, but just a bit recessed. This caused some excess throw away from the tail case. It resulted in a tail kick when aI pulled high pitch moves. Soon as I corrected it, the tail was perfect. Not sure...just sayin'.

[alexmit]

Originally Posted by Rob43

Whoa! Your buddy can fly! Looks to me like the 7HV suits him pretty good. I think he was having way too much fun flying your bird!!!

I actually interpreted the manual to mean not that the blades would stall, but that the slider could hesitate or resist coming back from extreme throws. I don't detect anything close to binding, but maybe it takes more effort for the servo to return to the desired position from an exteme throw. I've experienced this on a former model. The cause was the hub was positioned slightly too far from the case. The shaft was not flush with the hub bore, but just a bit recessed. This caused some excess throw away from the tail case. It resulted in a tail kick when aI pulled high pitch moves. Soon as I corrected it, the tail was perfect. Not sure...just sayin'.

Caleb is a wizard in my opinion. You saw what is basically a warm-up flight with somebody else's helicopter. He was being careful. You should see him fly his Logo.

I am running a MKS BLS 980HV on the tail. Maybe that is why it can handle the load. I'm at 6V currently, but intend to turn it all up to 8V on the WR Super BEC. I just put a 4530-500 Quantum motor in it for Huntsville this weekend, so I will test that before I up my servo voltage. I really wanted El Brute or the new Scorpion Ultimate, but have heard good things about the Quantum.

[OverTemp]

Originally Posted by Rotoritis

Well they called Titanic Unsinkable, I assure you, you can stall blades. Its in the manual, was just asking. Im not making stuff up

"

"It is important to limit the servo travel to the endpoints of the slider shown below. Too much
travel can cause a stall and lead to a loss of tail authority." Page 17 of 7HV manual

When I get time I'll find a previous write-up I did and post. Short cliffs notes...
Your gyro asks of the tail only what it needs. If you are relying on your endpoints to stop the blades from stalling, then when the slider reaches the endpoint, it means the gyro is asking for more throw, but can't give it due to a restriction you imposed... what's the result? Blow out. Tail needs more thrust, but it's not available.

How do you overcome? More RPM or more effective tail blades... More thrust for less angle to keep you off of stall.

It is impossible to tell at what angle the tail will stall in a dynamic situation because of changes in the relative wind at the tail. There are dynamic situations where it would be physically possible to stall the tail with very little angle at all. The only thing protecting you is the fact that the gyro wouldn't ask for those angles because, if the tail power is sufficient, they would never be required to produce a desired effect. More to follow on that discussion.

Cheers

[dankcincy]

Well, I got out of work early today so took the 7 out. Lets just say that the nylon screws did their job. I still have some bugs to work out in my setup it seems.

[buzzsaw 46]

Noooo, not again!

[dunkonu23]

I'm sorry to hear that, Dan. I'm glad the screws did their job, though. Just take your time getting out any broken screw pieces. That's the only downside to nylon screws. Damn, bro! You WILL get this. I'm certain of it!

Scott

[Rob43]

Have you checked with Mr Mel on this? Does he have some wisdom on the issue?

Aside from him, r1sportbike is about as expert on Vbar as anyone I know.

Of course, creds will always go to Belcom for resolving the worst piss-me-off problem I have ever had since going Compass.

[dankcincy]

Yup, No biggie though. This thing crashes great which is why I bought it. As close to an MCPx as you can get in a 700 class heli. Some nylon bolts, servo arm, Tail blade grip and hub. Thats about it. Blades went round 2 with terra firma and are no worse for wear. I almost saved it this time though. I had it 2ft off the ground, hit TH and then something goofy happened and it slammed into the ground. More of a hard landing then anything I would say.

[dankcincy]

Originally Posted by dunkonu23

I'm sorry to hear that, Dan. I'm glad the screws did their job, though. Just take your time getting out any broken screw pieces. That's the only downside to nylon screws. Damn, bro! You WILL get this. I'm certain of it!

Scott

As a matter of fact the screws came right out. I used 30mm ones so I had some sticking out the other side. I just losened the support bolts up, flipped the mounts and unscrewed them. Easy peezy.

[dankcincy]

Ive talked to a couple of people and they have agreed that grounding the boom may be a good idea.
Yes, static hits to the VBar or the metal cased tail servo may very well be the culprit.
I can tell you this though, I didnt brown out. Gotta love Airtronics!!!

[dankcincy]

Originally Posted by dankcincy

I almost saved it this time though. I had it 2ft off the ground, hit TH and then something goofy happened and it slammed into the ground. More of a hard landing then anything I would say.

I love big sky fishing!!!
(Yes, I just quoted my own post)

[Ah Clem]

Regarding grounding the boom. I had static issues on a belted Trex 600E and later on with my 6HV.

It was fairly sporting on the Trex, which was flybarred, but when the static hit the V-Barred FBL 6HV, is was quite impressive. I have never seen any helicopter move that quickly (but, or course, not when I wanted it to).

Grounded the boom to the motor mount and no problems.

The 7HV should have come with a ground wire (at least mine did).

Myrseth, by the way, is absolutely brilliant on the V-Bar (although he will not admit it). He helped me more than I can describe when I first got mine!