Tail blow out with 520 blades

[TT]

I noticed a problem with the tail blowing out in some energy-intensive maneuvers. I'm positive that this is due to the motor bogging (you can hear it in the air). I'm running 520mm RJX Flybarless blades, 15t pinion, VBar gov, stock ESC and motor, Torq 9188 tail servo, Hyperion 4200mah 6S 35C packs.

There is no binding in the tail, the VBar gov/ESC setup is correct, headspeed in idleup 2 is 2450. My packs are in good shape...just broken in...resistance around 12-16 ohms per pack. Packs come down pretty warm but not hot, not puffed...but I'm wondering if they're up to the task.

I just ordered some Edge 523 flybarless blades to see if these would be an improvement over the RJX blades. I think they will be a little more efficient.

Anyone else experience this?

I have been practicing with the 700E FBL heli set to 10 lbs. flying weight (my 'primary' heli) on Phoenix with no blow-out during anything I am able to throw at it. Ironically, when I switched to the 550E FBL heli I could duplicate the same tail blow-out (in the same maneuvers) that was happening on the real X5 FES.

I don't want the tail blowing out when I'm doing full-speed hurricanes on the deck!!!

[caralmar]

I've experienced this as well, my X5 almost decapitated me as a result! I've upped the gain on my gyro (Spartan Quark) and went to the Edge 523 blades (I'm flybarred). I now do fast backwards stuff far away from me! Maybe some good Edge CF tail blades would help?

[akamullen]

Originally Posted by caralmar

I've experienced this as well, my X5 almost decapitated me as a result! I've upped the gain on my gyro (Spartan Quark) and went to the Edge 523 blades (I'm flybarred). I now do fast backwards stuff far away from me! Maybe some good Edge CF tail blades would help?

The KBDD Tails also are a little bigger than stock, with about 5-10% more surface area. A cheaper alternative to the More expensive EDGE tails. Surface area will give a little more hold and authority, less blowing out.

[caralmar]

I tried the KBDD tails. They are also more flexible. At high headspeed, they flutter...didn't like that at all.

[TT]

Yikes!

I'm at 'just under wag' on my VBar tail gain. I thought about going with slightly longer tail blades at first but I really need to get rid of the bogging to solve the problem. I might have to reduce my pitch but I don't really want to. I love the punch it has now.

I'm not having the problem during fast backwards flight...but it could happen. What really makes it blow out is fast sideways flight. I like to do fast sideways on the deck at full pitch then roll to send the heli skyward and do some death spirals on the way up...then on the way down...then fly sideways the other direction and do the same thing. Similar to a skateboarder in a half-pipe. I also like to do sideways vertical figure 8s and square figure 8s. These are all a no-go until the problem is solved.

Did you find the Edge 523s to be more efficient than what you were using before? And what were you using before?

Thanks!

[akamullen]

Did not know about that. I have not tried them (I use EDGE 86 tails currently), but have sold a few sets of the KBDD tails and people seemed to like em. Never heard about a flutter.

[caralmar]

I have a set of the yellow ones (92mm from center of root to tip). They are 27mm in width. They flew fine in ID1 (90% flat curve w/ a 15T pinion). Soon as I hit ID2, they began to flutter... that just didn't feel right, so I went back to the stock blades until I order up some Edge tails. I think they're meant for a 600, which has lower head speed, and thus lower speed at the tail.

[akamullen]

Originally Posted by caralmar

I have a set of the yellow ones (92mm from center of root to tip). They are 27mm in width. They flew fine in ID1 (90% flat curve w/ a 15T pinion). Soon as I hit ID2, they began to flutter... that just didn't feel right, so I went back to the stock blades until I order up some Edge tails. I think they're meant for a 600, which has lower head speed, and thus lower speed at the tail.

The KBDD tails I was refering to for the X5 are 84.5mm and are just a tish bigger than the stockers. 92mm is quite big for the x5 I would think. With large tails like 92mm I would imagine your gain would have to be quite low do to the low resolution from larger tails. Edge tails are 86mm.

[caralmar]

Yeah, guess you're right... Was hoping they would work out on the X5 since I had a new set on hand.

[Matt Nasca]

The very first time I cranked a fast backwards hurricane the tail let go, with the Edge 523mm and 86mm blades. That was running a HS of 2200 with 90 VBar gain on a bls251.

Now with a HS of 2400 with 105 overall gain the tail holds quite nicely. 75,75,75 in the Vbar tail settings.

[akamullen]

Originally Posted by RadDuke

The very first time I cranked a fast backwards hurricane the tail let go, with the Edge 523mm and 86mm blades. That was running a HS of 2200 with 90 VBar gain on a bls251.

Now with a HS of 2400 with 105 overall gain the tail holds quite nicely. 75,75,75 in the Vbar tail settings.

Yep, Matt brings up another good point. Tail rotor speed will help on blow outs as well. So if you want to run low headspeeds 1900-2200 and do light to hard 3D, maybe look at grabbing some 90mm or 92mm tails to get a better hold on the tail.

My X5 is running 15T pinion at 100% (not sure what the headspeed is?), RJX 520 FBL mains, Edge tails, and a outrage 9188 tail servo. My tail holds extremely well.