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jstarks
07-27-2011, 07:34 AM
Having problems with the tail not having enough power.

A little history on my set up:
Logo 600 3D
12s 3300, Jive 80HV, Xera 4030-3Y, 8717cyclic/8900tail, mini vbar, 623 Edge FBL mains, 95 Edge tail.
Normal 1500
IU1 2000
IU2 2150

When I first set this machine up, I was using a Beastx with 603s and 95s, then switched to 623s. The tail never felt totally "locked in" so, I put the QUK tail on it and switched to 105s. The tail got better but, still wasn't what I sthought it should be. On moves where the collective would change quickly from positive to negative (or negative to positive) the tail would kick out, by as much as 30 degrees with the 95s but less with the 105s.
I then switched to a mini vbar thinking that the extra tail tunability would allow me to get rid of this problem; and it did!! No more kick out, no nothing, just fly it!!! Well....I had to go and mess with it.:roll:
I was thinking that I could increase my flight times by going back to the 95mm tails because, it has to take more energy to run the 105s, and with the tunability I should be able to get a solid tail with 95s, even though I'm running 623 mains, right?:confused:

Now with the 95s back on there it is almost unflyable!
When making a long, high speed, banking turn to the right (nose right), half way thru the turn the tail will literally stop coming around, like it just stalls out!:wow2: Same scenario to the left doesn't do it.
Same thing when doing FFF and then piro, nose left is somewhat ok but, nose right the tail will struggle going into the wind and then slingshot around.
When coming from FFF into an aggressive half piro flip(nose left), the tail will struggle and then whip around.
All of this was happening with:
Gain settings between 90 and 100 in vbar.
Tail endpoints at 105ccw and 120cw (thinking I may need to go out a hole on the horn?)
Yaw rate 100
RC Deadband 5, Acceleration 75, P 70, I 75, Stop A 25, Stop B 20.
Precomp - 18 collective, 8 cyclic

My next step is to put the stock tail back on with the 95s (elliminate possible geometry issues with the QUK tail which could have been masked by the 105s?) and go back to stock tail settings in vbar and start over.:arggg:

If you are running 623 mains with 95mm tails, without any of the issues I have described , please post your settings. I would really like to make this work, rather than just putting the 105s back on and calling it good!

Thanks in advance for any help,:thumbup:

J.

Nko15
07-27-2011, 07:41 AM
try some more precomp to get the tail stop kicking in the pitch reverals. maybe get the endpoints the same left/right to get the best geometry.

sgrim80
07-27-2011, 11:36 AM
The JIVE gov will make the tail kick a bit too, not much you can do about that. Your vbar settings look good, I'm not sure you'll save much flight time switching to 95s. Why not just run 105s and call it a day?

jstarks
07-27-2011, 12:26 PM
maybe get the endpoints the same left/right to get the best geometry.

Which is more important, getting the endpoints the same left/right or getting the 2-3 degrees of pitch in the tail blades against torque, as stated in vbar?
Because I can not get both. If I set equal endpoints, I have a whole lot of pitch in the tail blades.

The JIVE gov will make the tail kick a bit too, not much you can do about that. Your vbar settings look good, I'm not sure you'll save much flight time switching to 95s. Why not just run 105s and call it a day?

That may be what I end up doing. I just thought that there might be someone out there that has had good results with the 623/95 combo.
Just like it takes more power to spin the larger mains, it's bound to take more power to spin the larger tails and that power has to come from the packs. Just trying to get the best performance, for the set-up that I have. The difference between the 95s and 105s is substantial because they are not just longer but have a wider chord also.

Seems like with all the "in between" blade sizes like 615, 620, 630 and so on, they would make an in between tail blade like a 100mm.:dontknow

Thanks for the responses; still hope someone is running this combo with success and gives me some ideas.

J.

marcosp
07-27-2011, 12:36 PM
I am. On 2150 I had problems too, even on 603s. You really need 2200 or more to get the tail solid on demanding maneuvers.

With the horn at 90 and the tail lever at 90 I had the endpoints on the V-Bar not equal, something like 130 and 80. Last weekend I moved the horn one spline forward and re did the pushrod to get around 110/110. Also went out one hole on the horn. These were recommendations by Dave Dahl. They worked wonderfully even on stock settings 80/60 P and I. I have banks 1 and 2 on 75/65 and 75/75 still to keep trying them and find which one I like more. Of course I had to lower the gain to 70 with the longer servo arm but the tile is really solid now. After setting this up you'll find the pitch at 90 is almost cero, which is not ideal in my book but the fact is it works. My pre comp ended in 20, tried 22 and 18, found 20 to be the sweet spot. The pre comp is working much better now as well, still a little kick from the Jive Gov but much better than before. Seems like the geometry works better now than before.

Make sure you use absolutely all the throw on both directions even if the blades look like they have too much pitch. There is still a little weathervaning on left piros when going against the wind, on piro FFF or on piro funnels, though this can be improved with a little higher acceleration, I went from stock to 65 and 75. I am liking 75.

marcosp
07-27-2011, 12:41 PM
Oh, the 623s do put a stress on 3300 and the heli feels a bit light. I maidened new 3850s with the 623s and recovered my 5 min flights at 2250. And boy do the 65C put out power!!!

sgrim80
07-27-2011, 01:15 PM
Oh, the 623s do put a stress on 3300 and the heli feels a bit light. I maidened new 3850s with the 623s and recovered my 5 min flights at 2250. And boy do the 65C put out power!!!

Quick UK tail and 105s?

Ah Clem
07-27-2011, 01:20 PM
I am running 615's with 96mm tail blades (KBDD EE's) and have plenty of power on the tail.

kouasupra
07-27-2011, 03:56 PM
Kyle Dahl, and Jesse K are running 623mm with 95mm tail blades. On another note, I'm running the same setup without a problem, but I'm running the stock mikado tail grip. The quick uk tail grip doesn't have the right geometry.

marcosp
07-27-2011, 06:49 PM
Quick UK tail and 105s?

Standard tail and 95s which was the question of the thread.

jstarks
07-27-2011, 08:50 PM
Thanks for all the replies,

For now I am going to just put the 105s back on until I can get some parts.
I'm gonna get a new pitch slider and bushing to use with the stock tail so that I can have a complete unit to swap with the QUK one, instead of having to remove the bushing from the yoke repeatedly while I'm swapping tail systems back and forth.

I'll let y'all know what I end up with!

Thanks again,

J.

don-dadda
07-27-2011, 10:14 PM
Which QuickUK tail are you using? Is it an older one without the offset? I tried an older set without the offset and experienced the same thing you are describing with 95mm blades. The geometry on the grips without the offset dont give you equal travel so when the tail pitch lever is at 90 degrees there is not enough pitch in the tailblades. My endpoints were something like 85 - 140. The tail was really unpredicatable with this setup.

kouasupra
07-28-2011, 12:35 AM
I have one of the new quick uk tail grip and on stall turns CCW rudder gets stuck. 105 with quick uk is okay, but isn't as good as the stock tail grip with 95mm blades. I installing back the stock tail grip it was much better.

jstarks
07-28-2011, 01:47 PM
Which QuickUK tail are you using? Is it an older one without the offset? I tried an older set without the offset and experienced the same thing you are describing with 95mm blades. The geometry on the grips without the offset dont give you equal travel so when the tail pitch lever is at 90 degrees there is not enough pitch in the tailblades. My endpoints were something like 85 - 140. The tail was really unpredicatable with this setup.

I bought the QUK tail from RH a few months ago. It does have an off-set but, not as much as the stock tail.

Going back to 105s til my parts come in, then I'll do some swapping and adjusting.

prototype3a
07-28-2011, 03:11 PM
Yes. However, I'm cheating...

http://static.rcgroups.net/forums/attachments/3/6/8/6/5/9/a4163364-57-DPP_0011.jpg

jstarks
07-28-2011, 03:46 PM
:rotf
Yeah I would say that the extra tail blade definitely is cheating!

You should have an amazing amount of tail authority!

J.

prototype3a
07-28-2011, 04:03 PM
I initially tried that same tail unit with the sk720 and they didn't get along very well but the v-bar loves it with more or less stock settings!

wlfk
07-29-2011, 01:32 AM
What's the 3 blade tail unit?

I'm currently running 1000rpm with a view to getting longer flight times. For my style of flying it works, but even with 105mm tail blades, I lose the tail if I hit full collective. I was wondering the other day whether a higher solidity tail (more blade area) might help.

Nko15
07-29-2011, 02:51 AM
What's the 3 blade tail unit?


I2rc i tought...:thumbup:

wlfk
07-29-2011, 06:22 AM
Lovely looking bit of equipment, but a bit expensive for me alas.

jstarks
07-29-2011, 07:11 PM
Ok. Went back to 105s and the tail is working wonderful again!!! :lol:

As soon as my new slider comes in, I'll assemble the stock tail and try the 95s again and post back, if I have trouble.

wlfk
07-29-2011, 07:28 PM
..

wlfk
07-29-2011, 07:30 PM
Just a thought - going back to the original question.

You want the smaller blades in order to get longer flight times. Interestingly, when I changed from cheap 95mm blades to edge 105mm blades, my flight times increased by a minute or two. I was very surprised and at some point I'm going to go back and check that it actually was the blades that made such a difference.

That said, they say that tails take up from 10% to 20% of the total power of the helicopter - most sources give more like 10%. Seems to me that proportionally speaking it's probably not worthwhile going on too much of a crusade for a smaller tail. Have you checked flight times with the 2 different size blades?

jstarks
07-29-2011, 07:43 PM
Hmmm.....well that's very interesting.

I was just thinking that the larger blades took more power but, I guess that once they are at speed they have to deflect less to move the same amount of air as the 95s so they may actually be more efficient. :dontknow

I already ordered the new slider so I will go ahead as planned and assemble the stock tail with 95s. Then it will just be a matter of removing the grub screw and swapping it for the QUK tail with the105s. I'm actually anxious to see what the outcome will be.

I gotta say that it was weird and scary when I made that first high speed turn and the tail just stopped coming around, like it hit a wall!:wow2:

J.

wlfk
07-29-2011, 07:52 PM
I think that, theoretically, it should be the case that larger blades will take more power, despite being able to make do with a lower angle of attack. It might just have been that my edge 105 blades were more efficient than the cheaper blades, and that if I'd used edge 95mm blades my flying times would have been longer again...