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Old 11-21-2020, 01:54 PM   #1 (permalink)
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Default 450 feels underpowered

So I've got a 450 clone that I've been working on for a while now, and she just doesn't have that "pop" I see from the crazy 3d helicopters.

I'm running a savox 3500kv on 3s with a cc lite 50. I think the main gear is 150T, and I've now tried 13, 14, and 15T pinions to try and get the headspeed up.

I'm also using a ikon 2 fbl unit.

I've tried using the ikon's governor, based on what the cc esc says it can govern properly. Eg, if the castle link software says it can govern 2800 rpm, I set one of the headspeeds on the ikon to that.

Unfortunately, I'm getting bad tail behavior using the ikon governor. Specifically, I get this tail wobble, especially if the helicopter gets hit with some wind. I say wobble because it's lower frequency than the wag you get from too high gain.

Two things I haven't tried to remedy this 1) drop the ikon governor gain and 2) increase the mechanical gain by moving out the servo ball on the tail horn.

What I have tried is just turning the ikon governor off and running flat TC's at 80, 90, and 100% throttle. I worry that, with the 15t gear, this might be hard on the batteries, but idk.

Running flat curves seems to improve the tail wobble issue, but even at 100% throttle it doesn't have that 3d "pop," and I'm not sure why (and yes I'm running full pitch, +/-12 deg).

One thing to note - I'm at 7000 ft, which may be part of the problem.

But I want to know if there's something else going on, or just in general I'd like to learn more about how to optimize this setup.

Happy to answer questions. Thanks!
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Old 11-21-2020, 02:14 PM   #2 (permalink)
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Batteries ? Mah, new, old ?

You have to use only ONE governor. If using the Castle all you do on the iKon is set the limits.

Tail wobble or wonder is usually due to low HS (poor tail authority).

IIRC 150-T main goes with 13T pinion just fine.
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Old 11-21-2020, 02:36 PM   #3 (permalink)
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I'm using these batteries. New, only months old.

I am using only one governor. Either I'm using the Ikon governor with the CC in external governor mode, or the CC in fixed endpoints mode with the Ikon governor off. I haven't experimented with the CC governor.

I just feel like I was having trouble getting the headspeeds I need out of 13Tx150T for performance/light 3D flight?

That being said, I've read that the CC software is conservative about what it can govern, and that apparently it will govern up to 103% throttle without issue.
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Old 11-21-2020, 03:32 PM   #4 (permalink)
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Just use the cc governor. It’s a good one.

Tail set-up mechanically with 2 degrees right pitch, servo neutral and properly selected in software, frequency/hertz.

Check your deadband, one size larger tail blades. Tighten “I” setting on tail.

Tail should snap to a stop. Once you have the tail holding correctly,
13 degrees of pitch.
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Old 11-21-2020, 06:05 PM   #5 (permalink)
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Quote:
Originally Posted by Tomstoy2 View Post
Just use the cc governor. Itís a good one.

Tail set-up mechanically with 2 degrees right pitch, servo neutral and properly selected in software, frequency/hertz.

Check your deadband, one size larger tail blades. Tighten ďIĒ setting on tail.

Tail should snap to a stop. Once you have the tail holding correctly,
13 degrees of pitch.
When you say "tighten" I do you mean increase or decrease the integral gain on the tail?

And are you talking 13 degrees pitch on the tail or the main rotor? I'm guessing main rotors, the more I think about it.
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Old 11-21-2020, 07:42 PM   #6 (permalink)
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Stick with the castle governor to start until you get things tuned. It will be easier to get working correctly right off the bench. Once you get everything else how you like, and think you need to switch to the ikon gov then switch.

Have you tach'd it yet? If not and you don't have one, there is an iPhone app called rc heli headspeed. You can hover over your phone and it will get you reasonably close to what headspeed you are running. You'll want to get an idea of what kind of headspeed that you are running, as it will help both you and others help you get to the bottom of your issue.

I'm assuming you're running 325mm blades. When I flew Trex 450's I would run around 3000-3200 for 3d flying, and it had that "pop" you are describing. Flying at 7,000' will absolutely be a factor, you have considerably less air for the blades to grab onto. Compensating with more headspeed/pitch may be necessary.

I think a good next step would be to figure out what headspeed you are actually running. If it is not reaching a reasonable one, then we can look into what could be causing that. It is important to get the headspeed issue figured out before dialing in the tail, unless the tail is practically un-flyable, because fluctuating/improper headspeed is just going to make it a pain to tune the tail.
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Old 11-21-2020, 10:00 PM   #7 (permalink)
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Quote:
Originally Posted by Dylan Hudock View Post

I'm assuming you're running 325mm blades. When I flew Trex 450's I would run around 3000-3200 for 3d flying, and it had that "pop" you are describing. Flying at 7,000' will absolutely be a factor, you have considerably less air for the blades to grab onto. Compensating with more headspeed/pitch may be necessary.
this!

I havent flown a 450 in 5 years or so, but i was flying 3500rpm to get it to pop, and I'm at sea level. at 7000' you're at a disadvantage, but still doable. but, you're going to need to get the RPMs up.
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Old 11-22-2020, 09:16 AM   #8 (permalink)
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Quote:
Originally Posted by PancakeMSTR View Post
When you say "tighten" I do you mean increase or decrease the integral gain on the tail?
Increase, until you have a crispy tail with no bounce back,

Quote:
And are you talking 13 degrees pitch on the tail or the main rotor? I'm guessing main rotors, the more I think about it.
That's main blade collective pitch, you may also want to check your cyclic pitch. Some FBL's require a bit right offset on tail, that's what he means by the 2 dg. right on neutral. Your tail pitch is according to slider travel extent and how you like your piro's. Sometimes too much travel can lead to dog bone lock, so you may want to pay attention to the sliders' extreme positions.
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Old 11-22-2020, 10:17 AM   #9 (permalink)
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3s setup is ok but that's like the old days, but still works You want more pop you need go go like 4s or 6s and stretch it to 360-380. Battery fit might be a problem. Back then a good 3d hs for the 450 is like 3200+. Try 4s and get a 3000kv motor or even a little less. Try 13 pitch or a little more. Good tail starts with smooth mechanics, make sure all parts are smooth. Find that sweet spot tail gain before oscillation, then back off about 1/3, increase Igain after that. You might want to visit the brain forum for the tweaking guide. I still love the 450 and acutually working on reviving one of it right now
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Old 11-22-2020, 10:20 AM   #10 (permalink)
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Honestly, first thing I’d do is upload your data in a flight calculator, like RC heli toolbox, ( free ), and see what your max head speed can be.
Then I’d input 80% and 100% into the cc governor what the calculator rpm would be for those values.
Next, I’d go one size larger on the tail blades, and as large main blades as will fit, something with a lot of lift like Switch blades.
That ought to get it in the ballpark for your altitude.
Gains should drop back to what you’re use to.
After that you can fine tune the tail performance in pid settings. The help menu does a good job walking you thru what each does. You can experiment here, set one bank where the presets haven’t been changed and another bank altered. Then in flight you can flip to the bank you did changes to and make in-flight comparison.

I’m at 5000 feet here, but that extra 2000 feet makes a huge difference. That’s why I recommend 13 degrees pitch. The blades will bitch about it loudly, but you got to max the pitch.

After that she ought to be able to do what you want, abet a little slower in the reaction so be aware.
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Old 11-22-2020, 01:03 PM   #11 (permalink)
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Thanks for all the advice everyone, will definitely try them out.

- I'll switch to using the castle governor.

- I'll give the tail a couple degrees pitch at neutral

- I likely won't stretch the heli to a larger size, mainly because I'm planning on building a 380 soon.

- I may try better blades, though, e.g. switchblades? I'll look into that.

Thanks a bunch, keep suggestions coming, happy to hear them all.

By the way - I tried this IRCHA toolbox app (3500kV 3S 150:15), which puts me at 3444 RPM at 80% Throttle, and....4305 RPM at 100%...which seems "break the helicopter apart" high. So what I'll do is probably try to tell the CC to govern at 3400, 3500, and 3700 maybe, and see how it behaves. Maybe tach it to see if it's actually reaching those RPMs. If it gives me better results, I might step down the gearing to make life easier on the battery.
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Old 11-22-2020, 05:47 PM   #12 (permalink)
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You got the idea!

Honestly, just changing the tail blades will probably bring her back just fine with no other need but to reset your gain.

The problem is (a), if this is a Trex kit they are infamous for low tail ratio.
(B), air density means your moving less air.
Larger tail blades address both issues.

Don’t stretch her. There are so much better heli’s out there now.
I personally recommend a Oxy4 max in the 380 range. You’d be hard pressed to find better!
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Old 11-22-2020, 06:35 PM   #13 (permalink)
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It's not a Trex kit, but it is a clone. I would be surprised if it wasn't using the Trex ratios.

What size tail blades do you recommend? In fact, could you suggest some specific tail blades? I have nice 62 mm carbon fiber ones on but I'm not sure if that's long enough.

Oh and, any advice on how to set tail pitch? I've done it on the main blades but I'm not sure how to do it accurately on the tail.

I've got my heart pretty set on a SAB 380, though the Oxys do make a strong case.

That aside, I agree with you, the 450 range seems sort of dead. The only reason I'm using this one is because I had already built it earlier last decade and it had just been sitting around waiting to be picked up again - it wasn't a recent purchase.
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Old 11-22-2020, 07:01 PM   #14 (permalink)
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62mm seems a tad small, actually. Most 450’s are 63mm. I’d look for 63-64mm, plastic is fine, save your money.

As far as the tail throws are concerned. All that is done in the setup screens in the Ikon2.
The main thing is once you have the 2 degrees right pitch set mechanically, you then adjust throws as described in the help menu. The main thing here is that you left/right throw numbers should be somewhat equal.
Also, setting your tail servo selection in Ikon2 is critical. Make sure your servo settings match what’s on the screen. Such as 1520/333. Look up your tail servo values and enter them.

The Oxy builds lighter than the Sab. At 7000 feet weight is critical.
My Oxy comes in at all up weight if 1.5 pounds!

My 450 is what I learned to fly on and still flys well today! So I understand the desire to keep an old bird operating.
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Old 11-22-2020, 08:19 PM   #15 (permalink)
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Weirdly hard to find some longer 450 size tail blades, but I managed it.

It's mechanically setting up the 2 degrees positive (?) pitch on the tail at neutral that I'm not sure how to do, except other than by eye, and is what I'm looking for suggestions on. I'm comfortable once I get into the ikon software, and I've got the throws and servos configured correctly, as far as I can tell.

I've heard SABs build a little heavy, but there are other considerations that make me attracted to them over Oxys (and other brands). We'll see if I decide my choice ends up being a mistake in the future. Fortunately, I'm only shooting for light 3D at the most (borderline even less than that, I want to be able to flip and roll the helicopter, maybe fly it upside down, but that's it), rather than Tareq Alsaadi level acrobatics. This thread is mostly about, in general, just learning I guess? Get questions I have answered?

Thanks for the help btw! Much appreciated.
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Old 11-22-2020, 08:22 PM   #16 (permalink)
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I would try to find a small 4s pack that would fit and try it; as mentioned, that
dang "density altitude".....

Fly a 4s in my Oxy 4M, and it flys so sweet, and of course, that is a bit bigger than what you are flying, so you should have some nice power to overcome that elevation, especially tying that in w. 13ish pitch that was recommended.

That is, if your esc can handle bit more voltage......
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Old 11-22-2020, 09:00 PM   #17 (permalink)
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Yeah 4s seems interesting, I may indeed try that. Is that ok with the 3500kV motor? My ESC should be fine, it's rated up to 8s.
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Old 11-22-2020, 09:12 PM   #18 (permalink)
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You’ll need to look up your motor’s rating.
Old 450’s in the 3s range were pretty specific back then.

Nothing wrong with 3s though. 4s would be better, I agree, but why bother?
Best save the money for the 380. The kit is just half the cost! Servo’s ain’t cheap.
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Old 11-22-2020, 09:39 PM   #19 (permalink)
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Quote:
Originally Posted by PancakeMSTR View Post
Yeah 4s seems interesting, I may indeed try that. Is that ok with the 3500kV motor? My ESC should be fine, it's rated up to 8s.
You are limited to 10T or 11T and your main gear might strip easy. Best to use a 2900-3000kv so you can use bigger pinion.
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Old 11-23-2020, 01:18 AM   #20 (permalink)
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Quote:
Originally Posted by Tomstoy2 View Post
4s would be better, I agree, but why bother?
Best save the money for the 380. The kit is just half the cost! Servoís ainít cheap.
Good point. I think I'll get the 450 tuned as best I can as it is, and save real upgrades for the 380.
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