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  #16  
Old 06-04-2006, 06:38 PM
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Quote:
Originally Posted by nemo_uk
Hi opjose,

I changed it back because with the vertical moment the top part of the "gun" intersects with the front of the fuselage.

I need to tweak the model so that the parts rotate correctly/separately

Regards,

Tony
No problem... although I could merely lessen the degree of movement until they parts do not intersect, or just remove the verticle movement.

It does look rather cool though to see the gun moving all around while the heli is in flight.
  #17  
Old 06-04-2006, 06:54 PM
MaddSkillz MaddSkillz is offline
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Sweet! Just downloaded it and am about to fly it! Thanks!

MS
  #18  
Old 06-04-2006, 08:49 PM
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Two modifications...

The "dynamic guns" AV changes the control input to the guns so that when you move the tail (rudder input) the guns move as well. This makes the guns and pilot look along the line of intended travel.

The gun pitch only moves up and down slightly as you input pitch commands to the heli.

Nemo is right in that the gun movement looks a bit unrealistc due to an erroneous pivot, but it is barely noticible when you are not viewing the heli in the editor.


The second modification adds invisible "paddles" for those of us used to the unscalelike but more accurate Bell-Hiller mixing for RC copters.

This makes the heli easier to control, reduces uncommanded lateral movement, and prevents uncommanded pitch up in fast forward flight.

The visual model is not affected, so no one need know....
Attached Files
File Type: g3x Blue Thunder Dynamic Gun_AV.G3X (34.7 KB, 120 views)
File Type: g3x Blue Thunder with Paddles_AV.G3X (34.8 KB, 117 views)
  #19  
Old 06-04-2006, 08:59 PM
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i might try making a heli for g3 using rihno 3d. its not gonna be easy
  #20  
Old 06-05-2006, 11:13 AM
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This Heli is so cool....I'm speechless
  #21  
Old 06-05-2006, 11:21 AM
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This heli is acting very strange.

It looks awesome, and starts out okay. But it has almost no tail rotor authority. Once I get airborne, if I lower the throttle input it goes into a downward motion like a reverse climb. I cannot reduce power to land because if I reduce power via the throttle stick it accelerates toward the ground.

Also, the toggle switch that normally takes the rpm to full throttle or idle, has no master control over the throttle stick. Even with the toggle at idle I can throttle up with the stick.

The other heli's I have tried do not exhibit these tendencies. Have I done something weird to it? Or is it this way for everyone?
  #22  
Old 06-05-2006, 12:06 PM
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Hi Kmot,

There is something weird with regards the tail If you try and wait a bit till the head speed builds up and then loop it, on the way out of the loop you have no rudder authority as you described. I'll take a look at it and see if I can tweak anything.

I'm guessing it some combination of the rotor speeds vs. gyro

With regards to toggle switch thatís something I have not looked at.

Regards,

Tony
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  #23  
Old 06-05-2006, 02:57 PM
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Thanks for checking it out nemo!
  #24  
Old 06-05-2006, 03:56 PM
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Kmot: which version are you talking about?

It sounds like you are both talking about two entirely different things.


You should have plenty of tail authority at low speeds.

Nemo_uk:

The thing has stabilizing tail fins though and a large tail.

The tail fins and the large tail, stabilize the rudder in flight as the model hits certain speeds. The real things do this too.

Helis with large tails are only able to travel sideways (sideslip) until the speed at which the tail rotor cannot overcome the weathervaning of the tail itself.

e.g. the aerodynamic Comanche maxes out at 55mph.


This causes little or low tail authority at speed. e.g. the looping problem.

You'll notice that the heli has a more pronounced tendancy to face the direction of travel at speed.

When the tail "stalls" you have a lot of rudder authority. This is normal.



Kmot:

The throttle controls the heli pitch like a 3D heli, so if you lower the throttle it will indeed head downward, but this is normal for high rates on a heli.

Did you flip the three position switch down and try to decend?

Last edited by opjose; 06-05-2006 at 06:52 PM.
  #25  
Old 06-05-2006, 04:55 PM
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Quote:
Kmot: which version are you talking about?
So far, I have only flown the original version.

Quote:
Did you flip the three position switch down and try to decend?
Yes.
  #26  
Old 06-05-2006, 08:51 PM
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Quote:
Originally Posted by Kmot
This heli is acting very strange.

It looks awesome, and starts out okay. But it has almost no tail rotor authority.
I don't see this.

At low speeds it has a lot of tail rotor authority. Once it hits the point at which the tail is no longer "stalled" though you'll only get about 15 degrees off the axis of travel. That's how they really fly with those huge "rudders" sticking out the back.

Quote:
Originally Posted by Kmot

Once I get airborne, if I lower the throttle input it goes into a downward motion like a reverse climb.
Once the govenor kicks in (make sure that you hear the govenor latch into the right RPM rate before you take off!) lowering throttle past 50% inverts the rotor pitch.

This is a 3D heli, so this is perfectly normal.

If you lower the throttole the heli will head for the deck.

The idea is that you only use throttle less than 50% when the heli is inverted or having problems coming down in high winds.

Again this is normal.

Have you flown helis before, not to be disparaging, it's just that I'm trying to get a reference as to what you are talking about?

Quote:
Originally Posted by Kmot

I cannot reduce power to land because if I reduce power via the throttle stick it accelerates toward the ground.
Again you don't reduce "power" (there's a govenor keeping the power constant so to speak) you reduce blade pitch, but you have to be careful as if you lower it a tad too much the heli dives down because of the inverted pitch of the blades.


Quote:
Originally Posted by Kmot
Also, the toggle switch that normally takes the rpm to full throttle or idle, has no master control over the throttle stick. Even with the toggle at idle I can throttle up with the stick.

I don't see this.

When you flip the right shoulder switch up the engine goes into idle.

The blades are quite heavy so they spin for a good while. Since they spin because of inertia, you can increase the throttle and the heli will ascend until the blades loose power, at which point it begins to drop like a rock.

You CANNOT "throttle up" with the right shoulder switch flipped.

You CAN change the blade pitch however.

Again this is normal, and needed for autorotations.

Quote:
Originally Posted by Kmot

The other heli's I have tried do not exhibit these tendencies. Have I done something weird to it? Or is it this way for everyone?
First did you import it? (Just in case you unpacked the files...)

This heli does NOT have Bell-Hiller mixing!!

Let me say that again....

This heli does NOT have Bell-Hiller mixing!!
This heli does NOT have Bell-Hiller mixing!!
This heli does NOT have Bell-Hiller mixing!!

Bell Hiller is what we are all used to.

It flies like any "scale" heli that uses a "scale" rotor head.

Check out the Bell 222 in G3. This flies just like it.

The Bell has a CG which is a bit further back so it doesn't nose down as much, and it has a much more pronounced roll... but otherwise these two are almost identical.

They are MUCH harder to control than a standard RC heli.

I would love to see Nemo make a 2 bladed model of this heli with paddles for those of us used to Bell-Hiller mixing.

I've tried to model Bell-Hiller in the file above that has paddles.

You'll find that with paddles it's far more stable and behaves more like what you may be thinking it should... (but actually shouldn't because this is a scale head.)
  #27  
Old 06-05-2006, 10:05 PM
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I too have noticed the decrease of tail authority in hard collective changes. It has nothing to do with the bell/hiller non bell/hiller head as I have flown both in real life. If you limit the collective changes to about 3/4 and 1/4 as the max on the number 3 idle setting you won't have the tail bog. If you go over that the tail is overcome by the rotor and the heli begins to rotate. It acts like the gyro for the tail is not set high enough for the gain or maybe the max pitch on the tail rotor is not enough to counter the torque of the main rotor.
  #28  
Old 06-05-2006, 10:23 PM
the_avocet the_avocet is offline
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YES!

Thanks much! This is Exactly the heli I've been wanting to fly since.. well.. since the movie!

I love the way it flies. It feels heavy!

Great stuff!

(p.s. Yeah so my idea of 3d is up, down, and sideways.. so what?)




Av


"What is it with this 'heavy' you keep saying? Is there a problem with the gravitational pull of the Earth in 1985?"

Last edited by the_avocet; 06-05-2006 at 10:25 PM.
  #29  
Old 06-05-2006, 10:28 PM
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opjose opjose is offline
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Quote:
Originally Posted by L0stS0ul
I too have noticed the decrease of tail authority in hard collective changes. It has nothing to do with the bell/hiller non bell/hiller head as I have flown both in real life.
.
Never said it was due to the head.

Quote:
Originally Posted by L0stS0ul
If you limit the collective changes to about 3/4 and 1/4 as the max on the number 3 idle setting you won't have the tail bog. If you go over that the tail is overcome by the rotor and the heli begins to rotate. It acts like the gyro for the tail is not set high enough for the gain or maybe the max pitch on the tail rotor is not enough to counter the torque of the main rotor.
That's what I thought, so the first thing I tried was to increase the tail gain values, and this did not help.

But this is due to a combination of factors as far as I can see...

First there is the actual weather vaning effect. Pushing the heli sideways exhibits the point at which it will kick in.

Then there is the rate and heading hold gain. Nemo had set these quite high initially to overcome the spin up rotation.

In fact the spin up rotation is sooo high on this heli that I had to make the blades very heavy to compensate. They have rather large inertia... (switch the motor into idle to see this at work...) to make it easier to control.

(This is where the lack of Bell Hiller kicks in, the original model was very difficult to fly...)

This may make it difficult for the tail rotor to overcome the torque (excellent modeling by the KE staff btw... second order effects coming into play!!! Great math on the part of the programmers!) and hence all gyro effort is going into stabilizing the tail.

This is probably the single biggest culprit. And yeah the tail pitch is normally used to overcome this problem, but the vanes in the tail are already at a working maximum... good call here.

Once I get this ironed out I'll post another revised edit.

Finally there is what Kmot is talking about which is entirely different, and what I was addressing as well...


Namely he seems to be talking about negative pitch and how the heli decends.

That's a completely different ballgame altogether.
  #30  
Old 06-05-2006, 10:41 PM
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No, I have never flown a real r/c heli. Only the ones in G2 and G3 and not all of them either. I have gone from total crash retard to being able to lift off, hover, fly around, and land. Not always pretty, but I can do it. The new BT just acts different than any other heli I have tried in the sim. I downloaded it like all the other G3X files.

Sounds like it's all just me.
 

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