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HomeAircraftHelicopterAlignOther › program mix
03-07-2008 02:17 PM  10 years agoPost 21
Simmer

rrElite Veteran

Massachusetts

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Brcg123,

Whats you flying level? if you just tooling around, why add in a mix? just cause its there? The mix is effective for tweaking and having it fly more consistant, if you are planning on running a gov, and using it 98% of the time, dont add any mix. If you are not running a gov, by all means add the mix. If you have enough flight modes, set up one with the mix to play around and dont bother in the mode that has the gov enabled. its pointless in my opinion if you running a gov.

For instance, I have a gov and I plan to use it except when I take off (normal mode) and sometimes I land in normal, though not always. A mix would be benficial only during those two times for me. IN an Auto it wont help. so for me ... pointless.

If you do plan to fly around with the gov disabled or just wish to play with it , have at it. It is a good thing to set up you heli to fly without gov. Especially wen tuning an engine (as I am currently dealing with )
I use normal mode to check tune my engine, but I just wouldnt fly around in normal for most any other reason.

Your throttle mix's are to compensate for engine rpm changes with regard to making turns against or with the engine torque, and preceeding, lagging balde effects on the flight envelope.

You will appreciate your gov when you get it installed. I suspect you wont want to "fly around" without it on once you use it.

You are probably already making corrections when you fly without the gov now. Adding more rudder, more or less aileron when you turn and increasing the throttle when making a tight turn.

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03-07-2008 02:53 PM  10 years agoPost 22
brcg123

rrKey Veteran

Wagoner OK USA

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Ive been flying for 3 years now and I'm just at the threshold of loops rolls ,and general sport flying. i just bought the throttle jockey pro and i have it installed with the atv's at 0, so it wont engage until i get to the Field tomorrow and have help with tach. I have been flying without gov. all this time so I'm at peace with setting curves up. Since i like to nose in hover and play around up close as well as looping and rolling, i figured i need some sort of kick as well as the gov. for constant head speed and no over speeding on decent. i take off in ST1 and try to land in auto or ST1.once i hookup the TJ pro, i plan on running around 1800 in norm and 2000 in ST1. so if I'm flying around, as such, i have my throttle curves set with the TJpro set to the specs, it should take care of both styles of flying, giving me constant head speeds and "goosing" the engine for ail and ele if the rpms drop, without the mixes?








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03-07-2008 03:36 PM  10 years agoPost 23
nivlek

rrProfessor

Norfolk England

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if you pirio with the rotation of the main rotor, (clockwise) wont the GOV see this as a drop in RPMs
Yes , but your piro rate is low enough not to make any noticable difference - unless you're using a JR gyro with the end points set to 150 !

With the TJ you don't need to use throttle mixing , but apparently the TJ does "look" at the receivers throttle output and uses it to "predict" likely changes required to speed up its response time , so mixing can help in this respect .

At the end of the day , it gets dark .

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03-07-2008 03:55 PM  10 years agoPost 24
cbflys

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Nesconset, NY - USA

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I'm trying to make sense of what was said here. I'd like to offer my simplistic view on this subject.

The original question I believe was "should you use RUD->THR mix?". I think the answer to that is "it depends". What it depends on is if you run a govenor or throttle limiter. In that case, the answer is no. you don't need any control to throttle mixing at all.

If you're running throttle curves, then the answer is yes. Regardless of whether you have a HH gyro or not. The gyro's job is to keep the heli pointing in the same heading when there is no rudder control input. With rudder control input it controls the rate of turn based on the amount of control input. There is no feedback into the engine/head speed. So assuming there is no input other than rudder, the heli will decend with rudder input in one direction and assend with rudder input in the other. RUD->THR mix WILL correct this. More throttle in one direction and less in the other.

Now, the other question is whether or not this is REALLY necessary. One could argue that you can compensate with you piloting skills. And you can. But the fact is, the mixing will help if applied correctly.

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03-07-2008 05:10 PM  10 years agoPost 25
brcg123

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Wagoner OK USA

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ok, i understand now thanks everyone for your input, cbflys, you've convinced me, no mix. thanks








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03-07-2008 05:36 PM  10 years agoPost 26
jackheli

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Vancouver - Canada

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I flew my T600N on this same exact setup while I was waiting for my metal fan (the plastic fan decapitated my governor sensor). You couldn't quite tell there was no governor on. Just a slight over rev on quick unloads and that was it.

All possible 3D stunts with 25% mix on cyclics to throttle and no mix on rudder to throttle: didn't find it necessary (and 2% in practice won't make absolutely any difference anyways)

One thing you have to be VERY careful, though, is to be sure your throttle servo DOES NOT BIND. Depending on how your transmitter operates it will add the mix ON TOP of your ATVs. What this means is that if you set your servo throttle travel so it works perfectly with the collective stick the mix my push the servo OVER the top end limit when it is close to fully open and you give it a cyclic command.

In order to prevent the bind you can either program a true limit on your transmitter if it carries this function, or you can spring load the throttle link rod.

It's easy to find an excuse to do wrong. Hard is not to find an excuse to do right.

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03-07-2008 05:39 PM  10 years agoPost 27
nivlek

rrProfessor

Norfolk England

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In order to prevent that you can either program a true limit on your transmitter if it carries this function, or you can spring load the throttle link rod.
If you set full throttle with maximum subtrim (or maximum travel adjust) it won't be able to go any further .

At the end of the day , it gets dark .

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03-07-2008 05:42 PM  10 years agoPost 28
cbflys

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Nesconset, NY - USA

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One thing you have to be VERY careful, though, is to be sure your throttle servo DOES NOT BIND. Depending on how your transmitter operates it will add the mix ON TOP of your ATVs.
This is a very good point, as most systems do operate this way.

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03-07-2008 05:46 PM  10 years agoPost 29
jackheli

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Vancouver - Canada

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If you set full throttle with maximum subtrim (or maximum travel adjust) it won't be able to go any further .
Yes, can do that also. What I don't like about this approach is that it makes for very difficult throttle arm adjustments.

If you are not running a governor you are relying exclusively on your curves and mixes to get a consistent RPM. That being said, the ONLY way to be able to adjust anything is if you maintain the symmetry of your setup, with the engine throttle arm parallel to the servo arm AT ALL TIMES and half way on the barrel at mid stick. This is VERY difficult to achieve if you are messing around with subtrims, but I guess it is possible.

It's easy to find an excuse to do wrong. Hard is not to find an excuse to do right.

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03-07-2008 05:56 PM  10 years agoPost 30
nivlek

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Norfolk England

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This is VERY difficult to achieve if you are messing around with subtrims, but I guess it is possible.
I never found it difficult , but I came from an age before travel adjust and subtrim or even servo reverse, when all you had was mechanical setup !

At the end of the day , it gets dark .

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03-07-2008 08:44 PM  10 years agoPost 31
brcg123

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Wagoner OK USA

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i got all these ideas from watching Ray Hostetler set up video from god only knows when, and it says to put ail-thro +20, -20 ele.-thro +20,-20 and rudd-thro -8,-8 and to put the thro down to 90% at the top and it wouldnt bind, and you get full throttle. when testing, he adjusted rudd to -2,-2 and no overspeeding, it was cool how it all came together, so i thought i would give it a try, thought about it anyway, i dont want to have to mess with the throttle linkage at all. it is perfect where it is. if i have to start changing stuff, then im bailing on that idea! im going to run the Throttle jockey Pro so it sounds like the gov is going to over ride the mix, and i dont think the gov will let me stop at 90%, will it? so i would have to change the linkage if i couldn't. Ray started all this.








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03-07-2008 08:55 PM  10 years agoPost 32
cbflys

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Nesconset, NY - USA

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As mentioned before, if you run a limiter - then you don't need any mixing to the throttle. The limiter will make sure your headspeed stays constant (as long as the engine has enough omph), regardless of the aerodynamic load.

You don't have to worry about binding the throttle servo either, because the limiter stores your endpoint adjustments during calibration and will not drive the throttle servo past those points.

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03-07-2008 08:57 PM  10 years agoPost 33
jackheli

rrProfessor

Vancouver - Canada

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If you are thinking about running a governor forget about all this stuff.

Just put very basic backup curves, no mixes or anything, enough so that the bird doesn't fall from the skies on the event of a governor failure... which WILL actually happen if you leave that plastic fan mounted.

It's easy to find an excuse to do wrong. Hard is not to find an excuse to do right.

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03-07-2008 09:00 PM  10 years agoPost 34
jackheli

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Vancouver - Canada

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As mentioned before, if you run a limiter - then you don't need any mixing to the throttle. The limiter will make sure your headspeed stays constant (as long as the engine has enough omph), regardless of the aerodynamic load.
I am sorry sir, but this is sooo wrong. It makes sense for a governor, but if you mean a limiter then you have no idea how a limiter is supposed to be used going with straight 100% curves.

It's easy to find an excuse to do wrong. Hard is not to find an excuse to do right.

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03-07-2008 09:07 PM  10 years agoPost 35
brcg123

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Wagoner OK USA

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a limiter is not the same thing as a gov, is it?








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03-07-2008 09:19 PM  10 years agoPost 36
cbflys

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Nesconset, NY - USA

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I am sorry sir, but this is sooo wrong. It makes sense for a governor, but if you mean a limiter then you have no idea how a limiter is supposed to be used going with straight 100% curves.
I'm always looking for an education. I've used limiters with 100% throttle across the board. The limiter does all the work, no control to throttle mixing whatsoever. Headspeed stays at the target RPM (unless as I said, 100% throttle just isn't enough), which you get by using aggressive pitch at the ends.

So what am I missing here?

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03-07-2008 09:23 PM  10 years agoPost 37
jackheli

rrProfessor

Vancouver - Canada

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a limiter is not the same thing as a gov, is it?
No, it is not.

The governor provides acceleration and deceleration to the engine completely taking control while the limiter only provides deceleration while you provide the acceleration.

The idea behind the limiter is to reduce the amount of lag it takes a governor in order to sense there is an rpm change and act.

This is how a governor works: in a scenario where you add collective or cyclic the engine will load and reduce rpm, the governor sensor will detect the speed down and act on throttle. That takes time.

On a limiter, AS you add collective or cyclic you also command the throttle servo to open the barrel via curves or mixes. So the barrel opens at the same time the loading command is executed. The limiter only acts when you UNLOAD the engine and it may overspeed. Most of us can live with some minor lag on overspeed, but not on underspeed.

If you run straight 100% curves on a limiter like many do you are just running it like any other governor, without the actual "learning" algorithms governors have. Why? because the limiter will be ALWAYS limiting and will only stop limiting and allowing the 100% curve to take over and accelerate the engine when the blade loads, but by then it is too late and you have lag on acceleration.

Setup of a limiter is much more complicated since your curves and mixes need to be almost perfect, but it also has better response.

It's easy to find an excuse to do wrong. Hard is not to find an excuse to do right.

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03-07-2008 09:52 PM  10 years agoPost 38
cbflys

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Nesconset, NY - USA

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jackheli - I think we're in violent agreement here.

In fact, when using a limiter - I do set up my curves prior to activating it. A limiter will also work with 100% throttle curves. You are correct that when setup that way, it is ALWAYS limiting. But for most, this is acceptable.

What is commonly refered to as 'predictive' in my opionion is only realized by what you've already pointed out. The throttle servo is already moving by virtue of your control input BEFORE there is any change detected by the speed sensor.

The point I was trying to make was regarding control to throttle mixing - it is NOT needed with a limiter because the limiter will compensate. It is however useful by virtue of what I discussed above.

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03-07-2008 10:08 PM  10 years agoPost 39
jackheli

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Vancouver - Canada

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The point I was trying to make was regarding control to throttle mixing - it is NOT needed with a limiter because the limiter will compensate. It is however useful by virtue of what I discussed above.
Yes SIR!
The limiter will make sure your headspeed stays constant
This is what I have a problem with.

Anyways, running a limiter with 100% curve is a bad idea for two reasons:

1- The software is not the same as a governor, which as you said, tries to predict how to act on throttle based on past experience. Limiters are "limited" in their software because that is not their point.
2- If the sensor fails (and on a T-600 chances are EXTREMELY large that it WILL happen) your engine is doomed.

I personally have not used limiters so far, finding them a hassle just like you do
But for most, this is acceptable.
. I run straight governors, BUT it just happened that on my 600, BECAUSE of a sensor failure and having to wait for a part, I ended up going full way with mixes and curves, which ended up, lucky me, being VERY acceptable.

It's easy to find an excuse to do wrong. Hard is not to find an excuse to do right.

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03-07-2008 11:21 PM  10 years agoPost 40
Jafa

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Sydney, Australia

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As far as I am concerned this fear of running 100% throttle curves on limiters is irrational

When you have any device under silicon control you cannot predict the nature of potential failures. Remember the entire model is under silicon control, glitches and lockouts and failures occur, model hits the dirt, ouch and $$$. And you're worried about a $200 part? (the engine)

One of my flying buddies had a GV1 that would not not disengage after the magnet was thrown and reved the engine very hard - we never worked out why. So it can happen to any governor/limiter technology

I have three times engaged a 100% throttle curve without the RevMax being enabled - the biggest concern is the main blades throwing a lead weight (I've seen it happen), not the engine. Each time the engine reved out hard and suffered no damage, it is after all a 2 stroke

If you ever do have a limiter failure, you just switch back to normal mode, it's that easy. Even if you are inverted, it's still no problem, you hit full aileron at zero pitch and get her upright.

Many people like setting up curves and mixes, that's good stuff. But don't delude yourself that you can match the in flight performance of a governor or limiter, without one of these marvelous devices you cannot do a full power/collective decent without the headspeed overspeeding - it's a really simple example of curves not able to cater for all flight conditions


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