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Jan 05, 2017, 02:38 PM
Registered User
Mike,

I think using stick switches is really how the KAPOW mix is intended to be implemented. You don't want to have to think about flipping switches - just push full down and it is activated.

Tom
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Jan 05, 2017, 03:41 PM
Registered User
I think Mike wants a switch to "arm" the Kapow so it doesn't get activated unintentionally. Maybe he likes going full on the sticks Just kidding.

To your point though I don't think anyone ever goes full down unless landing so an "arming" switch is unnecessary.

In OpenTX I would just create a logical switch for full down and add lines in the mixer for the Kapow. I suppose if I was careful I would pick the flight modes I would want to use these in, probably all he modes minus launch and zoom would add some margin of safety.

I know RC-SOAR uses a kapow flight mode but I wouldn't do it that way. Yes it means less lines in the mixer but it would be harder to fix aforementioned issues like aileron to flap interference.
Last edited by Bmwjoon; Jan 05, 2017 at 03:49 PM.
Jan 05, 2017, 04:51 PM
Registered Taranis User
Miami Mike's Avatar
Quote:
Originally Posted by Kiesling
Mike,

I think using stick switches is really how the KAPOW mix is intended to be implemented. You don't want to have to think about flipping switches - just push full down and it is activated.

Tom
That's fine. One of the reasons I love the Taranis is that you can make any control do anything you want, which means you don't need to be restricted by what someone else intended. If you have a Taranis and you prefer to activate Kapow with your elevator stick, no problem. It would be easier to program and I can see the advantage of not needing a safety arming feature.

But what I really wanted to show in the video was how I delayed my flaps by 100 milliseconds so that my ailerons could get past them and go all the way up. Can your radio do that?
Latest blog entry: Taranis: Aileron-To-Rudder Mix.
Jan 05, 2017, 06:00 PM
Registered User
Just because a radio can do something doesn't mean you should do it.

My radio has a delay function, but I have never had the need to use it.

Typically at the top of the launch you might use full down to initiate the zoom. So you wouldn't want the Kapow mix active then, but for all other flight modes I would think you would want it active.

What you don't want is a program that lets you accidently forget to make it active and not have it work when you need it to.

That is why I have my landing mode as the dominant mode so it is always available regardless of what mode I'm currently in. Typically this is helpful if something goes wrong on launch and you may need to slow the model down quickly and you forget to take off the launch mode.

While the situation when you use the Kapow mix should be more controlled, sometimes strange things happen. . .

Tom
Jan 05, 2017, 07:44 PM
Registered User
mikeshellim's Avatar
Quote:
Originally Posted by Bmwjoon
I know RC-SOAR uses a kapow flight mode but I wouldn't do it that way. Yes it means less lines in the mixer but it would be harder to fix aforementioned issues like aileron to flap interference.
The key reason behind a dedicated 'Kapow' mode was to allow independent adjustment of elevator travel and trim. Otherwise you're stuck with the full down elevator deflection from the flight mode which happened to be active when you pulled Kapow.

Protection against flap/aileron interference is no more difficult with a dedicated flight mode. A time delay can be added to the flap line via one virtual channel and two extra mixes. Perhaps add this to 3.1 (with a default delay of zero).

Quote:
In OpenTX I would just create a logical switch for full down and add lines in the mixer for the Kapow. I suppose if I was careful I would pick the flight modes I would want to use these in, probably all he modes minus launch and zoom would add some margin of safety.
A simple mod allows you to pull Kapow from any flight mode except Zoom and Launch; remove the reference to 'L6' in the last column of L10. I'll make a note to add this in the docs.
Last edited by mikeshellim; Jan 05, 2017 at 08:08 PM.
Jan 05, 2017, 07:46 PM
Registered Taranis User
Miami Mike's Avatar
Hi Mike!

Tom, those are all points worth considering. Thanks for the input!
Latest blog entry: Taranis: Aileron-To-Rudder Mix.
Jan 05, 2017, 10:35 PM
Registered User
Mike, 3+1=4, so does 2+2

All I'm saying is I wouldn't waste a flight mode on kapow because you don't have to. Nothing wrong with how you did it.
Jan 06, 2017, 12:17 AM
I don't want to "Switch Now"
pmackenzie's Avatar
Quote:
Originally Posted by Bmwjoon
I think Mike wants a switch to "arm" the Kapow so it doesn't get activated unintentionally. Maybe he likes going full on the sticks Just kidding.

To your point though I don't think anyone ever goes full down unless landing so an "arming" switch is unnecessary.

In OpenTX I would just create a logical switch for full down and add lines in the mixer for the Kapow. I suppose if I was careful I would pick the flight modes I would want to use these in, probably all he modes minus launch and zoom would add some margin of safety.

I know RC-SOAR uses a kapow flight mode but I wouldn't do it that way. Yes it means less lines in the mixer but it would be harder to fix aforementioned issues like aileron to flap interference.
You could create a flight mode so that the priority was clear.

Then in the mixer you use that flight mode to enable the mixes, and could use any delays there to eliminate the flap interference issue. So the only extra step is to add the flight mode. The rest would be the same.
Jan 06, 2017, 04:01 AM
Registered User
mikeshellim's Avatar
Quote:
Originally Posted by Bmwjoon
Mike, 3+1=4, so does 2+2

All I'm saying is I wouldn't waste a flight mode on kapow because you don't have to. Nothing wrong with how you did it.
Well you don't have to 'waste' a flight mode for crow, but people do. Same reasoning.

Main problem is not adding a flight mode, it's that OpenTx doesn't have a simple way of altering the priorities. It's a faff each time.
Jan 11, 2017, 07:01 PM
Usedbombistan
Doug Cronkhite's Avatar
Aerodynamically wouldn't the reflex actually counteract the rotation to nose down as the airfoil creates a pitching moment in the other direction?
Jan 11, 2017, 07:19 PM
I don't want to "Switch Now"
pmackenzie's Avatar
The tail has enough authority to overcome the nose up pitching moment, but if you leave the flaps down on some models ( X3 for instance) the plane will just float along nose down, right into your shins (ask me how I know )

Popping up the flaps means that the zero lift angle changes, so nose down will now mean the model goes down.
Jan 11, 2017, 09:54 PM
Detail Freak
target's Avatar
Quote:
Originally Posted by Doug Cronkhite
Aerodynamically wouldn't the reflex actually counteract the rotation to nose down as the airfoil creates a pitching moment in the other direction?
If it was a tailless wing, yes.
If what you were asking was true, your snapflap would be setup the opposite way, wouldn't it?
;-)
Jan 12, 2017, 12:49 AM
Registered User
Avaldes's Avatar
Snap flap is designed to put the airfoil into a state that is more efficient at a given lift coefficient. Since you are asking for more lift (CL) during a turn, adding camber puts the section at a better L/D for that temporary operating condition.

In the case of Kapow, yes the change of TE position absolutely increases the nose up pitching moment of the wing. However you are substantially reducing the operating CL of the aircraft almost instantly...just like pulling up your flaps. Since you are probably holding a lot of down elevator already, this causes the plane to drop fast. Frankly you would have to experiment to find out if it actually rotates the nose down. The guys above say it does so it probably does on the X3.
Jan 12, 2017, 09:18 AM
Registered User
Tuomo's Avatar
Quote:
Originally Posted by Avaldes
Snap flap is designed to put the airfoil into a state that is more efficient at a given lift coefficient. Since you are asking for more lift (CL) during a turn, adding camber puts the section at a better L/D for that temporary operating condition.
That is the conventional wisdom. However, unless you have way overballasted, current F3J plans such as X3 are very light and hence work most of the time at very low lift coefficient. Iincreasing camber momentarily with up elevator is not so important anymore. For some pilots a very modest amount of extra camber might work, but others just end up flying too slow if they use that mix. No wonder using snap flap nowadays less popular compared to the good old days of F3X.

Quote:
Originally Posted by Avaldes
In the case of Kapow, yes the change of TE position absolutely increases the nose up pitching moment of the wing. However you are substantially reducing the operating CL of the aircraft almost instantly...just like pulling up your flaps. Since you are probably holding a lot of down elevator already, this causes the plane to drop fast. Frankly you would have to experiment to find out if it actually rotates the nose down. The guys above say it does so it probably does on the X3.
X3 does not need that much down elevator for the final dork. It is easy to land a light plane with a speed that is safe and yet well above stall speed (good control response with small movements). Additionally it is anyway a good practice to fly the last few meters of landing approach with neutral trailing edge (no flaps, as this increases stability and reduces the risk of plane flipping to one side or another.

Kapow? I have read the explanations, but still do not quite understand why... Maybe it works for those pilots who are really familiar with it, but is it a definitive improvement over simple std setting? Maybe not so.
Jan 15, 2017, 03:14 PM
Sherman Knight
Quote:
Originally Posted by Kiesling
Mike,

I think using stick switches is really how the KAPOW mix is intended to be implemented. You don't want to have to think about flipping switches - just push full down and it is activated.

Tom
In the DX18/20, use a combo mix so toggling landing mode (by pulling down the flap stick) AND when the elevator stick is pushed forward past a predetermined point, the flaps and ailerons move to a new desired position.

Or use another flight mode so only when landing mode is toggled with the flap stick AND when the elevator stick is pushed forward past a predetermined point, a new flight mode is toggled and in that mode, the new TE position is set by a camber preset.

Both programming methods work.

Sherman Knight
Last edited by duworm; Jan 15, 2017 at 05:42 PM.