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scale flap operation

Old 06-26-2003, 03:15 PM
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Default scale flap operation

Flaps are operated from the TX usually via a flap knob potentiometer (as well as a toggle switch). But most flap operation is not continuous but in set steps.

For example, the angular deployment of flaps may be:

Cruise: 0 deg
Climb: 10 deg
Takeoff: 35 deg
Landing: 50 deg
Full: 60 deg

I wonder if one could not substitute 5-position micro rotary switch with hard-wired resistance values for the flap pot to get these discrete steps.

Either that, or keep the stock flap pot and fabricate a 5-step detent assembly as an add-on.

It's not impossible to "dial in" the flaps by feel, but I've toyed with the idea of this stepped deployment and thought I'd run it by the collective consciousness here...

--Bill
Old 06-26-2003, 05:17 PM
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Default scale flap operation

One interesting way to implement that would be to incorporate a small circular racheting indexer. Each time you cycled through the flaps switch (throw it in the opposite position and then back again), a rod connected to the servo would pull back and then push forward and engage the indexer. Each time the indexer would index a portion of a revolution. For half the circle, the flaps would be moving lower and for the other half, they would be raising.

The mechanism should not be to complicated but I do see a few problems. There is no way for the flaps position to be indicated on the transmitter. You would either have to see them on a fly-by or remember how many times you cycled the flaps switch.

The other problem is that there is really only one way to go through the cycle. You would have to go from no flaps through full flaps and back again. Also remember, each flap position would be available on both halfs of the circle (going down and coming up) so for before take-off, you could cycle through full flaps and leave it at 35. Once airborne, the next click would be 15, the next one would be no flaps. What you couldn't do is set your flaps at 50 for landing pull them back up again without going through the full flaps setting.

It is reasonably simple but there are a few issues.
Old 06-26-2003, 06:30 PM
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Default Flaps

Bill, if you have a 9z futaba or the 10x jr you can do what you wish by assigning conditions with seperate flap settings for each condition.. but.. on a model.. flaps of several settings is not necessary.. typically you have 0-40-60 and full.. that gets you what you need in almost any situation. Many models dont even need flaps but the full size would.. just something to consider.. BobH.
Old 06-27-2003, 06:38 AM
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Default scale flap operation

Bill
There is a new transmitter out on the european market (JR/Graupner mx22). It has two switches whitch can act as steppers (the way you want it), they just aplly incremental an decremental steps on a function. However, that's the expensive way (1000$) .
If you want a microswitch setup like the one you mentioned, I could figure out a schematic for you. It shouldn't be too difficult.

Flo
Old 06-27-2003, 11:58 AM
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Default scale flap operation

The futaba 6 channel transmitters like the Skysport6 and the 6XAS only have the rotary dial as Bill describes. I am sure that you could "hard wire" a multi position swith in place of the factory near useless dial.

Only problem I see is sourcing a small switch with that many positions.

Ben in SC
Old 06-27-2003, 12:29 PM
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Default scale flap operation

Couldn't you program a mix using the three position switch?
Old 06-27-2003, 12:30 PM
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Default scale flap operation

I hate that stupid rotary dial for flaps on a lot of radios. I ended up epoxying on a small plywood lever on the dials. Then I can feel what position the lever is in or take a quick look at it and see how far over it is. It's still kind of awkward to use.

I liked the older Futabas that had a slider type controller for the flap channel. I only have one of those.
Old 06-27-2003, 12:44 PM
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Default scale flap operation

There may not be need for several steps for the flap operation, but it makes for more "scale" actuation to have the 4-5 settings. A minor nit, but that's the way we scale-types are.

The mini rotary switch source isn't a problem: Digikey http://www.digikey.com/ or Mouser http://www.mouser.com/ stock components of that sort.

Actually, the more I think about it, adding a 4-6 step detent or indexing assembly to the stock flap pot would work best.

The flap pot is/was 10K and acts a voltage divider that applies a voltage to the appropriate input to the encoder chip, so the electronics of this conversion isn't difficult.

Yes, Graupner/EuroJR, Multiples, etc, have some NICE user-customizable features to their "pizza box" Tx's.

--Bill
Old 06-27-2003, 06:26 PM
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Default scale flap operation

Ace use to make a product called SERVO MASTER and I use on my Seniorita for the flaps. The signal from the reciever is plugged into the SERVO MASTER and the servo for the flap is plugged into the SERVO MASTER.

when you hit the toggle switch on the transmitter the flaps do not snap down, they move slowly to it's new position (5 -10 seconds), this allows you to feed into down trim on the elevator to counter act the nose up trim due to the flaps.

If the flap deploys very quickly this noseup trim change is more noticeable.

Unfortately ACE no longer makes this product but worth mentioning if you know someone who can make one or if you find one on the used market.
Old 06-27-2003, 06:57 PM
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Default scale flap operation

You guys are kidding right? That "useless" dail on your transmitter works the way most civil aircraft work. My fullscale Mooney M20-J has a momentary down/switched up switch for the flaps. Hold the toggle switch down for 3 seconds and you get TO position or about 15 degrees in the pattern. Their is a little tiny indicator if you want to take your eyes off the windshield to look down near the floor to see it. Hold it down until the indicator hits bottom for full flaps. Some Cessna's are the same way and some have detents. Flaps don't have to be exact.

Put a white sticky dot on your knob with a large pointer on it. Put a white sticky (tape) on the transmitter next to the useless knob and mark off the flap settings you want. 0, 1/3, 2/3 and full are all you need. Some times just 0, 1/2 and full are all you need. You can always check it with a quick glance. If you miss by 3.5 degrees your aircraft will not complain. Bringing the flaps to zero for a go-around just means turning it all the way to the left stops. Is there something here that makes this too hard to do while flying? You could always assign the flaps to the 3 position switch. I have done this before. 0, 1/2 and full flaps. A model does not really need any more than this. Just make sure that the 1/2 setting is no more than 20 degrees. Zero to 20 degrees adds more lift than drag on most airfoils. Beyond 20 degrees you are adding more drag than lift. Use both settings accordingly, one for adding lift and lowering stall speed and one for adding lift and slowing the plane down dramatically.
Old 06-27-2003, 07:04 PM
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Default scale flap operation

35 degrees flaps for take off that's a lot !!!
Old 06-27-2003, 07:39 PM
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Default scale flap operation

Those values are for the deHavilland Beaver:
Extracted from USArmy TM55-1510-203-20
Reference point Inbooard Wing flap hinge
Settings for proper rigging.

Cruise 0
Climb -15 +/- 1
Takeoff -35 +/- 1
Landing -50 +/- 2
Full Flap -58 +/-
clscale: that device is called a "goslow" (Go Slow) and can be bought from McDaniel RC, based on a design by Brent Dane: http://www.cliftech.com/ . I'm using on on the flaps on my Flyin'King.

chopp3r: yes, much like the flap control on a full scale. But riding in, as opposed to flying via remote, you get analog feedback as you fly. With RC, you have to rely on remote clues.

On my rotary flap knobs, I've added a protrusion to the side of the knob so that I can have a tactile sense of the knob position: 0, 1/4, 1/2, 3/4 or 4/4, which is good enough and not hard to use. Or assign flaps to the 3-position switch. Not an impossible situation, but one that could be improved.

Good discussion!

--Bill

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