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Flaps w/ Elevator

Old 02-29-2016, 09:35 PM
  #1  
grant22
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Default Flaps w/ Elevator

I have a Parkzone Sport Cub that is flying beautifully. I've started playing with the flaps and they're working well. The manual specs the 3 position flaps (0mm, 12mm, and 25mm) all with no Elevator mixed in.

I notice when I reduce or even stop the throttle and apply flaps (with delay) the plane noses up, but then settles and behaves.

The question is: should I mix in elev even tho the manual doesn't call for it?
Or just live with the nose up, then let it settle?
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Old 02-29-2016, 10:12 PM
  #2  
fhhuber
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Then nose-up is a result of airspeed. You didn't let it bleed off enough before deploying the flaps.

As you get used to the flaps you'll learn to apply them in a manner that doesn't cause the ballooning to be noticeable.

Some radios or servos can be programmed to have the flaps deploy slower instead of snapping down. That helps.

After the plane slows, the flaps will actually make the nose come down.

This effect can be useful in case the elevator gets stuck (has to be near neutral...) You can control the aircraft with throttle for a safe landing.
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Old 02-29-2016, 10:41 PM
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grant22
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Ok, thx sir, you're always a great help.

I'll start working on reducing speed first. It's hard to since I land it toward me, but I'll figure it out.

Btw, I do have them set at 1.4 seconds on my DX6.

Thx again
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Old 03-01-2016, 12:14 AM
  #4  
birdDog
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Originally Posted by grant22 View Post
Ok, thx sir, you're always a great help.

I'll start working on reducing speed first. It's hard to since I land it toward me, but I'll figure it out.

Btw, I do have them set at 1.4 seconds on my DX6.

Thx again
As you are flying, walk to the other side of the field!
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Old 03-01-2016, 02:18 AM
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solentlife
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I'm a great believer in not mixing Ele with Flaps - as fhhuber says - the flaps pitch you up at speed but not when slowed.

If you mix Ele in - then you have a factor to counter when speed decays ... for me I prefer to manually apply Ele as necessary.

Nigel
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Old 03-01-2016, 03:04 AM
  #6  
grant22
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All good advice. Thx guys.

I took it out today and with less speed came zero up pitch. And I agree, I liked manually using elev in this case. I did have a scenario today where I had to pull out of a near ground stall, and the elev mixed in hindered me pulling out.

I read your responses while out there, eliminated the elev mix and all was better. Thx again.
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Old 03-01-2016, 05:14 AM
  #7  
fhhuber
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I have one model that I programmed the flaps to 5 seconds for full travel. What delay works best for you will vary with the aircraft and your flying proficiency. You may want to change the setting as you gain skill. There's also a lot of personal preference involved.


Missed approach with flaps is pretty much the same for models and full scale.

Initially, DO NOT touch the flaps.
Add power. The nose will rise.
Use elevator to control the pitch attitude.
Once airspeed starts to build SLOWLY pull the flaps.
If you pull the flaps too early the plane will crash.

Models will respond to throttle faster, because we generally have much higher power:weight than full scale. It may be better to NOT apply full throttle.

Practice with plenty of altitude...
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Old 03-01-2016, 07:53 AM
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JetPlaneFlyer
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Personally I usually mix elevator with flaps, it varies plane to plane but I find almost all benefit from some down elevator with flaps to avoid having to hold down stick all the time. Sure, if you deploy flaps at too high speed you will still balloon but I find that without some mix you often have to hold down elevator at any airspeed, which just isn't good IMHO.

I just look at it as trimming the plane for flying with flaps deployed. After all we wouldn't tolerate having to hold in constant elevator when the flaps were up, so I don't see why we accept it for flying with flaps deployed?

On the other hand if your cub does 'settle' and flies without requiring any elevator input then that's fine, you don't need any mix. But such planes are quite rare in my experience, most need some down elevator to stop them stalling with flaps deployed.
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Old 03-11-2016, 11:03 PM
  #9  
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Apropos for me, I just got this plane and am adding flaps, was wondering if the el mix was useful.

Dave
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Old 03-11-2016, 11:25 PM
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grant22
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I've tried both methods, and what's working for me is some elev mixed in

I'm bringing my airspeed down, then with half flaps, I use 20% down elev. with full flaps, 30% down elev.

I'm also using 1.4 seconds delay. On a calm to mildly windy day, this is really helping me a lot.
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Old 03-13-2016, 01:44 AM
  #11  
CNY_Dave
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Maidened today, with flaps, yeah any airspeed at all and that nose goes straight up!

I think for me flies fine with flaps and no el mix, stays level as long as the airspeed is low.
It just seems that airspeed is too low though, last planes I flew were 60 sized 5 pounders, not used to going this slow!

I don't have room for a long approach, just slow down on the downwind leg (can you really slow to a speed without flaps where it won't balloon?), pop flaps, dead stick, descend on an all-curving crosswind leg, line up and keep the nose down until low, level, let the speed bleed off, and it's down!

Now, why the heck don't we have airspeed sensors yet, we could mix in down elevator with flaps based on speed.
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Old 03-13-2016, 03:00 AM
  #12  
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We do have the airspeed sensors...

And higher capability autopilots that could apply elevator to maintain attitude.

None that connect the two, but the connection is not needed to prevent ballooning. Just to detect stall and allow the nose to drop.
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Old 03-13-2016, 03:08 AM
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If you really want to land on a dime and have a short glide in ... use SPOILERS .. but only a small amount such as SPOILERONS.

I have an Edge 540 racer ... she just goes a mile if you let her glide in like most other models. Some people create flaperons and say it works ... but having tried it and many others say same - it is not so good ... in fact it slows the speed envelope but you are still landing in next field !!
Create spoilerons though and bingo ... glide slope angle increases, you can keep speed up ... land far shorter ...

All it needs is a few mm up and you have it.

To make flaps really effective for landing ... you need a lot of movement and then power to compensate the drag. Elevator to hold the pitch angle. Next time when flying on a commercial study the approach and when he starts deploying flaps and later increasing them. Makes our elevator - flaps discussion pale !!


Nigel
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