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        How to have Flaperons (flaps + ailerons) with a 4 channel receiver

#1 Flying Cat Jun 12, 2002 02:54 PM

How to have Flaperons (flaps + ailerons) with a 4 channel receiver
 
The field where I fly my pylon racer is not too big, so I decided to install two servos on the wing to have FLAPS and/or AIRBRAKES so my plane can land shorter distances. The challange was that I wanted to continue to use my light GWS R4P receiver that has only 4 channels, without having to go to a heavier 6 or 8 channel receiver.

Since Ch4, the rudder, of the receiver was not being used,
I connected the right aileron to Ch1 of the receiver, and the left aileron to the unused Ch4. By using the programmable mixers in my Futaba radio my plane now has flaperons using a 4 channel receiver!

These are the mixers I am using:

PMIX1
Purpose: Send transmitter signal from aileron stick to Ch4 of receiver.
Settings: Master: AIL; Slave: RUDDER; 100%, 100%; Trim: ON; Link: ON, Offset: 0%; Switch: A-Null (= feature always on)

PMIX2
Purpose: Inhibit Rudder stick from sending signal to Ch4 of receiver; i.e., disable Rudder stick on Transmitter.
Settings: Master: RUD; Slave: Rud; -100%, -100%, Trim: ON; Link: Off; Offset: 0%; Switch: A-Null (= always on)

PMIX3
Purpose: Move right flaperon up when throttle stick is 7% up; i.e, when I am about to land and I am cutting off the power.
Settings: Master: OFS; Slave: AIL; 45%, Switch: Stick3 at 7% with little triangle under the number 3.

PMIX4
Purpose: Move left flaperon up when throttle stick is 7% up.
Settings: Master: OFS; Slave: RUD; 45%, Switch: Stick3 at 7% with little triangle under the number 3.

PMIX5
Purpose: Trim elevator as flaps move up.
Settings: Master: OFS; Slave: ELEV; +5%; Link-Off; Switch: Stick3 at 7%.

I first tried controling the flaps by using the transmitter knob for Ch6, but it is hard to set to neutral while flying. Next, I had the Airbrake Switch on my radio control the flaps; i did not like this setting either because I needed to flip the switch when the plane is just about to land. Now I have it set up so the flaps go up automatically when I am cutting the power. I really like this setting because I can concetrate on landing.

My next step will be to use the spare mixers so the flaps move in the opposite direction of the elevator to have tigther loops.

Please note that the sign of the percentages in all the programmable mixers are dependent on your specific servo installation.

Let me know if this information is useful to you. And I am also interested in learning how you are using the mixers in your computer radio to "enhance" the performance of your plane.

Regards,

Flying Cat

#2 KillerWatt Jun 17, 2002 12:47 AM

hi Flycat.....neat set-up.....i might need to use this scheme soon....about your 2 wing servos and the gws 4 ch (pico)receiver......are you aware that by adding 3 simple wires to the receiver's ckt board, an additional 5 th is available, also another for at least 6 operational, seperate chan functions for standard or micro servo's ???? assuming you have a 5 or more chan tx. that would give you full, standard ailerons + flaps chan control without mixing ....just thought i would mention this if you didn't already know................kw

#3 Tuomas Pietinen Jun 17, 2002 02:05 AM

GWS..
 
Sounds fine to me exept I would never put a GWS receiver into a pylon plane....I fly my Stingers with Multiplex Pico and Avionik with Hitec 555 Dual receivers and with very little problems. I highly recommend the new Schulze receiver!

#4 Petri Nygren Jun 17, 2002 02:19 AM

Nice setup. What I use is MPX4000 programmed so that I get elevator up -> flap down mix from behind a switch and three flaperon settings from another switch, for takeoff, flight and landing.
I have finally got everything dialled to my liking but have started doubting whether it is worth the trouble really. Turns are better now but watch out. Nearly all of the aileron authority is lost with flaps plus that increased profile moment tries to stall the elevator in flare.

What I am concerned in your setup is your receiver. I wonder if you have flown with it yet. You may or may not do fine with it while flying alone but the first flight you do with your buddies may be the last, I am sorry to say. Iīve seen micro Rx pylon setups chrash and would thus vote for 6-8 channel mini Rx for LESS trouble.

Petri

#5 Flying Cat Jun 17, 2002 08:14 AM

KillerWatt,
Thank you for the information. I suspected that the chip GWS is using is decoding more channels than the 4 they offer. It would be great if you could tell me what chip & pin numbers are the ones I need to tap in the receiver to have access to Ch.5 and Ch.6 in the GWS R4P receiver.

Petri,
You are right about the risks of using a single conversion receiver. However, I always fly by myself, so I do not have interference problem. I have an FMA Fortress, dual conversion receiver that I can put on my pylon racer if I go flying with others in the future. FMA receivers have outstanding performance, and have a very good reputation. The Fortress receiver I have weights 15 grams, and FMA has recently come up with a lighter dual conversion receiver that weights only 10 grams!

Flying Cat

#6 KillerWatt Jun 20, 2002 09:44 PM

hey flycat......i can't seem to find the printed info i have on adding extra chans to the R4P receiver ...i'll keep looking thru my stuff, you might try doing a search thru the various e-zone groups like this one or park flyers, but i'm sure i can find it this weekend......kw

#7 TedLarson Jun 30, 2002 11:24 PM

Flying Cat,

What make and model of transmitter are you using?
If you are using a programmable Futaba like a 6AX, you can use the programmable mixer like you mention, program the mix to channel 6, which is the knob, and set the ATV of the channel wayy back on only one side. Then there is no neutral setting issues. You turn the knob all the way in one direction, or all the way in the other....never in the middle.

Next, I don't recommend using flaperons. The effect flaperons have on flight is usually disasterous. When you drop both your ailerons, on a plane, you are essentially inducing a negative washout in both wings, which will make your plane VERY sensitive to tip stalling the slower you go. I have seen at least 3 separate people start flying with flaperons, and crash while landing due to a tip stall. Also, you are wanting to land in a shorter distance. Flaperons will make the plane more floaty, and more prone to ground effect also....again...also increasing your chance of a tip stall.

If you can setup Airbrakes, then this is the way to go to solve your short landing problem. You will need to mix in alot of up elevator in order to level your flight when you kick them on. It will have a tendancy to pitch the nose down sharply when you pop your ailerons up. Futaba has an Airbrake switch you can program, so you can just kick them on with a switch. I have had bad experiences with the Airbrake feature as well. It has a tendancy to spoil all the airflow over the wing and cause you to flop to the ground like a pancake. I only recommend kicking them on, right before touchdown, during ground effect, or you are likely to stall easily on approach.

Also...not to seem lecturous or anything...but, I totally agree with Tuomas on the GWS single conversion receivers. All it will take is for you to completely destroy your plane, from a radio glitch, and the $30 you saved, suddenly doesn't seem worth it anymore.

Hope this helps,

- Ted

#8 Petri Nygren Jul 01, 2002 02:29 AM

Not quite so
 
Quote:

Originally posted by TedLarson

Next, I don't recommend using flaperons. The effect flaperons have on flight is usually disasterous. When you drop both your ailerons, on a plane, you are essentially inducing a negative washout in both wings, which will make your plane VERY sensitive to tip stalling the slower you go. I have seen at least 3 separate people start flying with flaperons, and crash while landing due to a tip stall. Also, you are wanting to land in a shorter distance. Flaperons will make the plane more floaty, and more prone to ground effect also....again...also increasing your chance of a tip stall.

If you can setup Airbrakes, then this is the way to go to solve your short landing problem.
- Ted



Ted,

Most E-pylon racers I know of have ailerons that start from the wingroot and end some distance from the tip. Thatīs how it is in my Stinger and also in Flying Catīs Python. When you use flaperons in such layout, you generally donīt have to fear tipstall. I bet all the flaperon crashes you saw happened to models with wingtip ailerons. When you have aileron in the tip and drop them both down, you effectively create wash-in in your wing and get immediate tipstall danger.

In Stinger, aileron chord is increasing towards the wingroot and that coupled with the fact that aileron does not extend all the way to the tip, actually increases the wash-out when flaperons are lowered.

Moreover, when you use full span - variable chord - non wingtip reaching aileron as an airbrake by taking them up, you actually create highly undesireable wash-in to your wing! Dont do it -its a quick way to disaster! Its meant only for wingtip ailerons like found in most gliders.

I would also prefer having a good stall AoA (high Clmax) in landing, and thats actually made worse by full span airbrake setup. In other words, when you take the ailerons up, your wing stalls earlier. Not nice at all.


Petri

#9 TedLarson Jul 03, 2002 12:42 AM

I stand corrected then. Most of my experiences have been with planes that either have the entire trailing edge of the wing being an aileron, or where the ailerons are on the tips of the wings. Most of the planes I have seen crash, are glow conversions to e-flight, where the wing loading is really high, and where they are looking for a way to slow down more before landing.

Most of my airbrake experiences have been on hotliner-type planes, where landing them is a real chore, because they just don't want to come down.

Anyway, I never knew that about non-wingtip reaching ailerons. I'll have to keep that in mind if I ever own a plane that has them.

- Ted


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