flyin' kingsfk

How to Program Airbrakes for the Delta Vortex - An Overview

by Bruce Tharpe

I've had some questions about how to program the airbrakes on the DV. By airbrakes, I mean the rudders both deflect outward with the flip of a switch, thereby creating drag to slow the model quickly during a landing approach. They work great on the DV! It takes a pretty high-end radio with plenty of mixing capability. Personally, I set mine up with an old Ace Micropro 8000, which very few people use. Point is, I can't give specific instructions for specific radios that I don't use. However, the concept is universal and with some "figgerin" and head scratching, I'm sure most builders can do the actual programming. Stick with me now...

For rudders, airbrakes, and nose wheel steering, you need three servos - one on each rudder and one for the nose wheel. Each servo must be plugged into a separate receptacle on the receiver.

To make this all work, you must program four different custom "mixes". Each mix involves two channels; one will be the master and one will be the slave. The four mixes are as follows:

MIX 1. Rudder Servo #1 (master) -> Rudder Servo #2 (slave) This simply makes the rudder servos work together as rudders. They should move in the same direction, using the rudder stick on the transmitter.

MIX 2. Rudder Servo #1 (master) -> Nose Wheel Steering Servo (slave) This is to control the nose wheel servo with the rudder stick on the transmitter, as usual.

MIX 3.
Airbrake Channel (master) -> Rudder Servo #1 (slave) You can choose which channel you wish to use for airbrakes. The easiest is probably the retract switch, but you may prefer a flap knob or some other switch on the transmitter that is not being used.

MIX 4.
Airbrake Channel (master) -> Rudder Servo #2 (slave) Same as above. The rudders should both deflect outward when the airbrake channel (retract switch) is activated. You should still have some rudder control when the airbrakes are deflected.

Programming the Futaba 7CAP

Submitted by BTE Customer Barry Whiffin

Hi Bruce, Thanks again for a great kit. The split rudder airbrakes gave me some serious trouble using a Futaba 7CAP transmitter. This is due to it only providing 3 Mixers and not the 4 Mixers you give in your website example. This is a popular transmitter and I thought this solution might be of use to you and your customers. It also provides the added benefit of being able to mix elevator in with the airbrakes without any additional hardware mixers.

My solution for the Futaba 7CAP is to use the following:

Channel 1 = Left Elevon
Channel 2 = Right Elevon
Channel 3 = Throttle
Channel 4 = Rudder 1
Channel 5 = Nose Wheel    In param menu set Chan5 to -- (no switch)
Channel 6 = Rudder 2

FLAPTRIM = ON 0% 0% (This stops the Chan6 knob operating only Rudder2)

PMIX1   4>5   SW --    (Rudder1 to Nose Wheel and always ON)
PMIX2   4>6   SW --    (Rudder1 to Rudder2 and always ON)
PMIX3   OFS>4   SW G    (Allows Rudder1 to be offset using the airbrake switch G)

So when I throw SW G and activate the Airbrakes (Rudder2 on Chan6) the same switch G also activates PMIX3 Rudder1 with an offset. The result is both rudders move on the same switch G. The bonus is that due to using the Airbrake function I can also go to A.BRAKE settings and dial in an elevator correction should one be needed during airbrake deployment.

Only problems I can see are
1. that the trim lever on Rudder1 only moves Rudder1 on Channel 4, not Rudder 2.
2. the amount of Airbrake on the Rudders has to be adjusted in two places (A.BRAKE and PMIX3).

Programming the Futaba 9C

Stumbled upon by Bruce Tharpe offers detailed instructions in their FAQ section, just click the link below. If you are a 9C user (like me), you will find a wealth of info there that will help you get the most out of your transmitter.

LINK How do I set up the 9C for a delta wing with dual rudders? Can I use the dual rudders as airbrakes?

Programming the Futaba 8U

Submitted by BTE Customer

"Bruce, Using the '8U' Futaba transmitter, here is one way to make both rudders work together and also to be able to throw a switch to make them act as airbrakes and to allow the nose wheel to turn:



#1 MIX = Makes the nosewheel move with the right rudder.
#2 MIX = Makes the left rudder work with the right rudder.
#3 MIX = Using this switch activates the right rudder to be an airbrake.
#4 MIX = Using this switch activates the left rudder to be an airbrake.

Hope this makes sense to you. It works for me.........Tony"

Programming the JR 8103

Submitted by BTE Customer Scott Orten

"The kit was great. I have been building kits since the early 80's and found that your instructions were great and your building tips told me things I had not known or done before.

"I had a big problem finding someone to help me program my JR 8103. After several calls to the people who did the magazine articles and several calls to JR, I finally got a call back from JR.

"Thanks again for a great model."

Elev - Adjust for rudder compensation
Flap - D170
Spoi - INH
Auto - INH

Flap Pot

Mix 3 Aux3-Aux3
Rate -100, -100
SW on

Mix 4 Rudd-Aux3
Rate +100, +100
SW on

Mix 5 Flap-Rudd
Rate -100, -100
SW Land

Mix 6 Rudd-Flap
Rate +100, +100
SW on

Travel Adjust
Aux3 +100, -100
Flap +100, +100

Rudd = Left Rudder
Aux1 = Right Rudder
Aux3 = Nose Wheel Steering

Programming the Spectrum DX7

Submitted by BTE Customer Lloyd Roberts

AILE = Left Elevon
ELEV = Right Elevon
RUDD = Throttle
AUX1 = Left Rudder
AUX2 = Steering


MIX 1 Activates Nose Wheel Steering
RATE +100%

MIX 2 Activates Rudders to Work Together
RATE +100%
OFFSET: Adjust for Equal Travel

MIX 3 Activates Air Brakes Using GEAR Switch on Transmitter
RATE -125%

Bruce's Comment: Buyer beware! I have modified Lloyd's original instructions slightly, because he needed to use the GEAR switch for the retractable gear on his DV. Instead, he used the FLAP MIX switch on the transmitter, which is a three-position switch and introduces a serious problem. Flipping the FLAP MIX switch the wrong direction would deploy only one rudder, a mistake you would not want to make on short final. So I strongly suggest you use the GEAR switch, although the programming shown above is not proven and may require tweaking.

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