Easy way to adjust Flap/Elevator mix IN FLIGHT using mixing

[andrew_flyguy]

Dialing in elevator/flap compensation has been an issue I've had to deal with since I started flying 5+ channel RC planes... and I'll bet I'm not the only one!

If you've got a RC computer transmitter, 2 free mixes, and some available input for the mix (unassigned trim switches, sliders, rollers, knobs, etc.), odds are this will work for you.
I really hope this saves folks some time and stressful flying!

https://youtu.be/HN4G9CGOOc4

[OV10]

Well that was just down right :Cool: Can't believe nobody ( including myself) hasn't been ingenious enough to do this before Andrew :Smug:LOL Thanx for the great tip man :)

[MOFO1]

flyguy what a great tip. Tried it on a airplane and it worked great. Didn't have to do all the landing and adjusting routine.Saved a lot of trial and error time. Thanks again.

[E-Challenged]

I'll see if I can set up the same mixes with my Aurora 9. I have noticed that amount of down-elevator compensation needed, if any, changes with headwind and airspeed. My high winged Tritle balsa Stinson Reliant tends to balloon nose-up while my foamie ParkZone Stinson Reliant drops it's nose with full/landing flap, go figure!

[fhhuber]

I've been using the Spekrum "Flight Mode" feature.

Test flight, common trims. This is so you won't have to do any major trim adjust that is common in all modes more than once.
Then set to trim by flight mode.
Now you just apply flaps, trim it and.. done.

Note that the DX-18 has 5 flight modes, but you only get 3 different trim settings. Select which flight modes are applied to which trim setting (its which switch is in position 0 vs not in position 0... and you use 2 switches to get the 5 flight modes)
Its easy to set so that the flap positions needing elevator trim get the different trims.

[Aros]

That's a great tip! Never thought about that before...I bet this would be a great article for the Knowledge Blog. Mind if I create an article for our KB and credit you and of course the YT video/author?

[andrew_flyguy]

That's a great tip! Never thought about that before...I bet this would be a great article for the Knowledge Blog. Mind if I create an article for our KB and credit you and of course the YT video/author?

I'd be honored! Glad it's proving useful for others :Cool:Let's keep it going!

[Aros]

You're name is in lights! Okay, maybe not lights. But you made a Knowledge Blog article. ;)

Thanks again!

https://www.motionrc.com/blogs/motion-rc-blog/how-to-adjust-your-flap-elevator-mix-in-flight

[andrew_flyguy]

Awesome! Thanks a ton, Aros!

[Aros]

Thank you!

[Tom]

brilliant! Thanks for posting this.

[Hugh Wiedman]

Dialing in elevator/flap compensation has been an issue I've had to deal with since I started flying 5+ channel RC planes... and I'll bet I'm not the only one!

If you've got a RC computer transmitter, 2 free mixes, and some available input for the mix (unassigned trim switches, sliders, rollers, knobs, etc.), odds are this will work for you.
I really hope this saves folks some time and stressful flying!

https://youtu.be/HN4G9CGOOc4

Hey Andrew, nice fix, but I have another way to do it that I think is easier, quicker and offers more flexibility (maybe only because I have used this method for a couple years).

Franco Di Mauro, the big jet guru of House of Power, showed me this (we are lucky to have him at our field most days and is always willing to give a hand to anyone). A couple years ago, I had 1 of my new planes (can't even remember which one) at the field to maiden and he was there with 1 of his new $15,000 jets testing for a client and he mentioned to me that he wanted to see this model fly and let him know when I take it up. I promptly handed him my transmitter and said why don't you maiden it for me and set up all my trims so I have one less thing to deal with when I fly it. He checked out all the surfaces and then asked me how I trim with the flaps deployed, and I said "on the ground with the flap setup menu". He said oh NO, and then started speaking Spanish at 100mph and his fingers moved on my transmitter like he was do a harrier roll in light speed. 10 seconds later I said what the hell did you do? Here's what he did:

Go to System setup on your transmitter (2nd menu on a Spektrum) then scroll down to Trim Setup (so far, pretty logical)
Next to Throttle, keep the Trim Type at Common Digital, but next to each the Aileron, Elevator and Rudder change the type to F Mode (this assumes you have gone to the F Mode Setup, and set the Flight Mode Switch to the flap switch, which in my case is Switch D-this also happens to be my stabilization switch for my gyro-giving different gains on each flap position)
That's it, you're done. The result is, you can now trim each surface using your regular trim switches just like you have been doing for years but it is individualized at each flap setting. And if you like to use cross trim levers, change it at the bottom from Normal to Cross.

I love this as I have different trims at each flap setting that can be changed in the air while flying just like you trim normally. You don't have to search around for a separate knob and remember which is for up and which is down. This gives the added flexibility of being able to trim Ailerons for each flap setting as well (haven't yet had to adjust the trim on the Rudder), in case one flap deploys at slightly a different distance that could cause a slight roll, which would get worse at full flaps. Additionally this works on the DX6 through 12, as you are not using any "new" buttons, just your standard trim levers (I suspect most manufacturers transmitters must have a trim Setup function).

For me, this is very easy to use, as I first trim all my surfaces on the maiden for each of the 3 flight conditions (flaps up, take-off flaps & Landing flaps) and it's solid as a rock when changing flaps. If I increase the flap deflections, it's a simple trim exercise for all 3 surfaces if needed that we do all the time.

Your fix works well, but I've gotten so used to the this way that I'm sticking with it. And if Franco uses it on a $15,000 jet, who am I to argue. :Silly:

[andrew_flyguy]

That's a good method as well, Hugh. I hadn't thought to use Flight Modes that way. I've only used Flight Modes to allow different trims for wings out or wings swept on my Tomcat. Trimming a plane out 3 times doesn't sound too fun to me, but hey - I'm all about knowledge and options, so thanks!! :Cool: I think Fhhumber had posted a similar solution above.

[Hugh Wiedman]

That's a good method as well, Hugh. I hadn't thought to use Flight Modes that way. I've only used Flight Modes to allow different trims for wings out or wings swept on my Tomcat. Trimming a plane out 3 times doesn't sound too fun to me, but hey - I'm all about knowledge and options, so thanks!! :Cool: I think Fhhumber had posted a similar solution above.

Sorry, Andrew, you are 100% correct, Fhhumber did suggest that, I must have missed it. For those of you that really want to get "too sexy for your shirt", set at the bottom of the Trim Setup screen the trims from normal to Cross. A very experienced pilot suggested this to me as well, allowing you to adjust the trim of the elevator and aileron using the left trim levers while still keeping your right hand on the right stick to correct elevator and aileron so you don't get into a really bad orientation if your trim is off significantly. The rudder and throttle are now on the right. I haven't done this, as I'm so used to trimming the levers in the default positions that I'm afraid I'd get confused and trim the wrong surface-got enough to think about just keeping it flying. I suppose if I was just starting, or experienced enough to keep my wits about me, I would cross them, as this really sounds like a good idea.

BTW, for those not aware, I forgot to show the screen on Flight modes, which is attached. Set the switch to whatever your 3 position flap switch is to activate (I use Switch D) if you want to allowing the trims levers to work separately on each flap position.

Having to do all surfaces with each flap position isn't all that bad. I usually only have to do it on the maiden and invariably need to also adjust the ailerons 1 to 2 clicks. Never had to change the rudder, so really it's just the 2 surfaces.

[Hugh Wiedman]

BTW, if you don't want or need to trim all three surfaces which each flap setting, then just change the elevator line to F-Mode, and none of the others (or just the elevator and Aileron if you like). This way, you only need to trim 1 surface (the elevator) in each flap position. The reason I like this method is that your trim adjustment is always using the same lever, no matter what plane you fly and if you are using a DX6, you don't have to upgrade to get more functional knobs. At the end of the day, whichever method you feel most comfortable is the best. At least with either method, you can adjust in flight to the exact correct trim you need without landing and trying to guess how much trim in required.

Great topic Andrew.

[andrew_flyguy]

change the elevator line to F-Mode, and none of the others (or just the elevator and Aileron if you like). This way, you only need to trim 1 surface (the elevator) in each flap position.

Great topic Andrew.

I like that version of the flight mode solution even better. Thanks for the learn, Hugh! :)