Don Szczur

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I was asked to put together some thoughts and quick hints for setting up a plane on the DX 18. Actually, I was asked to do this for a club program, so here are some notes I'm putting together real time.

Don Szczur

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Tonight the first item is related to Flight Modes. I got several questions from folks that are new to Spektrum (or JR for that matter) and are not used to the terminology, “flight mode”. Basically think of Flight Modes as dual rates with lots of options. In fact you can program up to 5 flight modes (10 for sailplanes to be assigned to any switch or combination of switches, using up to four switches). For pattern flying I normally have three flight modes (one for regular flying, one for snaps, and one for spins) or five flight modes for IMAC using two switches (first three same as pattern but an extra one rolling circles, and one for 3D). I also did try a couple of 3D flight modes in the past- one for rolling harriers which like a little less aileron to keep up with the rolling harrier rate, and one for the rest of 3D high alpha maneuvers).

So, this may get complicated very quickly, but gives a tremendous amount of capability. Let me give you a couple of simple examples. One is spin entry. If your plane, for whatever reason, breaks one direction in a spin. Let’s say you are coming up to a spin entry and it wants to break off to the left every time. Now, understand that first you should already have the airplane trimmed as best as possible with thrust, incidence, wing balance, etc. (That is a topic for another thread). Now after trimmed properly, let’s say it still wants to break to the left by itself every time you come up to a spin entry. You want to have a flight mode trim set up for spin rates, which puts a little bit of right rudder when you approach the spin and hit the switch (just like you would if you hit the dual rate switch). By the way, I had an IMAC plane that broke straight ahead from upright spin, but from inverted it needed a different rudder trim to break straight ahead in a spin entry and not have the nose wander off one direction as I was approaching stall.

First, go to flight mode setup in the system menu. Select F Mode Setup, and select the switch you want to set up the flight mode (I use switch F) then you are done! You then go to “Trim Setup” in the system menu and select “flight mode” for each trim you want affected (in my example, rudder). You are done! If you want to name your flight mode (e.g., regular flight, snap, spin) go back to system menu, select “Flight Mode Name Setup”. Then name each one as appropriate.

Now, you want to do this all AFTER you have the plane all set up and trimmed out. That way the F Mode trim will carry your baseline trim for all the flight modes, and then you can do the fine tune trim for the spin flight mode (as you approach your stall for spin you can adjust the rudder trim to get a nice clean straight ahead break on your spin, and not affect your regular flying trim). You also want to make sure you take note of this if you transfer models to a buddy who wants to start with your model memory as a baseline for his plane (and who may not need this flight mode trim setup for his spin entry).

Another example is a landing Flight Mode, which neutralizes the throttle-to-down elevator mix (you may have in for your straight vertical down lines for square loops and stall turn downlines).

Will get into otehr setups a bit more deeply next time. Good night.

Don Szczur

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This evening I’ll talk more about flight modes. Here is another example. While flying electric, I noticed that some of the larger pitch propellers that are very light have the tendency to slow down quickly when entering a stall turn. This reduces the air blowing over the rudder during a stall turn itself. By setting up a flight condition for stall turns, you can put a bit more idle trim (idle up) for getting a smoother stall turn. You can even set up a completely separate throttle curve for each flight mode. This not only gives you the ability to idle up during a stall turn, but provide a different power curve for some maneuvers- for example snap rolls on a 45 degree down line may require more mid- stick throttle curve to get it cleanly executed. By tying a throttle curve to your snap rate (flight mode) it gives you more power where you need it during that snap maneuver.

Don Szczur

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With respect to idle down for landing, the same can be done using flight mode trim. I normally land with very low idle (just enough to keep the motor spinning in order to slow the plane down). I also land on high rates (spin rate) for extra control. One way to set up a flight mode so that the idle is set lower to slow down for landing. Finally, as discussed earlier about some elevator trim (up elevator trim) that comes in at low throttle- just a little which basically would offset the down throttle to down elevator (you should make sure that you disable trim on that P Mix- a subject for another evening) that is used for straight down lines during square loops or other maneuvers that have a down-line. However, I actually fount that it’s easier to just turn that mix on and off from the P Mix menu directly (linking it to flight modes or tie it to your dual rate switch rather than leaving it on all the time rather than setting up a separate flight mode trim for idle to change with position of the throttle stick.) See pictures.

So as you can see there are a whole lot of opportunities for flight modes in your programming setups

Don Szczur

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Some other helpful setups from my Black Magic powered by a YS 175 engine.

- Aircraft type- this is a simple user graphic that guides you to setting up dual ailerons and dual elevators. This is from the system menu.

- Rx port assignments. Basically you assign whatever you want to each port. This is my setup for my rx. Again from the system menu.

Don Szczur

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For the Black Magic, setting up dual ailerons and dual elevators

Don Szczur

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- Trim setup. I have this set up simply right now, with standard trim setup. From the system menu.


- Warnings. I have the throttle warning for 10 percent throttle so I don’t start the motor with the engine carburetor open. From the system menu.

Don Szczur

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From the previous post, one other note. The trim setup is at a resolution of 1 for rudder, 1 for aileron, 1 for elevator, and 3 for throttle (I had this much highter for the first flight and reduced for finer trimming after rough trim was achieved).

By the way, I could really feel a big difference when flying the DX-18. The plane felt much more connected. Not sure if its the gimbals, the speed or the feel of the radio in my hands. Anyway its just somthing I noticed right away.

- Preflight setup. This is really a neat feature of the DX 18 which provides a preflight checklist. The one of note is the fuel plug. Tony can attest that I normally keep my fuel plug open except when on a hot runway between rounds at the NATS. When people pick up my plane they sometimes close the fuel line plug, and when I go to start on the next flight, it takes me a minute to realize why the motor won’t start- because the plug is closed….

- Dual rate and expo- very simple single screen access point


- Throttle curve- easy to program. I reduced the power in the mid-range for a better feel around the rolling circles (horizontal circle) and cruise speed resolution around mid-stick.

Don Szczur

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- Servo Travel- I try to keep my mechanical adjustments close, and use the travel adjust to only a percent or two for perfect throw alignment of the control surfaces.

Don Szczur

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Mixing

R-E/A mix- a convenient single screen access point to the knife edge mix features. (rudder to elevator and aileron)

Mix 1 is throttle to elevator for down line mix (to prevent the airplane from pulling out on its own during a down line at idle) Notice the offset of -38 percent- I like a smooth transition of this mix, starting at about ¼ throttle or less and working its way to full engagement at idle. That way any increase in throttle will not cause the plane to “gallop” in the pitch attitude. Also note that the trim is “inhibited” that way the mix won’t change if I change my engine idle trim.

Mix 2, Throttle to rudder. Note I have just a little left rudder with low throttle. This is to offset the right thrust and keep the nose pointed straight down in a vertical down line.

Mix 3 Throttle to aileron. This is a third down line mix to keep the plane from rolling slightly during a down line (or spin entry with the idle low).


That's it for the overview!

Don

vbortone

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Hi Don,
Probably you could help me. I got the following questions:

1. I am interested to get the Spektrum DX10t tray radio. I assume that the DX18 and the DX10t programing and capabilities are the same. Do you know if this conclusion is correct?
2. Does the DX18 has the capability to do the stick position switching like the JR 12X? Screen 91
3. Does the DX18 has the capability to do the snap programing using stick position like the JR12X? Screen 31
I assume that you don't mind to respond. I know that you have been using JR so probably you are the best person to help me. It is obvious that the choice for pattern pilots that have been flying JR is to get Spektrum in the future so we don’t have to replace all the RX.

Thanks,

PatternFlyer

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Since Vince posted here, I will hold my e-mail to Don. LOL

Ihncheol

Don Szczur

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Section 8-17 of the 10t manual covers Analog switch Setup to allow all sticks and pots to be used as kick point to turn on functions like mixes. The instruction manual is located here: http://www.horizonhobby.com/pdf/SPM2800-Manual.pdf This provides capabilities of this radio in detail. You can compare it to the DX18 capabilities at http://www.horizonhobby.com/pdf/SPM18000-Manual_EN.pdf

The DX18 does not appear to have the same snap programming menu item as the 12X. You can check with the Horizon support for more details on the particular functions you are seeking. To be honest, I only tried stick position switches once (about 20 years ago) and did not like the feel of it (coming out of the snap precisely).

The DX18 does have the capability to turn on and off mixes using sticks- so you just mix more or less control by using a stick as the switch. After playing with the mix functions some, I was able to set a snap condition by stick position through P-Mixes. For example, mix 2 rudder to elevator, rate set to get the elevator deflection you want on a particular flight mode, operated with "rudder stick" as the switch. It gets a bit complicated when setting up multiple flight modes for positive and negative snaps, but appears do-able.

Regards,
Don

vbortone

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Hi Don,

I appreciate very much you taking the time to explaing and find out the information for us. Clearly the DX10t has the capability to do the stick position switching but the manual really does not give too much details how to do it and if can be assign to the flying modes. I will assume that could be done. I use the stick position swich during snap similar to you. Just reduce the amount of elevator when getting the rudder to some position so I start with more elevator and gets reduced when the rudder reach some pre-programend position. The JR12X screen 31 makes this very easy up to 5 different snaps and can be assign to flying modes. I always wanted a tray radio and looks like this is the very first oportunity to have it with full service in the US. Also I won't nee to replace the RXs. Now, I need to make a decision.

Don Szczur

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Information applies to latest models of Spektrum transmitters. Will work up a few hints on setting up snap and spin curves on the transmitter if interested. DX 18, IX-12, etc.