SeamusG

I'm setting the throws of my Aeroworks Edge 540T. Da "book" days that the aileron throws are different up &down (2 servos separate channels). Elevator throws are different too (single servo). Aileron low-n-hi rates differ by 42%. Rudder low-n-hi diff is also 42%. Elevator low-n-hi diff is 22%.

The Edge is 7 lb 5 oz (empty fuel tank)plane powered by an OS 91 FX with a 14x6 APCsport prop. Primary type of flying will be precision / pattern stuff - and boring holes in sport mode. Ihave no real desire to dance on the 3Dside of things 'cause the brain can't imagine let alone fly those "maneuvers".

I could toss just about any reasonable (close enough for hand granades approach) setup on the radio & mechanicals so that Ican go out and fly but Idon't want to do it the same old way. The guys a Aeroworks (Rocky and his crew) did a lot of good work to come up with these specs so I'm gonna try to honor their work effort and try to get it right "out of the box". OK, call this a learning experience ...

And - I get confused / overwhelmed when Ihave a bunch of different ways to attain the same goal ...

The DX7 allows me to Travel Adjust the servo travel - up to 150%. As best Ican tell there is no need (maybe a little)for Sub Throw that would eat up any of the total throw. The dual rates allow me to knock down travel low below 100% or up to 125%.

So, what's the general approach to this setup (maybe call it a best practice)? Use 100% of servo travel to attain high rates and use the dual rate to knock it down for low rate spec? Use 100% of servo travel for low rates and overdrive the servos for the high rates?

Thanks for your ideas.

And if it helps, the servos are Spektrum DS821 low-end digital bits with a 5-cell NIMH 2000 mAh pack - Rx is a AR7000.

BuschBarber

My Feedback: (2)

Anytime you set up a new Model, the first place to start is to set up your Servo Arms and Control Horns. You want the distance from the Center of the Servo Arm to the hole the Clevis is attached to, to be about the same distance the hole in the Control Horn is from the control surface. Set the Servo Arm at 90deg to the Servo Case, hold the Control Surface at Neutral, Measure and Install the Pushrod. Power up the Tx and Rx. Reset the Model Memory to Factory Default. Set the Servo Direction for each Servo. Install the Servo Arm as close to 90deg as possible. If it is not quite at 90deg, use a small amount of Subtrim to move it to 90deg. The Control Surface should be at Neutral.

Most Servos rotate 60deg in each direction, from Neutral. They will not move the full 60deg unless the Travel or End Points are set to the Max (150deg, for example). Move the Sticks back and forth and measure the Deflection of the Control Surface. Adjust the Travel, for each Control Surface, to the maximum you would possibly want the Deflection to be. When using the Travel Adjust, you can set different values for Up, Down, Right, or Left. This is where you can correct for any Mechanical Alignments that may cause the Deflection to be different for each direction. Use the Rate Settings to set your High and Low Rates. You can also set Expo for each Rate.

If you are using a separate servo for each Aileron Half, for example, you can connect each servo to a different channel and mix them in the Tx. In this way, you can Match each Aileron Half to one another, more easily. If you connect each Aileron Servo to a Y Harness, you have to use Mechanical means to Match each Aileron Half Deflection.

SeamusG

I have most stuff in a "default 5 channel setup" model on my DX7 with all of the basics used. Most of my planes use 5 with a couple that use 6 channels (split elevator requiring 2 servos) All the basic mix stuff is set up in the default including a throttle kill mix.

My question is: do ya set up the mechanical trim (servo arm hole & horn hole) using 100% servo deflection for the low rate settings and use the radio features to adjust for high rate settings? Or, do ya set up the mechanical trim using 100% servo deflection for the high rate settings and use the radio features to adjust for low rate settings?

BuschBarber

My Feedback: (2)

The Control Surface is only going to move as far as the Mechanical Setup let's it. You cannot Increase the Deflection with the Transmitter.

Set up the Mechanics so that you have the best Leverage Advantage and more throw than you need. Set up the Travel Adjustment, in the Tx, to give you more throw than you need. Use the Dual Rates to give you the High and Low Rates recommended for the aircraft. Add Expo if desired. Increase or Decrease the Rates after the Trim Flight. Keep the SubTrim to a Minimum.

SeamusG

Thanks for you input!

Another perspective - from the tech support guys at Aeroworks (also national 3D competitor) ...

"I typically set up the servos to have full rates with the travel adjust at 150%, this will give you the best resolution from the servo. I then use the dual rate function to dial the servo down for low rates. "

The more I hear the less I know for sure [:@]

I agree that there is a mechanical limit - the point where the leading edge of the control surface contacts the trailing edge of the fixed surface stopping any additional rotation around the hinge line. If the mechanical limit does not provide sufficient movement for the max throw on high rate - oh well.

Then it's on to the servo arm hole location with respect to the control horn hole location. If 150% travel adjustment will allow for full movement of the control surface to achieve high rate max deflection with existing hardware - great. If not - new hardware - I'll get a longer servo arm to change the mechanical (dis)advantage.

Slowly I turned, step by step, inch by inch ...

AndyKunz

The AW guy is right. You want the servo to move as much as possible. This helps spread the pot wear more evenly across the surface. It also makes the centering of the surface more accurate and more repeatable.

Andy

airbusdrvr

But if you setup 150% and then use dual rates to cut it to 30% to 40% to get the throws you want, then the pot wear issue is still there. The linkages will have to be set up to allow the full servo travel and then give the control thows you need.

BarracudaHockey

My Feedback: (11)

If you use any sub trim you can't max out the travel adjust. If you use metal or single arms where you dont have the luxury of rotating them 90 degrees at a time till you get a good alignment you're probably going to end up using some sub-trim. If that happens and you max out your travel adjust you will hit the mechanical stop and get differential throw.

If you're not competing and trying to get that last 1 percent of perfection out of your setup, a good compromise is setting high rates up at 100 percent travel adjust, and low rates at some lesser percentage of that.

SeamusG

In a perfect world - 150%. I used to have a T-shirt that had "It Depends" on the front. Yea - just ask me a question, I dare ya ...

I appreciate the input.

DadsToysBG

My Feedback: (35)

Heres how I do it. Set the travel at 130%, then come back to hi rates and set them. Then set the low rates. Use a pitch gauge if you have one. A lot depends on if you want IMAC or 3-D. I never go over 130% when using digital l servos for fear of stalling them. Never over ride a servo, this can stall a servo and cause a big drain on your battery. All the new dig servos have great resolution. dennis

SeamusG

Let this be a formal announcement - I AM GOING TO START TAKING DRUGS! [img]../../punymce/plugins/emoticons/img/trans.gif[/img]

I have 2 Aero-works pitch gauges. I believe that they both need a bit of adjustment with a BFH005 - that's a big f____ hammer - 5 lbs. Neither settles to a consistent reading at rest or at full throw. The final reading is more dependent on the speed that the stick is moved than the actual angle. Grrrrrrrr. Cloths pins DO NOT make for a good foundation for a pitch gauge as the swing plane of the needle is not at 90 degrees to the horizontal plane.

Of course, neither aileron records the same pitch at full throw - off by several degrees.

In the attached pic, the gauge is clamped to a straight edge resting on the table. The pic has been rotated so that the straight edge is horizontal. So what's that say about the pitch gauge?

Going back to a ruler and may the degree wheel be damned ....

SeamusG

I spent some quality time finishing off the static trim settings on the Edge 540T.

I started out setting the "Travel Adjust" at 130% for ailerons, elevator and rudder. Using a 12" square I adjusted the servo arms (swapping amongst a bunch of different OEM and aftermarket bits), the servo arm hole location and the control horn hole location until I got the throw "mechanically" close to the (non-3D) high rate specification. For the ailerons this resulted in using completely different servo arm / horn hole locations for some totally unknown reason. The control rods are withing 1/2 mm. But it worked out. The High rate throws were hit spot on. Then the dual rate feature was used to dial back the control throw to the low rate specification.

Time to maiden. Thanks for the help.

For the morbidly curious:

Aileron setting:
Travel adjust R (aileron channel) L 115%, R 130%
Travel adjust L (aux1 / flap channel) U 130%, D 100%
Note: Too bad the DX7 uses L/R for AILE and U/D for Flaps - more drugs please ...
No sub trim
Aileron mixed with aux1/flap at 100%
Dual Rate: 100% high, 65% low

Elevator setting:
Travel adjust D 140%, U 120%
No sub trim
Dual Rate: 100% high, 85% low

Rudder setting:
Travel adjust L 130%, R 130%
R 15 sub trim (pull-pull and the servo arm didn't align at no trim)
Dual Rate: 100% high, 70% low

Kmot

My Feedback: (24)

Geez.................... [&:]

I just finished programming my DX7 tonight on a Four Star. I set all the servo arms at 90° (is there anyone who doesn't?) and adjusted the linkages so that all control surfaces were at neutral. I left the default setting for servo throw at 100%. This was my 'high rate'. For low rates I just cut everything back to 50%. Then I set my expo at 20% on low and 60% on high. Simple. The control sticks will make any other adjustments as needed "on the fly".

DadsToysBG

My Feedback: (35)

. If one flight service is off i 'll use the travel adg. to make them the same. going the the one that is more i bring it down to the lower one. the go thru the process again it to sure that they both got up and down the same. Checking both the low and high. If the gauge is off as long as the number is the same on both sides it works. Only flying ccan tell you if the throws are what you like. Expo is my friend. Dennis

SeamusG

Dennis - you are so right about "only flying can tell you ...". Hopefully today

DadsToysBG

My Feedback: (35)

Have fun. Let us know how it goes. Dennis

SeamusG

Successful maiden - all on low rates. 3 clicks of up elevator - none for rudder or aileron. 15% expo wayyy too sensitive - will up to 30-35. Roll rate maybe 540 / sec. Too fast for pattern stuff so I'll slow it down. Excellent directional stability. CoG seems very good though I haven't run it through its paces yet. All in all - very nice. Won't be messin' with the 3D throws any time soon. Glide angle very nice - makes for nice smooth 3-point landing. Two times when the peanut gallery watches landings - maiden flights and dead sticks.

Got a fuel supply glitch limited flights to 1 - drat.

Kmot

My Feedback: (24)

Congrat's!

DadsToysBG

My Feedback: (35)

when you start your balance flying you may find that it is a bit nose heavy. thats why the elevator trim. One why to test is to fly into the wind and full throttle and then quickly chop the throttle and see how fast the nose drops. dennis

onewasp

_________________________________________

Not as often today (computer radios) but we used to set the servo take off position to create throw differential .
Elevator on a number of Pattern ships had more up than down, similar to differential on ailerons .

Some of us still do for certain planes .

Ever wonder why the wheel servo arm has spaced holes ? That's why .
Before you even measure I'll bet you that one set of holes is exactly 120 degrees .

I realize that you are beyond this now but I wanted to answer your question since you seemed to imply "Who would do such a thing?".
I fly precision and my routine set up has differential for ailerons; more up than down on elevator; and more left rudder than right .

We are talking single digits in degrees .

Just like race cars . Everyone sets up differently . Yet we all have the same goal .

SeamusG

onewasp - AW recommends that both the ailerons and elevator have differential as their initial setup. Travel adjustment has pretty much eliminated the need for the round servo arms.

If someone wants to dance with the round servo arms what kind of control rod servo arm attachment is preferred?

Kmot

My Feedback: (24)

I'm well familiar with the servo wheel and mechanical linkage being your only means of adjustment, I started flying r/c in 1974.

But today I would think only someone who has an interest in flying retro for some reason would still use that type of setup. Computer radios have made things much better in my opinion. I also realize 'different strokes for different folks' and all that.

SeamusG

When I started training a couple of years ago, a friend from race track activities held up a trainer and a DX7. After you learn to fly and are ready to buy your own stuff "you WILL buy a 2.4 radio and the DX7 is an excellent place to start". I followed his recommendation.

Why did I explain this? I had no CLUE what all the bells and whistles were used for. Why did Spektrum spec out the features of the DX7? MIx? What the heck is mixing? Flaps? What are they other than things bird do with their wings? Differential - em, that's the thing in the back of a rear wheel drive car that.l Dual rates - duh. Exponential? Is that exponential equations that I loved to solve?

Insult to injury - the DX7's manual sucked as a "user's guide". It's decent as a reference manual that describes how to affect a certain control feature of the DX7 but as far as telling the (newbie) user what feature they need and why - well, being kind - it SUCKS 'cause that's not why it was written..

kmot - you have been speaking the language for nearly 35 years more than I have. I'd love to understand the evolution you've been through but it ain't gonna happen. Part of my learning has been to record what you guru's know as "best practices". That's what this thread was trying to do for me - identify a best practice for setting up the servo & Tx before I head to the field for a maiden flight.

Also, as our club has a training night every Thursday - free training (planes & Tx & buddy box) - I hope that I can help them get with the program quickly. If the student brings a plane we help set it up. These guys are just like me - jumping into the pool with your cloths on.

Just got off the horn with a club member (past board member of our club) and he's trying the use split channels to control 2 aileron servos. Flaperons get in the way. Ailerons don't react correctly. He's been successfully flying this plane with a Futaba with a Spektrum module and wants to just use the DX7. This afternoon should be fun!

Just sign me "trying to figure it out".

Kmot

My Feedback: (24)

Seamus, this could go on like a novel!

My experiences are not all that remarkable. There are sooooooo many more guys here with lots more to tell then I.

But briefly, my first radio in 1974 was a Cirrus 4-channel from Hobby Shack, and it was mfg'd by Futaba at the time. NiCd battery packs were an extra cost option. The Tx had trims, which were slider switches. That's it. No servo reversing switches, no end point adjustments, no mixing of channels, no low battery alarms, no model memory, no nothing. Just basic control and everything else had to be done mechanically with the servos and linkages inside the model. IE, if you needed to reverse a servo, you moved the linkage over to the other side of the servo arm. If you needed end point adjustment, you had to play around with where you inserted your linkage connector on the servo horns and control surface horns. If you wanted differential you used the round servo wheel that had holes spaced in patterns so you could accommodate the differential. Ailerons were normally operated by a single servo. If you wanted mixing, there were mechanical linkages that could be purchased that would accomplish some degree of mixing, but I never used them so I don't know how well they may have worked. Throttles typically used a "over ride springs" thing that allowed for the servo travel on a limited carb and so would not stall out the servo and drain the battery. It was a very time consuming, and sometimes head scratching deal to get your radio set up like you needed it.

Today with a computer radio, you install the servos and linkages, that is the end of the mechanical work. Then using your computer radio you "beep" your way to the perfect setup.

SeamusG

Hey - guess who's sitting on the living room floor with radio, manual & AW Edge540T  - just readin' and playin' ... oh it does this when I do that - and on it goes.