RunRyder - Setting up Spektrum DX7 in Belt CP troubles

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e-E-Sky Honey Bee- Lama- Belt CP- E-Smart > Setting up Spektrum DX7 in Belt CP troubles

Melnic
Senior Heliman
Location: Columbia, MD,USA

Just tried my new Spektrum DX7 in my Belt CP this morning.
My first thing was that it was not passing a 30 pace range check.
I have the 6100 mounted w/ the antenna pointed out the left and right side. The antenna sticks down from the heli about half way down the skids. My field has a wooden deck platform for helis to takeoff and land from so the heli was about 6" off the ground on top of the wood for the range check. I'll have to try it again and take some measurements to see how far it works though. I'll also need to try the test outside the heli to see if it's the way I mounted it. One thing I could not find in the manual as I did not have lots of time was about the transmitter antenna. It has that bendable joint at the end. I had mine so the antenna tip was straight up. Is that right?

Next issue is the swash sensitivity. It was WAY too sensitive for hovering and messing w/ the ATV did not seem to do anything. I wanted to reduce the max throws in the servo. What setting should I use? Dual rates? One thing that was funny is that even though I only had 30% dual rates, it was acting like 90% where, moving it near the neutral position had little change, then when I took it to about half one direction, the heli moved quickly to the far throws (scary). Sensitivity was so numb near neutral throws and sudden at 50% stick throw, that just landing it was a challenge.

Any advice on these 2 issues?

06-27-2008 03:03 PM

TJinGuy
Elite Veteran
Location: Socorro, NM - USA

Well I can't help with the range stuff or even the radio setup but I can give you my thoughts on de-sensitizing your heli.

It has taken me a while to learn what I believe is the proper way to adjust a helis cyclic speed and that is in the swash menu under the aileron and elevator settings. I don't know what the DX7 calls them but my Futaba calls them A and E. By adjusting these numbers, one can simply adjust the total travel of the CCPM mixed servo actions for each cyclic movement. SO I would leave dual rates and expo at their neutral positions. Leave the EPA settings at their neutral positions and then adjust the total cyclic movement to your liking. That way you don't learn to use an expo modified setup and the stick movements will stay linear throughout the entire throw.

- Chris

Variety+spice+life+supporting_paper_towel_industry=
King2+Rex450+Protos+Concept30

06-27-2008 03:56 PM

Melnic
Senior Heliman
Location: Columbia, MD,USA

Will that affect my pitch curve? I still want my max/min pitch to be +10/-10 (or is that set up for too much range?)

06-27-2008 04:10 PM

TJinGuy
Elite Veteran
Location: Socorro, NM - USA

No this is all related to the CCPM mixing in the radio and that is why it is the best approach. When you setup the pitch on the radio, you change pitch CCPM setting in the swash menu to adjust for the total pitch range. The aileron and elevator settings are right there next to it and are separate to it in terms of CCPM.

That is why this is the best approach. If you were to adjust the EPA or even the servo links to achieve a "slower" heli, that would also mess with the rest of the head setup, including pitch.

- Chris

Variety+spice+life+supporting_paper_towel_industry=
King2+Rex450+Protos+Concept30

06-27-2008 04:21 PM

tryan02
rrProfessor
Location: Canton, Missouri

Range check of 30 paces is definitely a problem antennae up is Ok but theoretically it should be parallel with the receiver antennae. I will only guess that you have a problem elsewhere need to check power to reciever no loose connection from ESC you know all the regular stuff.

I setup my heli at the pitch recommended in the manual and let her rip just learn to fly it no expo no dual rate. I do use EPA only because it controls the piro rate on my gyro . I wanted it faster.

Wheres greggor he could give the ccpm swash settings for a DX7? I think there around 50 on my futaba heli's?

I learned to fly on a BCPP so twitchy ridiculously fast helis are what I know.

Canton MO backyard flying club
Club President
Team No funds left.

06-27-2008 04:34 PM

HOMEPAGE

Gregor99
Elite Veteran
Location: Western Wa

Chiming in here with much recent DX7 range checking experience. For clarity the DX7 range check is 90 ft (30 paces). As we know the antenna can't be collapsed like 72hz radio, so the range check is performed by lowering the power output of the TX. If the aircraft doesn't pass this test, don't fly. As I noted in another thread, my max range check was about 127 using the same proceedure.

Things that can affect range, off top of my head (and duplicating some of Tryan's thoughts)

1) RX placement poor. Too close to noise electronics like ESC or BEC. Transmission blockage due to frame parts.

2) Bad or poorly performing RX or TX. Hard to tell unless you have second RX

3) Broken antenna wire on the RX (common with these)

4) Noisy test enviroment.

Any chance we can get some hi-res pics of your electronics placement?

--------------

On the swash mix thing, Chris is right. I use the swash mix values to set the max pitch range for cyclic and collective. ELEV and AILE percentages control the cyclic and should be the same number. PIT controls the collective travel.

I'd recommend not setting these to arbitrary numbers found one either mine, or someone else's DX7 setup. I'd recommend you set these based on your measurements with a pitch gauge. My process is to find the mechanical limits of collective, then cyclic, then the combination of the two. This is is the max setting.

Then I will dial back the collective to what feels right in the air, and measure the pitch. That is currently at 9 for me. Next I repeat that process for the cyclic. Continue dialing back the swash mix settings until I've got the feel I'm after then take a pitch reading.

This process does require that you can handle an over responsive heli. If you have any concerns, use the reverse approach. But first get the max swash mix settings that will max the head mechanically. Then, using a pitch guage, set the collective to + or - 9. Cyclic should start at 6 or 7. Adjust both values up from there using the swash mix (PIT for collective) and (ELEV AILE together for cyclic)

Canton MO backyard flying club
West Coast Chapter

06-27-2008 05:17 PM

Melnic
Senior Heliman
Location: Columbia, MD,USA

Yes, it's when I press the button in the back of the TX that it then looses the signal and goes into it's throttle default.
I'll see if I can get some pics up of the radio setup.
I'll change my pitch range to +9/-9.

What do you mean by "Cyclic should start at 6 or 7"?

06-27-2008 06:21 PM

Gregor99
Elite Veteran
Location: Western Wa

Quote
What do you mean by "Cyclic should start at 6 or 7"?

Just like the collective (left stick) applies positive or negative pitch to the blades, the cyclic (the right stick) also applies patch to the blades. The differences is that the collective applies the same pitch the blades uniformly. The cyclic applies pitch only in two specific areas. 1 area is postitive and other area which is 180 degrees from the first area is negative. This is what causes the heli to move forward/back and side to side. Because is slight delay in blade response, the pitch is applied to the blades 90 degress prior to the desired change to the rotor angle. Using a clock as an example if forward is 12 oclock on the rotors and 6 is backward. Say you want to move the heli forward. Apply forward right stick (collective). The pitch change begins to go negative at 9 oclock, peaks between 10 and 11, then is back to normal at 12. At the rear, the pitch increases starting at 3 oclock, peaks between 4 and 5, then is back to normal at 6. The result is the entire rotor pitchs forward, causing foward motion.

I take my cyclic readings in the peak areas. I don't shoot for a specific number but rather based on what feels best as long as it doesn't exceed the mechancial range. Also be aware that things like EXPO, headspeed increases/decreses, flybar wieghts, and lighter flybar paddels all affect cyclic response. So the measured pitch is just a starting point. Fine tuning must be done to match the heli's response to the pilots skill level and preference.

Lastly the heli feels too docile consider trying a higher swash mix. Of all the things I mentioned, I prefer using the swash mix to set the cyclic sensitivity. Seems more linear and predictable than using EXPO.

More info, starting section 11.

http://www.w3mh.co.uk/articles/html/csm9-11.htm

Canton MO backyard flying club
West Coast Chapter

06-27-2008 06:51 PM

Melnic
Senior Heliman
Location: Columbia, MD,USA

Thx,
That is what I thought you meant about the cyclic pitch. Just wanted to confirm.
I guess I need to fiddle some more on the bench before flying it again next week. Off to the beach this weekend

I remember my first heli (30 sized Hirobo Shuttle), I didn't understand the 90 degree rule and flipped the aileron and elevator servos cause that is what made sense to me. Good thing my test pilot checked that before taking off.

David

06-27-2008 07:05 PM

Melnic
Senior Heliman
Location: Columbia, MD,USA

Pic of temporary AR6100 install.
Note: When I did the range test, the heli was on top of a wooden platform (deck) about 6" off the ground.

06-30-2008 04:06 AM

Gregor99
Elite Veteran
Location: Western Wa

Was the RX in this position during the test?

Canton MO backyard flying club
West Coast Chapter

06-30-2008 04:12 AM

Melnic
Senior Heliman
Location: Columbia, MD,USA

Yes,
That was also approximatly my view of the heli as well when I hit the bind button to lower the signal strength.

06-30-2008 02:38 PM

Gregor99
Elite Veteran
Location: Western Wa

OK Mel a few more tests for you.

1) Determine the range you are currently getting before making any changes. It'd be good to know how close to 90 ft you are getting.

2) Next retest with the antenna on the TX in the 90 degree position. In my test, that extended the range little bit. During this test, also take a measurement to see if there was any improvement.

If the Tx antenna adjustment doesn't help enough, its time to contact Horizon. If you have a second Rx to test, that would save you having send in both the Tx and the Rx.

Canton MO backyard flying club
West Coast Chapter

06-30-2008 05:44 PM

Melnic
Senior Heliman
Location: Columbia, MD,USA

Ok, will try that.
I have an AR6200 that I bought early last week as well that should be in this week. I'll test that one and post my results.

06-30-2008 08:42 PM

Melnic
Senior Heliman
Location: Columbia, MD,USA

I was able to reconfigure the Heli and test it out last night. My servo settings were all out of wack based on what you guys said. My ATVs were set non-symetrical. Especially the aileron where my troubles were. I flattened those out and then made some adjustments to the linkage lengths to get the swash all straight mechanically first. My swash throws were above 8 in when giving full right aileron so that had much to do with it. After fixing things, I did not totally set up the pitch but worked on the swash throws and such. Mechanically, I had about +/- 7 or 8 on the swash throws. Dialed in the Dual rates to turn that down to +/- 5 for both aileron and elevator. Flew it last night and it is much better. Only had time for one quick range check before I was called in for dinner. This time, the heli was flat on the grass an the antenna was just like the photo. I got 1 paces (30 yards about). Moving the xmitter around, I had dead spots when the antenna was pointed at the heli. Will try again tomorrow.

07-01-2008 02:43 PM

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