PicoPilot with Telemaster Electro

[cmoulder]

I have the PicoPilot NAT version installed in my Telemaster Electro and, for the first time, today I entrusted it to fly a simple box pattern and then return to the "home" waypoint and circle. PP is far from being dialed in, but it was a rush all the same watching my plane fly itself.

As it was flying, however, it did a fair amount of porpoising and the throttle was surging with a RRRRRRRrrrrrrrrRRRRRRRrrrrrrrrrRRRRRRRR, even though I had done a few flights and had it trimmed nicely for level hands-off flight at a quite moderate throttle level, and the pots were set quite low -- approx 25% -- and then even lower on subsequent flights. I had no wing rock, so the Nav board was working great. But it seemed that the Alt and Thr were working at cross purposes, although the disagreement was a lot less noticeable when the plane was circling over home waypoint.

For you guys who have a lot of experience with this, some questions:

1) Is it better (and simpler) just to set the throttle yourself and forgo the Thr portion of PP? When the throttle is surging as I described, would it help to turn the pot up? This I did not try today.

2) I have very little elevator and really don't want to reduce it even more, but will this help reduce the porpoising?

3) It occurred to me that the Alt sensor inside the model might be experiencing a pressure increase as the model speeds up -- therefore responding with "up" elevator -- and then senses the lower pressure as the model slows down, while at the same time the throttle is responding to the pitot tube pressure changes.

4) Is the "lifting tail" surface of the Telmaster models such a good idea for autopilot systems, considering that the flat-bottomed airfoil on the tail, like that of the wing, also provides more lift as the speed increases and therefore causes pitch changes?

I have the Telemaster Sr (not yet assembled) and am having second thoughts about whether it is the most suitable candidate for PicoPilot, or if it would work better if I just made a flat-plate elevator for it and chucked the stock one...

[Jack Crossfire]

Doing personal research on the Picopilot. It would be great if U could post a 1024x1024 photo of the Picopilot board. Main curiosities R how many gyros & accelerometers it has.

It looks like it's designed for extremely stable planes like motor gliders. It probably can't respond fast enough to fly a Telemaster.

[dmgoedde]

Icebear seems to be a Pico NAT expert. I bet he could really help out here. From what I have read, Pico NAT should work great on your Telemaster.

Some general thoughts from my general autopilot experience:
1) Sometimes porpoising is due to gain too low, rather than too high. It depends on the frequency. Fast porpoising = too high gain, low frequency can be from gain too low. Too low gain means the system is always lagging and trying to catch up. You might accidentally have your thinking backwards, like I have done on a number of previous occasions. Turns out once I though gain was too high, whereas in fact it was too low by a factor of 8x!
2) Normal RC speeds have much smaller affect on dynamic air pressure than I once thought. I doubt that increased engine is causing a cross correlation effect on baro alt hold.

[Tom Harper]

Moulder,

Where's the CG? The Telemaster will fly OK on RC with the horizontal stab loaded. But that may be marginally stable and give problems in Auto flight. Try adding a little weight forward. Just a thought.

Tom

[cmoulder]

Okay, guys, thanks very much for the input.

Jack, I would be most happy to do a good macro shot of the board, but in order to make the 3 boards a single unit, PP stacks them and shrink-wraps them so it is not really accessible for a photo.

dmgoedde, good info there -- nice to have a little rule-of-thumb to work with. I have already pestered Bjorn (icebear) and Jeff (workshop) enough in PM's, so I will wait for them to stumble across this and respond as they wish.

Tom, yes my CG is at 4-1/2", almost at the 4-1/4" forward recommendation, so I will scoot it forward a little and see if that helps. But it is very nicely balanced in its pitch attitude when flying straight and level.

-- Bob

[icebear]

Bob,

Just stumbled across this thread... :)!

Unfortunately, I don't have experience of the "T" part of the Picopilot myself (just the "NA"), BUT I definitely think the Telemaster is a suitable airframe. A lot of people have had good results with the Picopilot and the TM so to me it sounds more like a setting up issue. My Viking looks a lot like the TM and it works very well.

Here is a few thoughts;

- Try minimizing elevator throw but let the servo have full travel to use its resolution
- Set the gains on the 'Pico-Throt' and Alt-E units quite low to start with
- Make sure the gain pots are correct in your unit - there have been reports of some that are reveresed - ie full clockwise means the lowest sensitivity (easily tested on the ground)

I dont think the 'flying stab' is an issue here, but as Tom suggested a change of CG might also help...

Very nice TM mods you have made, by the way! Really liked the skis too...

/Bjorn

[cmoulder]

Ha! Glad you found me, Bjorn! :)

If that is the case (with the possibility of pot reversal) then that is something to check as well.

I know from Jeff's thread that this is a good airframe, but I did note that at some point he had put the Thr on a separate enable switch, which suggested to me that he also had a struggle with it. I had the pots very low on my 3rd flight Friday morning, possibly as low as 15%, although as you know that is rather subjective as there is no scale for reference... more of a "feel". So I think I will try dmgoedde's (Dean of attopilot, right?) suggestion and try dialing up the gains to see what happens.

With regard to servo resolution, I set it up carefully for maximum servo resolution for the (minimal) control surface range. I have the exact throws as suggested by Jeff, except for the elevator. The elevator had such minimal travel that I moved the linkage in one hole on the elevator so that I wouldn't "run out of elevator" on the maiden. At this point, it has as little control surface deflection as I would care to fly it with manually, with 100% servo travel.

At first I was thinking the flaps would be useless, but they do indeed shorten the take-off run quite a bit. This is good since I have the ailerons and rudder on a "Y" harness and ground handling is a lot different that I am used to... with the right thumb rather than the left. Better to get airborne quickly.

HAha, I can imagine a Scandinavian having a keen appreciation for the skis. I enjoy flying from skis, so as long as the wind permits, snow and cold do not deter me from flying. I fly aerobatic planes with skis, and they don't seem to affect their performance at all if they are adjusted correctly.

Okay, then. I will test fly tomorrow if the winds subside (not likely!) or early Monday morning since I am working later hours, and will let you guys know what happens.

-- Bob

[workshop]

I, too, noticed that the Pico throttle and the PicoNAV fought each other. I reasoned that the Telemaster climbs (too much) with an increase of throttle and that since the two units don’t communicate electronically, oscillations begin. I removed the Pico Throttle and used a failsafe throttle setting.

I’ve used the PicoPilot NA on the Senior Telemaster and the Electro Telemaster and think that the plane is an ideal platform. I have video that looks like it was shot from a blimp and, once set up, the control authority is very impressive. The stab only adds to total lift - any moment arm effect is countered by the much greater lift of the wings.

BTW the Electro is still my main machine. With flaps, it leaps into the air and drops from the sky. Smooth and solid in the air... I'm moving the PicoPilot to a sailplane for a long range voyage over water where there isn't much to see for a long time. As a PicoPiloted camera platform, a Telemaster is hard to beat.

Jeff

[cmoulder]

Thanks much, Jeff. I will play with the gains a bit more, but I think the Throttle on F/S may be the way to go. Having one less variable has got to simplify the process. I have read every word I could find concerning PP and I remembered this being mentioned. I just didn't know if bypassing Thr had become your standard set-up.

Now, I just have to make sure that I have enough throttle to fly upwind with reasonable speed. :rolleyes:

BTW, I didn't have a separate GPSr onboard for tracking, but I flew my route a couple of times and PP seemed to hit the marks pretty darn close both times. I came up against the "chicken out" urge a couple of times; those waypoints seem a lot closer on the map, for sure!! :D

-- Bob

[wadiprawita]

Dear cmoulder,

Is there any user manual or maybe integration manual of picopilot that You can share with us, so we have further information how it works ?

-doni-

[cmoulder]

Dear cmoulder,

Is there any user manual or maybe integration manual of picopilot that You can share with us, so we have further information how it works ?

-doni-

doni, the general information on how it works can be found here: http://www.u-nav.com/faqs.html

The manuals are in pdf form and if you contact sales@u-nav.com I think Mark will e-mail them to you. I don't think there are any state secrets contained in them, but they are copyrighted and I'd prefer U-Nav to disseminate at their own discretion. But really, none of the manuals contain specifics concerning the sensors and circuitry, so they won't be helpful in that regard.

The wind is howling today from the northwest, so I will just do some ground testing (or, in my case, deck testing) on the Alt gain, per icebear, and will likely go ahead and bypass Throttle. If Jeff can't get it to work, I sure as hell can't. :o

-- Bob

[kd7ost]

Here's something to consider and hopefully it's worth at least .02.

In our RC planes we optimize the motor (Engine) thrust so that as we vary the throttle we don't get pitch changes. We tend to use elevator and high throttle to gain altitude.

In full scale, you use throttle to gain altitude and elevator is used to slow the plane down more or less.

When I set up my Pegasus1 aircraft I had to do a little re-thinking and made some small tweaks. First I should state that I still use elevator for altitude control in the Pico Pilot. I use the Pico NavR, and Alt E boards. But throttle still comes into play. I built in a degree or two of additional up thrust in my engine so that under full power, the plane will climb. But not too steep as to stall. I don't need to touch the elevator to get up to my target altitude. The engine does it for me.

When I want to stay at altitude, I set the throttle to cruise speed and enable the AltE. Naturally the Alt E is set up with my elevator to keep me at altitude with minimal porpoising. The amount of porpoising I see is contingent on winds aloft. If it's dead calm, I don't see any. If I'm in a head wind, the plane lifts higher at the set throttle RPM and gains altitude due to high air speed with the head wind. The Alt E drops the nose to compensate and a slight porpoising begins. The amount varies depending on the speed of the head wind. More wind = more lift = more Alt E response. This is normal and is to be expected because I'm not doing anything to maintain air speed.

A similar thing occurs when I'm in a tail wind but works the opposite and slows down the oscillation response curve. Less air speed, less lift, less air over control surfaces etc. It still stays in the altitude range I need though. It isn't a fault of Pico Pilot but of my application that this occurs. Again, if I used a air speed sensor I would be in better shape. My missions don't find it critical to be better than it is. (Don't get me wrong, most of the time it's hard to even perceive it from the ground) Only in watching a video downlink do I see the pitching take place if the camera is fixed at the time of pitch changes.

Anyway, You may want to experiment with the amount of upthrust in your engine to get things closer. I would do it this way.

Fly the plane across your position at a low altitude for ease of observation. No Pico enabled or anything. Just standard RC. Pull the throttle down until you are at a slow speed, but fast enough to maintain flight speed and altitude. Trim the elevator for hands off flight. Straight and true. (Winds must be pretty calm) Get a few passes like that in front of you to make sure you have it set right.

On a subsequent pass as the plane gets across in front of you, roll up to full throttle (without touching elevator) and see what happens. Does the plane pitch down? Does it pitch Up? Does it stay straight without gaining altitude? My guess is that your set up will gain altitude quite well. Maybe too well.

I would want to start out with the engine thrust so that there is ever so slightly an altitude gain with full throttle. It might be that when the throttle is activated by your Alt T that there is too much upthrust causing the plane to quickly overshoot the altitude you want. The response is to cut the throttle and the plane drops back down.

I don't know. It will take some careful analyzing in your set up to see what is happening and how to fix it. I still have to admit I don't use throttle for altitude control as I just don't need that in a big gas plane.

If you think wind may be punching the BP sensor there is an easy fix. Take a length of fuel line, maybe 8 to 12 inches and push one end on the sensor port. Let the rest curl around inside the fuselage so there is a space that varying winds don't have any effect on. It will still read the ambient BP.

Dan

[rpage53]

I still have to admit I don't use throttle for altitude control as I just don't need that in a big gas plane.
However, that is the best way to go for smoothest flight. Throttle controls altitude and elevator controls attitude (pitch). If you have both operating for altitude control you'll be very lucky to get away from hysterisis that causes oscillations. Especially if you are only using a barometer for altitude estimation.

Elevator should always be trimmed for a little up. Everyone knows to use up elevator to climb, but a little up trim in level flight allows throttle to alter altitude smoothly. On descent, up elevator allows a slow, high drag descent that is also easily controlled with throttle to get smoothly and safely on to the runway.

These are generic comments, I don't know these particular control boards.

Good luck,
Rick.

[kd7ost]

However, that is the best way to go for smoothest flight. Throttle controls altitude and elevator controls attitude (pitch). If you have both operating for altitude control you'll be very lucky to get away from hysterisis that causes oscillations. Especially if you are only using a barometer for altitude estimation.

Elevator should always be trimmed for a little up. Everyone knows to use up elevator to climb, but a little up trim in level flight allows throttle to alter altitude smoothly. On descent, up elevator allows a slow, high drag descent that is also easily controlled with throttle to get smoothly and safely on to the runway.

These are generic comments, I don't know these particular control boards.

Good luck,
Rick.

Good points. I should also state that I don't use my planes for fully autonomous flight even though they have the capabilities. In my Agriculture work I use semi autonomous flight. Since I'm viewing the downlink as I fly, (high) over a field and center up, I keep the pilot in the loop. Due to derogatory "Range to waypoint" issues in a GPS unit, it won't get me centered over a field and well framed by itself. The pilot does a better job. The autonomous flight comes in to play in the event that the failsafe is activated. This returns the plane to my location.

I still think it prudent to ensure the motor thrust line is dialed in the best it can be in any of our cases. This will allow the flight dynamics to be within the capability of the altitude unit to do its job without overworking. The thrust line is as critical as the rest of the control surface throws and response and is many times overlooked in the integration process.

Dan

[cmoulder]

Thanks for all the good information! Dan I really appreciate your real-world working knowledge in this area.

Actually, on my maiden flight I noted that once I trimmed the elevator for level flight, the plane would descend noticeably when increasing throttle. So I put a couple of washers under the motor mount for additional upthrust. The other day, it was a lot better, climbing slightly as you described under full throttle. So I don't think it is a thrust angle issue. Right thrust also seemed good, with no pull to the left or right when the model was pulled vertical under full throttle. Seems this is important as well since it would cause PP to have to correct that yaw constantly.

Already I have the throttle bypassed, so I'll work with that for now. Failsafe on all surfaces and throttle level checked out fine -- as well as the all-important PP enable! However, good thing I gave it a thorough check because I have the flaps set to utilize the full servo range for down travel, so at 0% they ended up in the middle of the range, which would not have been good in F/S mode. Now they stay up when in F/S.

Next time, I will get up really high and observe the reaction in "enable" mode and then F/S when all is satisfactory.

-- Bob

[kd7ost]

Great Bob,

Sometimes I just play around with the plane, try different things that might be the issue and the answer comes to me. Maybe that will work for you. I do know that as soon as you introduce a wind component when trying to dial it in, its much harder to get consistent results.

Then when you get it set perfectly on a dead calm day, then go out and fly in wind you'll see differences again.

On our small level of plane and components, there is a measure of "good enough" that you have to live with. Obviously you don't want to stop short of getting it the best you can. The difference in wind, aircraft loading, speed, control surface size as well as throw, etc all come in to play. We throw a lot of factors into the fray.

Dan

[cmoulder]

"Good enough" is good enough for me. :)

I was happy to see that even while the throttle surge and porpoising were going on, it was maintaining altitude and hitting the marks, so with the throttle steady and the porpoising greatly reduced, it will be just that, "good enough." I guess I got lucky on the Nav set-up because there was no wing rocking that has been mentioned elsewhere.

I do plan to do the Sr. Telemaster next, with a G20ei, and a gyro to stabilize the camera in the roll axis. I want a platform that can stay aloft and loiter for about an hour, so gas is the only way to go. Seeing how well the F/S worked today (at least on the deck :rolleyes: ) makes me think I will go with just the NA version of PP for the Sr. Tele. Thinking now -- pure speculation at this point -- that the pylon mounting scheme for the engine might work, using vibration isolation on both the engine mount and the wing mount, with PP in the nose and camera system attachment point at CG, so camera and video could be changed without having to jigger with balance.

Eventually I would like to go with a twin-boom pusher with (semi-?)symmetrical airfoil, such as your Pegasus, for more speed and for stability in the wind. Do you have plans for the Pegasus, or is there something similar in kit or ARF form?

I have read your discussions of the practicalities of flying wings and am pretty sure that I want, eventually, the flexibility and payload capacity of a gasoline pusher.

-- Bob

[cmoulder]

However, that is the best way to go for smoothest flight. Throttle controls altitude and elevator controls attitude (pitch). If you have both operating for altitude control you'll be very lucky to get away from hysterisis that causes oscillations. Especially if you are only using a barometer for altitude estimation.

Elevator should always be trimmed for a little up. Everyone knows to use up elevator to climb, but a little up trim in level flight allows throttle to alter altitude smoothly. On descent, up elevator allows a slow, high drag descent that is also easily controlled with throttle to get smoothly and safely on to the runway.

These are generic comments, I don't know these particular control boards.

Good luck,
Rick.

Thanks, Rick. This also seems to make sense... trim for a little "up" then PP puts in a little down to maintain altitude. Since I've already bypassed the throttle, it should be easy to tame it down. Hopefully. High-lift wings probably operate most predictably at a constant throttle level, so I'll figure out what throttle level is best for moderate winds (say 10-15 mph) and then set the F/S for that and note the stick position.

Just wondering if U-Nav has higher sampling rates, data smoothing and data exchange between boards on their more expensive units. Probably in the FAQ's but I'm kind of dazed from reading FAQ's right now :o

Weather looks good for test flights tomorrow morning, so I will try to keep in mind all the good info I've gotten from you guys. I hope to have on-board video for the flights.

I can't thank you all enough -- what a great community!! :D

-- Bob

[DiveBombDave]

You mentioned a TM senior with a G20ei as your next platform...

I re-maidened my TM Sr with G20ei today, first tank of gas at break-in (not needed per manual) mix of 32:1 and I flew for 30 minutes on 7 ounces of gas, and this was with steep climb and dive repetitions, and loitering at an airspeed that would make the finest lipos sweat. :)

The 18oz tank looks tiny in the plane, and after I get to 40:1 then I should be looking at possibly and hour and a half.

Sorry if slightly off track, I just wanted to comment how well gas can treat you.

Dave

[cmoulder]

Good looking set-up, Dave!

Yes, I think that for long-duration flights there is no substitute for gasoline engines. I fly electric, glow and gas, and I cannot see electrifying a bird of that size -- just cannot afford the batteries, and, if I could, field charging is difficult under the best of circumstances. Glow is a kind of netherland for planes of this size, so the G20 is the obvious choice. At least for guys like us!! :D :D

But at this stage -- for learning to use and understand PP, programming maps, downlinking video -- the TM Electro fits the bill, and I can fly it at a local field that is literally 2 minutes from my home, but has strict engine size and noise limitations. At first I thought I had bitten off too much, but it is starting to all come together.

Gas, I understand; the small challenge now is tweaking PP, and the bigger challenge soon will be the gyro-stabilized (roll axis) camera system. Got a Futaba GY401 and am trying to comprehend that at present.

But I have to ask, What is the sling-type apparatus on the belly of your TM?

-- Bob

[kd7ost]

"Good enough" is good enough for me. :)

I was happy to see that even while the throttle surge and porpoising were going on, it was maintaining altitude and hitting the marks, so with the throttle steady and the porpoising greatly reduced, it will be just that, "good enough." I guess I got lucky on the Nav set-up because there was no wing rocking that has been mentioned elsewhere.

I do plan to do the Sr. Telemaster next, with a G20ei, and a gyro to stabilize the camera in the roll axis. I want a platform that can stay aloft and loiter for about an hour, so gas is the only way to go. Seeing how well the F/S worked today (at least on the deck :rolleyes: ) makes me think I will go with just the NA version of PP for the Sr. Tele. Thinking now -- pure speculation at this point -- that the pylon mounting scheme for the engine might work, using vibration isolation on both the engine mount and the wing mount, with PP in the nose and camera system attachment point at CG, so camera and video could be changed without having to jigger with balance.

Eventually I would like to go with a twin-boom pusher with (semi-?)symmetrical airfoil, such as your Pegasus, for more speed and for stability in the wind. Do you have plans for the Pegasus, or is there something similar in kit or ARF form?

I have read your discussions of the practicalities of flying wings and am pretty sure that I want, eventually, the flexibility and payload capacity of a gasoline pusher.

-- Bob

I think you'll get it working very well. You're doing the part of UAV design called system integration. I've never heard of anyone that dropped in the parts and it worked perfect right off. It takes a little time to get the gains and the aircraft set up to work well sometimes.

There are no plans for the Pegasus. I posted some details and after the fact pictures on a thread here.

http://www.rcgroups.com/forums/showthread.php?t=792387

They don't show much though.

Dan

[cmoulder]

Glad you pointed me in that direction, Dan. I had gotten numerous hits on the Pegasus1 but never clicked on that particular one.

Excellent build. But I was a little surprised by the Clark-Y airfoil, thinking that was only employed in trainers. However, the lift is superior and you don't need that much speed anyway... and there appears to be no dihedral, so better for crosswinds.

I stated earlier that the inside of my Tele Electro looks like a rat's nest, but I sort of bundled up sets of wires going to the same general locations and it really starts to make sense, at least to me. At first, the interior of the model looked very spacious. However, after getting all the components in there it started to fill up really fast. It really is a bloody miracle the CG came out right on target -- I sure didn't plan it! Makes me appreciate even more what Jeff did with his, what with the additional telemetry and tracking downlinks, and the modular boxes.

-- Bob

[DiveBombDave]

Good looking set-up, Dave!
But I have to ask, What is the sling-type apparatus on the belly of your TM?

-- Bob

I knew you'd notice that.... it's a "drop plane" for a 3-4lb remote controlled 18" tall skydiver named "Lucy." She can pull her own ripcord and is therefore freefall capable and stable in freefall like a human, and can steer and flare her 48" scale ram air parachute. We drop from 700-800' and steer for a circle in front of us. I wish I had some good pics of Lucy - after she gets her shock absorbing servo arms courtesy ala buggy steering, I'll dress her up and snap some poser shots. :)

There is normally a box attached to the fuse bottom to cradle her pack/chute, and the strap comes under her belly and hooks in the other side. You can see the servo and release pin beside the fuel tank in the above photo.

Dan's Pegasus is widely considered the flagship of custom built 20lb ships, especially for a twin boom pusher. I'm actually president of his fan club, shirts are $12, wearing one now.

Dave

[kd7ost]

Glad you pointed me in that direction, Dan. I had gotten numerous hits on the Pegasus1 but never clicked on that particular one.

Excellent build. But I was a little surprised by the Clark-Y airfoil, thinking that was only employed in trainers. However, the lift is superior and you don't need that much speed anyway... and there appears to be no dihedral, so better for crosswinds.-- Bob

I stay pretty old school with my wings. Trainer style I mean. Flat bottoms with modified leading edges. High lift with gentle pitch is what I'm after.


Dan's Pegasus is widely considered the flagship of custom built 20lb ships, especially for a twin boom pusher. I'm actually president of his fan club, shirts are $12, wearing one now.

Dave

:p ;) You're too much Dave, Thanks

[cmoulder]

Pretty cool, Dave. I'll bet that's a hit at fun-flys! :)

Well, nearly disaster for me yesterday :(

I had everything set to go, plane on the runway after going through all the checks and ensuring that the video was on an recording. Rate switch set properly, 'enable' green light checked, then disable again, control surface check, throttle blip... and I was walking back toward the flying station, thinking along the way to remember to put flaps down... and the plane just started the TAKE-OFF ROLL by itself! :eek:

Wow, major panic time. It stayed along the ground, and up elevator did not respond, nor flaps, and I thought for sure it was going to keep going and end up in the Hudson River or maybe in Connecticut. So I just gave it full down elevator, and that seemed to work. This all happened in the space of about 4 seconds. It hit the weeds slightly over the edge of the hill and I thought it was crunched big-time. Miraculously, the only damage was to the front part of the 'cabin' area of the fuse, where the wing attaches. No damage at all to the wing (and that precious motor pylon), and the nylon wing bolt heads had sheared off very cleanly. The camera was not damaged, but the servo was a goner. Doesn't hurt so much when it's a $15 servo. Bottom line: it is already repaired and ready to fly again.

What happened?? :confused: Well, I didn't figure it out during the 4 seconds of total panic, but I gave it a lot of thought, obviously, in the next half hour. It was as if the model's RX had briefly gone into FS mode, so it was something with the transmitter. The power switch was on, so it wasn't that. 'Enable' switch was up (off). No 'mix' indicator on the screen, so it wasn't some funky mix combination and another switch that was inadvertently toggled to cause it.

I don't know if this is possible, but here's what I think happened. A few weeks ago I got one of the 3s lipo batteries for the transmitter. It was freshly charged and putting out 12.5 volts. I am guessing that the Futaba TX has got a regulator that caused a brief thermal shut-down, thereby sending the RX into FS mode, hence the unanticipated take-off.

Does this sound reasonable? After that scare, I really want to nail this down before flying again. After repairs, checked it out on the deck again and all seems back to normal. :o

-- Bob

[kd7ost]

I stated earlier that the inside of my Tele Electro looks like a rat's nest, but I sort of bundled up sets of wires going to the same general locations and it really starts to make sense, at least to me. -- Bob

I know what you mean. I started some years ago, (after building big planes) to treat the wiring harness like it was a model within a model. I work with electronics including putting new equipment in racks of satellite systems. I learned a lot about wiring harnesses.

I guess if you could open the hood of your car and take a look at the wiring harness. How all the wires bundle neatly, take corners gently, and are long enough to do the job but not longer. I try to replicate something like that in my planes minus the looming of course. I try to place all the parts and mount them in the right place then work the wiring into place. It's easier to do in big planes of course. Cutting the servo leads and soldering them to other wires can be a bit dicey though unless you are skilled at soldering and what heat shrink to use. That stuff from radio shack is killer on wires. I don't use that stuff at all. You can get softer material from electronic supply stores that stays soft so it doesn't cut into the insulation and cause a sharp fatigue point at the ends of the shrink. Tape is a no no for me. Then I use small cable ties to hold it together but you have to use care here too. You can't tighten down as much as you can with RC wires because the insulation on those is really soft. You'll cut into those and create weak spots as well. The ties have to be just tight enough to hold the bundle together without causing damage.

Anyhow, it's pretty easy to do if the plane is big enough to get your hands into. Small fuselages are a little tougher to get things to fit in. They do tend to have excess wire tucked inside someplace. Most times on smaller planes it's just not worth trying to fit a custom harness into.

Dan

[cmoulder]

Man, wiring up satellites has got to teach some good habits!

I think I learned the most from gassers, seeing stuff come loose and things break from vibration that I had never seen with electric or glow. As a result, my attachment and securing techniques have really improved a lot.

My thinking is the same on wire length, ie shortening and soldering when the time comes for a 'big' installation, but this being my first attempt to integrate an autopilot I didn't want to nip/tuck the wires when the length might be needed later.

Good mention on the Radio Shack heat shrink tubing. I hadn't thought of that one, and that knowledge will come in handy for the gasser application later.

-- Bob

[kd7ost]

I don't know if this is possible, but here's what I think happened. A few weeks ago I got one of the 3s lipo batteries for the transmitter. It was freshly charged and putting out 12.5 volts. I am guessing that the Futaba TX has got a regulator that caused a brief thermal shut-down, thereby sending the RX into FS mode, hence the unanticipated take-off.

Does this sound reasonable? After that scare, I really want to nail this down before flying again. After repairs, checked it out on the deck again and all seems back to normal. :o

-- Bob

Wow, scary moment. It's possible that it was as you described but I think not likely. The transmitters are designed to operate with 12 volts and have regulators to drop everything down lower. I don't know the max voltage you can put in, but I suspect it's higher than what we use. You can put in 8 standard AA batteries, the carbon zinc style and when brand new they will put out 1.6 to 1.65 volts each. This would give you a voltage potential of 13.2 volts with no load, (off) sitting there and this is OK. The transmitter only puts out ~750mw so the current draw stays low as long as you don't put in a real high voltage. Thats the way it works, but it's not to say you don't have a transmitter problem. I would suspect something else but it wouldn't hurt to put the stock Nicd pack back in during testing just to make sure.

Did the plane go into full failsafe? It would be helpful to know your set up. What gets enable and to what extent if the receiver does go in to failsafe? Pico Pilot enabled? Throttle to what setting etc?

Dan

[kd7ost]

Man, wiring up satellites has got to teach some good habits!
-- Bob

Oop's, I meant satellite ground stations. I've never seen a satellite up close. Just the ground equipment.

Dan

[cmoulder]

Dan, yep in retrospect I realized it was in full FS mode because the motor wasn't running at full throttle, but about 56% of stick position per FS setting, and all control surfaces are neutral. (If anything, I learned that the FS settings and trims are very good.)

FS does enable PP as well. I re-checked this a few times. Come to think of it, the plane was probably heading for DA001.

I don't know squat about electronics -- just basically how to plug stuff in and a rudimentary knowledge of what the major components do -- and that's the only explanation I could come up with.

Anyway, got the NiMH TX pack charging now...

-- Bob

[kd7ost]

I guess all I can suggest is to play it over in your mind to see if you can spot something that happened. Complete massive range checks with the motor disconnected. Inspect the receiver antenna and unsure that it hasn't become damaged in the routing or exiting of the fuselage. And it might be good to even concider interference if you were at a club setting but I tend to shy away from that explanation. Intereference is an over used excuse by many people that just don't know what happened. Only blame external forces when you are sure there are no internal ones. Otherwise it stands the potential to happen again.

And if you already know this stuff I apologize. I'm just throwing things on the table to chew on.

Dan

[cmoulder]

Thanks, Dan. Yeah, I know a lot of this, and am familiar with the old crutch, 'interference'. I've seen guys use this when they were flying an aerobatic plane too aggressively, yanked the elevator and tip-stalled/snapped-out near the ground. I hear them muttering "interference" when I know darn well what happened. Some people just don't understand that a plane can tip-stall at 80mph.

And I have seen real interference -- which is very jerky and twitchy -- and the plane just took off smoothly, so that wasn't it, for sure.

No, I really want to find out what happened. I also checked the TX antenna... okay... and the model memory again, just for the heck of it, and the mix settings to make sure all were INH or NULL. In fact, a little while ago I went out on the deck, tied the plane down and went through the same procedure, with the motor battery hooked up as well, and just let the plane sit there for 5 minutes to see what would happen. Nothing.

Well, I'll do the same set-up at the field next time, with full range checks again, just to make sure.

EDIT: Hmm... I thought of something else. I had the video on, and it is a 2.4Ghz, 1-watt system, so perhaps when my back was turned my transmitter antenna was shielded and RFI from the video TX initiated the FS??? Doesn't seem likely, though, because a couple of times during earlier test flights, with video on, the model was a looooong way off and there were zero glitches.

Probably some doofus noob-boob something I did. If I figure it out I promise to fess up.

-- Bob

[kd7ost]

Cool,

I'm sure you'll get a handle on it.

I've had trouble before with cheap RC plugs and connectors. Some of the ones from "Expert" and another brand I can't recall right now have pretty sloppy fits. The "universal" ones. You can tell primarily from the extreme ease that they can be inserted and extracted. I never use those in my planes anymore as I have had problems sporatically with them. I will only use the JR Gold or Futaba heavy duty ones. I also only use the heavy duty switches in my UAV's unless they are the small electric ones. I do have a source for the best RC connectors I've ever found in my favorites at my home PC. I'll post a link when I get home tonight for those. They don't go together real easy and they don't come apart real easy either. But more than tight fit shells, the pins and sockets are designed for a tight fit with lots of surface contact. They are the best. Again, you may already have this covered. I also use a small length of clear heat shrink after tested and assembled to ensure they can never come apart without my help.

In the mean time, you can power up your plane minus the motor, and twist, pry and teak on the connectors to see if something glitches out.

Dan

[cmoulder]

One thing's for sure -- the more things there are in a plane the more things there are to go wrong. Worth checking, but I THINK all is well there, since I'm using the Jomar/EMS heavy switches with the Smart-Fly pin/flag switch for GPS and a good toggle switch for GPS program/activate. Futaba heavy duty all-round, but this seems compromised a bit by the FMA in-line buffers which use a surprisingly light-duty wire, VERY light-duty. I could imagine a stout digital servo burning one of those out in 1/2 second if even slightly stalled. Good thing none of the control surfaces/linkages are anywhere near binding...

Oy, too bad because yesterday morning and this morning were perfect for flying. Yesterday the calm such as you see the 2nd day after a storm, and today the calm right before the storm, overcast but dead calm.

But what happens, happens, and there will be more good days ahead.

-- Bob

[kd7ost]

I'm converting to JR for my next project just because of the buffer requirements for my Futaba. I prefer my Futaba layout and ergonomics but I hate having to match the 3 volt parallel pulses to the TTL devices. Too many pieces in the chain. I did make my own buffers though as I wanted to have heavy wires and a simple robust design.

I don't use digital servo's in my uav's. they are power hogs for the application. I do use good analog servo's though. metal gear trains on the critical flight surfaces and coreless high torque versions. They operate very efficiently with low power draw.

Dan

[kd7ost]

What kind of pack, (voltage and cells) do you use for the reciever and servos? The Pico pilot doesn't always tolerate 5 cell fully charged packs. The PIC chip in use is a 5 volt unit. Put 6.5 volts into it and your RC system is fine but it can be too much for the Pico unit until the voltage drops a little. I use a special 5 volt regulator with a 5 cell pack to illiminate any issues there.

Dan

[cmoulder]

Dan, I, too, have been considering switching to JR, mainly because of Futaba's dismal handling of the roll-out of FASST, but also because it seems they go out of their way to make components incompatible with other manufacturer's equipment, and they still don't have servo programmers like Hitec does. Seems you have to figure out a work-around or buy another piece of gear to do anything slightly out of the ordinary. This servo buffer issue may be the last straw.

Agreed, I didn't see the need for digital servos considering the small control surface deflections, and looking at those buffer wires convinced me that was a good decision. I may not know much about electronics, but I know you can cram only so many electrons through a small wire.

I am using the 2s 2000mah lipo on Rx, about 8.4v freshly charged. However, that goes through a Smart-fly linear regulator that puts out right at 6v, in fact 5.97v when I checked it with the voltmeter. The same model regulator is used for GPS power, set at 5.2v. If I recall correctly, the PP manual stated that 6v into the receiver is fine, and that PP has its own 5v regulator.

-- Bob

[kd7ost]

Cool Bob, Sounds like you have all the bases covered. I just checked the specs on Unav's site and they do say 5 to 7 vdc.

Dan

[cmoulder]

ps I meant to ask, on your Pegasus1 that looks like a Fuji 34 or 43cc, and I'm wondering who makes those engine mount elastomers? Are those the ones you still use? -- Bob

[kd7ost]

ps I meant to ask, on your Pegasus1 that looks like a Fuji 34 or 43cc, and I'm wondering who makes those engine mount elastomers? Are those the ones you still use? -- Bob

I'm heading home from work here in a few minutes. I'll look up my links at home and post those too. I don't recall the site right off.

Dan

[cmoulder]

Thanks, Dan. No rush -- just gathering the bits gradually for the TM Sr.

Probably I'll just stick the engine on the nose, but that's definitely not firm yet. The pylon arrangement has its advantages.

[kd7ost]

OK, The engine in my Pegasus1 is the Fuji BT32A. It's been replaced with the BT32B. In some ways, I sized the Pegasus around this specific engine for a couple of reasons. I liked the magneto ignition instead of the electronic ignition of some engines. With a magneto the engine will run as long as you give it gasoline. No battery required for the power hungry electronic ignition. The weight trade off wasn't there for me. Yes an electronic ignition is lighter. But not by the time you add the ignition module and enough battery power to keep it running half a day or even less.

The Fuji engines have the ATM (Automatic Timing Module) which gives you spark advance through the RPM range making low end to high end better than other magneto engines.

It also has a spring starter options which minimizes gear needed to start it. You need a pretty massive starter and good battery to start these gassers. Hand starting is an option with this engine. Not with Zenoah engines.

The Zenoah G26 doesn't have a spring starter option.

The unit was first mounted with 3/4 x 3/4 inch rubber mounts. They seemed stiff enough till I got that big thumper running. They were too soft. Above idle and up to full speed they worked great. But once you dropped the RPM the decrease in frequency caused that engine to become a blur. It had trouble running and the vibration was severe. I went to a stiffer, shorter and larger diameter mount and that brought it on line just fine. I got the mounts from Estco. http://www.estcoenterprises.com/index.php
I don't recall the part number but the ones I use are 5/8" thick X 1 3/8" diameter. They use a 5/16" x 18 TPI stud. You would have to call them to ask which ones those are. They have changed there web site and I can't tell which ones I have now. I also see they now have a 50.00 minimum charge so things have changed. You might look for a different source. Just keep them fairly short and large in diameter like mine and you should be OK.

And one final site I promised. Here are the connectors I like to use and keep on bench stock. Multi colored is nice to keep things straight at the parts where the plane comes apart. Only JR and Futaba high end wires are as good as these.

http://electrodynam.com/rc/conn/index.shtml

Dan

[kd7ost]

Did you say it was going to be the 12 foot Telemaster?

Dan

[cmoulder]

Good info, Dan, and excellent links. You are a wealth of info! Those are some industrial-strength connectors.

I am assuming that the vibration isolation works effectively to keep it tame enough for PicoPilot... :rolleyes:

I like the rubber goods, but don't know if I need $50 worth. A while back somebody turned me on to McMaster-Carr for a lot of this sundry mechanical stuff and they sell small quantities to hobbyists. I looked at their website today and they had a wide variety of rubber and polyurethane elastomers, and an excellent durometer chart to give a sense of the relative hardness/elasticity of their materials.

The TM Sr is the 8-footer, not the 12. Many of the ardent TM aficionados think a G20 is overkill for the 8-footer, but it's the extended flight time I'm after and the G20 is one of the few small gassers out there. It does not look at all out of place on Dave's TM Sr. I think the EI will be okay because I am able to fly all day with a DA-50 and a 1500mah NiCd. (Smart_fly also has a Li-Ion and ignition regulator combo that works great, recharges quickly). Probably will use a 24-oz tank, so loiter time at moderate throttle should be quite good. Thinking now that I won't put it on CG (reserving that for the camera gear) but a bit ahead with the tank mounted vertically to keep the mass close to CG. Those Walbro carbs have such good draw they don't care where you put the tank. Probably will modify the fuse so that the camera gyro level/pan/tilt will be partially recessed (3-4 inches) for ground clearance.

If I put the G20 on the nose, I will mount it cylinder up, and therefore exhaust up. This will keep the fuse belly clear and also reduce ground-level noise. Higher pitch prop, too, for lower cruising rpm = less noise.
-- Bob

[workshop]

It is hard to keep up with you guys! :cool:

Re: SmartFly Regs... Remember to set the voltage under load. I use a 10 Ohm 5 Watt ceramic resistor across the output while I set the voltage with a voltmeter.

Jeff

[DiveBombDave]

The zenoah g20's EI is crazy power hungry by comparison to the DA50, then.... the only saving grace is that it runs off 1s lipo for fast charges/swaps.

I found some info on it's euro version at toni-clark.com that said "fly 1.5hrs on a 2450mah cell" and I thought they were being very reserved with that estimate. But the 30 minute flight I put in used over 800mah out of my 2100mah cell! So their math is right on.... I was wishing there would be a way to generate an amp of 4v onboard for the system.

But, those single 2100 lipos only weigh 2oz each, so an extra one or two wouldn't be felt. I bought a pair of single cells from truerc specifically for this engine, and soldered up some JST/BEC's to them. Their tabs were nickel coated so I could use normal solder/flux and a 15w iron - I tried soldering a cell from a TP2100 pack I busted up with no luck whatsoever. But anyway, I just swap them out when I fill the tank, and keep one on a charger.

It's the perfect gas engine for the TM Sr - I believe it would hover with larger surfaces. And I know it can harrier! :eek:

Oh, and btw, I have been running a 3s2000 lipo in my Futaba 9CAP with no repercussions.... I would be careful to investigate your recent failsafe incident with extensive range testing (sans prop) with special concerns to the video tx antenna location vs servo wires (? maybe). That may be a guess, but I'd put a fivespot on the radio not being 'it.'

Dave

edit - A SOLAR CELL! An "amp of 4v"...... it'd be a good sized set of cells to make 4watts, but could be easily done.

[cmoulder]

It is hard to keep up with you guys! :cool:

Re: SmartFly Regs... Remember to set the voltage under load. I use a 10 Ohm 5 Watt ceramic resistor across the output while I set the voltage with a voltmeter.

Jeff

Jeff, yeah that took me a little while to figure out :confused: as I said before, not knowing squat about electronics. I will have to get that resistor at Radio Shack to save some time. I just had mine plugged into the RX which could easily handle the voltage and then shorted the little prongs to change the regulator output voltage. Voltage checked under load on the RX, so I'm hoping that's fine.

-- Bob

[cmoulder]

Dave, hmm... maybe I should try it with a CH ignition, seeing as how the Z ignition sounds quite inefficient. Hey, a spark is a spark, no?! :D

Glad to hear the 3s lipo gave you no probelms with the TX. But if it wasn't that, it only deepens my mystery.

I hate to blame interference, but I am starting to wonder if perhaps interference could have triggered FS briefly. Our field is very close to a major Metro North train station that is known to put out massive radio signals, and there is the occasional REAL glitch. It was only in FS for a very few seconds, and the stick DID finally respond to the down elevator command. I remember when I was going through the FS ground check by turning off the TX, it took a couple of seconds to regain control after turning the TX on again, so maybe this is possible.

I may never know, but if it never does it again that'll be fine, too.

-- Bob

[kd7ost]

I get the same from my Futaba. When you power it back on it takes a second or two before you hear the beep. It goes through some kind of power on self test before it turns the RF on. It isn't instantaneous.

Dan

[cmoulder]

Dan, which JR are you considering?

With so many folks switching to 2.4Ghz there are some good deals on the 10x 72Mhz, but I may bite the bullet and wait for a 12-channel. With the addition of pan/tilt/shutter(/zoom?) the channels get used up quickly. But 10 would suffice.

Any reason to switch (or not switch) to 2.4Ghz TX? My video TX is 2.4Ghz so that sounds like 1 reason right there.

-- Bob

[clolson]

I think I've heard (here?) of people successfully running 2.4Ghz video with 2.4Ghz RC gear. I had some trouble when we tried ... both systems stepped on each other. I think the key is to have good distance between the RC receiver and your video transmitter, and not have too much power output on your transmitter which could potentially "blind" your RC receiver. I've also had problems with high power video/data transmitters jamming my gps. Being a software guy, my solution has been increasing the antenna spacing and/or reducing the power of my transmitting devices.

Personally I've had 72Mhz, 900Mhz, and 2.4Ghz systems all stepping on each other when I put too much transmission power too close to another receiver ... there's more to worry about than just frequency separation it seems.

Regards,

Curt.

[kd7ost]

Dan, which JR are you considering?

With so many folks switching to 2.4Ghz there are some good deals on the 10x 72Mhz, but I may bite the bullet and wait for a 12-channel. With the addition of pan/tilt/shutter(/zoom?) the channels get used up quickly. But 10 would suffice.

Any reason to switch (or not switch) to 2.4Ghz TX? My video TX is 2.4Ghz so that sounds like 1 reason right there.

-- Bob

9 channels is going to work for me. I'm going with the 9303 R770 or its synthesized counterpart the R790. I'm sticking with 72 Mhz. I too run 2.4 Ghz on the down link. I'm keeping the two frequencies as far out of band as I can. I think when guys try desperately to mix 2.4 Ghz AV next to a 2.4 Ghz receiver they just have money burning a hole in their pocket and too much bench time or aren't concerned with range at all. The frequencies are not the same granted, but they are close. The 2.4 Ghz AV transmitter will increase the noise floor to some extent for the RC Receiver limiting its ability to pull in weak signals when you get farther away. That's just a given in the RF world. Having it just work up close doesn't matter to me. If it works at a distance, then it will work up close.

Mixing 2.4 Ghz RC with 900 Mhz downlink will probably be fine. In my case I used to mix 72 Mhz with 900 Mhz downlink. But in my crop work I ran into some rare cases where at a distance, I would quickly lose video link. Digging around showed me that some field equipment used to control irrigation systems etc were being run via RC by 900 Mhz with radio modems. Those were putting out RF at 900 Mhz causing my AV signal to drop out once I got out a little ways. It wasn't common but after I switched to 2.4 Ghz AV things cleaned up. Your mileage may vary. There are also 2.4 Ghz Radio modems around population. Also there is a lot of 2.4 Ghz computer network equipment etc. I don't fly around population though so haven't had issues with that.

Dan

[cmoulder]

Well if a 9-channel will do it, then I may just stay with that, also with the 72Mhz variety.

Good news about the 'auto FS' problem -- the mystery is solved!!

I went to the field this morning, fired everything up and did extensive checks, then got the same problem again, but only after the plane sat there for a couple of minutes, after everything was turned on. Hmm...thought it was some switch assignment issue because the enable light stayed green all the time and the enable switch had no effect, just stayed on... much head scratching... What the hay, the only other thing it could be, the only thing that had changed, was the disconnecting of the throttle. When I bypassed PP I simply unplugged the lead (with buffer) from the RX and put the ESC plug in its spot. THAT was the problem!!! The buffer was still plugged into PP and caused the FS. You electronics guys can explain why... I just know it is.

Got in some great trim flights this morning, and the Alt is settled down nicely. Just a little porpoising downwind but rock-steady upwind. I have video which I will post later, as well as GPS tracks.

YESSSS!!! I am grinning from ear to ear! :D :D :D

-- Bob

[kd7ost]

Great find. Good to nail it down.

Dan

[cmoulder]

Huge relief to be back on track!

I am editing the video of the final flight this morning, where PP flew the small rhombus-shaped test route, and the whole thing was smooth as silk. Bank angles are perfect, no wing rock and barely perceptible, if any, porpoising. Wind was a quartering crosswind about 5-10 mph. This puppy is darn-near dialed. Alt gain is about 20% with the throttle stick at about 62%, although these are very subjective numbers that won't really mean anything to anybody else setting up an airplane.

Wow, what a rush to see this thing working correctly!

-- Bob

[DiveBombDave]

Glad to hear of your success! Let's see that track....

Dave

[cmoulder]

Glad to hear of your success! Let's see that track....

Dave

Here ya go, Dave! I was using a Garmin ForeRunner velcro'ed to the wing, and I had the data smoothing set a bit too smooth (I use it mostly for jogging) so the points are a bit far apart. But you get the idea -- PicoPilot was right on the money. :D

-- Bob

[icebear]

Congrats Bob!
Great to see that you got everything dialled in and nice to see the track...
Looking forward to the video :D...
/Bjorn

[cmoulder]

Congrats Bob!
Great to see that you got everything dialled in and nice to see the track...
Looking forward to the video :D...
/Bjorn

Video: http://www.rcgroups.com/forums/showthread.php?t=830024#post9304313

Sorry, it's rather huge, but looked so crappy otherwise. Maybe I need some tips on format and compression. Maybe?

-- Bob

[workshop]

What a great feeling huh?... People say I have a dream job (former rock drummer now special effects company owner) but the thrill of robotic flight is just as good as the rush provided by the highlights of my day job. :D

I seem to be working so I can fly... :o

We are all happy that you have joined the PicoPilot club! Great work!

Jeff

[icebear]

Thanks Bob!

Nice video - very good reception to your groundstation at all times!
Great that you can really see when the WP's are hit and you have a quite good bank angle there...

I am just using Windows MovieMaker (free) to compress my videos. Works quite well if you dont compress too much and I guess you could get your file down to 15-20 MB with reasonable quality. I am sure there lots of better options though...

/Bjorn

[cmoulder]

Thanks, Jeff, for your inspiring TM threads, and for the idea of moving the motor to a pylon for the TM Electro, and to Bjorn for showing what can be done with a little technology and a little daring. And to UAV Grand Master Dan for freely and patiently explaining things and for showing us what a real workhorse UAV looks like. And to all the others who chimed in with help and advice, you've helped make the UAV experience seem like a great fraternity.

I've got a LOT to learn, but you guys have gotten me off to a good start. Already it is a rewarding experience that appeals to my interest in flying and imaging, and fortunately I like to figure out how to make things work. And even if my technical expertise is somewhat lacking, there is always the solid grasp of the conceptual purpose of the gizmos involved. I can see that being a stubborn problem solver is, without a doubt, a prerequisite for endeavors such as this!

Well, I can see now that I need to have a 'mission' such as Catalina Island or Lighthouse, and my first one will be a lot more modest. When fair weather returns I think I will shoot for Potato Rock, which is only about 1.8 miles round trip. I got the still camera link working (downlinked as video), so I've got to modify the camera mount and put a servo on the shutter button, and then I'll be ready for that one.

Oh, and I need to test-fly my little box pattern in FS to make sure it is working!!

-- Bob

[kd7ost]

Hey Bob,

I finally got as chance to download and view the video. It looked great. Nice job. It looked very good. Congratulations.

Dan

[cmoulder]

Today I made the mount for the still camera, a Fuji FinePix F50 which produces 12-megapixel images, and also video of 640x480 at 30 fps. This should make good pictures and video, but that remains to be seen. High-quality still images are the goal, so I hope at least for this much.

It was made with 1/8-inch plywood, and I robbed an old foamie of the micro servo for the shutter release. For the shutter, channel 9 was still open, and the trainer switch is assigned to trip the shutter. I changed out the Futaba 3001 servos for some 3305's (metal gear, higher torque) for more rigidity and to handle the heavier camera, which weighs 6.1 oz. I had to shorten and solder the A/V cable that came with the camera, and apparently my soldering was pretty good because the image downlinked perfectly despite the fact that I took out the ferrite ring built into the A/V cable.

Here are some pics of the installation.