I have attempted EDF twice and am completely terrified of them. I've been having problems with flight and am trying to figure out what is wrong with what I'm doing. Whenever I fly the EDFs (fly meaning take off and crash) the aircraft has a tendency to try and roll itself over. If I don't give any sort of input on any one of the control surfaces, the plane would either bank violently to the right or left. This caused my aircraft to be 100% uncontrollable and caused nose ins in the rice fields (I live in Japan and the farmers here do not appreciate the two foot holes in the ground I am creating from this problem). At first I figured that it was just a CG issue, so as Flitetest suggested, I moved the CG forwards to make the plane slightly nose heavy as "a nose heavy plane flies poorly but a tail heavy plane flies once." Even after adjusting the CG, the plane would still bank violently to the right or left without any input. I asked my teacher what the problem could be, and he said that the receiver I was using (the AR636A Spektrum) wanted to orient the plane upside down from all of the speed and vibration, so I am ordering a normal receiver without AS3X or any correction for that matter. I also did some research on my own and had found nothing at all like my problem. Everybody else using gyros and turbulence correctors seemed to have no problem with their EDFs at all. The scary thing for me was that both planes had the same problem. I purchased a speed build kit of the FT Viggen and when that crashed, I assumed that it was my fault for incorrectly assembling it. But a few months later I purchased a Freewing 70mm F-16 V2 running a 4s setup and still had the same problem. Please help. I'm still a freshman in high school and months of saving my allowance are going down the tubes. Below is a video of my problem that occurs with both the Viggen (shown in video) and my Frewwing F-16 V2 4s. The thing that bugs me most is that the plane rolls and crashes on its own.
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What prop planes have you successfully flown? -
I can fly any type of prop plane. My teacher has taught me how to fly every type of prop plane from warbirds to 3d planes more than proficiently. I tried one of his EDFs and was able to fly that successfully with no problems, but whenever I "fly" one of mine, the same problem persists for both the Viggen and F-16.Originally posted by RCjetdude View PostComment
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What you are describing is not a characteristic of EDF's or any plane for that matter and without more information difficult to determine. The only common factor to both scenarios is really you but not knowing you we could only speculate what caused the crashes. Did you set both planes up and did anyone else do a pre-flight check on them before the maidens? Did you set the CG's per the instructions or just guess? Was the AR636A receiver you used taken out of another plane? I assume so because the plane you had it in does not come with that receiver yet that receiver is programmed specifically for the plane it came in. You can't just drop it in another plane. Did you verify and I mean check, double check and triple check the directions? Did someone else verify the set up as well? I am not questioning your abilities just trying to get enough information to make a rational educated guess as to what happened.Comment
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I have had a couple of Flitetest Viggens and they are great flying models. They do have a tendency to "waddle" slightly till they get up enough airspeed but that's at VERY low speeds like on launch.
What we see in that video is fairly typical of a gyro with very poor programming for the plane it's in. It either has the wrong orientation, wrong gains, wrong wing type or wrong "priorities". Also, if it came out of another plane, there may be programming that is hidden deep in the circuitry that the end user CANNOT access and change.
The use of an unknown AR636A (either from another plane or one that has not been programmed correctly for a particular plane) is THE worst Rx to use in any plane, especially an EDF as there are certain characteristics of an EDF that can really interfere with a poorly set-up AR636A. I also would mimic RCjetdude's question about where the AR636A came from. The AR636A is NOT a Rx you can just drop into any plane and fly.Comment
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Everything was setup per the manual and spread sheet and I checked to make sure everything was running smooth. On the ground both planes were functioning just fine for a few days (it was raining and I had nothing better to do so I taxied it around the room). I am speculating that the receivers are what caused the crash. My teacher gave me the receivers and he had previously told me that he had set them up for gliders so that might actually be the problem. I can fly rc planes, it's just the programming of receivers that I am new to, so I will order a fresh receiver without any auto correction what so ever to see if it was just the receiver. Thank you.Originally posted by RCjetdude View PostComment
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Thank you for the advice on the receiver. I first thought that I had incorrectly put the Viggen together and that was causing it until the F-16 happened. Earlier on, when I placed an order for a second F-16, I ordered a Spektrum AR610 6ch receiver with no auto correction at all. I was wondering if it would require some programming or if it is even compatible with any aircraft at all. Thank you.Originally posted by xviper2 View PostI have had a couple of Flitetest Viggens and they are great flying models. They do have a tendency to "waddle" slightly till they get up enough airspeed but that's at VERY low speeds like on launch.
What we see in that video is fairly typical of a gyro with very poor programming for the plane it's in. It either has the wrong orientation, wrong gains, wrong wing type or wrong "priorities". Also, if it came out of another plane, there may be programming that is hidden deep in the circuitry that the end user CANNOT access and change.
The use of an unknown AR636A (either from another plane or one that has not been programmed correctly for a particular plane) is THE worst Rx to use in any plane, especially an EDF as there are certain characteristics of an EDF that can really interfere with a poorly set-up AR636A. I also would mimic RCjetdude's question about where the AR636A came from. The AR636A is NOT a Rx you can just drop into any plane and fly.Comment
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You have to set any receiver up in your radio for a given plane beyond binding it. I just have to ask, did you make sure your ailerons were going the right direction? It seems like a given but in a rush even seasoned pilots have gotten it backwards at times. I can see the first scenario being caused by the AR636A but the second plane you said did not have such.Comment
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An AR610 Rx is a standard Rx that works in almost any plane. Final programming is done on the transmitter. You need to acquaint yourself with what each model of receiver will do. A few of the newer Spektrum Rx's have built-in stabilizers and MUST be programmed for each plane. An AR636A that was programmed for another plane (especially a sailplane) CANNOT simply be put into a different plane and be expected to work. For one thing, that sailplane was likely a standard configuration with rudder and elevator and ailerons. Your Viggen is an ELEVON plane. A sailplane is generally a slow moving plane with big control surfaces. Gain settings for a sailplane will generally NOT work for a faster plane no matter if it's a prop or EDF.Originally posted by J450N_9H0 View PostComment
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An after thought ........................
Let me hazard to guess ..................... That AR636A came out of a Radian XL, didn't it? I have had 2 Radian XLs and I have also used the Rx's out of them that have been given to me by friends. Those Rx's MUST be reprogrammed for all other planes. If you don't want to use the stabilizer in that Rx, you can turn it into a standard Rx with no stabilization by setting all gains and priorities to ZERO and wing type to normal. You will still have to set other parameters in your transmitter just like if you used any other receiver. IE, set Tx for Elevon for your Viggen and make sure all channels are in the correct position of "normal" or "reversed".
If you have the smartphone APP and the program cable, then there is no need to buy an AR610.Comment
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In that video, I also see an abrupt increase in throttle after the toss, which will cause a torque effect, much like a warbird. Perhaps try a smoother application of throttle, so the flight surfaces can control that torque-induce rotation better.
The second launch, however, appears to be a full throttle launch, so, if the stabilizer is in the plane, it may be reacting poorly to the torque.Comment
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From what I see the plane fly's ok for a few seconds and then goes haywire. Torque effect usually happens right after the toss, not seconds later. It doesn't look like torque effect to me, but some kind of electronic failure that takes place seconds after the toss. I have one plane that has done this 3 times now, and after each repair. I'm replacing the ESC, thinking it might be electrical failure to the receiver. DocComment
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I'm going to check the rates and such on my Viggen and throw in a basic 4ch receiver and see if that does just fine. I'll have a video posted on here as soon as I can. Thank you for all of the help.Comment
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Usually, but if the throttle is slammed after the toss, when the model is barely flying, there is a big increase in torque. The second toss kind of shows that the instability occurs above a certain speed, though. To me, that signals a control problem, which could be as simple as a surface starting to flap because a hinge or control has too much free movement. Or even a servo cable with weak contact springs.Originally posted by doctormike View Post
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I watched your video again but this time, I tried to do freeze frame when you were doing your stick check. It's a bit hard to tell since you did it very quickly, but I think your stick movements did not coincide with how the control surfaces responded. I detected that UP/DOWN was correct but left/right was not quite right. You might want to check that again to be sure.Comment
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Ok, so I tested everything today and toyed around with my radio a little bit and it seems to have worked. I still am not sure what was wrong with the EDFs at first and had a small problem early on when I first attempted to fly the jet, but I have video footage and eventually was able to fly the EDF properly. Sorry for my moms commentary. I told her that this wasn't an unboxing or whatever but more so that people can evaluate what I'm doing wrong and criticize me for it, ha. Hope this video helps to find out what was wrong. Oh, and also, I replaced the AR636A with an AR610, so I don't know if that had something to do with my success. Sorry for the horrible quality of the video, this was shot with an Iphone 4 and a technologically disabled mother, ha.
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Now, that's the way a Viggen should fly. Since you managed to fly it so well with the AR610, I believe you can be fairly sure that it was the AR636A with programming from a sailplane that caused all the problems. Flighttest Viggens need to be launched with full throttle and only after it's had a chance to spool up for a second or two. Otherwise, you can get a bad torque roll or it just doesn't have enough airspeed to fly, which you found out on the first two attempts in this latest video.Comment
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My first posting here. I have a Flitetest Viggen with 70mm EDF that can't be hand launched without running. I measured the thrust and it maxes out on 0.8kg (in stead of the 1.2 kg that was promised when I bought the unir years ago). It may be that the strip AB leds I attached in the outlet are spoiling the airflow too much.
https://youtu.be/hFL4b1_j4lM
(the rattling sound is caused by detaching one motor cable, to prevent the motor from running during test)
Anyway, is the 0.8 indeed too little for a static hand launch? The plane weighs 1.375kg with a 4S 4000mAh battery. If so, I should consider a bungee launch. Replacing the EDF is not an option, it would ruin a big part of the plane.Comment
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The flying weight of this Viggen is stated as being around 0.9 kg (that's with a typical battery - 3000mah, 4s). If you plane didn't weigh as much as you say it does and if your EDF put out what it's supposed to, it should be able to take off with an underhand toss at about a 25 degree up angle to the horizon and a small amount of UP elevator when launching (you can run a mix where you can have about 3 to 4 degrees of UP elevator on the gear switch). You say you can get it flying if you run and then throw it. That tells me you "should" be able to launch it without running if you have the correct conditions - those being a properly calibrated throttle and a bit of UP elevator dialed in for the launch.
Have you calibrated the throttle on the ESC? It may not know where zero throttle and 100% throttle is. This plane should have almost as much thrust as the plane weighs in order to easily hand launch. Make sure the throttle is calibrated and try making the plane much lighter by using a small 4s battery just to see if it will take off any better (assuming you can balance it with the smaller battery). Don't fly it for long with the small battery. If it does, that should tell you that your plane is too heavy for the amount of thrust you're getting.
The video from my earlier post was with a less than full throttle launch and you can see that it still was able to take off with an underhand static hand launch. The following is with a full throttle launch and you can see that it has more than enough power to get up and go.
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Thanks, I'll try your suggestions.
Btw, can you pinpoint the correct cg?Comment
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