Ok two planes taxi out to strip plane1: .60 size cap 232 Radio DX7 digital servos DS821 except for throtle small HXT900 9 gram servo. Plane 2 .40 size Sukhoi Radio JR XF631 servos JR 537
I taxied P1 to the end of strip and turned ready for take off aprox 120 m away. P2 stalled at the edge of the strip so I put the radio ( DX7 for p1 ) on the gound with the aerial facing away from P1 at the end of the stip . Note the plane was at idle. I then proceeded to help the pilot to restart P2. Some time passed aprox 1min when I heard P1 throlte up to full noise, by the time I grabbed the radio we both turned and had to jump out of the on coming P1 at full speed. It collected P2 on the ground with P1's prop working its way down the fuse of P2.......... The Plane is baddly damaged see photos. P1 received damage to the leading edge of wing.
No body touched the radio ( DX7), I thought I might of grabed the throtle when picking up the radio and made things worse. We changed the prop on P1 then taxied aprox same distance away, Left it at idle sat the radio on the ground. We folded the aerial touching the ground. We waited about a minute then with out reason the plane throlted up, no thouching anything. We tried the same thing again, this time the aerial straight, so no contact with the ground. Even checked nothing was thouching the bind button on the back of the radio. After a perioid no more than a minute it did tthe same thing .... throlted up.......... Can anyone shed light on this ???????????

thats crazy

Subscribing. I never heard/seen anything like that. I'll ask around to see if anyone else has.

Frank

Very disturbing. I'm still on 72mhz but hope to move to 2.4 in the not-to-distant future. Hope they get all the bugs out by the time I do.

To me, it sounds like the spektrum receiver went into fail safe for some reason. Problem is, it sounds like the fail safe position was full throttle rather than idle. Was it bound with the throttle sick forward or was the throttle maybe reversed after binding? That happened to me on an electric when I accidentally turned the transmitter off. If that's the case though, why did it lose signal and go into fail safe? Maybe the antenna being so close to the ground is an issue?

Any chance your radio battery was low? Or your battery has a loose connection? If you turn off the DX7 while the plane is still on it can do the same thing. Just trying to rule this out.

that's wild. it proves these new systems are not 100% yet. i remember a simular incident many years ago when the first PCM'S came out. a guy had just landed his plane.he got distracted and without thinking he turned off his radio while the motor was still running. the failsafe on the throttle was in reverse and the engine went to full speed and the plane went thru the pits taking out another model then hitting a parked car. close call!. mostly pilot error.
glad no one was hurt in your incident.

Another question for you.

I'll go with ChuckW and Muroc1, there's a lot
of factors involved. Me, i'm thinking low battery
and fail safe settings ? JMO.

Bob

are you replying to me or basman

Ya know, just in hind sight, in order to make any failsafe work, it has to be verified, but that's the sad thing, if I tell the TX point x is low throttle and point z is high throttle, why the he*& do I have to tell the program which way to failsafe to? Pure garbage, I'm going to get flamed for saying this but it's true. Plus, why the fu*^ is your 2.4 system going into failsafe at ranges that a 72 MHZ TX can do with the antenna down, maybe we all should start to think of these new radios as guns, treat them like they're loaded all the time, never let the assumption that technology will save or protect anything. I still fly 72 MHZ because of 2 reasons and I'm not alone, A) I don't trust anything that cycles through the frequency on a non-stop basis & B) It's too damn exspensive to outfit my whole fleet of 16 aircraft with receivers.

And another suggestion. Looks like it's leading to a loss of signal and a incorrect fail safe setting.

I'm inclined to agree with most everyone else. It sounds like the failsafe kicked in and maybe it was setup incorrectly. It's horrible that it happened and great that no one was hurt, but I just have one question, and please don't take this the wrong way because I'm not trying to pick on you, but why would you leave a plane on the runway with the engine running and lay the control on the ground and leave it?

You hit that one Planebuilder.. I'm the only one out of 5 or 6 guys in our club that DON'T have a 2.4 that flys regularly. There has been a couple of lost planes because of " I don't know what happened!" Everyone of them was with 2.4 TX. I won't be buying one in the near or far future !! And the last thing you said, at close to 100 bucks a plane the RX are just too expensive. I try to keep 6 planes ready to fly. With everbody going to the new TX, the "old stuff is dirt cheap"!!! This hobby is supposed to be fun ! Not break the bank.

I suppose if I did go to 2.4 I would get the Airtronics rds8000, it's way cheaper than any of the others and I've learned from RC KEN that it will only reboot when the voltage gets down to 1.8 volts, so pretty much the servos will stop moving before the receiver goes into failsafe for low voltage. But what manufactures need to do is have a real time reporting of RX battery voltage on your TX, if we can make these thing hop frequencies, why can't we make them tell us critical details to the transmitter, like receiver input voltage? Ya listening manufactures?!

Ok guys fail safe is midstick and no throttle, and should I have a plane Idlleing on strip maybe not but we tried this three times and had the same result????? I love the spectrum system and still swear by it but is this a problem that has gone unoticed? Maybe ground effect? The other thing is second flight of the morning both radio and plane batt checked out fine. I even had three more flights with plane one the cap.....

Tried that that the throttle once radio went off went to full open ...........so first mistry wrong fail safe , but still remains why loss of signal at no more than 120m and if was coming towards us why not regain contol once picked the radio ?

I had something similar happen. New model, on its 4th flight with an AR500 receiver and an X9303. I had it idling in the pits. I looked away for a second, and the next thing I know the engine has revved up and the plane is in the air. Fun moment! The throttle stick was at idle, the battery was new and freshly charged, and the radio was in my hand. It's a brand new engine that was being well-behaved after a quirky break-in period.

Like I said, you programed the radio for end point and direction of travel, so with that said, why do we have to tell it twice which way to go when it looses signal, kinda stupid if you ask me. Say you had to reverse the throw because the throttle was backwards, well, that tells the TX that the idle is at the bottom and WOT is at the top, it just gives a reverse signal to the servo, if this part of the program in the TX doesn't copy over into the failsafe setup then JR and Spectrum has major safety issues with their programming. Youo shouldn't have to tell it twice which way to go weather it gets signal or not. But as far as the ground effect issue, the plane is at the same altitude as the TX, and if it can't tell the RX to keep idling at 120 meters away, repeatilly, then the next stop for the TX is the manufacture or the trash can.
I really think you ment 120 feet, because I'm just drooling over the thought of a 360' runway, and that's if your standing at the very end.

I've seen this same thing happen. Nathan King (RCU user name = NathanKing) was practicing with his 2M Icepoint airframe with O.S. Max 1.60 FX and Spektrum DX6i radio system just prior to our club's pattern meet last August.

He had a lot of problems with the radio installation despite meticulously testing and range checking his receiver and battery setup before flying. Nathan has literally been diagnosed with OCD, and his entire installation was way beyond a "by the book" setup, including a 2800MaH 6.0v NiMH receiver battery.

Nathan was still getting lock-outs with his pattern plane that were resulting in loss of control for several seconds at a time. He was extremely fortunate that they all occurred while either flying uplines or flying straight and level. After what turned out to be his last Spektrum controlled flight, Nathan recovered control after yet another lockout and quickly landed his plane.

Because of his haste, Nathan simply put the plane down as safely and quickly as possible down at the north end of our runway; it landed with the engine still running. Nathan was also working on fitting his tuned pipe setup, which wasn't quite perfect yet, and he couldn't shut the engine off from the radio. He had to block the pipe's exhaust tip to shut the engine off.

As Nathan walked out to the airplane, he left his DX6i transmitter sitting on a wooden starting table within line-of-sight of the idling aircraft. The antenna was perpendicular to the ground and not in any way pointed toward the plane. Just as Nathan got within 20 or 25 feet of his Icepoint, the 1.60 FX slowly started to rev up. Fortunately it was in the grass at the end of the runway and not on pavement. The wheels had just broken loose and the plane had just started rolling when Nathan ran up behind it and grabbed the tail of the aircraft.

I was standing near his radio holding my plane in two hands and nobody else was near it. Nathan looked back to see who had been jacking with his transmitter and realized that nobody had touched it. His beloved Icepoint, his pride and joy, had been about three seconds away from launching itself on a ghost flight over our parking lot and toward the lake.

Nathan went home the day before the pattern contest and yanked out his Spektrum DX6i radio setup and AR6200 receiver. He reinstalled his old Futaba R127DF receiver and reprogrammed his 72Mhz Futaba 6EX transmitter. That's the radio setup he actually flew at the pattern contest.

To this day, I don't know if Nathan has even attempted to fly his Spektrum radio system again.

I'm not too happy with the Spektrum batteries. I had a 3 month old 1100mah pack that had been cycled and showing good, go bad after 15 minutes of flight. I lost a nice plane to a new battery gone bad. What is funny, the voltage showed good but then right after the crash it showed only 4.3 volts. My plane too, went from low idle to full bore, before crashing. I have tried to cycle the battery now and get only 34ma discharge yet it will show 5.4 volts on the meter. I still used JR 7202 and have no problems with JR but I don't think Spektrum is the same. I know of two other pilots who have had the same type of failures with Spektrum batteries. Try for the heck of it, another on board battery. It can't hurt. Do the same test with the new battery. You might have a cell failing or something.

there are a couple guys in our flying group who i consider expert modelers and builders. they build trophy class planes,gas,glow and electrics. one is a retired electrical engineer. they both refuse to use 2.4. . they tell me they do not trust the systems as of yet and stick to 72.mhz. we have had some incidents with 2.4 systems failing and the failsafe was the suspect. and talk about older stuff being cheap. a local hobbytown store had some left over older futaba 72 mhz fm dual conversion 7 channel receivers new in the box for $20.00 a piece. a store employee told me 2.4 has taken over and they were clearing out all 72mhz radio equipment.

21 posts and you guys have missed the fundamental mistake of this whole ordeal ...

Never EVER put down the radio of a plane with a running engine that is not physically restrained. I don't care what kind of system it is with what failsafes. This is asking for disaster.

Bedford

Here's an old story, a long time ago when 2.4 came out for cordless home phones they sucked, when me and my buddy use to call eachother to figure out where to meet up on our dirtbikes and where to ride we got a lot of static and poor range. You just couldn't talk about going riding in ileagal areas infront of your parents ya know! So we unscrewed the standard antenna and installed a R/C antenna from our R/C car TX's, yes the old 2.4 cordless phones came with screw in collapsable antennas. Well, as we were B.S.ing about where to ride and what to do, he walked out tward his parents shed and I overheard his neighbor talking on the phone, when he identified who it was, it was his girlfriends mother talking about how she didn't like her hanging around with him. The funny thing is, they lived 1/2 mile away. Go figure, safe, secure 2.4 isn't so. I think most of the problems with 2.4 are due to poor R&D or programing on the manufactures side. But everytime I log on to RCU, it seems like someone has an incident with the 2.4 systems that is unexplainable, just doesn't give me a warm and fuzzy feeling about putting it in one of my hand built planes that took me 1/2 a year to cut and assemble just to watch it take off on it's own with no control.
The other thing that boggles me is how do you range check a 2.4 system? They come with a rubber ducky antenna, right? In the 72MHZ world, you walk 33 paces, aprox 100 feet, away from the model with the antenna down, if you still have control of the aircraft with no gitters, then the range check is complete and satisfactory, how do you do it with a 2.4? can't collopse the rubber ducky now can you, just hope for the best and take off, or do we wait idling to see it it takes off on it's own?

no 100m to 120m we fly on a turf farm