Futaba FASST - lost signal on ground after landing

[JP-4203]

What a weird situation: I was out flying my Freewing T-33 today, take-off as usual, normal flight, then prepared for landing and after touchdown I let my beast roll out on a long concrete runway - maybe 400-500 meters/yards distance from where I stood with my Futaba transmitter. I intended to taxi back giving full right rudder/nose gear steering, but the beast did not react - instead it went full throttle without my giving any such command, by chance it took off again and only then I instantly regained command! I was lucky to have enough battery for a 180 degrees turn and safely landed again. Now what happened? There is only one explanation: for whatever reason, my Futaba R617FS receiver lost signal to my T10CG transmitter when the plane was rolling quite far down the runway and by failsafe default settings the throttle was activated. After lucky take-off, the receiver immediately regained transmitter signal and I had full control again.

=> Why would the receiver lose signal on ground? Was it my body physically covering/shading the signal when I kept the transmitter position towards the beginning of the runway with the plane being at the end (just turned my head towards the plane to assure smooth rolling out, normally very concentrated and indeed did not turn my full body towards the end of the runway)?... really bizarr no signal issues before and the R617FS is equipped with two antennas! Anyone has any similar experience / advice to share for "far distant ground handling"?...

Thus far my lessons learned: 1) throttle failsafe position to zero 2) turn body/transmitter inline with the plane on ground 3) envisage short landing/avoid never-ending rolling-out 4) irrespective of 35 years RC model aircraft experience, always be prepared for the unexpected!!

As you can see, it is a simple concrete runway of some 500 yards length, no obstacles (but me...):

(flew my T-33, not the Venom DH112 pictured below)

[James]

The venom hatch can be tight spacing and the Futaba RX's have long aerials. Can you post a picture of how the RX is mounted?

Could just be that when you landed, at the angle the plane was at to your transmitter your signal could have been completely shielded by the LiPo?

[JP-4203]

The venom hatch can be tight spacing and the Futaba RX's have long aerials. Can you post a picture of how the RX is mounted?

Could just be that when you landed, at the angle the plane was at to your transmitter your signal could have been completely shielded by the LiPo?

Hi James, thx for your thoughts, it seems rather unlikely that both antennas were shielded by the Lipo, one antenna was backward ligned, the other foreward and with the plane rolling away from me, the lipo was positioned at the front not at the back.

BTW, I was flying with my Freewing T-33, sorry for any confusion about the runway pic where i posted the Venom. Find enclosed some pics how the receiver is mounted in the T-33:

thank you and best regards from Switzerland
JP (the one with the Swiss Hawk U-1271 featured against its original in the Air Force Museum you posted last Friday in your live show... 😉 )

[James]

Well, I will say, that having one aerial forward and one backward is NOT the proper way to mount them. You want your aerials to be 90 degrees from each other so that they are offering the full diversity possible acting in 2 planes of existence.

The way you have them is 180, so they are only half as useful. I would keep the one going toward the back as you have it, but then the 2nd one I would aim that down or out toward a wing (sometimes I accomplish this by using a small Phillips and plunging it through a thick part of foam and slipping the aerial in that tunnel created)

We made a video recently about it, but basically make an L with your thumb and index finger, that's how the tips of your aerials should be placed in an aircraft. (just the tips, you can maneuver the wires (without creasing it) as much as you want) but as long as the very tips are as far away and 90 degrees will offer the most success

[JP-4203]

Thanks for your help James, excellent video and will change my antenna tips with a 90 angle!

[James]

Thanks for your help James, excellent video and will change my antenna tips with a 90 angle!

No problem man, glad I could help and happy that your not posting this with a smashed airplane already. After you replace the RX aerial placement, next time you head to the field, taxi your plane around the runway at all angle in the low power, range check mode. Keep moving all the surfaces and see if you can mimic what had happened the first time. if you notice any glitches or delayed responses then something else might be going on, but my money is on the just distance and angle you were at with your aerials as they were was your culprit this time.

[JP-4203]

Not smashed that many airplanes recently, lucky me this time!! And yes will definitively do another range check again in the low power mode!

Even though it looks as if it came into the age, the T-33 flies amazingly well!! (watch it with onboard cams during my maiden a year ago: https://www.youtube.com/watch?v=5rnfbJ5mPSs)

rgds
JP

[James]

Such a solid flyer. Definitely report back when you go back out. That's one of the hardest parts of the hobby, is getting answers to questions you didn't realize you even needed to ask. We can't possibly know what we wouldn't think to ask

and...

[JP-4203]

so true indeed, willdo James😎
JP