Hi all,

I'm looking for some opinions here:

While flying on Saturday, I tripped over something (no plane in the air, just walking backwards while holding my transmitter), and in a fine example of athletic prowess, managed to land flat on my back with my transmitter at my side. My antenna was extended at the time, and was a little crooked, which I was able to straighten (I did order another antenna though, to be on the safe side). It doesn't look like anything else is wrong with the TX, and I did get one more flight in and it seemed to work fine (after range checking on the ground again), but is there anything else I need to worry about? There were no visible signs of damage, or audible noise as if anything is loose...

So, I am looking for opinions (other than that I shouldn't walk backwards, and need to pay attention to where I am going! :-) - is this something I should worry about, or not? Like I said, it seems ok...

Thanks!

Well...

Depends on how hard it hit and what on (grass or concrete or anything in between). You may have no problems, ever, or the next flight might be that planes last. You range checked, good deal, but if the IC board was cracked you may not find out until later. If this is the end of the season for you, I would probably send it in for a checkout. Let them know what happened and the service center can look for problems, if for no other reason than your peace of mind. Otherwise, I guess you just fly and if something happens it happens, if it doesn't, it doesn't.

I agree with Mr. Schwagle. The best insurance is to send it back to the manufacturer for a check up. Cheap insurance. You could also have cracked the transmitter crystal, and this doesn't always show up on the next flight or so. When it does show up, it will be a mysterious loss of an airplane.

Silversurfer

silversurfer hit it on the head, CHANGE THE CRYSAL!!!!, they can be a bear!! to detect somtimes if it is cracked, i was getting glitching for 3 weeks one plane, i checked the crystals and all seemed fine but it did end up being the crystal, by good fortune i didnt loose the plane to it but soooooooo easy to do just that.... for the price of a new set is it worth taking that risk?.......


as for sending it back to the dealer, i have had BAD experiance there, i wont mention the brand but my wife knocked my trany of the table onto the gimble sticks, being the trany to my large spit i didnt want to take the chance i sent it back to the manufacture for a check up, 2 weeks latter i get it back with a note saying all is well NO PROBLEMS but i still had to pay for the check up (normal practice)

at the field i was going throught the usual pre flight (engine running) when my spit decides to thunder down the runway of it own free will, the throtle just opened up full bore on its own, a club member was quick enough to chase it donw the runway LOL dived and managed grab hold of the tail saving my plane...

i decide to check out the trany when i got home together with the rest of the radio gear only to found the curcuit board behind the throtle was cracked in 3 places!!!!!!!!!!....

needless to say the manufacture just left it on the bench and took my money!!!!, not happy at that....

but that was a one off (i hope)

jbeck

I thought You might like to see a photo of the insides of a crystal. This is a very thin quartz wafer with two wires attached. Here is the problem with the crystal. The connection to the crystal cannot be soldered on or glued very good and they sometime come loose. You can see that the connection is a coil of wire and the crystal is just inserter in the coil. Some type of material is applied to the connection to help keep the coil in place, however they sometimes come loose on an impact.

If you have a plug in TX crystal you can test it the same way most mfg test them. From waist high drop the crystal on a linoleum floor. Then reinstall it into the Tx. If the radio still workes your crystal is ok. If the radio does not work then buy a new crystal. If the connection of the crystal is loose the impact of the jar will finish it off. If the connection is not loose the crystal will withstand the impact with the floor.
Always make this simple test to the receiver when you crash an airplane regardless of how mild a crash.

This past summer I crashed a US 60 straight at full throttle from about 200 feet. Totaled the plane broke the receiver case and threw the crystal out of the receiver. When I picked up the plane I did not know the crystal was missing. When I arrived back home and went through everything I noticed the drystal missing. The next day I went back to the crash site and found the crystal about 8 feet from the impact point. Both leads were bent a little. I took the crystal home and straightened the pins and performed the drop test twice to be sure. The radio worked correctly with the crystal installed in a different receiver. I still use that cystal.

Many people will say "I would not use that crystal" and that is ok with me if they would not use it. But let me ask you a question. If you sent your Tx back to the MFG how do you think they would test the it?
You can follow the reactionists reasoning or you can make your own decision.
Note: I am an electronics technicial by education.
Hope this helps
Lee

Thanks for sharing that bit of info Lee. I like your style of reasoning.

We had a club member who dropped his TX and cracked the case. He range checked it and decided he could fly until he could send it in for repair. Apparently he was lucky enough to not mess up the Xtal. He flew it for a couple of weeks with no problems. Just plain lucky. This was an old free flighter and his airplanes were of that type so they mostly flew themselves. He flew in the first Nats that had an RC competition and got second place after Walt Good. He said Good got first because he could turn back and land and my friend could turn but not far enough.

Here's one that you might not think of. I started with a JR 662 and during training it got pulled off of the bench onto the concrete floor by the buddy box cord. Everything looked and worked Ok and I just got a small scratch on the housing. Well about a week later, I was setting trim for the day since we had increased the flying speed that I was getting used to. I trimmed a little down to keep the plane flying pretty level. Did it a couple of times when I became used to the trainer wanting to climb at higher speeds. Well, at the end of one of the flights (actually it became my last for a while) I began to trim the elevator back to a more up position. The trim switch would only work moving the elevator down. My instructor saved the plane by doing tight circles at the end of the runway till he got it down. Found out later from the mfgr that the trim switch for the elevator had slipped out of position when the radio fell to the ground and it would only trim down. If you don't send it in make ABSOLUTELY SURE that you have checked EVERYTHING before assuming no damage was done.

Scalebuff...

I know this has been beat to death, and the arguments are sincere, in the US you aren't supposed to change Transmitter crystals.

Perhaps my understanding is incorrect, but I thought the restriction only applied to changing the crystal to one of a different frequency. If one isn't allowed to change the Tx crystal at all in the USA, why are they available for sale here? Perhaps someone can find the FCC ruling on this?