Suicidal Trex 500....

[GtD]

what a fun year I'm having ....

anyway...put a new tail pitch slider on and had given my trex 500 a checking over and went through the BeastX setup again to check all was OK then took it into the garden to test hover.

Took off in normal mode...hovered a bit and tried some gentle sudden blips on the throttle/pitch, and even though they were very small 'blips' the tail was moving out several inches.

so, landed and thought maybe head speed was a bit low compared to the normal IU I fly in (about 95%) so landed, switched to IU, mid stick then TH off and it starts to spool up. Just about as it gets to full speed and while I was watching out for tail vibrations before liftoff it suddenly decides to tip over to the right (tail facing me), and having gouged a nice groove through in my lawn it proceeded to rip the blades to shreds, knacker the main gear, tail blades and boom. (oh yeah...brand new feathering and main shaft in their for this test - so they lasted a long time!).

anyway - rather disheartened as I haven't been able to get my heli flying right since I put my BeastX on earlier this year!

It hasn't done this before but has always had issues with the tail never holding despite trying all sorts of gyro gain values.

any ideas as to what could cause this? could it be a weird fault with the BeastX? should I send it back for them to check over?

suggestions on a postcard to the usual address!

maybe what I really need is someone who knows what they are doing

cheers

J

[Si_B]

What pad are you running on your Beast X, and where do you have it mounted (a picture would be good).

[GtD]

it is mounted using the supplied white foam type pad on the gyro tray that is effectively the top of the tail boom block....which is where I've always had it (and the gyros I previously had were mounted there).

btw - should add I am 100% sure it wasn't me putting in an accidental aileron input as I'm super careful and know not to even touch the cyclic controls while still on the ground with FBL.

[Si_B]

I very rarely wait until I have full head speed before lifting off, the quicker you get off the floor the better. I had my Beast X mounted in the same place on my old 500, so don't think that's your problem unless you have excessive vibes coming off the umbrella gears.

Why are you switching to IU before taking off ? The tail not holding when you blip the throttle could be lack of gain, but if you ahve not changed any of the settings, I guess that's not an issue. I think mine was around f or g on the gain for HH.

[GtD]

well, I normally just start up in IU these days (had a close call a while ago where I forgot to switch to IU after takeoff then did a flip...a bit scarey when the headspeed drops like that ).

so I just have TH on, mid stick, IU then TH off and soft start it up to usually near full speed then lift off pretty quickly.

still...I can't think why it should make such a dip to the right without any input....it's not as if I could have any of the settings wrong as I had only just had it up in a hover and was moving it around as normal.

bummer

oh yeah - 1 bit of good news is I had on the 'old' torsion blades while I was trying to get the setup right so at least it didn't trash my nice Edge FBL ones!

[Ross Northcott]

i had a bad main shaft bearing on my 500 last month, in normal it was fine, in ilde 1 at 70% it would drift to the right and at 90% would tip completely to right if i let it, have you chacked the bearings?

[GtD]

well, the upper main bearing is certainly broken now, but I'm fairly sure it was OK just before - I put them in new at the start of the year I think and they've not had many flights on them. Only thing I'm worried about is I replace all the bits & bobs (including main blades - not sure I want to risk the Edge ones on it yet...might need to find some slightly cheaper to test fly with!) and then it all goes pete tong again on me!

I might contact BeastX to see if they have anything to suggest...I think if they are able to check it over I'd feel happier to let them give it the all clear before risking anything like that again.

oh - I had also double checked all connections were fine too so I know it wasn't anything like that (I know what a lose servo connector does...just after I got the BeastX I was using 9650's which needed a servo extension cable to reach...and one of them must have come lose....that really hit the ground...hehe).

thanks for the suggestions so far though guys!

J

[asomaro]

J,

Feel for you bud.

I had similar issues earlier this year when upgrading my beastx from v1 to v2 on both my 500 and 550. It turned out that it was the mounting pad. I changed to the thin green maplins double sided tape and everything was fine and still is on v3.

I'd suggest trying a different pad (thinner), but try spooling up without the main blades and see what happens with the swash at about 50% throttle. If all looks OK then you should be ready to go for it. If the swash still shows a tendency to tip to one side then double check that the servo cables are not damaged (had a problem a while ago where the cable was just a bit worn and it was shorting on the carbon frame but only when it was drawing plenty of amps).

Good luck with sorting it out mate.

Cheers,

[tourerjim]

Boom!!! high frequency vibration" I've spent some weeks trying to find the cause to heli pulling to the right aile.
Only when I converted to belt drive did it solve the problem, first it done it with beastx then try it with 3GX then converted her back to flybar & she was fine, I replaced every bearing, front & rear TT gears you might as well say I completely rebuilt her & as I mentioned the only way to solve my problem was to convert to belt drive, the problem as I've just found out today after do test on the TT at work is when you spin the TT with front & rear gear boxes assembled is a high frequency vibration that comes in at high speed, I then done the same without the gear boxes on each end & still high frequency vibration & this is with new bearing only couple weeks old, I've have now picked new bearing today to do another test tomorrow, but when I think about it theirs been many posts with issue on the 500 tails even from the first TT 500's & remembering having issues myself trying various tail servo & tail nodding.

[GtD]

oh man...you aren't suggesting I have to buy a belt drive now...! - there was me thinking the TT was an upgrade ! (I bought this 2nd hand already with TT btw so yes...I'd have to buy all the belt drive stuff).

I do wonder if that might be it though as I've never been happy with the BeastX - particularly the tail - and it isn't that it can't keep up with me as I'm only just a 'sports' flyer so should easily be able to cope with what I'm trying to do!

I wonder if a 2nd bearing on the TT shaft would help? (i.e. another one like the one that goes in the rubber surround slightly off centre?)

Do let me know how your test goes with the new bearings.

J

[psychosaffa]

oh gosh, hope i dont have your issues!!
just got the settings sorted for the 500 esp with beast x, will be pretty gutted if it dosent go smooooothly!!

[tourerjim]

oh man...you aren't suggesting I have to buy a belt drive now...! - there was me thinking the TT was an upgrade ! (I bought this 2nd hand already with TT btw so yes...I'd have to buy all the belt drive stuff).

I do wonder if that might be it though as I've never been happy with the BeastX - particularly the tail - and it isn't that it can't keep up with me as I'm only just a 'sports' flyer so should easily be able to cope with what I'm trying to do!

I wonder if a 2nd bearing on the TT shaft would help? (i.e. another one like the one that goes in the rubber surround slightly off centre?)

Do let me know how your test goes with the new bearings.

J

I've already tried 2nd bearings on the TT but didn't solve it, the high frequency vibration comes in at throttle 85% to 95% & that's even with new TT, boom bearings & gears, my 500 has the 3GX I must admit she's pulling of some awesome 3D with the belt drive without the slightest twitch, feel reluctant to want to leave belt drive on which is the reason for trying to solve the problem with the TT" but at the end of the day if when I've solved the TT & it doesn't perform as good as the belt then the belt will stay!.

[tourerjim]

oh gosh, hope i dont have your issues!!
just got the settings sorted for the 500 esp with beast x, will be pretty gutted if it dosent go smooooothly!!

The other thing I meant to mention the higher the lipo pack the more noticeable it will be, but if your concerned set throttle to 80% & increase bit at a time being careful into hover

[GtD]

<snip> I changed to the thin green maplins double sided tape and everything was fine and still is on v3.

Is it one of these you are using? Double Sided Foam Tape : Double Sided Tape : Maplin if so...which one?

[danch]

You want the 25 x 10, that's the one I have used

Regards

Dan