Did YOU fly today??

[Grumpy]

Bigpops, sorry to hear about the crash, what a nightmare. I fitted the upgraded tail hub to my 700 a few weeks ago after reading about a few similar failures. I had assumed that it was only nitros with their high tail ratio and guys who run screaming headspeeds and do overspeeds that were having the problems, but I upgraded anyway as a precaution.. This is the part should anyone reading be interested: https://www.modelhelicopters.co.uk/a...eavy-duty.html

I got a few flights of my own yesterday, great weather but it was quite windy up here:

[bigpops]

Nice Grumpy. The weather was great, that's for sure. There wasn't a cloud in the sky here.

I never ran crazy head speeds on my Trex 700. I used to fly at 2050rpm until I started flying Cyclone blades, when I dropped it to 1950 about 18 months ago. Only about 50 flights on the model too.

I think I'm looking at about £160 to fix it if I buy a used canopy (excluding blades). I don't know whether to bother or just sell the parts and buy a new (different) heli. All gears and shafts survived and all servos were undamaged. Swash plate bearing is mashed and you can't change it, along with a servo arm, swash links, boom, torque tube, and I need to buy the new hub/grips and tail blades.

Off back to the field this afternoon for some more Logo 600 love. Just a couple of hours today I think.

[Mike Sanders]

I had a great time today at MK which was even sunnier than usual. It was about 23 degrees with almost no wind. Richard V put some cones out and I practiced the hovering parts of the B test. There is room for improvement!.

I saw Mike Wood hovering for the first time ever!

[chrisleematt21]

Bigpops, sorry to hear about the crash, what a nightmare. I fitted the upgraded tail hub to my 700 a few weeks ago after reading about a few similar failures. I had assumed that it was only nitros with their high tail ratio and guys who run screaming headspeeds and do overspeeds that were having the problems, but I upgraded anyway as a precaution.. This is the part should anyone reading be interested: https://www.modelhelicopters.co.uk/a...eavy-duty.html

I got a few flights of my own yesterday, great weather but it was quite windy up here:

Is this the same tail blade holder that is used on the 700xn? Have there been many instances of the blade bolt breaking? I fly a 700L top most days, but never heard of a blade bolt breaking before, a little bit curious.

[hedge]

Is this the same tail blade holder that is used on the 700xn?...

Yes it is, i asked over on freak if there where any other changes to the 700xn tail unit. If its only the blade bolts then I might skip it, was not sure exactly where the "...hexagonal screw upgrade was.." that will bring me "...much fun and free flight"

[chrisleematt21]

Yes it is, i asked over on freak if there where any other changes to the 700xn tail unit. If its only the blade bolts then I might skip it, was not sure exactly where the "...hexagonal screw upgrade was.." that will bring me "...much fun and free flight"

Certainly not the free part!

[p4ddy]

I maybe wrong but isn't a tail blade grip bolt the same issue that the original 700N had??

[bigpops]

There have been a few over the years. The last one before this I remember was the tail shaft that had a step in it from 6mm down to 5mm right at the hub. They were prone to snapping right at the step.
I personally saw one of those break on a brand spanking new 700N DFC. Even though the new part had been released, it wasn't in the owners kit and he'd fitted the old part knowing nothing about the potential problem.

[chrisleematt21]

Not sure if I should change mine or not.
Do you need the links as well?
Align Trex doesn't show them in the picture but
align does show them, and the part number is slightly different

[bigpops]

For what it costs, I would. Yes, you need the plastic links if they don't come with the grips. I also noticed slightly different part numbers as you have from the Align press release.

When the grips were listed, I did consider upgrading. But because I'd seen people hammering on the 700 electrics for years, I thought nothing of flying the old ones with my mild flight style. For all I know those guys could have been changing the bolts every 20 flights, so you never can tell.

[hedge]

There have been a few over the years. The last one before this I remember was the tail shaft that had a step in it from 6mm down to 5mm right at the hub. They were prone to snapping right at the step.
I personally saw one of those break on a brand spanking new 700N DFC. Even though the new part had been released, it wasn't in the owners kit and he'd fitted the old part knowing nothing about the potential problem.

This is the one that's most common, not seen anyone break a tail blade bolt? Is it def the blade bolt that is new? Or is it the bolt holding the thrust race? I asked on HF but no answer yet.

[bigpops]

My apologies. I just noticed what I typed in my post above after reading your post. It's not the blade bolt that broke, it's the bolt that holds the grip onto the hub. Anyway, the old ones (I had) are M3, the new ones are M4. M3 is still common on many 700s that don't have a problem. The Logo 700 and 800 for example, though they use a spindle that has dampers like a head does.

[Grumpy]

Over-tightening the bolts could be part of the problem. It's almost certainly a fatigue failure. If you tighten the screws really hard down it leaves less 'spare capacity' in the material to cope with the cyclic stress that results eventually in fatigue failure... Just a thought?

[bigpops]

There's no way I over tightened them. I know better than that, especially with small bolts like those.

What's more likely that there was some vibration in the tail and eventually one gave up due to fatigue. Though mine, equipped with Rail tail blades, had no audible hum that you hear of when talking Trex 700 tails, nor any warning of raised vibrations in the Vbar log in a hover.

[Grumpy]

Fair enough..
I know i'm probably guilty of over-tightening grip retaining bolts. They are so critical and i REALLY dont want then to come loose so I tend to make sure they are extra tight. These failures have made me re think, in the future I'll just let the Loctite do it's job and do no more than snug the bolts firmly down.