What happened to the trex 700 tail hum?

[ualdrivr]

Originally Posted by -kenny-

I'm looking at buying a new heli and the new trex 700L top looks attractive to me. But i was wondering if there still is an issue with the tail humming and shaft snapping.

Tail hum? What tail hum? Never had the issue on mine and I have one of the first DFC models, since it was introduces in 2012.

[-kenny-]

You seem to be a lucky guy then :-)

Sent with Tapatalk from my Oneplus One

[paulmedford]

Hey Kenny, if you are considering the agile 7.2, please look at the mikado 700xxtreme, its almost the same , and its a very good heli. You would not regret getting one

[shein95]

I've never had it on mine in the almost 2 years i've had it. will say i did all the "fixes" before i even flew it. Went rail blades out the box, extra tt bearing, new tail shaft and today will be the first time i fly it over 2000 head speed. it has been a very reliable heli for me.

[Rotory30]

trex700hv bought last year in november, all stock added 2nd bearing to torq tube and tail boom brace supports when heli was build, over 150 flight to date, lots of tic tocs and piro maneuvers and flips, never lubed the tail and main gears, never had a gear strip and no issues, no tail humm and running 2200 head speed, very solid flying heli.

i would reccomend doing esc fan mod if using 120cc speed controller.

[rhodesengr]

Originally Posted by Rotory30

i would reccomend doing esc fan mod if using 120cc speed controller.

Is that a product that Castle sells or a DIY sort of thing

[paulmedford]

Castle sells a fan for the edge series

[escsniper]

I know I am here, but I wanted to weigh in on my tail hum issue. I recently bought a 700 kit with the all black gears and the new non-step tail shaft. My hum was horrendous. I took the stock tail blades off and discovered they were about the worst out-of-balance set of blades I have ever had -- both mains and tails.

I tried slapping on a pair of plastic KBDD blades on to see if that solved the problem, because it was the only set of tails I had at the moment. No hum. I have since put Rail blades on and still no hum.

So, I guess mine was caused by a poorly matched set of tails. That's not to say someone else might have had a different cause...

Oh, and by the way, I must also say that I am impressed with the rest of my kit. Always have been a fan of Align helis, always will be!

[marc8090]

Interesting findings.

[utrinque]

I fly three 700 clones, two of them stretched to 800. My friend is flying one stretched to 800. We use clone tail parts mixed with some Align parts. I have Align slider he has Align tail.gripps and tail umbrella gears but clone slider.

We did not experience any tail hum since January.

Benji just got second clone kit. I have four of them in total.

I use cheap $4 CF tail blades and did not have any problems with them either.

Benji is pushing his 800 harder then me. Just look:

Turnigy TGY BLS 805 tail servo test - Assault 800 by benji (5 min 10 sec)

[OnTheSnap]

Originally Posted by el guapo

the black helical gears are strong.

I agree with Greg on this. You'll have to trust me when I say that I've stripped hundreds of TT gears in this hobby, and right now the Align 700 gears are at the top in strength. I've owned 9 different types of 700's, and among the TT stripped gears on all of them. I have a good Idea where the limits are on each.

On the 700e as with all TT if you allow it to wag violently it can damage gears. You need to be cautious with gains on all TT.

For me I also do a lot of high energy maneuvers that can over speed north of 3200 rpm. In these cases if I have the gain too high on any TT heli, gears vaporize.

If you decide to go with the 700l, you'll have one of the toughest helis out there proven over time with constant improvements making it one of the toughest models in the business.

FYI - just sold my Agile 7.2. kept the 700e. Long story.

As Greg said, rails or zeal replacing stock fixed my tail hum. In my case the tail grips wore notches in the root out the tail blades. So when tight they still had slop and felt loose when centered. Adding the Align shims or going with tail blades with a bigger root fixed the issue for me.

[rcflyerheli]

Originally Posted by OnTheSnap

As Greg said, rails or zeal replacing stock fixed my tail hum.

Have you run the Zeals. I just put a new Logo 690 in the air and tried them, but had horrible vibrations. They are over two grams heavier than the Rails. I did nothing but switch to a set of the Rails, and the vibration log issues went away.

It seems to me that the change to Rails has been an almost universal fix to tail hum vibration issues.

[OnTheSnap]

Originally Posted by rcflyerheli

Have you run the Zeals. I just put a new Logo 690 in the air and tried them, but had horrible vibrations. They are over two grams heavier than the Rails. I did nothing but switch to a set of the Rails, and the vibration log issues went away.

It seems to me that the change to Rails has been an almost universal fix to tail hum vibration issues.

Running zeal tail on 5 different helis. Sounds like you got a bad set?

I brought this up with them and they are improving the tail blade quality.

[338federal]

I ordered edge tailblades 105 and 115. Rails 115 to so i will test what is best. Maybe 120 or 130mm tail blades for very low rpm.

[rcflyerheli]

I have personally found that the Edges and the Rails are almost no noticeable differences in the air. the only issue is that Edges are no longer being made.

I did find that on my Rails (at least one set) the CF skin must be fairly thin as they will buckle and dimple across the chord of the blade. No split on LE or TE, just wavy between the two. That's the most obvious reason that they are so light.

[Trexwilly]

I am running the Zeal 105s and they did quiet the hum, but it's still there, I have a set of rails, I guess I'll give them a try?

[Inkslinginmofo77]

Rails are great. If u run higher headspeeds 105's are great. Lower HS and 115's are great. I fought with my tail forever and put some rail 116's on and the RC-tek counter weighted blade grips and my tail is super smooth and still as a rock. No bouncing, racketing, humming or wagging. Used all metal servo horn and tail pitch slider. Super great investment.

[rcflyerheli]

I also recently switched over to the Vbar control with the built in vibration analyzer. Of all the helis I have, my 700 DFC (V3) shows the least amount of vibration on the analyzer, and by a good margin.

[Wizza]

Interestingly, Mikado suggest four (4) bearings on the torque tube of the XXtreme700. They also suggest spacing distances/offsets along the torque tube, on page 9 of the manual. Might be worth a try, and see if any difference. If I get a chance, I'll make up a spare torque tube and test it out...

Update - for those interested, Mikado space their bearings at 60mm from end, then another 260mm, then 220mm, then 160mm, leaving that last bearing 100mm from the other end (total equals 800mm length for the 700 XXtreme torque tube).

[338federal]

I have a stretched 700E v2. Only 2 bearings in TT. No hum but not in the places what says in manual.