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HelicopterFlybarless Rotor Head SystemsOther › FBL Units and NItro Heli's
11-28-2011 03:38 PM  5 years agoPost 1
Supertoyz

rrApprentice

Colchester, VT

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I need some advice on FBL units and Nitro heli's. I own the following FBL Heli's

- Trex 450 V2 3GX
- Trex 500 ESP BeastX
- Fusion 50 Helicommand HC3SX
- Raptor 90 Helicommand HC3Extreme (deceased)
- Velocity 50 N2 (Pending)

I had to send the HC3SX back for an update this summer and bought a HC3Extreme to cover for the time it was away, the Fusion flew very well with either unit installed. When the SX unit came back from being updated I reinstalled it in the Fusion and updated an old Raptor 70 to FBL with the now unused HC3Extreme unit. I installed an RJX FBL head and a new OS 90 engine. The 90 was installed about a week prior to the FBL conversion so I'd flown about a gallon through it and was just getting the tuning dialed in when I converted it to FBL. On the bench everything worked as it should. I took off into a hover and everything was fine, flew some circuits and everything still was fine. Temps got up to about 230 on the telemetry so I landed and richened it a few clicks. I took off and hovered for a few seconds to monitor the temp. After a few seconds of hovering the heli drifted left increasing its roll rate until it struck the ground and beat itself into oblivian. This only took a matter of seconds since it was at a waist high hover when it happened. I have no idea what happened. Since I have several FBL heli's but this was my first FBL nitro my suspicion is that it's somehow related to high vibes. Is this how FBL units act in a high vibes scenario? I'm waiting for a new Velocity 50 N2 to replace the Raptor and I'm very reluctant to install this FBL unit. Without some type of vibration meter (VBar / Skookum) how would you ever have any advance warning of a problem? I had no visual indication of any abnormal vibes, vertical stab, boom supports, skids all looked normal. Because I'm a little OCD I'd like to keep both Helicommand units on both of the Outrage machines so they match however I'm considering putting the BeastX on the Nitro since I hear they are tolerant of almost anything and the Helicommand on the Trex 500. I'm looking for idea's as to what happened and why as well as suggestions.

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11-28-2011 04:28 PM  5 years agoPost 2
unclejane

rrElite Veteran

santa fe, NM, USA

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I don't know about FBL units, but in all the years I've flown nitro the only gyro I've ever used that doesn't give problems in the high vibe environment of nitro is my GY 701. And that's mainly because you can hard mount it without damaging the sensor (supposedly - mine hasn't given trouble yet at least).

My finding has been that the problem isn't with the gyros themselves, it's when you have to mount them on shock absorbing pads. This allows them to wobble about on the pads and that's what gives them fits, causes drift, kicking, etc.

Hard mounting eliminates that, but then you have the problem of if the sensor or unit can take the vibration long term....

That's probably the main reason I'm going to stay FB on my nitro (either that or use the CGY 750 which is also made to be hard mounted)....

LS

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11-28-2011 04:44 PM  5 years agoPost 3
F1 Rocket

rrKey Veteran

Melbourne, Florida ​USA

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The HC3-X series are pretty good with respect to vibes. We use them on 600/700 nitros and gassers without problems. We also use and recommend the thin HC mounting tape for the nitros and gassers. Check to make sure there is not something else with the machine that caused this. If you want you can send the HC to me and I'd be happy to install it and make sure it's OK.

Danny
Esprit Model

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11-28-2011 04:56 PM  5 years agoPost 4
Supertoyz

rrApprentice

Colchester, VT

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Thanks Danny,

I'd used the recommended thicker pad for nitro since I'd already used the included thin pad when it was installed on the Fusion. It was hard to rule out mechanical issues since not much was left of the heli. It's since been dis-assembled and parted out so no going back now. When I looked over the head everything looked intact. The links were either still attached or broken indicating they hadn't fallen off prior to the incident. I emailed Joachim right after the incident and he seemed to indicate that it was likely high vibes but didn't elaborate. It left me wondering if it was high vibes then how would I have known and what could I have done about it? I think the FBL unit itself is fine since I'd used it in the Fusion previously. Although that doesn't mean something didn't fail causing the accident or wasn't damaged in the accident so maybe I will send it to you. I can't recall where I had the gain set, on the Fusion it's at 90. I think I used the base 50 as a starting point but if I had used 90 by mistake could too high a gain in a nitro environment cause an unintended roll? What makes me especially nervous is if it was high vibes as Joachim suggested then how could you ever install it into a new heli where you need to go through break in and tuning as high vibes would be possible until it gets dialed in.

I also ordered replacement thick pads, should I be using the thin even though the instructions say thick for nitro?

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11-28-2011 05:18 PM  5 years agoPost 5
Supertoyz

rrApprentice

Colchester, VT

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I was able to dig up Joachim's response (From Helicommand):

" Regarding the HC3-Xtreme, this sounds a bit like a typical vibration issue. And as you talk about "high vibrations", you seem to have them on your heli?! Aileron inputs are typical for fbl system (all of them) when vibrations are too high. "

Regards,
Joachim

Which left me wondering how would I have known about the issue prior to the crash and how can I avoid the same thing happening again?

With the Raptor it wasn't so bad since it gave me an excuse to buy something new however I'd hate to have the same thing happen while maidening the new heli. It was the worst crash I'd ever had, hard to believe so much damage from only 2' off the ground. By the time I realized what was happening and hit throttle hold not much was left.

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11-28-2011 05:31 PM  5 years agoPost 6
Santiago P

rrProfessor

South West, Ohio

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After a few seconds of hovering the heli drifted left increasing its roll rate until it struck the ground and beat itself into oblivian. This only took a matter of seconds since it was at a waist high hover when it happened
Identical incident happened to me with a BeastX.

it was vibration induced

I was using the stock foam tape on my nitro.
Switched to thin molding 3M tape with a strap and the problem is gone.

Santiago

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11-28-2011 06:01 PM  5 years agoPost 7
GC1

rrNovice

Manchester, UK

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Vibes on my Trex 500 caused my Beastx to veer wildly to one side. I changed some bearings and it's sorted. So yes I guess vibes can cause this type of issue.

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11-29-2011 01:16 AM  5 years agoPost 8
McKrackin

rrProfessor

Lucasville,Ohio

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There are nitro helis with 3G,3GX,BeastX,V Bar,SK720,SK360 and even a few with Walkera FBL......

Did I leave out the HC3 series?

You have to get your stuff straight or it won't work.

Look up any nitro FBL combo you want to on Youtube....There will be a bunch of crazy 3D success stories.

Look your stuff over very closely.

Any FBL system will malfunction in a high vibration situation.

It's more likely that you have a mechanical issue than a bad FBL unit.

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11-29-2011 01:45 AM  5 years agoPost 9
Supertoyz

rrApprentice

Colchester, VT

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I didn't think it was an issue with the FBL unit, it appears to have been vibes but my point is that prior to the crash nothing was obvious. The heli looked, acted and flew fine up until the crash. With no indication of a problem how would you know you had one prior to disaster? This summer my Fusion 50 had a bad vibration, it was weird because it always flew fine and had never crashed, not so much as a tipover. One day it had a vibration so bad that the boom supports were creating a double image and actually humming. I replaced the tail gears, torque tube, bearings and TR output shaft which solved the problem. Point of the story is it was vibrating very badly and didn't have any issues with the FBL unit. So if a nitro gives no indication of any issues then how would you know? I've never seen what the Vbar and Skookum offer, some sort of vibe sensor? I think a vibe sensor would be awesome. It would give you a baseline value that you could use to guage how smoothly your heli is running and would let you know after a rebuild if everything was back to normal, better or worse. It would also let you know how changes in parts such as blades, motors, tuning etc effect the overall balance.

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11-29-2011 02:48 AM  5 years agoPost 10
Manny1776

rrVeteran

Melbourne, Florida.​USA

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Hi have to send back my HC3-Xtreme in the summer too....I have to said the service was perfect they really support me to fixed...I have HC3-Base on my 450Pro FBL as well on my 600proE FBL....no problem at all... the Xtreme is on my 700E FBL an also in fact same some couple of crash with the recovery function.... I love it!!! In my knowledge they will be works at the same on Nitro systems...

Manny

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11-29-2011 07:07 PM  5 years agoPost 11
Santiago P

rrProfessor

South West, Ohio

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This summer my Fusion 50 had a bad vibration, it was weird because it always flew fine and had never crashed, not so much as a tipover. One day it had a vibration so bad that the boom supports were creating a double image and actually humming.
Visible, low frequency vibrations does not seen to be an issue for the FBL unit (but still horrible for the mechanics). Higher frequency like comming from the engine do.

This is why you could see vibes on the 50 and the unit did not acted up on them. Having said that, you must have a something not true around your engine, OR the engine is running very rough due to overcompression, bad mixture, etc.

When I had my incident and decided to change the engine, even though all I did on the tipover was crack the blades and broke a canopy stand off. I found the starting shaft was 7 thousands off!!! That would have shaken the crap out of anything.

Like McKrackin said, it is most likely that you have a mechanical issue, not a FBL unit one.

If you do not have anything out of wack, then it is just that your helicopter frames happen to exite a natural frequency (and they all do) that matches the resonance of the FBL sensor. If you just change the dampening characteristics of the unit's mounting pad you will be off the harmonic and the problem wil be solved.
For me the fix was stiffer tape.

have you seen this:

Watch at YouTube

Santiago

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