chadxp1

My Feedback: (2)

Maybe missfire is not the best word to describe my problem but:
Ihave a problem with my new Raptor that I struggling to diagnose. The heli seems to studder or twitch ever so aften as Its flying, high idle, and hovering . At first I thought it was low batteries causing the receiver to loose com with the transmitter but anymore Iwondering if it isn't the engine missfiring as Iruled out the batteries. The symptoms are a mis fire sound coming from the engine and a tail twitch symutanously. With high RPM the problem isreal noticable. Tonight I decided to richen the engine up quite a bit. This seemed to help but did not totally cure the problem. Iwondering if the lower engine RPM caused by richening the engine is disguised the real problem? Is there such thing as a lean condtion missfire? Iwonder if the frequency of the rotor/bearings is messing up communications with the transmitter? (Im using a Futabl FM transmiiter/receiver). Idont think this is a transition thing from low idle to high throttle as I have experimented alot with the mixture screws. The engine runs good other then this which im not totally sure is the engine.

Chad

Gavin2407

Hi Chad

I'm currently running the 53 Redline in both my heli's and had a similar issue with my latest engine. What you describe, it would appear your engine is running to lean. What does the back plate feel like after you land? It should be slightly warm but you should be able to keep your finger on it without it burning you. It could also be a combination of the top ends of your throttle and pitch curves, whereby your pitch is to much or to little for a given throttle setting. I generally start with linear "curves" meaning 0, 50, 100 for both curves in normal mode, then use a taco to get close to 1800 rpm from half throttle to max throttle. Idle up is set at 2000 rpm. As our engines produce max power at 17000 rpm and with a gear ratio of 8.5/1, that leaves us with 2000 rotor rpm to keep engine at max power. If your engine is sounding like it's stuttering before the "mis-fire" then it could be to rich. I'd rather start going richer before going leaner, these engine can't handle a lean run.
Regards, Gavin

chadxp1

My Feedback: (2)

Its not the engine. Something is causing the servos to twitch. I witnessed the engine throttle twitch while in a high rpm idle. Also at adifferent time the heli jumped about 3-4 inches of the ground while in a high rpm idle.The twitch effected the pitch servo that time. This has happened at different locations therefore nothing in the general area is causing this.
Any help? The radio and receiver where pulled from my Hirobo which I did not notice this problem.

Chad

hobby_man

My Feedback: (8)

static charge

Gavin2407

From your subject line and first post I assumed it was your engine. Electronically speaking, there is only a few things it could be and you need to take the time to perform a process of elimination. swop the servos around and see if it still happens on the same channel. if no, then it could be your servo itself. if yes, then it could be the reciever. Agree with Hobbyman that it could be static. You gave alot of engine info but only that your using Futaba FM Tx/Rx. Give more info on electrical setup. Batteries, gyro setup, servos, reciever and switch or anything else you have installed, as they could be clashing or not installed/setup correctly.

chadxp1

My Feedback: (2)

Here is my electronic list

Futaba S9254 with Futaba GY401 for the rudder - servo mounted in canopy

Futaba S9452 for the other four servos

Hitec FM/HFD-08RD RCD3200 72 Mhz receiver

Futaba FP-T8UAP Trasmitter with FP-TP-FMRF module transmitter

Tenergy 2000mA NiHM battery on first switch

Added a second switch with same battery type wired in parallel- no change in symptoms

All ball links are smooth, no servo binding, everthing moves freely

Checked receiver antena tonight, it has continuity from beginning to the end. It is not routed close to any other wires. Its basically routed as best I think it could ever get.

Batteries have been checked with Triton charger. The checked out good.

Motor runs well.

Im still getting twitching from 2-3 of the servos that Ican tell. (engine, pitch and tail)

Tail belt is tight.

Everything on the heli is tight. Bladed and paddles are in track. No bent shafts.

The only thing that is odd is the tail vibrates at times and wont hold without a little right trim.

The other thing is Idont think I see these problems until the engine/rotor has been running for more then a few minutes.

Engine temp is 150 degrees. (I have a digital, infared or laser type thermometer that Iborrwed to check engine temp) Temp was taked right at the head and crank area of the enine.

Gyro is mounted with the supplied tape with small 1/8" thick piece of plexi glass betwee two layers of tape (sandwich). Ineed to change this to a small piece of metal at some point in time. This was done in hopes to eliminate this problem. It was originally mounted with only one piece of the double sided tape.

chadxp1

My Feedback: (2)

Hobby Man, that is a very interesting point. I never heard of static charge (newbie). Thinking about it just may be that as he heli seems fine the first flight but really shows twitching problems after flying for ten minutes or so. Im hoping this is the problem. Anyhow, what is the best way to reduce this? I read there is some spray agents that you can spray on the belt that helps. Other ground the tail boom. Is conecting the (-) side of the battery to a ground circuit connected through out the heli a good idea?

hobby_man

My Feedback: (8)

Make sure you do not have the FM antenna wire wrapped around carbon fiber, like a carbon tail boom support.

I just looked a 50 titan that had the RX grounded to the tailboom, I forgot to look at how he grounded it to the RX.

He quoted he read how to do it on a user group. Try searching for it

chadxp1

My Feedback: (2)

Thanks. I will get some anti static spray and spray the belt and drive gear. I will also look at the grounding technique.

Ill give this a shot tomorrow after work and let you know.

Chad

Gavin2407

Hi Chad

Hitec FM/HFD-08RD RCD3200 72 MHz receiver
Futaba FP-T8UAP Transmitter with FP-TP-FM RF module transmitter

IMO this could be your problem as TX & Rx is brand specific. I know I use JR equipment that can work with Spektrum gear but they're "joint venture" companies. Other brand Rx's with deal with signals differently that original brand Rx's. Is Hitec compatible with Futaba? Do they also share technology?

john josey

I have to agree with Gavin. Mixing brands can be asking for trouble, i know a lot of people do it with no problem but IMO it`s not worth taking the chance on anything that`s worth more than a good night out !

If you have to mix brands, make sure each brand has it`s 'own' crystal.

chadxp1

My Feedback: (2)

The receiver and tramsmitter work fine together. It even says on the receiver this works with Futaba Tx. Also this setup was in my 30 size Hirobo working fine with no issues. Iagree it would be nice to keep the same manufactures. Im using this setup unitl my DX8 comes in.

Thanks
Chad

hobby_man

My Feedback: (8)

I have that set up as well and it works great. If we all stayed brand specific, we would have no after market itmes.

chadxp1

My Feedback: (2)

No luck with the anti static elimination.  The problem definatly gets worse or shows itself when the RPM is high. I took the receiver of this heli and reinstalled it back into the Hirobo. My brother wanted the Hirobo so I gave it to him along with the transmitter. (Oh and the Hirobo took right off with this combination with no speratic servo movement)
Ill have to wait for my new Spectrum DX8 before I can start troubleshooting again. In the mean time I will take the Raptor apart and check everything over.

Ill keep everyone informed once I get back to flying it again.

Chad

chadxp1

My Feedback: (2)

Installed my new DX8. It appears as thought the problem has disappeared or is hidden. Im very happy. I like the DX8!

chadxp1

My Feedback: (2)

Raptor 50 running great thanks to mynew DX8 transmitter.

chadxp1

My Feedback: (2)

love the telemetry the DX8 offers. Temperature, receiver voltage, signal of both anttenas, and engine RPM.

zreimer164

I am having the same problem with my 50 titan, but not all the time, some days it twitches like crazy with the throttle and the pitch servos making it jump and other days not a twitch. I have always thought there was some electrical interferance or bad reception somehow. The twitching always stops when I start flying around. Never crashed because of it, but still scary. Any other ideas out there on how to make it quit