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HomeAircraftHelicopterCrashed? Discussion and Photos › Hard Lesson Learned
03-31-2005 12:59 AM  13 years agoPost 1
rob_k

rrApprentice

Castle Rock, CO

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I just got back into rc helis after a 12 year break. Got an R50, a couple of weeks ago and have been rapidly relearning how to fly. The technology has changed quite a bit with the new HH gyros and digital servos but, everything else is pretty much the same.

I knew batteries were a concern so, I got a larger (1100mah Nicd) battery and a Hangar 9 volt meter. I was checking my batteries after every flight. While hovering, I easily got 4 or 5 flights in without the batteries showing very low.

Next day, after one long flight of hovering on a fresh battery, I decided to get back into forward flight, I was unimpressed with the performance of the R50. The controls seemed soft without a lot of response. I was able to do a loop but, remembered my old GMP Competitor having much better performance. I was confused. I brought the helicopter down after just a couple of minutes and played with pitch curves, throttle curves, etc. (I live in Denver and figured I just wasn't getting enough rpm at this altitude.)

On the next flight, the tail rotor seemed very sluggish in right hand turns. I brought the heli down, retensioned the belt and checked everything over. The battery still showed about 5.0 V so, back up I went. This time, while doing an aggressive transition from Forward flight to hover, the heli went into an uncommanded pirouette. I hit throttle hold, let it drop about 10 feet to stop the pirouetting and then released the throttle hold and had full control again.

I brought the heli down, thinking it was still and head speed issue. I tweaked the throttle curves for more power, and went back up. (Battery holding at about 5 V).

This time, I immediately duplicated the aggressive move from forward flight to a hover. This time, the collective was slow to respond and the heli piroutted again. Unfortunately, by the time, I got the pirouette under control, I hit the ground. 1 broken skid, 1 set of trashed wood blades and, broken canopy nuts. (fortunately, I had no power on and hit pretty soft so, the damage was light.) I was confused as to what was happening though.

I looked everything over mechanically and was baffled as to why I kept losing control of the tail.

That evening I figured it out. I had heard that with low batteries, the gyro can reset. My battery still showed 4.9 V that evening though. I decided to check and see if I could duplicate the issue. I put load on the head with my hand while cycling the controls.....sure enough with just a little load on the head, the gyro reset itself.

My hypothesis is that the Hangar 9 voltmeter's load isn't realistic for helis. I checked it and it puts 160 mah load when on the receiver side and 320 mah on the transmitter side. I figure that with a couple Digital Servos and a gyro, we can see up to 1 amp or more. I put the battery on my Triton and discharged it at 1 amp. It fully discharged in 4 minutes!!!

Since then, I have cycled the battery numerous times to get an idea of what I can expect. I am now limiting myself to 1-2 flights before charging and don't trust the results of the voltmeter as much. The Triton seems to give consistent results during discharges so; I am sure there is nothing wrong with the battery.

The moral to the story is that with the new higher drain servos and gyros, we all have to make sure we understand how our batteries behave. I for one will be getting a much more sizable battery and will watch them much more closely.

I should have noticed from the "mushy performance" but, was unfamiliar with the R50 and flying in Denver. Hope this prevents someone else from the same dumb mistake.

As for the R50 performance, with fresh batteries it loops and rolls like I never would have believed!!! It will take quite a while for my skills to catch up with its capabilities. I have since had to put all of my pitch and throttle curves back where they were before this incident. It's a great heli.

Rob

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03-31-2005 01:04 AM  13 years agoPost 2
polyhedron

rrApprentice

Amite, Louisiana, USA

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I have all digitals on mine with a 2700mah and I get 3 flights easily. I haven't pushed it beyond that point, my voltage begins to show low voltages while in flight after 3 flights.

I have all DS811's and a 401/9254 gyro servo combo


--Matt

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03-31-2005 01:14 AM  13 years agoPost 3
rob_k

rrApprentice

Castle Rock, CO

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I only have a 9254 on the tail and 3010's the rest of the way with a GY401. That one 9254 seems to be a bigger drain than I originally thought.

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03-31-2005 08:37 AM  13 years agoPost 4
hepsibar

rrApprentice

Perth WA

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I only do 3 flights with my 60 and 5 digitals. 2400Ah pack.

You only have a 1100Ah pack.

On the 50 you can probably get away with non digitals on aileron/ elevator & throttle but you may notice a reduction in crispness. This would allow more flights due to lower battery drain.

I tried putting 9001 non digitals on aileron on my 60 but it felt noticably sluggish compared to a digital. I also tried it on the throttle but it was a bit slow.

As always with heli's, everything is a compromise! Digital performance = shorter flight times between charges.

Empty Coffee Cup

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03-31-2005 03:23 PM  13 years agoPost 5
Chavalo

rrApprentice

Mexico City

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I've got 3000 mah batts and get about 4 to 5 flights...more than that is pushing it.

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04-11-2005 08:25 PM  13 years agoPost 6
rob_k

rrApprentice

Castle Rock, CO

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Follow up:

I've been limiting myself to 1-2 flights on my 1100 mah Nicds with no issues and good luck.

Just ordered a new set of Fromeco 2400 mah LiIons with a regulator.

I'll post my results.

Rob

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