harttvboy04

My Feedback: (32)

At the time a dsm2 2.4 ghz rx was in the plane. It will get a newer jr 9 channel either 921 or 922. My belief is that either the plug cap got water in it, the rpm sensor on my dle ignition got wet or both/all connections had water that created enough of a bubble to kill the signal

PacificNWSkyPilot

My Feedback: (19)

If the cylinder head is straight down, then I'd look no further. Remember the old metal tabs we used to push against the head of the spark plug on our old lawn mowers to shut them down? A Glass of water can do the same thing - it grounds out the plug. A lake full of water? You get the idea. I'm thinking that some silicone judiciously applied around the plug cap and sealed well around the ceramic section of the plug will seal it up enough to rectify that situation.

Water shouldn't affect the sensor, as it doesn't affect magnetism, and the sensors on the gassers are pretty well sealed. A sensor with a crack in it is possible, but rather unlikely. I think the simplest possibility is most likely the one.

But it's not like we're never surprised here.

Let us know what you find!

~ Jim ~[8D]

Charlie P.

I've got three 2.4MHz Tx and no 72KHz still in use.

Note that a spark broadcasts on ALL frequencies; right up into the visual teraHertz spectrum.

Muttdog

I can certainly understand water grounding out the plug and shutting off the ignition but that creating noise that caused a failsafe situation to occur in a receiver does not make sense to me. Once the plug is grounded then the noise is grounded as well and should be null. Whenever I see noise causing problems it makes the control surfaces flutter and act erratic, not send a RX into failsafe. At least that is the situation Ihave seen with my RX's. I use JR 8103 that I converted to 2.4 with a Chinese branded module (FrSky) and receiver. I did have the failsafe set up on the old JR receiver but never ran it on gas and it never had it kick in to test it. I have only had my failsafe kick in once on my 2.4 setup but that was because someone (me)left the radio on range test mode before taking off. It was kicking in and out as the signal was going in and out before she finally hit the ground. That was a hard lesson to learn.

PacificNWSkyPilot

My Feedback: (19)

Ahh, failsafe. Yes, that's different. I was concentrating on the engine itself.

The simplest - and most common - cause of going into failsafe is a power interruption. You might start by shaking power cables between the batteries and the Rx, or shaking the plane while watching the lights. Not sure which is the next most common. Interrupted signal, I'd reckon. The 8103 is a GREAT radio, but there might be some issue with the 2.4 FrSky module and/or RX. Range check first?

I'll be curious to hear what you discover.

~ Jim ~[8D]

ahicks

My Feedback: (2)

Regarding failsafe/brown outs, battery cells dropping out of a pack happens. A lot of guys getting knocked down trying to get too much out of single AA size NiMh battery packs as well? That problem often takes out a second plane... prior to figuring out what took the first one out. If you're using one, check it out and verify (for sure!) you don't have too much drain on it. They are the wimpiest available battery chemistry's and very few people are mentioning that! Found that out the usual (hard) way!

azalner

My Feedback: (8)

+1 what he said. That's why I switched to A123.

Al

ahicks

My Feedback: (2)

Regarding switching to A123, I wrote this in another post this morning. Some might find it interesting?

If you're interested in soldering up your own packs, here's a link to where I just bought enough cells to finish my fleet's conversion (from dual NiMh). He's stateside, which is what I was looking for this time around, seller name is "voltmanbatteries". These are genuine "A123" to the best of my knowledge. Cells are going for 9.95 apiece. I ended up screwing up my order somehow so I ended up calling him. Nice guy to speak with...

http://www.ebay.com/itm/NEW-A123-BAT...item5ad8c47a6e

harttvboy04

My Feedback: (32)

I was using a 3000 mAh LiFe pack from Hyperion

PacificNWSkyPilot

My Feedback: (19)

More commonly, it's a bad connection. Check the simple stuff first.

You can always over-think it later, if you've got some spare time and are feeling obsessive. That's the order I do things in.

~ Jim ~

Muttdog

I have had zero problems with the radio. As I mentioned before the only time my failsafe kicked in was when Itried to fly when I left the radio in range check mode. Totally my screw up and nothing to do with the radio. I chose the FrSky module for the JR radio after extensive research and feel this is the best one. It also has the lowest low voltage cuttoff of just about any brand receiver out there and it is true frequency hopping technology (RC model reviews did a full spectrum analisys on their site). I did not mind popping for the JR/Spectrum module but the receivers are outrageous in price and simply too much for me. I have 2 telemetry receivers and one standard and they all work great, never had a problem. I love the 8103 radio and now that it is 2.4 I could not be happier. Interesting discussion on the batteries. I am using AANiMh packs for my GSS with 6.0v on the radio and a 4.8V pack for the ignition. So far so good with the longest flying day about 45 mins to 1 hour from fully charged with no issues.

ahicks

My Feedback: (2)

A note, 4.8 vs. 6 volt NiMh? There is no difference in the amperage available to the receiver. Only the voltage. Going with an extra cell does nothing for you regarding the pack's ability to provide more brown out resistance. The only way I would run NiMh in a plane this size would be to run 2 packs (both powering the receiver).

Obviously, guys are getting away with single packs. Others aren't so lucky. Most that have done some homework on the subject don't consider trying a good plan any more. Just sayin. If you haven't yet, now might be a good time to read up on it so you can make your own call...

prr6100

I fly a GSS with a Zenoah g38 with a mag so I don't need an additional battery. i use Nimh 2300 and 6 volts, are the 123 batteries that much more reliable? I am considering upgrading, the servos are Futaba 3310's except on the engine. did you have trouble and decide to replces your batteries? Thanks

azalner

My Feedback: (8)

I became dis-illusioned with the NiMH for several reasons.

1. They don't last very long. I used to run NiCd's for 3 or 4 years, not NiMH.

2. Fast charging only accelerates the aging process.

3. They lose charge when sitting. I had an A123 that I charged in May sitting on the shelf. When I checked the charge it was at full capacity!

Others on this forum have pointed out reasons that I hadn't even thought of. My $.02.

Al

PacificNWSkyPilot

My Feedback: (19)

A 6-Volt pack ABSOLUTELY helps. The RX monitors the voltage, not the amperage. To start with, 6 Volts is 1.2 Volts further away from the 3.2 or 3.0 Volt brownout threshold than a 4.8 Volt pack is, and the 4.8 Volt pack is only 1.8 Volts away from it at its best. The 6-Volt pack does PLENTY for you; its extra voltage provides a substantial amount of brownout protection all by itself. A bigger 6-Volt pack even more so. I'm not dissing those who use two packs, or larger batteries and Voltage regulators. Those are all fine preventive measures, albeit a little overkill in my book. I understand why the guys who have large, expensive planes use them as a matter of course.

Guys with a Giant Super Sportster shouldn't need anything that extensive. I'm careful with my power connections, and I never have brownout problems. I buy my packs from Radical RC, and have all good luck with them. I run 2600 mAh packs and up whenever possible. Common-sense stuff that doesn't break the bank. I change my battery packs every two years. Usually I change my fuel tubing at the same time.

~ Jim ~[8D]

ahicks

My Feedback: (2)

Yes, loosing an awesome gas powered Funtana, then nearly loosing a gas powered profile (67" OMP Fusion) taught me that a single NiMh powering a receiver was not a good plan. You can see by the type planes here, I'm not just running around the race track and doing touch and go's. They're pushed pretty hard at times. I did try the 6v. trick myself, so I know first hand it doesn't work - before finding that out researching what the heck was going on. I was so far into making the NiMh work at one point, the profile plane taught me that in a brown out scenario, if I released the sticks, no matter what the plane was doing, I would have a chance to recover from a brown out, giving me a shot at cooling it to get it in. The draw from the servo motors would stop, giving the receiver enough voltage to function...

Lipo has been a pretty popular alternative, but you need to do something about their voltage prior to it getting to the receiver - voltage regulators. A lot of guys didn't want to mess with that. Now, we have the A123's. No regulator needed. You can feed most later model (6v.) receivers and servos direct. Those that have invested in figuring the A123 out have been won over easily over anything else available. .

ahicks

My Feedback: (2)

Jim it monitors the voltage, but the servos are going to drop the voltage one way or the other. The battery simply can't produce enough power to stay up with them in a lot of cases. No guessing here. It's a fact.

Like I mentioned, keep flying them if they're working for you, but you would do well to do some reading on the topic.

Regarding loss through wire/connectors, I ran 2 voltage taps on a single 6v. pack, powering 2 switches, which fed the receiver through the normal input and the second through a Y harness on the rudder. NO DIFFERENCE.

prr6100

I better print these all out and study them more, thanks,

PacificNWSkyPilot

My Feedback: (19)

Single NiMh packs always work for me. And my flying buddies. Never a problem.

If you're running a plane with a bunch of high-draw servos, you have to factor that into your power system. If your servos are drawing so much voltage that they're browning out your Rx, then something's wrong. A high-draw system SHOULD have bigger packs and voltage regulators, or duplicate packs, etc. If you're running a big electric and powering your Rx off the same LiPo or LiFe, you're asking for trouble if your voltage goes low, or if you're using high-draw servos.

You can't just lump all planes into the "you've gotta have an overkill electrical system or you'll crash" mentality. That's chicken-little stuff. The sky ain't falling.

Smaller planes with less demand can do just fine on a standard system. Most 40-sizes can run fine on a single 4.8 volt pack. Up the size, up the servos, you up the demand.

Big planes with big systems, or these 3D monsters they're creating with high-draw everything, they're a totally different animal. If you have just one or two of the 8311A servos or bigger, you shouldn't be running anything less than a 2500mAh pack, and preferably a 6-Volt at that.

There's a reason most two-story houses now have 200-Amp services to them. With all the new electronics we use, and the heavy demand from our new, more powerful appliances, it's a standard item now. Smaller houses can get by with a 100-Amp service. It's the same with planes. Use common sense when you're planning out your onboard system.

A lighter wing loading is preferable whenever possible, but not at the expense of the power that keeps your plane in the air.

NiMh are fine batteries, but it's important to do your homework and buy certified packs from reputable people who have a good reputation among your fellow flyers. As I said, I fly them, and have zero problems. I bought a mystery pack a year or two ago. It was crap. Back to Radical RC, and count the money I lost as a lesson. (The guy wouldn't return the money, and told me I was doing something wrong. yeah, right.) At least it didn't fail in the air.

You don't need to spend yourself broke to insure your plane won't brown out. Browning out is EXCEPTIONALLY rare, and I've always maintained that people who check their batteries, pay attention to detail when they're building, check their batteries at the field, and don't take stupid chances ( "Oh, just ONE more flight should be okay.") like flying again after a number of flights, they're the ones that never experience brownouts. Those who don't go the extra step or two, well, they're obviously okay with taking those chances.

I know more about this topic than five other guys put together. I never, ever have had brownout problems, and ahicks, you stirring things up doesn't change that fact. If I'm the one who DOESN'T have brownout problems, and you ("First hand") DO have them, who should be doing the reading? I did the reading long ago, and I retain what I read. As an engineer to boot, I can attest to the fact that muddying the water with hysterics and vague, unsupported claims doesn't change the science.

Last, but not least. This is a GP Super Sportster thread. THIS discussion belongs in the other threads (Spektrum, JR, Futaba threads), where it's already been hashed and re-hashed, argued and re-argued to death, for years and years now.

~ Jim ~

harttvboy04

My Feedback: (32)

Hi all, 

ahicks

My Feedback: (2)

Jim, I've made my points and believe them to be correct. Though I'm willing to discuss this further, I'm not going to argue with you. I've already proven to myself the relative merits of doing that the last time you disagreed with me.

Burying this information in the tech areas just a few care enough about to read is not going to get it out to guys that MIGHT need it. If you don't think you do, great! Happy flying!

-Al

PacificNWSkyPilot

My Feedback: (19)

Logic like THAT would mean total chaos to the mods.

It also derails threads.

This a great thread, about a great plane. About a Great Planes great plane. A lot of guys like this plane, and I like helping them and sharing knowledge, whether they be newbies or old timers.

~ Jim ~

Macrizzleh2

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Kostas1

I agree with the fact that two battery packs give more safety while flying, either you fly a gas-powered Giant airframe or a small trainer with a 40 size 2-stroke glow engine.

But in many occasions, two packs, connected paraller and pluged in the receiver slots may give more hassle to deal with.

Personally I go with a single pack of 4.8V in every airframe with a wingspan no more than 1.7m or no more than 5 servos installed, but
on larger airframes like my Giant Super Sportster with aSaito FA-150S I use x2 4.8V NiMh Hobbico Hydrimax 1.650mAh's packs.

Kostas1