electric vs gas.

[Grossman56]

Hey Konrad, I think you're on to something there! Out here in cowboy country, land of the noisy 4x4s and the Harley Davidsons, not to mention larger caliber weapons, they'll still complain! You have to watch whose property you inadvertently fly over as well, there was an empty field across from the school that I would pass over when landing. One day the guy is standing out there, and I'm wondering if he plans on 'complaining ' or just watching, you never know with people. Last time I flew from there.

Grossman56

[doctormike]

I bought a Great planes SkyBolt bipe for my .91 4 cycle. After much going back and forth, I've decided to convert it to electric. The FMS Pitts is about the same size and weight, so I'm going to use the Pitts power setup and electronics. I'm not sure where that battery will fit. I love that 3 blade prop, too! Doc

[fhhuber]

Is that smoke for e-power?

I WANT THAT!

[RocketRobin]

My electric rig for my Great Planes P6E.

Cheers!
Rocket

[RocketRobin]

Gasoline does change as it is mixed (refined) as the seasonal requirements demand. The fuel is blended differently for the sub zero winter weather verses the 100°F+ summer heat. Most folks want their cars to start in the winter and not vapor lock in the summer. Folks are odd that way:rolleyes:

But the real killer is that the mass (center) of gravity is always changing through out the whole flight. Then there is the tune of the engine, its power changes though out the day as the temps and density change. When flying electric there are actual less variability between the variables, day to day and through out the year.

While I did dyno my engines while I was developing them. I can't actually say that I did any long term decay studies. But I'm sure that there was a decay in the performance of the engines even from the beginning to the end of one racing season.

Pump gas changes for seasonal mixes in some latitudes. We all hope that the octane rating is at least that which is advertised. Those of us that drive cars with high compression/boosted engines know that every time you pull up to a strange pump, it's a crapshoot whether you get a tank of high octane, or some run-off from the pig farm out back. Station owners think we can't tell the difference, but it shows up on the gauges, too. We know when they're shoveling it!

But I digress.

Lipos are a different fuel. They just totally suck arse when they're less than warm, and are essentially useless when cold. Then they have that crazy discharge power curve thing that just gets worse right after you take off. They wear out while as you fly (ever seen an EF1 racer run a battery for more than a one event? It's called "also ran".)
Lipos are, for the most part, convenient for city apartment dwellers that drive compact cars, like me :)

I'm not a pylon racer, but my club is a racing club. They burn nitro in all events except EF1. Apparently nitro is a good fuel to use for racing.... just throwing it out there that it might provide good performance, for events like the World Air Games, etc.

Multi-cylinder nitro power. If I was to compete in scale, that's what I would use (all I need is a house and a PU truck). I would run as much nitro as the engine recommendation and then add 10 points (runs cooler and more stable) and I certainly wouldn't worry about a bean counter calculating the fuel operating costs (and extra glow plugs) for my precious plane and its expensive nine cylinder radial engine.
We all have dreams :rolleyes:

Cheers!
Rocket

[martmichals]

I stand corrected about gas engines in that aspect then, Konrad. Thanks for the other perspective.

[Konrad]

Actually the loss of field is as a result of development.

Noise is for the most part an excuse. Folks don't like the idea of folks (Guys, grown men) having fun. I point to the fact that in suburbia folks are fine with the noise of lawn mowers and such as they know you aren't having fun. But as soon as the noise is associated with a fun activity then it MUST be banned. And the most convenient reasoning to ban is noise regardless of dB output.

Now don't think that electrics are quite! I have some that will wake the dead.

[Konrad]

Gasoline does change as it is mixed (refined) as the seasonal requirements demand. The fuel is blended differently for the sub zero winter weather verses the 100°F+ summer heat. Most folks want their cars to start in the winter and not vapor lock in the summer. Folks are odd that way:rolleyes:

But the real killer is that the mass (center) of gravity is always changing through out the whole flight. Then there is the tune of the engine, its power changes though out the day as the temps and density change. When flying electric there are actual less variability between the variables, day to day and through out the year.

While I did dyno my engines while I was developing them. I can't actually say that I did any long term decay studies. But I'm sure that there was a decay in the performance of the engines even from the beginning to the end of one racing season.

[wpmay]

Seems like this thread is missing the most important point. The AMA indicates that the number one reason for the loss of flying fields is the noise from IC engines. As housing developments continue to encroach on areas that were once more rural this will be an ever increasing problem in the future.

Bill

[martmichals]

I understand you Konrad, and that brings another point to the table, a gas engine doesn't really change, and neither does its fuel source. Gas is always the same, while lipo batteries may change over time.

[Konrad]

Don't get me wrong 80% power return after 2 years is still more than adequate for most sport fliers. It is just not what I will tolerate from my power packages.

[martmichals]

As we see there are a lot of good arguments, so I'll throw in a bit more. I find that gas aircraft as compared to electric equivalents are a bit cheaper, after the initial costs. Konrad brought up the point that electric batteries are effectively 2 year sources of fuel. With the batteries that I would have to use, I would have to pay upwards of 200 dollars for 2 years worth of flying. Gas, at its current price, is a cheap source of fuel with 200 dollars giving you the ability to buy, at apx. 3 dollars a gallon, 67 gallons of fuel, giving more than 2 years worth of good times. Truth to be told, gas is expensive to start out with, though.

[StormyDog1962]

Many great points but the main thing is to be enjoying yourself, for me I like all aspects of the Hobby from building a Balsa kit to putting on the covering to mounting the Motor or Engine depending on your power plant choice. I like to troubleshoot things when they don't go right and when I fix it I get a sense of accomplishment from it. Some people only want to fly and not mess around with the other aspects so for them Electric is the way to go, I say go for it. Just enjoy yourself and take out of the hobby the part you enjoy and avoid the parts you dislike.

[RocketRobin]

I think about electric power set-ups all the time, because that's what I fly, because they fit in my compact car.

I think if I traded in my compact for something like a PU truck, maybe I could have a big gas rig.

I remember I flew nitro back in the day. Lots of nitro! 50% boat fuel, the good stuff. Starts easy, runs cool, solid tunes and smells like power!

I was thinking; is anyone running NOS on their gas planes these days? If I went gas I'd have to have a GM1 switch on my Tx :D

Cheers!
Rocket

[Konrad]

There are a few errors in that publication. The most egregious was storage. You DO want to store your batteries at Half charge, for lipos about 3.85V per cell. This balances the decay on both the anode and cathode extending the useful life of the cell.

And in my opinion electric motors are much easier to size than the old glow engines as their power output is very linear. Now the issue is that there isn't or wasn't that much "Tribal Knowledge" regarding electric.

Now when somebody mentions a 40 sized aircraft I have to ask is that with a gutless OS 40LA, a rippen Nelson 40, or a performance K&B 6.5cc. I get the same dear in the head light with that question as I do with a 600 watt rating. Folks really don't know what they are looking at when it come to sizing power requirements Glow or electric.

I hope you all can see that there really is no equivalency as the power curves slope in opposite direction. They might cross at one point but that does not mean the power sources will respond the same as the load varies in flight.

One of the biggest hurdles is trying to get guys to stop think in terms of glow engines when dealing with electric motors. Try to think back when you didn't even know about glow motors. Learn to think about electric motors like electric motors!

[XF-15DCC]

Well this is interesting.....

http://rcmb.org/Electric_Info/glow_elec_bonus4.pdf

[tdevince]

I started in glow, never did gas. I've recently gotten back into the hobby and am converting many of my old glow to electric for a variety of reasons. The biggest reasons are convenience, lack of required support equipment at the field and its easier to clean the electrons off the plane than the oil residue of glow. That being said, glow does have some advantages. From a safety standpoint, bumping a throttle won't bring an engine to life. Also, I'm one of the few that actually likes the smell of glow exhaust. I will probably keep one or two aircraft in glow and continue to build the electric fleet as well.

[olwarbirds]

There is alot to take into consideration if you go fuel. That Yak 52 is a nice flying plane, but I definately would not go 2 stroke. You would get better results with the 4 stroke or even a 25-30cc gasser. You will need a glow driver and I for sure would be using an electric starter. So you would need a battery with charger, to power all that and a panel to tie it all in. Some kind of a fuel pump, be it manual or electric and dont forget a supply of Paper towels, cleaner and rags, extra glow plugs or spark plugs. A gallon of good 4 stroke fuel is around 30-35$, 12v starters are around 35-40$, drycell battery and charger are around $40, A decent rechargable glow igniter is around $30, fuel pump 20-25$, depending on which 4 stroke you go with it would run you 300-400$ for something decent like a Saito 1.20. Now add fuel tank, fuel line, glow plugs and tools. The same plane with electric equivalent, you will need an electric motor that produces around 1400 watts and running on 6S would be better and an ESC around 80-100 amps. You already probably have the lipos and charger..... DJ

[Konrad]

The "3 years worth of fuel" issue is not true any more...

I buy 4 X 3S 4400 mah packs for appx $120 shipped to my door.

You don't have to pay Horizon Hobby prices for LiPos.

What is true or false? Do you give your batteries more or less life span, and why?

I give all my lipos a 2 year life span at room temp. This is because the anodes and cathodes in the batteries deteriorate as a function of time so that they only release about 80% of their like new capacity of energy. This is for the semi-wet electrolyte lipo (what we use in our hobby)

Those 2002 cells were/are Kokam/FMA and Thunder Power branded.

All the best,
Konrad

[fhhuber]

The "3 years worth of fuel" issue is not true any more...

I buy 4 X 3S 4400 mah packs for appx $120 shipped to my door.

You don't have to pay Horizon Hobby prices for LiPos.