Questions about electric v. fuel

[M. Michael Meyer]

My son and I have been flying a Slo-V since Christmas. He has really gotten pretty good at it and would like to move up to a second plane. I have suggested an electric plane with ailerons, but he is somewhat interested in a fuel-powered plane. Can someone give me the pluses and minuses of fuel-powered vs. electric powered? Thanks. :confused:

[fhhuber506771]

The differnces are shrinking... Modern brushless electric systems with Li-poly batteries can NOW make a plane designed for glow power outperform the same kit with a glow engine. But to get that performance.. you have to pay a higher startup cost.

The Glow power has higher operation costs in fuel and support equipment. after a couple of years of operation, the electric would come out cheaper, even with expensive Li-Poly and brushless power. $15 to $30 a gallon fuel equates well to the cost of a Li-po pack.

There's no fuel residue to clean off the aircraft with the electrics.. and no worry of fuel soakng the wood weakening the model. (and making the covering so you can't get it to stick..)

Size of the model makes a difference, as well as availability of flying sites.

Large model e-power is very costly to set up.. $120 + brushless motor.. $90 + speed control and $200 for ONE set of Li-Pos for one model I have seen which could have been powered by a $120 glow engine... (but in long term.. he WILL save with the electric if a crash does not damage the batteries and motor...)

Its getting easier to find local places to fly with electric, and harder to find places to fly glow power. The noise of the glow models is one of the major factors. The preconcieved (but untru) idea of the electric being safer also has an effect on availability of flying sites. I can fly electric 80 MPH+ models at a local school.. but they won't allow a 40 mph glow powered model that weighs less, and would do less harm in case of an accident. (and its not because of the noise)

Finding local people to help out is a factor.. the majority of "old timers" in the hobby simply understand the glow models better, and many have preconceptions of electric models that are based on experiences with 20-30 yr old technology (underpowered, overweight annoying to even bother with) Once convinced of the performance of a modern electric power plane.. they will help out with learning to handle it, but won't know a lot about the power system if you have problems.

*********

Really, its now a matter of choice. E-Power is now competing in Radio Control Aerobatics at the AMA Nationals. Something that would have been insane to try with the technology of 10 years ago.. is now looking like a good idea.

My guess is.. another 5 years and the average "40 trainer" of today will be e-powered.

[BMatthews]

I quite agree with huber. However at this point electric performance costs more than glow performance. If you intend to follow the electric route then stick with it. But if you have a glow based club and flying site within easy reach then glow is cheaper to get into serious performance setups.

[mbk11]

Plus you really just gotta love the sound, smell, and all around experience of flying glow. It may be messier and all that but so are real airplanes. The engines, especialy a nice 4-stroke, just seem so much more realistic to me.....but I do fly both so there are obviously ups and downs to both sides. Basicaly if it flies it will be fun!

Matt

[Mendnwngs]

Electrics' a blast, for smaller planes. there is a point of diminishing return on electric as you get into the larger (.60 size +) models. Plus, Lipo batteries can be dangerous if mishandled. (Hey, so can glowfuel, but glowfuel wont spontaniously compust 20 minutes after a crash)

I personally like glow powered. I like the "geek-y ness" of fiddling with the engine.. Plus, on my trainer, at least, I can fly 20 minutes on a tank, bring the plane in, fill it within 30 seconds, and put it back in the air.

electric is more expensive off the bat, but you save money over glow in the long run.. Buying a Lipo battery, is like paying for a couple years of fuel up front.

Plus Items like fuel pumps, glow ignitor, electric starter, glowfuel, after-run oil, glowplugs, etc. doesnt need to get bought. :)

But hey. Get that awesome 4-stroke sound out of a brushless, and Ill be ipressed :)

Point being.. I cant clearly see a "superior" choice between Glow and Electric. There are pros and cons on each. You have to weigh them all yourself, and figure out which one suits you better. There are very high performance craft in both groups.

This is just my .02 :)

-Jason

[fhhuber506771]

I remember seeing an ad for a device to put in the plane... Y it with your throttle channel to the ESC and it "plays" an engine sound at power level proportional to throttle setting. So.. be impressed you can have engine sound with electric flight :D ;)

[aeajr]

My son and I have been flying a Slo-V since Christmas. He has really gotten pretty good at it and would like to move up to a second plane. I have suggested an electric plane with ailerons, but he is somewhat interested in a fuel-powered plane. Can someone give me the pluses and minuses of fuel-powered vs. electric powered? Thanks. :confused:

Hi Mike,

Responded to your post on teh other forum, so will put short form here.

Electric

No muss, no fuss with fuel.
Clean, quiet and odor free planes, cars, clothes and houses.
(Mom friendly?)

They tend to be smaller and slower, though you can get electics that go over 100 mph.

I find them very very convenient. I fly after work in a suit sometimes.

No need to know much about engines. Hit the trottle and go. Unless, of course, you like to mess with engines, then electics are no fun at all.

Overall they are fun and very neighborhood friendly.
:D

[fhhuber506771]

Another bonus to electrics... you are not tempted to stick your hand through the rotating prop to remove a glo ignitor or to tweak a needle valve. The majority of prop-cut hands come from these two operations.

If you go Glow... dip-paint your prop tips a BRIGHT color when balancing the prop. (not guaranteed to keep your fingers out.. but makes the arc more visible when the prop is rotating)

[spencer6891]

I generally agree with all of the above statements, but I believe you guys may be slightly mistating the advantage of li-pos over fuel. You must consider how much flight time you can get out of a li-po pack compared to how much time you can get from fuel. The li-po will not last forever, and most of the time will need replacing after a year or two, depending on how hard you push it. Now consider the effects of a crash on a li-po powered plane versus the effects on a glow plane. Li-pos don't like crashes. Glow planes don't carry $200 battery packs that are destroyed in a crash.

However, this can all be evened out if you go with more robust Nimh cells, I suppose.

[aeajr]

No plane, regardless of power, likes to be crashed.

Flight time?

Let's see, my Aerobirds are speed 400, typical parkflyers. They get between 7 and 14 minutes from 900 mah nimh cells. So let's call it 10 minutes for convenience. So if I replace them with a 2S1P lipo pack of equal weight that would be about 3000 mah, so I would get about 33 minutes of flight time per pack per charge. I think most people would take two flights on a pack rather than fly 33 minutes. That is what I typically see at our field.

Lipos are typically rated at 200-400 cycles, I believe. NIMH I believe are rated between 300 and 500 cycles. I guess a lot depends on how hard you push and how carefully you charge.

So, if you have 2 LIPO packs, and you get two flights per pack per charge, That should be good for about 800-1600 flights across the two packs.

Let's use 200 flights per year for the "average" flyer. At 200 flights per year, I would expect those packs to be good for 4-8 years.

I think flights is a better mesaure than years. Takes into account the variation of frequency between flyers.

[fhhuber506771]

Now lets look at costs per flight.. (assuming no crashes.. a very risky assumption at best)

Glow: $90 engine, $6 fuel tank, $20/gal fuel, $20 Glow ignitor (with charger.. cheap one), $10 ful pump (manual) $30 starter, $18 starter battery. $15 12 volt charger. (for the starter battery)

8 oz fuel per 15 min flight with a .40 if you are conservative.. so 128/8 (we didn't spill any) = 16 flights/gallon >> 4 hrs in the air (maybe) per gallon.

The typical .40 engine can last from 12 to 100 gallons of use.. depending on how you abuse them. Lets call it 25 gallons or 100 hours. (because its an easy number :rolleyes: )

:confused: This calculation's going to get complicated.. fast. :confused:

The average starter battery lives 2 years. The glow ignitor is doing good to last 3 years. (Its a NiCd.. and tends to get ignored in winter.. and be no good in spring)

Fuel tanks last about 2 years if you don't abuse them. (then the stopper "rots")

Some of the hand crank pumps are kinda cheesy.. if it lasts a year you are lucky... some people get really lucky and they last forever.. I've seen a lot of them fail in under a month.

OK.. 200 flights a year... (as above) thats 12 gallons of fuel ($240) 1/2 engine ($45) 1/3 glow ignitor ($7) 1/2 starter battery ($9) 1/2 fuel tank ($3) 1 hand pump ($10) = $314 in "expendables" (sort of expendable..)

Thats $1.50 a flight.

**************
Who with decent experience in E-power (mine has been all bad with old tech stuff...) wants to calculate the E-power costs? (I'd come out with $35 / 15 min flight if I used my history with electrics... But I blame bad equipment choices.)

[aeajr]

OK let's take a crack at the e side of things. I will try to look at what we might expect to consume in 1000 flights based on things wearing out or failing.

2 2s1p lipo packs at $50 per pack = $100
Assume provindes 1000 flights/500 per pack

1 lipo charger $ 50
Assume it fails at end of 250 chargers.

Speed 400 motors $10 each $50
Assume 1 per 200 flights
(I have yet to burn one up)

Electricity/wear on car battery ?? $20
This is probably too much but....

Speed control $30
Solid state - Assume lasts life of packs


That's all there is as far as I can figure and this assumes we are burning up 5 motors, the speed contol and charger over the 1000 flights/500 charges/250 cycles per pack.

$250 for 1000 flights. = 25 cents a flight.

Did I caputer this correctly?

If we did it for a brushless motor and speed control in speed 400 class, then we might add $50 to the costs if we assume they both fail at end of 1000 flights. Of course, like the charger and speed control, these should not wear out.

With brushless that would be 30 cents per flight total.

[fhhuber506771]

Yep.. looks correct to me. I have always known that long term electric had top be cheaper than glow... its the blasted start-up cost that makes you shudder.

The thing that kept me going back to glow instead of electric over the years was performance. And as I have noted before... the electrics are about ready to blow on by the glow power planes there.

I have seen an E-conversion of the glow power .30 size heli that outperforms my heli with a .46 in it... and he gets longer flight time than me even if I strap on a bigger fuel tank.
*****
edit.. same heli kits Century Hawk. His is e-brushless, mine is overpowered glow.

[aeajr]

Hang on. Someone will come on and dispute all of this, but that's OK. Makes for interesting reading.

One point you made that is often overlooked/denied by the glow jocks is all the "other" costs involved with a glow plane that electric flyers don't have to deal with.

Once we buy a battery, that is our fuel supply for 200-500 flights. You pay up front, then you don't pay again for a long time.

One thing that glow guys don't have to deal with is different size battery packs. One jug of fuel powers most. Electric guys tend to accumulate battery packs. But over the life of that pack, the cost is typically low. Lower than what we posted above.

So, I say that in the long run, it is about even and leave it at that. I don't think many people are doing cost per flight analsyis prior to buying their planes. But it is interesting to see how the numbers flow.

Would not be a reason for me to avoid glow planes if the mood struck me.

[fhhuber506771]

Its awful hard to put a smoke system on a brushless... (and if it makes smoke... you probably got a huge problem :eek: ) Till they solve that... glow and gasoline power will be popular.

[Mendnwngs]

Plus, (And I know Ill get blasted for this) Personally I feel that Electric *can be more dangerous* than glow.

All powered planes are not toys.. all can cause injury, and require a healthy respect. But, lets look at 2 quirks of glow. 1) To start, you have to prime the engine, put on a glow ignitor, and touch it with a starter (or flip it with a chicken stick) all of this takes place after you have fired up the electronics, and checked your servos and throw directions. and 2) Once the prop has been stopped (By ground, or even your finger *ouch*) its done moving untill you run the start-up sequence above.

Electric doesnt require anything but power to start. When you power up the electric plane, *if* the ESC 's arming proceduer fails, or if the esc doesnt have an arming safeguard, or even more likely if you have the plane armed, and "on" but with 0 throttle, something can happen to mae the prop instantly snap to life, with or without your hands there. And, unlike Glow, once stalled, an electric prop will keep hacking away untill its turned off.

Now.. Before you all get fired up.. Im *not* satying glow is safe.. Just a few observations of the diferences between the two, and from personal experiences. Ive been injured by an Electric.. Ive never been injured by a glow. (knock on wood) Because with glow (at least for me) you *know* when its on, and in a dangerous state. Theres no ambguity.

Okay.. Im going to go hide from the e-fliers now :)

-Jason

[aeajr]

There are smoke systems for electrics. They use them on the electic pattern planes.

[fhhuber506771]

There are smoke systems for electrics. They use them on the electic pattern planes.

Technology Rocks!... they're always making new stuff :D

Glow warns you with noise.. electric sneaks up on you. I've never seen a glow model hover near someone who could hear without having his/her attention. I have found out about hovering electrics being 20 ft behind me by the spotter at my side.
********
You do have spotters if more than one model is flying don't you? If not.. Why? Even just one guy back 30 ft from the pilot's boxes watching the action can holler a warning to all 4 guys (or more if your club/group allows) on the flight line.

[ivanc]

We do not have spotters at our field. We have rules though. We are not allowed to fly behind the established flightline which is in front of the pilot line, the pits and spectators. If someone is in trouble, he announces it. We also announce events like "Taking off", "Landing", "Low pass from the east/west" (our runway and pattern are east-west oriented), "On the field", "Off the field", "Trim flight", "I don't have it" :eek:, etc. We are supposed to look at the plane taking off for its maiden and/or trim flight as anything can happen.

[Joe Ford]

Hate to tell you this guys but your figures for converting to epower are WAY too low. $120 for a motor HA...more like $250-350, $90 for esc another laugh especially if you require high voltage (6s to 10s), then youre lookin at $400-500!!! ...that $200 per lipo pack is about right for smaller planes (.40 size) but the larger conversions youre talking $500-800 a pack...and you need more than one pack, easily 3 so there goes at least $600 according to your figure...go ask Ed Lyerly how much he spends per conversion...youre talking easily $1200-1500 and thats if you already have the lipos! Then you need a charger capable of charging those high voltage packs...another $200 EASY. And you guys are assuming your lipo packs are gonna last forever, you'll need new ones after that 200 flights if not before. Smaller planes (parkfliers/3d/pylon/etc) are much cheaper than glow but when you move up in size with electrics the cost SKYROCKETS...well beyond what a nitro plane would cost. Not hating on electrics, I fly both and love what each of them can provide. But you guys are comin off like its already decided that electrics are better...there is no "better" in my mind, its what each can provide you with.

[aeajr]

Hate to tell you this guys but your figures for converting to epower are WAY too low.

Guess you only fly big planes. For the rest of us, conversion of small glow planes to electric doesn't cost anywhere near your numbers.

[Joe Ford]

By small what do you mean? .25 size?

[pimmer]

I think that a lot of people get caught up in the "big plane" mindset. A big plane is easier to see and easier to control. This is only because it has to be farther away, and flies faster. It is a matter of perspective. My 30in EPP biplane flys so much more slowly that I can have it much closer in. As far as I can tell, the perspective is the same. A large plane fying farther away and faster = a small plane flying much closer in and slower. I used to have a 90 size UCD-3D. I could only fly this at the club, and it was like fying a big piece of styrofoam because it was so maneuverable and light. When I switched to the Tuff-E EPP plane it was remarkably similar to my UCD-3D, but much slower and closer in. I can do all of the same maneuvers as the UCD-3D, but I can now do them in my cul-de-sac. I would be easy for me to pretend that the airplane is much farther away and bigger and was flying at three times the speed. I have no intention of limiting myself to just flying at a club field by converting a large plane to electric. At the scales I am talking about, I fly ten times as much because I can do it by walking out the front door of my house. The motors at this scale are much cheaper than the glow engines, the batteries are cost effective compared to glow fuel, and the silence and reliability of electric (did I mention fying in my cul-de-sac?) are priceless. My motor never needs a glow plug, never has a dead stick (which opens up a lot of things I would be afraid to try with glow), my plane is as clean as the day I built it, I have enough packs to fly for as long as I want to, and until the neighbors actually look up to see the plane, they would be totally unaware that I was flying it (did I mention QUIET). The local kids love it. At time the plane can be seen from 4 or 5 streets away. I have had several people see it from far away and drive around to find out who was flying it. They are very interested in the hobby, the technology, and the possibility of flying RC with electric motors intrigues them. I point them to some online resources.

[Joe Ford]

Agree with you on the ease of electrics and ability to fly where nitro can not. Unfortunately though my electric forte is 1/2A pylon racers, F5D, and F5B...all of which are "loud" electrics and need to be flown at a club field...this is fine with me though since the club field is only 7 minutes from my house but who's counting. :) Its mainly due to high speed but trust me if I flew over your cul-de-sac with one of my pylon racers EVERYONE would know it was there...sounds like a router on steroids. :D Man I gotta get a parkflyer again...I've suddenly become jealous.

[kiswa]

Now lets look at costs per flight.. (assuming no crashes.. a very risky assumption at best)

Glow: $90 engine, $6 fuel tank, $20/gal fuel, $20 Glow ignitor (with charger.. cheap one), $10 ful pump (manual) $30 starter, $18 starter battery. $15 12 volt charger. (for the starter battery)
[sic]
OK.. 200 flights a year... (as above) thats 12 gallons of fuel ($240) 1/2 engine ($45) 1/3 glow ignitor ($7) 1/2 starter battery ($9) 1/2 fuel tank ($3) 1 hand pump ($10) = $314 in "expendables" (sort of expendable..)

Thats $1.50 a flight.
[sic]
Okay, I just had to note that your prices seem rather high, and some are not even strictly necessary. If you will:

Engine: $56 (what I paid for my TH .46 BB ABC with shipping)
Fuel Tank: $4 (10oz. Great Planes tank)
Fuel: $15/gallon (Local Hobby Shop - 10% nitro 70/30 synthetic/castor oil mix)
Glow Ignitor: $12 (with charger, from the LHS, decent one)
Manual Fuel Pump: $6 (same LHS)
Starter: Free (screwdriver with some old hose over the tip as a 'chicken stick')
Starter Battery: Free (1 arm power)
Starter Battery Charger: $0.50 (1 can soda) ;)

You really don't need an electric starter or battery or charger; it's an 'extra' not a necessity. Also, I'd like to mention that engines last plenty long. There are several people in my club flying planes with engines over a decade old. I'll go with a year being one fifth of the engine life to work with your numbers.

So... 200 flights a year... 12 gallons of fuel ($180) 1/5 engine ($11) 1/3 glow ignitor ($4) 1/2 fuel tank ($2) 1 fuel pump ($6) = $203

That's $1.01 per flight. I just think that's a little more realistic. Not trying to step on any toes here. :D

[aeajr]

So... 200 flights a year... 12 gallons of fuel ($180) 1/5 engine ($11) 1/3 glow ignitor ($4) 1/2 fuel tank ($2) 1 fuel pump ($6) = $203

That's $1.01 per flight. I just think that's a little more realistic. Not trying to step on any toes here. :D

I think your analysis is fine. We did the same thing for the electrics. Chargers don't typically wear out, but we expensed it over the life of the packs, just to put in some kind of number. I have a car battery charger that I have been using for 40 years and it works just fine.

We said 200 flights for a speed 400, but I have not worn one out yet and the plane has over 250 flights. Again, you have to use something.

However we are all trying to approximate to some rational number. I think yours are as good as anyone else's. Fine for discussion purposes.

[aeajr]

By small what do you mean? .25 size?
Sorry, I don't fly Glow. I don't know what a .25 would be.

If it is in the 10-24 ounce range, and the 30-60" wing span range, then I would say that might be about right. Those are common sizes for popular electric planes.

Speed 400-480 motors will fly those planes very nicely.

Speed 400 - $10
Speed 480 - $16
ESC - $16-$30

Battery Pack - $20-$30

Now, if I want to do that plane in brushless and have plenty of power

Brushless motor and speed control combo - $130
Multiplex Permax 480/6D w/Multicont 25A ESC
Should replace speed 400-Speed 500 class motors with more power
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXJCL0&P=7
up to 16 NIMH cells or 4s1P lithium.
Good example of a brushless hop up for this class of plane.

1500 mah 3S1P lithium to go with that motor - $45
good to about 12 amps
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXGHE6&P=ML
2000 mah 3S1p good to about 30 amps - $68
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHFG2&P=ML

Put this combo in one of the planes above and you should have a great performer.

It can probably handle larger planes as well, perhaps up to 32 ounces. With a gear box it might go larger. I am not certain of that. A $25 gearbox might be desirable on planes over 30 ounces Depends on what kind of performance you want.

OK, have we settled that point?

[Joe Ford]

.25 size planes are between 30-60" depending on the airframe/airfoil, weigh about 2.5-3.5lbs when using glow power (I'd assume around the same if one did an electric conversion, possibly less with lipos though) http://www.globalrcmodels.com/rc_model_power_planes/thunder_tiger_lazy_tiger_51.htm
here's an example that one of my buddies electrified, he used a Himax 480 size brushless geared, moves pretty good but I think nitro would be a bit faster and have better vertical. Think he got the motor for $100 or so, esc was $120?, lipo packs he made himself so was a bit cheaper than purchasing pre-made...total cost was a little more than nitro, so he would catch up cost wise vs. nitro. I was referring to .40, .60, and upwards costing the buku $...especially if you want comparable performance to nitro. They typically weigh 6lbs+ so you need a LOT more power to get em to do all the stuff a nitro bird would.

[aeajr]

Yes, the typical glow plane is larger and to electrify it would cost more than we were discussing.

I think, at least for the .60 and larger planes, if you are going for electrics, economics can not be the reason. It is still pretty expensive to take those electic. however .40s and down can be done within reason.

And the motors and speed controls are coming down all the time. Lipos are now approaching the price of NIMH cells and their abiliy to push amps is getting pretty good.

So this year it is economically feasable to electrify a .049 to maybe a .30 plane, which would be in the speed 500 to 700 motor range in burshed motors. Motor/controller would run $50-$100

Brushless would be in the $100-$200 range typically. Brushless motors should not wear out.

Battery pack would be in the 8-16 cell rNICD/NIMH range or 3S2p -5S2P lipo range. $50-$200 I would guess.

.40s are OK but not cheap. Above that we will call expensive.

Next year .40s and maybe up to .60s might be reasonable.

The year after that, who knows, maybe 100s won't seem too expensive.

That is how it goes with electronics. Faster, cheaper, smaller, better every year. And the batteries are finally starting to catch up.

But I just love the little slow flyers. You can jog next to them while they fly.

[ivanc]

Can anyone give me an idea as to what do I need to convert a GP Super Sportster 40 ARF to electric and how much approx. would it cost?