teleplayr

I'm a long time glow flyer, and I'm looking into getting into e-flight for a scale 4-engine bomber I'm making. I thought electric would be perfect - I never have to worry about a motor going out, no mess, no hassle of matching engines with the needle valves. Great! Now I'm adding up the prices of using the brushless motor setups...

Motor: $139
ESC: $130
1200 mah LiPo batteries: $52.50 per 3-pack

So if I want to run 12 cells on a motor, I'm looking at $479 per engine setup!

Even if I go up to a .91 size 4 stroke glow, I'm looking at $190 per engine. That's $289 difference. Even if you consider that I'll always be buying fuel, say at $22 a bottle, that's 13 gallons of fuel per engine I'd be able to buy before I match the investment in the electrics. And don't forget we're talking about 4 engines!

I could go with cheap batteries, and bring the price to around $320, but it still almost twice as expensive, and now I have cheap batteries in my bomber.

I'd like to hear other's opinions on the matter. I know e-flight is becoming more popular with Zagis and whatnot, but is it feasible yet for general R/C flight?

-Joe

BuzzBomber

My Feedback: (4)

Geez, a 4-engine plane is gonna be $$$ no matter what you power it with ! I think that's one case where you'd be really hard pressed to justify going BL. Going brushed/GB would be MUCH cheaper, don'tcha think? Yeah, they're less efficient, but sooo much cheaper in the short run. My personal amateur opinion is that now that we've gotten past the "this battery works in my r/c car, why shouldn't it fly a plane?" stage, electrics are becoming a viable alternative. I've seen quite a few larger e-power planes that were of similar cost, performance, and AUW to glow counterparts. Course, I didn't buy, build, and fly 'em myself, so I can't vouch for figures I was quoted . BTW, I see you're in Jefferson......practically around the corner.

teleplayr

Yea, lookit that My in-laws live in Green Twp, right next door. I fly out of Sparta.

Ya, I know any choice for a 4 engine bomber will be expensive, but for 4 e-setups I'm looking at $1280 - $1916, and for 4 glow setups I'm looking at $600 - $800. That's a HUGE difference in price.

The reason I'm looking at the brushless is because I want to swing a big prop w/o a gearbox. If I go with the less efficient e-setup, I might as well go glow and spend the same money and get more efficiency.

That said, I haven't done a ton of research into brushed setups. Maybe someone could point me to what I need. I'm looking to swing at the least a 12-14" prop, preferably a 3 blader. Yea, big plane

-Joe

BuzzBomber

My Feedback: (4)

I was just picking on you about the costs , 100% difference is a lot. Right now, I have precious little first person experience with the larger electrics, so maybe someone else will chime in here. I am convinced there must be a more cost effective solution, I just don't know exactly what it is......Funny you mention Green. That's actually where I am residing for the time being, at my parents' sheep farm. Where the heck is there to fly in Sparta, anyhow? I hang around the top o' NJ field at waterloo and fly my parkies in the sheep pasture at my house. Well, I'm just rambling at this point, but I figure I'll give it a bump to the top here so the e-power wizards will see it.
-Matt

e-bird

Not yet wait till you get about 4-5 birds with controllers and
I have 5 packs of 6ea 1020's . But Archie Bunker had one son in law that didn't work I have 2 now do i leave it for them. CU

Matt Kirsch

My Feedback: (21)

LiPolys are still not quite there yet for larger applications. They're simply too expensive to use in the quantities you need. In your case, I'd recommend Sanyo CP2400SCR cells, all the way. They're top-quality, inexpensive, and robust. You may not get lots of flight time, but you can recharge them quickly and get back into the air.

I have to question your "twelve cells" assumption for the LiPoly configuration. Is that four 3-cell packs connected in parallel, or 12 cells in series? Either way, the pack won't even come close to producing the power of a 4-stroke .91. If the plane is designed to fly on four .25 2-strokes, yes, but not if it's designed for four .91s.

Also note that brushless doesn't necessarily mean "gearboxless." Only certain brushless motors, mostly the outrunners, are generally run without gearboxes. Most motors can benefit from a gearbox. However, four AXi outruners will prove to be a simple, relatively inexpensive brushless option. The problem with a geared brushed motor is that at the size you're talking about, it'll cost just as much as a brushless.

Part of the reason it seems so expensive is because you have expensive tastes. The other part is because you're new at this, and really aren't sure what you're doing.

What you need to do is start over. What are the stats on this plane you're building? What engines was it designed around?

teleplayr

Matt:

Thanks for the great input. I was just picking the .91s out of the air to use as a price point example, not to compare their power to the electrics.

Anyway, the design is either a 102" or 122" bomber, depending on how ambitious I get. There isn't a premade set of plans available for this size project, but Nexus plans has a 90" version that uses 4x0.20 glows. So, I'd likely need in the .30 to .45 range for 2 stroke glows.

I was looking at the AXI outrunners today; that's where I pulled the prices from. The 12 cell number came from the number of cells recommended for the outrunners.

As you correctly guessed, I have no idea about electric planes. I ran R/C cars competitively for most of my youth, but that was easy. 6 cells and a brushed motor.

And yea, I have expensive tastes That's always been a trouble, I research stuff and find out what's good, then find out how expensive it is!

Thanks for the advice,

-Joe

ampbomber

My Feedback: (7)

Let me tell you a little story.
In '95 I started a B-29 project. 115" span on 4 OS40FS. The plane flew in '97 at Top Gun and was lost on it's 7th flight ( #4 out) too slow and snapped. A month later I sold all my "sludge pumps" and began an electric B-29 which ended up being the Soviet Tu-4 copy.
The Tu-4 specs are:
115" span, 28 lbs, four MaxCim 13Y brushless, geared 2.73 turning MAS 13x10 wood electric props ( last year we used custom 13x9 four blade) and 12 P3000 NiMh cells per motor.
The electric version has 102 flights on it and is still in excellent shape. This year we are flying a new Tu-4 which is the Chinese AEW turboprop version. It's electric also. The electric project is starting it's 7th year.

The IC version doesn't exist any longer. It was less expensive in the short run but lasted only a few flights ( and I never did get the oil off of it). Both electrics are flying today. The electrics are a lot more expensive but a big bomber project will take you a long time to finish. If you start today LiPos will be less expensive in a year or so as you reach completion of the project. You won't need to invest much at the beginning and can spend as you go.

The objective would be to pick a subject aircraft and talk to motor mfg to be sure it will be powered corectly and then start building.

To become accustomed to the electric set up, that I was going to use, I purchased a Hangar 9 Cub and powered it with the same motors I was going to use in the Tu-4. I would suggest you do the same because you will answer a lot of installation questions fiddling with a sport plane running on the system for your bomber. The gearing and cell count will be different but the wiring ,etc will be the same. Also, you will have an electric to fly while you are building the bomber.

Pictures can bee seen at : http://www.scaleaero.com/maiorana_elec_scale.htm

teleplayr

Great story! That's precisely the reason I was looking at electrics in the first place. I don't want to lose a year of my life to an engine out. Pilot error I can live with.

So you're suggesting I contact the motor mfr, AXi for instance, and say hey, I'm building a 122" bomber, expecting a 30-40 lb all up weight, what kind of motors/batteries should I use? Then take that info, and find a simple kit to test/get used to the setup?

Thanks!

-Joe

ampbomber

My Feedback: (7)

Shoot for under 30 lbs. My AEW Tu-4 is about 30 lbs and the wing loading is 58oz. We are working on going LiPos and loosing 2 lbs. The Tu-4s are 1150 sq in. 56 and 58 oz wing loadings so a 120" bomber will have to stay around 28 to 30 lbs ready to fly.

Don't know of any kits of bombers that large.

Matt Kirsch

My Feedback: (21)

Teleplayr, the cost of powering your project just went down

The "Gary Wright" power system, as I call it, is a good replacement for a .25 2-stroke. It spins a 12x8 prop, though only 2-bladed, and would be good for a lumbering 4-engine plane, provided you don't get too wacky with extras and end up with a bomber that weighs 25 lbs.

It's a brushed system, starting with the $20 Kyosho Endoplasma motor. To that, you add a Great Planes GD600 gearbox (

eflyer2

Teleplayr,

I wasn't going to respond to this thread because I believe that everybody to his own thing and people should not get negitive about somebody elses likes or dislikes, but I could not help myself.
I'd like to tell you a story-

I got into R/C flying to spend more time with my son and grandson, they got into it on an impulse and bought a P-40 trainer w/ all the stuff that goes with it, cost him about $500.00 dollars, the guy at the hobby shop told him he could fly it in any big field, it was so easy to fly that they would be in the air and doing tricks inside of an hour, ya, right.
So after doing a little reading he decided to go to a club and get some information, ( smart kid ) at the club tey grined and told him to join AMA and then he could pay the one time joiners fee of $100.00 and first years dues of $125.00 ad then he could fly, so he did and became a member of the R/C flying club, BUT he can't use the field untill he can ROG, Solo, and make a good landing three times in a row without a mistake, so he has to take flying lessons, oh, but the lessons are free, he just needs to RENT the buddy box and cord frm the club, so now he has close to a thousand dollars in this glow hobby and he has not flown yet and belongs to a club and can't use the fields and come to find out after the fact my 11 yr. old grandson can't touch a plane or transmitter on the club property untill the age of fifteen.

I on the other hand bought a GWS Tiger Moth for $54.00 and a flight pack from AeroMicro for $$91.00 dollars and was flying at the local High school soccer fields in a week, I now own and fly five electric planes, batteries and chargers and building tools for far less than my son has invested in the glow plane sitting on a shelf in te basement, I just bought my kids a Tiger Moth and told him o try to get his money back from the club.

In this case which would you consider more costly, glow or electric.

Just because I buy a five room ranch for $200,000 doesn't mean you can get a 12 room house with 4 car garage and swiming pool for "Just a little more".

Personally I think you should stick with glow planes.
Thats my 2 cents.

teleplayr

That's an interesting story, but I don't understand why, after the story about how evil the PT-40 was to your grandson, and saying how great electric has been for you, you recommend I stay with glow.

Is it because I'm already an established flier and won't deal with the problems your grandson had? Or is it just a story you wanted to relate?

-Joe

eflyer2

Joe,

You might want to go back and reread my post, of course I wasn't saying that the PT-40 was evil, It's a well known, well liked trainer, nor did I imply that it imparted some ill on my grandson, I believe we were ingaged in a debate about the cost of flying Glow planes vs. Electric, I would think that point would be clear to most of the readers of this forum, the fact that the PT-40 and the related gear cost $500.00 dollars and the cost of joining a club ($225.00) and the AMA ($58.00) as opposed to a comparable electric like the Sig Rascal priced at $160,00 plus the electronic gear ($80.00) and a couple of batteries and charger at $75.00, and no need to join a club makes E-flite a LOT less expensive than glow flying, plus glow planes are messy and noisy, that's why most people don't want liquid fuel R/C toys in their areas.

The reason I suggested you stick with glow planes is because you mentioned that it would be cheaper for you to complete your bomber project using gas powered motors, and glow flyers tend to be elietist and frown on E-flight like it was a passing fad, I also have a dislike for whiners and complainers and would rather you be one of them (glow flyers) than one of us, speaking for just myself of course.
Have a great day.

teleplayr

So are you calling me a whiner and a complainer because I posted an observation I made about costs and asked the experienced e-flyers to tell me if e-flight has become more feasible and I made a mistake? It's ridiculous to assume all glow flyers are elitist and hate e-flight. I've been flying glow for 10 years, and the first thing I thought of for my bomber was e-flight, so I came here to learn about it.

Speaking of elitist, what kind of statement is, "[I] would rather you be one of them (glow flyers) than one of us" As if e-flight is some kind of boys club that only certain people are allowed into.

And I don't know what it's like by you, but here we have to join AMA and a club to fly planes regardles of whether they're electric or glow. City streets make a bad place for planes.

-Joe

eflyer2

Hello Joe,

Relax a little, where I come from kidding or BB as we call it is commonplace and if your going to play with the big boys you have to learn to take it as well as dish it out.
When I suggested you stay with glow engins I ment as far as that project was concerned, anybody can see that the cost of four brushless motors for your bomber was going to be high and that glow was a better bet unless you were willing to settle for brushed motors.
As to the eleitist statement I made, I should have been a little more general in pointing a finger at any one person, but it is true that most glow flyers in my part of the country look down on E-Flite and anybody connected with it, although that is starting to change as more people realize that electric is the future of R/C flying.
As more and more land is sold off for building, less space is left as a buffer between flyin fields and the general public, noise becomes a factor and the only way to avoid loosing flying rights is to keep the noise down, that means restricting flying times and useing more electric, it's not hard to see the writing on the club house wall.

I am lucky in that I live in the suburbs ( used to be the country ) and have a few open fields tat I can fly in, also a couple of local school systems that have baseball and soccer fields that can be used to fly at when the kids aren't playing so I don't need to belong to a club, It may come to that some day but not for the forseeable future.

So my friend, feel free to take a cheap shot at me if you are up to it, but let me warn you, you might enjoy it as much as I will to receive
it.

I've said it before and I'll say it again, I love making new friends over the keyboard.

Have a great day joe, Eflyer

teleplayr

I've got no call to take cheap shots at anyone. I just didn't appreciate the insinuation that all glow flyers are elitist and hate e-flyers, and especially don't like the insinuation that I was one of those.

Anyway, enough of this. I didn't come here to argue. I'm going to continue my research, because I still feel e-power will be the best thing for my bomber. I'd just like to find the most cost and performance friendly solution.

-Joe

eflyer2

Hi Joe,

I am sorry for getting on you the way I did I really didn't mean to upset you, and I wasn't arguing with you, just pulling your leg a little.

PS:
I think you should go back and read te post that Matt Kerish sent you, It sounds like the answer to your problem.

Eflyer

eflyer2

Joe,

One more suggestion, while your getting your bomber project off the ground ( no pun intended ) , think about getting yourself a cheap park flyer like a Slow Stick or Tiger Moth from GWS, you can have the plane in the air for under a hundred and fifty bucks and you can have some fun while you learn a little about electric flying.

Derek_TX

My Feedback: (1)

After reading the thread and the strange flame-up I have a question to ask:

What is the objective here?

Several potential answers seem possible...
First, you want to build a big 4 engine bomber that weighs 30 lbs. You would like to power it electrically.

Or, you want to build an electric 4 engine bomber that is big. If so, start with the idea of lighter structure to begin with and hope to get a 20 lb plane, instead of the stronger gasser style. No need to fuel proof and the vibration levels arent close to the same, so all satructures can be ligter. Lots of foam, glass & carbon.

Or lastly, you just want a 4 engine electric plane... if that is the case, geared speed 400's would be plenty on an 8 foot lightly built bomber. Or you can use speed demon gearboxes and gang up a couple cobalt 400's and swing some big props cheaply, very cheaply.

goofup

Teleplayer: "I know e-flight is becoming more popular with Zagis and whatnot, but is it feasible yet for general R/C flight?"

In your case, no, but then I wouldn't call yours a "general R/C" flight application.

Derek_TX has it right- if you want a huge electric 4-engine bomber I'm sure it can be done, but I think you're gonna have to start with a plane designed (or built) with electrics in mind from the ground up.... very light.

(I did a Google search and didn't find any, but HL has a nice electric 40" twin-engine B25 . I know that's not what you want, but hey, I tried...).

teleplayr

The idea is to have a plane in the 100 - 122" size be electric powered. I have no clue what the target weight for something like that is. I was actually going to ask about the differences in building a craft for electric power, as this would be my first e-project, but thought that should go in a different forum.

heheh thanks for the try, Goofup. Nexus plans has a 74" Lancaster made for electrics, so I may scale that up.

Thanks for the advice, everyone.

-Joe

Peter Khor

My Feedback: (4)

Scroll down to multi-engine:

http://www.flyelectric.ukgateway.net/largesum.htm

Notice 14' B-29 model on speed 700 brushed motor ($$$ though).

Also, 16' JU52 info over at:

http://www.torcman.de/index_e.htm

click on events, Elektroflug WM 2002 in Winterthur / Schweiz

Alson, video here (plus big models again):

http://rcgroups.com/links/index.php?...at=200&id=4143

Not cheap, but something to begin with.

smokingcrater

i'm generally pro-electric over glow, they are simply cheaper and easier for a beginner to start flying... BUT....

imagine the great sound of 4 - 4 strokers firing in tandem... send me a video (or just audio file) of this once it is flying!!! Go glow, a great plane like that deserves the noise.

teleplayr

Yea, this was the one reason I'd go glow. However, the thought of losing an engine, then the whole plane, does not give me good vibrations

Also, if I can get the outrunners or a good gearbox setup, I can swing big props, which should still sound really cool in tandem.

-Joe