I'm building a giant scale B-24 Don Smith plane. I would like to power it with electrics. Is there any site that can give me a good basic schematic to get started. I know nothing about what do get for this plane. I'm looking for a site that will take me by the hand and lead me from beginning to end. Some site that shows, here's the battery, here's the engines, here's how you hook them up, etc. You need this size whatever for this size airplane, you get the picture. I've tried some electric sites and there is a lot of info that would take me months to absorb. I was a Math and Physics major in college before I was thrown out for messing around, so numbers don't scare me. Just would like a site to cut down on the studying time.

Thanks in advance

Tally Ho

Dave Y.

Where'd you go to college that they would through you out for messing around? And what did you do?

I was attending Cal State Northridge in the mid 60's. Then it was known as San Fernando Valley State College. I was OK for the first 2 semesters then screwing around, not attending classes, partying, grades dropped and I was kicked out.

Oh I thought you meant recently. They must have been stricter back then. Sorry for getting off topic. Have you build many rc planes before?

No, this is my first one. I'm 63 and have been building static models for a long time. I use this building time for relaxation. Yes, I do have patience now.

Cool project. I just started gathering data for a B-17. Without getting crazy, the biggest motors would be a 5330/250 (53mm dia. x 30mm long stator, Kv=250 RPM/volt) which will give about 14 pounds peak thrust each. Many mfg's offer a motor this size and range in price from $60 to $270 for Axi. The Axi has about 30% more power and runs cooler.

Choose the prop first. Then find a trainer which is 1/4th the flying weight of the B-24 with as close to the same wing loading as possible, build 1/4th of the power system and fly it.

Dave

No, there is no such site. If you use the search forum you can look to see if someone has done a build thread for this plane. Then you will see exactly how to build that plane and power it from start to finish.

If you want to understand how an electric power system is sized, and what all the parts do, then read this e-book on electric flight.

> EVERYTHING YOU WANTED TO KNOW ABOUT ELECTRIC FLIGHT
> http://www.rcuniverse.com/forum/m_7100376/tm.htm

Hi Dave, I noticed you said that you have never built an RC plane before, but have you ever FLOWN an RC plane before? If not, I strongly suggest you look into finding a club near you that will give you an introductory flight, and maybe some flying lessons before you attempt to build and fly a B24.
There are many beginner type airplanes, and many good simulators on the market that will go a long way in helping you to become a successful RC pilot.
The fastest way to lose interest in this wonderful hobby is a bad first experience, or several bad experiences.
Learning to fly the right way, and with much success right from the start will go a long way in your level of enjoyment.

If you're already an experienced pilot, and just looking to get into electric power, then disregard the above .

As far as power system setup, there are many factors that influence your selections.
You need to figure as closely as possible what your expected AUW (all up weight, or flying weight) will be. Once you know this, you will know what the approximate wattage requirements are. Figure your ground clearance, and what size props you can run, then you will be able to figure your approximate Kv requirements. Motor, ESC, and battery selections are fairly simple after these initial steps.
I know it all sounds confusing right now, but once you get used to it, it really isn't rocket science.

A Watt meter is a MUST!

Good luck, and post a build thread once you get started.

Like I've said before, I've been building all kinds of models for 50 years on and off. And all the information you've been giving me is what I've expected. Yes, I will find clubs, get trainers first, work on simulators, etc. It's just that my Dad during the war was a top turret gunner on a 24, was shot down and was a POW for 15 months. I'm doing this inHis memory.I would never try to fly this 24 unless I was very confident that I could. If not, I would let an experienced pilot do it once, film it and maybe donate the plane in my Dad's name to a museum. A good friend who RC flys told me, there are very good builders who can't fly and good flyers who can't build. I'll find out who I am in the future.

Thanks for all your help,

Tally Ho

Dave

Thanks. Yes I did find Memphis Belle on this site who built a Don Smith B-24. A lot of his pictures are helping me with this build. His is gas powered. I'm just having fun, relaxing in the garage and this is quiet time therapy for me.

Tally Ho

Dave

Your response to my post seems kinda defensive. I certainly didn't mean to offend you, just trying to give sensible advice. I have seen too many times since i've been in this hobby where new pilots will bite off more than they can chew, not heeding others warnings, only to destroy a very nice model in the end.

This project will certainly be a very nice monument to your father's past experiences, good luck with it.
No reason you can't be a good builder AND a good pilot, you'll just have to try it and see for yourself.

Please, please, please, don't take my responses as defensive. I'm agreeing with you. I have no ego whatsoever. I have a motto in all my work, I'd rather do something right the first time rather than the second time. So if you see or sense anything that I might be doing wrong, please let me know. Even though I've been building for a long time, doing something for the first time will take me longer to do and like I said I'd rather do it right the first time. Hey, I like auto racing and Danica Patrick is fairly good in an Indy Car. But do you think she's not taking advice on driving a NASCAR stockcar as she is about to do? You're right, I don't ever want to see this model auger into the ground. So please give me all the advice you can. I also say that there are no stupid questions, only stupid answers.

Thanks in advance for all your help,

Tally Ho

Dave

I always say the same thing, no questions are stupid, after all, none of us were born knowing all of this .
As far as power requirements for your plane, if you can approximate the AUW, or flying weight, you can figure your power system pretty easily. Let's say for instance that the AUW will be 15 lbs. For decent power and scale type flight, I would aim for around 125 watts/lb, so that would be between 1800- 1900 watts. Since your plane is a twin, you should shoot for around 900-950 watts per motor.
You will then need to find out what diameter props will fit the plane. Once you know that info, you can then figure what Kv rating you will need and what voltage you will want to run.

I will give you an example:
I just finished building an E-flite Deuces Wild. It's a twin also, and the AUW is just North of 10 lbs. It's a sport plane, so I knew I wanted 1200-1400 watts for decent performance. The manufacturer states that a 13" prop will fit, but the ground clearance is much better with 12" props. The motors are counter-rotating, so I needed to see what pusher props were available in that size. I decided to run 12X6E props, so I'm running 2 650Kv motors on 5S, or 18.5 volts. I could have run 12X8E props and used 4S packs, but the higher voltage requires less current, which in turn, gives me better flight times, and the equipment stays cooler.

Hopefully this will help you with your setup, keep us posted and good luck.

72Vega provides good advice, though I think his power recommendation is a bit high. Then again,power requirement is always subjective. And what is scale flight, for that matter? Scale flight for Cub needsabout 50 watts/pound. Scale flight for anF15, maybe it is 150 watts per pound. The key is thatwatts/pound is the first approximation tool that we electric pilots use. If you looked at the link Iprovided you know that.

aeajr is correct in that power requirements are subjective. I do have a tendency to overpower a little, I would rather cut back on the throttle stick than have to build a whole system over because it was underpowered.
In reality, 80-100 watts/lb would probably be ok in your case, but again, depends on how you intend to fly it.

Ok, I have to admit, I confused the B24 with the B25, and was assuming you were setting up a twin. NOW, realizing my mistake, and the fact that you're building a quad motor plane, you will need to divide the targeted wattage requirements by 4, not 2. Everything else still applies though.
You will also need 4 speed controllers also, one for each motor. You will then have to decide how many batteries you want to run, 1, 2, or 4. You can run 1 large pack for all 4 motors, you can pair inboard and outboard motors on 1 pack/pair, or you can run 1 battery for each motor.
Alot of 4 motor builders like to run the inboard motors together, and the outbord motors together. That way, if you have a power failure on 1 pair, you still have motors on both wings that work. It will mainly depend on how much room you have for batteries, and where you plan on putting your access covers.
One of the biggest challenges to converting a fuel powered plane to electric is this very problem, as fuel planes aren't designed to have battery hatches. If there's room in the Nacells, you can put the batteries there, but will most likely have to go in the fuselage. Make sure you extend the motor to ESC wires, not recommended to extend the battery to ESC wires.

Sorry for my confusion .

There is a company that sells the B-24 in a nice looking foam. You might want to go to a place called ?? www.wowplanes.com ??
It will give you a lot of known power parts needed for a plane their size. It will help you on the cost of a BIG 4 engine.

Below is my first scratch foam 4 engine. 60 " wing span.

Dave

Are you using his plans that show gasoline or glow engines ? if yes. The plane WILL be needlessly heavy due to all the random vibration from the engines.

I am new to RTF flight but took my first solo yesterday and loved it, Even landed without mishap.

I have 2 other planes where the motor will not run. All of the other channels work except for the speed control. Is there a way to check the speed control? I've moved the engine to another port on the receiver and it does not help. Wanted to know if there is a way to check the engine without removing this and buying another.

This thread is about building a 4 motor B25 bomber. Is that what you are flying?

What motors are you using? What radio system?

I just finished reading Ed Anderson's e-book, Everything You Wanted to Know About Electric Flight, and wanted to give it a plug. Ed...just wanted you to know how much I appreciated this valuable primer on e-flight. It was of emmense help to me and countless others I am sure!

Brian

Brian,

Glad you found it useful.