TLH101

My Feedback: (90)

Here's what was waiting for me when I got home today. Callie made them for me.

BigTeeEldorado

Terry,

I did not realize you were going electric. I am that much more interested because I am lost when it comes to electric. I am sure there is information still coming so I won't ask a bunch until I go back and read what you already posted.

Nice!!

70 ragtop

My Feedback: (24)

Nice!
going with the low Vis paint I see

Aros

Found this thread looking for 83" P-38 Lightnings. I am a fellow P-38aholic. Have been all of my life. I am anxious to purchase my first larger scale P-38. So far I've only had the foamie class. This will be my first kit. This will be the one I am snagging that my buddy and I will be making our winter project. He's the main builder and as an aero engineer I'm in good hands! I'm more of the paint/details/final touches and FLY guy, lol.

Legend Models 83" silver electric version. Unfortunately still waiting for product shots but their other kits seem decent enough, especially for my first. Can't wait! Boy you guys have some beautiful birds!

https://www.jb-hobbies.com/presta/wa...lightning.html

fvdriver

I am trying to decide if I want to get a JB hobbies P-38 or go the full monty and build a Ziroli. I am starting my research into the Ziroli kit. I have built an Art Johnson and planking the booms is a PITA!! so I am thinking about the complete fiberglass kit that Ziroli offers and a short kit from Precision Kit cutters. I would prefer to make it electric for reliability. Fowler flaps (of course) but I am not really into too many scale details.

So if any one has any suggestions or can direct me to a good build log, I know there are several, I would appreciate any input.

BigTeeEldorado

Here is another question for the forum.....In my build I am planning on using a feeder tank in the center Pod feeding 2 ounce tanks behind the firewalls. I have done this once before but not with this long of a span between the tanks which makes me a little uneasy. There is not a lot of room to redesign things so I am kind of looking for some validation before I proceed. What experience pro or con has anyone had with a setup like that. I did find another OS 40LA so it will be a pair of those I am feeding.

SWORDSN

My Feedback: (13)

The Ziroli would be right for a holic with $$$$$ ,but the JB Hobbies(same as VQ) would be a better first P38.I had a VQ and it was my first Warbird twin.

fvdriver

Not my first P-38. My first electric plane was an Art Johnson P-38 with retracts and fowler flaps. 22 sub C nicads for each motor. I used a belt drive reduction drive from Tom Hunt and Dewalt 14.4 volt drill motors. Turned 16" props about 5800 rpm. 6 minute flight time with no problem. Unfortunately JR radio went into fail safe during landing approach on 13th flight and it was unsalvageable. Also had a smaller foam P-38 but was disappointed in lack of flaps and retracts.
I know the Ziroli will be $$$$$. and probably too big for our field, but one can dream. Any good build logs on the VQ that get into problems/solutions etc?

70 ragtop

My Feedback: (24)

There's a few guys fly/flew the VQs, they're just not chiming in these days

IMHO, the VQ is a step down from an Art Johnson, BUT, you'll be flying in a few weeks vs months/years to build a Ziroli. I'm a big fan of electric twins, could swing some big scale props.

If you like to build, I would go Ziroli. If you want to go flying, VQ. Can always go VQ for short term, and build the Ziroli as a long term project

Couple VQ threads
https://rcwarbirds.com/Kit_Reviews/P-38/P38dual.htm
http://www.rcgroups.com/forums/showthread.php?t=537486
http://www.rcuniverse.com/forum/twin...vq-p-38-a.html

BigTeeEldorado

OK....picked up a RichModel p38 at the local swap meet today for 40 bucks. What I have read says it is a good flyer but it is best suited for electric. Soooo....I am kind of hoping I can get some help with the motor setup.

These are the Specs pulled from an E-Bay Listing of the model:

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TLH101

My Feedback: (90)

take a look at this page : http://www.theampeer.org/Glow2Electr...w2Electric.htm
Also lots of good electric info on R/C Groups.

70 ragtop

My Feedback: (24)

Tony
My first thought when looking at specs, is just use same stuff the foamies used. Can typically get spares pretty cheap, and since the FMS P-38 was discontinued, what spare parts are left are pretty cheap. Scale struts, props, spinners, motors and ESCs, all pretty cheap. If not, would at least give you an idea what size you need.
If you think the FMS spares might work for you, suggest reading thru the forums to learn what the issues were. You don't what to buy something if it was a know leak link on that plane

Check out Motion RC, Banana Hobby, or any of the other retailer who sold them. Can also search J Power P-38, about the same size
http://www.motionrc.com/fms-p-38-lig...p/#spare-parts
http://www.bananahobby.com/fms-6-ch-...ane-parts.html

BigTeeEldorado

Thanks guys, I appreciate the help. This is exactly what I hoped for. I have already spent hours trying to find meaningful information and a quick request here gets me pointed in the right direction instead of more fruitless searching. It's amazing the different searches I tried and never came across this stuff.

Using what I learned today I at least made a decision and got motors attached. I'll post more as I get time, it is going to be a busy week at work and I'm not sure how much time I'll have till later in the week.

Thanks again.

fvdriver

So Big-Tee I see you are in Vegas too. The motors do seem to be over kill but to check it out call Motrolfly and talk to them. I have several of their motors and they are really great, yes, more expensive. I talked to Castle Creations last year and they said the Motrolfly motors are the most efficient they have tested, by 3-5% Bring the 38 out to the Soaring club field to fly. Plenty of runway, we just made it longer this year and very low key. I would be glad to help, shoot me a pm.

BigTeeEldorado

I wondered when I might run into a neighbor on the forum!! I usually fly with Eldorado Valley Flyers and although I know of it, I have never been to the soaring field. We will definitely have to hook up. Post some google coordinates or something to help me find it and I might swing by on the weekend if I can.

fvdriver

Big Tee its too easy. Head out Charleston towards Red Rock. !/4 mile past the Gun club on the right you will see the gate and landing strip. I am usually out there on Sat. and Sunday about 8:30 or so because I work til midnight. I'll be the guy with the Spad.

BigTeeEldorado

I,m guessing SPAD is Simple Plastic Aircraft Design? I don't bash on ARF's so your safe.

sudstad

Hey Aros!
I remember following your posts when my son and I were flying Banana Hobby Lightnings!

I have one of the original VQ P-38's. It's a great arf. I only wish it had been designed for electric power back then! It's been rated the best flying Lightning by some pretty experienced flyers. Plus, you'll easily have it ready to fly for the Spring flying season.

SWORDSN

My Feedback: (13)

JB Hobbies has posted pictures of thier soon to arrive P38.Check it out.

fvdriver

Big Tee it is a Spad XIII built from a Monzano Lazer short kit. 52" ws. l had a few issues with the way the ribs were cut but otherwise it had great wood and very accurate cutting. Now to go to JB and see the photos

rvnrcer

My Feedback: (4)

If anyone is interested, I have a DA 50 that was set up by DA for reverse (left hand) rotation. I was going to use it in a Yellow P-38 but have decided to go electric. I will be listing it for sale on here and EBay. I installed it in a Top Flite Mustang and ran 2 tanks of gas through it but never flew plane with it. I also have 2 22x10 left hand rotation Biela carbon fiber props, 2 blade. I have a right hand rotation DA 50 purchased at the same time as the reverse one also, and would sell both as a set or just the reversed one. Let me know if you are interested.
Thanks, Keith

BigTeeEldorado

This is kind of long and if you need to shoe me off to another forum I understand.

Another question on the electric setup. I have had these two engines, 850Kv 42Amp G-Force, in a foamy version P38 fueled by two 4 cell 3300Mah 30-40C batteries. The batteries were wired in series so that they discharged evenly. I had the help of a fellow flier when we set that up who flies exclusively electric but is not available now to help.

That setup left a little to be desired in that flight times were short and on one occasion one of the two batteries got hot enough to melt the plastic wrap. As I get my head better wrapped around what all the factors represent and continue towards setting up this flyer, that hot battery and short flights bother me.

600 Watts is my goal power for this P38 based on 120 to 180 watts per pound on a 4 to 5 pound finish weight. My understanding says that the 42 amps is the maximum I want to make these motors use so a buffer of 10% puts my maximum amps at approx 38 amps. The motor then would like to use 562 Watts (Volts x Amps = Watts) at 14.8 Volts, 608 Watts at 16 Volts and varying watts in between as the voltage changes. Once paired with a battery I will then try different size props to hit the maximum amps or watts? Or Both?

Now the real question…..To choose a battery that covers the 38 amps with let’s say a 30% buffer I need my 30C 4 cell battery to have at least 1650 Mah. The math; (38 amps x 1.3 = 49.4 amps including buffer) 49.4 amps divided by the 30c rating = 1650 Mah to produce the 49.4 amps. This math and concept, if correct, will completely cover potential maximum draw from the motor and prop combination during normal operation with 1650 Mah battery...........right?

So why did a configuration with twice the Mah have short flights and get hot enough to melt plastic when I used it in the foamy P38? What am I not understanding???

Is it possible that by wiring the batteries in series and therefore the motors I am doubling the amp draw on each battery? The two batteries in series I know act as one 14.8 battery but did the Mah double because of two batteries in series or stay at 3300 like the voltage?

If I re-do the math…….38 amps x 2 motors = 76 amps total x 1.3 buffer = 98.8 amps total with 30% buffer. 98.8 amps divided by 30C rating = 3290 Mah .

If the Mah DID NOT double because of two batteries in series I would only have a 30% buffer at 3300 Mah and probably run two motors fine for a while but do I now have a marginal system that will run down the batteries quickly and overheat them because of a 99 amp draw on each battery? Eerily similar to what I have experienced.

This P38 has much MUCH higher wing loading than the previous foamy and electric is attractive if both motors run the same. I want the 600 watts for performance, I would be wasting the motors using 3 cells but the added weight of the 4 cell is creating a flying brick, which again will be OK if I can count on both motors and respectable flight times. I don’t know if I need extra Mah and the obligatory extra $$$ to wire them in series again or try wiring the motors not in series with the 3300 (or slightly smaller and lighter Mah) batteries and risk flying long enough for one to quit.

What say you all??? Most important to my question....Are my calculations being done correctly? Am I correlating the Watts, Volts, Amps and Mah correctly? Do I have the thought process correct or should I just shoot myself in the head and start over?

TLH101

My Feedback: (90)

First, series increases voltage. Parallel increases capacity (Mah). Your amp draw is based on the load (propeller) that the motor is turning. You CANNOT set up an electric system without some sort of power meter that will tell you your exact amp and voltage draw, unless, you are using an exact know set up.
This diagram shows a basic twin set-up. If you want to run 2 batteries, they should be parlleled before ESC. Or you can run 1 battery to each ESC. If you parallel the batteries, they should discharge evenly.

BigTeeEldorado

Terry thank you for helping. The graphics are awesome. My setup is planned to be in parallel (thank you for correcting me) with two ESCs. Do you have a graphic with that setup? I think I understand your comment and I have access to a meter to measure the setup but I am stuck on how to decide on the C rating and Mah to get appropriate batteries. I am trying NOT to guess if you get what I mean.

70 ragtop

My Feedback: (24)

Tony
Picture three that Terry posted shows both parallel and series connections. As he said, adding batteries in parallel will increase capacity. Batteries are connected together, which then supply either one ESC, or multiple ESCs
An important thing to remember when using parallel batteries is to make sure batteries are at the same charge state when you plug them in! I have seen battery connections melt, and wires get hot/start to melt if not. Think of worse case, plugging a fully charged battery together with a dead one. They will try and balance themselves out as fast as they can...which is bad

I would imagine you would have smoked the ESC or motor if you were actually wired up in series. Since your friend is an experienced electric flyer, I'm gong to assume they were in parallel. Parallel= battery reds connect to other battery red, blacks connect to blacks.

Refresh everyone's memory:
What model?
Weight and wingspan?

What prop do you want to fly? Large three blade, or two blade?
How do you want to fly? Speed demon, sport, or scale?