firemanbill

Sounds ok, I would be a bit worried about the bent shaft motor though. These spin up some pretty high rpm and you maintain those rpm's the majority of the time. The weight difference should not matter too much. a little trim will balance that out if it is.

Are you going to run a separate rx pack or an external BEC? I would highly recommend one or the other.

A.T.A.C.

I bought a CC BEC, but I may not need it. The Phoenix 25 can handle 3 Amps and my understanding is that it is possible to use both Phoenix 25s without disabling the BEC on one of them. They should be able to handle 6 Amp together, which should be more than enough. I just need to find that 2 mm adapter, if it exists!
ATAC

firemanbill

If you have one I'd go ahead and use it. Any load you can take off the esc's stuck in that confined space in the wing will help with the heat.

Good luck on the adapter.

A.T.A.C.

That is a good point, but I think I will have adequate cooling on the ESCs. I am planning to modify your idea. Instead of having a porous material to cover over the ESCs, I will mount them to be flush with the wing surface. I will cover them, but I will cut the covering to expose all the FETs. Practically the ESC surface will be a part of the wing surface. I think that will provide more than enough cooling.

I still could not find a way to use my existing motors and batteries, but I am not giving up yet. In the mean time I will build the rest of the kit.

Thanks,

ATAC

Bill G

I've heard that it is not a problem to use BECs in parallel with some brands of ESCs, but I would not be sure about getting 6A total from two 3A BECs. Those of us who have crashed 4+ servo jets will tell you that the ESC must be out in the open, to have a chance with the internal BEC. I would have the entire fet side in the breeze as you stated. I still would want a switching BEC with 4 servos. If you're using DSM1 with slow-boot, absolutely use a switching BEC, as any glitch in the BEC suppy = crash. Servo brand matters too, as they do not all draw the same current.

firemanbill

Bill if you ar not counting me as one of those two make that number at least three.

That is how I lost my first Airliner... That is also how I almost lost my sedond one as you very well remember from the Cedar Creek fly in.

I have learned my lesson and now run a Medusa external BEC in mine.

Bill G

You're not by chance the one who made it into Flying Models magazine, with an Airliner that crashed due to overheated BECs in the ESCs? When my 262 went in, the ESCs had lost their shrink wrap, as it shrunk so tight that it tore. They work now, and must have just shut down from overheating. My new one has the ESCs in the fans, and a Park BEC.

firemanbill

I don't know Bill, When was that articel? If it was from SEFF 2007 then yeah, it was me.:o

A.T.A.C.

OK, I think you guys convinced me! I will use the CC BEC for the SAL. This plane is too beautiful, big and expensive to risk. Thanks for the sound advice. I just need to find the right adapters for the fans. -ATAC

firemanbill

Good choice!

Looking forward to seeing your finished product.

Bill G

Sounds about right, time wise. Bet it was yours. I think I have already twice notified people of their planes in FM, that weren't aware of it. I'll have to dig the picture up. It was torn up pretty good from the crash.

firemanbill

here is the pic of my aftermath...

A.T.A.C.

Ouch! It must have been a spectacular crash!!

firemanbill

LOL, Yeah it hurt real bad... Nosed it straight into the dirt from about 100 ft up. No control whatsoever. That happened in front of about 500 onlookers at SEFF in 2007

Just a plane though... I got another one to replace it. All the electronics survived, sans the esc's.

raido56

Hi ATAC,
I don't have the stock motors in my airliner but I do fly it with 2-4s 2550 25C packs. You will have to use the CC BEC and disable both of your onboard BEC's as the CC Phoenix 25 will not work with a 4s pack and the onboard BEC's. Below are the specs right from CC web site. I run 2-35 amp ESC's and a UBEC in my airliner and at WOT the readings on my watt meter are about 30 amps at 400 watts for each motor. So my total is about 60 amps at 800 watts. I run a 4s pack to each motor I do not parallel my packs. Both packs do fit in with no problem.

Volts w/BEC12.6 maxVolts NO BEC19.2 maxLipo Cells w/BEC3S maxLipo Cells NO BEC4S max

Keep em flying
raido56/ Herb

Bill G

Looked pretty similar Bill, but the dead grass was a dead giveaway. For a minute there I thought you had made the paper.

From Oct 08 FM:

firemanbill

Very similar. I thought I was going to get to ask for royalties there for a minute... bummer...

A.T.A.C.

Herb,

Thanks for the info. I will be using a CC BEC.

Which motors are you using? My main problem now is to find motors that would fit the stock fans and would work with 4s. I was planning to use Himax HA 2025s, but the shaft is 2 mm. The fans accept 2.3 mm.

Thanks again,

ATAC

Bill G

There's certainly no law that says that you need 4s for power. You can do the 3 blade rotor mod to reduce current, but there are a number of motors like the Don's Wicked that will give good performance on 3s.
For the 2025 series, the 2025-4200 will give good performance on 3s.

I'm not a fan of the CC BEC as it is simply another brick to be added to a plane. The small Park BECs are much lighter, and since you ACTUALLY get rated current, even a mere 2A will run a number of servos. I've never had a problem running 4 servos on them.

firemanbill

You don't need 4s...

I have the stock E-flite BL 400 motors in mine and run 2 2200mah 3s packs, 1 per motor.

You've seen it fly Bill, it does great... even on one motor!

Viper1957

Firemanbill, I feel your pain! Foam is great until something like this happens....

navy atc

Done in Delta livery

[media]http://www.youtube.com/watch?v=uMomDDmBPGc[/media]

and the light set up

http://www.youtube.com/watch?v=S_jjT7aA1yc

firemanbill

Nice!

navy atc

Hey Bill remember me? Im the firemans son with the bootprints...

firemanbill

Yeah, I remember you. How's it been going?