Great Planes Ryan STA 120 to electrics

[roscoe]

Tried a search, with no results. Just lucked into a NIB kit (ARF), and am planning an electric conversion. Has anyone tried it, and what was your set-up. I am planning a 6S2P A123 battery, with a MaxCim geared 4-1.
Any suggestions will be appreciated.

[jrb]

This one: http://www.greatplanes.com/discontinued/gpma1345.html , http://www.greatplanes.com/reviews/gpma1345-man.html ?

I think 6S is light; I use 6S in my .40/.50 conversions; my 1/4 Cub is 10S2P: http://www.rcgroups.com/forums/showthread.php?t=752795 .

[Goinav8n]

I have a Ryan STA sig that has been converted with a Kontronics fun 600 4:1 swinging a 15x10 prop with 6s2p batteries. It had mega power and was not light weight. 7s should be good with the A-123 deoending on the motor you choose.

Jeff

[Mark Wolf]

I converted this kit about 10 years ago, before Lipos or A123's. Way back when, mine flew on ~1000 watts from 36 nicad cells through a brushed Astroflight 60 and a Modelairtech belt drive. It flew nicely then even with only 1000 watts and flying weight of ~15 pounds, just not much duration. Someday I'll pull it out of mothballs and redo it with a modern power system.

[Sabrejock]

PCalc gives the 6s2p 4:1 'Y' wind 15x12 APC about 70 mph pitch speed at only 37A for duration WOT of over 7 mins. So it should fly quite well. But there's lots of room for more Amps if you need them.

A 3.5 GB gives better performance and still over 5 mins WOT. Tex.

[Lenny970]

I converted one several years ago and it's still flying. It was originally setup on 30 nimh cells and I swapped it over to a 10S lipo setup about two years ago.

Really a sweet model. Mine's flying at about 13 pounds with 2KW of power, but it flies nicely at 1/2 throttle.

Sure looks great in the air!

Lenny

[Yak18]

This may sound dumb but why not just find a similar size project that someone has done and copy their motor/esc/battery set up? That's what I do and it's working great so far.

BTW I have the STM version that I will be converting 3 projects down the road. Please make a thread so I can copy you!

[CUBANO8]

http://www.rcgroups.com/forums/showthread.php?t=763480

[rogerchr]

http://www.rcgroups.com/forums/showthread.php?t=763480

Hey C8 - long time no hear from. Have you worked on that BT Corsair?

[flieslikeabeagle]

I've run into this same problem with most of my models - what should I use to power this thing?
why not just find a similar size project that someone has done and copy their motor/esc/battery set up?

If the other similar project has about the same wing area and about the same overall weight, and you're happy with the way the other one flies, then this method certainly works.

On the downside, this method doesn't ensure you're getting the best possible performance or performance per dollar - for all you know, the setup you're copying may not be a particularly efficient one, or it may use unnecessarily expensive components. For instance, it might use too small a propeller (low efficiency) and compensate by pouring extra power through the motor - it will still fly fine, but would fly better with a different motor and bigger propeller.

Because of this, I rarely copy another persons setup until I'm sure I can't do any better, either performance or budget wise. So how can one be sure?

One way is to use a suitable calculator program. I wrote WebOCalc, a (free) calculator program for this purpose. You plug in your models weight, wing dimensions, and desired flight characteristics, and WebOCalc spits out enough information to let you pick motor, prop, and battery. I've been using it on all my models for a couple of years now, and it's worked for me every time.

You can find WebOCalc on my RCG website, http://flbeagle.rchomepage.com . Click "Software", then "WebOCalc".

I'd run the Ryan STA 120 through WebOCalc for you myself, but I'm in a rush...if you have any trouble trying it, I'd be glad to help out later, when I'm done with work.

-Flieslikeabeagle