Conversion from .049 to electric (2024)

Sep 27, 2016, 07:33 PM

• #1

EBurkart3rd

Thread OP

Help!

Sep 28, 2016, 05:22 AM

• #2

scirocco

Scroll to the bottom of the page and you'll see a bunch of similar threads.

If they don't help, you need to tell us more about the model. Weight is important because it helps guide required power. Ready to fly with the Cox fitted would be a good start. Feasible max prop size is also critical, as if you can use a larger prop than the 5" an .049 runs you'll end up with a better electric system.

Sep 28, 2016, 08:51 AM

• #3

Mike Dubovsky

Sep 28, 2016, 10:51 AM

• #4

EBurkart3rd

Thread OP

Not gonna sell it. I'm going to give it to my father as a gift as it was the first plane we flew together almost 25 years ago........And you assumed wrong. its only a two channel plane (rudder, elevator). The engine ran independently.

Sep 28, 2016, 11:14 AM

• #5

EBurkart3rd

Thread OP

This what I have: it weighs 1 3/4 pounds. wingspan is 38 inches long. Fuse is 28 inches nose to tail. It flew once before with a cox .049 engine. Scale unknown.

Sep 28, 2016, 08:34 PM

• #6

scirocco

Fairly heavy for its size, but if it flew with an. 049 it can fly better as an electric model. A suitable electric motor will weigh similar to the. 049 and battery + speed control will be additional weight, so assume 2lb rtf.
For this style of model input power of 60W/lb would normally be enough but factoring in it having a bit higher wing loading (heavy for its size) I think 75W/lb or at least 150W input power would be a safe target. To handle 150W without overheating requires a motor around 50g minimum, which is convenient from a balance perspective given the .049 is about 60g.
Given the model weight and the power needed, a 3s battery from 1300 mAh will suit and should easily provide over 6 minutes flying with some throttle management. To manage weight I don't suggest starting with a bigger battery.
A 20A ESC will handle the peak current of about 15A
Actual motor choice to complete the system depends critically on the prop size that will fit. You didn't provide that info, but I'm going to assume an 8" prop will fit with enough ground clearance. If that's wrong, say so as it will require a higher Kv motor to work with a smaller diameter prop.

A good candidate motor and prop is the Turnigy Park 450-1200 (66g) and APC-E 8x6. This will use about 150W max, develop around 33oz static thrust and have ample pitch speed for your model's top speed.

Other motors of similar weight and similar Kv (1200 rpm/V) would work just as well. I wouldn't go under 1200 rpm/V unless you want to use a 9" prop or over 1500 rpm/V, and Kv above 1300 rpm/V would require a prop with less pitch or diameter.

You now need to set up the model on its wheels with the tail up in a flying attitude and measure from the prop shaft to the ground, then subtract 1" to get the feasible max prop radius

Sep 28, 2016, 09:59 PM

• #7

Mike Dubovsky

As far as weight goes back 40 years or so I used to fly 049 planes using a EK Logictrol brick and a 4 cell 450 mah nicd batt. One plane I used to fly with that equip weighed just under 2 pounds. With todays modern radios and electric motors I built the same plane a few years ago and it came in at 21 Oz. The setup was this Cobra motor:

http://innov8tivedesigns.com/parts/b...tors/c-2208-34

with an 18 amp Cobra speed control a 1300 mah 3S and a 7 X 6 APC E prop. It flew much better with that setup then my memories of the 049 setup. Probably due to a lot less weight. The plane in quesiton here probably ran a 225 mah battery with smaller servos and a lighter receiver, but I bet you will still be able to get it down to the same weight as the original. Even a 225 mah nicd weighed 2 oz which is the close to the same as a 1300 mah LiPo. Ligher receiver and servos might bring it in under that.

Sep 29, 2016, 11:32 AM

• #8

EBurkart3rd

Thread OP

Sep 29, 2016, 03:24 PM

• #9

scirocco

Don't spend a cent on a motor until you know the prop sizes you can use!

Sep 29, 2016, 06:05 PM

• #10

EBurkart3rd

Thread OP

Ok thanks!!

Oct 02, 2016, 06:41 PM

• #11

walter3rd

Oct 03, 2016, 08:16 AM

• #12

Mike Dubovsky

I see the original has a reed valve .049. You can better then dupilcate the performance of that engine using a 6 inch prop with this motor:

http://innov8tivedesigns.com/parts/b...-motor-kv-1570

It will turn a 6 X 4 prop faster on 3S than those old reed valves could turn a 6 X 3.

Prop chart for the above motor:

http://innov8tivedesigns.com/images/...4-40_Specs.htm

It is currently out of stock at Innov8tive but Randy at RC Dude shows it in stock:

http://www.rcdude.com/product-p/c-2204-40.htm