View Full Version : Goldburg Falcon III Help

12-03-2006, 01:09 PM
Hope I'm not re-asking a already posted question but here goes. And by the way, I just looked at the outside temp. It's 6.8 degrees out, too cold for anything ( well not anything ). I'm a 46 year old rookie and have a few questions. I am building a Goldburg Falcon III and would like to make it electric. The specs on the plan are:

56" wingspan

558 Sq" wing area

46.5" Length

4-4.5 lbs Flying wt.

.35-.45 recommended motor

What would be the best motor, esc, batteries, motor mount etc to use for this plane? Any and all advice would be greatly appreciated. With the weather I just as well be building something. Thanks for any help you learned folks can offer. DC

This may be the first of many rookie questions by me..................:D

12-03-2006, 05:36 PM
Hi there,

I have an old Falcon 56 MKII I will be electrifying this winter. I am planning on an AXI2826-12 motor with a Castle Creations or Jeti 45A controller and a 4S 3500-4000mA Lipo pack. It also depends a bit on what you want to do with it. I will be flying a bit of pattern as well as brushing up on my touch and goes. If you want a bit more performance, you might want to look into the E-Flight 40 motor. I have a bunch of the smaller E-Flights and they are great little motors. Sometimes, and it may seem a little counter-intuitive, but it is better to move down to a smaller size motor battery combo because the weight savings out weighs the increased power. I'm shooting for around 400W of power. Also, since you are building, try to lighten (mostly aft of the CG) as much as you can. Remember that these kits were designed to sustain the pounding of a partially balanced IC engine spinning a small prop very fast so they are quite over built. Weigh that against your flying skills (I cart-wheeled mine several times on take off once and it survived just fine. Pretty scary to see...). I personally build a bit more strength in, but lighten the parts that are driven by ease of construction and not engineering (large balsa planks and such). Watch that CG... The electric motors are lighter, but with the batteries they are pretty close to the engines weight wise but the layout is way different. The cool thing is that the CG doesn't change. When the gas tank drains, the model goes from nose heavy to tail heavy all in the same flight! Electrics are consistent in that regard, but you have to assume it will be tail heavy and try to get everything as far forward as possible. Another thing to consider is prop clearance. The electrics generally swing larger props (with increased efficiencies) but that can interfere with the ground depending on your flying surface.

Good luck with your project. Let us know how you progress...



Sky Sharkster
12-03-2006, 05:52 PM
Hello DC, Welcome to Wattflyer! The Goldberg Falcon is a great R/C model and should make a good introduction to R/C flying. I would suggest that you get in contact with a local R/C club and try some training flights with an instructor first. If there's no club nearby, at least arrange to have an experienced flyer to help you with the first trim flights.
If none of these options are available to you, it might be better to start with a foam electric ARF like the GWS E-Starter or Slow Stick. No matter how much advice, flight sim time or reading you do, there's always a few "unplanned" landings at first and the repairs will be much easier (and less expensive) with a foamie!
If you plan to go ahead with the Falcon, here's a few recommendations for equipment; First the motors.
E-Flite 46 B/L 670Kv
AXI 2826/10 http://www.nesail.com/detail.php?productID=3102
HIMAX HB 3630-0780 http://www.maxxprod.com/mpi/mpi-2601.html
Some of the speed controller recommendations are for a 40 amp B/L ESC but I believe you'd be better off with a 50a or greater capacity. My two favorite brands are Castle Creations http://www.castlecreations.com/
And Jeti Phasor http://www.hobby-lobby.com/speed-control.htm
ESC's are a whole subject unto themselves, here's a very good description of the most popular brands and their functions;
Batteries are complicated also, but generally you'll be using about 3S2P or 4S 3000-4000mAH LiPo's or 10 cell NiHM packs. For a handy reference to help with the electric "Lingo" go here; http://www.commonsenserc.com/page.php?page=battery_education.html&osCsid=b1e35125dc46690875e5c9f3269049a5
Common Sense is a supplier of reasonably-priced LiPo's, a "balancing" charger and hardware like connectors and adaptors.
Another essential item will be a Wattmeter, Astroflight has one of the best. http://www.srbatteries.com/efchrg.htm
On the "Builders Techniques" I've posted a sticky with many links for aerodynamics, building and covering tips, flight trimming, motor and battery basics, free online motor calcs, tools, etc. http://www.wattflyer.com/forums/showthread.php?t=12217
Good Luck!

12-03-2006, 10:55 PM
Thanks for the suggestions, I'm probably past the weight saving stage. The plane is built. All I have to do now is cover it and get the servos and linkages installed. I have a Tower Hobbies Trainer 40 that I finished a year or so ago. It hangs in my shop all ready to go but I've never flown it. I got the thought that electric would be simpler to start with because of the motor issues etc. That's why I decided to make the Falcon a electric. I do have 100's of hours using the RealFlight trainer on the computer. I know there's no substitute for real experience though. I've had to bug to get in to R/C planes since I was a kid but had no one to even help with the simplest questions. A friend of mine is a pilot for a commercial airline and he is helping me out but he knows nothing about electrics. I have been looking at the Rimfire motors and mounts. If I was to use one of them which one do you suppose would be the right one? Battery? Beings I am so new to all this I could use help at a very basic level. I WILL read the links that have been posted here and pick up as much information as I can. Once again thanks for the advice, it gives me a good place to start looking and learning. DC

Sky Sharkster
12-04-2006, 12:08 AM
Hello DC, I haven't seen any of the large Rimfire motors in use but the smaller ones seem to perform pretty well. I believe they are similar to the Himax brand in quality and performance. The model with the closest "specs" to the motors already listed would be the 35-36-1000 http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLWU2&P=0
For this motor the battery pack would be about the same as listed above. 8-10 cells of 2400mAH NiMh or 3S2P (or 4S) LiPoly of 4000mAH. If you decide to use NiMH or NiCad batteries, a good choice for a charger would be the Triton II, also available from Tower Hobbies.
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXMAJ0&P=MLThis charger will work with all the different battery types, but does not have a LiPo balancer.
Good Luck!

12-27-2006, 12:09 AM
DC - Check with AMA (modelaircraft.org) and find a club near you. There are bound to be some electric guys in the club. They'll help you a lot.
If you can't find any, just make a short trip here to the Dallas area. :)

jim antons
01-15-2007, 12:41 AM
15 yrs ago i converted an eagle to elec. geared astro 40, 18 nicads. floats, it flew (two minutes) on the columbia river...oregon . it was beautiful, but not worth the effort.now days it would be magnificent....jim