Flew an "Electric Stunter" today.

[Norm Faith Jr.]

I had the opportunity to fly an electric. During a short visit to the field today, I was asked by one of our club members, Jason Greer, to fly and evaluate his new (self design) electric “stunter.” BTW: he placed 1st. in Profile and 2nd in PA in this past weekend's "South Arkansas Stunt Championships" with this ship. First of all...by no means am I an "upper level flier," but I've been known to put in a few good scores here and there. After getting a little briefing as to the characteristics of the starting operation of the plane...Jason made the launch. The take-off was straight forward, line tension was instantaneous. After the regulation laps, I did the reverse wing-over and WOW! "My socks were blown off." I flew the rest of the pattern in a conservative fashion, but with attention to detail. As briefed...the motor run gave me the "three lap warning," stopped and made a smooth glide to a 38 landing. This airframe has only been flown about a dozen (respectively) times. Evaluation: Of all of the things that impressed me, was the "crispness’ of the "pull-outs." No bounce or jump. Most of all was the increase in line tension on the over-head eights, vertical eights, hour glass and the reverse wing-over. Jason attributes this effect to the "clock-wise" rotation of the propeller. This plane is a profile design; not small, I estimate between 650 and 700 sq. in. The constant concern of the "engine run" was there, but that was due to habit. The noise was different, even "strange."
Over and above the fact that this design was powered by an electric motor; I believe the design would perform well with a "gas burner." I suggested to Jason that he publish the prints. He did tell me that the design was influenced by a Bob Hunt design. Maybe Jason could give us some more "detailed information" of this "kick butt" profile.
Norm

[Jason Greer]

Norm,
Thanks again for flying it.  You are welcome to fly it any time.  I'm going to get 3 or 4 more batteries ordered for it soon so I can get some real practice time in on it.  The batteries I am using are 20 bucks a piece by the way. 

The side view is based very loosely off of Bob Hunt's Genesis Extreme.  Basically I found a picture of the Genesis and I did my best to model it's profile shape with a few changes to suit my own style.  The wing area is 650 sq in.  I used my own airfoil that is 1 7/8" thick root to tip.  The wing chord is constant.  The tail volume is 24% and is divided 50/50 between the elevator and stabilizer.  The tail moment arm is 19" from hingeline to hingeline. 

I've been very pleased with the power system in the model.  The Castle Creations ICE 50 speed control that I am using has the ability to log certain events during the flight.  I am logging rpm, current, voltage, % throttle used, and watts.  These values are logged 10 times/second.  According to the data, the top of the hourglass is the most power hungry segment of the pattern.  I am reaching 750 watts(over 1 horsepower) at that point. 

If anyone is interested in any other specifics of the model just let me know.

Jason

[SteveMoon]

Jason: Looks great. I'd really like to see some close up shots of the
engine mounting system. I'm designing some E Profiles myself and am
interested in seeing different ways for mounting the engines.

Thanks, Steve

[John KruziK]

Looks great!!  Where do you get $20 batteries.

[Jason Greer]

Steve,
The frontend is a core of 1/2" balsa with 1/16" balsa and 1/32" ply laminated to each side.  The 1/32" ply extends back to the wing high point.  The motor mount is 1/2"x3/8" maple epoxied directly to the 1/32" ply on each side.  An 1/8" light ply firewall is glued to the front to tie everything together.  The 1/32" ply spreads the motor loads throughout the entire front end.  This is the second model that I have rear mounted the motor and so far I havent had any trouble.  I have over 100 flights on my first electric model.  I have posted another thread in the electric forum that lists all of the components I am using on this model.  Just let me know if I was unclear on something or left something out.  Maybe the following pictures will help.

John,
The web address for the battery is:
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=8853

This is my first time using a battery from Hobby City.  I only have about 7 cycles on this pack.  We will see how it holds out long term. 

Jason

[Jason Greer]

One more picture of the complete model.

[Don Hutchinson AMA5402]

Hi Norm-
Well done. I need some fodder! I have to churn out a column for the next Stunt News. Who won the District 8 Profile award?? Who else was in the hunt?? I could also use 1 good photo. The actual contest report should go to James Mills if you want it in Stunt News. As you may guess if you read my column, I am not big on bunches of photos.
Don

[Rudy Taube]

Jason: Looks great. I'd really like to see some close up shots of the
engine mounting system. I'm designing some E Profiles myself and am
interested in seeing different ways for mounting the engines.

Thanks, Steve

Hi Steve,

In addition to Jason's neat install, you may want to look at a few others here on SH:

    This is Tim Stagg's excellent P-47 profile ECL. He hid the ESC and the Timer in the outboard cowl in his beautiful install. :-)

         http://stunthanger.com/smf/index.php?topic=17616.0

   This is Crist Rigotti's outstanding ECL profile. It's page 3 of his detailed 4 page thread. The rear bearing MM is NOT needed (it was an experiment only), you only need the front mount. His MM is KIS, solid, easy to make, light, inexpensive, and looks great. :-)

         http://stunthanger.com/smf/index.php?topic=11458.100

These are two of the best profile ECL installs I have seen. There are many more. I have a large collection of install photos, if you are interested send me a PM.

If anyone is interested in getting into ECL, a profile is very easy to convert, or do new with Electric power.

Jason,

As others have said: "Well Done!"  ....... Welcome to the wonderful world of ECL 

Regards,