Banshee balance point

[Tim Wescott]

What's the correct CG on a Banshee.

[Paul Taylor]

Hey Tim
If I remember right it depends on what engine your using. I have one in the box and can check when I get home in a few days. But maybe someone else will chime in.
I remember someone telling me there is a small note in the box. Something about you have to cut a inch off the nose if your using a Fox 35. Some people say to move the wing forward. I hate to say it but do a search here or on SSW and you may find your answer.  Good luck and be sure to show your work.   

[Randy Cuberly]

Tim,
Actually the correct CG will be basically the same no matter what engine you use.
I think what Paul was trying to say is that the Banshee has a very long nose and was designed to balance with a light engine like the Fox 35.
I you use a heavier engine you will want to shorten the nose or lengthen the tail or a combination of both.
The correct CG will likely fall between 15 to 18 % of the MAC since the Banshee has a relatively small Stab/Elevator area.
The exact CG always depends somewhat on the preference of the pilot.  Some prefer quicker response and some prefer more stability.
 The numbers above are a good place to start.

Randy Cuberly

[Tim Wescott]

It came to me already built.  I was more wondering what the kit says.

It balances about 1/2" ahead of the spar, which seems a pretty good starting point to me.

[Gary Mondry]

The kit plans (I'm looking at them now) show it about 1/16 aft of the front edge of the spar, which puts it about 2 15/16 aft of the leading edge.

Gary

[Paul Taylor]

Yea what Randy said. 

[Jim Thomerson]

I translate what Randy said as 1 5/8 inches from the leading edge, and that is where I would put the CG.

[john e. holliday]

Anyway you do it, remember a nose heavy plane will live to fly again.  A tail heavy plane may not.

[Mike Lauerman]

Anyway you do it, remember a nose heavy plane will live to fly again.  A tail heavy plane may not.

Absolutely words to live by!

[Dave_Trible]

I would put it where the designer intended for it to be.  If that feels too sensitive for you then narrow your handle line spacing-don't de-tune the airplane.

Dave

[MarcusCordeiro]

Anyway you do it, remember a nose heavy plane will live to fly again.  A tail heavy plane may not.

X2!!

Marcus

[dirty dan]

What's the correct CG on a Banshee.

I've seen this movie before. Pass...

Dan

[Randy Powell]

The Banshee in question has a 1" shortened nose and a 2" lengthened tail.

22% is the answer.

[Tim Wescott]

I thought 42 was the answer!!

I'm mildly astonished to hear that the tail is lengthened -- that thing must have been exceedingly short-coupled out of the box, and as it is it still has 1-1/4 ounce of lead in the tail, and may need more.

[wwwarbird]

 OMG this is painful to watch. It's a Banshee fer cryin' out loud. Hook up the lines, fly it, and just trim it to your preference from there.

[Tim Wescott]

OMG this is painful to watch. It's a Banshee fer cryin' out loud. Hook up the lines, fly it, and just trim it to your preference from there.

Look, I was just looking for a decent starting point that would most likely not result in an instant crash.  I just never read the fine print:

Warning: Contents illustrated on label may not reflect the actual contents of the can.  This can may be full of worms.  Regardless of how simple you think your life may be after you open this can, you may still find yourself presented with a bunch of worms crawling around.  Open at your own risk

[wwwarbird]

 C'mon Tim, I'm just saying that the Banshee is a very simple design to set up and get flying. Certainly you must have enough experience to give yourself a baseline starting point that wouldn't result in an "instant crash".

[Randy Cuberly]

Look, I was just looking for a decent starting point that would most likely not result in an instant crash.  I just never read the fine print:

Warning: Contents illustrated on label may not reflect the actual contents of the can.  This can may be full of worms.  Regardless of how simple you think your life may be after you open this can, you may still find yourself presented with a bunch of worms crawling around.  Open at your own risk

Tm,
Not knowing how experienced a flier you really are I gave you a conservative number 15 to 18 % MAC as a starting place.  It is the best answer.

It will probably fly with the CG at 25 to 30 % MAC but you won't like it.

Designs with small relative Stab/elevator areas need a fairly forward CG and a little more control throw to achieve stability and still have reasonable maneuvering ability.

If the fuselage has been extended to the rear that adds some control authority but not necessarily additional stability.

I do agree that the thing will fly with any of the answers given...so just fly it and see.

I do not agree that making the handle less sensitive is a substitute for a correct CG, unless of course you like airplanes that hunt.
I prefer my hounds for that!     

Randy Cuberly

[Tim Wescott]

I read Dave's post to mean that I should get the plane set up right, then adjust the handle to suit me.

I'm planning on moving the CG around until I get some combination of grooving nicely and decent turning, while hopefully not falling out of the sky when the engine stops.  Then, if necessary, I'll change the spacing of the lines on the handle.

[Dave_Trible]

Tim I think that's the best approach.  Usually by the time a design is in kit form (like 30 years now?) or published/developed by an experienced pilot the CG for best flying is figured out, seldom by calculation but by flight time.  In the days before we really understood adjustable line spaced handles we had our Ez Just at 5" or Hot Rock at 4", our 3" Veco crank and nose weight to tame the wirey beast. Imagine putting and extra 1/2 ounce of clay on the nose of your chuckie (hand launch glider to some)-it will head straight for the dirt.  Adding too much nose weight can cause more problems than it solves for a stunt ship. For sport, racing, carrier or whatever it won't matter as much. Realized or not you'll need to hold a touch of up to keep the plane level (down inverted).  Greater control deflection will be required for turns which slows the ship.  Also if you can think in terms of time-to-turn married to angles-of-deflection you'll see the light.  When you see an airplane appear to gallop when ending a square corner it's usually the nose heavy machine where the pilot can't make the corner and return to neutral fast enough so he overshoots the turn.
The nose heavy machine also changes the lead out setting as that chases the CG.  It pulls like bear in level flight but falls out vertically as the weight works against you.  You might get awkward wiggles and yaw problems. Egg-shaped rounds are a sure bet.  When the power cuts if the ship immediately dives rather than slowly winds down then you got nose heavy.
If worried about an untried new airplane just close the handle spacing way down- say 3" and open it back up on the first few flights to where you like it.
Had an extra minute here so thought I'd expand the thought some. Good Luck!

Dave

[Tim Wescott]

The Banshee in question has a 1" shortened nose and a 2" lengthened tail.

22% is the answer.

And 2-1/4 ounces of lead in the tail!!!  I knew about the first 1-1/4, but when I went to dig it out (the plane is tail heavy -- it just kinda stops in the air when the engine runs out) I found the other ounce behind the first one.  Oi vey!

It's getting a weight box so's I can fiddle.  I think I could make the lid out of steel and be OK, because I'm pretty sure that I'm not going to be taking out the whole ton thing.

[Derek Barry]

The nose and tail length are irrelevant. Balance it at the high point of the wing, set the handle to a conservative setting and fly it. If the plane is balanced it will fly.

Derek

[Steve Fitton]

Put vortex generators on it.  That will balance it.

[Dennis Moritz]

Every now and then I see one of these fly well. Stock. I saw one with the original long nose win Intermediate at Brodak one year. A ratty bird at that. Not that easy since many Intermediate fliers at the Big B should have stepped up to Advanced. Maybe there was a Fox 35 in the nose. Flown without a muffler. An engine nearly 2 ounces lighter than more modern power.

[Randy Powell]

Tim,

It had a ton of weight in the tail because it had a 12oz engine in the nose.

[Steve_Drake]

I am new to control line stunt so all info is good info. My banshee: wing moved forward 1"1/2 increased stab size balances just in front of the spar. Been a good trainer for me. Flew the full pattern in the last two contests last year.

My moma told me if you don't have anything nice to say keep your hands off the keyboard. Or you could just turn the channel if what your watching is to painfull.

Steve