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Li'l Wizard Stunt

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Li'l Wizard Stunt

Post  Cribbs74 on Mon Dec 31, 2012 11:42 pm

I knocked out the buildup of my son's Li'l Wizard. I chopped about 3/4" of the nose and added some extra trailing edge. I didn't want him to get bored so hopefully he can do a few stunts with it.

Now that I knocked off the nose some how do I go about figuring out where the CG is?

https://i.imgur.com/SyjBy.jpg


https://i.imgur.com/5oobX.jpg
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Re: Li'l Wizard Stunt

Post  pkrankow on Tue Jan 01, 2013 12:41 am

Grab the engine and fasten it on with a pushpin. Find the balance point in this configuration and mark it. If it is at 20% of the wing area is in front of the CG then you should be OK. If it is much further back you are tail heavy. Naturally you will need to fly and trim, but it shouldn't be too far off.

Shortening the nose of the lil Wizard is all it should have taken to make it come alive for stunt.

Phil
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Re: Li'l Wizard Stunt

Post  Cribbs74 on Tue Jan 01, 2013 12:50 am

Thanks Phil,

Yeah, I remembered the nose needed to be shortened, but I figured a little more wing area couldn't hurt. I will mount the motor and check where she balances at.

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Re: Li'l Wizard Stunt

Post  RknRusty on Tue Jan 01, 2013 2:24 am

From my bad experiences with maidening unknown models, all I can add is to only use a SIP of fuel. You can probably hang on for 2 or 3 laps and then you'll know which way to go with the CG. If it's too easy to fly(nose heavy) or too unstable(tail heavy), adjust accordingly until it's right on the edge of twitchy. That's your max stunt setting.

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Re: Li'l Wizard Stunt

Post  Cribbs74 on Fri Feb 08, 2013 2:50 pm

[quote="RknRusty"]From my bad experiences with maidening unknown models, all I can add is to only use a SIP of fuel. You can probably hang on for 2 or 3 laps and then you'll know which way to go with the CG. If it's too easy to fly(nose heavy) or too unstable(tail heavy), adjust accordingly until it's right on the edge of twitchy. That's your max stunt setting.[/quote

Looks like that's what I am gonna have to do Rusty.

Here it is, almost done.

https://i.imgur.com/4jo5VUo.jpg

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Re: Li'l Wizard Stunt

Post  Sig Skyray on Thu Apr 09, 2015 1:34 pm

My son will be building a Brodak Lil Wizard soon, kit should arrive today.

By comparing your photos with the Brodak Lil' Wizard it looks like your nose is 3" shorter at least.  You only removed 3/4" ?


I hear these are very nose heavy and I'd love to make the plane more maneuverable.

This may be a very novice question but... how does one move the CG forward or backward?  Adding weight to the fuselage?

Thank you.  Greg
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Re: Li'l Wizard Stunt

Post  rsv1cox on Thu Apr 09, 2015 4:11 pm

I love the new look Wizard Ron. The increased wing area makes it. Looks like the trailing edge has a little "up" in it or does it flow with the plane of the wing? Are those wing skids functional? Whats the finish? Too many questions? Smile

Bob
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Re: Li'l Wizard Stunt

Post  Cribbs74 on Thu Apr 09, 2015 5:08 pm

Sig Skyray wrote:My son will be building a Brodak Lil Wizard soon, kit should arrive today.

By comparing your photos with the Brodak Lil' Wizard it looks like your nose is 3" shorter at least.  You only removed 3/4" ?


I hear these are very nose heavy and I'd love to make the plane more maneuverable.

This may be a very novice question but... how does one move the CG forward or backward?  Adding weight to the fuselage?

Thank you.  Greg

Greg,

This was built from an original kit and was designed around a Babe Bee engine. As you can see the Brodak version was designed for a beam mount using a front rotary engine. Generally the TD's and Brodak .049's are lighter so they require a longer nose to balance.

To answer your second question there are many ways to shift the CG and adding weight is usually the last thing you would want to do.

Normally you would either cut the nose, move the wing location, shorten the tail or find an engine that weighs more or less. Doing these things will shift the CG front or back.

Ron

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Re: Li'l Wizard Stunt

Post  Cribbs74 on Thu Apr 09, 2015 5:14 pm

rsv1cox wrote:I love the new look Wizard Ron.  The increased wing area makes it.  Looks like the trailing edge has a little "up" in it or does it flow with the plane of the wing?  Are those wing skids functional?  Whats the finish?  Too many questions? Smile

Bob

Bob,

The wing has an airfoil sanded into it from the factory so it makes it appear that the TE points up. It's actually level with the bottom of the wing which is flat.

The little tips are not actually skids and have no function. They are ply if I recall correctly and were added for decoration I assume. They inboard one acts as a leadout guide.

Paint is Krylon with TF clear over it. Not my best work, but it's a trainer so....
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Re: Li'l Wizard Stunt

Post  rsv1cox on Thu Apr 09, 2015 5:58 pm

That's my combo of choice too Ron. Did you use a primer or sanding sealer?
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Re: Li'l Wizard Stunt

Post  JPvelo on Thu Apr 09, 2015 6:18 pm

Ron,

Cool plane. I like the idea of making it more versatile. My first plane was a Lil' Wizard with a black widow and I outgrew it fast.

To locate the proper c.g. Point you want 20% of the average chord. Since you have constant taper from root to tip the average chord will be the halfway point of one of the wing panels. Measure the chord at that halfway point and calculate 20% of that length. Go back that far from the leading edge and that is where you want your c.g.

Jim
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Re: Li'l Wizard Stunt

Post  pkrankow on Thu Apr 09, 2015 6:59 pm

Paint almost always moves the CG towards the back, simply because there is more area to paint behind the CG due to the heavy engine.

Rattle can paint is heavier than dope, so if you choose that route be careful and try to stay with 1 coat after a well-sanded series if primer coats.

Phil
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Re: Li'l Wizard Stunt

Post  Cribbs74 on Thu Apr 09, 2015 7:40 pm

Funny, I am getting more tips and kudos now than when I posted this over a year ago. lol!

It's been finished, flown, crashed, flown many times since then. I only flew it once just to check it out then passed the handle to my son. If I were to do it over again I would probably have done it without the wing extensions.

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Re: Li'l Wizard Stunt

Post  Sig Skyray on Thu Apr 09, 2015 9:27 pm

Cribbs74 wrote:Funny, I am getting more tips and kudos now than when I posted this over a year ago.  lol!

It's been finished, flown, crashed, flown many times since then. I only flew it once just to check it out then passed the handle to my son. If I were to do it over again I would probably have done it without the wing extensions.

Our kit came today and I'm glad you mentioned not adding in the wing extensions Ron because just before reading that I decided it was a good idea.  I found ample balsa here in another box and was ready to go for it.  I will be shortening the nose. Thanks for the update.

BTW, my Carl Goldberg Lil' Wizard kit from the 70's used a lead rod for outboard wing weight. That bar was about 1/8" by 3" long, no kidding... it was big. This kit says to glue two pennies to the underside of the outboard wing tip. Very curious to see how this will model will compare.

Greg
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Re: Li'l Wizard Stunt

Post  Cribbs74 on Thu Apr 09, 2015 10:05 pm

Greg,

It's really up to you, It's just it didn't help anything. I think Phil was right about that point.

The Brodak Wiz, a Medallion and a properly plumbed hard tank would make an excellent trainer.

Please post pictures of your progess.

Ron
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Re: Li'l Wizard Stunt

Post  RknRusty on Thu Apr 09, 2015 11:39 pm

RknRusty wrote:From my bad experiences with maidening unknown models, all I can add is to only use a SIP of fuel. You can probably hang on for 2 or 3 laps and then you'll know which way to go with the CG. If it's too easy to fly(nose heavy) or too unstable(tail heavy), adjust accordingly until it's right on the edge of twitchy. That's your max stunt setting.
I should add this: If you aren't sure if it's just a little bit nose heavy, when it shuts off flying level, add no input, just hold neutral. If it immediately sinks, requiring UP input, then lighten the nose some more. Of course if it went up at shutoff, requiring DOWN input. your plane is  _____________
Fill in the blank.
Rusty

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Re: Li'l Wizard Stunt

Post  pkrankow on Fri Apr 10, 2015 8:19 am

RknRusty wrote:
RknRusty wrote:From my bad experiences with maidening unknown models, all I can add is to only use a SIP of fuel. You can probably hang on for 2 or 3 laps and then you'll know which way to go with the CG. If it's too easy to fly(nose heavy) or too unstable(tail heavy), adjust accordingly until it's right on the edge of twitchy. That's your max stunt setting.
I should add this: If you aren't sure if it's just a little bit nose heavy, when it shuts off flying level, add no input, just hold neutral. If it immediately sinks, requiring UP input, then lighten the nose some more. Of course if it went up at shutoff, requiring DOWN input. your plane is  _____________
Fill in the blank.
Rusty

Nose heavy fly poorly, tail heavy fly once?

Phil
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