Over Reactive Magician

[Allen Eshleman]

From cold Pennsylvnia,      39 degrees this morning.

I have a Magician, powered by a Fox 35.  It flies well but over reacts with the slightest touch of the handle.   How could I remedy this situation?

[Allan Perret]

Move elevator pushrod to a lower (further from the pivot point) hole in the horn.

Reduce you line spacing at the handle. 
If your handle is not adjustable, I recommend you get one that is.  Prefably a hard point.  Tom Morris sells one for $20.

[Chuck Feldman]

OK let me be the first to respond. It may be tail heavy. ( Most likely) Check your handle. If you close the line spacing it will become less sensitive  and vice versa.

Chuck

[Randy Ryan]

OK let me be the first to respond. It may be tail heavy. ( Most likely) Check your handle. If you close the line spacing it will become less sensitive  and vice versa.

Chuck

Beat me to it. Yes, without seeing it I would also say tail heavy but elevator deflection may also be contributing.

[Ward Van Duzer]

Use inner hole on Bellcrank. (if accessable!)

Use outer hole on elev. horn or use bigger horn.

And all that stuff about the handle too...


W.










 

[Tim Wescott]

If it's tail heavy then when the engine cuts off it'll tend to slow down.  In extreme cases, it'll seem to want to stop in the air and float down unless you give it a lot of down elevator.  It'll also (and this is harder to tell) react more to gusts and turbulence.

Where's your CG?

[Derek Barry]

Make it balance just aft of the high point of the wing, maybe a half inch at most. If it is still too twitchy close down the handle spacing some, 1/8 inch at a time, moving both the up and down line towards the center. If this does not help or if you do not have an adjustable handle you may have the controls set up too quick.

Derek

[Allen Eshleman]

How, where and what do some of you use to attach weight to the front of a profile plane?

[Paul Smith]

Try taking some weight off the back end.

I read the suggestions and the only one I agree with is tail heavy.  Excessive control movement can make a stall more likely, but it won't create instability.

[ChrisSarnowski]

How, where and what do some of you use to attach weight to the front of a profile plane?

One way to do it is to use a heavier muffler on the engine. If you are using a tongue muffler, switch to to regular Fox 35 muffler.

You can use stick-on weights from Brodak. They might come off after a while, so keep an eye on them. You can glue or bolt them on.

http://brodak.com/stick-on-weights.html

Other options include a Brass spinner nut (Harry Higley Heavy Hub) or a weighted washer. I forget who makes the washers.

-Chris

ps. I stick them (stick on weights) on the nose opposite of the fuel tank.

[Dave_Trible]

I would experiment with stick on (or taped. wired) weights until I had the amount I wanted.  Then bore holes on the bottom between the ply doublers and bury lead fishing sinkers to that weight in the holes with epoxy.  If you wish you can fill and paint over the holes.

Dave

Be sure to follow the guidelines Derek mentioned about the CG.  When it's balanced at that spot don't overdo the nose weight.  Start closing down the handle spacing.  Regardless of the cause these steps should make it fly better for you.
Second addendum; I pulled out my old Magician kit plans and the designer (Jim Silhavy) put the CG just 1 1/4" behind the leading edge.  This is MUCH further forward than we would do it nowadays but then he likely was using the old 5" EZ Just handle.

[John Stiles]

How, where and what do some of you use to attach weight to the front of a profile plane?

Not a profile, but.......Brass spinner..muffler

[john e. holliday]

Is the Magician built without movable flaps or does it have flaps?

[Joseph Lijoi]

I would experiment with stick on (or taped. wired) weights until I had the amount I wanted.  Then bore holes on the bottom between the ply doublers and bury lead fishing sinkers to that weight in the holes with epoxy.  If you wish you can fill and paint over the holes.

Dave

Be sure to follow the guidelines Derek mentioned about the CG.  When it's balanced at that spot don't overdo the nose weight.  Start closing down the handle spacing.  Regardless of the cause these steps should make it fly better for you.
Second addendum; I pulled out my old Magician kit plans and the designer (Jim Silhavy) put the CG just 1 1/4" behind the leading edge.  This is MUCH further forward than we would do it nowadays but then he likely was using the old 5" EZ Just handle.

Not necessarily.  Attached is hopefully a PDF of Bench Trimming A Stunt Ship by Brett Buck.  If it isn't attached Google Bench Trimming A Stunt Ship and you will find it.

This is a very helpful document that has saved me a lot of grief.  Thanks to Brett on this.  Follow these instructions. 

All due respect to Derek, I suspect half an inch aft of the high point is way to far back for the average guy.  1 1/4" behind the leading edge per the plans that you mention by the designer sounds like it is about 15% of the MAC, assuming the wing chord is what I think it is, which is close to what is recomended in the article. 

You can melt lead with a soldering iron into the backplate of your Fox to get to the recommended CG in the article.  JB Weld this and/or make a tin cover that is held on with the backplate screws.

[Brett Buck]

Not necessarily.  Attached is hopefully a PDF of Bench Trimming A Stunt Ship by Brett Buck.  If it isn't attached Google Bench Trimming A Stunt Ship and you will find it.

This is a very helpful document that has saved me a lot of grief.  Thanks to Brett on this.  Follow these instructions. 

All due respect to Derek, I suspect half an inch aft of the high point is way to far back for the average guy.  1 1/4" behind the leading edge per the plans that you mention by the designer sounds like it is about 15% of the MAC, assuming the wing chord is what I think it is, which is close to what is recomended in the article. 

You can melt lead with a soldering iron into the backplate of your Fox to get to the recommended CG in the article.  JB Weld this and/or make a tin cover that is held on with the backplate screws.

  Everybody is quite welcome to the .PDF, of course, and there is another thing that might be useful here:

http://stunthanger.com/smf/index.php?topic=7798.0

   Again, with all due respect to Derek, and bearing in mind that I don't have the plans in front of me -  1/2" behind the high point sounds pretty sporty. Might get away with that on a Impact, not so likely with a teeny-tail Magician, even with movable flap. I am not a fan of excess forward CG, but 1.5" sounds more like it to me, too. It should be around 18% of MGC with movable flaps, or 15% with elevator-only. Once you get it close, you can experiment with moving it back *teeny bits at a time*, like 1/16" at a time and see what happens. The range of acceptable CGs will be *very very small* as is typical with these sorts of airplanes with small tail volume. Move it more than that, and you might jump from too sluggish to too twitchy in one step.

    Weight can be added by putting on Prather nose weights on the propellor shaft, by melting lead into the backplate, stick-on weights, whatever. Once you get it in the right area, then you can make it look neat. Don't be dissuaded by the amount of weight you are adding, if it needs 3 oz, so be it, there is no alternative. One of my local flying buddies built a Barnstormer that took something like **6 OZ** of nose weight. He was really upset with the weight it added, so he took it off. He managed to keep it in the air but with the CG off by **several inches** he eventually decided that heavy and balanced right was better than light and uncontrollable. There is no trick that will make it fly right if the CG is not right.

   Brett

[Steve Helmick]

I would certainly check for lumpy controls while under tension, if the CG is not pretty close to that 1.5" spec.  Steve

[Allen Eshleman]

Thanks guys,

        Yep, I still use an E-Z just handle.  I am going to add some weight with wire or tape to the front and see what happens.  The engine is a Fox 35 w/o muffler.  It's an old one.  I think I have another muffler here but not sure how I would attach it.

Thanks again,

I'll post again when I get to fly and get it worked out.

[steven yampolsky]

        Yep, I still use an E-Z just handle.  I am going to add some weight with wire or tape to the front and see what happens.  The engine is a Fox 35 w/o muffler.  It's an old one.  I think I have another muffler here but not sure how I would attach it.

EZ-Just handle has a 4" spacing. I suspect the bellcrank on your model is most likely 3" or maybe even smaller. I am pretty sure your problem is in the handle. Before you make any other changes, I suggest you make sure the line spacing at the handle is closer to the bellcrank size, ie 3".  This needs to be done before you start adding weights. Adding weight is the last thing you want to do to a model.

[Bob Reeves]

Thousand of Magicians, Twisters etc. have been flown with a 3 inch bellcrank and EasyAdjust handle. I know the modern thinking but it will work fine when the CG is right and make sure the controls are not sticking.

[Brett Buck]

Thousand of Magicians, Twisters etc. have been flown with a 3 inch bellcrank and EasyAdjust handle. I know the modern thinking but it will work fine when the CG is right and make sure the controls are not sticking.

   If it is *only* a matter of control sensitivity then it is just a matter of either altering the handle or learning to live with it (which is indeed what we used to do). If it's a matter of the CG being misplaced, it will have many other ill effects in addition to being twitchy, so it's worth trying to fix it.

   One of the classic mistakes from the good old days was to use a giant handle with a teeny bellcrank and fast ratios, and then load on noseweight until you could fly it. I think a little attention to detail can avoid that one, if one wants to.

   brett

[Randy Cuberly]

I,ve never understood why so many people want to address problems with band-aids instead of fixing the problem!

Put the CG where it belongs...

Randy Cuberly

[Allen Eshleman]

Well,  I finally flew the Magician.  I added some weight on the front, oiled the controls,  and I also used a biased handle.  Wow! a totally different Magician - fun to fly, not over re-acative.  I flew three flights.  The first on was only loops, fine, a little lean on the needle.  The second time I flew it a bit richer.  I did horizontal eights as well and flew inverted with the richer needle. It had a decent break. The third flight was the same except that half the weight dropped off before the third flight as it was only wired on.  I haven't tried vertical eights yet which is the high point of my accomplishments.  I am a bit afraid of the Fox burp. It started to run strange near the end of third flight. I suspect a loose engine, tank or fuel in the dirt line - (dirt in the fuel filter).    I will hopefully be able to fly some more soon.  This Magician is fun.  As it was before it was uncontrollable.  It's a new Magician.

Thanks for all the advice.


 

[Steve Helmick]

There are, of course, various "spinner weights" and brass spinner nuts that will quickly and easily adjust the CG. Since you have a profile, you can use extra-long bolts on the lower engine mounting bolts and add a few of the 1/2 oz SIG/Brodak lead weights to those. Use the existing center hole and add a second hole, so as to pickup both bolts. I did this with elastic lock nuts on flatwashers against the engine lug, then a flatwasher, the lead weight, another washer and another lock nut, & worked well. I haven't noticed any evil tendencies from a spinner weight, however. Adding a heavier and more effective muffler is my first choice, however.  Steve

[Allen Eshleman]

I found out that the change in the engine sound was indeed loose engine bolts.  Now - to find the loctite.

I haven't   secured the weights yet.  It already has a weighted spinner.  It actually doesn't have a muffler.  That's a great idea.   I may investigate that.  I was flying at a camp ground and woke up my nephews one year old at 7:45 in the evening.  They told me it sounded like a chain saw.

[Allen Eshleman]

I epoxied 1 1/4 oz of weight on the lower lip of the engine opening at the very front and secured the engine with an extra set of bolts washers and lock washers.   On the three flights mentioned above I had the weights wired on to test out that option.  I had an ounce plus a fishing sinker.  After the fishing sinker came off, it still flew well so I settled on 1 1/4 oz.

[Jim Kraft]

On profiles I many times use bolts long enough to put nylon locking nuts on the end up against the blind nuts. You will never have loose engine bolts again. Magicians are cool planes.

[RknRusty]

On profiles I many times use bolts long enough to put nylon locking nuts on the end up against the blind nuts. You will never have loose engine bolts again...

And unlike JB Weld, the nylon lock nuts allow you to loosen the bolts when the plane is in the hangar. I like to do that to keep from compressing the beam wood. I hang a red tag on a string from a nut as a reminder to tighten before use.

[Douglas Ames]

I,ve never understood why so many people want to address problems with band-aids instead of fixing the problem!

Put the CG where it belongs...

Randy Cuberly

... Or extend the nose during the build if using a light engine (Fox .35).
I like the idea of weight in the backplate, but only on a "built" model.
P.P.P.P.P.P. = Proper Planning Prevents Pi## Poor Performance.

[Allen Eshleman]

I like the idea of extending the nose.  Actually,  this is a hand-me-down with a hand-me-down engine.  I am grateful for the gift.

[Dan Berry]

Midasize it.
Not having a muffler and needing noseweight would seem to be an easy equation.

[Jim Kraft]

I had one Magician with a Fox 35 and before adding a muffer I made a piece of steel 1/8" thick with holes to match the engine mounting bolts. I then used long bolts to mount the engine and put the steel on the left side of the fuselage for added nose weight. It worked well. I later put on a stock Fox 35 muffler and took off the weight.

[Peter Grabenstein]

One way to do it is to use a heavier muffler on the engine. If you are using a tongue muffler, switch to to regular Fox 35 muffler.

You can use stick-on weights from Brodak. They might come off after a while, so keep an eye on them. You can glue or bolt them on.

http://brodak.com/stick-on-weights.html

Other options include a Brass spinner nut (Harry Higley Heavy Hub) or a weighted washer. I forget who makes the washers.

-Chris

ps. I stick them (stick on weights) on the nose opposite of the fuel tank.

sure off topic
I get my stick-on weights for a can of beer or two
from the "Tires and Rims" dealer next corner.
They use them to balance wheels, aluminum rims with tires.
Saves me bucks for shipping.

Peter

[Allen Eshleman]

Actually, the weights I glued on were stick on weights from some place.  I pulled them off of a plane that ended it's earthly sojourn. 

[Steve Helmick]

I've seen many planes with stick-on weights, but they weren't stuck-on for very long...if you catch my drift.  Steve