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Author Topic: Modified twister  (Read 2472 times)

Offline John Rakes

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Modified twister
« on: August 04, 2008, 05:50:58 AM »
Although I like the Arf/Arc line of planes today from Brodak. I am beginning to build my own, and now about 1/2 through a twister. I have lengthened the fuse by 2 3/4 inches and added built up wing tips to a span of 52 from stock 48 inches. Painted the fuse with Duplicolor and plan to cover wings and tail feathers with UltraCoat. Question is should a larger elevator and stab be made to compensate the longer moment between the flap and elevator? I have heard you should and other say there is no difference. I have a P40 stab/elev. I have cut off the last bay shortening the span by about 3 inches. Does this sound like a good thing? If not how much should I add to the stab/elev? Thanks John Rakes
I no longer have software to add pics.
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Offline Mark Scarborough

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Re: Modified twister
« Reply #1 on: August 04, 2008, 07:28:41 AM »
John,
I cant remember exactly but it seems the Fancherized twister added an inch to each stab tip, so increasing the span by 2 inchs overall. Adding stab area IMHO is not a bad thing. Mine was done this way and flew  pretty darn good. I also added half ribs in the wing, so thats another thing to consider.
For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137

Alan Hahn

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Re: Modified twister
« Reply #2 on: August 04, 2008, 08:00:07 AM »
In the original set of articles by Ted Fancher, the "only" aerodynamic modification was the lengthening of the fuse. The wing and stab/elevator stayed the same.

Of course there were some other changes (fuse tripler, adjustable leadouts), but the plane was basically just a stretched Twister.

This is not to say that all of the other mods aren't good but they were later additions to the "Classic"   LL~  Fancherized Twister!

Offline Balsa Butcher

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Re: Modified twister
« Reply #3 on: August 04, 2008, 10:33:37 AM »
Wingtip extensions were not part of the originally published Fancherized Twister package - but they couldn't hurt.  Although not mentioned in the article the larger stab / elevator is a good idea - per Ted verbally when he was checking mine out many years ago.   If not covered yet, go with the half ribs between the main ribs per Mark's suggestion.  The will result in a more efficient / stronger wing at with negligible weight gain.  The entire Fancher-ized Twister series of articles can be accessed through Heeman Lee's "Aeromaniacs" web page.  Good choice for a plane - it got me into "Advanced" where I have remained for the past 18 years - might be time to build another Twister!   ;)
« Last Edit: August 04, 2008, 11:05:46 AM by Pete Cunha »
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Offline FLOYD CARTER

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Re: Modified twister
« Reply #4 on: August 04, 2008, 11:03:40 AM »
This is what a "full house" Fancherized Twister looks like  All the bells and whistles:

Fuselage side area increased aft of wing.

Wing tips  - adds 2" each side.

Elev/stab increase.  2" added in span, 1/4" added in chord to stab (spruce strip at hinge line)

Flap chord increased with 3/8" hard balsa strip at hinge line (also stiffens flaps)

Half-ribs

Fuse length extended per Fancher

Carbon tube pushrod

O.S.35 FP.  All up weight 40 oz

Covered in silkspan with red dye added to clear dope.

Only 2 flights so far, but it shows great promise.

Floyd in OR
« Last Edit: August 04, 2008, 11:38:40 AM by FLOYD CARTER »
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Offline John Rakes

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Re: Modified twister
« Reply #5 on: August 04, 2008, 11:43:16 AM »
I am gonna go with new stab/elev made out of 1/4 balsa and taper the elevator. Thanks for the dimensions. This thing will be ready in no time. Thanks John Rakes
John Rakes

Offline Mark Scarborough

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Re: Modified twister
« Reply #6 on: August 04, 2008, 11:54:23 AM »
I beleive one other thing that Ted mentioned in the articles I read was to shorten the vertical stab . This wasnt so much an aero change but more an "oh crap" change in that if you tipped it over on landing the vertical would be much less succeptable to getting damaged or broken off when it flipped.
For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
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Offline Andrew Hathaway

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Re: Modified twister
« Reply #7 on: August 04, 2008, 11:55:06 AM »
Just recently I finished two modified Twisters with the longer fuselage.  One was finished with the stock kit dimension tale, the other had more tail area.  After flying both, it's my opinion that the larger stab/elev does little or nothing for the plane, or at least the plane with the stock stab/elev flies better.  It also happens that the stock tailed plane has less power, and weighs less.  

On my Twister I chose to save weight, complexity, and materials by not installing half ribs, or the fuselage tripler.  It went together very quickly, turned out very light, and flies great with a 20fp.

Edit:  The entire series of Fancher articles on the Twister can be viewed by any AMA member at www.modelaircraft.org in the online Model Aviation archives, in addition to other sources.

Offline roscoe

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Re: Modified twister
« Reply #8 on: August 05, 2008, 01:13:19 AM »
Hello, Here are the elev./stab dimensions on my F-twister. Stab; span=18 1/2", mid chord=3", tip chord=2". Elevators; span= 9 1/4'' inboard chord= 2 1/4", tip chord= 1 7/8". I like to use 3/8 balsa for the stab, and 1/4" for the elevators. I've been flying mine for 5 years. I first powered it with a blue LA 40, then a stunt tuned FP 40. Now it's motoring round the F2B pattern to my complete satisfaction , I must add, using a new box stock  natural finish LA 40 especially in the wind. Lastly, when setting your model up ; use the Fancher forward CG (centre of gyration) position. Hope this helps. Cheers Roscoe  "Flying stunt is an exact art".

Offline Dennis Moritz

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Re: Modified twister
« Reply #9 on: August 05, 2008, 01:57:04 PM »
This Twister has half ribs, wing tips, and a stock stab mounted in the stock place. It turned out heavy, tho, with 1/8inch five ply in the nose and motor mounts extended back past the leading edge. Somewhat of a porker, it surprised me at 45 ounces. This with a stock 40fp and a tongue muffler. Next time I won't use kit wood. With the right wood, seems to me wing tips and half ribs won't add that much. Choosing the right leading edge stock might even cut an ounce or two. At Brodak I turned in a 450 plus in Intermediate Nostalgia. Not bad for me. At the moment I'm trimming it with the help of some Philly Flyers. Plane picked up something of a warp it seems from sitting out there in the hot summer sun. Also, it never was flight trimmed correctly. I saw an excellent flying Fancherized Twister at Brodak. It used a modified FP 40. Seemed to me the Fancher changes smoothed out maneuvers also gave the plane a decent corner. I could see where building the Twister as light as possible and sticking a 20 or 25 in the nose could work out well. I've had to put an ounce in the tail so far. Might need some more. Nose weight definitely slows the turn and softens the corner. I think a bigger stab allows the cg to be moved further to the rear without upsetting stability. Quickening the turn and sharpening the corner.

« Last Edit: August 05, 2008, 09:04:38 PM by Dennis Moritz »

Offline FLOYD CARTER

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Re: Modified twister
« Reply #10 on: August 06, 2008, 12:59:06 PM »
I used 1 mm birch aircraft plywood for fuselage doublers instead of the heavy stuff in the kit.  Fuselage tripler was some 3/8" sheet I had handy.  No fiberglass or anything around the front end.  The 1 mm ply provides the same stiffness without the weight.  Balanced without any added lead anywhere.

40 oz with O.S. FP-35

Floyd Carter
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Offline Phil Coopy

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Re: Modified twister
« Reply #11 on: August 06, 2008, 02:31:48 PM »
Nuther mod you can have fun with.....a Rabe rudder.

Phil

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