News:



  • March 28, 2024, 01:06:10 PM

Login with username, password and session length

Author Topic: Sheet wing stunter  (Read 3770 times)

Offline rob biddle

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 231
Sheet wing stunter
« on: November 30, 2006, 02:50:44 AM »
  Hi folks,
 I recently got a copy of a plan that I had been eyeing off for a few years.

 It's for the "Stunt- wind", a 46" span sheet wing profile model for a .19- .25 engine.
(published in AMI, 2001)

 According to the designer it can fly at around the "middle" advanced level with the right pilot and good trim. ;D

 I'm seriously thinking about "slapping" one together after I finish my RSM T-bird (in final paint stages now.)

 After having crashed my best flyer (which was just about worn out) I haven't had any serious flying for a few months and as a result have gotten fairly rusty. HB~>

 I reckon one of these things could probably be framed up in 2-3 nights with out too much trouble and with a rough and ready paint job could be ready to fly inside a week or so.

 Could be a cheap and easy way to practise some low bottoms without risking a large time or cash investment. ;D

 There was a fair bit of sheet wing stunter development out here about 15 or so years back which resulted in the "Mini Nobler" and the "Mini Bandolero". Both .15 - .21 size models. Apparently they both fly reasonably well though I haven't seen them.

 Anyway, I was wondering if anyone has any experience with a "sheet winger" and knows of any traits that I may expect or need to trim for.

 If not, then I guess that it will be a case of just "suck it and see". **)

 Could be a fun little experiment. <=
   
  Cheers, Rob.
Robert Biddle

Offline Terry Fancher

  • AMA Member
  • Trade Count: (0)
  • New Pilot
  • *
  • Posts: 15
Re: Sheet wing stunter
« Reply #1 on: November 30, 2006, 08:25:12 AM »
Rob,

A number of years ago Big Art Adamisin was invited to Oz and gave clinics and judged some.  He came home talking about someone (I forget who) was flying a sheet winged stunter and that it flew surprisingly well.  I expect it might well be the same design you're talking about.

It's no secret that a flat plate can produce lift and, if flown within its limits (keeping the angle of attack below critical), could fly recognizable maneuvers.  The tails on many an early general aviation airplane were nothing more than flat plates and did a perfectly acceptable job of pitch control. 

Just a guess, but I think that flaps would be a great asset on such a design because they would allow an increased lift coefficient without the need for high angles of the leading edge to the ambient airflow, thus delaying critical angle of attack and minimizing the tendency to stall under load.

Ted Fancher

Offline rustler

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 719
Re: Sheet wing stunter
« Reply #2 on: November 30, 2006, 01:26:31 PM »
I've seen a Stuntwind fly, and it is surprisingly good. The patterns were better than a lot you see in comps with regular models. I recall there was some corres. concerning a similar design in Oz. (I think).
Ian Russell.
[I can remember the schedule o.k., the problem is remembering what was the last manoeuvre I just flew!].

Offline rob biddle

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 231
Re: Sheet wing stunter
« Reply #3 on: November 30, 2006, 02:14:57 PM »
  Thanks Gents, a few more details in no particular order.

 I neglected to mention that the "Stuntwind" is flapped and has a reasonable moment arm length.

 The stab span is half of the wing span and I guess about 30ish % area.

 The plans recommend a 4" bellcrank with fairly long horns (for the size of the model) and a flap to elevator ratio of 1:1.

 I figured that the pointy leading edge of the flat plate would tend to make the wing stall at a fairly low angle of attack, even if built quite light. Hence the 1:1 ratio.

 Maybe the slow controls would help to open out the corner radius slightly to prevent the wing from stalling prematurely.

 The balance point shown on the plan is at about 25-26% root chord.

 I reckon that an Fp.20 would be the ideal, unfortunately I haven't got one (yet!), though the nose would have to be shortened a bit to get it to balance with the factory muffler.

 The original model used an old O.S max .20 quite successfully, so my old (pre Fp) Max .25 should do ok.

 Cheers, Rob.
Robert Biddle

Offline phil c

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2480
Re: Sheet wing stunter
« Reply #4 on: December 01, 2006, 09:23:44 AM »
the biggest "trait" of a sheet-winged plane to watch out for is that once you get the wing overloaded it takes quite a bit of opposite control or opening up the maneuver to get it flying again.  The fourth corner of a square loop or the fourth turn in the hourglass are really tough points.  Push the corner just a bit too hard and the drag goes through the roof(the plane slows a lot), lift drops way off, and the turn opens way up.  To get the wing flying again you have to usually completely neutralize the controls and let it fly straight and pick up some speed.  I don't know that the wing really stalls.  Most CL planes are so lightly loaded and overpowered it seems to be more a matter of the wing not producing lift and the plane is suddenly trying to fly on just the prop.  If you put almost any kind of airfoil on the wing these problems go away, so I'd say you would be better off with using a simple foam wing with over/under spars and a trailing edge to hang the flaps on.  Just as easy to build, tougher(sheet balsa is prone to splitting and shattering), and easier to get flying well.
phil Cartier

Offline rob biddle

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 231
Re: Sheet wing stunter
« Reply #5 on: December 01, 2006, 07:18:59 PM »
  Hi Phil, a couple of interesting points for sure.

 I overlooked the fact that if I run out of room in a corner there will be pretty much no saving of the thing! **)

 The sheet wing models may be quick to build but this will be negated if there is nothing left to repair after the inevitable crash. I expect that they will explode into a pile of splinters without to much effort.

 As I have no experience with foam wings a constant chord, built up wing would only add an extra evening or so of construction time and certainly be easier to make fly well.

 Even if it is quick to build, a sheet wing stunter is probably more of a novelty than a serious practise plane. ;D

 May try one anyway, even if it doesn't last real long it could be a laugh!

Cheers, Rob.

Robert Biddle

Offline phil c

  • 21 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2480
Re: Sheet wing stunter
« Reply #6 on: December 05, 2006, 01:49:00 PM »
Well, the RC guys have a lot of fun with their foam board flyers.  Dick Sarpolus has published a couple for CL, both glow and electric, that fly pretty well.  I got some handle time on them.  He built one using Li'l Hacker II cores and the same plane with a larger flat wing with a more powerful engine.  They both flew.  I think the LH wing version was a little easier to handle in corners, but both were had such a low wing loading that stalling/prop flying really wasn't a problem.
phil Cartier

Offline Peter Anglberger

  • Trade Count: (0)
  • New Pilot
  • *
  • Posts: 19
Re: Sheet wing stunter
« Reply #7 on: December 25, 2006, 06:30:33 PM »
I don't often post but I could not resist this one.

Sheet wing stunt models( the all sheet) Gieseke Nobler and Bandalero, were first developed by Frank Coombs in South Australia in the late 70s.

These flew very well and are an ideal model to learn and improve the pattern.
Frank subsequently developed the ideas and came up with the Yardstick
which another South Australian Leon Baird refined (and later kitted), placing
in the top 10 in the Aussie Nats which Big Art attended. (I'm not sure of the year
as I wasn't there). Leon's model still exist and flies well despite several 'write
offs' where the repair involves only epoxy and a little extra glass cloth reinforcement.

The Stunt Wind mention is basically a copy (notice I didn't say ripoff although
it wouldn't be an unfair comment). I know this as I have both plans and the Yardstick predates the Stunt Wind by 7 or eight years.

The bottom line with the sheet wing stunters is that they must be light. You must use contest grade light wood and must set up the controls as per the plan.
The Yard Stick uses a large bellcrank and 'correct' geometry long throw horns,
and a chicken hopper tank. Change any thing and you 'stuff up' the concept.

As Phil mentioned the all sheet wings are prone to stalling if the corner is banged really hard. However they do recover if you let them fly out of the mess.

As I said they need to be built as per Frank's concept other wise they become very ordinary. I designed my own without heeding Franks design principals and suffered an inferior model. I'm going to build a Yard Stick properly even though I now fly the pattern confidently if not that competently just to see what I was missing. These models are suitable for raw beginner fliers yet still competitive in most local competitions

If you want to find out more there is plenty of info at http://www.vicstunt.com/, see the 'History' section, scrolling down to "Yard Stick"

Offline ray lloyd

  • Trade Count: (0)
  • New Pilot
  • *
  • Posts: 6
Re: Sheet wing stunter
« Reply #8 on: February 03, 2007, 02:38:50 AM »
Ref the Stunt Wind, this model is a rough copy of the Classic Yard Stick, it has a side mounted motor, the Yard Stick is inverted. I have built several y/sticks and Mick Broadbent copied his S/wind design off my last one, one of the best features of the Y/Stick is the inverted motor so if you go for side mount it becomes just another profile model. my last one was powered with an MDS 25 running at full chat and this is important as the model tends to stall on corners and slow down, using a motor on full power helps to pull it through this and it becomes very easy to fly accurate, best of luck with it.
                                           
                                                             Ray

Offline Annette Elmore

  • Trade Count: (0)
  • Lieutenant
  • ***
  • Posts: 101
    • Lots of UK-related stunt stuff
Re: Sheet wing stunter
« Reply #9 on: February 22, 2007, 08:35:46 AM »
I've seen Ray fly his Stunt-wind and it does go well - the bending of the sheet wings can look a bit alarming though......

I thought that it was the Yard-stick that had a side mounted motor and the Stunt-wind had it inverted!

Tony

Offline Geoff Goodworth

  • Trade Count: (0)
  • Captain
  • *****
  • Posts: 808
Re: Sheet wing stunter
« Reply #10 on: February 23, 2007, 05:08:52 PM »
Tony, I think you are correct.

Cheers, Geoff

Offline Air Ministry .

  • Trade Count: (0)
  • Admiral
  • ******
  • Posts: 4978
Re: Sheet wing stunter
« Reply #11 on: March 30, 2007, 07:39:46 PM »
  Hi Phil, a couple of interesting points for sure.

 I overlooked the fact that if I run out of room in a corner there will be pretty much no saving of the thing! **)

 The sheet wing models may be quick to build but this will be negated if there is nothing left to repair after the inevitable crash. I expect that they will explode into a pile of splinters without to much effort.

 Try flying it in a paddock,when its not sunbaked.

 they tend to go in like a javlin.You then pull it out,hose out the engine , and your away again.
They used to boil the nylon props so they wouldnt break.

Similar principal to 'Olde english combat ' ?

Most fields in N.Z. that arnt well drained ,in winter,offer survivable rates of decelleration for 'vertical landings' !

                                                                                                                                                           M.S.

P.S. look at the original; "mini Nobler , Genisis and Olimpic "  artical in Airbourne .

Inverted Engine, Chicken hopper tank, Sht . wing  (3/16" ! ) Y - bellcrank.

Its the 'fly it in a week',if youve got all the bits plane.
Probly good for fitting 1/3 or 1/2 doz. .049s on the wing,to see what happens ? ?




Advertise Here
Tags:
 


Advertise Here