How Many Hinges To Use

[Brian Thwaites]

Ok guys how many hinges would you use on a 25.75" long flap, ie: on a Magnum it shows five on each which to me seems over the top. I was thinking three maybe four.

[Bob Reeves]

Ever seen a stunt ship with the outboard flap hinge broken.. I've seen a couple.. Use all 5..

[Wynn Robins]

use all 5 - put two relatively close together at the root by the control horn - just to give some added strenght against the force of the bellcrank/push rod.

one thing I have learnt along the way - the plans are usually drawn by people that know what they are doing - and do things for a good reason......

[Clint Ormosen]

I'm with Bob. Use 5 of them. Any less for that amount of span and the flap will start to bow between each hinge while under a load. Not good.

[wmiii]

I would use at least 5, on mine I've used 6, with 2 close together at the tip of the flap.

 Walter

[Jim Pollock]

 I agree with all that has been said.  Aerodynamic forces acting on a Stunt Ship going 50-60 is more than you think.  I once snapped a spar in an Ares doing plain old inside loops!

Jim Pollock   

[Bill Little]

use all 5 - put two relatively close together at the root by the control horn - just to give some added strenght against the force of the bellcrank/push rod.

one thing I have learnt along the way - the plans are usually drawn by people that know what they are doing - and do things for a good reason......

HI Wynn,

Since I epoxy the horn to the trailing edge (with brass clips) and add CF tow over the clips, I have not had a problem near the fuselage.  BUT, I HAVE seen problems on larger planes at the distal end of the flap.......

[linheart smith]

Like they said. No cheating . No short cuts on controls.

Six each side. If you don't have one, buy a slot Cutter.

Check for alignment. Up/Down. Right/Left. Back/Front  Plus. Tie the control horn to the trailing edge with wire and epoxy over copper tube bearings.

Linheart

[Shultzie]

It would seem that the more this post continues "how many hinges thang"  4 -5 -6 etc...AH

Neva nuff hinges...huh? NOT NECESSARLY SOOOO, SAYS THE STUNT BIBLE!
Although hinge failure happens...but usually with our stunt machines....it is not the hinges themselves. The majority of flap elevator hinge failures on our stunt models boils down to just one often  consistant over-looked item.
FUEL RESIDUE-MOISTURE RESIDUE finding its way to the bare-boned naked balsa (or wood) joints which then swells and breaks down the balsa around the glue joints---then throw in the constant wing-flap hinge loads...etc.
SEAL THOSE HINGE LINES!!
 Usually it isn't a matter of "HOW MANY HINGES!" EVEN A FULL LENGTH PIANO TYPE HINGE would also fail....if those parts are not protected from all outside foreign moisture,and exhaust etc. Amazing how much crappola' thrown up by that whirling prop can find its way into the hinge lines.
BOTTOM LINE!!!
TAKE AS MUCH CARE IN SEALING THOSE HINGE JOINTS AS POSSIBLE!

From my experience from my daze watching old flutter model movies, it never ceased to amaze me just how many forces work on a wing hinge fittings.....usually boiling down to one simple thing thang....actually quite rare indeed...was the fatigue of the hinge part "usually metal fatigue of the pin itself"
Lets just keep in mind on most stunt models it is that ol' fuel residue, cleaners...moisture...etc that finds it way into the smallest unprotected bare wood parts...AND NOT FATIGUE OF THE HINGE
Then again...my old trumpet playin friend...Ray Klein, Boeing's noted principle acoustical engineer also suggested how sound or harmonics...could also play a part in inducing flutter into a flap or elevator on our stunt models (after seeing one of Joe Dill's flaps start fluttering and explode into many little pieces after one tip of his cut down 13.6 prop parted off the front of his model from that unbalanced prop.)
Ray laughed...and replied "DUMB QUESTION SHULTZIE...VIBRATION CAN START ANY STRUTURE PART TO SET UP HARMONICS, RESULTANT OVER TONES..ETC...THAT CAN INDUCE FAILURE...OR EVEN  INDUCE VIBRATION.....and as far as that balsa flap exploding into pieces... BOTTOME LINE:pure and simple was the force induced by the UNBALANCE PROP ITSELF!

Gads...forgive the rant..n' drivel!  JUST SEAL THOSE HINGE POINTS.
 

[Bill Little]

Actually, Brother Donaldo Shultzie, you can go through life like me........ the *blind hog*..............       

[Will Davis]

Brian,
      As Bill and others replied to your question , the number of hinges and the location is important. I have used some of the quarter scale Dubro Hinges for years, A minimum of four for each flap( 8 total)  and two for  each elevator( 4 total)  .You will need to use more hinges if you use the standard size hinges . They will have smaller bearing surface and less contact area for the adhesive to hold  them to the surface .
      Take a good look at the plans as the designer usually shows the number and location of hinges


Will

[john e. holliday]

No matter the number of hinges, I never rely on the glue to hold except for silicone glued hinges.   I put at least one tooth pick thru each tab.   

[Dean Pappas]

Hio Brian,
You will never see a Stunter die because it had too many hinges.
I have lost an airplane for having too few, and the problem always seems to start at the tips.

best of luck,
Dean Pappas

[RandySmith]

I would use at least 5, on mine I've used 6, with 2 close together at the tip of the flap.

 Walter

HI Brian

I will echo  what Walt  said, ALL of my 50 to 65 size ships use 6 hinges  2 at the tips  and the other 4 spaced evenly to the root.  It is the tips that take a beating and also have a lot of vibration transmitted to them.  many years ago I had a problem with the tip hinge breaking, after I went to 6 ,  with 2 near the tip I have had zero  problems with hinges.

Regards
Randy