Design > Stunt design

Huge flaps?

(1/1)

Matt Brown:
I’ve been thinking of this for a while and buddy Bill Durr picked up a nib RC 3D profile ARF at a swap meet Saturday. We are planning to convert these to CL stunters for profile contest duty. The flaps/ailerons on these are huge compared to common CL stunters. What are your thoughts cutting them down to more conventional sizes or use them full size but rig for lower flap to elevator ratio or stay 1:1?
I have a design that I’ve flown 3D with for many years and have considered doing this as well. One of the issues is the TE has a good bit of sweep so I’m not sure how best to link up the flaps. 

Ideas, thoughts on these situations???

Thanks, Matt

Dan McEntee:
  Well, right off the top of my head, do a search on the forum here for "Lucky Boxes" with are some hard wood inserts that are built into the flaps so that you can use a common horn assembly. The inserts are wide and are slotted horizontally so that as the flaps actuate the arms of the joiner don't bind andthey will move freely. They are called Lucky Boxes because they were conceived by a gentleman named Lucky Pyatt who was a noted southern California stunt flyer.

  Making the flaps more barrow would be in order but mare make the wings look funny?  An option would be to build out the trailing edge, even if it's kept flat. Limiting the throw would help some also. The SIG Fazer was flown quite a bit as a C/L stunt model and I think Mike Pratt designed it as such and the instruction and plans that came with the kit showed how to convert to C/L. The airplane may fly OK but depending on airfoil and such, I would not expect too much out of it.
  Type at you later,
    Dan McEntee

Brett Buck:

--- Quote from: Matt Brown on December 18, 2024, 04:53:36 AM ---I’ve been thinking of this for a while and buddy Bill Durr picked up a nib RC 3D profile ARF at a swap meet Saturday. We are planning to convert these to CL stunters for profile contest duty. The flaps/ailerons on these are huge compared to common CL stunters. What are your thoughts cutting them down to more conventional sizes or use them full size but rig for lower flap to elevator ratio or stay 1:1?

--- End quote ---

     I have always had better luck with smaller flaps and around 1:1. 1:1 and giant flaps is not really a reasonable possibility, large chord flaps have disproportionate huge hinge moment and you will not be able to deflect them very far with the line tension available. If you can't deflect the flaps very far, you also cannot deflect the elevator very far.

  Naturally, if you are cutting the flaps down, reduce the chord and leave the span.

       Brett

Navigation

[0] Message Index