IMAC Delro 2.5M Raven Build
- Thread starter Wacobipe
- Start date
Wacobipe
100cc
@sleepyc ...your in the wrong forum section...this is IMAC Builds...not 3D builds! This plane is gonna have 15-20 degrees of surface deflection...not 45-50!
I actually am thinking of re-engineering the hinge lines so that they rotate around a single hinge pin , control surfaces will have round leading edges, and will insert into a concave flying surface trailing edge. I never met a build project I couldn't make harder than it needs to be!
I've seen this idea on a CARF...I'll find photos and post them here as I do want some feedback from others.
Wacobipe
100cc
So here are 2 alternatives I am considering for hinging my control surfaces:
1) The simple, intelligent approach is to build up the LE of the control surface so I can make them rounded instead of V-shaped ( this will be done in order to smooth the airflow over the surface providing more precise control). The TE of the wing/stab would be left squared off as designed and I would use Robart Hinge Pins to hinge. This would be the easy approach, present no challenge to my skills
, and would still require the hinge gaps to be sealed.
2) Alternatively, I saw an intriguing approach some months back over on "The Site That Shall Not Be Named"... Posted by Dean Bird on his CARF Extra 330SC build. He used a single carbon rod slid through vertical plates with a nylon bearing in each. Pictured below. This approach will require a lot of redesign and I'll have to build and secure those vertical plates in my foam/sheeted wing...but if I pull it off it would be awesome! I would also build small surface extensions off the TE of the wing/stab covering the hinge gap and eliminate the need for gap sealing!
what are the thoughts from the expert builders who are watching this thread... You know who you are!
1) The simple, intelligent approach is to build up the LE of the control surface so I can make them rounded instead of V-shaped ( this will be done in order to smooth the airflow over the surface providing more precise control). The TE of the wing/stab would be left squared off as designed and I would use Robart Hinge Pins to hinge. This would be the easy approach, present no challenge to my skills
2) Alternatively, I saw an intriguing approach some months back over on "The Site That Shall Not Be Named"... Posted by Dean Bird on his CARF Extra 330SC build. He used a single carbon rod slid through vertical plates with a nylon bearing in each. Pictured below. This approach will require a lot of redesign and I'll have to build and secure those vertical plates in my foam/sheeted wing...but if I pull it off it would be awesome! I would also build small surface extensions off the TE of the wing/stab covering the hinge gap and eliminate the need for gap sealing!
what are the thoughts from the expert builders who are watching this thread... You know who you are!
Last edited:
Wacobipe
100cc
Here's a bit more info from that Extra 330 SC build on the hinges:
He used Nylon snap-in bearings from McMaster Carr (7817K53)...these snap into those vertical hinge points...in the CARF they are molded into the plane...in mine they will need to be made, slots cut, and then glued in in some rigid fashion. Then I'll need to find a really long drill bit to drill them all in-line so the hinges work properly (or drill them, and slide the rod through when gluing them in place to hold them in alignment). Through these he slides a 4mm Dia. carbon tube...cut 1/8" short of full length at both ends...this shortness gives a recess to place a dab of epoxy, holding the rod in permanently but also making it easy to cut that dab of epoxy out of the end and pull the rod out if you ever needed to for repairs...pretty slick idea!
He used Nylon snap-in bearings from McMaster Carr (7817K53)...these snap into those vertical hinge points...in the CARF they are molded into the plane...in mine they will need to be made, slots cut, and then glued in in some rigid fashion. Then I'll need to find a really long drill bit to drill them all in-line so the hinges work properly (or drill them, and slide the rod through when gluing them in place to hold them in alignment). Through these he slides a 4mm Dia. carbon tube...cut 1/8" short of full length at both ends...this shortness gives a recess to place a dab of epoxy, holding the rod in permanently but also making it easy to cut that dab of epoxy out of the end and pull the rod out if you ever needed to for repairs...pretty slick idea!
Jetpainter
640cc Uber Pimp
I did a pocket hinge many years ago on a Byron Corsair. It used Robart hinge points. The control surfaces were round on the front and the hinge was buried to where the knuckle was at the radius point of the circle. The front of the hinge had a brass tube extension that was JB welded on. The stabs and wings had thin plywood strips mounted flush into the wing sheeting to cover the gap then glassed over so it all looked like one piece. It looked really good and worked great. The drawback is if you ever needed to service them you were screwed. I guess you could use one single wire/pin going through all the hinge points. Seems to me I read somewhere that someone did the single wire in Robarts on one of the forums.
I don't have any good pictures of the hinges on the Corsair, but I may have the drawings around here somewhere.
I don't have any good pictures of the hinges on the Corsair, but I may have the drawings around here somewhere.
Jetpainter
640cc Uber Pimp
Thanks!
Unfortunately I didn't get to fly it. Shortly after those pics were taken it went into a crate, and went south of the border to the guy I built it for.
Unfortunately I didn't get to fly it. Shortly after those pics were taken it went into a crate, and went south of the border to the guy I built it for.
