Edge 540 27.4% Build
#353
Vince I know you are good and the profile will be as good as the rest of it but I'm curious why you wouldn't just make quater ribs for both sides and cover with 1/16" balsa skins like the wings. Just picking your brain which is full of good ideas and you picked the hard way.
Love watching you work.
Leroy
Love watching you work.
Leroy
#354
I have to add something, I have done what you are doing and while you may know how to go about it I'm going to add this anyway. With a root and tip profile pattern your good to go but a flat bar only sands flat spots and are only good to rough in the shape, Then I use a shorter bar (6") and mark radial lines 3 different places and sand the rest radially gradually moving down the foil. you will see the lines start to go away and when they are all gone you are nearly done. You can find the high spots with a straight edge mark them and finish it up with 220 grit on the long bar sanding in the same manner. Heck you probably got it done by now, maybe someone will get something from this.
Leroy
Leroy
#355
Thread Starter
Jim, the roll of sandpaper that you can see in the photos comes in 3 different grits (80, 150, 220), and they all have the adhesive already applied to them. You simply unroll to the length needed and stick right on your sanding bar. The width of each roll is slighly wider than the bar and will need to be trimmed to fit. Very convienient and quick...
Anthony, one of these planes I will try it, but not on this one as I am trying to keep the weight down to a minimum. UltraCote (gasp) will be used on the wings and all control surfaces. The fuse, tail fin and flat stabilizer will get glassed and painted.
As far as the profile on the flat stabilizer goes, I am not using any type of template, I am doing it by eye and am trying to follow the profile as indicated in the plans. Because of the way this is constructed I could make a tip template but not one for the root. Leroy, I had considered doing what you had suggested, but that would have required me to re-size the wood used to make this stabilizer. I can't say that I have ever done it this way before, and that exactly the reason that I decided I would go ahead and pull the trigger and do it this way. It is a lot of work, but I have the leading edges up to the chord completed and I am happy with how it came out.
Anthony, one of these planes I will try it, but not on this one as I am trying to keep the weight down to a minimum. UltraCote (gasp) will be used on the wings and all control surfaces. The fuse, tail fin and flat stabilizer will get glassed and painted.
As far as the profile on the flat stabilizer goes, I am not using any type of template, I am doing it by eye and am trying to follow the profile as indicated in the plans. Because of the way this is constructed I could make a tip template but not one for the root. Leroy, I had considered doing what you had suggested, but that would have required me to re-size the wood used to make this stabilizer. I can't say that I have ever done it this way before, and that exactly the reason that I decided I would go ahead and pull the trigger and do it this way. It is a lot of work, but I have the leading edges up to the chord completed and I am happy with how it came out.
Last edited by VincentJ; 12-10-2013 at 05:58 AM.
#357
Thread Starter
Well my plans were to spend the entire day in the workshop, but mother nature had different plans for me. Spent half of the day either on one end of a snow shovel or snow blower...
I did manage to build the two elevator halves as you can see. I decided to skin them with 1/16" balsa for added strength. 1/2 oz. lead weight was epoxied in each counterbalance tip. As soon as the epoxy sets I will be able to skin the opposite side of the elevator. Once that is completed I can continue the sanding of the airfoil on the trailing edge of the stabilizer...
I did manage to build the two elevator halves as you can see. I decided to skin them with 1/16" balsa for added strength. 1/2 oz. lead weight was epoxied in each counterbalance tip. As soon as the epoxy sets I will be able to skin the opposite side of the elevator. Once that is completed I can continue the sanding of the airfoil on the trailing edge of the stabilizer...
#360
Thread Starter
Not stupid Robert. Theoretically, you are correct. The amount of weight that you add should bring the control surface to the neutral position when hinged, however the weight that I have added is per the spec on the plans. These don't however get the elevators neutral, more weight is needed which I am not adding...
You're an evil man there David!
You're an evil man there David!
#365
My Feedback: (3)
Not stupid Robert. Theoretically, you are correct. The amount of weight that you add should bring the control surface to the neutral position when hinged, however the weight that I have added is per the spec on the plans. These don't however get the elevators neutral, more weight is needed which I am not adding...
You're an evil man there David!
You're an evil man there David!
I bought 1/2 pound of #7 lead shot several years ago to solve problems like I see others having balancing control surfaces and to stop eating planes to flutter.
What I would do, since we already know the surface is 'tail heavy' is leave a 1/8" slot open on the counterbalance beam to be filled in after the rest of the sheeting and sanding is done. Then put the hinges in temporarily and fix the hole with more weight and seal it. To do that, mix up some epoxy and dribble it in and then put shoot into the slot until the surface was level. Oh, another 'trick' is to estimate the needed weight before you start by testing.
The issue here is that the lower the 'out of balance' the less the chance for servo destroying flutter to set in. I really really hate it when flutter eats something I have spent hours building, and it HAS happened! For some nasty reason it always seems to bite me on the elevator circuit. One lasted a couple of months and another really good scale job went in on the maiden for flutter...everyone there heard it.
#366
Thread Starter
Jim, nice tip on your method of controlling flutter. I like the idea of leaving a slot open!
#368
Thread Starter
Awful quiet here, you guys still with me?
Much work has been done to the horizontal stabilizer, specifically the airfoil shaping of it. I pretty much have it where I want it give or take 1/32". The elevator halves have been sheeted and are awaiting sanding ,hinging and for the 45 degree angle to be shaped into the leading edges.
Here's what it looks like, I tried to take different views so you could better see the airfoil shape.
Much work has been done to the horizontal stabilizer, specifically the airfoil shaping of it. I pretty much have it where I want it give or take 1/32". The elevator halves have been sheeted and are awaiting sanding ,hinging and for the 45 degree angle to be shaped into the leading edges.
Here's what it looks like, I tried to take different views so you could better see the airfoil shape.
#375
but it's so cool. Oh well you can always add it later. Your project is looking good, I have been in a bit of a slump with my stuff right now, I hope to get back it and finish it after all the Christmas rush is over. All this early cold weather and snow has my heating bill going into overdrive