iron eagel

Thanks Smokn!

I knew it was going to be tight for the servos either way but these 100 oz ones are a lot larger than the ones I had planed on using.
It was so tight that it was within an eight of an inch of being too tight, it was a real relief to see that they do fit.

combatpigg

My Feedback: (3)

Lookin' good! Nice job on those servos.

I think you want the built up fin's leading and trailing edges to extend all the way to the extreme bottom.

iron eagel

Cp your right about the fin thanks for catching that! I have no idea of what I was thinking of when I drew that up. Obviously not keeping the fin vertical and in one piece.
Burying the servos in the wings was the only way to get them to fit...
Another design error on my part, I should have thought through the entire control linkage thing sooner than when I did.
Parts of this thing are being drawn on the plane as I am building it.

iron eagel

Well got the elevons made up I just need to cut the reliefs in them for the torque rods, I also managed to sketch out the cooling exit a bit better.

smoknrv4

My Feedback: (11)

Oh yeah!
Lookin good!

N1EDM

My Feedback: (2)

Nice Build, Paul. I didn't know about this... Thanks for giving me the link... FYI, my Delta Vortex weighs about 2#10oz in the bones. I don't have an all-up weight yet. What is yours projected to be, and I'll have to re-read the thread to find out what you're going to use for propulsion.

Bob

iron eagel

Thanks Smokn, Bob !
Working on mounting the torque rods...

iron eagel

A bit of progress...
I finished up the trailing edge of the wing fitting the tri-stock to it as in the original design (hinges will be used on that portion), and then made up the mounting and housing portion of the trailing edge where the torque rods are going. I then fitted the left elevon and fitted it to the torque rod. Here is a couple of photos to show what little progress I have made. The first shot shows the torque rod and brass bushings for them, The second photo shows the left elevon fitted and in place.
Now on to fitting the right elevon and making the last major structural modification before installing the torque rods permanently into the airframe. The torque rods and linkages need to be finished before I add the last of the tail structure that makes up the cooling duct, cooling exit and blending of the evelon root into it.

combatpigg

My Feedback: (3)

The reason why "Mr Torque Tube Expert" over in the aerodynamics forum had trouble with his 4-40 hardware snapping was that he was relying on the threaded portion of the bolts to carry the load.
This is why I allow the unthreaded shoulder of the bolts to pass through the tube and I secure the bolts with cone shaped [and counterbored to clear the unthreaded bolt's shoulder] aluminum nuts that I make myself.
This set up is undeniably trickier with way more potential failure points than just using bent music wire...but who cares..........[8D]?
It does a better job of deploying full span elevons.

iron eagel

I plan on doing it pretty much the way you have detailed, and even going a bit further by using two push rods instead of one so that the force is applied to both sides of the torque rod, using a pull/pull configuration as a push pull actuator. I'm pretty sure that the 4-40 hardware should be able to withstand the worst case scenario of the approximately 5 pounds of force that it will have to endure, if the this plane even gets close to speed that yours did. I am using 6061-T6 3/16" torque rods with the 4-40 hardware my major concern was, twisting the 4-40 hardware out of the 3/16" torque rods, not the 4/40 hardware failing because of how I am using it. Your right this is a lot more work, and potential failure points then bent music wire, but I am fairly confident it should work for this application. I am doing this so I can keep all of the control linkage internal I feel that this setup should be better than soldering brass to music wire and make the entire control surface system a lot less elastic.

combatpigg

My Feedback: (3)

I used two "fangs" in my set up [per each elevon] and the outer fang engages the elevon at about 1/3 span.
The hardest part about this set up is to figure out how to cover it with iron on film.

iron eagel

I am relieved to hear that is how you did it, that's what it looked like from you photos! I did the pretty much the same thing with two per elevon with the outboard one being at about 1/3 the span. This seems like a much better method than having the horn on the end of the control surface. I assume you did it that way to reduce the chance of flutter (at least that is how I am looking at it). To add just a bit more stiffness to the elevons I also plan to embed .015 inch carbon fiber rod diagonally across the span like I did on the Stingray (no I am not bothering to do built up elevons this time).
A question... When you mounted your bushings for the torque rods did you secure or wrap them back onto the wing or just epoxy them in place? I was thinking a bit of glass or carbon fiber tow might be a consideration to make sure they stay with the plane, or is that overkill?
As far as covering I am doing a composite skin, and will be painting this one.
I can see where doing iron on covering with this type of arrangement would demand that you would have to get pretty creative.
I never done a film finish that I have ever been happy with how it came out, I know I can do a painted finish that's pretty lightweight ( downside is it a bit more time consuming and more work).

combatpigg

My Feedback: (3)

I epoxied the bushings to the trailing edge, but also sewed them. The trailing edge of the wing was under cut slightly before sewing, so the thread didn't stand proud of the finished surface.
A swipe of Bondo was used to hide the sewing and to bring that area flush with the surrounding surface.

iron eagel

Thanks CP,
When you say sewn do you mean with a needle and thread literally?

combatpigg

My Feedback: (3)

You can drill tiny holes and pass heavy thread [soaked with thin CA] through the holes, or you can use a heavy needle to do it through medium hard balsa. Don't bother tying off the thread, just CA it once you get a few wraps sewn.

iron eagel

Thanks!

Goinstraightup

My Feedback: (26)

Very nice project. Subscribed.

iron eagel

Thanks GSU!
I have started on the blending of the root of the elevons into the main fuselage. While it all need quite a bit more sanding and fitting before the root blends are completely done, I need to get these parts ready as they are also used to enclose the torque rods bushings and will go on when I install the torque rods. I have also started fitting the cooling duct (just sitting between the root blends to give you an idea of how it going to look) and exit nozzle, making up the nozzle is going to be a bit tricky. I am also working on the last of the fitting needed for the control linkage (thanks for the advice CP!).
So what do you guys thing of the elevon mods?

iron eagel

I finally got the elevon torque rod bushings and rods themselves installed. After a bit of fiddling around with the fitting and using a laser to line up everything the elevon root blending is now part of the airframe. The inner bushings are enclosed within the elevon root blends and when the cooling duct and body blending are finished I have no fear of them departing the airframe. The outer torque rod bushing still need to be bound more permanently to the airframe but for now they have epoxy holding them in place end I deal with them later. Everything looks like it came out pretty straight and true, and it nice to see how it looks without all the tape holding everything together!
Next up is to finish fabricating the control linkage and hooking everything up to the servos. After I get that done I can finish up the cooling duct and finish blending the body to the wing.
A couple of pictures to show the root blends with the elevons taped in place.

iron eagel

Finally got back to do enough work on this to bother posting an update.

I had to dump the original design for the torque rod horns I just don;t have the machining expertise to do something that was this small with the degree of precision needed to prevent Ackerman. The proposed horns would have looked like the example in the first photo. Oh well.

So I decided to go with a pull pull type of setup that the pieces I needed to fabricate I could actually make. It would have been nice to do a full blown push pull setup using CF push-rods but what I used instead is Sullivan gold cable in a pull pull configuration with brass horns solder to tubes the mounted to the torque rods. The second photo shows the torque rod control horns. Now for the first time in ages I could actually proceed with the build now that the elevon linkage is setup.
The next photo shows the bottom side of the duct planked and the rear of the cooling duct. It also shows the cooling duct support for the exit nozzle as well as functioning as a former to tie the trailing edge back together. The last photo shows the cooling duct fully enclosed now on to the nozzle and the last part of the blending of the rear of the fuselage into the wing itself.

iron eagel

Even just having starting blending in the cooling duct, that "hunk of lumber" hanging off the back of the airframe is starting to fade away.

combatpigg

My Feedback: (3)

That's really some nice carpentry. Excellent "spatial conceptualisation" and execution....[8D]

iron eagel

Thanks,
Right now it weighs in at 1 lb 2 oz with the elevons on all of the linkages and servos. I put all of the components in it for a weight check and I am projecting a RTF weight of about 3 lbs ( I hope), 1 lb of that is the battery alone...
Now as far as execution...
Right now I have to figure out how to modify it a bit to actually allow me the room to shift the battery back a bit if need be. It seems that the battery isn't exactly the size it was supposed to be and I have to be sure to get air all around it. I forgot about giving myself a bit of extra space if the battery size wasn't quite right I had bought a 4500 mah battery instead of the 4000 mah one I was going to use thinking close enough (oops).
I have an idea I am working on that may resolve the issues I have with the blending of the hatch are and belly, as far as flat spot it is giving me.

evan-RCU

Finally getting aromd to doing more on my build...

iron eagel

Very nice are you going with fins or wingletts?