RE: Eindecker EIII
 

HPA, I see now that you have support cables (with turnbuckles) on the rear side of the A-pylon as well. I hadn't noticed them before and was afraid that the pylon might simply be broken off on a rough landing. Still, I think if I were going to build one, I'd replace the wooden pylon with something like streamlined aluminum.

Anyway, it really does look great and I look forward to hearing about how it flies this time around.

RE: Eindecker EIII
 

Turtle Report

Aileron servos can now be mounted.......

RE: Eindecker EIII
 

Hey Art .....
Do you shim your servo off the plywood so it get the full shock absorbing function of the rubber isolators?
And will you pin your mount blocks or just trust the glue ?
And do you think Greg will wear his turtle pj's at "Wings for Kids" this June?


Cheers,
HPA

RE: Eindecker EIII
 

Yes, I will shim the servo when I drill for the mounting screws. I use a small piece of 1/32 inch a/c plywood placed between the servo and the ply hatch for a spacer. I also use the same shim when I locate the servo mounting blocks - I place the shim between the servo and the mounting block (I do this on both ends). This gives enough space around the servo so that the case doesn't touch the mounting blocks or the plywood hatch.

Sometimes I drill and pin the mounting blocks and sometimes not - I haven't yet on this plane but I might.

We can only hope that Greg will wear them - I think the kids will enjoy the show!

RE: Eindecker EIII
 

That's all I need at Wings for Kids...a grown man running around the field in his PJ's wear a mask. Don't I have enough trying to keep WWI planes out of the trees? Oh well, it's always a good show thanks to you guys!

RE: Eindecker EIII
 

Tim does That mean we all have to dress in cotumes ? It really is for the kids !

RE: Eindecker EIII
 

Billy if you can dig up that old Big Bird outfit and I'll bet HPA still has an original pair of Barney PJ's.

Well we digress...sorry Art there was a lull in the action.

RE: Eindecker EIII
 

Yeah, cmon Art put some stuff up here!
Doc

RE: Eindecker EIII
 

I don't have time, Doc.......I'm trying to figure out what costume to wear at the Wings for Kids charity event in Louisville :)

RE: Eindecker EIII
 

On second thought, maybe I should post something.......

Ok, after some field testing and lots of discussion, I am replacing the original stab with a new sheeted stab.
I am using 1/8" balsa sheeting top and bottom with an inner structure of 3/8" balsa sticks.

I am using the trailing edge from the original stab - it is hardwood and will add a lot of stiiffnes and strenght to the stab. I will also back up the leading edge with another piece of hardwood stick.

I think the elevators will also be restructured in the same fashion, using only balsa wood.


The first step is to edge glue some sheet stock together.

RE: Eindecker EIII
 

adding the trailing edge and other perimeter edges.......

RE: Eindecker EIII
 

Not to second guess the more learned and experienced, but I'm curious as to why the sheeting method won out over perhaps using a carbon fiber tube leading edge (and perhaps spar) on the stab? It seems like it would be lighter.

And regarding Sir Emerick and the turtle suit.... add a "pocket protector" and he'll be unable to resist. ;)

RE: Eindecker EIII
 

There are many ways to accomplish this task - and this is just one of them.

RE: Eindecker EIII
 

But 1/8" sheeting on a stab, 1/16' would have gone a long way toward stiffness.
Doc

RE: Eindecker EIII
 

I does seem like a bit of a "quick-fix" solution to the problem discovered during the first test flight. It was something that could be added immediately to have the model flying again the next week. Going the CF tube route would probably have meant re-designing the entire stab.

RE: Eindecker EIII
 

Basically it was quick and easy and I had all the materials on hand.......well if wasn't actually quick as nothing is quick for me - I'm just sayin'........

RE: Eindecker EIII
 

Turtle Report

I added the interior truss work to the stab and also the top sheet balsa. Then I weighted it down with all the heavy stuff I could put on [>:] ........I forgot to take a picture of the stab before the top sheet was added - so you'll just have to imagine a shot or two showing the balsa sticks arrranged in a multiple triangle type of arrangement.

I'll give it two days for the glue to dry - don't want any warping going on here [8D].

Signed,
The Turtle

RE: Eindecker EIII
 

Mr Turtle are you afraid the stab will fly away on it's own accord?

RE: Eindecker EIII
 

Well, yes I am......sort of. When I glued up the trailing edge to the bottom sheeting I let if set for a full day.......I came back to start adding perimeter pieces and found it in a badly warped condition. So I weighted it down and let it set for a couple more days.......fortunately, it finally dried and did so without any warps. So I am just heading off any future warp issues with this method.

RE: Eindecker EIII
 

Still waiting for the glue to dry on the stab...........

Meanwhile I am working on the tail skid. I choose half inch oak from which to cut the blank.
I think I will experiment with the router and see if I can get the edges rounded - might try a quarter inch round over.

If that doesn't work I will cut another blank and run it throught the planer to reduce the thickness.......

RE: Eindecker EIII
 

A decision to modify the wing and aileron tips has been made. The aileron tip will be cut off as well as the next bay (at least on mine). The tip will be glued to the wing trailing edge and the wing tip. This should make for a more pleasant look and provide more efficient lift at the tip.

This is but one man's modification........the designer is working on a new tip design which will be different than mine. Paul is also working on one of his own making.

Mine will have reduced aileron area and some might say will be much less effective.......it will be a little less effective, but I don't think the overall design will suffer much in the roll department. An Eindecker won't roll well anyway no matter how you ask it to........soooooooo -

RE: Eindecker EIII
 

Aileron tip is now cut off - no turning back now!

Chuck Cunningham's articles of design that were published in Radio Control Modeler back in 1976 or so called for an aileron area of 12% of the wing's total area for a sport plane. I haven't measured but it looks like this aileron is about 6 to 8 % of the total wing area.

I think with this plane a lot of rudder will be used for most of the maneuvering along with the ailerons..........I base this on how my old third scale E1 with wing warping flew and also on my observations of Paul's model. I think I'm gonna like it!

RE: Eindecker EIII
 

Good evening, just discovered your build, I am an old Eindecker builder.

If I may, I have an observation; as you are building a plane with a big wing, it has a lot of the same stresses that the full size jobs did. In looking at your wing, the two spars are some distance apart, which even with the shear webs will allow the wing to twist; when you have 40+ pounds hanging from it.

It is correct that the full sized planes used a goodly number of flying wires but they also internally braced the wings with diagonal struts that went from the top of each rib to the bottom of its adjoining ribs. From front to back, their were four of these X pattern braces between each set of ribs; this added a lot of internal stiffness to the wing. If when flying your prototype, it still allows the wing to twist, you might think about adding sets of X braces between the front spars and the ply sub spars and again between the sub spars and the rear spars.

My complements of your building skills

John

RE: Eindecker EIII
 

Hey John

Welcome to the thread. Thanks for the compliments. You are correct in your observations - design is a compromise and when one is working toward a sport flying type of model but using a scale outline and trying to work in as many scale features as possible - well, irregularities always pop up.

To control wing twist a D tube wing section and some trailing edge sheeting would have been the solution, but (and there's always a but) the decision was to preserve the flavor of the original Eindecker and sheeting would have spoiled the look so the deviations from scale begins.
Where does it stop? I guess where ever the designer or builder choses to stop.

It is definitely an entertaining excursion - the trip down the road of design. Designing for one's self and a "one of" model just about anything is acceptable. But when designing with the long range goal of kit production many factors need to be considered - time and money being the most important to production........and ease of building and flying being the most important to the consumer.

A good friend and I are in the beginning stages of a half scale Eindecker EIII project and much of what you mentioned will probably be incorporated into that design/build.

I have run on far too long........thanks for stopping in and I hope you stay with us.

Cheers,
Art

RE: Eindecker EIII
 

I'm not sure what you mean by "diagonal struts." The original EIII (the ONLY surviving original EIII) in the London Science Museum, absolutely does NOT have internal bracing struts. Perhaps you are referring to the span-wise criss-crossing FABRIC tapes which served to hold the ribs in position as the covering was tightened. These fabric tapes were also found on later Fokker aircraft (such as the DrI) and are still used today of many modern fabric covered aircraft wings. Remember that since the original flew with wing-warping, a flexible wing was an absolute requirement.

As you can see in this photo, there were however, diagonal cable bracings that spanned several rib bays.

RE: Eindecker EIII
 

One wing tip on and awaiting final sanding.

Second wing tip fitted, fill in pieces rough cut.......tip & bottom sheeting glued and secured. When this is dry I will add the other pieces and ribs and cap strips.

Then I will cut and fit the aileron to the new space.

RE: Eindecker EIII
 

[:@][:@][:@][:@][:@][:@][:@]
Sorry Larry ...I still can not get my video loaded up!
I will keep trying

HPA

RE: Eindecker EIII
 

Did you fly it again?

Jim

RE: Eindecker EIII
 

Here are some of my "quick fix" up grades that Art and Larry discussed down at our last R&D fly-in last weekend.......

These 2 pics show the wind tip I made and bolted on......I think I still have a middle triangle brace to install[&:]


HPA

RE: Eindecker EIII
 

These 2 pcs show ONE of the ways you can make the tail cage assy.

This is kinda Arts and Larrys ideas rolled into one.........

I like this construction because it is EASY, inexpensive, STRONG........and did I say EASY???




HPA

RE: Eindecker EIII
 

Eindecker Design Update

My original thought with this design was to use a flat bottom wing with a 1 1/2" wing-tube.
This works fine but I had wanted the wing wires to be non functional. Without any sheeting on the wing there is just to much twist without functional wing wires.
Also the wing tips are not strong enough when a cross wind picks up one side and drives the other tip along the ground.

So a redesign has been done.

1. The new wing is the same overall size.
2. The airfoil has been changed to an under cambered airfoil.
3. 1" wing tube for ease of assembly.
4, Ailerons moved inboard one bay, 5 bays wide and 4" deep instead of 6" deep.
5. One piece wing tip braced back into the wing two ribs.
6. Wing wires are required.

I have completed the drawings for these changes and I have cut the left wing panel.
The new wing build begins today.

Larry

RE: Eindecker EIII
 

There certainly is a lot[X(] going inside the Eindecker wing, that's for sure! It is indeed and interesting plane to model.

RE: Eindecker EIII
 

Yes Jim we flew it again............[&o][&o]
This time it flew very well! I have a 12 minute go pro on board video and I have a full on the ground video...........still working on up loading[:@][:@]

I balanced the plane at your recommended 25% and I felt it was to sluggish on the controls and dropped some nose weight and was ready to take another flight when I noticed the electronic ignition pick-up screws fell out!..........that ended the day............[:o]

I feel very good about next weekend. I am hoping to get in more than 1 flight per day! LOL!

I am telling you Jim...the pressure that ART and LARRY put on you when you are flying...is incredable!
I can tell they are rolling there eyes behind my back....I can hear Art mumbling "he hasent flow straight and level flight yet!"
I'm just kidding ..........about Larry...............

Hope to see you at least one of our camp-in flys.............


HPA

RE: Eindecker EIII
 

Here is the new wing tip dry fitted together. The tip is one piece 1/8" Baltic Birch and I score the front where it curves the most with the laser.
There are tabs that slot into the double tip rib. The brace pieces in the rear are 1" wide Baltic Birch glued on the top and bottom of the tip that are tied back into rib 13.

Larry

RE: Eindecker EIII
 

I don't have enough glue left to build two more wing panels[X(]......so I guess I will have to plod along with the Mark I Mod II version of the wing panels.

I like what you have done, Larry. I think this is a nice improvement as well as being a closer to scale under cambered airfoil.

RE: Eindecker EIII
 

Turtle Report

The second wing tip has been fitted and glued up. The aileron has been cut down to size. After the glue dries on the tip I can clean up the edges and fit the re-sized aileron.

I did some more measuring and I calculate the new aileron area is approximately 6% of the total wing area. I don't think this will be noticeably different in roll response than what Paul's plane is....his aileron area is about 33% greater than mine and looks to be 8% or so.
It will be fun to compare the two planes and make in the field evaluations of each one and then compare them to Larry's version.

They all will exhibit adequate roll control and be much snappier than a wing warp system would.

(waiting on glue to dry)
Art

RE: Eindecker EIII
 

Larry, I'm so glad to see that you have redesigned the wing!!! :D :D :D This is the much more scale wing that your model truly deserves and I think you'll find that it will appeal to many future customers. And your design thinking is right on the money; if the model needs functional rigging (and really what 1/3 scale WWI model doesn't?) then you might as well have a scale wing!

VERY WELL DONE!!!

RE: Eindecker EIII
 

Larry, one question: Will you need to be altering the angle of attack?

RE: Eindecker EIII
 

Art, beg, borrow, or steal more glue!!! ;) At the very least, make plans now for being able to fit a pair of the Mark II wings later. On the Snipe prototype, I built the rudder three times.

RE: Eindecker EIII
 

Art,

I buy glue by the gallon.:)

Abu,

With this design I placed the wing tube back 6 3/4" from the leading edge which is just less than 30% of the cord.
The tube can now be used as a lifting point for balancing.

I am going to set the anti rotation pins for 3 degrees of incidence.

Larry