Dukester

My Feedback: (31)

OK, I know its not January 1 yet, so I guess I'm cheating a bit . But I really wanted to develop my Autocad skills also, so I'm giving myself plenty of time to get familiar with the software. Here's the results of my first night's work a top view and side view scaled, rotated and aligned. Feel like I actually learned something new, so that's a bonus.

My entry is the Fokker EIII. It's been modeled quite a bit, but it's still one of my favorites. Started with a 3 view I had from earlier. Planning for Norvel .061 and a 42" span with full flying rudder and elevator. No wing warping unless I get really ambitious, so I'll either have to add ailerons or dihedral.

Duke

flyinrog

My Feedback: (1)

What I can see looks cool but you gotta get rid of the black background, man I have a certificate in Autocad, from 4 years ago and couldnt draw a square at this point ,one of the benefits of ADHD , if you dont do it you forget it.......Rog

Dukester

My Feedback: (31)

Well, got back to work after the new year. Progress so far on the 3D model. Got the wings roughed out and the fuse sides roughed also. Need to rotate the fuse rear together some, then do the top and bottom. Decided to go for the scale wing with warping so will use multiple spars out of fairly light balsa.

Duke

Bipe Flyer

Wow, that'll be cool! How are you going to accomplish the wing warping?

Ragwing

My Feedback: (2)

Looks good Duke, it will be exciting to watch this project come to life. My only question is why 3D? It would seem to me that once you have modeled a part you would have to spend a lot of time constraining relations between parts, etc, then have the program project to plans, then you have to tweak the plans and on and on. I'm just curious, it's looking really sweet.

Derek

mclintock

My Feedback: (3)

Dukester-
For this project you may want to seek a copy of 'Flying Scale Models' Volume 6, number 46.. september 2003. www.flyingscalemodels.com
It's the Fokker Eindecker Special issue. Lotsa history and many three views. Plus a description of how the wing warping system worked with full detailed numbered cutaway diagram of same with all the other rigging too.
And being a proper british mag, has full sized plans, in this case for a geared 600 sized 60" e-III. Oh and there's a couple pages of every paint scheme done on the real ones, plus alot of history.
-clint

Dukester

My Feedback: (31)

Well, on the 3D thing, this project is as much me learning to use ACAD as it is designing a plane. I'm doing the main portions on different layers, so actually projecting it out for printing should be pretty simple.

Clint, I'll check and see if I can find that mag, but its getting near impossible to find the back issues of FSM anymore. I actually have a fairly good illustration of the wing warping linkage, so I think I can job that one up. The rest of the rigging will all be 'Duke' scale.

Bipe, the original EIII had a sort of bellcrank job on the landing gear posts which connected to the stick and the wing tips. Moving the stick moved the bellcrank which pulled the wing tips down. I think I'll probably go for the same thing. That's why I wanted to use smaller spars and more of them, so the wing would retain some flexibility. I'll have to be careful covering the wing to keep its shape and maintain some flex. For the undercamber, I think I'll cover it in strips running from the fuse to the tip. I'm not sure how I'm going to do the wing tip and haven't drawn it yet. I think I'll probably just wing it (pun intended) when I get to that point. I'll tie the line for the warping to the end of the TE stock.

Here is a good pic showing what I'm talking about with the warping linkage. This also helps to explain why the EIII had that apparently overdesigned landing gear structure. On a side note, this is not my pic but its apparent the guy who did it has a real gift for working with 3D modeling.

Duke

BMatthews

The landing gear only LOOKS overdone. When you consider that it's also the lower flying wire and control belcrank mount it's quite delicate but appropriate for what it does.

combatpigg

My Feedback: (3)

There is an old guy from around here who did one of these for an .074, it is a masterpiece! I should take a picture of it and post it here. His rigging is done with microscopic, hand made brass fittings, but I have seen neat rigging done by just looping the fishing string through 1/16" ply hard points that are part of the frame work and jut up through the covering. They have a tiny hole drilled for the string[s] to pass through, and a simple noose type knot is used. When you are satisfied that your rigging job is plumb and square, then the knots can be sealed with glue.

Andrew

Duke --

You might take a look at SpiderWire Fusion for rigging -- it has almost zero stretch, is less than half the diameter of monofilament of equivalent test and is tough as steel. I've been using 10 lb. test for 1/2A C/L -- .049 reedies only.

Dukester

My Feedback: (31)

I went to the spider wire fusion for my pull-pull lines on the Halfwit, it is great stuff.

Duke

Dukester

My Feedback: (31)

Well sometimes it just pays to ask around at the old LHS. Last Friday I was talking to the guy about finding some backplates for a couple of Cox reedies and he goes in the back and comes out with two complete Cox engines. Both in great shape, so I gave $10 for them. He also tells me he thinks he has some Norvels at his house that he's not using. Fast forward a week and I'm back in there and he pulls out a plastic bag with two Norvel .061s. One throttled revlite and one C/L pre-revlite. Gave $20 for the two and get them home and find out they are both AME versions. So very nice deal and I got to swap the old tired bigmig .061 on my Halfwit for a nearly new AME.

Ok back to your regularly scheduled program!
Duke

Bipe Flyer

It sure does pay to ask. I went into a plastic model shop and asked if they carried any R/C planes. The guy said that they didn't, but there was a box of model airplane junk that someone had given him. In that box I found a NIB OS FP .40, 2 brand new PeeWees with throttles, 1 used PeeWee and an brand new electric pump. I got the whole works for $50 Canadian.

Dukester

My Feedback: (31)

OK, more or less finished the plans. From here on out all additional work needed will be duct tape and bailing wire. Finished drawing up the 3d model except for the top fuse and wing sheeting. Also will need some crossbracing in the tail, but will add that as needed after the rear box is built.

First pic is the completed (ok semi-completed) 3D model.

Second is a zoomed out view of the templates sheets for the parts. I printed them on my inkjet and will take them into the office for laser copies, then I'll iron the laser copies down on the wood to transfer the outlines.

Lastly is a quick look at the 2D wireframe projections I used to print out the plans to build from.

Hopefully will start making some scrap this week.

Duke

av8rsodt

My Feedback: (23)

Went to the NW Expo yesterday and was in awe of the Proctor kits. The EIII they had there in bare bones was impressive - can't imagine covering something so nice.

Looking forward to seeing a 1/2A EIII

Brian (Av8rsodt)

Dukester

My Feedback: (31)

Me too....

Actually, I did start on the wings. I cut out the ribs and use 1/8 x 1/4 balsa spars with 1/4 hollow fiberglass pushrods I had for the leading edge. I was thinking hard about wing warping until I got the everything glued and the wings are way too stiff for warping (which I guess is both a good and bad thing). So I have decided on a sort of a seamless aileron to mimic wing warping. First I need to laminate some wing tip forms and sheet the wing. Then I'm basically going to trim all the ribs along an angle under the wing to make a flexible hinge line. Not sure how I'm going to reinforce it right now, but I guess it'll come to me by the time I get there.

I also got the fuse templates ironed on to the wood and stripped some 1/8 sheet into strips for the tail section. Need to start the fuse soon.

I'll take some pics when I get the wing to a more finished stage.

Duke

Dukester

My Feedback: (31)

Wings are mostly framed up but I still need to laminate the tips. However, I did get the fuse framed up and cut out the tail surfaces. Here is my first bare bones pics. Starting to actually resemble an airplane. Weight at this point is 3 3/4 oz for the wings/fuse/tail feathers so it's working up pretty light so far.

Just for an estimate, if we make the frame 12 oz covered with landing gear, then add 5 oz for radio gear then another 5 oz for engine and tank, then maybe I finish up at 22 oz. So with an 8 1/4" chord and 40" span I have 22 oz over 2.2 sq ft of wing for about 10 oz/sq ft. So worst case scenario is its not exactly a floater, but not overly heavy. However, more realistic numbers are probably 10 oz airframe + 3.75 radio + 3.5 engine and tank = approx 17.5 oz all up for 8 oz/sq ft.

Duke

Dukester

My Feedback: (31)

I got back to work on the EIII this weekend.

Got the main fuse framing to my liking and installed nylon bearings in the tail for the flying rudder and elevator. Also installed push rod guides as I gave up on pull-pull. Covered the rear of the fuse (not my best job ever) and installed the rudder and elevator using 1/8 CF tube as the axle for both thru the nylon bearings. Very neat and tidy if not pretty. Also installed the thin walled aluminum tube for the wing to slide into. After that I went ahead aond covered the fuse.

I also tried to cover the undercambered wing bottom and after wasting a large piece of covering I realized its not going to be easy. I also realized that I don't have a second roll of the antique Solartex like I thought I did. So I have to order another roll from BalsaUSA as the LHS doesn't stock it anymore...... Decided to give up on the full on wing warping as I couldn't get a stucture compliant enough without sacrificing too much strength. So in the end I decided to use faux warping. I created seamless ailerons for the wing that are integral into the wing tip. Basically I used a line of CA hinge material under the sheeting and trimmed the ribs along an angled line to allow the flex. I also need to build up and sand the wing tips for a more pleasant surface to cover.

What I am happiest with at the moment is the scale-ish landing gear. I used 1/8 CF tube and some small cotter pins to make up a functional sprung landing gear. I have the mechanical stuff worked out and put everything together just press fit to check it out. Next step is to glue everything together permanent. Where you see straight wire pieces (the wheel axles for instance) they are simply 2-56 threaded rod into the CF tube. I also made up a tiny little aluminum bracket to connect the vertical link to the axle tube to the drag link. Its not a machined masterpiece as I made it with a pair of snips and a file, but its works great. I still need to add the spring mechanism (going to use hair bands I stole from my daughters), but the biggest part is done.

Still have the cowl and cockpit to do also, but they will be last.

Duke

Ragwing

My Feedback: (2)

Sweeet! It all looks great but I especially like the landing gear, you have good reason to be happy with it. Excellent work.

Derek

Dukester

My Feedback: (31)

Well, no new picture yet, but I did finish covering the wings. Ended up using some Monokote flat on the wing bottom. Looks bad, but its on to stay and didn't pull free when shrinking. The MK flat is a fair match and the tops of the wings are done with the remaining Solartex to match rest of plane exactly.

So now that its covered, I weighed it and I'm at 11 1/4 oz for the covered frame with the landing gear. I've got 2 1/8 sq ft and if I want to stay down in the 8-10 oz range, I figure I have about 9 oz to work with for the remainder.

So say:
norvel .061, mount, tank, firewall = 3.5 oz
350 mah nimh battery = 1 oz
RX and 4 servos (bluebird 371s) = 2 oz
Cowl = 2 oz

That should be flight ready I hope at 20-21 oz AUW.

Duke

Dukester

My Feedback: (31)

Well, I managed to get it to a flight ready stage. Its a big plane, coming in at 24 ounces on 2.125 sq ft of wing. The semi-wing warping takes some torque, so I ended up with a standard size servo as I kept stalling the small ones at larger deflections. Also, the Norvel .061 doesn't carry the same mass as a big rotary, so in hindsight I should have lengthened the nose by a few inches to help with the balance. As she sits she's got 2 1/2 ounces of lead in the cowl to balance her out. 24 ounces is definitely within the Norvel's ability especially with the big wing. It should handle quite scale.

Didn't get any trim work done on it yet and I managed to iron in a small warp on the fuse which I need to work out. But all in all, it's done and ready to fly. We'll see how it goes.

Duke

Japanman

Way cool Duke!
The wing warping sounds interesting- I bet it is a bit of a mission to get it all rigged up.
Looking forward to hearing how it flys!

J.M

Bipe Flyer

The cowl sure looks realistic. I can hardly wait to hear about the flight report.

Dukester

My Feedback: (31)

Well guys, variable winds at 15-20 so no maiden today. Even though the 30th is here maybe I'll still get it in tomorrow.

Duke

Dukester

My Feedback: (31)

Well, good news and bad news today.

First off, I did finally get around to doing my maiden flight. The .061 was humming along and even with the small prop clearance I had pretty good acceleration. After doing a few taxi tests to see how the ground handling was (small rudder with fixed tail skid, you can guess how the handling was) I lined up on the runway. Got her rolling fairly straight and got the tail up. After about 70 ft I got off the ground and started a shallow climbout. Seemed to be flying relatively straight as I was holding in just a bit of left aileron and some down elevator. After getting up about 50 ft, I started a turn and learned my first important lesson about wing warping and small models, namely that its not all that effective. I did manage to get it turned around and I was able to trim out the left aileron and down elevator for more or less level flight. So far so good and its just a bit twitchy on the elevator as the initial CG was a bit of a guess. I made one more circuit around when I had the first problem.

As I was flying the back leg of the pattern, the plane suddenly developed a desire to bank right which I couldn't control fully with the ailerons. I managed to get it more or less level with aileron and rudder, but I was heading out over the trees by this time and was only up about 40 ft. I tried to make a shallow banking turn, but ended up losing it in the turn as I couldn't control the roll. I got it pointed down and managed to partially pull out, but the end result is I pancaked it in. Damage was moderate, including a torn out firewall and shattered rear fuselage from the TE back to the tail. Looking at the wreckage, the crimp loosened up on the line running to the right wing tip. I had set it up with both wing tips flexed down slightly so that when the servo pulled one tip down, the other would relax up some small amount. When the line pulled out of the crimp, I lost the ability to flex the right wing tip and lost my roll control.

Anyway, not the end of the world and definitely not a bad first attempt at a scratch design. I'll put it on my bench behind a few other things and tackle the fuse repair when I get some solartex antique to match the covering. I'll probably also do a flat airfoil for it as the wing warping is leaving a few things to be desired.

I had a great time working on this though. Already looking forward to next years contest.
Duke