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Author Topic: Eindecker 24" scaled from Sterling plans: some questions from a newbie  (Read 1905 times)
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strat-o
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« Reply #25 on: November 06, 2017, 03:51:47 PM »

It looks like the wings have no dihedral. Is this observation correct? I would expect flight instability in this case.

See posting #16.  No discernible dihedral (from the image), but reported to be quite stable.
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tubegeek
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« Reply #26 on: November 07, 2017, 12:55:54 AM »

No dihedral as built so far. I'm expecting to make adjustments in the trimming phase to incidence and - if needed - dihedral also.

Working on the cowl and dummy engine now - not much to show yet, these are coming slowly/one step forward/one step back. Engine is going to be very simple, soda straw cylinders on a balsa engine block. I may or may not add thread 'cooling fins' to the cylinders: it seems like a lot of picky detail work that might not even look so great once it's done.

The cowl may be card stock over balsa formers, I couldn't get 1/32" sheet to bend neatly around that radius.

Some parts are coming together really well, others are proving more difficult.
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danmellor
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« Reply #27 on: November 07, 2017, 02:42:27 AM »

There is a little dihedral on the Aerographics version. I can't remember exactly how much without digging the plans out, but it's not a lot.

https://www.youtube.com/watch?v=xkvn6Bg8Wp8

That's the only flight I have. An early trimming flight indoors.

Cheers,

Dan.


   



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billdennis747
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« Reply #28 on: November 07, 2017, 03:14:02 AM »

The cowl may be card stock over balsa formers, I couldn't get 1/32" sheet to bend neatly around that radius.
I don't understand that. You are going with the grain?
I've built four Eindekkers of different sizes and - outdoors - they all flew well but with a very small amount of dihedral (like 1 degree) in flight
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ZK-AUD
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« Reply #29 on: November 07, 2017, 03:39:19 AM »

No dihedral as built so far. I'm expecting to make adjustments in the trimming phase to incidence and - if needed - dihedral also.

Working on the cowl and dummy engine now - not much to show yet, these are coming slowly/one step forward/one step back. Engine is going to be very simple, soda straw cylinders on a balsa engine block. I may or may not add thread 'cooling fins' to the cylinders: it seems like a lot of picky detail work that might not even look so great once it's done.

The cowl may be card stock over balsa formers, I couldn't get 1/32" sheet to bend neatly around that radius.

Some parts are coming together really well, others are proving more difficult.

try using the bendy bit of the straws that have the flex section

built in cylinder fins. 
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Jack Plane
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« Reply #30 on: November 07, 2017, 07:25:26 AM »

There is a little dihedral on the Aerographics version. I can't remember exactly how much without digging the plans out, but it's not a lot.

https://www.youtube.com/watch?v=xkvn6Bg8Wp8

That's the only flight I have. An early trimming flight indoors.

Cheers,

Dan.


Excellent flight Dan!  Before my time of course, but sorry to hear of its premature demise!

You know what question I'm now about to ask, don't you....?

.

.

.

.

.

What did you power it with?  Cheesy
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tubegeek
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« Reply #31 on: November 07, 2017, 07:22:58 PM »

The cowl may be card stock over balsa formers, I couldn't get 1/32" sheet to bend neatly around that radius.
I don't understand that. You are going with the grain?

Uh oh. Duh. That must be the problem. But that means I'll have to edge-join some sheets to get all the way around, right? Of course it'll bend better with the grain going fore and aft! I had the grain running around the circumference and the strips were cracking, even though only 1/32.

Thanks! That was kind of obvious in retrospect (but not in plain-old-spect.)

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I've built four Eindekkers of different sizes and - outdoors - they all flew well but with a very small amount of dihedral (like 1 degree) in flight

OK - what behavior should I look for on my trimming flights that will indicate need for dihedral?

What plans/kits/formats were they? This will be free flight/rubber power. There really isn't anything related to the Sterling kit anymore - basically I'm using the Aircraft Profiles pics scaled to 24" wing span size as my plans.
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tubegeek
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« Reply #32 on: November 08, 2017, 03:34:46 PM »

I don't understand that. You are going with the grain?

billdennis747 - thanks for that. As you might imagine, much easier time of it this time.
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tubegeek
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« Reply #33 on: November 18, 2017, 05:52:44 PM »

Here are some more progress shots, not much to report: a lot of one step forward, one step back, sanding through small parts and replacing them, re-doing tissue, etc.

I spilled the last of my Aero Gloss - that stank in more ways than one. So I guess it'll be Krylon Matte Clear for the remaining surfaces. That will be compatible with the Aero Gloss, right?

I did *finally* come up with a trimmable, lightweight attachment for the tail surfaces, which had been eluding me. I'll show a closeup oince I get the back end all finished up.

Fun project.
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Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
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tubegeek
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« Reply #34 on: November 28, 2017, 09:12:48 PM »

This part is fun.
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Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
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danmellor
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« Reply #35 on: November 28, 2017, 09:50:42 PM »

Looking good! On my Aerographics Eindekker, I had the tailplane halves joined by a piece of carbon rod in a paper tube. This gave easy incidence adjustment and was glued solid once trim had been found.

Dan.
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strat-o
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« Reply #36 on: November 29, 2017, 12:05:42 AM »

Looking pretty good!  I'll be interested to here how trimming this for flight goes.  Even though there's no dihedral, there are a couple features of this design that will aid in stability: 1. The large flat wheels close to the fuselage and under the wing will help cause the plane to bank in a desirable direction if it gets skewed in flight.  Also I think that the trapezoidal planform of the wing will have a similar effect to yaw the plane when it gets skewed in flight.  The trapezoidal wingtips, I think, will behave like a swept wing.
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ZK-AUD
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« Reply #37 on: November 29, 2017, 01:11:04 PM »

Mate you'll be interested in this - the Australian Vintage Aviation Society has built an authentic replica EIII complete with rotary engine.  Plenty of construction photos and videos on their website - Enjoy!   http://www.tavas.com.au/fokker-eiii.php
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tubegeek
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« Reply #38 on: November 29, 2017, 01:27:41 PM »

Thanks to all for the info and interest. ZK-AUD : The TAVAS plane is a beaut, and seeing it fly gives me hope! Thank you!

I've added the promised tail photos as well as a side-on view. You'll see that the tissue above the wings has been removed until I can finalize the incidence adjustment.

The tail attachment is via a small bamboo "fork" which slots into a bamboo crosspiece at the rear end of the fuselage. The fork provides location and adjustment of the rudder. The stabilizer can be angled by wedging or sanding the area that the fork slides through, which is a gap between two halves of a split bamboo skewer. The skewer connects the two halves of the stabilizer and is a friction fit onto the little fork.

The rudder is also located via a pin that goes up into it through the tail skid. All in all, a good compromise for me between weight, scale appearance, and some range of adjustment.

Balance-wise, with prop & rubber, the CG is JUST behind the main spar, so I can add some nose weight to address that when I trim-fly it. I killed two birds with one stone: I drilled out and attached a metal nut to the front of the dummy motor to provide a sturdy flat spot for the prop thrust bearing to slip into, and that was enough weight to bring the CG about 3/4 inch forward from where it was before that. I have the cavity behind the plug that the dummy motor attaches to, perfect for adding a bit of weight up at the nose. And the plug itself should be able to be angled a bit to provide thrust angle adjustment.

This will be trimmable once I find some decently tall grass around here - but that's a problem! I'm in Brooklyn NY and all the decent-sized open grass areas are mown short for ballfields.
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Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
Re: Eindecker 24" scaled from Sterling plans: some questions from a newbie
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tubegeek
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« Reply #39 on: November 29, 2017, 07:23:37 PM »

I tried to make him look very German and very WWI. And kind of mean. I haven't got any of his clothing worked out yet (except I painted stripes on a strip of paper towel for a scarf) but I decided to see what he'd look like painted anyway.
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knapster
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« Reply #40 on: November 30, 2017, 02:53:57 PM »

He looks a tad bit like our Russian buddy Putin....except he's wearing a shirt!
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ZK-AUD
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« Reply #41 on: November 30, 2017, 03:56:21 PM »

Be careful - Putin doesn't like those comparisons.  I recall reading that he became upset when he was lookaliked with Dobby the House Elf from Harry Potter
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tubegeek
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« Reply #42 on: November 30, 2017, 09:45:15 PM »

I'd like to see Putin mounted on a screw in similar fashion. I'd even give him a sock if that would get it done.
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cast_off_vortex
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« Reply #43 on: December 03, 2017, 05:50:42 PM »

Quote
He looks a tad bit like our Russian buddy Putin....except he's wearing a shirt!

Yes. That would look good in an I-16.
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