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Post  getback Sun Apr 26, 2015 1:44 pm

Here you goo  Scorpion - Simple trainer build - Page 2 Image110  Scorpion - Simple trainer build - Page 2 Image111  Scorpion - Simple trainer build - Page 2 Image112  Scorpion - Simple trainer build - Page 2 Images10
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Post  KariFS Sun Apr 26, 2015 1:51 pm

Thanks Eric! That Bruce Lee fellow may be on to something lol!

The pics showed the right side up on my iPad, but after hosting&posting they were upside down. Did you just download, flip and host them (that was what I was about to do) or was there magic involved?

I'll just steal those pics and attach them to my previous post.

Thanks again.


Last edited by KariFS on Sun Apr 26, 2015 2:00 pm; edited 1 time in total
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Post  getback Sun Apr 26, 2015 1:55 pm

Yes no Magic and they look really good man my computer is running so slow took a while and forgot to say something lol! Looks like your about to go Flying Flying bounce
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Post  KariFS Wed May 13, 2015 2:08 am

Some progress with "the Boy": I decided to paint only some red trim and leave most of it to wood colour. I was too lazy to do the scallops to the wings as per original kit and took some artistic liberties with tail feathers and cabin design too.

The wheels are held on with soldered washers, still have to dremel off some excess wire. Control linkage needs to be built too, and the motor mount is not yet attached properly. But other than that, it's pretty much done. Right now it weighs 150g or 5.3oz. CG is a little too far aft, it is right at the edge of the red area on the wing. I'll see if an extended-tank Bee with a muffler is enough to move the CG sufficiently.

I have a question: Should I add wingtip weight and if so, how much? I have a small jar of U.S. pennies, should I add one or two? Smile

Here's a couple of pics:

Scorpion - Simple trainer build - Page 2 Image210

Scorpion - Simple trainer build - Page 2 Image211

Scorpion - Simple trainer build - Page 2 Image212







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Post  roddie Wed May 13, 2015 11:27 pm

KariFS wrote:

I have a question: Should I add wingtip weight and if so, how much? I have a small jar of U.S. pennies, should I add one or two? Smile
Scorpion - Simple trainer build - Page 2 Image212


Hard to say how much outboard tip-weight would be adequate. Once your lead-outs are installed, you'll have a better idea. Are you planning on running your main-lines through the guide and attaching directly to the bellcrank? That would be the lightest weight to offset on the outboard wing-tip.

You could make a simple adjustable lead-out guide.. not necessary, but convenient. I've built "comb" type guides which are fairly simple and lightweight. It can help with flight-trimming.

Scorpion - Simple trainer build - Page 2 Adj_le10
Scorpion - Simple trainer build - Page 2 Adj_le11
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Post  CHELLIE Wed May 13, 2015 11:47 pm

KariFS wrote:Some progress with "the Boy": I decided to paint only some red trim and leave most of it to wood colour. I was too lazy to do the scallops to the wings as per original kit and took some artistic liberties with tail feathers and cabin design too.

The wheels are held on with soldered washers, still have to dremel off some excess wire. Control linkage needs to be built too, and the motor mount is not yet attached properly. But other than that, it's pretty much done. Right now it weighs 150g or 5.3oz. CG is a little too far aft, it is right at the edge of the red area on the wing. I'll see if an extended-tank Bee with a muffler is enough to move the CG sufficiently.

I have a question: Should I add wingtip weight and if so, how much? I have a small jar of U.S. pennies, should I add one or two? Smile

Here's a couple of pics:

Scorpion - Simple trainer build - Page 2 Image210

Scorpion - Simple trainer build - Page 2 Image211

Scorpion - Simple trainer build - Page 2 Image212








Very nice build Very Happy you will need outboard wing weight, install the lead out wires on the plane, then balance the plane so its neutral, place a t pin in the rudder and at the front of the plane in the middle centre line, balance the plane untill the wings are level, then add the extra weight of a Quarter to the outboard wing to compensate for the weight and drag of the control wires/lines. Thats what I would do. fly the plane and add or remove weight as needed on the outboard wing. a test flight will tell you whats needed, but you will be very close with the info I posted.
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Post  KariFS Thu May 21, 2015 10:59 am

roddie wrote:
Hard to say how much outboard tip-weight would be adequate. Once your lead-outs are installed, you'll have a better idea. Are you planning on running your main-lines through the guide and attaching directly to the bellcrank? That would be the lightest weight to offset on the outboard wing-tip.

You could make a simple adjustable lead-out guide.. not necessary, but convenient. I've built "comb" type guides which are fairly simple and lightweight. It can help with flight-trimming.

Thanks again Roddie. I already made a fixed lead out guide. My lead-outs are made from thin steel wire and the pushrod is steel too. I'll post some pics later. I bought some fishing lure attachment thingys for lead-outs for the other plane, the Scorpion, they are about 10" steel cables with loops and clips in the ends, tested for 40lbs.

That adjustable arrangement looks convenient, and it is certainly worth considering. My first two planes have fixed guides, positioned according to the plans. The one on the Scorpion is long enough so that I can drill more holes if necessary. The guides are pretty far back as both planes have a lot of rudder offset. This may hurt the performance but these are my first planes and I don't mind if they are a little sluggish, I just don't want them to turn in. My balance and coordination suck, I can't dance and I'm lousy at sports in general so I have to play it safe Smile

There's a good discussion about offset and counterweights going on in another thread, I have to read it through again a couple of times Smile
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Post  KariFS Thu May 21, 2015 11:08 am

CHELLIE wrote:
Very nice build Very Happy

Thanks, I am glad you like it Very Happy

Thanks for the info too. I didn't realize that basically you just need to make the balance even and then add some. I have to find my (incomplete) commemorative quarter collection and weigh some coins Smile For balancing I bought some zinc counterweights that are made for automotive alloy wheels, they are quite compact for their weight and have strong self adhesive tape attached. Been too busy the last few days to do anything productive with my planes but will report the progress as soon as something happens.

Thanks again Chellie Very Happy
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Post  batjac Fri May 22, 2015 2:56 am

Kari, that American Boy looks Awesome!  Great job!

On mine, I just put the leadout guide per the plans, and for the wingtip weight, I just glued on a nickel per the plans also.  An American nickel weighs approximately 47 grams.

Scorpion - Simple trainer build - Page 2 DSCN3563_zpsnm5eftts

Scorpion - Simple trainer build - Page 2 DSCN3562_zps7as3ibqh



The Conversion Mark
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Post  KariFS Thu May 28, 2015 3:00 pm

batjac wrote:Kari, that American Boy looks Awesome!  Great job!

On mine, I just put the leadout guide per the plans, and for the wingtip weight, I just glued on a nickel per the plans also.  An American nickel weighs approximately 47 grams.

The Conversion Mark

Thanks, glad you like it Smile

I tried to eyeball and even measure the lead out guide position but it seems that mine is further back than yours. I did eyeball the bell crank position too and maybe the bell crank is different size so... Lot of variables. But a wise man once said, "well, this ain't rocket surgery", I hope he was right Very Happy

By the way, I think the nickel weighs 4,7 grams Wink I'll see how ithe plane balances now that I have the control linkage built, but I think I am going to use one of my 5 gram self-sticking alloy wheel weights.

The Nit-Picking Kari


Last edited by KariFS on Thu May 28, 2015 3:42 pm; edited 1 time in total
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Post  KariFS Thu May 28, 2015 3:13 pm

OK, now the Scorpion is painted too. At first I thought I'll do a basic red over white scheme, and did, but it seemed a little plain. So I decided to add some racing numbers, inspired by Reno racers, hey they fly circles too Very Happy I picked number 7 because it's easy to cut the mask for it lol!

Still have to learn how to sew the elevator hinge, build the control linkage and dremel off the excess wire off the landing gear. I didn't have wheel collars so I went the nostalgia route and soldered some washers on to hold the wheels. The engine mount may have an unintentional upwards angle built in, don't know how that happened, need to check again and shim if necessary DAMMIT!

In the background of the second photo you can see one of the things I love most about summers in Finland, the photo was taken at 11pm and it's still not dark outside.

Scorpion - Simple trainer build - Page 2 Img_0011

Scorpion - Simple trainer build - Page 2 Img_0012
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Post  KariFS Tue Jun 09, 2015 3:30 pm

Practiced some hinge stitching the other day. First on two pieces of scrap balsa, then on the elevator of the Scorpion. I pre-punched the holes with a needle on 10mm intervals on the stabilizer, then the same thing on the elevator, with a 5mm offset. I used "Dyneema" fishing line as it is not supposed to stretch or absorb any liquids. Afterwards i put a drop of superglue in the needle holes. Here's the result, maybe a tad tight but not too bad.

Scorpion - Simple trainer build - Page 2 Img_0011

I also installed lead-outs and the bellcrank. I thought that the lead-out guide was long enough to allow some adjustment, but my bellcrank was bigger than I thought, and to prevent binding I had to drill the holes close to the ends of the guide. Overall the lead-outs point "in average" slightly aft. Hope it'll be OK. I had to make a little bend to the pushrod to adjust the length. It is difficult for me to get the bends precisely to the right places. I also need to learn how to make neat and sharp z-bends. Or maybe I'll start using some adjustable RC-style pushrod ends in my future planes. I checked for the balance and added 10 grams to the right wingtip.

Scorpion - Simple trainer build - Page 2 Img_0012

This thing is built like a tank and it came out pretty heavy. Last time weighed it it had 2 coats of clear, and it weighed 162 grams. Now, after the paint job, the balancing weight and controls the whole thing is 214 grams, that's 7.5 oz. Kinda heavy, no?

Scorpion - Simple trainer build - Page 2 Img_0013

The American Boy is also completed minus some nose weight, right now it weighs about 5.5 oz with its 5 gram wingtip weight and a short-tank Babe Bee.

Scorpion - Simple trainer build - Page 2 Img_0014

Flight report will surely be filed shortly after the maiden flights Airplane
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Post  Cribbs74 Tue Jun 09, 2015 7:48 pm

Kari,

I thought I had commented on this thread, sorry, I have been following.

Your models really turned out great. Do you have a PDF. Of the plans?

I really think with a different wing that Scorpion could be a neat little stunt model.

Ron
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Post  RknRusty Tue Jun 09, 2015 9:22 pm

That really is a good looking build, you can be proud of that plane. I like it a lot, really looks tough and capable. I'm a big fan of sewn hinges too. If you ever decide to add some engine offset, you can buy nylon shims for that job. They come in sets of 1,2, and 3 degrees.

For leadout weight, fly it and see. An observer outside of the circle needs to know how to watch while you fly low and flat. He/she should follow the lines and continue them as an imaginary progression of the line through the plane. If the outboard tip is angled higher or lower than that line, then adjust tip weight accordingly. That will have a big effect on the plane's stability in a crosswind.

Good luck.
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Post  NEW222 Tue Jun 09, 2015 10:37 pm

Wow. Those are great looking planes you got. You did a very nice job of building and should be proud. And if they were mine, well, lets not go there as I have a lot to learn in building....
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Post  NEW222 Tue Jun 09, 2015 10:40 pm

Forgot to add, I love the look of the hinges. I would like to ask is it just threaded from one side to the other and glued, or back and forth then glued?
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Post  KariFS Wed Jun 10, 2015 4:37 am

Thanks guys. I had a lot of fun building and painting these. Before this spring I thought the frown on my face was permanent but apparently not. Model planes and waterdog puppies (wife's hobby but I get to play with them) make miracles happen Very Happy

Ron, I also thought the Scorpion would look good with a built-up wing. I like the fuselage shape, it has some Mustang and some late-model Spitfire in it, very classic. I like to modify stuff and I already was thinking about "Scorpion II", maybe adapting the Ringmaster wing design or similar and then installing my Medallion (w/ a Black Widow cylinder) on it. But first I need to learn how to fly round and round with these two Smile The original plan was from Outerzone, there's a link to it earlier in this thread.

Rusty, thanks again for the tips. My son has already promised to work as a pit man (actually I don't think I could keep him away even if I tried Very Happy). I'll have him watch and/or video the flights. And maybe he can fly and I can watch. I suppose a little too much weight is safer than too little weight?

NEW, these were simple builds, not a lot of skill involved. I have built model planes before but it has been almost 20 years since the last ones before these. Profile planes are simple, cheap and fun to build and any suggestions are welcome Smile
The hinges are threaded in a "figure 8" fashion, first through one panel, then through the hinge line, then through the other panel, again through the hinge line and so on. I started from the middle of the elevator, worked to the left, and when I reached the end the hinge looked sort of like this (stole the pic from http://www.modelflying.co.uk/forums/postings.asp?th=37544 ):

Scorpion - Simple trainer build - Page 2 Stitched%20hinge

Then I worked back through the same holes towards the middle, over to the right end and then back to the middle where the ends of the thread met again and were tied together. So the entire hinge was made of a single length of thread. Kinda hard to explain but if you take a couple of, say, 4" pieces of 1/8" scrap balsa or ply, punch the holes and start threading, you'll get it. During the sewing the panels were held together and parallel by a binderclip in each end of the hinge line. After the hinge was complete, I moved the elevator up and down, past its normal operational range a few times to even out the tension (my stitching is not perfectly constant Smile ) and adjusted some parts of the thread so that it looked as neat as possible. Then some superglue in the holes, mostly to seal them against moisture and castor fog. The process was not difficult, maybe somewhat tedious but I like this method a lot better than fabric hinges. And I like the look of them too. It did take me an hour or maybe a little more to complete, including a few mistakes that required some un-stitching to correct.
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Post  NEW222 Wed Jun 10, 2015 9:03 pm

Thanks for the reply. It is very clear and answers my questions, thank you. I will have to give this a try on my next build.
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Post  getback Thu Jun 11, 2015 7:52 am

KariFS , Your airplanes look great and well done on the hinge stitching , mine didn't come out as well but I think I am going to stay with it for the cloth never again and the glass maybe but , I will get more practice for sure  . The color scheme is very nice ! Look forward to some video Very Happy Heres mine after I ripped off the cloth mess ....   Scorpion - Simple trainer build - Page 2 Stiche10 some how I even put the elev. horn mount brace on backwards confused and had to rip, grind that off and replace DAMMIT! . Eric
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