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-   -   SIG Four-Star 20 EP build (http://www.Wattflyer.com/forums/showthread.php?t=73396)

dgjessing 03-21-2014 12:58 AM

SIG Four-Star 20 EP build
 
I wanted to learn how to use "Monokote"-like covering, and I was curious about how model airplane kits have changed since the last time I built one, ~40 years ago.

Plus it's novel (and nice) to buy something made in Iowa instead of China :D.

I gotta say I'm really, really impressed with this laser cutting! All the parts FIT without any adjustment! Nothing like the old die-cut stuff. Remarkable :)

More as things progress!

Hawk570 03-21-2014 01:23 AM

I have one of these new in box. Im about 1/2 way through my current build and the four star is next in line. Good luck with it!!!

dgjessing 03-22-2014 12:57 AM

Well I've been gluing a lot of bits together:

http://www.wsukes.com/temp/DSCF3177.JPG

The wings and tail surfaces were all done with TiteBond. For the fuselage I've gone crazy and am using that new-fangled CA stuff. I hope it really works... :eek:.

I remain impressed with the quality of the kit. Every part has fit flawlessly so far, and the instructions are great.

gramps2361 03-22-2014 01:21 AM

That looks great, and you haven't lost your building skills.

I build a kit each winter, and I still have not bought a modern lase cut kit. All the kits are the old die cut ones. Knock on wood the dies must have been sharp on the kits I found at auctions, or on line.

kyleservicetech 03-22-2014 01:50 AM

Quote:

Originally Posted by dgjessing (Post 943251)
Well I've been gluing a lot of bits together:

The wings and tail surfaces were all done with TiteBond. For the fuselage I've gone crazy and am using that new-fangled CA stuff. I hope it really works... :eek:.

I remain impressed with the quality of the kit. Every part has fit flawlessly so far, and the instructions are great.

Yeah, I've also used CA stuff over the years. But personal preference is still that Titebond or similar yellow carpenter glue. Years ago, I weighed several pieces of balsa sheeting about 3 inches square. Then made "Plywood" sheets out of them, using both CA and Titebond. Amazing, after 48 hours, that Titebond sheeting weighed less than the CA. After the Titebond glue dried.

I also think that Titebond is a little stronger than CA, far less brittle, and more forgiving of slight gaps in the glued joint.

When you put sheeting over that wing, just lay a strip of Titebond over the ribs, and a matching strip of Titebond over the matching area of the sheeting. Then lay out the sheeting over the wing ribs, pin it in place, and let it dry for 24 hours. That Titebond will stay tacky for awhile when just laid in place. But it sets a lot faster when under pressure, as when clamps are used.

And, if you make a :censor: mistake with Titebond, just hit the joint with a heat gun, and after a minute or two, a dull knife can easily pry the Titebond glue job apart, to "Do it right". Do not try that with a CA joint. It won't work, and will stink up the house with who knows what kind of fumes.

Last, no fumes with Titebond! Titebond also sands much easier than CA.

dgjessing 03-26-2014 12:32 AM

More gluing together of bits has been going on:

http://www.wsukes.com/temp/DSCF3178.JPG

These balsa things are a lot more involved that foamies!

I have to confess a dirty secret about this build - it's going to be powered by a Fox .25 glow engine :eek:.

The kit is designed primarily for electric power, but they say you can do a glow engine instead... I'm going with the later :rolleyes:. I could continue to post about the construction and leave out details about the engine, or just shut up :concern:. I'll leave it up to y'all :).

gramps2361 03-26-2014 12:46 AM

Oh that poor thing I think you need to pack it up and ship it to me. I'll give it some loving E-power!:p>:D

She's looking good and yes the balsa is a little more work. Oh ya keep posting like to see how this turns out.

tobydogs 03-26-2014 12:56 AM

DAVE!!!!!:mad:you:censor:low down dirty:censor: slimy son of a gun! we are coming now to your workshop to do an intervention:(....i can only hope we're not to late. theres about 40 of us so put on the coffee and prepare for a long visit.:cool:[jk]


seriously....looks like a nice build you have going on there and i do want to see your Handy work with the covering. then install the servos,Rx and misc pc's......then build the battery compartment and brushless motor mount. if after that you still want to go glow.............[popcorn]

sidybee 03-26-2014 01:04 AM

man these guys are are bad about there electrics hahahahahahaha
im watching the build close by. i like balsa building..:D

dgjessing 03-26-2014 02:51 PM

All the other kids in my club fly both electrics and (the other kind) and I just want to see what all the fuss is about. They seem to enjoy making several trips to & from the car to carry all the required crap, commiserating over balky engines, cleaning the plane afterwards, etc., etc. I just want to fit in, you know? :rolleyes:

OK, that's all I'll say about the build from the firewall forward, but continue to post about the rest of it :).

thepiper92 03-26-2014 05:29 PM

What is this glow engine you speak of, I have never heard of such a contraption. Must be one of those noisy, dirty, and polluting things. They need tuning and can just stop working during flight, and as you watch the plane plummeting to the the soft, forgiving ground, you'll question why you didn't go for the quiet, clean, unfailing performance of electric. Nice build by the way, to me all the more reason to give it an electric system.

kyleservicetech 03-26-2014 09:32 PM

Quote:

Originally Posted by dgjessing (Post 943675)
All the other kids in my club fly both electrics and (the other kind) and I just want to see what all the fuss is about. They seem to enjoy making several trips to & from the car to carry all the required crap, commiserating over balky engines, cleaning the plane afterwards, etc., etc. I just want to fit in, you know? :rolleyes:

OK, that's all I'll say about the build from the firewall forward, but continue to post about the rest of it :).

LOL

At least with a firewall type mounting for your power system, you can still convert back to electric if you can't get your glow engine running. :D:D :D :D

dgjessing 03-27-2014 12:38 AM

Got the servo mounts worked out this afternoon:

http://www.wsukes.com/temp/DSCF3185.JPG

For the reason that can't be mentioned :rolleyes:, I need three of them in the fuselage, so I had to depart from the plans a bit. The plans show the elevator and rudder servos side-by side. Instead, I've put all three in a line on the right side, leaving plenty of room on the left for a battery. I'll be able to move the battery up to 5" front-to-back in order to help with getting the CG right. The elevator and rudder servos (towards the rear) are separated in height so the push rods won't interfere with each other.

In another departure from the plans, I've added reinforcing cleats behind the firewall (visible) and also to the landing gear mounting plate (not visible). I would have done this for electric power too...

The wing is almost done - just need to do the sheeting on the bottom. I'm probably going to run a strip of fibreglas in the center section, top & bottom. I've got all the needed stuff so why not, eh? :)

dgjessing 03-28-2014 12:04 AM

Well, I'm loving this MonoKote stuff! Started with the flat tail surfaces (easy) and (if I may say so myself), they turned out great :).

http://www.wsukes.com/temp/DSCF3186.JPG

http://www.wsukes.com/temp/DSCF3188.JPG

I've settled on the Mario Bros. guy as the pilot, and epoxied a 4/40 screw into him to insure that he doesn't get loose.

I got the hang of doing the balsa sheeting on the wing by the time I got to the bottom - it looks a lot better than the top :rolleyes:. The secret is to wet and bend the pieces before gluing them in place. (Notice the flat spots in the upper photo...). Live and learn, eh?

dumo01 03-28-2014 01:34 AM

Dave

The dark forces you have set in motion will have the trees at the end of the runway reaching for you. LOL

Looking forward to seeing it in the air.

dgjessing 03-29-2014 12:39 AM

Those trees don't scare me! :D

Covered the fuselage this afternoon - turned out OK. I think maybe I can do a half-way decent job on the wing.

My only problem with the kit so far is that (in my opinion) they got a bit carried away with light weight in the 1/16" thick balsa wing ribs. I've accidentally broken several pieces off of them in handling the thing, sanding & what-not. The couple of extra grams 3/32" or 1/8" ribs would add sure would make it easier to handle.

thepiper92 03-29-2014 01:03 AM

I really don't understand it either, I prefer thicker parts.Parts on the mountain models p51 were too thin, the p47 is much better, plus I sheeted the top and bottom, reinforced the middle. I gave the whole wing a good push and it's very strong. The trailing edges are strong too, nothing like covering warping things the second you heat it, and with solite to boot. The p47 won't be like this fortunately.

fhhuber 03-29-2014 02:27 AM

1/16 balsa ribs are standard even on the 4*60... You eventually learn to handle the balsa without breaking it.

There are times I have used 1/64 balsa and even split my own 1/64 square stock.

dgjessing 03-29-2014 09:47 PM

OK, all the major covering is done :)

http://www.wsukes.com/temp/DSCF3189.JPG

I'm happy with it, for a first effort. As always, my surface prep work could have been a lot better :rolleyes:, but it turned out OK.

Now on to all the fiddly bits!

gramps2361 03-29-2014 11:32 PM

Looking good and glad to see Mario finally gets a plane to pilot. Just make sure the windscreen protects him from any oily residue.;):)

dgjessing 04-01-2014 07:58 PM

Mario gets fully enclosed under the canopy :).

It's coming along:

http://www.wsukes.com/temp/DSCF3194.JPG

To do the hinge slots I got a (cheap) Du-Bro "Kwik-Hinge Slotter" (#216) and it worked quite well - $3.79 well spent.

Sliding the stickers around on Windex sure didn't feel right :eek:, but it worked.

On to servos & push rods & stuff :D

thepiper92 04-01-2014 08:04 PM

I found the slotter made hinge holes too thick, and hinges were very loose. Also the tool only works on center hinges, something I should have realized

fhhuber 04-01-2014 08:18 PM

The alignmnet guide does center the ninges... but you can use other methods to ensure the hinges are lined up for top or bottom hinging a control surface. EG a strip of hardwood 1/16 thinner than the ET of the wing/tailplane will have the hinge appx 1/32 below the top.

The slotting tools come in assorted blade thicknesses also. The thinner blade(s) is more appropriate for "CA hinges" and thicker blade(s) for some of the heavy duty nylon pinned (looks like a door hinge) hinges.

The GP electric hinge slotting tool comes (if its still made) with 2 sets of blades for thicker vs thinner hinge slots.

thepiper92 04-01-2014 08:25 PM

I used the thinnest actually and found it still was too thick. I resorted to using an regular blade. The guide will certainly come in handy for the rudder and elevator though.

dgjessing 04-02-2014 01:09 PM

The CA hinges that came in the kit were much thicker than others that I bought separately a while ago. The thick ones fit the slots well - the thin ones wouldn't have...


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