I'm going to build this plane, The Goldberg Extra 300 for a upcoming airshow/funfly and was wondering since its a older kit, would there be any intrest in doing a build thread on it.
I will do a few mods, but nothing to serious.

We're always interested in a build thread. And this is a fantastic airplane

Thanks Mike , I can't agree with you more about how great the plane is , I hope to always have one in my hanger myself.
With the instant gratifacation ARF world we live in now days , kits are not as popular as they once were.
I'll try to get started on this thing next week, providing I get my other chors out of the way first.

absolutly, I've contemplated building one of these for awile, and I love to see one go togeather!

Before you start the build. Why not give us the specs? What engine and servos? Are you buying a glass cowl or reinforcing the ABS? If i remember that far back it was a nice build. The ribs were a little thin/soft. But the rest was nice.

David

And if you would, you could make me a template of the parts, I have plans for it. {{I think!!}} If not I have built enough of them for friends I know where to get them. I never made the templates because I thought this was one of the kits that would never be taken out of production. Sort of like the CG Sukhoi, James, did you make templates????

Where I'm building just the covered and painted airframe W/O engine or radio to give away its a little tough giving the specs. I will use the ABS cowling and glass it inside with some 1/2-3/4 oz cloth and finishing epoxy also I will set the nose up for the heavier engine such as the 120 YS. I have a set of glass pants around here for it and will be doing away with the wire landing gear, for a set of dubro glass gear. I see fiberglass spec. has the alum gear for this plane and it would save a little weight if used over the dubro glass gear but mine seems to work fine, has a shock absorber effect. The rudder is going to be inlarged a 1-1/2 on the bottom and then taper up to the original size at the top if I remember right. I think I may do what I did with mine and make it a pull-pull set up on the rudder and a 2 servo evevator setup.
Since this is not a 3-D plane I won't be changing the size or shape of the elevators or ailerons any.
A set of templates is a good idea, I'll see what I can do about that little job.
I just need to make the time to get this project on the board.

I have the YS 1.20NC in mine, a perfect match!!! Even if you just trace the parts out on bond paper it's OK with me. Mine is getting a bit long in the tooth and I would like to build another one for myself, maybe make it bigger for a 40cc gasser?? Mine has no mods at all and is a perfect plane but I think I would like to make all the controls counter ballanced, no real reason, just looks better.

Gene, unfourtanatly I did'nt make tmeplates, I figured the suk would be around at least long enough to fly mine and decide if I wanted another or not but to late! GP bought out Goldberg and discontinued all of the kits that were compition for their arfs.[:@]

I'd like to snitch a set of templates to if I could please, I'm sure I can Find a set of plans on ebay or somthing!

[quote]ORIGINAL: bipeguy03

Gene, unfourtanatly I did'nt make tmeplates, I figured the suk would be around at least long enough to fly mine and decide if I wanted another or not but to late! GP bought out Goldberg and discontinued all of the kits that were compition for their arfs.[:@]

You noticed that too!![:@] Extra plans I can get but how many of us thought GP would kill off anything they bought that competed with there products?? Why make templates when you can always buy a kit. Everyone thought, Oh Boy, GP will start laser cutting these kits and improve them!! Sure they will.

Ok hold the phone what did I miss here, last I heard was that Lainer had bought Goldberg and the kits come back to the marketplace, then I see they just dissapeared off the face. I had a 2 ea Extras & 1 Sukhoi in the Box at the time and wasn't to concerned about this very thing, but this is my last kit.
I was a little upset when they didnt give the glass parts with the kits any longer and went back to the cheesy ABS, but aftermarket glass parts could and can still be obtained for these planes so again I wasn't to upset. But after reading this I am boiling and untill GP does something to ease my feelings on this matter they can keep everything they sell. They tried to monopolize the market back in the 90's by buying up anything that had wings just to get there name on it so nobody could kit cut one legally. I guess maybe they feel these old GB planes are so outdated that nobody will miss them WRONG!!!!!!!! They are 2 of the best flying planes ever designed and while I own and owned several GP kit planes there 60 size Extra while its a good plane won't hold a candle to the GB IMO. Sorry for the rant guys this sort of thing just gets me going. I have not heard about the ultimate is it on the list of no longer made list also.
I don't know (cause I haven't checked) but RCM or AMA may have the plans for these planes at a small fee + shipping.

Anyway this is a build thread so heres what I have so far .
I got a few mins last night and got the tail Feathers out of the way.
Its a fairly common build with 3/16x5/16 sticks covered by sheeting on the flying surfaces, and 5/16x5/16 stick built on the control surfaces, This makes for a very strong but light tail feathers. Note the added 1 1/2 inch I added to the rudder at the base. This really helps rudder control W/O spoiling the stock look of the plane to much.

The Saito 115 is lighter and smaller than the YS (great engine also) and gives as much if not more power. I converted my old GB 300 by removing the OS1.08 and installing a Saito 100. That amount of power is perfect for me. I dropped the weight down 17 ounces.

Pull pull on rudder is great. I used the belcrank system from Central Hobbies to give me two outputs to the elevators. It's mounted about 6-8" forward of the tailpost and is driven by a pushrod from one servo mounted forward on the supplied servo tray. This keeps the weight of two servos off the tail. A bit pricey but it's ball bearings and is really quality.

Some people have trouble with the light and fragile ribs and LE sheeting. That is part of the design and very necessary to get the wing light. The lighter the wing the quicker response time in roll. That is it will stop nearly instantly once ailerons are neutralized.

Legality aside plans can be copied at Kinkos. I'll bet some kit cutter would do a short kit.

I bought two more 300 kits this year off eJunk. I NEVER want to be without the GB300 in my fleet. The best aerobatic model I've ever owned. Also it's the first airplane I'll fly after an absence and rusty thumbs. Soooo easy to land.

Fortunately I have one flying and one in the box. I have tried the two servos in the rear for elevators, but it just adds to much weight. I also use the belcrank system from Central Hobbies, and like av8djc mentioned, pricey but a great quality product. I have the servos for the rudder pull pull and elevators mounted half way between the servo tray and tail for balance purposes. I'm running a YS(Z) 110 upfront.

It is a shame that these kits are no longer carried, all CG kits fly great.

Are you going to assemble the turtle deck as per instructions? Has anyone done this differently? Just gluing it to the outside of the fuse and doping it up with filler seems a bit strange to me. It probably works just fine, but.... it seems like an eye-sore just waiting to happen.

I did both my ultimate and my suk deck the way the plans show, and with a little time and patientce you can make the gap invisable under the covering. all though You could try to shave a few thousanths off the bulk heads, put a back-up stringer on the fuse top and edge glue it, choice is yours either way will be plenty strong and look fine!

James

Or just fly a knife edge every time over the run way and nobody will ever see it! As bipeguy said, use filler and blend and you will hardly see it.

I have built several of the extras and done the deck as per the instructions and just used filler and sanded to a taper. You can't notice it at all. It's not some big lip sticking out.

Wow. Thanks for the info everyone. I'll build it as is.

Did GP eliminate this kit? I just bought this kit from Tower last fall. I'll have to make templates if it is so.

Just as Grey Bread said build it as the book says they come out great on the turtle deck area. A little filler and sanding and your done. I use Dap fast N final Spackeling , I get it at WALMART.

The 115 Saito may be smaller and lighter than a YS, but it is no way stronger or as strong, even the horizon webpage says its bench marked prop was a 15x8 @ 8800 RPM's Ok so I run a 16x8 APC on my old 120 SF's and NC at 93-9500 a full inch longer at 800 RPM's more on 15% fuel. My 120SC which is in my GB Extra will turn that prop at over 10 K if I let it.
The 110 YS will swing a 16x6 APC at about the same RPM's i'm getting and is a much lighter engine. I'm not saying a saito isnt a good engine I have some myself, but there nowhere as powerfull as a YS is.

I used 2 servos in the fuse for the elevators not in the tail which worked out good. My total weight is about 8 1/2 - 9 Lbs with the stock pull pull and a 120 YS under the hood twin aileron servos , glass cowling and pants. The plane fies very light at this weight and floats coming in for a landing. I think that large prop may have alot to do with that. The 120 SC will take it straight up out of sight at a little over half throttle.
When I get some time I will get some Alum gear from Fiberglass Spec that should help even more to lighten things up.
The one I am currantly building now is the second one for the year. I got talked out of the first one.

[quote][It is a shame that these kits are no longer carried, all CG kits fly great. ]

Is this the same plane? [link]http://www.philshobbyshop.com/tek9.asp?pg=products&specific=jmosfnfpm[/link]

After seeing it discontinued on Tower (now I'm upset), I need to know, is there another canopy that fits this model? I'll be building more of these with templates, but I need a canopy.

......maybe I'll have to learn how to make my own! [sm=72_72.gif]

bigal126
Yes that appears to be the GB extra 300 and the price is right to.

Hi all I got some time and was able to get a fair start on this kit. Heres a couple pics of the progress so far. The wing builds easy but the ribs are fragil. I left only a opening for the servo wire to pass thru in the ribs, the rest I glued in place for added strength.

The wing almost builds itself, everything is already made for a person.
The wings like many are built upside down useing the left plan for the right wing.
You start out with a basswood spar on the bilding table ,then add 3 ribs 2, 6, and 10 which have breakoff tabs. After pinning these ribs in place you can then add the trailing edge and remainder of the ribs followed by the shaped leading edge.
The leadign edge calls for a 5/16 cutout for the wing dowel. I used a 5/16 brass tube sharpened to cut the half a hole in the leading edge which worked good.
After the leading edge is lined up and glued in place ,next comes the top basswood spar. this needs to be set by useing the step back gage supplied in the kit. This will put the correct dihedral in the wing .
The I added the shear webs which again are already made and fit on the front side of the spars from ribs 2 to 10.
Next edge trim three 3x1/16x36 sheets and glue them together. This the leading edge sheeting and must come out to the correct size when finished, so a little extra measuring will help here so the premade center sheeting will fit good. Next add the trailing edge. Complete the other wing up to this point.

After I added the center sheeting I also added the 1/16x1/4 cap strips and the tapered trailing edge. Useing a flex scale I marked the joint edge of the wing and trimmed it up even.
Next comes the fun part of joining the 2 wing halves. The kit provides some tip saddles and a couple center saddles that work ok, if your carefull.
After making sure the center joint fits good I set the wing in place and before I glued anything in place I used my incidence meter to check things out and make sure I wasn't building in any warps or twists. I had to raise the wing up to be able to do this and use the kit saddles.

After I was satisfied with the fit and 0 degree incidence through out the whole wing, I put the dowel support and lower no 1 rib in place. I then glued the center sheeting and trailing edges together using thin CA ,Make sure you have a sheet of wax paper or plan protector under the wing before you do this.
It takes a little trial and error to get a good fit on the dowel I have made it sound like it falls together ,believe me it dosent.
I then added the 2 center wing joiners useing 30 min epoxy I clamped it together to dry, but I also made a final check of the wing for straightness and twists.
After the epoxy had set up several hours I went ahead and installed the dowel support and both top and bottom half ribs and also the rear dowel support useing 5 min epoxy. I also rounded the front of the dowel before I installed it. I did this by putting it in a drill and spinning it while holding some 80 grit paper against it.
I did add the center ply but only for a strength factor this wing will have 2 servos.

Next I added the trailing edge sheeting while holding the wing down with weights on the saddles. Thats it so far maybe more today since its snowing ,Shakes my head.

More of the build if anyone is watching.
After making 2 more leading edge sheets, I held the wing down on the saddles with weights and glued them in place useing med CA , A person needs to do this rather quick before the glue starts to set up. So make sure your wood is cut to size and straight before you try glueing it in place.
After both side was done I added the last of the center sheeting ,end tip sheeting and the 1/16x1/4 cap strips .
I then removed the wing from the building board to inspect things and make sure of good strong glue joints all around, and added the wing tips.
Then the put the center fiberglass tape on the center section of the wing, I followed the instructions in the manual.

I then found the airleron stock and marked the center with a line running down the center of it ,I then marked 2 more lines on each side approx 3/16 down this is my ref point of where to cut the bevel to.
Useing the plans I marked the location of the hinges I used CA type hinges , Not the ones supplied in the kit.
I then used a exacto knife and cut the slots for the hinges making sure they were on the center line.
I then transfered the hing lines to the wing and cut the slots in it also. I then put the airleron on the wing for a test fit ,one side was good the other I had to move one hing slot just a tad to obtain center. After being satisfied with the fit of the airlerons I next built the servo trays.

The kit give you some trays ,but I don't much care for them so I make my own, I used 1/8 lite ply this time but 1/16 is plenty. I did use there balsa cover for a template which worked ok.
I then added some basswood sq. stock to the ribs for the servo tray to rest on and attach to. I then sheeted the rib bay on either side of the tray with balsa for ease of covering.
After some final sanding,to help contour the tray to the wing a little and knock off any high spots . I then drilled 4 ea 1/16 holes in the corner of each tray for the hold down screws, after drilling thru both the trays and rails I removed the trays and redrilled them with a larger sized bit for screw clearance.
Outside of some final sanding that completes the wing . I did recheck it with the incidence meter its not bad maybe 1/2 of a degree twist that will come out easy with the covering.

Wasn't that fun now comes the fuse after some cleanup to the workbench.

Oh I almost forgot ,make sure you build a left and a right servo tray they are different . The plane I made earlier this year I made two of the same and got told all about it *LOL*