Well, couldn't pass up this deal so I went and bought a Goldberg Decathlon ARF. Have always eyeballed it anyway . Already started to build, and am very pleased with the quality of this ARF. The only downside was that the covering was wrinkled, but isn't that the case with most of today's ARF's ? Oh well, nothing a iron and heat gun couldn't take out.
Even though everything looks pretty simple, I do want a couple of opinions from guys who have build this plane before I make any mods or screw up :
I am planning on using a four stroke OS 120 Surpass pumped engine. Has anybody build a Decathlon with a 120 ? How does it balance ? Do the servos (or maybe just the rudder one) need to be moved to the tail in order to achieve balance ? I will mount my engine inverted instead of the suggested side mounting.
I was planning on modifying the struts too and insert a blind nut in the fuse for a better and easier support of the wing struts underneath the fuse. Anybody modified the struts ?
What pushrod system did you guys use ? The one supplied ?
Any other modification needed or recommended ? Any other tips or comments ?
Thanks

Built mine with a Saito 1.20. I mounted the engine inverted. I hated to cut the side of that nice glass cowl!!!! I cut out the original servo tray so I could run a servo for each elevator half (CF pushrods), and ran kevlar pull-pull on the rudder. You WILL NEED to attach the aileron servo mount blocks to the hatch cover with servo screws. DO NOT trust epoxy on this attach. I didn't fool with the wing struts. The attchment is too flimsy. Mine flew like a big ol baby at half throttle, and became fully aerobatic at full throttle. Plane glides nicely on approach. I had to restripe mine, all of the striping came off while I was shrinking the covering.

Thanks for the reply. I was thinking of having dual elevator servos too. Did you cut the servo tray completely out, or did you just add another servo on the other side ? I think I can just probably add a servo and then run another pushrod too. I also like those CF rods with steel ends.
I did reinforce the mounting for the blindnuts at the wing support. It just seemed to weak at that spot. No problems with the stripes coming loose on my covering. I will also paint the windows from the inside. Just don't like the looks of an empty cockpit where you can see all the servos and cables. Really wouldn't like to have to add additional weight of having to build a cockpit.

hmmm.... I am surprised of the lack of replies. Doesn't look like it is a very popular ARF.
Quality of this plane is pretty good though so far, and it looks like it might be agood flier with the Surpass 120.
Any comments on it's aerobatic flying characteristics ? What will it do ? I know it's not a 3D plane, but am still hoping it will do some nice maneuvers.

Did an all new servo tray. Rudder servo in the center, with each elevator servo on both sides. I used a mini servo for the throttle--made a separate servo tray for it too. Plane flies very nicely, and will hover. Very nice plane. Do a search for the GB Decathlon--you should find plenty of threads on it. The only bad thing about the plane is its flying wires. THEY NEED TO BE REPLACED OR STRENGTHENED!!! They are very weak. Don't bother trying to fly the plane with the wing struts on. THey WILL flutter themselves off.

OK, Decathlon is now closed to being finished. Had to finish some other projects first, but finally found the time to finish this baby. 2 elevator servos and modified wing struts.
What did everybody use to glue the plastic windows in ? How about the front windshield ? What holds the plastic best to the covering. The side windows are glued to wood. I painted the windows on mine black btw. Looks very sharp. Just need to glue them in now, but am unsure what glue to use on this one ? Regular canopy glue ?

texas - 3D great plane you will like the decathlon . for installing windows & windshilds i use clear silicon . it bonds very good to everthing & drys clear. works graet . GOOD LUCK BILL WRC-FLYER

Ok, it's finished. Was able to run the engine yesterday but the wind was so intense and gusty that I didn't want to risk it. The field is also flooded, so in case I had to land with a deadstick I most likely would have had to put her down on water if not being able to make the runway.
Anyway here she is. Included some decals to make her look more aerobatic . I also painted the windows black with black metallic testors paint so you don't see the interior (servos and wires). Looks very nice IMHO.
Setup is:

-Ailerons : JR 531's (2x)
-Rudder : JR 531
-Elevator : JR 537's (2x)
-Throttle : JR 537
-Battery : JR Extra 6V 1100mah (sitting in the tail for balance. CG at 4") w. Cermark 6V regulator

-Engine : OS Surpass III 1.20 pumped with Sullivan remote glow connector.
-Tru Turn spinner with Graupner 14x7 3 Blade prop.

Final RTF weight is 10 lbs 2 oz, so I think the OS 1.20 should fly her nicely.
Hope you like it. Flight report to follow soon.

well, have now about 10 flights on this puppy, and all I can say is that I absolutely love it. No bad habits at all, and the OS 1.20 Surpass is plenty of power. Not unlimited, but that might be due to that 3 bladed prop I am running. It doesn't need unlimited vertical anyway. Will try a Master Airscrew 14x7 3 bladed next. Just to see the difference between both props.
KE is nice when kept slow. If to fast it has a lot of coupling. Not impossible, but a lot of corrections are needed.
Landings make you look so good . It doesn't float forever, but is very easy to land. This plane has a lot of rudder authority. Takeoffs are pretty simple too. Being easy on the throttle let's it track straight down the runway.
I think I might still be a tad nose heavy, so will experiment a little with more aft CG.
So if you have ever thought about buying one, go for it. Trust me you won't be disappointed.

I have a goldberg decathlon new in box if anyones interested? The cowl has been cut for a 90 4stroke but otherwise complete and unbuilt. I just put it up on ebay. Sorry I didnt see this forum sooner and I would have offered it here first. I think I listed it for $250.