Deadeye

So I've got a big black box in my garage with this plane in it. Was thinking of bashing it into a 3D machine. Was thinking a Saito 150 for power, and I would like some thoughts on the subject. I've never built a Goldberg kit, so any tips on building would be appreciated as well.

planebuilder66

My Feedback: (8)

Uh, those are now on the want list, seeing that they are currently discontinued, you might want to either build it and enjoy it, or just get something that's 3d right out of the box. I guess I'm now in disbelief that goldberg stopped making the ultimate, but all good things must come to an end, right?

MinnFlyer

My Feedback: (4)

Ditto. That thing is one of the best Ultimates around. Put a 91 - 120 on it and it will do anything except hover. It's an amazing airplane.

daveopam

My Feedback: (9)

It is a great airframe..a 3D airframe it's not. The Aile surface area is just way to small. Look for a Goldberg Ult build thread in this forum by TWN. He did do some mods to help with 3D.

David

Deadeye

So the general consensus is a no go for 3D? I do realize i would have to mod the control surfaces and whatnot. Is it built to heavy for 3D? Is a 150 just going to be to much weight?

twn

Deadeye, I just did a [link=http://www.rcuniverse.com/forum/m_9018718/tm.htm]build thread on the Goldberg Ultimate[/link], you probably already know of it.

Ultimates love power and there is no such thing as an overpowered ultimate! Heck For me my DL50 on my GP Ultimate 160 is not enough! LOL I want more! Go with the 150 if u already have it but the 180 is only like $20 more and is almost the same weight. I like my 120ax on my Goldberg, completely unlimited with a 16-8 but I’m considering a 15-8 for more rpm or burning 25% and using a 17-4W. I compared the tail feathers to my gp ultimate 160 (which is a 3d ulti) tail feathers and they have pretty much the same surface area, however the ailerons are not. To be the same u would need to increase them 30% on the cord to be of the same surface area. The thickness of the wings on the goldberg are the same as the gp 160 and the airfoil is very similar. With mine I enlarged my ailerons by 5/16 on the cord and about 1" on the length, REALLY makes a difference andany more might get hard to handle. It only needs about 10-15% defection for most maneuvers during normal sport flying and even that is touchy.

If you want this thing to be capable of 3d u will need to be VERY concerned about weight. This bird builds up heavy. It seams light as u are building but… I watched mine quite closely and still came out about 9.5 lbs. But mine tracks like an arrow and I LOVE it. Knife edge is a dream at this weight. Outside knife edge circles and outside knife edge figure eights should be awesome. For 3d you need to get it to about 8-8.5, this will mean u have to toss the solid ailerons and go with sheeted, lighten the airframe everywhere, but be mindful as the fuselage is constructed of really flimsy ply. Mine split on me in a few places without lightening. With a larger motor I don’t think u will get it under 8.5lbs. Too much strengthening is needed. Watch the tail feathers they could build up heavy, look for ways to strengthen the fin and stab but keep the weight down. Make that fin STRONG especially if u like insane blenders. I did with mine by using an additional piece of bass laminated inside the fin. With my stab I used carbon stips sandwiched on either side directly on the inner framework. It is ridiculously strong and light. I went with 625 rear mounted on my elevators, and will be switching to 985 coreless but the mini digitals are half the weight. This is a touchy area as I have friends who will only use strong normal sized metal gear servos and won't use the mini digitals as they have thin gears and they claim can break in this plane and I personally believe it as I used one on my somthin extra (moded with large tail feathers) on the elevators and I tore the servo out in one season but I put that plane through hell, crazy hard blenders, full speed into waterfalls etc…

I also glassed 1/2" from the front of the firewall to 1/2" around the sides of the firewall.

The wings build up heavy in the end make what ever mods u need to do to get rid of as much solid balsa as you can. This is only for 3d, if yer gona do sport flying or pattern the weight is better.

Toss the included firewall in the kit and go with 1/4 ply aircraft grade especially if you are going with engines as large as and larger than 120. This will add weight but the included firewall will not stand up to a large engine as well as induce more vibration from being weak. Use gorilla glue on the stringers on the front turtle deck, a lot of engine vibration is absorbed into this area and add an extra former to this area as the turtle deck tends to shrink a bit looking kinda wierd. If you can get it replace the kit aluminum cabanes with some thicker stuff. You will be grateful u did it. I know I will be sooner or later. Strengthen the interplane strut mounts with some 1/32 ply on both sides of the ribs.

Go with a fiberglass cowl and pants. With the firewall, cut it about 1/16 shorter in height than what the kit suggests and the cowl will line up better with the engine. My cowl sits to high by 1/16”. U could move the engine up but that takes the engine above the flight line. My 120ax needs about 3 to 3.5 degrees of right thrust maybe more, gotta play with it this spring. Right now it has 2.5 degrees and needs more. And maybe a little down, 0.5 degrees or so.

Do something with the stock gear, they are garbage. I wanted to try them, so I could say I did and I strengthen mine to the point that they would not fail and so I could easily add some after marker carbon ones with ease. The wire gear wiggle A LOT and with out modification WILL go through the lower wing very easily and/or seriously dent the LE of the lower wing. I will be getting some carbon gear for the spring.

Go with some light foam wheels.

I stress this, watch the weight. With ultimates they still fly good heavy but if you want to stall this thing out during 3d stuff it needs to be light. Something that could help would be to increase the wing cord by 10-15% that would add a lot of lift. You could also add 2” to each wing with very little grief.

In my opinion the plywood turtle deck is heavy. A 3/32 balsa one might be lighter.

Strengthen the lower wing mounts. I'm sure there is more in my thread. Fallingleaf did a great build thread too. I think it was called "Goldberg Ultimate Engine"

twn

My buddy Rory throws his around with a ys 140. That should be about the same weight as a 150. I honestly don't see why it can't be used for 3d. If you can achieve a decent weight and make those ailerons bigger u might be in buisness. I bet if u attack the solid balsa u could get the weight down. I watched mine but I could have gone much further in weight reduction...

Deadeye

Thanks guys! I will heed your advice.