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Carl Goldberg Ultimate build - 3/18/2008 6:03:49 AM   
nick1881


 

Posts: 47
Joined: 2/23/2008
From: greencastle, PA, USA
Status: offline 		I recently bought a goldberg ultomate after having read great things about the way they perfom. i plan on keeping a build thread as i may have some questions later on or some people might have questions for me. I plan on using an O.S. 91 fx for power (with a slimline pitts muffler) and using my trusty old futaba 6ax computer radio. I was hoping to use a smoke system as well but ill have to see how light i can build it. For the cowl and wheel pants im going with fiberglass specialties, as i have heard the plastic stuff in the kit is not very durable. Im also going to make my own landing gear out of 1/8" aircraft grade aluminum. The rib that the struts attach to is going to get doubled with a piece of 1/32" aluminum. I want to go with dual elevator and aileron servos and a sullivan heavy duty pull pull setup. another thing i was thinking about was an ohio rc tail wheel setup.


So any other suggestions or comments anybody has i would like to hear them- good or bad
thanks
nick
       Post #: 1

RE: Carl Goldberg Ultimate build - 3/18/2008 6:09:09 AM   
nick1881


 

Posts: 47
Joined: 2/23/2008
From: greencastle, PA, USA
Status: offline 		I built the horizontal stab tonight and it went together real well. Everything fit nicely and i think it came out pretty good. i took pictures which i will post tommorrow and i will also try to finish the elevators, vertical stab. and the rudder.

p.s. could some one tell me how to upload pictures into this thread , i know i know, im a little embarressed

(in reply to nick1881)
       Post #: 2

RE: Carl Goldberg Ultimate build - 3/18/2008 1:07:15 PM   
flyreel


 

Posts: 28
Joined: 11/20/2002
From: berryville, VA, USA
Status: offline 		Beef up that landing gear block. It is a weak place on the fuse.

(in reply to nick1881)
       Post #: 3

RE: Carl Goldberg Ultimate build - 3/18/2008 3:38:57 PM   
FlyingGreg



Posts: 551
Joined: 1/21/2002
From: West Chester, OH, USA
Status: offline 		Hi Nick-- I have one of these. I didn't build it though, I bought it from a freind. I put pull/pull and installed Hitec 225 minis in tail for each elevator half. I had a Saito 180 on it to start with but that is way too much motor. I now have an OS 91FS and it flies it just fine. Can't do 3D but everything else is great. it wil KE for ever w/o coupling.

BTW, to post pictures, you need to use the Post Reply button. You can't post pictures using this Fast Reply space.

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RE: Carl Goldberg Ultimate build - 3/18/2008 3:51:13 PM   
daveopam



Posts: 4212
Joined: 10/10/2002
From: ELK CITY, OK, USA
Status: offline 		The Alum doubler is a waste on the ribs. It is not needed. If your going to use two elev servos then try a couple of minis in the tail. You could glue in a couple of the punch outs under the stab and mount them there. The twin aile servos is how most guys build them. I use ply doors in place of the balsa doors with the slots in them. Then mount the servos to the doors on their side. The wing is really thin on these. Even with this set up the servo will push the covering out slightly on the bottom of the wing. Not a big deal and you will be the only one to notice. Using the gear you are talking about is a great idea. The front fuse double would need to be modified a little. I would make the opening about 2" in place of the 1"one that is there. This will give your gear block plenty of strength. You could even run a 1/4" dowel through the block into the slot made for the stock gear.

One other thing on the twin elev servo set up. With the radio you have you will need a servo reverser or a reverse Y harness to mount the servo the way I suggested. You could get around this by mounting them inboard. I just don't think mounting them inboard is going to give you any advantage over the stock one servo set up. I have used the stock set up with a Dave Brown pushrod for years. It will keep your throws in the sport range. But if you are not going to 3D it then it's fine.

Good luck on the build. This will be one of your favorite planes. David

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(in reply to flyreel)
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RE: Carl Goldberg Ultimate build - 3/18/2008 8:58:27 PM   
nick1881


 

Posts: 47
Joined: 2/23/2008
From: greencastle, PA, USA
Status: offline 		Hey guys thanks for the advice so far, i like the idea of minis in the tail for the elevator halves and i will definately beef up the fuse where the gear attaches. I built one elevator inbetween classes today and i will build the other tonight along with the rudder and vertical stab. In the mean time here are some pictures of the horizontal stab and the one elevator. Anybody have any thoughts on the added weight of a smoke system?

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< Message edited by nick1881 -- 3/18/2008 10:07:59 PM >

(in reply to daveopam)
       Post #: 6

RE: Carl Goldberg Ultimate build - 3/18/2008 10:56:19 PM   
alfredbmor



Posts: 911
Joined: 6/1/2005
From: El Paso, TX, USA
Status: offline
quote:

ORIGINAL: daveopam

The Alum doubler is a waste on the ribs. It is not needed. If your going to use two elev servos then try a couple of minis in the tail. You could glue in a couple of the punch outs under the stab and mount them there. The twin aile servos is how most guys build them. I use ply doors in place of the balsa doors with the slots in them. Then mount the servos to the doors on their side. The wing is really thin on these. Even with this set up the servo will push the covering out slightly on the bottom of the wing. Not a big deal and you will be the only one to notice. Using the gear you are talking about is a great idea. The front fuse double would need to be modified a little. I would make the opening about 2" in place of the 1"one that is there. This will give your gear block plenty of strength. You could even run a 1/4" dowel through the block into the slot made for the stock gear.

One other thing on the twin elev servo set up. With the radio you have you will need a servo reverser or a reverse Y harness to mount the servo the way I suggested. You could get around this by mounting them inboard. I just don't think mounting them inboard is going to give you any advantage over the stock one servo set up. I have used the stock set up with a Dave Brown pushrod for years. It will keep your throws in the sport range. But if you are not going to 3D it then it's fine.

Good luck on the build. This will be one of your favorite planes. David

I have built this great bipe and I consider it as one of my all time favorites, I made some of the mods posted by David and added a smoke pump, you can find some ideas here:
http://www.rcuniverse.com/forum/m_4913575/anchors_4913575/mpage_1/key_ultimate/anchor/tm.htm#4913575
At first I had some problems with parts that did not come in the box but the Carl Goldberg company assistance was ok so I could keep building my bipe with out many problems.
I heard that I should make an extra doubler for the landing to reinforce the landing gear area and I did it. No problems till now.
In my appreciation I consider a 90 two stroker in the lower side for the optimum performance of this bipe. I have a 120 Magnum four stroke here and have been thinking for a while to change for other engine lighter and more powerful but I have not find any good option here. I have been thinking that maybe a Saito 125 could be a good choice. But you have to invest some more bucks.
Either way you decide to take, for sure you will end with a great flying biplane. I wish you good luck and a lot of fun on your build thread.
Alfredo.


< Message edited by alfredbmor -- 3/19/2008 3:08:02 AM >

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RE: Carl Goldberg Ultimate build - 3/18/2008 11:10:44 PM   
nick1881


 

Posts: 47
Joined: 2/23/2008
From: greencastle, PA, USA
Status: offline 		hey thanks alot for the luck. As far as the motor goes i know everyone has been putting the big four strokes in them but that is a problem for me. The problem is i dont have 350 bucks to shell out . So im going to have to settle for the o.s. 91fx. I do have a question out there tough and maybe someone out there can answer it. The .91 fx is rated at 2.8 hp and weighs around 25oz with the muffler. An O.S. 1.20 four stroke is rated at 1.9 hp and weighs 33oz. So its almost a half a pound heavier and makes almost one less horsepower? Whats the deal here, shouldnt the 2 stroke give the plan a much better power to weight ratio?


any help out there

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RE: Carl Goldberg Ultimate build - 3/18/2008 11:41:52 PM   
nick1881


 

Posts: 47
Joined: 2/23/2008
From: greencastle, PA, USA
Status: offline 		Ok its 6:30 here on the east coast and i just got done with the vertical stab. So here are the pictures. I have some work to do but i said i would have the rudder done also so ill be back at it in a few hours and then ill get a picture of the rudder up here too. Man the more i build this thing the more i realize its alot bigger than i had anticipated. Build a plane and listening to hendrix...does it get any better?

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RE: Carl Goldberg Ultimate build - 3/18/2008 11:44:22 PM   
daveopam



Posts: 4212
Joined: 10/10/2002
From: ELK CITY, OK, USA
Status: offline 		First the advertised power is not worth looking at. Most two strokes are over inflated. Some even give the power at 16,000RPM when the engine runs best at 10,000RPM. Also a 4C is all about torque. The 91 will swing a 12x6 at 11,000 or so. The 1.20 will swing a 15x8 at 9,500 or so. Which one has more power? It's a toss up sometimes depending on brand.

David

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RE: Carl Goldberg Ultimate build - 3/19/2008 12:16:10 AM   
nick1881


 

Posts: 47
Joined: 2/23/2008
From: greencastle, PA, USA
Status: offline 		So dave do you think the ulti will match well with a 91fx?

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RE: Carl Goldberg Ultimate build - 3/19/2008 1:11:08 AM   
David Jackson


 

Posts: 222
Joined: 4/15/2002
From: Nashville, TN, USA
Status: offline 		I built the Goldberg Ultimate when it was released about 15 years ago. I used an OS 91 four stroke for power and it flew very well and was very predictable with no nasty tendencies. You will enjoy the the Ultimate with the powerplant you have selected. Have fun!

(in reply to nick1881)
       Post #: 12

RE: Carl Goldberg Ultimate build - 3/19/2008 3:25:23 AM   
nick1881


 

Posts: 47
Joined: 2/23/2008
From: greencastle, PA, USA
Status: offline 		alright so here is the rudder almost finished, besides some rounding of the perimeter pieces. I had some trouble with the widths of the different pieces matching. But it wasnt too bad just a little extra sanding. You can definately tell this is going to be a high performance airplane, this rudder is HUGE!!!!!

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< Message edited by nick1881 -- 3/19/2008 3:47:38 AM >

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