Carl Goldberg Ultimate build (Full Version)

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

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



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

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[:D], i know i know, im a little embarressed



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

[8|]Beef up that landing gear block. It is a weak place on the fuse.



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

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.



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

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



nick1881 -> RE: Carl Goldberg Ultimate build (3/18/2008 8:58:27 PM)

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?



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

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.



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

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



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

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?[:D]



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

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



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

So dave do you think the ulti will match well with a 91fx?



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

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!



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

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!!!!!



daveopam -> RE: Carl Goldberg Ultimate build (3/19/2008 3:33:55 AM)

The last two I owned were both Super Tigre 90 powered. If you want to hover one it's not enough. Other than that it is perfect. I ran a MA or APC 14x6 prop and had no complaints. The knife edge was horizon to horizon at 10'. The flat spins were great the rolling circles were great. It really has no bad habits under power. Think hard about not doing the smoke. Or if you do put all the smoke stuff on a ply tray that can be pulled out with 4 screws. Once you fly it both ways you will leave the smoke out. at least IMHO.

David



daveopam -> RE: Carl Goldberg Ultimate build (3/19/2008 3:35:09 AM)

Nick, do you have a razor plane to bevel the control surfaces? It is a real time saver.

David



lrglnman -> RE: Carl Goldberg Ultimate build (3/19/2008 3:38:28 AM)

keep up the progress on this build. I will watch it closely. I love bipe builds.



nick1881 -> RE: Carl Goldberg Ultimate build (3/19/2008 3:41:05 AM)

Hey dave,
Yeah i was figuring that would be the general concensus about the smoke system. The flight performance you describe is awesome and i cannot wait to finish this plane!!!![:D] As far as the razor plane yes i have several actually. My old man made cabinets for 35 years so luckily i have access to alot of really nice stuff. The unfortunate thing is im at college like 3 hours away, but im able to go home about every other weekend so i will still have access to the shop.



nick1881 -> RE: Carl Goldberg Ultimate build (3/19/2008 3:42:23 AM)

IrgInman,
I will definately keep going strong and i will keep on putting up pictures too...You have any experience with bipes?



daveopam -> RE: Carl Goldberg Ultimate build (3/19/2008 3:53:45 AM)

I know the kit comes with a fixture to sand the bevel. But I found it a pain. I took the center marking tool that came with the kit and used it. Then took a pen and marked it. Then took a straight edge and pen and drew a line 1/8" back on both sides of the rudder or elev or what ever I was doing. Then took the razor plane and planed the bevel till it went to the center line and the line on each side. I have real problem with my sinuses and balsa dust. So I don't sand anymore then a have to.
One other thing I thought of. I lost my first Ult because the rudder post snapped in flight. I was doing a flat turn wide open at 15'. The rudder post snapped just above the fuse and the plane snapped inverted. I was to low to save it. I had used the round Du-Bro hinges with the steel pin. Great hinges but they did leave enough wood around them. I used CA hinges on the next one and flew it 8 years before it retired this year. I think I am the only one that lost one this way but thought it was worth mentioning.

David



daveopam -> RE: Carl Goldberg Ultimate build (3/19/2008 3:56:06 AM)

Here is my last one. It is navy blue on the bottom of the lower wing ,bottom of the fuse and bottom of the stab. VERY easy to see.

Notice I used the stock muffler. The $60 pitts I had bit the dust with the first Ult.

David



nick1881 -> RE: Carl Goldberg Ultimate build (3/19/2008 3:59:19 AM)

Man these planes look so nice and yours is no different. Have you had any problems with the wire landing gear? As far as the hinges go i already bought robart hinge points, but i suspected there might not have been enough wood there to keep things strong. So im really glad you mentioned that and i will go with the CA hinges like you were talking about.



daveopam -> RE: Carl Goldberg Ultimate build (3/19/2008 4:08:38 AM)

Yes the gear is the weak point. I have layed it back and put the wheels through the wing twice. The seocond time I landed in a 4" deep ditch. It broke the leading edge on both sides. That is also why it has no pants. They compound the problem. If every landing was under power the wire would be OK. I had to put it down a few times away from the runway. This will always lay the gear back. If you have no bipe time you will learn. If it dies land it where it's at. Do not try and glide back to the runway. The nice thing is the ULT will not snap. The wings will be level but it will come down at a 45 degree angle and pancake. This is why I tell people not to fly it on the recomended low rate of elev. You don't have enough to hold the nose up.
BTW if I forget to say later. I balance mine inverted and use my thumbs on the lower wing(which is on top when inverted), I go 3" back from the LE at the fuse. The Lomcevecs at this setting are great. I get three end over ends before it stops.

David



nick1881 -> RE: Carl Goldberg Ultimate build (3/19/2008 4:15:31 AM)

yes i have heard that deadsticks can be a ****. From what i have read you have to point it straight downand pull it out at the last second so you can try to keep the airspeed up. I will definately keep in mind what you said about the c.g. I cannot wait to try some lomecaveks with this thing. What kind of servos are you running in yours? Also what kind of reciever battery are you using? 4.8 or 6v? How many mah?



lrglnman -> RE: Carl Goldberg Ultimate build (3/19/2008 12:33:32 PM)

Nick I have the seagull arf 120 ultimate. but I have been eying the GP Skybolt very hard. I have been following the skybolt build closely in this forum. So all the info I can gather about bipes in general is going to help me in my future build. I have started leaning away from arfs. and building more. lets you customize the plane more. I am assuming this is the 120 size ultimate . I should work great with the Brielli 26 gas engine. I am thinking real hard about installing it in the Seagull. It will handle the weight no problem. THe Goldburg is suppose to be a bit lighter than the Seagull. Something to think about.



FlyingGreg -> RE: Carl Goldberg Ultimate build (3/19/2008 12:52:48 PM)

Nick--I saw above a discussion on hinges. When I bought mine already built, the builder had used CA hinges. I thought the ailerons were very sluggish first time i flew it and there was very little movement since the hinging was so "tight." I cut all four off and re-hinged with small Robart hinge points. I think I did the elevator as well, although I can't remember while I'm typing this. Freed up the movement of the ailerons remarkably. I also purchased the TNT landing gear which is an aluminum stock gear rather than the wire gear. Eventually I will buy a fiberglass specialties cowl to replace the stock ABS, but for now it's holding up. A note on the cowl--I have learned that if you add a layer of heavy glass cloth inside the cowl and apply PVC pipe cement over the top, with the little dauber that comes in the can, the glass sort of "melts" into the ABS. It adds a little weight, but not much, and your cowl will last forever. Be sure to do it in an area that ventilates well as the PVC pipe cement is very "fummie." Try it on a scrap piece of ABS. You can also do the wheel pants but have to do them before gluing the halves together. The OS 91 you have for it will be great. You might want to get a Pitts muffler just to keep from having to cut up the cowl so much.

Good luck.

Greg



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