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Goldberg Extra 300

Old 01-07-2006, 03:13 PM
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Default RE: Goldberg Extra 300

Has anyone replaced the plastic bottom of the canopy with balsa etc? This setup seems kinda of fiddly to get all together.
Old 03-27-2006, 02:40 PM
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Default RE: Goldberg Extra 300

My Goldberg Extra is now 11 years old, and is still the best flying model I own. During this time most everything has remained original with the exception of the following mods.

The wire L/ gear was changed to alum, and a fiberglass cowl fitted. The ST 90 engine was replaced with a Zenoah G23 gas engine lightened and converted to elect. ignition by Ralph Cunningham.

The Rx battery pack has been relocated to the rear for balance, and at a flying weight of 10 lbs. the Extra has retained all the great flying manners it had at 9 lbs.

I read earlier in this topic where someone made a full balsa canopy deck, so check back and see. So far mine has given me no problems after umpteen flights, but I did do some balsa/silicone reinforcing underside my ABS canopy tray.

Karol
Old 07-30-2006, 07:09 AM
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Default RE: Goldberg Extra 300

Just starting on a Goldberg Extra 300. I willl be using an OS two stroke 90 on this plane. Up to now all my experience has been with 61 powered planes and smaller, including a Great Planes 46 Chapman Cap,all of which have had CA hinges. I have the CA process down well and have never had a problem , knock wood. I would like to use CA on the 300 but have heard mixed reviews on planes with this level of power. Has anybody used CA on this plane? Any thoughts? Thank from Cape Cod.
Old 07-30-2006, 08:50 AM
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Default RE: Goldberg Extra 300

I used epoxy in the firewall, wing centre joint, wing saddle and landing gear areas and CA extensively everywhere for lightness. So far after 11 plus years of service its structural integrity is still is as good as new. I think the key is to always use a good brand of glue.

Though holding some back pressue during take off works, one mod I did as I fly from a grass field was to fit a 5/16" thick hardwood wedge under the alum l/gear I used which rotated the mains about 1" forward curing any tendency to nose over.

It is presently powered by a elect ign G23 and is the nicest flying model of that size I have flown. With Goldberg's very indepth construction illustrations and instructions, I'm sure you will enjoy both building and flying this model.

Karol
Old 07-30-2006, 02:40 PM
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Default RE: Goldberg Extra 300

Thanks, but did you also use CA hinges for the control surfaces?
Old 07-31-2006, 11:41 AM
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Default RE: Goldberg Extra 300


ORIGINAL: frdeluca1

Thanks, but did you also use CA hinges for the control surfaces?
Yes I did, and though they have worked perfectly, if I had known that I would have ended up with a gasser up front, I would have used plastic hinges throughout.

Based on the size engine you have selected for your model, make sure you use the one servo per aileron as recommended, and I hope that you will keep us posted on your build progress.

Karol
Old 07-31-2006, 11:50 AM
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Default RE: Goldberg Extra 300


Thanks for the input. I have already assembled the fin and rudder and horizontal stabilizer and elevators. I am at the point to cut the slots for the hinges and round the edges. I normally do all my building in the winter so I doubt I will do much more now as this so flying season here on Cape Cod. I certainly will post my progress though.

Thanks again for your advice.
Old 08-05-2006, 04:28 PM
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Default RE: Goldberg Extra 300

I have finished thevtail feathers and about ready to start on the wing. The instructions call for building both halves of the wing together requiring a 70 inch building board. I have always built each wing half separately and then joined them thus requiring a more manageable sized building board. I understand the belts and suspenders approach used here with the fixtures to assure perfect alignment, but it seems like an over kill. Did you folks all build the wing as instructed or did some of you deviate and build each panel separately?
Old 08-05-2006, 05:04 PM
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Default RE: Goldberg Extra 300

The instructions that came with my 1995 kit indicated that the wing should be built in two seperate panels and then joined, which is what I did. Maybe the wing design or the instruction manual has been revised, but building the wing in two halves and then joining them proved to be ideal for me.

Karol
Old 08-06-2006, 12:29 AM
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Default RE: Goldberg Extra 300

What does everyone think about strapping an OS 1.20AX into this plane? Just trying to figure out what engine I'd like to power it with....

Shane
Old 08-06-2006, 06:11 AM
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Default RE: Goldberg Extra 300

From all I've read and heard guys use anything from 90 - 150 size glow engines. Remember the model was designed to be flown on a 60 size engine, so anything in that range will work, it just depends on how crazy you want to be.

For me, and as you can see from the posts a 90 size engine works just fine, but I wanted to experience gas so I shoe horned the G23 into mine.

Karol
Old 08-06-2006, 10:08 AM
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Default RE: Goldberg Extra 300

Well I figure its not much heavier than a 90, it bolts into the 91FX mounting holes, and it should give me the extra umph for extended vertical stuff. I guess I'll give it a try.

Shane
Old 08-06-2006, 05:01 PM
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Default RE: Goldberg Extra 300

Go for it and tell us how it went.....remember the bottom line is to have the most fun.

Karol
Old 09-19-2006, 01:52 AM
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Default RE: Goldberg Extra 300

I have this plane powered with an OS 90 2 stroke. Lots of power but not unlimited vertical. It has alum landing gear, and beefed up bottom to support the gear. Used pull pull rudder and 2 servos for ailerons and 2 on elevators. Moved the gear forward quite a bit to increase stability taking off grass. Now no problem. Weight close to 9.5 lbs. The extra power of the OS120AX would be great. Balance should not be a problem as the 120 is not much heavier than the 90.

Buce
Old 09-19-2006, 05:47 AM
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Default RE: Goldberg Extra 300

I am in the process of building this kit which I am also going to power with an OS 90 two stroke.

Did you use the stock cowling? How about fuel tank size? Could you indicate the servos you selected and on what voltage? Any pictures of the landing gear support and location? Also any description of how you mounted and rigged the dual elevator servos would be appreciated. Did you have to add any weight to balance?

Thanks in advance,

Frank
Old 09-19-2006, 05:55 AM
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Default RE: Goldberg Extra 300

Skyriter,
I've had 2 Goldberg extra's both using the O.S. 1.08, with a 16-6 APC, very good engine for the plane which will hover at about 7/8th throttle. You should have no problem building 2 separate wing halves and joining them together. As stated earlier if your flying off a grass field reinforce the landing gear area with aircraft ply and move the gear as far forward as you can to prevent nosing over. Buy a good fiberglass cowl too. Great flying plane.
Old 09-19-2006, 06:03 AM
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Default RE: Goldberg Extra 300

fredeluca1,
Here's the set-up on my Goldberg Suhkoi, which is the same as the Extra, dual elevators with pull-pull on the rudder. support backets not installed yet on carbon rods.
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Old 09-19-2006, 06:14 AM
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Default RE: Goldberg Extra 300

Gunfighter II:

Thanks for the pictures. They will be a great help! Any suggestions on what servos to use ond on what voltage?

Thanks again,

Frank
Old 09-19-2006, 06:32 AM
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Default RE: Goldberg Extra 300

Frank,
I'm using Futaba 9001's on elevator and a 3010 on rudder for the Sukhoi. I spent a little more money on the Extra and used Futaba 9202's on elevator and 9303 on rudder. 6 volt on both. With the exact set-up pictured I needed 1/4 ounce on tail to balance, but with your 91 2 stroke you will be just the opposite. I can't remember if the Extra came with a wire gear, if it did, buy a aluminum gear for it. The fuel tank is a problem as there's not much room so you have to stick with the stock tank unless you want to do a dual tank set-up with a header tank, I get about 10 minutes on my 12 ounce tank with the 1.08, but I'm rarely at full throttle. Any servo of at least 50 oz in for the elevator if using 2, and 100 oz in for the rudder will work fine. The fiberglass cowl is a must, the one supplied will break and fall off. Go to Stan's or Fiberglass specialties, I found a good one from RC City in Colorado at a hobby store.
Old 09-19-2006, 06:50 AM
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Default RE: Goldberg Extra 300

Thanks again, this is all a great help.

Frank
Old 09-19-2006, 08:22 AM
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Default RE: Goldberg Extra 300

Two more questions ( I promise): How about servos for the ailerons? Will 50 oz- in do it or would you suggest more such as the 9001. Also any pictures of how you beefed up the landing gaer support for the aluminum gear would really be appreciated.

Thanks again
Old 09-20-2006, 06:21 AM
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Default RE: Goldberg Extra 300

Frank,
The 9001 should be just fine, I use the same servo for the aileron as the elevator. Another good choice would be the 3152 digital.
Old 09-20-2006, 06:41 AM
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Default RE: Goldberg Extra 300

Frank,
This one's pretty crude looking, this plane has about 400 flights on it, but I just used a 1 inch piece of 1/4 inch aircraft ply spanning the width of the fuse, in the picture I've done it twice as the first placemant was to far back, the gear is sticking about halfway over the area where the fuse angles up to the firewall, 2000 Mah Nimh batt is all the way in the rear of the plane. The 1.08 is a little heavy. I used a bigger piece for the Sukhoi and some basswood supports on the side, but I can't get a picture as it's closed up. Feel free to PM me with any questions you have regarding your build.
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Old 09-20-2006, 06:45 AM
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Default RE: Goldberg Extra 300

So far 50 oz aileron servos have worked well for me. For beefing up the landing gear area to accept the alum gear I have no photos.

I used a 3" wide piece of 3/16" aircraft grade ply the full width of the fuse from the front edge of the gear area, which was sandwiched on the inside with 4 pieces of 1" sq 1/8" lite ply for the l/gear bolts blind nuts. Both inside corners of the fuse/ply joint was strengthened with std 3/4" trianglar stock while a similar sized shaped fillet was used between the tank bulkhead and the l/gear ply.

Karol
Old 09-21-2006, 01:52 AM
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Default RE: Goldberg Extra 300

Did not use the stock cowl - Ordered a fiberglass cowl for it which was much easier to fit etc. The AL landing gear is the heavy version. Tilted the gear foreward, so that the center of the wheel was at the leading edge or slightly in front. Used a haigh style tail wheel with spring connections to a rod through the Rudder. The tank I used was a 14 OZ tank - GR236 available from Hobby Lobby. This is a short tank and fits into the tank location with no problems. The tank mount was not glued in, but fastened with a couple of screws. This allows for tank removal if required. The servos that were used were JR DS 811 - 2 on elevators, 2 on ailerons. Used Htec 5625 for Rudder - pull-pull. Throttle was JR 537. Used 1400 Nicad 4.8 volt. An extra Elevator servo hole was added to the servo mounting plate, and both Elevator servos mounted there with golden rod connections back to the Elevator. Don't have any pictures of the gear mount. If I can get some in the new days - will post. Used Bisson muffler on the OS91 2 stroke, and had to plug one of the pipes to get enough back pressure to get the engine to run correctly.

Bruce

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