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Goldberg Extra 300

Old 09-18-2009, 05:33 PM
  #476  
Gray Beard
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Default RE: Goldberg Extra 300


ORIGINAL: frdeluca1

I few replies ago I indicated I couldn't do flat spins with my 91FX powered GB 300. I wonder if my elevator throws were enough. On high rates I measured 3/4'' up and down. Just finshed *****g them out to 1 1/4'' up and down. Anybody that does do flat spins with this plane have measurements for their elevators?

PS: Don't know if anybody esles has had problems with tank preasure with this engine side mounted,but I solved my stalling problem a couple of years ago by pinching shut one of the exhaust tubes on my muffler.
Mine does the flat spin very well and my elevator is set for HR at 10 degrees and my low LR is at 8 degrees. My CG is right at neutral, when I go inverted I have to add no down at all. CG on this plane may be the key to knife edge and flat spins?? Most all my other planes like just a taste of nose heavy CG but my CG Extras seemed to fly best where I have this one set now.
Old 09-21-2009, 11:06 AM
  #477  
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Default RE: Goldberg Extra 300

Bipes was the twisted wing covered if not you really won't be able to use the heat gun to your advantage.
If the wing is covered there shouldn't be a issue taking out that small amout of a twist with the heat gun, I place the wing on the plane with it proped up to 0 degrees on the stab or next to the fuse on the wing and go from there, depending on the twist a extra person may be needed to hold the tail down. Remember this you have to let the wing cool down before you let go of it or the twist-warp will come right back, also remove any wrinkles in the covering you have put in by twisting on both the top and bottom, hold it for say 30 secs to cool then recheck. Also you need to go past the point of 0 say 2 degrees if possible the oppisite way.
Granted it takes a little practice to get the hang of it, my biggest worry is burning a hole thru the covering, or if its a multi covering job pulling the seams apart.

I'm with Grey Beard I have taken out more than a degree of warp in a wing and also added more than that by accident just covering the wing.
If push comes to shove and the wing is not covered cut the sheer webs loose wet the wing and twist the wing past straight and add new webs to the back of the spars.
Old 09-22-2009, 04:19 AM
  #478  
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Default RE: Goldberg Extra 300

Hi Guys

This is my first post and Ihave solely joined so that Imay comment on this thread, reason being is that Ihave recently purchased a CG Extra 300 kit. This is a great thread and I am very interested to see comments and pics on all builds but especially Brian's, as Ifind myself to be equally "anal" (English expression.....means I suffer from the same OCD as Brian!) and Iwont settle for any imperfections in my build, especially when it comes to the wings.

So, Ijust wanted to present myself, say hi and quitely sit in the corner and listen to all of your guys knowledge and experience.

How is your build coming along Brian?

Kind regards

Carlos.......from the UK.
Old 09-22-2009, 07:14 AM
  #479  
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Default RE: Goldberg Extra 300

Welcome aboard. I am not that active but still able to welcome you. Take it you are from the uk as I am.
Am sure you will share some of your knowledge- so fill your boots here as we say in the uk.
Did you happen to get your Kit through ebay just a couple of days ago. I was watching it untill the end when I forgot about it.
Old 09-22-2009, 10:37 AM
  #480  
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Default RE: Goldberg Extra 300

ACAMEX-

Welcome to this thread. I invite you to share any opinions, ideas or techniques you wish to share.

I started my 2nd wing this past weekend. The wood is more consistant, and easier to work with.

My 1st recommendation is to cut a full TE jig that runs from the center section, or rib 2 out to the tip, rib 10. There are only 3 jig tabs in the kit. This does not support the TE in the sheeting process properly.

I also drew a centerline on all my ribs, drew out the length of the ribs from the plans, and the correct loacation of the spar. I found these thing to be off- significantly.

Once the ribs were tacked in, I measured the centerline of the ribs at the LE and the TE relative to the flat building surface. I found that a few ribs were off by 1/16 inch at most. That translates into only a 1/32 shift up or down at the TE ot LE. I can live with this.

Here are some pictures of my progress:







Brian
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Old 09-22-2009, 11:36 AM
  #481  
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Default RE: Goldberg Extra 300

Dobra and Brian, thank you for you kind welcome.

Dobra

It would be a pleasure to share what knowledge I have....though most of my knowledge seems to be in strange things from a piggy back glider mechanisms, firing missles from planes to fitting FPV cams on them.

I purchased my kit from the BMFA website, annoyingly there are a few bits missing that Iwill either have to fabricate or source from my crashed Funtana :S

Brian

The wing looks great! serioulsy good job

"........... I found these thing to be off- significantly." < me too!

Iwill take some pics of mine and put them up on here.

Regards

Carlos
Old 09-22-2009, 11:40 AM
  #482  
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Default RE: Goldberg Extra 300

Carlos-

Let me know what you are missing. I may be able to get a template to you (it would be my 1st overseas mailing though). I'm drawing templates as I go. Other people have asked for them as well, and even though I haven't said much about it lately, I am getting them drawn.

Brian
Old 09-22-2009, 12:01 PM
  #483  
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Default RE: Goldberg Extra 300

I am watching this thread as I am a fan of the Goldberg Extra... curious about your tracing the parts. Have you been keeping a copy of all the ribs and fuse parts? I would like to downsize everything and build a smaller version that could handle an OS90 or OS70 4-stroker. One of my "want-to-do" projects but I did not keep track of the parts as I built mine and now it is no longer with me. It had an OS1.08 2 stoke on it.
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Old 09-22-2009, 12:31 PM
  #484  
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Default RE: Goldberg Extra 300

Carlos, welcome aboard. Brian isn't being anal about this build, he is going to compete with it so it has to be as dead on as he can make it for IMAC flying. I just didn't want you to think we were thinking of him that way. Mine measured out perfect and is so easy to fly it makes me look good. We were just trying to help him from having to build another wing if it could be helped. For sport flying that little twist would mean nothing but for IMAC you don't want to be fighting any building flaws.
As of now I make templates of any and all kits I come across because kits are being dropped from the manufactures line up every day. It's just a good idea to be doing it. I have a few planes now that I regret not making templates for and have been kicking myself in the hinder.
Old 09-22-2009, 02:00 PM
  #485  
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Default RE: Goldberg Extra 300

Grey Beard

Thank you for the welcome, it is truly great to have a warm welcome, it can certainly be intimidating to enter a forum full of experts etc, so to receive a such a great welcome speaks wonders for the type of people that are here.

I totally understood the reason for Brian's precision and why you guys were trying to help him, Ihave also been there when that sinking feeling hits you when you finally decide "I'm going to have to build another wing!!"

Time for my firstquestion, and this question is simply down tome notwanting to get things wrong... and probably not being able to follow instructions correctly.

I am starting to build the wings, (at this point you will need to refer to the instruction manual)...on section 8 it refers to the "set back gauge" when fitting the top spar, I assume that this piece has a certain angle to it, but is this part of the kit? If so, could you guys tell me on what number sheet its on? If not then am I safe in assuming a normal 90 degree tool would suffice? As I mentioned before my kit turned up with parts missing, so im not sure if this is one of the missing parts.

If I am not making sense then please say and ill try and explain better.

Thanks guys
<o></o>

Old 09-22-2009, 02:06 PM
  #486  
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Default RE: Goldberg Extra 300

Brian

Thanks for the offer of sending the templates, it was very kind of you. Maybe when I have more of an idea of what is missing then I may take you up on that

Perhaps this is something that we could talk about in a different thread or at a later date. I am also in the process of making my own cnc router, so if you were able to create the templates in a .cad format then I could potentially cut them at home and send them to any person in the UK that needed any part.

The cnc router is a way off being complete though, so this is just food for thought.

C
Old 09-22-2009, 02:45 PM
  #487  
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Default RE: Goldberg Extra 300

Carlos,
I can only tell you it's made of light ply, and it is not at 90 degrees, although it is very close to 90. It is used so that the inside of the top spar is located off center, so that when the wing halves are put into the cradles when they are joined it will account for the very little amount of dihedral that will be built in.
If you cannot locate it, I personally wouldn't sweat it. I would put the spar in at a 90, and when you place the wings in the cradles, you will just have to sand away or cut a very small amount of top spar so that they butt up against each other.

Al
Old 09-22-2009, 03:46 PM
  #488  
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Default RE: Goldberg Extra 300

Thanks Al

Im currently searching through all the pieces that I have, if I cant find it ill do what you recommended    Thanks again
Old 09-22-2009, 07:47 PM
  #489  
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Default RE: Goldberg Extra 300

bigal126 - Carlos,
I can only tell you it's made of light ply, and it is not at 90 degrees, although it is very close to 90. It is used so that the inside of the top spar is located off center, so that when the wing halves are put into the cradles when they are joined it will account for the very little amount of dihedral that will be built in.
If you cannot locate it, I personally wouldn't sweat it. I would put the spar in at a 90, and when you place the wings in the cradles, you will just have to sand away or cut a very small amount of top spar so that they butt up against each other.
bigal126 is right on here. I found that using the set back gauge did not set it up properly anyhow. I had to do more sanding on the spars oncce I set the wing in the cradle.

Carlos- Make sure to inspect the wingtip cradles for the spar marks, and pin them on top of the plans at R10 lining the marks with the spar.

Brian
Old 09-22-2009, 08:10 PM
  #490  
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Default RE: Goldberg Extra 300

FREAK OUT!!!!!!!!! When Carlos asked about that wood gauge I went out to the shop to look at my instructions. I couldn't find the envelope with my plans and instructions!!! I tore the shop apart looking then on the second go around I found them in the bathroom under the sink. I couldn't find the gauge showing on the parts sheet but I remember it as being hard wood. I decided to look on my blue prints and I discovered I was missing the sheet with the wing build on it!!! I built the last plane as a gift for a friend and sent the instructions home with him and he mailed them back to me a while back, sure hope he missed a sheet when he assembled this package!!! Sure glad Carlos aske the question or I would have never noticed the missing sheet until it was build time.
Gene
Old 09-22-2009, 10:54 PM
  #491  
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Default RE: Goldberg Extra 300

As you can see, I don't build by the book.
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Old 09-22-2009, 10:56 PM
  #492  
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Default RE: Goldberg Extra 300

more pics
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Old 09-22-2009, 10:58 PM
  #493  
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Default RE: Goldberg Extra 300

I can almost smell the nitro burning. The weekend after next I think!
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Old 09-22-2009, 11:09 PM
  #494  
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Default RE: Goldberg Extra 300

two more. now to get some sleep!
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Old 09-23-2009, 02:13 AM
  #495  
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Default RE: Goldberg Extra 300

VERY NICE!!!![sm=thumbup.gif]
Old 09-23-2009, 03:58 AM
  #496  
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Default RE: Goldberg Extra 300

Bigal

Nice build, your almost there! You will have to give us an update as to how the maiden goes and how she flies !

I like the job you did on the skinning, looks well done from what I could see in the pics.


Just one question though, what do you have holding the 2 control rods together for the elevator? Is that going to enough to hold them together?

I decided to go for the 1 x servo on the outside rear of the fuse and join the 2 elevator halves together with a piece of thick wire, I will put a pic up to show what I mean better.

C
Old 09-23-2009, 07:42 AM
  #497  
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Default RE: Goldberg Extra 300

Here are my mods. 1.Added 1-1/4" chord to bottom of rudder. 2.Glued tri stock to LE of all control surfaces. I can't seem to sand to a nice bevel. This worked out great. Adds 1/4" chord to ailerons, and 3/8" to rudder and elevator. 3. Cut lightening holes in aileons and fixed TE. 4. Moved fuel tand to over CG. Perry pump is supposed to draw the fuel. Hope this works! Couldn't see shoehorning the tank in up front. Graupner 14.5 oz tank. 5. Moved elevator and rudder servos back one bay. Trick here is to make sure the servos line up for the pull / pull. I got it dead on!. 6. I noticed that the wing was a heavy 1 degree negative incidence in relationship to the stab with the wing laying on top of the fuse as the plan shows. Therefore, I cut the fuse so that the TE of the wing drops down and it lays flush instead of laying on top of the fuse. The incidence is now zero and it looks much more clean and neat IMO. 7. Nyrod for the throttle and golden rods for the elevators. The part holding the elevator pushrods together behind the servo is designed for the wire rope industry and has a 480 lbs rating. I think it will suffice! 8. The LG is homemade. 1/8" aluminum that when the plane is level, the axle holes are 1" behind the LE. 9. Aileron servos hatches are homemade. Servo is secured to the hatch, not to the wing. Very neat setup. 9. All dubro control surface horns. 10. The canopy is screwed into the holder, not glued. Painted the inside of the canopy not the outside.
Old 09-23-2009, 08:38 AM
  #498  
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Default RE: Goldberg Extra 300

I did the same thing to my servos, moved them back to help offset the engine weight ,but I did use 2 servos for the elevators, I also opted to use the servo plate to hold the servo and not the wing.Thats sort of a chessy way they do it in the manual.

I now have reports on both the GB extra 300's I made this year,and both are very favorable. The guys that got them are more than pleased with the way they fly and handle. They damn well better be, that's way to much work to give away and won't happen again *LOL*
No seriously I got to see the maiden of one of them last weekend ,after I spent 3 hrs going over it to get things set up correct and the CG on spot, the plane flew as if it had flown 5 mins before couple of clicks of up and it was flying on its own.
I still think the YS 120 engine was a nice combo for that plane.
Old 09-23-2009, 09:22 AM
  #499  
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Default RE: Goldberg Extra 300

That's great to hear. It's a testament to your building skills as well as the design of the plane. The YS 120 is too much engine for me. I might have my hands full with the OS 91 2 stroke. Looks like the build came out fairly light. I'm expecting the AUW to be under 9 lbs. I am a new pilot who lost his trainer (sig midstar) in a mid air.[>:] I plan on going up on the buddy box for this plane with my experienced friend at the club. This plane built extremely straight and I am confident it too will fly well. My midstar which was my first ever build, only needed a litte down trim, and I didn't even know what an incidence meter was then. Once I got a hold of an incidence meter, I can see that this plane is aligned very well. The only anomoly is the 1/2 degree in the wing that I will probably take a shot at fixing with the twist and heat the covering method when I get the chance and a helper.
Old 09-23-2009, 10:15 AM
  #500  
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Default RE: Goldberg Extra 300

Bigal, you've done a beautiful job! Congratulations on building and owning a special airplane, next is the fun and thrill of flying that special airplane. It's named the "Extra" for a reason!

Not being a downer, you may have to add some lead to the nose. I like your servo locations with the tank at CG, but with the OS 91 it may be a little tail heavy. If you do end up adding some lead, don't despair. Mine is a pound and a half heavier than yours without any lead and it flies as close to perfect as perfect gets.

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