Now if hobbico would just read your thread we could all have one

I thought that 2.7 deg was quite a lot of dihedral for an extra.

What is the dihedral on the Goldberg kit?

Assembled the centre section, quite simple to do.

On presentation of the centre section to the wing, the middle mark of the centre section was off the spar joint line by about 2mm (just over 1/16"). I checked the wing with a tape measure and confirmed that the spar joint was the actual centre - which it was.

What was causing the discrepancy was the half rib on the wing being at an angle relative to the centre section half rib. I cut loose the wing half rib from the dihedral brace and positioned the centre section lined up with the spar joint and epoxied all in place. Looks good.

Next top sheeting.

I thought I've read the dihedral guage was set at 3 degrees. I haven't checked that though- I'll have to get back to that.

Technically there is no dihedral. The wing builds as shown in the first drawing. Is the GP Extra set up like pick 2? I had an Edge that was set up this way and thought the Extra wing was set up the same way. I was definately wrong with my Extra!

You build VERY clean! It is fun to compare the two builds side to side- and at the same pace!

Thank you for sharing your build.

Brian

Wing profile is more like photo 2, although the top spar has a slight incline to the wing tips.

I found the wing jigs to be a real pain, cos every time the wing shifted slightly the jigs would fall over. Ended up tacking them to the wing tips with thin CA. worked great agter that.

Sanded down the wing and started attaching the top sheeting.

Top sheeting finished, glue drying.

Andrew,

As they say - steady she goes. Looking Good by the way. You are getting close to finishing the easy stuff. For me - covering and component installation is always the most time consuming part.[]

While you are at the stage of the wing and have mentioned dihedral-I have a question for those that have built and are flying this plane. How is the rudder to roll coupling????

I will be seriously considering the removal of some, if not all, of the dihedral built into this wing. But I would really like to here from some that are flying this kit. Thanks in advance.

The dihedral on the upper surface is really small. If you didn't know it was there you would have to look twice to check it.

However I would be interested if anyone has taken out the dihedral and what difference it would make. Too late for this build, maybe the next one.

Some photos of the wing. complete except for the wing tips and centre rib caps. - Alot of sanding on the leading edge. Debated using the razor plane but was concerned about making one cut too many. All in all took about 40min to sand both sides.

Added the root and tip caps to the wings - photo 1 & 2
Laid out the Aileron for the right wing. Can't find the section of plan for the LH aileron LOL, I will need to print another copy on Monday.
Finished aileron photo 4 without the end caps. i have left these off so I can make minor adjustments to length against the actual wing openings on assembly.

Started to lay out the fuselage and glued on the side doublers with aliphatic resin - Photo 5 & 6

Firewall laminated with epoxy and clamped - photo 7

Front former (former 6) glued in and squared up. - Photo 8

Next to glue the side walls to the formers. Instructions say to wet the outside with water and glue to the formers using thin CA and accelerator. I have read on RCU that this step was quite tricky and that soaking the side walls first and then bending around a suitable tin (saucepan) made it easier.

Well I soaked the side walls in cold water for about 30min, don't think it made much difference to how easily they bent, certainly could not form easily to a 7 inch diameter tin.

Presented the sidewalls to the formers and doing a little at a time (using thin CA and accelerator just like the instructions said) was able to shape the sides to the formers. I went over all the joints with thick CA afterwards.

Fairly happy with the result, although the top of the sidewalla betwen former 6 & 7 has barreled a bit but I am sure that that will be addressed when the rest of the fuselage is built around it to hold it in shape.

Calling that a day for today

I have added the fuselage formers and the fuselage bottom but have a concern. I ave been careful to make sure everything fits into the interlocking tabs neatly and as per the sequence in the instructions.

When I added the fuselage bottom after the three rear of cockpit formers, (8, 9 & 10) Former 10 was wider than the fuselage bottom by about 0.5mm per side. This results in a non linear fuselage side. I checked the plan and the side is non linear, i.e. not a straight line from TE of wing to rudder post. The perceived deviation is uniform on either side. So I thought does it matter? and glued in the fuselage bottom. A couple of days on I have added the wing bolt block and this too did not fit the fuselage nicely and I had to sand the fuselage to get a good fit. This was a result of the position of the fuselage doubler on the side wall as the only reference in the poitioning of this item is to align with former 7. It is only when you get several steps farther that you realise that the position could have been better to accomodate the wing block.

Each of these in isolation is not a problem but both together made me think that either the piecces could fit better or a dry fit of the whole fuselage before gluing anything is necessagry to get the pieces sanded correctly. This is academic as it is not possible to dry assemble the fuselage. Sanding of the wing block mounting was not a problem, but to rectify the fuselage sides I have to do either one of two things;

1. Sand the fuselage sides to be parallel to the fuselage bottom. This will reduce the thickness of the ply sides around former 10 by about 0.5mm (1/32") each.
2. Leave as is and fill the gap between the fuselage sides and the fusleage bottom with micro balloons and sand to suit

Either is easy to do but just trying to guage what other kit builders would do.

A picture speaks a thousand words:

Photo 1 the fuse side shown overlapping the fuselage bottom at former 10

Photo 2 - Perfect fit a former 9

Andrew

It ain't (a little Texas draw for ya) going to be worth much. But, here is what I would do on the edges. I would either take a piece of small square balsa and fill the edge and then resand to taste or use some lightweight "spackling" to fill and then sand. Epoxy and microballons would work as well.

Peronally I like rounding all those sharp corners anyway. The thin plywood may cause a problem for me on this one.

Good Luck

Andrew

It's been 6 days since anything new.

Any progress? Hoping you haven't hit a wall like me.

Brian

Thanks Rick, in hindsight it is probably a really minor issue, but I do like to get thinks fitting neatly. I will "soften" the edge before covering and see how it looks then either add spackle or microballoons to fill any bigish dents.

In general i have found the fuselage and belly pan parts to be ill fitting. In fact the belly pan stringers (part 18 I think) while they matched up in length were 1/16" different in width. Lots of sanding of parts, especially around the firewall and belly pan areas.

I will post progress photos's later, but I have completed the firewall box and landing gear rails and added some reinforcing tri-stock behind the firewall.

When doing the fuselage build you need to keep aware of several steps in advance and trial fit before gluing. One aspect where I would differ from the instructions is to glue in the ply landing gear rails before fitting the firewall box bottom. This would allow greater ease of rail fitting which when the box is complete requires a degree in gyneocology.

Progress over the last few days:

Photo 1 - completed wing belly pan
Photo 2 - Front fuselage assembly with landing gear rails fitted
Photo 3 - Internal firewall reinforcement, vertical
Photo 4 - Internal firewall reinforcement , horizontal
Photo 5 & 6 External firewall reinforcement

Bolted the wing to the fuselage and leveled it up then checked the incidence.

left Hand Root 0deg
Left Hand Tip 0deg
Right Hand Root 0 deg
Right Hand tip -1/2 deg

The RH tip does not concern me at this stage as very little pressure is required to rotate it to 0, so I should be able to correct this after covering without too much trouble.

I am at the point now where I need to install the control surface control rods. I want to use a Pull Pull for the rudder and to this end I have purchased the Du Bro 4/40 set.

I have never installed a pull-pull system before and wondering if I should wait untill the fin and rudder are installed before fitting the cables? Should I run the cables in the tubes provided or not?

If the cables do not run in the tubes how do you do the fuselage exit?

Andrew,

Looking good........

I have run pull/pull rudder set-ups with and without the plastic tubes. I have even run them with just a short piece of tubing at the exit. I make my decision on the plastic tube based on how difficult it will be to run the "cables" through the finished fuse. I also consider if there is a chance for the cable to be rubbing on a bulkhead or something. If that chance exist then I use the plastic tubing.

My preference is certainly to pre fit everything at the stage you are. In other words cut the exit slots if I am not using tubing or run the tubing now if it is to be used. I would pre fit the control horns on the rudder and do a mock up with rudder and vertical stabilizer in place to mark cable exits. Typically I will not fit the cable (cut it to length) until after all assembly and covering is finished.

Andrew

You should keep finishing completely separate from building and control installation. Assemble the airframe and put in the controls before installing a square inch of covering. At some point your plane should be ready to fly except for the missing finish. This way you can verify that everything goes together correctly, check all alignments and confirm that the controls work properly. Dissassembling the model for finishing and then reassembling might seem like too much extra work, but it isn't.

Pushrods in their housings have friction, while cables move with little resistance. Pull pull cable systems neutralize more accurately and give faster response than a pushrod system. So in order to take full advantage of the pull pull system it is important that the cables not touch anything on their way to the rudder control horns. Unless the plane is designed around the pull pull system guessing where the cables exit the fuselage usually involves a bit of trial and error, thus the importance of doing this before covering. By the way, on smaller planes it might be necessary to cross the cables before they exit the fuselage.

I'll snap a few photos and send them in a later post. One is the set up on a 80" span Ultra Hots scratch built and the other is a Pacific Aeromodels .60 size Edge.

Al Zalner

More progress:

Slow week, but I managed to install the front turtle deck formers, stringers and sheeting.

Also trial fitted the HS base - was way off so made a new one tracing the outline of the fuselage onto one of the cut outs of the fuselage - check alignment of new fit and happy with result.

Next step to fit the HS to the fuselage, got to wait for a break in familly responsibility for a couple of hours to do this.

Hey Guys,
I bought my kit yesterday at the lcal hobby store. I was looking something to put my saito 120 on, and thought this would be a nice fit. I am not a 3d flyer so weight is not a big factor to me at this time. I have a smoke pump that is also looking a home and this might be it. We will see as the build goes on, and how I feel too. I got my horz.stab. built last night and the vert. stab and rudder skins. the wood for glueing these was great. I did not have to do anything to them to get a perfect fit! I shortened the stab by half and inch and will build the elevators half an inch bigger. I also will be adding balance tabs to the elevators.

There are some great planes (pardon the pun) on here to try and match. I'll be watching learning, and asking questions later.
Alan

bg:

When you say the elevator will be 1/2" bigger, do you mean just making up for the 1/2" you removed from the horizontal stab? Or does the total fin length increase by 1/2"?

I ask because this is the mod that many have mentioned but I am never sure about the "add" meaning....

Correct I moved the hinge line forward by half an inch and will make up the difference with the elevators. I read about someone doing this on another thread here on RCU. There is a link to it on the first page of this thread.
Alan

I know the link...Adrian posted it.

I was just not sure if the "added 1/2" was really just making up for the amount removed or if an ADDITIONAL 1/2" on top of that was called for....i.e. 1" total or 1/2" bigger than stock.

If I read you correct, overall size stays the same? For the inside edge (beside the elevator) how do you set the angle? Start or end in same place?

Can you post with drawing behind it when you are done?

I will be glad to post some pix, but I did not make any drawings for the horz. stab. I used the thats about right theory.
Alan