I'm just beginning construction of my Great Planes 33% Giant Extra. If anyone has any comments, suggestions, tips, notes of caution or advice regarding this project - please feel free to let me know.

Chuck

I buillt and am flying one of these now.
It came out tail heavy with the ZDZ80rv, I have had to add close to a pound of lead to the nose. My plane is about 23lbs with the lead.

it might help to invest in a digital scale so you can choose the lighter sheeting for the stab/rudder.

There are a couple reports of people who had wing failure, you should brace up the main ribs which hold the wing tube especially where there are those big lightening holes.

The shear web system is pretty good, don't try to force the spars to fit extremely closely
if they don't fit flush top/bottom with the shear webs, if you force them it will cause warping, better to fill the gap later with soda/thick CA. This is especially important on the leading and trailing edge shear webs.

The canopy mounting method is not optimal, it is better to build the entire top hatch removable similar to the Cardens/Aeroworks. Ron Eisner posted pictures a while back on how to do this. Also build the cowl with a cowl ring so that it mounts from bolts from inside the fuse instead of all those bolts going around the edge of the cowl. This is much better.

The wing tubes are cardboard, not phenolic, check that they are circular and fit the aluminum tube properly, it would help to harden them from the outside afterwards with thin CA before the soften up and cause excess play later. Do this before covering the plane.
You can put a stick through the wing tubes just past where they want you to put the wing bolt, this way the aluminum tube will stop there and you can put a hook in the root rib and use rubber bands to hold the wings together instead of the bolt though the wing tube method.

The fuse side sheeting is a real PIA.
Otherwise the plane is nice flying and a bargain at the price compared to other 33% options.

If you want pics I'll try to organize.

L

I don't known if you purchased an engine for the plane, if not I used a FPE 5.8 and it balanced right on. Vertical is unlimited and lands vary nice. I would recommend phenolic wing tubes; you can get them from TNT Products. When it comes time to glue in the wing tube screw blocks there will be a gap between it and the tube. I fulled it with epoxy it makes a stronger set up.Then when you tap the wing tubes it will not only thread the tube it will put threads in the epoxy so they won't tend to come loose. The wing tube acts as the shear web, but there is none beyond where they end. I put vertical grain webs in the next five rubs. Not much weight for the peace of mind. As for lennyk's recommend cowl mounting idea, that is what I did, makes for a much nicer looking set up. Good flying plane I'm sure you will like it!

Ronk ... I have a 3W-100 that I want to use. Its the older version which is a bit heavier. I will probably have to move my batteries way back to balance but thats cool.

Lennyk ... I would be interested in more info about how you mounted the cowl. It must look clean not seeing any screws around the outside of the cowl. On wing attachement, I thought about installing some 1/4-20 or larger nylon bolts from inside the root rib, instead of the alignment dowels. Then just put some wing nuts w/keepers on them from inside the fuse.

What servos did you guys use and how many servos on each aileron? Im using JR 8411's for ailerons (2 each) and elevators. Using one HS 805 for the rudder w/DHS pull pull.

Thanks for the tips,

Chuck

Here is my version of the GP Extra 330

The 3w100 should be just right! What I did for the cowl mounting is cut a 1/8 ply solid ring that matched the supplied pieces(I think there are six) then used # 10 socket heads with blind nuts in the fire wall. As for the servos I used Hitec (4)5625 digitals in the wing, too much surface for one ea. The wing mounting idea sounds good but there is a advantage of using GP's mounting. You can make spacers for each wing that will let you change the span from 100.5 to 103.5 and have two mounting threads in the alum. tube depending on what type of flying your going to do. When there outward you gain about 45 sq inch in wing area with no adverse affect(I checked with GP before hand that said no problem). I'll post some pics tonight.

Chuck, I have attached a few pics, blue circles on the cowl are where there is a blind nut behind which accepts the bolt from behind the first former, I have also circled the bolts for you to see. I use a 2-56 ball driver from inside. There are also a couple 1/8 dowels used to help align the cowl when holding it whilst bolting.

I made a little booboo in that I made a former over the top, this was not necessary and could have been done a different way but I did it from scratch as a first try. You can look at other people's Carden's build pics and see how the hatch could be done without that former running over the top, the hatch will run straight to the cowl.

L

Ronk,

What did you use for spacers ?
did you make them in the shape of the complete root rib ?

Yes, if you have not made the wings use the root ribs to make four copies. Here are some pics of my 330L it was dark out(went flying) I'll try and get better ones

I did not notice who the reply was to. Your plane is together,no problem same idea but you will need to trace them. Then make blocks to space them(where the dowels are) so the trailing edge of the wing is 1/4" inside the fuselage. Then sheet the top and bottom for strength. You can put them in or take them out as you like. I use them for slow speed maneuvers and you can land the plane at slower speeds.

ronk1 ... do you have a pic of those wing spacers? That sounds like a good idea.

Thanks everyone for the pics ... they help give me ideas about mine.

Should I just use thin CA over the cardboard wing tube to harden it up or would getting a new one from TNT be a better idea? I would like to use what came with the kit but ... I do want it to last too.

So far I have completed the left stab and elevator. Just seeing that one piece finished gets me all amped to get it done!

Chuck ;-)

Chuck,

I just started mine and I finished the stab. It goes together real quick and I made sure the stab was built as light as possible without sacrificing strength. Are you going to double bevel the control surfaces or not? I am going with 2 of the mods I have seen on RCU they include the hatch and cowl ideas already mentioned here.

Bill

To give you another idea, here is how my engine is mounted. I didn't use the standoffs.

I built my canopy a little different to give better support for the plastic.

I'm in the process of adding a phenolic bearing to the wing socket on each side of the fuselage. The cardboard tube is a little sloppy for me.

Tom

Very nice installation, good work.

Bill,
Yes I am going to use double beveling. Im not sure why though. I just know that most big planes I see at the flying field have em that way so there must be a good reason. If nothing else it will be easier to seal the hinge lines! Plus ... on the plans I think the rudder and fin are double beveled so I want the elevators and stab to match.

I already screwed up my left stab. I didnt notice the fact that the aft spar was balsa. I used the basswood on one side before I realized the plan called for balsa. So ... I will make the other side to match. Seems no matter how I try ... my planes always end up on the heavy side. Oh well.

Tom ... thats a very clean engine install. Seems everyone is goin with the ZDZs.

Im still in a quandry about the wing phenolic tube. Not sure I should use it or replace it. Its too late for changing the one in the stab.

Chuck

Chuck,
The wing tube inside the wing seems OK. Just the part that goes through the fuselage seems to have some slop. I'm adding a phenolic disk to the fuselage side to tighten it up.

I love showing off my pictures...

Tom

The problem with cardboard tubes are they shrink or swell with the humidity. If you do use them do not use thin CA, use med. the thin can soak through making it so the alum. tube does not fit.

Tom! HA! Is that the nutritional contents of Frosted Flakes on the rudder I see? Thats hilarious Great lookin plane too. Wheres "Tony the Pilot"? Did you double bevel your elevators, ailerons?

Chuck

Im building the fuse now. The holes in the aft laser cut sections where the horizontal stab tube sockets slide through are too big. The fit of the tube socket (cardboard tube) is very sloppy. Is there a reason for this?

Chuck

I finished mine a couple of weeks ago. It's turned cold now here in Michigan, and looks like the maiden flights won't be until Spring... Details: Brison 4.8 twin, Hitec digital servos (5645 + 5925's), Airtronics Stylus PCM, ElectroDynamics Pow'R Bus Pro, 4 cell Nicad on ignition, 4 cell NiMH on receiver/throttle/choke, 5 cell HiMH on balance, Ultracote and PPG paint. Total weight 24 lbs.

Regarding the wrong size holes for the stab tube, I called GP about this when I received my kit. They sent me updated parts that were better. No, I don't think there's a reason or purpose, just a mistake.

Mine is pretty much stock. I made two changes. I added Dave Brown CF on the wing spars (on the outside, between the spar and the sheeting). This is left over from my glider days. Adds a tremendous amount of strength to the wings. I don't fly too aggressively, but I do think this will reduce any chance of the wings folding like some have. I also totally changed the canopy construction. I built a frame from pretty hard balsa, and left it open. This was lighter than the stock method, gave me some "meat" to put screws in around the sides for the canopy, a place to mount a block to hold in place with screws from the outside, plus I think it looks pretty cool. Some of the higher end giant scales do something similar to this, at least that's what I saw at Toledo. Here's a couple of pictures. The first two were before painting, the last one after.

Looks good and at 24 Lbs it should fly great. 24 Lbs with a twin is light for this plane. Most end up 25-26(my 330L is 25) ready to fly! I'm building a Ohio RC 33% Ultimate now. It took a long time to find one but its the only one I know of in this size. Its not the easiest kit to build but I have all winter.

Well thats just dandy. I already have my fuse built. Are the updated parts something you add to the previous structure or do the new parts replace the original parts?

And what is this about wings coming apart??? I havent heard anything about that. And of course my wings are already done. What can I do to strengthen them now? They arent covered yet. I did notice that the wing tube doesnt go all the way into wing sockets. Would a longer wing tube help keep the wing from failing? Geez ... now Im getting worried about flying this thing. Ive never built a kit of this size before so I just built it according to plan. I did seem like a wierd wing design though. Having that wing tube built so close to top of the wing seems like it could pull right out. But ... like I said ... I already built them according to the plans. Hope Im not doomed.

Chuck

I have been flying mine for 3 years now, nothing ever broke on it yet. Go to idle coming down from a loop

I agree with Roger. Don't worry about it. There are a number of them flying, and most report no issue. The situations I've heard about were either from being very overpowered or high G manuevers at high speed. The instructions from GP are very specific about engine size, weight and speed limitations. I think if these are honored, you will be fine, as others have been. I put in the CF because it adds almost not weight, and gives an extra margin of safety. But I could just as easily have left it out and I wouldn't have worried about it.

The pieces in question that GP provided replaced the original laser cut ply pieces on the fuse side around the stab tube. If you already have it built, it shouldn't be a problem to filet the stab tube with epoxy/milled glass, or even just another piece added on the inside.

I agree the wing construction is a little different, but it's actually just a much larger version of what they use on several other of their models. In GP's tech support FAQ, they specifically mention that the wing tube doesn't extend all the way into the socket in order to reduce stress being in one place. It's done that way on purpose.

Thanks for the info guys. I feel better now. I will call GP today and see if they can send me the parts. I could probably just glue the portion with the proper hole diameter to the inside surface of my aft fuse sides and filet in around the tube like you said.

I have a 3w 100 for power. That should be ok right?

Chuck