I may be slow, but I am making (some) progress!

No one is in any hurry, it's fun watching your build. Did you get the sheeting figured out?? I would have told you how I do it but I don't use the wood glue for sheeting, I use CA and when I come into the house even my wife knows what part of the build I have been doing. I too started using more and more wood glue these days.
Gene

I did get the sheeting figured out. I'm pretty happy with the results too!

Just like with any new technique, it will take a few tries to master it everytime, but I think it works really well. It really looks like I caked the glue on the bottom of the skin. I didn't.

For anyone interrested in how I sheeted the wing using only Titebond 2, without the headache of pins and weights, here is the link where people helped me learn how to do it.

[link]http://www.rcuniverse.com/forum/m_9010746/tm.htm[/link]

There is more than one way to use wood glue. Some people like using both CA and wood glue. There are good instructions for that as well. I was even honored that Bax jumped in to help. Anybody could find at least one technique they would like in this thread. It's still growing too. Good info.

Brian

When I was the owner of the GB 300 Extra, I ordered a tank from Hobby-Lobby. Model GR236. This was a 14 oz short fueld tank that seemed like it was designed for the GB. I flew with a OS 91 and it gave me 10 minute flights with lots of fuel to spare. I think when I got the tank, it actually came from Germany.

Bruce

I have a 14oz and I have got 17mins with about 1/7 left over. I do 13min flights and that is enough for me.

I'm a bit concerned with my ST 90. It is an amazing engine that runs GREAT! ...only...

Point the engine down just slightly and it quits. It is adjusted properly.

I've visited a couple threads, and it seems I'm not the only one with this problem. Other engines suffer with this as well. I don't know if the amount of vacuum produced is the issue or not. Most engines run fine for the few seconds they are in a nose down attitude. They are running on what's left of the fuel in the lines. Mine doesn't.

So I was thinking.... here it comes!!!!

The two tank idea would solve this problem. So long as the front tank is full of fuel (It should be as long as the rear tank has some fuel.) the engine ought not never starve for gas.

The other idea is run long brass tubes out the front of the tank, bend them over the top or sides of the tank towards the rear of the airplane. At the back of the tank bend them forward again and attatch the fuel line there. It should make the fuel lines considerably longer and hold more fuel. Hopefully it would last through the normal pattern downlines in the sportsman sequence.

Any comments?

Brian

Hi Brian

Just read through all 17 pages, whew, didn't get to build tonight coz of all the reading. I just sheeted my wing (GP extra) using aliphatic resin and pins - no CA. I have previously tried the iron on method using white glue but was not happy with the result but like most things there is a technique to be learnt - maybe I will try again on the other wing panel.

Any pointers?

Yes. When you are ready to apply the heat (everything is lined up to end where it needs to end), start at the high poing of the wing (the spar) and work your way forward to the LE and aft to the TE of the wing.

This is where I blew it today. I found that trying to start at the LE to keep the seam tight and work my way aft to the TE actually pulled the sheeting away from the LE about 1/16th inch. I don't think I let the glue set up long enough. Mine is still salvagable. I still think I have enough glue surface to be safe. Chalk this up to the learning curve I guess.

My preferance when sheeting is definately in line with Sig's Hog Bipe. Their method is seamless. It may take a bit more effort, but it would be stronger, light, and possible straighter then the current method is- IMO.

Brian

p.s. I also think that the glue needs the 30 minutes to set up on both the bones and the sheeting. It sticks better- just like contact cement.
I have also found that after the glue has completely set up, you can still hit it with the iron and tack it down if you find an area you didn't get right.

Also, it helps to have the sheeting edge-glued and prepped before you install, rather than glue it on the wing one piece at a time.
I may document how I do that. There is no secret, but it is just magical how well alaphatic resins (wood glues) work for this!

How about this for templates? I placed the cut out ribs onto a photocopier (lucky to have an office at home) . End up with a 1:1 print, I could even scan at 1:1 and email.

OK these are the GP ribs not the Goldberg but easier to make than card templates. paste onto balsa sheet and sand down to the edge.

I set up my boat tanks like this. A 1 or 2 ounce tank that feeds the motor, and pulls supply from the main tank. Give it a try..

Is muffler pressure alone enough for this set up?

Doesn't get any better then that!! I once did that for a fellow here on RCU for the Midwest Hots fuse formers. I didn't want to remove them from the sheet so I used a pen to highlight the outside of the die cutting. Worked out very well.

I always thought the copier put the copies out just a bit smaller than the originals. How well do the parts line up?

It is difficult to compare exactly now as all the ribs are glued into the wing, but a couple of key measurements indicate that the copy is ever so slightly larger (chord length of 225mm vs. 224mm measured on the wing). And that could be paper stretch or tired eyes after a hard day[&o]

I will check again when I do the formers for the Fuz.

Pictures with questions!

Is the top of the wing supoosed to stay flat, or does it taper down like the bottom tapers up? It would be like having dihedral and anhedral.

Before I glue the two panels together, I thought I'd make sure.

Brian

You're fine.

From root ribs out to wing tips it's basically flat, but a level placed flat on one side of the wing (I assume it's flat on yours but not showing in your pictures) does result in exactly what your pictures show.

Is the 1st pic or the 2nd correct?

#2 is correct.

WHEW!!!!!

I was starting to think I might have messed up.

Brian

Well, I was hoping to post pictures of my wing joined. But...

Turns out nobody carries 20-30 minute epoxy anymore. I have to wait until the LHS opens up tomorrow and hope they carry it. I hate waiting.

The only thing I could find is 5 minute epoxy. I have that. I know it sets up faster, which is no big deal, but shouldn't it be good enough for the wing joiner?

Brian

Personally, I wouldn't use 5 minute to join the wings. I've been using 15 minute mid cure for everything I've epoxied in the past three years. I think 15 minutes is enough time to seep into both surfaces to get a good bond. Around here the 15 minute is sold in most hobby stores under different brand names. Clear plastic round bottles with an orange top on one bottle and a black top on the other.

Other then the work time, and 5 min. is fast, one of the thoughts behind the longer setting epoxies is that it absorbs into the wood for a better bond the longer it takes to cure. It's one of those deep thinking things and you have to make your own call on it??
I have used 5, 15, 30, 45 and 60 minute epoxy and never noticed it soaking into the wood. I once used a finishing epoxy on a wing and it worked, that has about a 15 hour set up time and had me worried for a long time, it seemed a little brittle to me but the wing stuck together until I did a bad thing, even then the center section held.

I agree completely. I try not to write a novel on every post, and you've done an excellent job of distilling what's up. It is a sort of deep thinking thing, this seeping/absorption occurs on nearly a molecular level.

If anyone has scientific specs on glue/mastic absorption of different woods it would be interesting to see.

I do remember at least one instance of poorer results with 5 minute, which is why I avoid it - but that could have been surface prep on an old firewall that would have presented issues anyway.

I'll wait to use the proper tools.

Thanks

I wanted to add this link. It is a testiment to using the proper tools and techniques.
(RCKen, I hope this is okay.)

[link]http://www.rcuniverse.com/forum/m_9036411/tm.htm[/link]

OK, trick time for gluing with epoxy. When I have to mate two surfaces with epoxy I always drill a big bunch of small holes through the two surfaces so when the parts are clamped or weighted the epoxy flows through the holes to the other surface. Really adds a better grip. While I'm tricking I may as well tell it again, fire walls always get some holes drilled through the fuse into the fire wall sides then I use cut down tooth picks and epoxy them in. I have had some hard crashes that have busted up the fuse but the fire walls were still hangine onto what was left of the fuse sides. I have a dental hand piece on my bench with a lot of dental burrs of all sizes and found one that is a perfect fit for tooth picks.