So I got lucky and picked up a brand new CG kit. It's all framed up and ready for sanding. The fiberglass Cowl and Wheel Pants are almost ready for paint but, there's a few things I don't like. This will probably be the best aircraft that I will ever own and I want to set it up right. Anyone have some setup ideas or what to do's for me?
I'm thinking of a big 2 stroke up front. I can get a good deal on a new Webra 120 ???? How many are running the stock Elevator linkage??? Any tips and ideas will be very much appreciated
Thanks

I fly a Goldberg Ultimate with a Webra 120 in the nose. First of all, put the servos in the tail. I did not, and have the batt in the canopy and 3 ounces of lead in the tail. It's on the Re-Do list for this winter. I'm thinking about using only 2 servos in the tail however, to avoid any possibility of differential throw. I'll probably use a Sig offset control horn to do so. The 120 with a 16x6 APC is a blast! Everything happens at 1/2 throttle or less. I can't imagine more fun with a plane. Put a piece or two of tri stock in the tank compartment as the Webra is a shaker. Also, look at where the cabane attaches to the fuselage. The kit puts 4-40 bolts into light ply there. You may want to add some hard birch ply plates there and use slightly longer bolts. Buy a Bisson Muffler and cut 1/2 of an inch off of the exhaust pipes, you won't regret it! I gained about 300 RPM on top, and lots of throttle response. It's a bit louder, but nobody has mentioned it at my field. I can tell, but I don't think anybody else noticed.
Good luck, and look foreward to it!

Similar experience to TailTwister, except I have a TT 120 in mine.

I'm currently in the process of recovering mine (over 10 years old) and moving the servos back.

I added a little carbon fibre to the mount points of the cabane. I'm going to reinforce the elevator couterbalances as they keep breaking loose when I enter the 'blender'.

Thanks guys,
Good to hear about the 120's, I was hoping to hear the Servo's were mounted at the tail. Tis going to be a great year 2003

TailTwister, I'm running a 16-8 on my Webra 1.20 in a CG Sukhoi. I'm only turning about 8k with 5% nitro. The engine seems to like this set-up just fine and gets excellent fuel economy. What rpm do you get with the 16-6?

16x6 APC on 10% Cool Power gets 9500 running cool. I can push a tad over 9700 if I feel the need. That's getting hot, and really isn't worth it though.

No doubt I would get more pulling power with the 16-6, but isn't that prop getting pretty loud at 9500?

We don't have a db meter, but My fun flys with a Rossi 45s are noticably louder overall. (12.25x3.75 @14,000 RPM with a tuned exhaust) On my bipe I think the prop is quieter than the exhaust, but the funny thing to me is the Ultracote can be heard over both. Between the wing and tail where the "BLUEHAWK" logo is resonates at full throttle. It can be heard over both the prop and exhaust. I have heat gunned it a few times, but it still resonates. It just changes frequency for a few flights. I bought two 18x5 Zingers and will crop one to 17x5 (for experimentation sake)and try and lose speed (and noise) but gain a bit of pull. I've heard that they are not particularly efficient props, but I'll give'em a try. Most reading I've done says that a prop gets "unreasonably loud" at 0.7 Mach. That would actually be more like 11,000 RPM.

Yea, I get a lot of covering noise too. My Sukhoi has large areas of unsupported covering on the fuse. If 11k is the "loud limit" for a 16 inch prop, I think I'll give the 16-6 a try.

21 st Century fabric is much quieter.

Best suggestion is to lower the cabane height by 1" and shorted the interplane struts by 1" as well. This will help reduce the coupling issues inherent to all biplanes.

-Doug

Ditto on the servos in the tail - that's how mine is. Easiest way to do this is that when you start work on the fuz sides, do not punch out all of the cut-outs in the lite-ply - leave the rear ones in for servo mounting, and perhaps one forward one for switch and charge-jack mounts - run a little CA in the cut-line, then add some hardwood behind that for the servo-screws to bite on.

Mine is the old CG kit (the one that came with the horrible ABS parts rather than a fibrglass cowl), so I don't know what the current cowls are like. If you find that the cowl is too tight for your engine, then you might want to buy a new cowl from Fibreglass Specialties. They offer[ed?] two types - one of which is deeper in the chin in order to cater to larger engines without needing too much hacking. On my ST90 with large pitts-style muffler, only the top 1/16" of the cylinder head protrudes - everythnig else is totally enclosed by the deep-chin cowl.

As for resonance of the airframe - I found that the worst effect of this was that the pushrods between upper and lower ailerons set up a standing wave at certain RPM, thereby effectively shortening the rod and pulling the upper ailerons down even though the lower ones are still level. To fix this I used fibreglass pushrods.

Some people ***** about the wire gear and insist on putting aluminum plate gear on, but a better suggestion is just learn to land... if you put plate gear on and land hard, you do a lot more damage than if you bent some music wire. FWIW, mine has the original wire gear in it after about 8 years worth of use.

One thing that I found does wear out though, is the upper wing mount. The holes that the retaining pin pushes through tend to gradually open up. I've replaced the entire mount twice so far, but that's many hundreds of flights, with some pretty vicious stresses on it.

Regs,
Gordon

The Ultimate has very little coupling anyway. I wouldn't worry about the cabane or struts. It' is famous for it's knife edge performance.