I'll be starting a CG Ultimate kit any day now and look forward to any tips on building this plane. Mine is not laser cut but looks pretty good. I'll keep an eye on the fuse saddle "weakness" as I build. I understand that the ply wing ribs that the N struts attach need to be strenghtened but not sure how. As I've been reading through the instruction booklet it seems that these wings don't have any dihedral. Am I reading this right? Thinking of putting a Super Tigre 75 2 st in it. Good motor for this plane?. I know a 90 or 1.20 4 stroke would be great but up here in Canada the price opn these is pretty high. Besides, I'm a long way from full out airbatics, just enjoy the basics and am happy with a good flying, somewhat reliable, easy to handle plane.

I'm finishing my Ultimate this winter too. I bought mine framed but,uncovered. Just making a few mods including mounting the Servos in the Tail. Don't punch out all the ply on the back of the Fuse, instead re-enforce it and mount the Servo's in the Tail.
(This was a tip brought to my attention here at RCU)
Also the cabanes need to be re-enforced. Apparently and not restricted to the maneuver they call the blender. It is a weak spot, I read better support is needed in the Fuse to support the upper wing. Not sure if I'm going to add anything to the metal supports or just re-enforce there mounting. I too read about the saddle, I'll have to address that myself.

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I think the Super Tigre .75 would be ok. I was thinking about the Webra 1.20 for mine but I hear that makes for a hot plane. I have a new .76 that I might just end up putting in her.
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I've got zero degrees Dihedral in my wings. I hear incidence is crucial with these planes. I also hear they glide like a Concrete Block and like to snap on take off !!!!!
We'll see
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There's a few discussions on them in the 3D/Pattern Forum

Check out the Higley's book, "Bipes", for many good tips on building the Ultimate.

Dave Segal

build the plane by the prints and you'll have a great flying plane,plane needs a little power to land,does not fall like a brick, take offs are like any plane and better than most bipes.never seen one snap on take off yet.If you need to add 2x4 and steel beams,then 350 chevy engine to get if off ground ,then you probably will not enjoy the plane,if a person has to crash proof a plane,go back to a trainer and get some more stick time,don,t mean to pi-- anyone off but rumors can ruin a plane,if a person hasn't done,don't say it,may be missleading,OK?

HHHOOOOOWWWWAAAAAAA!!!







Al Pacino
Scent of a woman

These are all tips that I have read here at RCU. Don't know where you get 2x4's and 350's from, but whatever pal!!!!

The CG ultimate flies great when set up properly. Don't move the CG too far back, and use the recommended control throws for low rate if you are going to 3-D. The cabaines are a weak spot if you push it hard, but don't get silly with reinforcement, it's important to keep it light. It will snap if you try to horse it off the ground, so don't and you wont have a problem. It will also stall rather aggressively, this can be made more gentle if you want by adding 1-degree pos incidence to the TOP WING ONLY. All things considered its a very nice plane to fly. :^)

2x4s??? Chevy 350 engine??? Rumors???

Well, let's see. First, I'm one of the guys who advised against removing the fuse lightening knockouts. That advice was given after seeing two of these models break one or both fuselage sides right above the lower wing saddle during hard landings. I guess you're an expert pilot and never make a less-than-perfect landing.

Second, I don't deal in rumors without specifically stating such. Below is the CG Ultimate I built 10 years ago. Sorry for the poor reproduction, but I don't have a scanner and was in a hurry. The model had an OS 120 Surpass turning a Graupner 14x7 3-blader, which was plenty of power for normal aerobatics. The model was not over-weight, and it did indeed fall like a brick dead stick. As long as you kept it diving, you were okay; but better be in a position to set it down NOW when you flared.

The fuselage is weakened by removing those cut-outs. The airplane has a lot of drag and does not glide well. Those are facts, not rumors.

Steve

Steve, I agree with most of what you said. I did not remove the cut-outs on mine and covered one side with light weight glass. I also added pieces of 1/8-inch balsa and a couple of triangle stock gussets linking the cabiane support to the LG plate that extend about 1 1/2 inches over the wing saddle doublers. Have not had any problems. As far as power off glide, it's not great, but I think pretty typical of any draggy biplane airframe its size and weight. And as far as bad landings I'm the freakin' king, I've bounced so hard it's gone back to pattern altitude!
How does the 3 blade work, the 15/8 on mine mows the lawn.

I still don't like the fuse cut-out advise. I think there are better ways, like using a trippler that ties into the forward wing mount and the adjacent former.

I am gluing the ply rib cut-outs back in and reinforcing both sides of the cabane mount tabs with 1/32 birch ply. Also extending the shear web to this rib. This adds virtually no weight but adds considerable strength.

I am also adding stub ribs where the bass block mounts to the lower wing. This piece is only supported by a small lite ply web and balsa sheeting and is not tied into the spar. Again, very little weight added.

I will probably reinforce all the cabane screw hard-points with 1/32 birch ply (including fuse, cabane, wing). I have found this material to add an exceptional amount of strength for it's weight in high stress areas. There's plenty of scrap in the kit too.

I'll use two servos in the wing but one, conventionally mounted, for the elevator. I like dual ny-rods with plenty of supports and no inner rod protruding. Maybe I'll look at dual carbon rods.

Oh yea, I'll dowel and glass the fire wall mounting.

I suspect all my mods will amount to less than 4 oz (3% of a/c weight).

That's all for now.

It worked fine. The airplane is long gone, sold and since crashed, but I flew it for about a year. It would not pass the muster of today's "3D" mongers, but it was a real nice-flying model with few bad habits.

I put that same prop on a Super AeroMaster bipe with a YS 120; good grief, did that thing go vertical... it was one of my all-time favorite models, but I don't think I'd like to build another one. It was a box full of sticks, sheets, and blocks.

Steve