I have one with an OS70FS. I was wondering if anyone out there has managed to 3d there Great planes ultimate biplane? Bottom line, will it hover if you mess around with the prop and engine? Maybe a lighter engine may help. If this is possible, please share the secret with me. I need this plane to go ballastic. With the OS70 and a 13x6 prop is a nice comfy plane...not wild. Mine weighs in at 7.5lbs dry. I guess its heavy

Anurag

I too have the GP Ultimate with OS 70. I only have 2 flights on it but from what I have seen I doubt it will hover well. Just too heavy of a plane. My Cap with the same engine will hover at around 3/4 stick. The Ultimate tailslides at the same setting. It is a great flying plane but lacks the size/power needed for good 3D. Almost lost it on the second flight when I tried hovering because it took so long to recover. I ended up exiting inverted with full throttle to get out of the stalled situation.

Good Luck, Phil (Mesa, AZ)

I agree, I have the same setup too and I doubt it would ever do 3D

I HAVE A GP BIPE WITH A SAITO 72 ON IT. THINKING IT WEIGHS IN AT ABOUT 6- 6 1/2 POUNDS. USING AN APC 13X6 NOW AND IT FLYS WELL BUT WONT BLAST OFF VERTICAL. HAVE A 14X4 PROP BUT HAVNT TRIED IT YET, NOT SURE ABOUT MAKING ENOUIGH SPEED WITH IT. I CAN GET IT INTO A HOVER BUT MY THUMBS PROBABLY DONT FLY WELL ENOUGH TO KEEP IT IN ONE. NEEDS ABOUT 75-90 PERCENT THROTTLE TO KEEP NOSE UP DEPENDING ON WIND CONDITIONS. IT WILL GO UP VERTICLAL WITH FULL POWER OUT OF STALL BUT WILL NOT CONTINUE STRAIGHT UP. THINKING ABOUT A SAITO 91 IN ITS PLACE, THAT SHOULD SOLVE ANY WEIGHT, DRAG, NO ENOUGH JUICE PROBLEM.....

I'm not sure, but .70 4 Stroke sounds a bit small to hold 7+ pounds vert.

The specs on this plane (this is the 40 size?) say that it should only be 6.5 pounds max.
The OS 70 4 Stroke only weighs 6 oz. more than the .46 2 Stroke, so I don't think that the engine is to blame, but it seems you do have a pound to much in there somewhere.

Some things to look at:
Spinner, can you find a lighter one?
Do you have ballast weights? Get rid of them...move stuff to compensate.
Lighter wheels.

ok, i weighed my biple again and its 6.6lbs..and not 7.5lbs as I previously thought. What rpms am i looking at with 10% fuel and a 13x6 prop. The vertical in this plane really sucks. The engine is the OS70 FS.

Anurag

I don't have the GP Ultimate - but I do have a CG Ultimate that's 7lbs. It can hover with a ST 90 pulling a 15x8 APC, but doesn't have that much power to spare for pulling vertical out of the hover. So, if you have an Ultimate that weighs the about same as mine does, but has a significantly smaller engine then I would hazzard a guess that its not going to hover well.

Gordon

what if i put a YS 63 on the ultimate bipe? the nose weight will reduce and so will the overall weight. Moreover, the YS63 puts out substantially more HP than the os70 does. Any comments on this plan?

What about a 91fx? the os70 is 20.3 oz and the 91fx is 19.3 oz...so basically we are getting more power and reduced weight.

anurag

I doubt that swithching brands of .70 4 strokes will help. Mine has the OS and no lead. So adding a lighter engine will require adding lead. Unless you want to get real creative with receiver/battery placement. My vertical pretty much sucks too, 13x6 prop. I would go larger in diameter but I only have about 1" ground clearance as it is. I think a lot of it has to do with the THICK airfoil. I am almost certain that this creates a lot of unwanted drag. It does keep the plane stable at slow speeds but slow is all this plane seems to be. Don't get me wrong, it is a blast to fly this plane, but others are much more capable. My Cap, with the same motor, is an entirely different beast. Verticle preformance is sweet. My ultimate will do a torque roll, but it descends during the maneuver. Looks scale while it does this but there is no hope of it pulling vertical out of the maneuver.

Good Luck, Phil

I TRIED A 14X4 PROP YESTERDAY ON MY BIPE INSTEAD OF THE 13X6...DIDNT HELP AND SWITCHED BACK TO THE APC 13X6. HAVE A SAITO 72 IN NOSE AND MOUNTED THE ELEV SERVO IN TAIL AND USED A PULL-PULL FOR RUDDER , AND HAVE MORE ROOM TO MOVE BATTERY INSIDE OF FUSE OF PLANE......I DID SEAL THE HINGE GAPS AND IT DID MAKE A DIFFERENCE FLYING, BETTER ROLLS FASTER AND QUICKER RESPONSE. I SAY URE HEADING TOWARDS MORE POWER, SAITO 91. THE YS 63 OR FX 91 WILL ALSO GET THE NEEDED EXTRA POWER. A 14 PROP FITS MINE WITH 3 INCH WHEELS AND NO WHEEL PANTS WITH ROOM TO SPARE. ANYONE OUT THERE WITH A SAITO 91 CARE TO MENTION HOW THE VERTICAL IS.....?

My Ultimate bipe also torques at the top of its vertical limit on FULL THROTTLE and then tail slides back...looks very scale, but we guys are used to a different beast lately with planes torquing at 50% throttle and rocketing out of it at our will.

I just love this little plane too much...3d or no 3d.

Anurag

I have been flying a world Models 120 Ultimate for quite a long time now. This is my second one. Don't ask about the first. The dimensions between the Goldberg and the World planes are within 1/4" of each other

My Ultimate weighs in at 9 1/2 lbs. wet with a Saito 1.50GK. Using a Zinger 16/6 prop and 10% fuel, this plane will hover and torque roll all day and climb out straight up. I have noticed that the guys flying the Goldberg Ultimates always seem to stay in the 70 to 90 range with their 4 strokes. Your engines are too small for 3D. 3D requires POWER!! Step up to a 1.20 size engine on the Goldberg planes and enter a new flight envelope.

Don't worry about the added weight, the engine will pull itself just fine. Your Ultimate will 3D just fine with enough power and control throws. Remember that it's a biplane and has some differences in the stall from a mono wing and encounters a few limitations because of this. It also has a much higher wing loading than a mono wing.

Silversurfer