anothercrashpilot

I'm going to build a GRUMMAN Ag-Cat Biplane with a 10' span and approx. 30 lbs.? I'm hearing WEAK results on the gt 80 , But nothing on the Fuji BT-86 ! I know it has about 1.5 more horse power but how about performance etc. ? and Mounts ,exhaust and the usual things to consider .! THANKs for any input.!

Antique

My Feedback: (4)

The WEAK results are from people who can't or won't read the instructions regarding prop size...Running 9000 rpm in the air, One of those weak GT80s will pull a 100 inch 25 lb formula One racer about 140 mph....STOCK....
Check out parts prices for both......
Both will benefit from aftermarket mufflers, the stockers are too restricted....
GT80 specs are on the Toni_Clark website...
This reply OK with you, Sinergy ? ......................................

Tired Old Man

My Feedback: (1)

Jake Ruddy

My Feedback: (40)

Of course it is...

Would I be suggesting Fuji?

Tired Old Man

My Feedback: (1)

I'd like to know whose h/p numbers he is using. Fuji's? Then again, all their engines are marketed with numerical designations that are clearly representative of their actual size, right? Like the Fuji 50?[sm=71_71.gif]

Me thinks the GT 80 should be re-visited and a search for some factual information from people that know what they're doing, rather than from those that are stumbling in the dark, be requested before a decision is made.

Robotech

My Feedback: (9)

A friend of mine has a Fuji 86 in his H9 Extra. I had a GT80 in my H9 Sukhoi when I first got it. The GT 80 would out pull the Fujij hands down. I had unlimited accelerating vertical, his falls out in a climb after a hundred feet or so. No comparison really. Both planes were within a half a pound of each other.

He flips and flips, choke on, pressure valve open, flip flip flip. After a few minutes it would finally bark. Flip, flip, flip, flip... dang choke again. I would choke the GT80, pull back on the spring starter and it would pop in two pulls. Choke off, two more pulls on the prop and it's time to fly.

gastech

10' span ag-cat...scale?...if so, where did you get the plans? I MUST know........

anothercrashpilot

Thanks for the Input guys ! I'm leaning back to the GT-80 ,Which is what I expected ! I just hadn't heard ANYTHING on the fuji before ![8D]

tkg

My Feedback: (1)

GT-80, is about 100 rpm stronger than the BT-86 with the same aftermarket mufflers (J&A Engerring) and the same prop.
Its a bunch easier to start as the choke on the BT-86 is a major PIA

anothercrashpilot

THIS is the type of input I need ! The GT is also a much cleaner looking engine! And TOO much IS better than not enough ! THANKs AGAIN !

Antique

My Feedback: (4)

If you want more power cheaper, a 3W80-xi will outdo either of the others, but it's a rear carb single and shakes some...$600.....
The twins are so smooth you can hardly feel the vibration with the engines running...

anothercrashpilot

THAT is part of my dilema too.! IS a GT-80 going to BE big enough ? 30 lbs. is a rough guess . THE original 90" span is to be around 20 lbs. with a Quadra . SO at 120" I'm not possitive ! And I haven't gotten my kit yet or seen the enlarged plans to get a better idea . And I would preffer to have a smooth twin . I DON'T plan on any 3-D with it, BUT, I don't want it to ONLY go HORIZONTAL ! Some basic scale maneuvers would be fine ! But not Lacking ! THANKs !

Antique

My Feedback: (4)

No lack of vertical with the G80s in our 25 lb F1GT Kelly and GR7 race planes...We sport flew ours, hammerheads, inside and outside loops, knife edge, inverted, no problems...
Don't know about a draggy 30 lb bipe...It will have 40+ lbs thrust with a 24-10, more with a 26-8...Should do just fine....

anothercrashpilot

SOUNDS good with the expected 26" prop. .. I plan on putting a dummy radial on the 12" firewall so I'll be covering 14-16" and have to keep decent gaps between cylinders ..