hotrod180 wrote:I know the non-geared O-435 is considered kind of a boat anchor, but I wonder why Lycoming never produced a non-geared O-480. It would fill a hole between the 360 & the 540, and would be comparable to the iconic Continental 470.

What's the horsepower on the GO480-- 270 or so?

I believe 295-315 hp or something close to that

A1Skinner wrote:Isn't the 540 comparable to the 470? Very similar hps. 235 vs 230 for NA and both 260 for injected. Is there much of a hole to fill for a 480??

Depends on what you call a hole. Not counting the old O-435 on the WW2-era Stinson L5, Lycoming doesn't have a non-geared engine between the 360 & the 540. An O-540 is just an O-360 x 1.5, an O-320 x 1.5 would be an O-480 and (based on the 150/160 factory rating of the 320) should be good for 225-240hp at similar rpms & with similar compression ratios. I don't understand why the O-540 is only 235 hp, kinda puny for 540 cubes-- should be good for 270hp based on the O-360's 180hp. Maybe lower compression and/or lower rpm?

hotrod180 wrote:.......What's the horsepower on the GO480-- 270 or so?

Checked the Lycoming GO-480 TCDS-- various dash number engines but takeoff hp (5 minute limit) is 260-295. I think the GO-480 powered Helio is 295.

hotrod180 wrote:

hotrod180 wrote:.......What's the horsepower on the GO480-- 270 or so?

Checked the Lycoming GO-480 TCDS-- various dash number engines but takeoff hp (5 minute limit) is 260-295. I think the GO-480 powered Helio is 295.

The Helio is 295 at 3500 RPM...

Brian.

Another cool Stinson. This one has a better motor with an IO 360.



Full span slot


Big a door


Cool sticks, overhead flap handle...


Big ol baggage

Wow, pretty radical!
The builder obviously likes Plexiglas, with the windows in the boot cowl left & right & even in the RH baggage door. I'm surprised he didn't put in skylights.

Left hand power quadrant is a pretty neat idea

Man...that's a lot of work that went into that one! Interesting in lots of ways!! I'd love to hear how it performs!!!
JH

The yellow and green Stinson looks to have a Twin Bonanza firewall fwd hung on the front. It could also be from an early Aero Commander.

The GO480 gets a bad rap for 2 reasons, 1-improper throttle inputs, 2- the super charged versions which were gernades. My Father operated a D-50 for skydiving with GO480g2d6 engines 295hp and had very few problems with them. The supercharged Twin Bo's climbed much faster but were maitenance hogs and engine pukers.

If I ever win the lottery, a Twin BO is on my short list of airplanes I would love to own. We operated out of a 2500' grass strip at gross weight with no problems, of course we were younger and dumber then. I would be much more conservative now.

I've heard the trick with geared engines is to always let the engine drive the airplane, not the other way around. And that about the worse thing you can do to them is a reduced-power (or power-off) descent followed by an immediate application of full throttle (as in a low pass at a fly-in)-- causes lots of gear lash action in the gearbox which isn't good for them.

hotrod180 wrote:I've heard the trick with geared engines is to always let the engine drive the airplane, not the other way around. And that about the worse thing you can do to them is a reduced-power (or power-off) descent followed by an immediate application of full throttle (as in a low pass at a fly-in)-- causes lots of gear lash action in the gearbox which isn't good for them.

I think the trick is being smooth! They will drive and they will follow, like you said the transition is the killer.

Just like a radial with a supercharger, smooth or you loose something!!

Off topic, but the above is exactly why so many have problems with a single Otter engine. The less power changes you do with a geared engine, the better, and like was said, smooth. Don't let the prop be driven is a good one also....but you need to be smooth. A huge deal with those too is to warm up gently. It's getting harder and harder to get pilots that can get that right anymore...so it's easier to go to a turbine on the Otter.
The only beef I have with a geared engine is the cost of overhaul. I love the way a pair of them sound, or even a single....but oh they seem to hurt the pocketbook when it comes overhaul time!
John

I've seen the John Deere colored experimental Stinson. It's owned by Wayne Alsworth, he is a Guardian pilot who works with my son. I'd like to see the other one. FAA says it's own by a guy named David Klum. I assume the pictures are taken at Merrill Field. Is that right? I have most of the parts to build another Stinson. The first time, I stayed certified with it but I have lot's of ideas and am interested in building another that is strictly experimental. I'd like to talk with David Klum if anyone knows how to get in contact with him.

Russ N6063M

I see that this aircraft which looks to be a formerly certificated Stinson 108 aircraft was registered as Experimental. How was that accomplished? I have a Stinson and want to do similar.

hotrod180 wrote:

A1Skinner wrote:Isn't the 540 comparable to the 470? Very similar hps. 235 vs 230 for NA and both 260 for injected. Is there much of a hole to fill for a 480??

Depends on what you call a hole. Not counting the old O-435 on the WW2-era Stinson L5, Lycoming doesn't have a non-geared engine between the 360 & the 540. An O-540 is just an O-360 x 1.5, an O-320 x 1.5 would be an O-480 and (based on the 150/160 factory rating of the 320) should be good for 225-240hp at similar rpms & with similar compression ratios. I don't understand why the O-540 is only 235 hp, kinda puny for 540 cubes-- should be good for 270hp based on the O-360's 180hp. Maybe lower compression and/or lower rpm?

You're comparing apples to oranges. Lycoming builds several models of the 540. Smallest is rated for 235....most common Maule engine. Then, there's a 260 hp version. The next step up is different engine entirely, cases different, cranks different, etc..... Still a 540, but rated at 300, though there's likely engines in between. They go all the way up to the TIO-540 rated at 350.

But, the point is, there are several completely different engines in that "Family" of engines. The 480 was a dead end, and probably a good choice.

MTV