The G-Mark .061 Family

Hi . I'm firing engines in a narrow belt of birches. It's the closest trees in the CzarDrill movie .
Yeah, the engine is running well despite the wrong fuel tank placement. From the bottom of the tank to the carburetor is about 7 cm (2.75 inches), and from the outgoing pipes (as shown in your picture) it's about 4.5 cm (1.77 inches).

Twin pistons so suction cycle is doubled that helps to keep the fuel line loaded
and ready to flow when gravity is trying to migrate it back into the fuel tank.

1/2A Nut wrote:Twin pistons so suction cycle is doubled that helps to keep the fuel line loaded...

It's a 2T boxer and the suction through both pistons is at same moment so I think it's not doubled . However, I may have misunderstood

I think one of mine did about 14500rpm on the APC 7x4 prop and 10% nitro, but I will have to check/find my notes from that time.

Are you really using a 7x3 prop?

Yes, I used 7x3 prop, additionality I tested an 8x3 prop and engine reaches about 10 000 RPM. Maybe my engine is in worse condition than yours.

That Bad Boy sounds Good !! There was just one on eBay for sale .

czarobest wrote:Yes, I used 7x3 prop, additionality I tested an 8x3 prop and engine reaches about 10 000 RPM. Maybe my engine is in worse condition than yours.

Well it is not a competition but 14500rpm on a 7x3 prop really isn't not much in terms power, that's kind of .061 engine territory (at least for a diesel engine).

You can check if the cylinders are running evenly by applying glow power to individual plugs with the engine running. That can sometimes reveal a bad plug (rpm goes up with power applied to that side).

I used two new OS A3 plugs, but thanks for advice .
Maybe it's because of that badly placed tank. I'll check next time .

A fellow modeller just told me that sometime ago he got a couple of small twin engines, he has not use for them nor collect engines. He offered them for a reasonable price.

Here are my new additions.

Very Nice , You got plans for them ?

getback wrote:Very Nice , You got plans for them ?

Possibly a Qee Tee for the .12 twin and a My o My for the 30, but in the short time they will be on the shelf with my other special engines.

Nice, very nice, you've got a rare pair, congrats. Just a passing comment, but would the .12 twin be a bit too much engine for a 36" span Q-Tee?

My Golden Bee on a good 6x3 prop was ample power for my Q-Tee, a Norvel Big Mig .061 turned it from a gentle schoolyard flyer into a fun sport plane.

Just my impression, but wouldn't a Hobby Shack 46" The Real Thing be the right ticket?

Thanks for sharing, and good luck on your rare to share exploits. I look forward to hearing about your experiences with your new engines.

GallopingGhostler wrote:Nice, very nice, you've got a rare pair, congrats. Just a passing comment, but would the .12 twin be a bit too much engine for a 36" span Q-Tee?

My Golden Bee on a good 6x3 prop was ample power for my Q-Tee, a Norvel Big Mig .061 turned it from a gentle schoolyard flyer into a fun sport plane.

Just my impression, but wouldn't a Hobby Shack 46" The Real Thing be the right ticket?

Thanks for sharing, and good luck on your rare to share exploits. I look forward to hearing about your experiences with your new engines.

The .12 might be too much for the Qee Tee but I fly at 7,200Ft and this little engine is not a powerhouse. I am also thinking on increasing the wingspan of the Qee Tee to 40 or 42".

I flew my Q-Tee at 6,500 feet elevation. Was surprised that the Golden Bee with Masters 6x3 prop flew it well. (Q-Tee has ample wing area, even with the decrease in ambient air pressure, plus, my R/C equipment and battery were reasonably lighter weight. OTOH, at sea level, I saw little difference in flight speeds between a 5.25x4 prop and a 6x3 prop. It became more pronounced at elevation. It struggled to lumber along with the 5.25x4 prop.)

Now I live at 4,300 feet elevation. The Norvel .061 Big Mig made it a hoot to fly.

But, I know what you mean about upping power to make up for the reduction in combustion by elevation.

GallopingGhostler wrote:I flew my Q-Tee at 6,500 feet elevation. Was surprised that the Golden Bee with Masters 6x3 prop flew it well. (Q-Tee has ample wing area, even with the decrease in ambient air pressure, plus, my R/C equipment and battery were reasonably lighter weight. OTOH, at sea level, I saw little difference in flight speeds between a 5.25x4 prop and a 6x3 prop. It became more pronounced at elevation. It struggled to lumber along with the 5.25x4 prop.)

Now I live at 4,300 feet elevation. The Norvel .061 Big Mig made it a hoot to fly.

But, I know what you mean about upping power to make up for the reduction in combustion by elevation.

Thinking about it, may be a Sterling Piper Tri Pacer will be also a good option, it is not easy to get a kit but the plans are in Outerzone and should not be difficult to scratch build.