Never doubted it. I know a thorough guy when I see one.

If i was going to slot the follower, I would cut it in a sprial. Then you would not wear a groove into the case.

I had a chance to run the engine today. It started up nicely and runs fine. The needles are sensitive on 0% nitro fuel. Idle transition is not great. I can't richen it enough to slam the throttle open without it stumbling or quiting. If I do richen it, the idle is sloppy. It will idle very slowly, but not at a mixture setting that allows any sort of transition. It seems the carb gets very rich at extremely low throttle settings. I think the carb is beyond it's normal idle range, there is such a small opening that it's surprising it runs. I pulled the rocker cover after about ten minutes of tuning and it was nice and wet, much more oil than it ever has in stock form. The fuel had only 8% oil, balance methanol.

I have added a page on my site now. I'll add a photo tonight of the installation in the test airframe. I managed to get the ignition and fuel tank into the nose of an Avistar 40. I hope to fly it and get some performance figures tomorrow.

Greg

Greg, I've been following this with great interest and actually made a velocity stack from the stainless tube on a (dead) Hobbico SuperShot. I expanded the tube a little with the shaft end of an appropriately sized drill bit. It is a fairly hard press fit with red LockTite, it's the second one I've done this way, they never offer to come off.

I'll probably end up making a stack from aluminum bar.

The carb tuned well even tough it was sensitive. One click rich on the main needle would give it a mid range burble in the air. It never quit and I love it. The guys that were out today liked it too.

I just updated my webpage with a video.

Greg

Hi, I'm planning to get the FSa 56 for a Kyosho Spitfire 40. Due to the new lubrication mechanism I have some doubts if the lubrication is working if the engine is mounted upside down. Has anybody operating experience running this engine upside down ?

Originally Posted by boetzi

Hi, I'm planning to get the FSa 56 for a Kyosho Spitfire 40. Due to the new lubrication mechanism I have some doubts if the lubrication is working if the engine is mounted upside down. Has anybody operating experience running this engine upside down ?

I'm running mine upside down in a Topflight Elder no problems to report.

Inverted mounting should make the lubrication system work even better. You get a gravity assist to get the lube up the lifter covers and into the valve cover.

McD

Kingsflyer,
Have you tried the 56a on a 14x5 prop? It should be the same loading as the 13x6. I'm currently flying the OS .48 on a Goldberg Tiger2 with a 12x5 and it has the torque to do outside loops. I had a magnum 52 on the tiger and it barely flew. I have a new 56 that I was going to put on a Sig Kadet aerial photography plane.

dMac

I'm still flying the 13x6 Master Airscrew S2 prop on my Akro. I'm sure a 14x4 would work as well, but I like the extra speed of the 6 pitch for Knife edge.
Mike McD

I have the OS 56 FS-a, bought new and run in with about a gallon of fuel last December. Used it on a Kyosho warbird, wasn't impressed with the performance and switched to the 55 AX.

After 6 months of storage in a sealed bag with after run oil, I want to use the 56a again. I checked the valve clearance, installed a new F plug and tested it last weekend: it fired up OK with electric starter and it produced 8,500 RPM on APC 12x6 at WOT (200 RPM rich of max). Used 15% Cool Power, rather hot but dry day.

I also noted that when the engine's cold I can turn the prop and there's almost no compression (just the hissing sound as the valves open and close), no comparison to my .91 Surpass II which has a lot of compression when cold.

Is this how the FS-a behaves or there's a problem? The RPMs I get are 15-20% less than the test numbers reported on page 1, what could be the problem?

We have hot dry days here ,I had my 56a in an 8lb CMPro Zero, had an APC 13x7 prop which seemed to give the best all round performance and it was pulling around 8900 RPM so your engine,s rpm sounds alittle on the low side..what altitude is your flying site ?.
I was running 20% nitro 13 % syn 5% castor mix.
Also I had an OS 52FS pipe fitted on this model , which is why it sounds alittle different from the 56a's ussual note.

Cheers Steffan.

Last flights of the Zero (3 min 30 sec)

I agree with Steffan. Your numbers sound low and you should have pretty good compression even when cold. You may need to send it back to OS for a checkup.
McD

anyone get the FSa-72?

Originally Posted by tora

anyone get the FSa-72?

Yep,

I have the .72a in my Big Stik 40 and its great.

Turns a 12x7 at 10,700rpm and pulls the plane around with plenty of power to spare.