cfv007

My Feedback: (5)

I installed a velocity stack on my g-62 and although the engine seemed to be running fine on the ground as soon as I was airborn the engine ran erratically. I figured it musta been running rich now since the stack is supposed to keep fuel from being sucked out of the carb venturi via the air passing over it.

My question is: How do you set the needles while the plane is on the ground since it seems that the engine runs differently once the plane is flying?

Also .... my stack is cut at an angle, should the longest end of the angled stack face to the front of the plane or the back?

Thanks,
Chuck

pcm

My Feedback: (13)

The longest angle to the rear. So it forces air into the carb as you fly.

w8ye

My Feedback: (16)

First try the carb extension the way that pcm says. That's the normal way. But if you still have trouble, you may have to turn it around a bit. The airflow is different on each plane and you may even have to put the long part to the front?

Make it run correctly.

Good luck,

Jim

Geistware

My Feedback: (16)

Will your stack be in cowl or outside?
If it is outside the above is correct.
If it is in cowl, you may want to address different angles to see which is best. With my Giles, my installation is in cowl and I have it pointing down!

cfv007

My Feedback: (5)

My stack and carb are outside the cowl. I will try it first with the longest end toward the rear like pcm said. Seems like it would sorta ram the air and fuel down into the carb.

But what about setting the needles?

w8ye

My Feedback: (16)

You will have to reset them on the ground. And also you may have to re-adjust them a little for in the air, if you can detect a slight change, bring it back in and try moving the high speed a little. You will have them set before youy know it and rarely have to move the needles again.

good luck,

Jim

Geistware

My Feedback: (16)

The stack has two purposes. I learned this from asking many people on the net and then validating what I was told for myself.

First the stack reduces the suction at the opening of the carb so that air and fuel are not drawn out of the carb during mid-throttle operations. Second, the ram air effect re-enforces the amount of fuel-air charge in the engine. These two effects will improve engine performance.

cfv007

My Feedback: (5)

Thanks everyone ... for the help!

Chuck

TwoWings-RCU

My Feedback: (5)

Just went through this myself. Have a G-62 on a 29# Sea Fury that was running fine but came back covered in oil from the carb blow-by. Put a stack on it to help the problem and was rewarded by 400 less RPM on the same prop and fuel. 400 RPM on a 22-10 prop makes a big difference.
I leaned the needle a 1/16 of a turn and got back about 200RPM , so I screwed her in another 1/16th and got back to my old groumd RPM. Will fly this week end and let you know how the performance is in the air. This plane was clocked by radar at 95mph on a flat level pass so we'll see how she does.
By the way, the oil blow-by problem went away on the ground. This engine has the short riser block between the carb and cylinder which produces more fuel blow back than the stock version. The blow back is a combination of vacuum at the the entrance to the carb due to passing air and the intake timming of the G-62. Any engine with sub-piston induction will by nature blow some of the fresh incoming charge back into the carb. My situation was made worse due to the short riser block used to keep the carb from being right up against the cowl.

Lou

cfv007

My Feedback: (5)

Let me know how its running after you fly next ok? What rpm were you turning prior to putting the stack on? What prop are you using? Zinger? Zinger Pro? Menz? I was using a plain old Zinger 22x10 but couldnt get much more than 6000 rpms. For now Im using a 22x8 and getting 6800. Im not sure which prop I should really be using but the 22x10 seems to lug the motor.

Chuck

Geistware

My Feedback: (16)

I tried a Menz 19/10 and Zinger 20/8 and found a 1300 RPM difference!

Big_Bird

My Feedback: (1)

Chuck, just by chance, I was out in the back yard this afternoon tacking my velocity stack equiped G-62 on a plain old Zinger 22x10. By leaning the high speed needle way out (3/4 turn open) I could get 6900 rpm. I backed the needle out 1/4 turn and had 6600 rpm. That's where I left it. I'm running Klotz KL-300 synthetic (50:1) and 87 octane regular gas. The engine is well broken in. I can pick up about 800 rpm with a Menz 22x10 Ultra but I'm not sure I really like the extra rpm. Vibration goes up with more rpm even with a carefully balanced prop.

Ken

TwoWings-RCU

My Feedback: (5)

I have been using the Master Air Screw 22 X 10(I like the thicker airfoil they have) and was getting 6500 rpm. The engine/plane were very happy with this combo. Remember that I am pulling around 29# of war bird with the G-62. Not looking for the highest rpm but the best thrust. I prop my engines to run in the max. torque range(this will probably set off some more comments) on big war birds. Big Bird said it very well. The extra rpm's just seem to create more vibration and noise w/o any gain in performance on my large heavy war birds.
Going out this AM, will let you know the results.

Forgot to add, I am running AMSOIL @ 60-1 and this G-62 has about 25 flights on it (about 5 hrs.).

cfv007

My Feedback: (5)

What muffler are you guys running? Mine is the stock one. I was told by someone to drill 2-3 3/8" holes in the baffle inside the muffler. He said to drill one at a time and recheck the rpms. With one hole I picked up 200 rpms. I drilled a second hole and it went back down to about 6000 tops with my 22x10 Zing. I notice there wasnt enough room in there to get another hole in there so I just used my Dremel to open the space between the two holes I had made thus ending up with one oblong hole. Again I had no gain in rpms ... still about 6000. So now I am getting another stock muffler to start over with. Maybe just drill one hole and leave it at that. I know they have been drilling out the stock mufflers on the 80 twin to pick up quite a bit in rpms.

Chuck

cfv007

My Feedback: (5)

oh yea ... where do I order the Amsoil?? Is it all synthetic?

Big_Bird

My Feedback: (1)

It's all synthetic. Look in your local business pages for an Amsoil dealer.

It's good stuff.

Ken

TwoWings-RCU

My Feedback: (5)

Flew the Sea Fury and was able to get back to about 6200 rpm before it just got too hot to keep foolin around with the engine. So. on a hot, humid day (93 degrees @ 85 % humidity) I got back most of what I lost by tweeking the HS needle. I really didn't want to lean it much because big war birds don't glide too well. So just work on your needle setting. Once you get where you want it to run, leave it alone.
AMSOIL is 100% syn. and really does a great job after your engine is broken in on 2-3 gallons of 32-1 petrolieum 2cyc. oil. I get mine from a guy that shows up at a swap meet I go to every March. Look them up on the net, I am sure they have distribution almost everywhere. You might try a motorcycle shop too.
One of the best benefits from the stack on my G-62 is now the btm. of the plane is clean and not covered in green oil slime. Plus I can now get an easy 15 min. flight from a 24 oz. tank with 5 min. of fuel to spare. Before I had about 10 min. and then it was drop the gear, flaps and land. Forgot to refuel about 2 weeks ago and got another 5 min. out of the tank before dead stick time. Was lucky that she quit up high so I could get her down w/o a problem. Needed a new pair of shorts though.
Almost forgot, I am running a Bennett muffler so no back pressure there. I have a friend who has a stock G-62 muffler with 3 3/8" tubes welded into the bottom of the muffler w/ the baffels hammered shut and welded up. Runs great and sounds better. May try that next year. Not going to fool around with my set-up anymore this year, just fly it.
Good luck,
Lou