SST

My Feedback: (2)

I've had 4 non-revlite Norvel .049s now for 6 years or so, but never tried to run 'em till now. Anyways I just finished running one on the bench and here's what I got:

16,500 rpm steady on 25% Byron fuel w/a black Cox 5X3. I first ran 4oz. of 15% Omega, followed by the Byron (2oz so far). One head shim. I was running 2 clicks rich from a peak of 17,300. Not much difference in rpm between the two fuels, but the Byron seemed to give a smoother run.

This seems a bit slow to me, but I'm not using them in any high power situations. One will go into a Goldberg Ranger 42 (I flew one years ago on a cox reedie and full-size radio gear), and the other will go on a Astro Mini Challenger converted from E-power to glow.

So what do you think. Am I missing something here or is this par for the course for so little time on this engine. I realize that these motors take forever to get well broken in. Thanks.

Lynn S

Doug,
My .049 big mig runs 16,600 with the cox 5x3. I think this prop can really "hook up" as Dickeybird says.
It is pulling my Extra plenty fast at that rpm.
I found that my engine needs more castor that the stock Byrons 16%
I add castor I bought at walmart pharmacy to get it up to 20% castor.
I found that my engine would go dead after about 2 min in the air without the extra castor oil. I have not had that problem since I started adding more castor to the fuel.

phuffstatler

My Feedback: (20)

I need to tach my Big Migs, but here in Texas, I run no shims and the Norvel 25% fuel. Pulling a MA 5x4 cut down to about 4.75x4. Flies that big 'ol Star Cruiser around at about 40-50 mph (I think), and it weighs 20 oz. with about 300 sq in of wing. Once it 'gets on step' it moves pretty well.

I think the Ranger 42 (Gosh, I wish I had another one, mine flew away in Denver back in '82) will fly around ok, but don't expect a lot of aerobatics out of it. I've never seen a Mini-Challenger before, but without those batteries it was meant for, I'd say it would float around really nice.

SST

My Feedback: (2)

I guess I should have mentioned the Mini Challenger is a 54" sailplane. It's very light, and I plan to use a big Texaco type prop to slow it down, lest the wings tear off or something.

2fast4u

My Feedback: (5)

Kinda depends on if they are AME or BIG MIG engines. The AME will turn a little harder than the Big Mig. Your #'s sound ok to me. It's just an .049. I run 25% nitro and 20% oil (all synthetic) in all of mine. As long as you have enough oil, they run great and seem to get better with age. All of mine have.

Just remember that the Norvels (all of them as far as I can tell) like RPM's, so don't lug a big prop on them. Let the rpm stay high and the engine will run cooler and better. I have had 3 .061's that liked to turn around 28K at launch and would unload from there. They have all lasted over 2 years each before any damage, even at that high rpm.

Just let um run, and they will be fine.....

MikeSell

My Feedback: (2)

You are flying slow flying planes so don't try to fly them too fast. The faster a prop turns while it moves slowly thru the air the more its slipping or just creating turbulence. If high rpm is your goal even a slow air speed try lower pitch numbers. If matching your prop to the speed of your plane for most efficency larger diameter at lower rpm should be your target.
A prop is most efficent at 325-375 mph tip speed. A wider tip grabs on to more air than a narrow one. Larger diameter props equate to more thrust. Smaller diameter props equate to less drag.
The numbers sound about right to me. Lotsa oil makes it run better and longer.

SST

My Feedback: (2)

Just came in from running another one (the one for the Mini Challenger). This one got three shims, 15% and a Cox gray 8X4. Turned 6500 and ran 9 minutes on 1/2 oz. of fuel! I've put a total of 4 oz. through it so far. This works out to around 25mph, plenty for this featherweight glider. It really sounds neat, and the flywheel effect of that big ol' prop just makes it roll through the occasional stumble that would kill one with a small prop. Cool!