Running in one of these engines on a RV-4 Great planes. Sounds really good so far! I have an APC 15-6 prop on the front. I have one tank of fuel run through it. Can any one tell me what rpm I can expect out of this combo when the engine is ready to run for a first flight??[8D]

Well, I have the 1.20 AX and keep the RPM below 10K. I don't need the speed, I need the power. So, I prop it for power and not speed, meaning a power pitch (low number) and a large diameter.

I fly with a 15-8 or a 16-6. Not that I would recommend that prop for your 95 AX, however, it all depends on what kind of flying you want to do. With either of those props, I can pretty much pull to vertical and climb straight up.

Speed is not important to me as much as pulling power. As they say, stump pullers.

Prop it to whatever you want to do. You have a decent prop on it, so if it flys well with what you already have, then make adjustments as you see fit and move up or down in pitch and diameter as you see fit until you get what you want. No one can really recommend a prop for your plane/engine combination. And, as said, you already have one that it flys with, so you definitely have a starting point.

Hey, ask John Buckner about his prop collection some time. I'm sure he will show you the picture. You too can get a wall decorated with props!!! And with that sort of selection, you can do something that we all do.. play around some afternoon with a box full of props until you have one that suites your needs.

CGr.

I would expect about 9,500 RPM. In reality I would peak the engine, richen three clicks, fly, and not worry about the math.</p>

Yeah, when I say I keep the RPM below 10K, in actuality, I prop it to fly the way I want it to fly and get RPM's that hover around 9,500 - 10,000. I tune it the way I always tune it and that's the RPM I get out of it, and it flys just fine and is pretty quiet.

CGr.

With the first tank I was getting a touch over 9300 rpm which I think is pretty good for a 15" prop on the first run. I found a MAS 14-7 and will see how that runs.[8D]

That's quite good. I'de say you have a combination of engine, prop, rpm and plane ready to go. Let us know how it goes.

I picked up some Fox w/idle bar plugs and some more fuel. Hopefully will have a combination engine/plane/flight report in a few days. [8D]

It comes with a basic OS8 plug which is just fine for that engine. I've been using that plug on my OS AX engines, both upright and inverted, as well as S&W 15% nitro 20% oil blend fuel for years now. The fuel is no big deal, any quality fuel is just fine.. you may find some blends are better in your location and altitude, I don't know what that is, but I swear by S&W 15%. I'm sure there will be some debate about that, though, there always is.

Hi Dick, I won't debate the fuel with you at all. I buy what ever is on sale and for the most part that is Power Master or Wild Cat 15% nitro and 18% oil. WC is 16% oil so I bump it up a bit with a couple ounces of Klotz. I do like blended oils tough.
I do question the need for an idle bar plug though. I have used them on old worn out engines in the past but it takes a lot to ever beat the OS #8 in any good engine.There are other good plugs out there but you can't beat the old #8 for a two cycle.

Hi Gene.

The only real reason I like S&W, well, two reasons.. I was "brought up" on it and because my instructor used it.. ok, four reasons.. the local hobby shop carried it and the shop was just a couple miles from the house and field, and because S&W is a "short" drive from here. We often get together and buy it by the truck-load and save a few bucks.

Other than that, well, I'd use whatever came across the counter top. I don't really have a "scientific" preference.

As far as glow plugs is concerned, well, the OS AX's seem to come with the OS8 so I pretty much stick with it.

Dick.

Thankx guys guys for the info. The engine seems to run great on the OS8 on the ground but may switch to the Fox if it dies on me in the air.[8D]

If it quits in flight, I would carefully check the LS and HS tune before changing a glow plug. I've gone through all that before as most of us have. Finding that sweet spot with tuning the engine is difficult at times. It changes with the weather.. as does my left knee.. ouch!! [:@]

But, whatever floats your boat.. getting it up and flying to your satisfaction is what's important.

CGr.

Morning CG
Out club uses the S&W fuel as we buy it by the drum. 15% full syn. Hey, lost 48#s almost getting to fighting weight.

OK, engine and flight report: I switched props to a 14-7 MAS profile prop to try to get a few more rpms. After some low speed needle valve tweaking I managed a steady idle of around 2700 rpm with an instant response even after a 1 minute idle to a WOT rpm of 9800. I was hoping to see 10,000. I didn't make it but its very close! taxied out and tried a take off but the plane torqued to the right on the hard surface run way. I stopped and switched to the grass and tried it again. This time I was going to full throttle and the plane jumped off the ground when I hit about 1/3 throttle and kept on going into a nice fast climb out as I increased throttle! Very stable and easy to control. I made a turn back and let the controls go to see how it would do. I needed 3 clicks of down elevator and thats all! Tried a few turns and rolls. The plane is pretty fast at 3/4 throttle and very stable. I throttled down to a 1/4 and the plane would still roll with out dropping altitude. Flew for 5 minutes and tried a landing. The plane floated off more speed than I expected(no flaps) and had to add a bit of throttle to make the runway. Finished the landing with out even a slight bounce and followed by applause from the other pilots watching!. This plane and engine combo are both awesome! Highly recomended for a larger plane that handles like a 60 size sport plane!! Cheers!!

Good stuff!!

CGr.

A 2700 RPM idle is fast, but if it works...great.

The maiden flight was on the 3d tank of fuel and I didn't want the engine to quit on me. I plan on reducing the idle a bit before the next flight but have nothing to complain about so far.

I have a 95AX, pulled hard. Seams to run a little rich in the mid range, but runs good. No dead sticks. I would buy another if they DIDNT cost more than a DLE-20.

And the DLE-20 is only 2 1/2 oz more and pulls the same prop as a 120AX.