My dad has had a us 41 sitting in the shed for several years now and just the other day decided to buy an arf cessna 182 for it. My question is what size and type of prop will he need and what type of fuel to oil mix do we need for running in and then normal running. This will be our first gasser, have been flying nitro now for 14 years so the plane size is not a problem its just a new engine setup that we are unsure of thanks in advance

Using an 18x8 or a 20x6 prop might be a good starting point. Regarding what oil and ratios to use, this topic has been beaten to death several times over right here on this forum, so doing a search should turn up all the info you could ever want.

However, most everyone has a preferred brand and ratio that seems to work best for them, but just in case you need an answer right NOW, what I will say is that any good quality 2 stroke synthetic oil mixed with 87 octane gasoline as per the manufacturers recommendations of between a 32 - 50: 1 ratio will get the job done quite nicely.

Just a reminder, gas models need gas compatible fuel tubing and tank stoppers such as the Hayes tubing and Dubro stopper. Felt filtered clunks are also a very effective way of ensuring that clean fuel reaches the carb.

Karol

i also have a us 41 i fly mine with a zinger 18x8 it seems happy with it your plane may differ, the 41 does need some break in time bolt it to a stand and try to run a gallon or two of fuel through it before putting it in the plane i recommend using only a good synthetic oil in it ,zenoah , amsoil , or klotz are all fine , i would recommend mixing it at 4 ounces to one gallon on a new engine and after break in period reduce it to 3 ounces per gallon from then on , good luck and have fun with it

I have been flying my US 41 for quite some time now on a GP Giant Stick. I am using a 40:1 mix with Stihl oil and a 20x8 Xoar prop. The US 41 has no trouble spinning that prop and is happily turning around 6800-6900 rpm. I have also used an 18x10 Pro Zinger and 20x10 Xoar. The engine runs great with either but the choice comes down to what you are happiest with on your particular airframe. Unfortunately, experimenting with these big props is rather expensive. Do yourself a favor, though, and buy good props. The better wood props don't cost much more than the cheap ones. I would stay away from the zingers in all forms. Haven't tried an APC but I haven't heard enough encouraging about them to make me want to. I have been warned to prop the engine to below 8000 rpm top end so that is why I avoid the smaller props.

Brian

You didn't mention what size this Cessna is, but must be a doozy. If an 18-20 inch prop gives you any ground clearance problems, a 16-8 three blade will work well also, and not be "non-scale" for a 182. Like said above, everybody has a favorite oil and mix ratio, but I like either Klotz at 40:1 or Amsoil at 50:1 with standard 87 octane gas. I've got about two years' service out of my US-41 so far without a glitch or whimper (except for the spring starter), and it runs better and better. I have used as big as a 22-6 prop, but it was really too much, I have a 20-6 Dynathrust on it now and it hauls a 22 pound plane around real good.

Does yours have a spring starter? My spring broke after a year, but it seems to run better without it hanging on in back. It's not an easy engine to flip start, needs a lot of rpm for the mag to fire the plug, but an electric starter makes it a breeze.

I have a US 41, still never been run, just getting ready to make a stand to put it on to break it in.

But I happen to have the original Owner's Manual, it says the following:

Your engine has been factory tested with an 18x8 prop at 7,000 RPM. After break-in, we recommend an 18x10 or 18x12 prop, however, othe rprops can be use dupon experimentation, egines develop optimal power between 7200 and 7700 RPM.

One-way bearing should be lightly oiled with 30 weight oil every 15 to 20 hours and/or prior to storing engine for any length of time.

The general operating fuel mix recommended is 32:1 using 87 octane reg unleaded fuel and high quality two-cycle engine oil. Always mix well.