4-stroke engine for pattern
 

Hi, not sure if I should be posting this question here or under the engine forums, but here goes...
Has anyone used ASP (Magnum / SC) engines for pattern flying? I have a 70-inch pattern model with an OS 140 RX on it but just cant get this engine to run properly, so I want to use a 4-stroke. Being on a bit of a budget, I cant go for YS or OS (and Ihave heard too many gripes about YS anyway). The ASP engines seem to be the same engines as Magnum and SC, both of which seem to get good reviews. I am thinking of the ASP180 four-stroke.
Thanks everyone.

RE: 4-stroke engine for pattern
 

For a 70-inch wingspan model, a 4-stroke 1.80 is very heavy![X(]

Is the 1.40RX new? Are you using a pump? Where is the fuel tank located? Plumbing completely sound? Right plug? Carb high and low settings correct? Right fuel?

Maybe figure out why the 1.40 2C isn't working...:eek:

RE: 4-stroke engine for pattern
 

hi cmoulder. the engine was bought lightly used, and i replaced both crankshaft bearings. it has its own pump in the backplate. the tank is on the airplane's CG, with the clunk being around 14 inches from the carb (12 inches from the pump). plumbing all new. OS 'F' plug, and 20% nitro fuel (with 20% synthetic oil) (Byron Fuels).
Unfortunately I have seen so many posts about this engine being very difficult to get running, that I'm giving up on it in favour of a new stroker.
I just need to know whether anyone has used these engines for pattern flying.
Thanks for your input.
Chris.

RE: 4-stroke engine for pattern
 

That really is surprising. The OS 1.40RX is one of the easiest engines to get running correctly. All of the ones I had were sweet hearts. I will say I'm not a fan of the Byron fuels for it as I don't think their lubricants are as good as some of the others, but it should still run OK. Prop it light with a 17X12 and go fly. What are the problems you are having making it run?

Arch

RE: 4-stroke engine for pattern
 

Try it with an OS 8 plug. OS F is for 4-strokes!

Also run 10% nitro, 18% syn oil.

RE: 4-stroke engine for pattern
 

After many years of running the 1.40RX's I wouldnt run 10% fuel. It really likes 15% better, especially for idle. The 2 best plugs I found were the KB-1L and the OS F. I personally ran the 1L's as they seemed to last forever and worked great.

Arch

RE: 4-stroke engine for pattern
 

Going to a 4-stroke will cause you more issues. The engines you quote are garbage and you'll be dissapointed if you buy one.

Stick with the 1.40Rx and get some help from an experienced user of the engine. It's very hard to fix issues over the net.

I recently sold my Pinnacle with 1.40Rx and it was a very reliable combination. In pattern, reliability is of paramount importance! There's no point having the most powerful engine/set-up if it doesn't finish a sequence.... The OS 1.40 RX while not the most powerful engine in pattern, it is extremely reliable.

This was my set-up:

15% nitro and 18% quality synthetic oil. I used the thicker viscosity oil not the thin stuff they use on YS engines.
I used OS No. 8 and Type F. The F seems to work very well and last longer. Use an F type.
I used an APC 17 x 12 standard prop. Has great pulling power! My engine was doing 8100 rpm on this prop.
I used the standard OS/Hatori Pipe and header. The header had 10mm cut off it and a 5mm gap between the header and pipe. This gives you a reference for pipe length.
Tank was a 14oz Dubro on the CG with an OS one way check valve on the vent line. Stops the fuel running out all over the place from the vent.
Use quality bearings in the engine and leave the rubber seals in place on both bearings. I used SKF and they lasted forever. Cheap bearings will more than likely give you issues.

That's about it I think.

Persevere with the OS. They are a great long lasting engine.

Cheers
Jason.

RE: 4-stroke engine for pattern
 

I'm with Jason. I've had 2 OS 1.40's and have run them on pipes and mufflers with equally good results. In fact the easiest set up is a muffler and a 17-10 or 17-12 prop. You don't have to worry about a tuned pipe and getting that set up correctly, just pretend it's a just a big OS 46.

RE: 4-stroke engine for pattern
 

I love my 140.

Pure methanol powered happyness. I think all the problems everyone has can be attributed to low nitro content (don't be so cheap! a minimum of 15%) and old, clapped out bearings giving funny midranges.

Mine hasn't missed a beat. (truth be told it did, but I hadn't changed my needle settings in over a year of flying. go figure:P)

RE: 4-stroke engine for pattern
 

Chispoulton; What's your plane? How much it weigths? Maybe a OS1.20 III (pump version) is what you need; good price/power/trust ratio. Otherwise consider tha SAITO engines; are not so cheap but there are some gas versions on 4 stroke.
Cheers!

RE: 4-stroke engine for pattern
 

Rendegade, maybe you missed my post - I'm using 20% nitro with 20% synthetic oil, and have put new bearings in the engine, but I still cant get it to run properly. I'm not using a fullblown tuned pipe as it wont fit my plane. I'm using a throttle pipe instead, from Weston UK.
The plane is an Elation 140 desinged by Steve Dunning of Elation Models in England. All-up weight is 10.25 lbs dry.
I will keep trying.
Thanks everyone
Chris