O.S. .10FP R/C w/ muffler

Dang! If it wasn't for the dollar right now, I would gladly make an offer, as I have wanted one of these just to see for myself.

I have the control line version. When someone gave it to me it looked like it had hardly been run, although the screws were chewed out and prop drive missing. I got a new prop drive, screws and gaskets and it felt great, but once I fueled it and tried to start it I lost all compression. Tore it down & checked it out & it looks like the piston is all scored. No idea how that happened as I was careful to keep everything clean. Now it will only fire with an electric starter but just peters out. A piston & sleeve costs more than I could get another engine.
Mark, $35 is a good price but at $48AUD plus shipping I'll pass. I have enough Enya 09s & 15s to choose from if I had a plane to fit it to.

Rod.

Here is the test of this engine on Sceptreflight:

http://www.sceptreflight.com/Model%20Engine%20Tests/OS%20Max%2010.html

I also have 2, but 4-stroke OS Max 56 FS engines and these are really very good products, I assume the earlier 2-stroke OS Max 10 R/C must be of the same quality (if handled and maintained properly).

Just for reference I checked the COX 09 TeeDee test on the same site, and the peak performance of the COX - while roughly the same size or even smaller - is more than 2 times that of the OS Max.

http://www.sceptreflight.com/Model%20Engine%20Tests/Cox%20Tee%20Dee%2009.html

The linked engines test is for the much older engine from OS. After that they made the much better .10 FSR, while the engine from the OP is the even later .10 FP. The FP model is ABN construction and it is more powerful than the Cox .09 engine. The OS engine will make around 15800rpm on an APC 7x4 and 10% nitro. The OS engines really need a full castor fuel as their liners are prone to peeling their nickel layer. Here is what that looks like. From the outside you see a scored piston and the inside reveals that the nickel layer is coming off...

balogh wrote:Here is the test of this engine on Sceptreflight:

http://www.sceptreflight.com/Model%20Engine%20Tests/OS%20Max%2010.html

I also have 2, but 4-stroke OS Max 56 FS engines and these are really very good products, I assume the earlier 2-stroke OS Max 10 R/C must be of the same quality (if handled and maintained properly).

Just for reference I checked the COX 09 TeeDee test on the same site, and the peak performance of the COX - while roughly the same size or even smaller - is more than 2 times that of the OS Max.

http://www.sceptreflight.com/Model%20Engine%20Tests/Cox%20Tee%20Dee%2009.html

I'm not sure what you saying, twice of what? They're both great engines, but it hard to compare the two as one has no muffler or carb. If you're looking for a r/c engine the rpm difference on a typical prop (8x4) is only a couple thousand apart and you'd have a throttle. If you're flying u/c combat the Tee Dee would rock on a small prop.

The later FSR is a Schnuerle ported engine, i don't have specs in front of me but i think its would out spin a Tee Dee .09?

I compared the 0.28 bhp of the COX to the 0.14 bhp of the OS but did not note that the OS test was for an older version.

Anyways the 2 engines of the comparison are of the same production era of the early 60-s and the performance difference is striking even if one of them is handicapped with a muffler.

BTW here is the 10FSR test and it generates 0.275 bhp on 40% nitro without a muffler I. E some 2% less than the output of COX 09 with 10% less nitro
sceptreflight.net/Model Engine Tests/OS Max 10 FSR.html

The Cox TD numbers where recorded with >30% nitro, no muffler and a CL venturi.
Put a muffler, regular glow plug, and an RC carb on the Cox (i.e. an .09RC) and you will se very different numbers....

Kris you are right muffler and RC carb both will reduce the rpm but the top curve of the OS FSR where the COX outpeaks it was measured without a muffler on and with some 10% more nitro

Anyways I am just quoting test figures recorded by others so my assessment is as accurate as that of the literature. .

The FSR engine is a little low on the compression ratio in stock form, possibly aimed at the american market. The FP, which is the engine in question here, is a little stronger in stock form on low nitro fuels. By turning down the head of the FSR it will get close to the FP in terms of performance though.

The Cox .09 was once ahead in terms of performance but take a look at any modern engines (Fora and Profi etc) that are designed for the same purpose (i.e. a full bore for run for a limited time), and the difference in power is huge...

No doubt about that..the TD is a genuine 55 years old design for mass production wihout any subsequent major hop-ups for performance and once may have been a higher value for money than the current ones. (For me still is for soft reasons.. )

As cool as a Cox 09 is, it's a single speed engine. The OS FSR R/C engine is easy to start, idles well and performs perfectly for C/L Scale. I love this engine and it's Fuji, Tower, ASP, Magnum and other clones for the 3/4" to 1' size models.
Chris...

.....sold!