I just got a new OS .65 AX I will be putting this on an old Sun fli 5. I have the Macs one piece black muffler for it as well. What props are you guys using on this engine, and how happy are you with this combo for classic pattern?

I have the .65AX in a GP Dirty Birdy ARF. I'm running the Macs Muffled Tuned Pipe. I'm very happy with the engine and it's performance on an APC 11x8. The Macs black mufflers are light, but add nothing to the performance. I think it would be fine with an 11x7.

Thanks for the info. I just wanted a reliable, user friendly powerplant. I have a tuned pipe, but not really interested in getting much more power. The reason I got the Macs pipe, is I like the fact it is one piece. Also, It looks better. I have had lots of experience with these mufflers. It depends on the engine as to whether they give a performance gain. They are not tuned though. It is just a matter of if they breath better than the original stock muffler. The old OS FP series is a good example. The Macs muffler really helps those engines out.
11-8 is the same prop my old Rossi .67 liked as well. It had a lot of power. Wish I still had that engine.

I've got an 61 fx in a fresh built Killer Kaos with tail dragger retracts @7lbs. I'm running a 12x6 MA with the stock muffler baffle removed. I know different engine but am curious what rpms you guys are getting on the ax with the prop sizes and exhaust set ups? I'm thinking of putting a tuned pipe or maybe a Jett type muffler, and trying different props to get a little more performance.

An idea might be to get rid of that MA... ;-)

I like the wood Falcon props as well as the Xoar's. Naturally, the APC's are also excellent.

Pipe it on an 11x7, 11x8 and you'll have an engine!

David

I loved my Killer Kaos. That was the one with the Rossi .67 I agree on the prop. Never liked MA. I mostly fly gas now and use Xoar almost exclusively. For my smaller engines I like APC. The bigger MA props flex so much, they are considered paint stirrers! I have had very good luck with the Jett Mufflers. You have to prop to them though. They have to be able to come on to the pipe. Generally I have found you have to down prop to get the RPM up high enough to come onto the pipe. That may be an 11-6, 11-7 for a .61

Anyone have any comparative RPM figures between the OS 65AX and the NR R61F Speed/13?

Robert, I believe that you were flying the 65AX on an APC 11x7 on your V2 if I'm not mistaken. What RPM was it turning piped on the 11x7?

TIA, David

David,
I was getting 15K with the 11x7, and 14,200 with the 11x8. 15% Cool Power fuel. 10cc Mac's Quite Pipe. Very thirsty. No engine mods.
BTW, it REALLY ripped on 30% heli fuel!
-Robert

Robert,

thanks - much appreciated. Were you burning about 1.6 oz/min or more than that?

The Speed/13 on an "un-tuned" stock NR pipe setup is clocking 13,500 on 10% Omega fuel (3 oz castor added) - APC 11x7. I figure that once tuned, on 15% fuel it could turn another 1000. So the difference between a modern RE 61 and SE 65 is about 500 rpm. Amazingly, the NR will turn on the same un-tuned 10% setup 14,500 on a Rev-Up 11x7.50 and 14,955 on a Rev-Up 11x7.25!

Lower inertial prop mass I suppose despite the slightly higher pitches...

These are my figures but others have done better; mostly on tuned setups though.

David

Wait till you tune the pipe! The NR will not disappoint.

I was burning about 17 oz. in 9 minutes, so more like 1.88 oz/minute.

Wood props typically show a lower pitch on the pitch gauge, especially as you progress toward the root, whereas the APC props are true across the blade. That may account for the higher RPM readings.

-Robert

We've been having problems with the back bearing cages blowing apart on the OS 65AX so keep an eye on them. It's happened to too many guys to assume they are being ran too hard. It could have also been a batch and not all of the engines.


Tim

I live near the coast, so corrosion is a big issue. I put some 440C stainless bearings (From Boca Bearing or R/C Bearings) in all of my engines and never look back.

-Robert

About the bearing issue.. I know not a 65ax but I have a 46ax that ate part of the rear bearing cage. Was running it on a macs pre-tuned pipe and 15% wildcat 18% synthetic oil. Propped with 11x7 and 11x8 ma @ 13,500 rich. Some with 11x6 ma @ 14,800 Upon disassembly I did notice the cage had corroded some, I probably forgot to run it dry once or twice but never ran it lean. Now It needs new bearings and a piston/liner. It's peeled and scored. I'll fix it with some Boca's stainless or ceramic? Are the ceramics rust resistant? I'm keeping and fixing it because it was a great engine and really fast on the pipe. Not to mention I can't get a Japan 46ax anymore.

I'm dying to try some different props on the 61fx Kaos. LHS doesn't have APC in 11x7 and 8. It's broke in now with 15 flights on it and seems to be running out of gear with the 6 inch pitch. Tried a 12x8 apc I had and was a dog way to bogged. Like 10200 on the ground and a slug in the air. MA 12x6 K is pulling about 12,000 on the ground with baffle removed and Wildcat 15. I'm loving the Killer Kaos though. Why did it take me so long to get/build a classic pattern plane? I'm watching this thread coz I've been eyeballing that Novarossi 13 engine too. That thing with the black engine and pipe slung down the side with the gear up would look so cool screaming by. :-)

Yep, loved my Killer Kaos. I will have to build another one day. I will do a better job on the stabilizer fastening the next time around! lol

What was your problem with it? I put some light glass on the center section of mine because I read it could flutter and break if the kit had light balsa in that area. Man that bluejay kit had the best balsa I've ever seen in a kit, light, clean and straight. If I bust mine or build another I'd like to move the horizontal tail forward to make it like a Super Kaos or Ultimate. Wonder how that would affect it's flight?

Throw some pics up of your Sun Fli. I love these old pattern planes.

Peace,
J

Here are some pics of mine. I've since tinted the canopy. Take no offense on the logos those are just put there for people who ask me where I got it? or ask me to harrier it or do a torq roll hehe. The one on the bottom is a rip off from a famous Tamiya model we all know, that fit my attitude in this hobby pretty close. ;-)

Peace,
J

Great looking Kaos. I am offended!!! lol Well, my stab seperated from the fuse one day. I flew that plane really hard for 3-4 years before that happened. My Sunfli is still not quite ready for public consumption. It has been bashed heavily. I used a foam core, and the span has been increased. This is just some parts set next to each other for the pic. The wing will actually be swept back. Now that I have an engine, I will be motivated to finish it.

None taken.
-Robert

Nice Robert.. :-) Nice to know I'm not the only one. That's one reason I built this Kaos. At the time I started it the Birdy and Phoniex ARF's hadn't came out yet. One of the reasons I'm glad classic pattern is came back There was the 40 Tower Kaos and I think the WM intruder. I like the pride and sense of accomplishment that comes with crafting my own little flying machine. Wish at least they'd come out with some RTC's. I'm wanting to build another probably the UFO. I'm just wood and film so far but the UFO would be a good one to glass, koverall, and paint. I'm like you though I really tried to source most of the stuff in the Kaos factory direct from US makers. Sorry for getting off topic.

Peace,
J

The one thing I do not like about the Kaos models are the Strip ailerons. Mine would always flex and gave poor aileron authority. My Killer Kaos was much better once I installed the servos in the wing, at the center point of the aileron. Here are some better pics of the Sun Fli, I mad the aileron mod to barn door style. This will perform much better. Brand new .65 AX setting up front. Should be great for this plane.