It's been many years since I flew with OS 2 stroke engines in old time pattern. Can someone tell me which engine in the 60-61 size is the correct one. I get confused with F FSR etc. I want the schneurle ported powerful one, not the lower powered one. Thanks. ( I want to put it in a Killer Kaos.)

Skip - This should be in the ballpark. OS 61 SF. The ringed version is more popular, you can usually pick a NIB for $175-$225 range, on auction somewhere, and maybe cheaper. The FSR should be good also, 3 piece case, I have not run any of the FSR.

The above is only my opinion, not saying it is right for everyone.

Crank

Skip, both the SF and the earlier FSR are Schneurle ported strong running engines. However, the SF is a long stroke designed to run under 12,000rpm with props like 12x8 or 11x10. It is happiest around 11,750ish. The FSR is an over-bore revver that is best suited to use 11x7 to 11x7.5 props spinning above 13,000. Both engines do well with pipes.

David

I owned and flew the .61 FSR and VF back in the late seventies/early eighties. They were both very nice engines and, yes, they were revvers.

My first time exposure to the SF series knocked my socks off. I couldn't believe the pulling power that that engine had while dragging around a fiberglassed and painted Super Kaos. Straight up was no problem whatsoever. This was while using the stock muffler too. When I recently bought some old engines for classic pattern models, I focused on obtaining OS .61 SF engines. Yes, I did pick up a few FSR and VF engines, but the SF engines are the bulk of the used engine purchases. I'm not willing to pay premium prices for NIB engines. Just one of my quirks, I suppose. I did buy quite a few groady looking engines that miraculously look fairly new once through the antifreeze bath. New rings from Mr. Bowman, new ball bearings from Mr. McIntosh at RC Bearings and a few miscellaneous parts from various other sources put me back in operation with reliable engines. I don't recommend my path to everyone, so buy NIB if that suits your shopping mode best.


Ed Cregger

THANKS TO ALL!!

You can also use the current-production .61FX engine. Comparable in power to the .61 FSR. Similar to the older engines, as far as power goes, is the .65 LA. An easy-handling engine if there ever was one. The .65 LA competes very favorably against the .61 SF as far as power is concerned.

I'm impressed at how well the FX apparently does with a pipe; this according to Mac's web site:

OS Max 61 FX Zinger 11 x 7 10mp 13,100 (open exhaust) 14,600 (pipe) 3.5"

Their site shows it turning slightly higher than the FSR:

http://www.macspro.com/tuning.asp

David

interesting.

That David Gierke sixty shoot out in MAN bore that out, too.

David

Right, interesting. If I thought that an OS 65 would pull around an almost 8 lb. well equipped Phoenix 6, I sure could have saved some dough. Did I read that right? Not to be controversial, but what kind of plane and weight of it, was tested with the OS 65 ?
Does it have the gut's of the OS SF's and FSR's ?

I am not an engine guru, and think that Bax has a good handle on the OS knowledge, but I am from Missouri on this one.

Crank

There was another OS engine back then that was popular called the Hanno Special, named after Pattern Ace Hanno Prettner. IIRC, it was one of OS first nickel plated cylinder models and there were reports of peeling even back then. It was a powerhouse engine designed from the SF for pattern. It was ported for tuned pipe use and won a lot of contests. rc-bearings

the only engine that i know of that the classic pattern forum guys here are trying to build a serial number data base on. probably the most discussed engine here.

With no tuned pipes allowed in SPA, it (Hanno) would be of little use in classic pattern flying. No, I'm not trying to tick you off, my friend(s).

What is or isn't classic pattern truly depends upon when one was born, I suppose.

I sincerely doubt that the .65 LA is tuned/timed similarly to the .61SF and is capable of pulling an 11/11 at the same rpm with the same consistency in throttling. Plus you must run lots of "extra" lubrication in order to keep the LA's bushings happy. No, I haven't tried it empiracally, so I could be wrong. But I doubt it.

I'm not trying to be disagreeable this morning. Sometimes I just wake up that way. <G>


Ed Cregger

I hear ya! I guess what engine you use depends on the rules. With Classic Pattern generally meaning the old FAI F3A rules, you would be limited to a .61 engine so the LA would be out. I also doube that the LA would come close to real world performance if an SF or FSR for very long if they are build any where near what the 40 and 46 LA models were!

Right - These OS 61SF's remind me of the old ST G60's we used to run. Lot of power. You are correct, .65 displacement vs. the 61 disp. limited to SPA. I guess everyone can be right about their engine choice, for whatever reason.
Crank

I hear ya! I guess what engine you use depends on the rules. With Classic Pattern generally meaning the old FAI F3A rules, you would be limited to a .61 engine so the LA would be out. I also doube that the LA would come close to real world performance if an SF or FSR for very long if they are build any where near what the 40 and 46 LA models were!
[/quote]

While not a legal powerplant for SPA...The Hanno is a great BPA engine!!

Most of the kits I have are not SPA legal...They are BPA airplanes...

Just my preference... [8D]

Chuck

The Hanno isn't really a BPA-type of engine. It was designed to turn an APC 12 x 12 prop at about 9,600 RPM when on the pipe. The pipe was required because that's how the engine was ported. The Hanno was designed for the early type of turnaround pattern that replaced the old ballistic pattern.

Ballistic-types needed a high-revving engine to enable the speed.

For late-60's-style pattern, then you might be able to do OK with a Hanno, but, again, the pipe is a necessity for the Hanno's performance.

If you want to compete in old-style pattern, then the O.S. .65 LA may not be an option, but if you're wanting to fly the older designs as they flew back then, then the .65 LA is a very viable choice. Keep a Kaos, Quik Fli, New Orleanian, Eyeball, and so on, all within their intended weight limits, and you'll have quite a nice-flying bird.

Thanks, Bax. I haven't been involved with Pattern since the Hanno was "New" so I am not really familiar with a lot of the new terminology.

Hey Bax,
What about the OS 55AX? SPA legal and more powerful than anything originally from that era, not to mention an effective muffler that doesn't seem to rob power. If you're just flying for fun (no SPA) than the 65LA is an excellent alternative.
-Will

Hallo Boys,

I`am in the process of aquiring a Matt Robbe Rubin and thinking of going to compete at the BPA event in Apopka this year at the Tangerine.
I`am absolutly new to these engines as i started flying rc in 1994 just the end of the era of the screaming 60`s,but man i love those!!!.

Anyway the question is"Is the latest YS long stroke 61 class engine(is it the YS61AR??) more powerfull than the OS 61 Hanno ringed version??,sorry if maybe this isn`t the right thread..!!.

Thanks for your help.

crankpin,
i recently purchased an os61 fsr which is my first os engine. i saw the pictures you posted and noticed that the crank vent hole has a screw closing it. the os i purchased had a vent tube on it. do i really need the vent tube? what does it do for the engine? i will greatly appreciate your input.

Bill,

it's hard for me to imagine any RE 2c 61 without a pipe. I suppose there are (were?) some mini-pipes of sorts that were essentially mufflers but without a pipe, a RE engine such as the Hanno is essentially a fireball spitter! I don't even want to think about about what would happen to the aircraft with a RE engine running without an exhaust system - not to mention the complaints from surrounding folk.

Maybe I've missed it over the years but aside from a pipe, is there any other option for a RE engine? (I actually recall that in the day the F1 guys used to run a thin straight header out the back of their K&B 6.5's. I actually have one of those but I might pass away before I run it... Unless you had ear protection, I remember that you had to be at least 50 yards away when those puppies were fired up!

David.

Sent you A PM

Crank

Hello Ed,

In this thread you mentioned that you gave your older and dirty engines an Antifreeze bath to clean them.
Could you explain to me what you mean with an antifreeze bath?
I have never heard of this, and it is always nice to learn something new.

I still have a few Webra 61 speed engines which could do with a cleaning up, and untill now I use paint remover paste to clean them.

Your way sounds better then mine.

Thanks,

Gert

Hi, sound-barrier.

I'm not the brightest light bulb in the pack these days. This subject has been covered previously on RCU probably one hundred times. Unfortunately, today is not a good day for thinking or seeing for me. Perhaps someone will list a search string for us that will point sound-barrier in the proper direction for looking up antifreeze engine baths here on RCU. I would greatly appreciate it. TIA


Ed Cregger