proptop

My Feedback: (8)

Just looking around and stumbled across this:

https://shop.graupner.de/webuerp/servlet/AA?wgr=9121

https://shop.graupner.de/webuerp/servlet/AA?wgr=9131

Looks like they're filling out their line w/ some new engines?
Graupner has them listed on their site...wonder when they will get over here?

Edited by moderator to remove link to competitive site.....

gkamysz

My Feedback: (19)

http://www.os-engines.co.jp/line_up/fsalpha56/index.htm

The english site hasn't been updated yet.

gkamysz

My Feedback: (19)

What do I see in the photos?

No crankcase breather. It is vented through the rocker box back into the intake port.

Big valves.

Baffled muffler.

Velocity stack.

w8ye

My Feedback: (16)

OS web site translated to english

http://translate.google.com/translat...ial%26hs%3DEiz

w8ye

My Feedback: (16)

30 grams heavier and 1 mm larger bore than the 52.

Says this is the new development trend for the OS four stroke line.

proptop

My Feedback: (8)

Thanks Jim...I wondered about that "competitive site" thing shortly after I posted...[X(]

It looks like I see machined grooves in the lifter bores to allow better lubrication up past them, up the pushrod tubes and over the rockers and valve stems? [8D] (about time somebody did that, actually)
Sort of a PCV system...

Looks like a YS/Saito-ish cast muffler...

I like the velocity stack...the whole engine looks pretty cool to me...wonder what Tower's price is gonna be?

Kweasel

My Feedback: (29)

OS has become superficial with their new designs. This new engine has no bronze valve guide/seats and no bushing at the top rod journal. OS has become very American, placing profit over classic engineering exellence. At this rate their next generation of engines will be just like K&B Sportsters.

proptop

My Feedback: (8)

Good eye! Didn't notice the lack of upper rod bushing, not a good thing...but then again, Saitos don't have bushings at either end.

Saito also did away with the bronze / brass valve seats/guides long ago...if O.S. chose their materials and processes well (?) it might not be a problem?

Guess time will tell if the customer has to be part of the R&D "team" aye!?

NM2K

My Feedback: (14)

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Notice that the wrist pin area of the connecting rod is not bushed. A step backwards?

The engine is terminally ugly. They should send their designer back to the clothing district and bring the engine designer back from Thunder Tiger.


Ed Cregger

Hobbsy

My Feedback: (102)

Ed, that would be a step forward since the bushing is not necessary.

NM2K

My Feedback: (14)

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***Grouchy response edited. My foot hurts!!!

If the connecting rod was made of high silicon material, like that used by Saito, why would OS have bushed the lower bearing?

In the "olden days" when synthetic oil became somewhat popular in club fuel, I began going through wrist pins in Fox and K&B engines like they were popcorn (every six months or so - and running them wet). The only difference was the lack of castor oil and upper wrist pin bushings. The engines with both ends bushed didn't appear to have a problem. K&B finally came out with the connecting rod bushed on both ends in their .40.

Glad to see you back posting regularly, my friend.



Ed Cregger

submikester

My Feedback: (6)

It is an interesting looking engine but it seems like a lot of work on how the engine "looks" and a questionable amount of work on the rest.

I'll let someone else field test it but my experience with OS engines has always been positive. Granted I only have one that is new (OS 70 SII) and the rest are older - in fact the youngest is probably 10 years old (46 SF ringed or 2x 61SF ringed). Since my experience has been positive I'm more inclined to reserver judgment.

NM2K

My Feedback: (14)

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Yes, very superficial indeed. If the connecting rod material was made of sufficiently high quality aluminum/silicon allow, there would have been no need to bush the lower/crankpin end of the rod. This does not bode well. So now we have an engine which MUST be ran on fuel containing some castor oil, unlike the older OS engines with rods bushed on both ends, which could burn fuel with straight synthetic oil. A step backwards, one might say.

It is sad to see this happening to OS, but it isn't anything new. I guess every country,company and philosophy has its day.

The majority of ARFs today are using inverted engine installations, where the engine is hidden. Yet, OS appears to be focusing their efforts on the new engine's aesthetics. This makes no sense, other than from the marketing folks perspective. The message is that it doesn't matter how long lasting the engine is, it is having the appearance to tickle the mind's of the morons that is important - even though the engine will be hidden inside of a cowl - where it cannot be seen. Never mind that it will not run reliably because of improper fuel tank placement of all ARFs being sold today.

If you were raised in the North East region of the United States, chances are you grew up eating a wonderful tasting breakfast meat called scrapple. Seriously, I love the taste of scrapple and especially the browned portions around the edges. One day I had the misfortune of learning the contents of scrapple. While I still eat it, when available (rare down South), I have to force myself not to think of the meat products contents, lest I gag. Our hobby has kind of become like that in some ways.

Oh, there were things wrong from the beginning. But my enthusiasm for the hobby easily permitted me to ignore those things. For instance, when I was a kid, what the hobbyshop owner said was gospel. You would never question the old folks. Everything sold at list price. Your access to different product lines was strictly a function of which distributor the LHS was connected to. Brands not included in the LHS' distributors line were considered "bad or evil". Seriously.

The trouble with growing older is that you don't swallow that tripe any longer. You know better. You have been around - perhaps too long - to swallow the notion that a hobbyshop owner knows anything outside of their shop. Most do not fly R/C any longer. Just ask them.

I guess I'll just keep collecting older engines and only buying something new from OS when something strikes my curiosity sufficiently hard. There, I've almost managed to forget about the unbushed connecting rod upper end - a true sign of less than premium engines - and I'm thinking of my older engines again.

Later.


Ed, NM2K

proptop

My Feedback: (8)

The main thing that struck me though is the machined passages in the lifter bores...
Bill Robison and I had a long talk on the phone one night (one of many ) and we discussed the oiling (or lack of same) of the upper end of model 4 strokes. We figured a way to do it, but it requires machining the lifters, and drilling / tapping and external plumbing, but this new way O.S. is doing it is all internal, and very clean in appearance. I think that will help in the wear rate of the valves/guides?

Maybe if the rod's upper end becomes a problem (out in the field) they will do a running change and mod the rod...(been done before...time will tell)

I agree with most of what you said Ed...except maybe the moron part...I kind of like the way it looks [sm=bananahead.gif][sm=spinnyeyes.gif]

gkamysz

My Feedback: (19)

The two ends of the rod are operating in two completely different lubrication situations. Hopefully they did their homework prior to release of the product. The materials have certainly changed over time. While milling heads for my diesel conversions I found that the older castings were soft and brittle. The Surpass II engines I did used much better material. The OS-FL70 must have been the test bed for the seatless/guideless heads. The PCV system is something they tried on the car versions of the engines. The FS26S-C and FS-40S-C have the slots in the lifter bores, but I don't know if they have the hole back into the intake port. I think it's a great idea. And OS is now plating all the steel internals so rust shouldn't be an issue. I think the look is a bit on the atrocious side, but I think that is coming from OS heavy involvement in the car market.

In the end, they have to do whatever they can to stay ahead of and maintain an image above the clone engines on the market that come at such low prices. I was expecting a new design shortly.

TimC

The O.S. .75 is now listed at Tower. Available in late June. Here is a photo and a few specs. $195

SPECS: Displacement: 0.75 cu in (12.3cc)
Bore: 1.02" (25.8mm)
Stroke: 0.93" (23.5mm)
Practical RPM:
Power Output:
Weight: 19.4 oz (550g)
Recommended Props: 14x6, 14x8, 15x7

tailskid

My Feedback: (34)

Anyone running the OS 75AX?

heli_Rod

I have an OS .55AX that performs great and just purchased an OS .75 AX for a scratch built FA-18 pusher prop jet project I'm working on. The .55 is a smooth running, easy to start power house, if that's any indication of how the .75 AX should run. I wish I had something hanging around just to try it out on and get it broke in. The .55AX is easy to start and easy to tune. I'm sure that I won't be dissapointed with the .75AX.

Rod

NM2K

My Feedback: (14)

I don't think that anyone can fault OS' attention to making easy handling engines. At least I can't.

I have a new .55 AX too. Gotta stick that sucker in a Kaos ARF and see what it is all about. I'm curious as to how it will stack up against the new Enya .61 CX. After that I want to see how both of these engines stack up to the old Enya .45 CX. The .45 CX is a tough one to beat.

Good luck with the .75 AX, not that you will need it.

Ed Cregger

alfredbmor

There is an interesting review related to the OS 75 AX by Andrew Coholic in the latest issue of FlyRc, it handles a 14 x 6 with no problem and so far than the tower engine of the same size can handle.
Good job on this one Andrew.
Sincerely:
Alfred.

Ken6PPC

I have never read a "review" in a magazine that was very critical of their advertiser's latest wonder. That makes ME wonder - why read them at all?