RE: Everything Radial Engines
 

Hello John,

the plastic rocker boxes cary the rocker arm axles, I think, the small screw through the boxes are the axles, so You only could replace them by aluminium boxes.

Jens

RE: Everything Radial Engines
 

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Hi Tom

That might have been me commenting on quality! I have let fly a couple of times regarding the build quality of a certain Chinese radial... and I admit to being rather cynical about the ability of UMS-India to take on the manufacture of Seidel radials while maintaining the apparent quality of the German original. Not just accurate machining, that's the easy part with good machinery. The hard bit is the available metallurgy, heat treatment, chrome plating process, Quality Assurance system, etc etc. OS and Saito have been making engines for a long time in a country highly regarded for its engineering prowess. I have two Saitos, a 325R5 and a 200R3, and they are nice.

Since Horizon have taken on the UMS engines I am a LOT more interested. The gassers are very impressive. I like Pete B's low-key, non-pushy approach. It almost seems like he is quietly confident... I have read the excellent posts on your thread, tried to find bad comments, searched for YouTube videos and even rang the Australian distributor today for a chat. They got their first stock in last week. I have the opportunity to be the first Ozzie owner of an Evo 7-77, wouldn't that be good... it's a great looking engine.

Geez what am I saying, until last week I thought they were junk!

Regards RossG
radial1951
<br type="_moz" />

RE: Everything Radial Engines
 

Ross, Thanks for your comments. I have 4 of the 5 UMS engines, two saito90r3's and a 325 r5. The UMS radials are truly a joy to own and I am very critical of quality!! Let me know when you run one! -Tom

RE: Everything Radial Engines
 

http://www.ebay.com/itm/SAITO-5-Cyli...item3a71099f46


Why is my definition of "BRAND NEW" so different than these ebayers?

If it's been mounted, on a test stand, had a prop bolted to it, started, ran , and broken in , then it's no longer Brand New, NIB, or even New. It's now a used engine.

Actually it was a used engine from the moment you bought it from the retailer but I give ya that if it hasn’t had a prop bolted to it, been mounted on a plane or test stand, and never has seen fuel.

RE: Everything Radial Engines
 

Also notice the blue liner is from an OS 5 cylinder engine.

RE: Everything Radial Engines
 

Saw this on ebay. It's neat but I can't afford a $600 desk top model.

http://www.ebay.com/itm/Radial-Aero-...item27c417a69d

RE: Everything Radial Engines
 

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Because they are SELLING and you are BUYING :-)

Actually it looks like quite an old 325R5. The rocker covers appearto be CHROME, unlike the later model with GOLD covers. That explains why I can't see the front glow plug i.e. the earlier ones are single plug heads. The box is also a dead giveaway. My 325 is 2 years old and came in a lovely white box with GOLD embossed SAITO logo etc. with a white hard foam/sponge insert to cradle the engine, tools, flexible stainless steel exhausts etc. I wonder just how long it has been sitting around...

Buyer beware!

Regards, RossG
radial1951<br type="_moz" />

RE: Everything Radial Engines
 

Someone will answer this question........I have a evo/ums7-77 which has a Xoar 24x10 wood prop. This was used for running the engine in and a couple of test flights.
However I would like to gain more revs at WOT (currently 5000) and more thrust for take off.
Would a finer pitch help?? Or do I need to reduce the diameter aswell. How about a 22x10??

Thanks

RE: Everything Radial Engines
 

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Hi cymaz,

Well your question has been here a while and no takers? I haven't run my EVO77 yet, but here's a couple of ideas. They may not be perfectly correct, but ...

As I understand it, the PITCH will determine the speed you can do at a given rpm, AND how fast you will get there. A bit like gears in a car. A low gear (pitch) will allow fast acceleration (thrust), but you'll run out of revs fast, too. Prop DIAMETER will load or unload the engine at a given rpm.A change in a car's final drive ratio or wheel diameter (prop dia) will change engine revs at any given speed. This may allow your engine to operate in its optimum rev range at the desired vehicle speed. A bit like using overdrive for high speed cruising.

OK, IMHO, going to a 22x10will unload the engine, lifting the revs into possibly a better power range. This MAY allow more SPEED AND ACCELERATION (?) if the engine is now producing more POWER due to the increase in rpm from not having to swing such a large prop.

Going to a 24x8 may do only a little, other than more noise (engine and prop rpm) and MORE REVS for the SAME SPEED.Again, this may lift the revs into a better power range, allowing faster acceleration for takeoff.

Luckily, you have a benchmark at 5000rpm with a 24x10. If you want to go faster, I say try the 22x10. Same pitch speed, more revs = more speed. ButONLY if there is enough POWER to actually do it. If there is, you may find the plane will also accelerate faster.

If you just want the takeoff acceleration and vertical performanceon those huge loops, then a24x8 is more likely the answer.

Like I said, "As I understand it..." I would really like to read more comments on this topic. Especially if it involves actual flight or test data with these engines.

Interesting point, in the test report for my EVO77, the factory (supposedly?) used a Menz 24x8 to achieve 5550rpm(for 20 minutes!)... another benchmark (?). Ok, I'm a bit dubious... I do hope I'm wrong. (I plan to take the back off the engine in a few weeks for a look inside.)

Regards, RossG
radial1951
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RE: Everything Radial Engines
 

Radial,
Thanks for the reply and the theory, great reading. Having now flown the engine 6 times there seems to be a happy medium of 24x10. I have my 777 on a plane of 11KG.

The pull is quite powerful and provides serious take off speed. Up in the air the plane will be happy at 1/2 throttle.

The plane needs 1/4- 1/3 throttle on landing approach as the prop if too slow does act like a large brake!!

Hope you find the info useful for your flying

RE: Everything Radial Engines
 

*Hi cymaz

Ah, the big crop duster. That's just the sort of info needed for the EVO777 radial. Funny about the "happy medium", that's the recommended prop for the engine!

Interesting point about the prop being a brake. Maybe the extra friction of a radial means it goes to idle when you shut the throttle. Like, NOW. The breeze can't drive the engine via the prop, so the plane stops! I didn't really figure it out until now, but I lost my Yak 50 (9kg, Saito 325R5) on it's maiden landing last year when it fell out of the sky just before the runway. I pulled it back to idle, expecting to glide in. But it slowed right down, dropped a wing, and that was the end of that. I was stunned. Live and learn... good point.

Regards, RossG
radial1951
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RE: Everything Radial Engines
 

RossG

Big crop duster,take a look, 96" span
[link=http://www.bing.com/images/search?q=general+western+meteor&view=detail&id=0E5 35E30F134932911462A37B0547FB8E860F646&first=0&FORM =IDFRIR]here[/link]

RE: Everything Radial Engines
 

CYMAZ Very nice ride!

RE: Everything Radial Engines
 

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Hi cymaz,

Yes, I've been watching progress over on the UMS-Evo Radial Forum. It's a great looking plane, full of character.

How cool is it to have a totally unique scale aircraft. Not likely to bump into another one at the local field!

Very nice job, too. It would be good to SEE &amp; HEAR a flight video... :-)

Regards, RossG
radial1951
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RE: Everything Radial Engines
 

Glad you approve, thanks. Try this [link=http://www.youtube.com/my_videos_edit?ns=1&video_id=FBnhp7x3WWQ]link[/link]

RE: Everything Radial Engines
 

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cymaz, that doesn't work...

EDIT : Do you mean THIS ONE?

Regards, RossG
radial1951
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RE: Everything Radial Engines
 

OHHH YEAHH:D

RE: Everything Radial Engines
 

Thoughts on the best radial for the new EMS Sea Fury 80"? I can't find the cowl diameter posted but the specs call for 30-40cc gas engine. I'm assuming this means 2 stroke single cylinder. I would think 50-60cc radial would really make this plane scream! (as it should!)

Any ideas?<br type="_moz" />

RE: Everything Radial Engines
 

Some Radial Eye Candy.....

RE: Everything Radial Engines
 

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Ha! The Fort Knox of Radial Engines!

But there's one missing. A Twin Plug 325R5. But having the world's only Saito 750R5 almostmakes up for the omission... ;-)

Nice collection, Steve.

Regards, RossG
radial1951
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RE: Everything Radial Engines
 

So very true. The Keleo/Saito 750 has dual plugs.. :D

It'll have to do until I find a nice 325.

RE: Everything Radial Engines
 

Hi stevesak,Hi Radial1951,I have a 325RD,and a 450RD,SO LET ME GET THIS STRAIGHT, if I duck out to the shed,pull the two radials apart.buy two more 450 cylinders,throw all the old 325 cylinders away,graft the 450 cylinders onto the 325 case,I'll have the 2nd 750RD !!! Maybe I can pull the heat sinks off the 450,whack on another three cylinders and have the worlds only 900RD6.won't Saito be surprised !! On a more serious note,how did you get your hands on this engine,did you build it or is it a one off Saito? Cheers,Mark.

RE: Everything Radial Engines
 

Do I need to put a pump on a Saito FA-200R3? I am mounting it up for the first runs now. The Perry site says pumps not needed for opposed twins but no mention of radials.

RE: Everything Radial Engines
 

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Hi stevehookem,

Here's my 200R3 mounted in an Su-31. There is certainly no need for a pump or even to pressurise the tank from the fitting on the exhaust. Just run the tank vent down with the exhaust pipes, you will see the overflow when the tank is full, also run a tube from the crankcase drain. The whole lot is tied together and just pokes out a hole in the bottom of the cowl.

I also have a tube from the priming nipple on the carb to a fuel dot on the Right Hand side of the fuse. A squirt of fuel while giving it a few flips, turn the glow on, and she's usually (?) off and running in a few more flips...

Here's the taxi tests: http://www.youtube.com/watch?v=-XsYDOnwnk8

Regards, RossG
radial1951
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RE: Everything Radial Engines
 

WOW steve, thats some collection you got there, whats your favorite?