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Engine basics => Four strokes only => Topic started by: Andrew Borgogna on January 18, 2010, 01:48:07 PM
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I need some information, I am installing a Saito .30 four stroke on a RSM Ringmaster. The info I need is what would make for a good prop size and where do you locate the fuel feed from the tank relative to the engine? Also I am planning to use a uniflow tank and right now I am looking at using a 10x4 APC prop.
Andy
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http://stunthanger.com/smf/index.php?topic=14255.0
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I'm sure that Bob's link is best, but I hazard a guess that a 10-4 is just too low of a pitch for the Saito 30. That pitch would require rpm's in the 11-12krpm range (even before it unloads in the air), a bit too high for the Saito, IMHO.
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Andy - locate the tank right on the intake tube C/L. You may have to shim it a bit but not likely.
I have never had good results with a uniflow on the SAITO 30.
My best results were with a metal 2 ounce tank, Master Airscrew 9 1/2-6 and Brodak 10/23 fuel.
I do not recommend anything lower than a 6 pitch.
I just wire the carb wide open but there may be someone who makes a venturi for the 30.
When you run the 30 on it's side, you can try with and without muffler pressure. When inverted or upright, muffler pressure is pretty much a must.
Bob Z.
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Gday
I have a Saito 30 on a Ringmaster. I use a 10x6 tornado and a 3 oz Hayes clunk tank. Speed can be adjusted by setting the throttle. Mine is currently at 7/8's.
Cheers
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I just spent a lot of the '09 flying season playing with a pair of Saito .30's trying a lot of different combos on my PBY. Bob Reeves was a lot of help. On your Ringmaster, I would bet that an Evolution 10x7 prop and YS 15% nitro fuel all running at about 8500 RPM would work really well. I literally tried about every prop, tank and fuel combo you can think of and ended up finding that my main mistake was trying to run the .30's at to high RPM. Once I backed it down some and then loaded the engines with more prop it went much better. Save yourself some time, I would never have believed it until I tried it. y1
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Yep, a lot of difference between 2 strokes and 4 strokes. Bob Reeves put me onto the higher pitched props and my little 4S runs like a champ. Haven't even adjusted the carb intake. Set her on the rich side and fly.
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I recall that I had the shell of a 4-oz clunk tank on the inboard side of the fuselage, and a big balloon in it for the tank. I think I used a 9x7 prop. Setting the engine dead lean on the ground, it would go somewhat rich in level flight, but kick in in maneuvers when the speed fell off. I called it the 4-4 break (8-4 break, maybe?) The pattern took about 2 ounces of fuel, but I don't recall exactly what I was using.
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I recall that I had the shell of a 4-oz clunk tank on the inboard side of the fuselage, and a big balloon in it for the tank. I think I used a 9x7 prop. Setting the engine dead lean on the ground, it would go somewhat rich in level flight, but kick in in maneuvers when the speed fell off. I called it the 4-4 break (8-4 break, maybe?) The pattern took about 2 ounces of fuel, but I don't recall exactly what I was using.
Andy,
Try contacting Ray Firkins. He has a great combination on his Ringmaster.
Stan
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Thanks to all for your help and advice on this project.
Andy
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Well I finally flew the Ringmaster with the Saito .30 on it yesterday. The results were so-so. I was using a 10x6 master airscrew wood prop. I got the complete pattern in on the first flight but it seemed to be a bit light on the lines and demonstrated many of the problems outlined in other postings. The second flight I did the exact wrong thing and tried for more rev's, I got everything but the clover. Coming out of the first outside loop it just did not have enough power to climb up to the second one. Tried it twice with the same results.
After reviewing another thread I decided to try Bob Reeves method, took an 11x7 Xore prop I had for my Saito .40 and cut it down to 10x7 and reshaped the tips to match the original shape. I fired up the engine and set the revs at 8400 rpm and ran a tank through. Sometime this week I will give it a try only flying will tell. I will let you know how things are going.
One last thing, I did remove the Uniflo tank and replaced it with a standard clunk tank. Not having quite enough room on the outside of the plane I mounted the clunk tank on the inside of the plane. It didn't seem to make any difference yesterday, but I would be interested to hear any opinions on this setup from the experts. y1
Andy
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Inboard tank will be fine, hopfully you are running muffler pressure.
Be sure to get back to us with a flght report when you can...
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The Saito 30 actually runs very well on a 10 x 6 Cyclone
Randy
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Andy,
By cutting an 11" prop you end up with a "wide" blade prop, which most likely will load your engine more then the ideal.
Most of us try many props until we find the best one. In my experience with the OS 70 Ultimate I found out that it didn't have the juice to spin an Xoar/JXF 14x6 nor a Zinger Pro 14x6. But the TopFlite 14x6 with a narrower blade and less weight worked well. I am not sure if this is valid for all 4S, but I feel lighter props are better for 4S.
The TF 14 worked best until I found out about the JXF 14x6 for electric!
Please don't hate me for using an electric prop before getting one in your hands and compairing it's strength against a similar TopFlite Power Point for glow. The TF has a thinner section near the hub and is not as tough as the JXF-E. I started using this prop with confidence and my friends followed me. These E props are made with CNC and they have very accurate LE, airfoil shape and excellent pitch distribution. They are a lot more efficient, it just like getting more NITRO for free.
JXF/Xoar has 10x6 and 10x7 for electric, if you dare to try one S?P
Martin
edit: I am talking about JXF electric made of maple wood
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I have had at least eight different planes powered by the SAITO 30, from the Ringmaster up to the Cardinal ARF ~^.
I've tried just about every common prop from 9-5 up to 11-6.
9-5,6,7 & 8. (The Top Flite 9-8 wood was just too much - really overloaded the engine, the Power Prop and original Y&O were pathetic :()
9 1/2-6.
10-5 & 6.
11-5 & 6.
Older Top Flite and Power Prop wood, Tornado Nylon, modern wood in both wide and narrow blade configurations. APC and Master Airscrew plastic.
To date, the absolute best results have been with the APC and Master Airscrew 9 1/2-6. The performance is very close but if I had to choose one, I would take the APC.
Regarding tanks, I've been very pleased with my non-uniflow metal tanks but based on Bob Reeves excellent results, I plan to experiment with some plastic clunk tanks. I've just acquired two 2-ounce Du-Bro tanks.
Just my two cents.
Bob Z.
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No first hand expierence with OS four strokes but from what I have read on the forums I have come to the conclusion OS engines like to be ran a little faster than Saitos. Saitos like to be loaded (withen reason of course) and all the ones I'm running are happy in the lower 8K range.
Bob Z is the guy to listen to, am sure he has more time on 30's than anybody else in the world. I may have him beat on the 40 and 56 but not even close on the 30 y1
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Once again thanks guys. It seems that props make a big difference in this game. I will modify an APC and a Master airscrew black prop for tomorrows flying session. I will give each a try and see what the results are. Does this hobby ever get easy?
Andy
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Once again thanks guys. It seems that props make a big difference in this game. I will modify an APC and a Master airscrew black prop for tomorrows flying session. I will give each a try and see what the results are. Does this hobby ever get easy?
Andy
Once you get that 30 dialed in and running right it will get easy, the hard work is in getting there.
Of course, once you have a setup that works you then have to start seeing if it can be made better. In the fall you wake up and realize you spent all summer tinkering instead of practicing, your engine runs perfect but you can't fly worth a hoot LL~
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Bob R. ,
FWIW, most of the guys with OS 70 ultimate launch 8100~8300 rpms, but last NATS here I saw a great run of a Trivial Pursuit using the same prop I use but launching at 7400rpms, it was very hot, humid and very windy, it was one of the models I noticed handled the best in the wind, it was a very light model built from a good quality RSM kit.
Martin
oh and by the way, I have found later that the TF 14x6 I liked most in a very very hot day has a 7.4 pitch!
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Bob R. ,
FWIW, most of the guys with OS 70 ultimate launch 8100~8300 rpms, but last NATS here I saw a great run of a Trivial Pursuit using the same prop I use but launching at 7400rpms, it was very hot, humid and very windy, it was one of the models I noticed handled the best in the wind, it was a very light model built from a good quality RSM kit.
Martin
oh and by the way, I have found later that the TF 14x6 I liked most in a very very hot day has a 7.4 pitch!
Thanks for the info, as I said I have no first hand experience with any of the OS four strokes and should have left it alone.
Sounds like the OS 70 is allot like the larger Saitos, I am running Rev-Up 13-7.5's on my 56's but they typically measure around 7 pitch.
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Bob, Have you done any carb mods on the Saito 30 ? If so, could you share info? Thanks, BOB
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It's just like the 40, short version.... Make a new barrel out of aluminum, remove the needle assy by pressing it out and cut enough off the tip so it just sticks through the new barrel, Drill and tap the outside of the new barrel for a 10-32 nylon screw and put it back together with a little JB weld.
Posted a picture of a couple completed ones a few days ago in the Saito 72 thread..
http://stunthanger.com/smf/index.php?topic=15696.0