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Author Topic: Holy criminy! What the heck?!?  (Read 3793 times)

Offline Mark Mc

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Holy criminy! What the heck?!?
« on: August 08, 2018, 04:08:17 AM »
As I don’t have a plane sized for the Saito 45 that I previously posted about, and I’m jonesing to fly a 4-stroke, I need something to put in the air.  I don’t have a 40-45 sized plane ready, but I do have a FliteRay with a .25 LA-S that was grounded because it developed a warp in the wing.  After fixing the wing I pulled out the scale, calculator, and ruler and cut back the nose & drilled new holes for a Magnum 30XLS that I picked up a few months ago. 

This afternoon I put the 30XLS on the test stand and pulled the rocker cover to set the valve lash and squirt some oil down the pushrod tubes.  This is what I found:







What the heck?  Nothing for it but to take the engine apart and clean it.  And boy did it need it.  There was gunk everywhere.  After a good cleaning it’s all oiled up and ready for a test run tomorrow morning.  Good compression and pulls through plenty smooth.  Hopefully it runs strong.  I’ll start with a Master Airscrew 10x6 and see how it goes.  I also have a 10x6 APC and 10x5 Master Airscrew and Xoar props to try and see what the engine likes.  If it runs good and my ankle heals by Friday morning, I’ll give this an air test.

Mark

Offline Fred Constantine

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Re: Holy criminy! What the heck?!?
« Reply #1 on: August 09, 2018, 02:29:52 PM »
The only time I've seen white crude like that was water contamination in oil, but that was not a model engine.  Could be though?

I also have an ASP/Magnum/Sanye FS.30, and I'm in the process of breaking it in for stunt.  First thing I noticed is that the needle valve leaks air horribly.  That means that the carburetor mods used for Saito engines won't work.    Keep us posted on your progress.

Fred
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Offline katana

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Re: Holy criminy! What the heck?!?
« Reply #2 on: August 09, 2018, 03:41:27 PM »
I know nothing about model 4 strokes but do suppose that they have no separate oil lubrication system - the oil in the fuel never getting anywhere near the valve gear. To me, the 'gunk' looks like lithium grease, put there for top end lubrication. Cleaning it out could do more damage than leaving it there!

Offline Mark Mc

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Re: Holy criminy! What the heck?!?
« Reply #3 on: August 09, 2018, 07:57:11 PM »
Well, after cleaning and running, it looks like it's happiest with the 10x5 props.  I can't really tell on the test stand which is better, the MA or the Xoar.  I guess flying will tell, if I'm good enough to notice a difference.  The 10x6 props just lug it down too much. This makes sense as the 10x6 is at the high end of the recommended props, whereas the 10x5 is upper middle on the prop chart.


I also have an ASP/Magnum/Sanye FS.30, and I'm in the process of breaking it in for stunt.  First thing I noticed is that the needle valve leaks air horribly.  That means that the carburetor mods used for Saito engines won't work.    Keep us posted on your progress.

Fred

Yeah, needling isn't that great.  It falls off rapidly as I lean it out, so it's going to stay about four clicks rich of peak for now.  It also does not like to start at full throttle, or hand start at all.  I'm pondering setups to start at half throttle and then lock in at full throttle before launch.  Air tests will be interesting.  It's certainly no Saito, and I'll keep a casual look out for a Saito .30 to replace this with.  I'm just not ready to shell out what they've been listing for lately.


I know nothing about model 4 strokes but do suppose that they have no separate oil lubrication system - the oil in the fuel never getting anywhere near the valve gear. To me, the 'gunk' looks like lithium grease, put there for top end lubrication. Cleaning it out could do more damage than leaving it there!

I was assuming it was lithium also.  But it certainly doesn't belong there.  I'm not exactly sure of the lubrication flow, but the rockers definitely do get their share of lubrication on these engines. My Saito .40 and .45 have plenty of residual oil in the rocker covers when I pull them after the few runs I made.  Maybe side mounting helps.  I didn't see it in my FA-40a manual, but the manual for the FA-40 states that it is preferable to side mount the engine.  Pulling the rocker cover occasionally and checking them for good oil is probably a good idea, but grease is never a good idea for these little monsters.  Least that's what I believe.  Maybe one of the four stroke gurus will chime in here.

Mark

Offline Robert Zambelli

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Re: Holy criminy! What the heck?!?
« Reply #4 on: August 10, 2018, 06:37:49 PM »
First off, the 4 stroke engines are very sensitive to air leaks around the carburetor/needle valve assembly. Any small leak will make needle valve adjusting a frustrating experience.
I've worked on a number of Magnum 4S engines and I was not impressed by the needle valve fits - most seemed very sloppy.

The lubrication on these engines is due mostly to piston blow-by. A bit will leak by the valve stems into the rocker chamber.

They also like a more than normal prop loading. I've run an 8 pitch on many - you really have to evaluate prop performance in the air.
The OS Surpass 26 (VERY similar to the Magnum 30) works well with a 9-6. The SAITO 30 does well with a 9-7 or 10-6.
BUT, don't be quick to judge on the test stand. Take a few different props to the field and see what works best in the air.

You might think about converting it to a standard C/L NVA. I've done a number of these and they work quite well.
Check with Dane Martin.

Bob Z.

Offline Dane Martin

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Re: Holy criminy! What the heck?!?
« Reply #5 on: August 10, 2018, 06:45:13 PM »
I've converted a few 30's for CL. The magnum is just like the OS black head version. Unlike Saito, they don't like tall props. Bob is spot on with the prop recommendation. All the prop playing with, I have found the black MA 9x6 is possibly the best. Now, that is experience with engines, I'm learning more being an engine expert doesn't make me a CL engine expert.
Lol . If you're trying to fly the pattern then start there. You may find yourself moving pitch, but I doubt you'll want to change diameter. The 10" made mine overheat every time. Saito can handle the taller props. I can check and see what venturi I started with if you'd like.

Offline Dane Martin

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Re: Holy criminy! What the heck?!?
« Reply #6 on: August 10, 2018, 07:10:46 PM »
I am gonna back peddle a little. The overheating issue I believe was a result of the muffler. I feel that the .20, .26 and .30 run better with no muffler. I know of a few people that successfully flew the 26's with a muffler, but I felt it resulted in a struggle for the engine here in the heat.

Offline Mark Mc

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Re: Holy criminy! What the heck?!?
« Reply #7 on: August 10, 2018, 08:50:16 PM »
Bob and Dane,

Thanks for the replies.  I'll try a couple of 9x6 props on this.  Dane, I was planning on using muffler pressure to an inboard mounted 2 ounce clunk tank for my FliteRay.  I'm pretty used to clunk tanks now.  How would one run without muffler other than going to a uniflow tank?

How does one convert to a standard CL NVA?  I don't think I've seen a conversion like that, just the Bob Reeves conversion.  This doesn't seem to like to start at full throttle.  Any suggestions on how I can get it to start reliably at full throttle?

Mark

edit:  Okay, I just found this entry - https://stunthanger.com/smf/four-strokes-only/surpass-fs-26/msg488537/#msg488537

It seems pretty easy.  I guess I can do that, although I'm still concerned at the full throttle thing.  I guess I'll just have to play with it.  Maybe the tight NVA with no air leaks will solve the problem.  Also, looking at the thread above I see that you're flying your Ringmaster on 52' lines.  What would you recommend for the FliteRay?  The same 52' lines?

Thanks, Mark

Offline Dane Martin

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Re: Holy criminy! What the heck?!?
« Reply #8 on: August 11, 2018, 12:02:05 AM »
Ok let me go from memory. The clear ringmaster has an os 26 fs. That was on 57-58' lines. The purple one only had a .20fs and that's on 52'. With your .30, basically set up the airplane as though you are running an FP 20. Start with 60' lines but you might end up in the 56+ foot range. Now aboutthe muffler itself, that was a decision from my own experiences. You may feel differently. The muffler is very small. So small, it may affect the venturi size you need to run. My suggestion would be to do the Bob Reeves carb mod.

Offline Dane Martin

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Re: Holy criminy! What the heck?!?
« Reply #9 on: August 11, 2018, 12:16:23 AM »
Edit

Offline Mark Mc

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Re: Holy criminy! What the heck?!?
« Reply #10 on: August 11, 2018, 02:32:56 AM »
Well, a little earlier I ran out to Home Depot before they closed and got some nylon spacers to do the standard NVA conversion.  But I chickened out when it came to cutting the carb manifold.  So instead I turned down one of the inserts to fit in place of the carb barrel, and then I cross-drilled a hole for the venturi.  The carb barrel slide bolt should be good to ensure that the insert doesn't rotate any.  I also shortened the spray bar a tad.  Now I just need to thread the insert for a nylon bolt and find a slightly thicker o-ring for the needle valve, and I'll give it another try.  If I can escape tomorrow from the wife, I'll head to Ace and get what I need to drill and tap the insert.

Mark

Offline Dane Martin

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Re: Holy criminy! What the heck?!?
« Reply #11 on: August 11, 2018, 10:57:54 AM »
If you have access to a lathe, the Reeves method is pretty easy. No need to modify the OEM carb at all. You just remove the throttle barrel and copy it using aluminium. Instead of the throttle arm though, you drill and tap that for the nylon bolt. I think I used 10-32. I'll check in a little bit.

PS, the guys who've had success with 4 strokes typically run muffler pressure. However, the guys who've been successful in contests have run Saito's. So don't be nervous to run muffler pressure to experiment.

Offline Mark Mc

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Re: Holy criminy! What the heck?!?
« Reply #12 on: August 11, 2018, 09:22:33 PM »
Unfortunately, Dane, I don’t have access to a lathe.  I’ve wanted my own mini-lathe for years, but the little amount of work I’d do on it doesn’t justify the expense of a good min-lathe.  I'll just have to do things by hand.  I turned down one spacer to replace the barrel and cross-drilled it for the venturi.  The local Ace only has nylon screws in 10-24, so I tapped one end of the spacer for a 10-24 screw.  On the other end I slid in another smaller spacer up to the venturi hole and profiled it to match the venturi edge. Then I drilled/beveled it to enclose the spray bar.  I pressed the new barrel into the carb body and lined up the venturi hole.  Next I drilled a small hole through the side of the spacer/barrel for the pin on the end of the carb barrel slide bolt to hold the new barrel in place.  I surfaced the side of the new barrel to be flush with the carb body, and then screwed in my nylon screw.  I didn't find a suitable o-ring at Ace, so I used a piece of fuel tube over the needle.  Seals quite well.  Voila!  Only time will tell how the spacers hold up, but for the cost of a 32 cent spacer, as 36 cent spacer, and a 46 cent nylon screw, I have a quick and dirty Reeves conversion for the Magnum 30 XLS.






I didn’t know what RPM to set the engine for initially, so I set it to 8500RPM using a Zinger 9x6 prop.  I have APC and Evo 9x6 props that I can try also.  It’s pretty steady, or at least it was for the three ounces of fuel that I ran through it.  I still can’t hand prop it, but I’m getting an idea of how to start it quickly.  Pull it through about four cycles with my finger over the intake, flip it through a few times briskly, then choke it for the first second that the electric starter spins the prop and the engine starts right up.  It runs much better than it did with the RC carb on it.


A very brief video of the engine running:



Not bad for $1.14 in parts and about four hours of work.

Mark
« Last Edit: August 11, 2018, 09:47:15 PM by Mark Mc »

Offline Dane Martin

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Re: Holy criminy! What the heck?!?
« Reply #13 on: August 11, 2018, 10:49:25 PM »
Looks great! To hand start it, try 4 choke flips then 6 fast flicks. Bring it up to compression and flip it backwards with a sharp slap. Should pop right off. But, anyway, excellent job. Let's see how it runs on your Skyray.

Offline Mark Mc

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Re: Holy criminy! What the heck?!?
« Reply #14 on: August 11, 2018, 11:12:48 PM »
Thanks, Dane.

Last question for the experienced builders and flyers.  Should I put a tripler on the inboard side of the fuse to help with vibration?  Or are ply doublers sufficient?

Mark

Offline Target

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Re: Holy criminy! What the heck?!?
« Reply #15 on: August 12, 2018, 11:30:47 AM »
Based on my Internet research, a tripler normally helps with stiffening the nose, which in turn helps with the engine run.

Glad you got the engine going. Did you use a drill press to fashion the plastic parts to size?
Regards,
Chris
AMA 5956

Offline Mark Mc

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Re: Holy criminy! What the heck?!?
« Reply #16 on: August 12, 2018, 05:12:43 PM »
Did you use a drill press to fashion the plastic parts to size?

Chris,

I did it the hard way, I used a sanding block, X-Acto knives, a Zona saw, a hand drill and drill index, and a caliper.  One other tool that I used, and is now becoming one of those tools I wonder how I ever got along without, is this $4.99 reamer:



http://www.valuehobby.com/accessories/tools-and-instruments/knife-edge-reamer.html

It still didn't take long, and the fit is very good.

Mark



Offline Fred Constantine

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Re: Holy criminy! What the heck?!?
« Reply #17 on: August 13, 2018, 05:41:39 PM »
As mentioned previously I am also working on a ASP/Magnum fs .30.  The venturi is super simple and made from plastic standoff material as done by others.  Machining is done with a drill press and a pre-WWII Sears lathe.  The standoff was drilled to match the intake manifold, and given a slight taper to a hand cut bell mouth.  It has no air leaks and the setting is fairly straight forward.  Spray bar is a Super Tigre copy that I had in the parts bin.  At 0.15 inch diameter it's probably to to large, but seems to work fine on the bench.

This morning I got in a couple of test hops. Take off RPM of 9400 with a 9x6 prop gives a steady rich run for the whole flight with only a little speed up at the end, and a clean cut-off.  I do need more level flight speed (5.45 laps  on 60' lines) and definitely need more break.  So I plan to ream out the venturi at the spray bar just a bit more.  An adjustment screw would speed up the process, but for now I'm all for KISS. Oh, I'm using a Hayes 3oz. tank on suction, no muffler, which could change at any time!

Keep sharing your progress.
Fred
Fred Constantine
Calistoga, CA   AMA 6798

Offline Dane Martin

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Re: Holy criminy! What the heck?!?
« Reply #18 on: August 13, 2018, 05:54:06 PM »
Very nice job. I've done that also. I think I recommend the Reeves method because no modification is done to the actual carb / intake.

Offline Mark Mc

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Re: Holy criminy! What the heck?!?
« Reply #19 on: August 13, 2018, 10:14:04 PM »
Fred, thanks for your update.  I guess 8500 RPM will be too slow.  I'll bring the RPM up to around 9500 RPM for the first flight.  Which 9x6 prop are you using? I have Zinger, APC, Evo, wood and plastic Master Airscrew, and one other that I can't remember. 

Mark

Offline Fred Constantine

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Re: Holy criminy! What the heck?!?
« Reply #20 on: August 13, 2018, 11:31:43 PM »
Mark - The 9x6 props were Zinger, B-Y&O, and APC.  Results were all fairly similar.  I happen to have a bunch of props in that general size and will do more careful selection when the carburetor trials are over.  This afternoon I reamed the venturi to .25 inch and kept the exit diameter to match the intake manifold.  The spray bar is .15 inch so it's easy to figure the effective throat area to be .012 sq. inches.  That's half the size of the .025 sq. in. stock carburetor not counting air leaks!   
Fred
« Last Edit: August 14, 2018, 11:26:09 PM by Fred Constantine »
Fred Constantine
Calistoga, CA   AMA 6798

Offline Mark Mc

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Re: Holy criminy! What the heck?!?
« Reply #21 on: September 08, 2018, 12:21:52 AM »
Well, I finally got to put this up in the air.  Mixed feelings about this one.  I understand now how everyone says you have to change your thinking on how to run an engine with four strokes.  I set it up for 8500 on the test stand, but I didn’t bother with that, due to the above comments.  I increased the RPM to about 9700 and I was getting just over five second laps on 58’ lines using the 9x6 wood Master Airscrew prop, and plastic clunk tank on muffler pressure.  One ounce was getting me just over three minutes of run time.  I like the lap time, but I did not like the line tension.  When pulling up into the wing-over it did not feel good, so I did not do more than a few mediocre wing overs today.  I’m going to do some more test stand work and try different combinations before I put this in the air again. 

One thing that may affect this is that I had to use an inboard tank, since for the four stroke I cut the nose back 1¼”.  Maybe if I try launching a couple of clicks lean it might richen up and give me what I want.  Unlike Fred, this one didn't cut off clean, it slowed down and limped for a couple of laps before cut off.  Maybe I'll kick out the front of the tank some more and see if that makes it cut off cleaner. 

A very short clip of the first test flight from my hatcam:




https://youtu.be/wU9G1r7Z2GY




Mark
« Last Edit: September 08, 2018, 03:56:10 PM by Mark Mc »

Offline Fred Constantine

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Re: Holy criminy! What the heck?!?
« Reply #22 on: September 08, 2018, 05:19:47 PM »
Mark – Good to see you got your Magnum .30 into the air.  The only thing I've learned so far is that the engine much prefers 15% nitro all synthetic over my usual 10-11-11.  OS type F and Enya #3 glow plugs both work well.  I tried a few flights without the muffler.  Using the finger on the engine after landing test it appears to run cooler. 

I've had to back away from engine work to sort out the airplane.  I made the classic mistake of putting a new (experimental) engine in a new airplane.  To sort the airplane I have mounted a reliable OS .25LA  with stock muffler.  The engines are interchangeable except for the fuel tank position.  Even the weight is very close. 

I plan some more bench runs.  I'll post the results if I learn something new.

Fred
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