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OS 160fx with turbo muffler - 8/7/2002 6:50:20 PM   
lennyk


 

Posts: 565
Joined: 12/8/2001
From: Port of Spain, FL, USA
Status: offline 		hello,

Can you tell me what kind of realistic rpm benefits have been
seen with the turbo muffler on the 160fx ?

I am using apc 17x8 15% cool power and get about 9000rpm
with a bisson pitts

thanks,

L
       Post #: 1

TJ - 160 combo - 8/7/2002 10:57:48 PM   
bob27s



Posts: 4637
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline 		Hi, thanks for writing.

Actually the OS 160 is one of the biggest surprises we found with the Turbo Jett. It really loves the muffler, great broad range performance.

What we noticed is not so much a huge RPM increase, but the ability to turn larger props. Also keep in mind, that with this size engine and props, a few hundred RPM is a serious power increase.

Dubs test results are posted on his web site, and my expereice with the combination were about the same.. (basically variences due to temp/humidity/tach/user...etc).

http://www.jettengineering.com/accy/turbo.html

I have a Menz 20x7 prop turning around 7500 rpm (rich) using 10% nitro PowerMaster. This is about the same load as an APC 20x8.

Also, you can locate DaveN on here (look in other Jett post under SJ-76). He too runs this combination, and can provide you with his experience and performance numbers.

I hope this is helpful.

Bob Brassell

(in reply to lennyk)
       Post #: 2

OS 160fx with turbo muffler - 8/8/2002 12:02:39 AM   
lennyk


 

Posts: 565
Joined: 12/8/2001
From: Port of Spain, FL, USA
Status: offline 		thanks, you are correct also in that a few hundred rpm
increase for a larger prop would probably be a bigger overall
increase in performance than comparing the same rpm increase on a smaller prop size

(in reply to lennyk)
       Post #: 3

OS 160fx with turbo muffler - 8/8/2002 9:25:09 PM   
daven



Posts: 6646
Joined: 12/7/2001
From: Andover, MN, USA
Status: offline 		I run the same combination with a Pro Zinger 18x8 prop at about 9,000-9,300 depending on the weather. I have been very happy with this muffler.

I have a Mezlick 19x8 that I haven't tried yet, but hope to in the next week or so. I never thought I'd ever say that I had too many planes...

_____________________________

Dave Norman

klasskote.com
supertrc.com

(in reply to lennyk)
       Post #: 4

I need help with this combo, too. - 9/30/2002 2:41:40 AM   
Tyler-RCU


 

Posts: 52
Joined: 1/7/2002
From: Momence, IL, USA
Status: offline 		Hi guys,

I purchased the OS1.60 and Jett muffler over a year ago to install in a 1/4 scale cap. I have since sold the plane and decided to try bolting the power plant combo onto my Dave Patrick Ultimate in hopes of gaining more power than my YS 1.20FZ has been providing. The YS is simply not enough to torque roll train with.

Anyway, I started off with coolpower 15% fuel and a 20x8 prop. I think I was turning about 8600 rpm on the third tank of fuel on the ground. I ran the motor through the break in procedure as outlined in the manual. I then set the needles for optimum rpm (8600), and then richened the high end about 300 rpm slower. When I took off, the engine began coughing and loading up and died. The prop broke on an emergency, off field landing.

I then tried an APC 16x8 and was turning 9,600 on the ground. I didn't fly this prop because I thought it would over speed in the air.

I bought an 18x8-14 prop, but could only get it to spin up to 6200 rpm. I was afraid this would heat up the motor so decided not to fly with it.

Yesterday, I tried a mejzlick carbon 18x6, but found the thrust to be low, take offs sluggish, and vertical suffering. I think I was getting about 9,300 rpm with this prop. The engine sounded like it was predetonating in the air, and it would loose power after about 1 minute in the air. When I tried to richen it up slightly, the engine would then begin surging in flight with lots of smoke, and appear to load up before dying. Four dead stick landings in a row. I then swapped out the OS #8 plug for an Enya #3 and found I could run the engine slightly richer, which did seem to smooth things out slightly and delay the overheating in the air.

Off came the carbon prop, and on went an 18x6 wood prop. Thrust felt much better, slightly less rpm, and the plane flew much smoother, but the engine still predetonated and would loose power due to overheating. Three dead stick landings, then finally a decent flight with throttle management to prevent over-revving on the downlines.

Today, I couldn't make it to the field to fly, but I switched from 15% coolpower to 5% Omega fuel. I tached the engine at 8450 on the ground. I tried a 20x6-10 prop, but could only get the prop to produce 5400 rpm.

I spoke to another pilot on the other side of the country, and he informed me that there has been a tendency for the Jett muffler to cause the OS 1.60 to overheat in the air. This seems to be what I have been experiencing.

I have spent a small fortune on props and fuel this past week. I would greatly appreciate some advice and feedback on the perfect fuel/plug/prop combination.

I sure hope I can get this muffler to perform, because they ain't cheap! I have a demonstration show to perform on Oct. 12th, and I would like to have some time to get use to the new engine on this plane before flying in front of a large crowd of spectators. I am about ready to drop the reliable YS 1.20 back into and accept the lower power output.

I look forward to hearing some ideas,
Tyler

(in reply to lennyk)
       Post #: 5

OS 160fx with turbo muffler - 9/30/2002 4:56:51 AM   
daven



Posts: 6646
Joined: 12/7/2001
From: Andover, MN, USA
Status: offline 		My response above, was based on bench runs with the engine. On the bench, this combo seemed pretty awesome.

I did have a few good runs in the air on this engine/muffler, but I had some problems with the muffler holding together, and finally had to send it back to Dub for replacement.

About three weeks ago, I flew the engine, and had similar problems to what you are talking about Tyler. I'm not sure if pre-detonating is the problem, but even if I took off blubberly rich, it would go lean in the air and deadstick.

The engine seemed most happy with the Mezlick 19x8, but after about 5 minutes, it leaned out and went dead.

I had been running Omega 15%, but was planning on trying 10% Cool Power. I was also going to try flying the plane (Sig Extra 300 XS) without the cowl to make sure the engine is getting enough air over it.

Lastly, it has been suggested that I try a Perry Oscillating pump (Which I haven't tried yet).

I would also appreciate any info on this. I don't get a chance to fly this plane all that often, and I would like it to run the few times a year I take it to the field. I never suspected the engine/muffler, but now I'm concerned.

_____________________________

Dave Norman

klasskote.com
supertrc.com

(in reply to lennyk)
       Post #: 6

OS 160fx with turbo muffler - 9/30/2002 6:09:20 AM   
Tyler-RCU


 

Posts: 52
Joined: 1/7/2002
From: Momence, IL, USA
Status: offline 		I should mention that I do have the cowl off the plane, too. I wanted to be sure the engine was a keeper before cutting the cowl, as the cowl is already a perfect fit for the YS engine.

The baffling thing is that on the ground, the engine runs great. As soon as I take off, the trouble begins. I can run an entire tank through the engine without it overheating, surging, etc. when the plane is staked down with my plane holder. If I try to fly it rich, the engine is very unstable and surges in the air and always results with a deadstick landing. If I set it for smooth, consistant top end power, the engine heats up in the air and goes lean within one minute. Even trying to back off the throttle to cool things down doesn't seem to help at all.

I sent a copy of my post to Jett Engineering, and I hope they can walk me through this issue. I hear many people absolutely love the OS 160, and I hope my $100 muffler is not the root of our problems. I wonder if the Jett Team has actually flown this engine combo much or if their posted measurements are strictly from the bench, because my engine runs better on the bench than it does in the air.

I am new to these larger engines, so I am open to any and all suggestions.

Tyler

(in reply to lennyk)
       Post #: 7

OS 160fx with turbo muffler - 9/30/2002 5:26:38 PM   
bob27s



Posts: 4637
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline 		Hi Guys.......

Due to some other problems with the airplane it is in, I have only about 7 flights on my OS160/turbo combination. I too have it installed in a DP extra.

My bench runs were excellent. I had problems in the plane. If there is general problem with the engine/muffler combination and it is overheating in the airplane, it is probably going to overheat on the test stand too. I did not find this to be the case. If you think about this, it basically comes down to "what has changed?".

After running 6-7 different props and about 2 gallons on the test stand without any unexpected problems (ie it getting hot because I made it a tad too lean when I tried a 20x10 prop on it), and then encountering the problems in the aircraft, I did some analysis.

I also took into account cooling air provisions in the plane, noting that my cooling inlets and outlet were adequate for others running the OS160 with another type of muffler.

Three things I learned from the diagnostics

1) "standard" size fuel tubing is too small. I ran into some of the problems you mentioned, and most of it is indeed a problem with fuel system, and the engine kept trying to go lean in the air. You wouldn't think this would be a problem considering the fuel still has to pass through a needle valve, but apparently it caused problems in the fuel system to make the engine go lean. I solved this problem by using large fuel line, AND modifying the fuel tank to use 5/32" tubing and a large bore pick-up. Some folks have aso seen this problem with the OS91 as well, and used a similar solution.

In my case, the engine ran fine on the ground, and then leaned out 'slowly" over about 3-4 minutes. It was like the vent linke was plugged. I WAS able to duplicate this on the ground, after about 5-6 minutes. What is happening here is that the engine is trying to draw fuel, but for what ever reason "something" restricts the flow from the tank to the needle valve. It might be a standing wave in the tank pressure line, a hunk of junk stuck in the muffler pressure fitting, or something weird that limits tank pressure/vent.

I ensured that all passages were clean, made the large tubing switch, replaced the OS needle valve with the JETT one, and the engine now run an entire 24 oz tank, and holds the needle to the last drop (installed in the plane, on the ground).

2) As with any tuned exhaust, when the engine unloads in the air, it will want a bit more fuel. I found that backing off about 400 rpm from peak was about right to get good performance.

3) the JETT remote needle valve works a bit better than the stock OS needle assembly and held the setting better.

I have only had 2 flights since the retrofit. Had some structural problems with the airplane that have to be fixed. I guess I made the mistake of seeing just how much power the engine could deliver.

Anyway, I hope this helps with a few ideas.

(in reply to lennyk)
       Post #: 8

OS 160fx with turbo muffler - 10/3/2002 10:41:24 PM   
daven



Posts: 6646
Joined: 12/7/2001
From: Andover, MN, USA
Status: offline 		Bob,

Do you think the perry pump would essentially do the same thing as the larger fuel line?

I would think that if fuel draw is the issue, this would take care of it?

For me it would be easier to add the pump, rather than change my plumbing.

_____________________________

Dave Norman

klasskote.com
supertrc.com

(in reply to lennyk)
       Post #: 9

pump - 10/4/2002 12:34:45 AM   
bob27s



Posts: 4637
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline 		Hi Dave...

I would imagine the pump will not hurt... give it a shot. Just make sure when you order one that you get one capable of higher volume. My understanding is that the 'standard' perry P-30 is set up more for 40-60 size engines, and may not deliver enough fuel volume... and that a larger volume version is available.

Still, this issue is pretty perplexing. I spoke with Dub about it at length, and neither of us really understand the dynamics at work. If it runs ok on the ground, it should not become a problem in the air.

Standard fuel line is 3/32 ID, which provides a lot of fuel. You would think that would not make a difference.

Plus, the turbo-jett muffler creates a bunch more vent/tank pressure because of where the fitting is located...essentially like placing it at the fat part of a large tuned pipe (highest pressure).

The only other thing might be some very strange air flow within the cowling that prevents proper engine cooling. Maybe the shape and volume and location of the muffler all come into play. Hard quantify stuff like that.

Anyway.... let me know how things go with the pump

Bob

(in reply to lennyk)
       Post #: 10

OS 160fx with turbo muffler - 10/7/2002 7:59:33 PM   
daven



Posts: 6646
Joined: 12/7/2001
From: Andover, MN, USA
Status: offline 		I'll let you know about the pump, I'm just afraid I may not get a chance to try it out before winter.

_____________________________

Dave Norman

klasskote.com
supertrc.com

(in reply to lennyk)
       Post #: 11

Perry Pump - 11/12/2002 1:10:47 AM   
daven



Posts: 6646
Joined: 12/7/2001
From: Andover, MN, USA
Status: offline 		I got the pump installed and was able to fly it over the weekend. The pump has helped dramatically, and I am able to fly a whole flight without the engine going lean.

Unfortunately, I'm just not getting the RPMS out of the engine that I was getting when new.

I am now using a Pro Zinger 18x8 and turning about 8500, backed off to about 8100. This is barely enough thrust to sustain a hover on my Sig Extra 300xs.

My worry, is that I may have cooked this thing on one of the flights where the muffler came loose and it went lean in the air.

Any ideas Bob?

_____________________________

Dave Norman

klasskote.com
supertrc.com

(in reply to lennyk)
       Post #: 12

OS 160fx with turbo muffler - 11/12/2002 10:11:03 PM   
bob27s



Posts: 4637
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline 		Hi Dave...

glad to hear the pump worked out ok. It looks like the engine needs some serious fuel delivery for some reason, and it does not have a very good venturi-draw with the carb.

As for the lost RPMs... let it turn up for a little while. Put a small prop on it and run it for a bit. Up around 9500 rpm or so. Sometimes that will allow the fit to come back, and get back a few rpms.

Bob

(in reply to lennyk)
       Post #: 13

Pump - 11/14/2002 9:37:52 AM   
daven



Posts: 6646
Joined: 12/7/2001
From: Andover, MN, USA
Status: offline 		The pump is adjustable for fuel draw also. I will try and reduce the pressure a bit, and see if that helps bring the rpms back up. Probably be next year though.

Thanks,

_____________________________

Dave Norman

klasskote.com
supertrc.com

(in reply to lennyk)
       Post #: 14

OS 160fx with turbo muffler - 11/22/2002 12:36:41 PM   
krayzc-RCU



Posts: 5853
Joined: 3/26/2002
From: Kannapolis, NC, USA
Status: offline 		i picked up the jett muffler and 2-os-160 so and the vp-30 pumps so i will try these and see if i hav anything to add. talk with you al soon. ps one os-160 i will run the pitts muffer....

_____________________________

smooth as silk!

(in reply to lennyk)