STG

My Feedback: (26)

What does better for fuel consumption in a pattern flying application? The 4 stokes or the 2 stokes?

It is my understanding that the 2 stokes are generally flown on lower nitro levels.

Thanks

STG

My Feedback: (26)

44 hits and only 6 votes? Should I add another category or do some not have good results to compare?

Please, if anyone has anything to add, please do.

The only real test I have seen is one done Bob Pastorello showing the 2 stoke a clear millage leader. http://www.rcaerobats.net/MotorCostComparison.htm

Thanks guys

J Lachowski

My Feedback: (46)

From what I have used and seen, the Webra 1.45/1.60 with mixture carb are among the most fuel efficient motors out there. I used to get two full Masters sequences out of a 16 oz tank. Can't get that with the stock OS 140 RX's I am running now.

STG

My Feedback: (26)

How far off would you guess the 140 RX to be off the Webra? Also, how long does it take to fly your sequence? I am just trying to get an idea on oz. min?

Thanks!

Divesplat

My Feedback: (7)

For all practical concerns, and it has been stated and debated a bunch, 2 strokes are the more economical choice.
Engines cost less
Maintenance is less with exception of bearings which need to be changed more, I've been told
Fuel is at a lower nitro level by tons
Fuel consumption is much lower

I should say that I love the YS DZ's though. We have called them the Harleys of the pattern engines. More expensive to run, repair, and purchase, but I just love that deep in the throat sound. Just my opinion.

However, if I was just starting out in pattern, for $$ reasons I would really really entertain the 2 stroke thought. A number of people have put the time in to have many of the earlier problems figured out now. the NSRCA list is a great resourse also for help.

Ed

rcpattern

My Feedback: (45)

I could fly the Masters pattern last year one time plus about 4 or 5 maneuvers on a 16oz tank with my OS 1.40. This year, I'm running a YS 1.60DZ in the same airplane, same tank, everything and my fuel consumption is almost exactly the same. I know that the Webra is really fuel efficient though. I love the extra power of the DZ though.

Arch Stafford

STG

My Feedback: (26)

I got a PM from someone who states that the 2 stroke 1.4RX is about 1/2 as good as the 4 stroke 1.4YS YZ for mileage.[X(]

MHester

My Feedback: (1)

Nevermind......................

-Mike

rcpattern

My Feedback: (45)

I certainly wouldnt go that far. I have about as many flights on my OS 1.40 as probably anyone. I would comfortably say I had over 1200 flights on them. I could fly 11-13 minutes depending on the sequence with a 16 oz tank. My 1.60DZ now is maybe a little better, but may 12-15 minutes top. I can't get through to complete masters sequences with either. If that was the case, he was obviously way too rich on the OS, which is very easy to do. The OS is definitely more user friendly. Fuel flip and fly, but make sure you put the Stainless bearings in it. The stock bearing will last about 30 flights, so if you get an OS, change them out to start. The YS motors tend to be more tempramental..but they are great motors and there is no denying the power. I think most people I know were about the same flight times with the OS. Around 12 minutes on 16oz.

Arch Stafford

Jeff-RCU

My Feedback: (4)

This is like comparing apples to pears. A four stroke is usually considered to be more fuel efficient than a two stroke of comparable displacement. A four stroke generally has a longer power stroke and doesn't blow raw fuel out the exhaust every revolution like a two stroke does. If you compare an OS91 2 stroke vs a OS 91 4 stroke, the 4 stroke gets much better fuel economy. The trouble is the 4 stroke has less power. Comparing the YS and OS are more difficult because the YS is effectively supercharged and run on 30% fuel, so it is packing more fuel per charge than naturally aspirated 4 stroke, bringing fuel economy down. There's a reason automobiles and big diesels are all four strokes, it's fuel economy and emissions.

MHester

My Feedback: (1)

I was getting between 17-20 mins on a 20 oz tank practicing advanced, but it dropped to about 16-17 when I started flying P-07. if this guy is getting 8 minutes out of an OS, he's either running a 6 ounce tank or has that needle WAYYYYYY too rich.

I had to retract my earlier knee-jerk response

-Mike

RC_Pattern_Flyer

My Feedback: (1)

My OS 160 with perry pump will allow me to fly 20 mins easily.

Chuck

Gregg G

My Feedback: (7)

The Webra is more fuel efficient. It only runs half the time!....

MHester

My Feedback: (1)

ROFL!!!!!

yeah, I haven't seen too much success out of the webras. they seem to be more hit and miss than the YSs. People either swear by them or swear at them.

-Mike

KeithB

My Feedback: (1)

I have a total of 624 flights on Webra 1.45 Motors. By and large they've performed very very well. The problems I've had have almost exclusively been with the bearings going bad. This was the only frustration I had with the motor as I would only get about 50 flights out of each bearing change. I've now switched to the stainless steel rear bearing and after 130 flights the bearing still feels great and the engine is still running awesome.

I've heard many people complain about the Webra's but inevitably when I'm at contests I have people impressed with my engine performance walk up and ask what engine I'm running. They're always surprised to hear I'm running the Webra.

I've helped numerous guys at contests get their Webra's running correctly, so it may just be an issue of knowing how to tune them.

I know the comments about the Webra in this thread are just for fun, but I thought I'd chime in since the Webras have been very good for me and I seriously believe I've had less down time than most of my 4-cycle and 2-cycle flying buddies that are using much more expensive engines.

As far as fuel consumption goes, I have a 19 oz tank and could easily fly 20 minutes or more (with minor variations depending on temperature). I've flown two Masters sequences and one Advanced sequence and landed with fuel left over.

NOTE: My experience is with the Webra 1.45 with the standard carburetor and not with the Webra 1.60.

Keith B

Troy Newman

I'll chime in here and take the hit everybody that knows better than I do.

I installed a 2oz header tank last year. The reason was I was curious if it would improve engine performance. I was curious if I could get a complete Prelim and complete finals pattern out of each tank of fuel. I was curious as I have seen Some of the European modelers using them...I was also curious if it would eliminate the sometimes burp I could see at the end of the a second pattern. This burp is not a good thing its a lean run and can hurt the motor any motor OS or YS alike. I always tried to restrain myself when it burped to get it down on the ground but sometimes I would push it. Not good on the motor.

So what I did was run my 20oz tank and just add a 2oz tank behind the firewall.

What I found:

Improved consistency on idle
Improved transistion and pickup after say a reverse avalanche
Improved flight times. I'm getting 16-17mins on my 20oz tank and its dry but the 2oz is still full when I land.

The result of this experiement was all good. The 20oz tank is dry when I land and the 2oz header is usually full. I think the 160DZ has so much power that you really don't need to use it all during the flight. The result is the motor is jsut limping along and as a result the fuel gulping is less. I'm flying a complete P-07 and F-07 sequence or mix and match some unknowns in there and can do it almost every single flight.
I think that a small header tank will help many engine installs including the OS and Webra motors. Does a motor need it nope not at all. Try it and you just might stick with it. Its pretty impressive.

Down side is the 3oz of weight the header tank takes to install it. I feel the downside is not an issue considering the benefits of the system.


My buddy flying the same model and same setup is only getting about 13-14mins on the same setup. He is using more power than I, and but he has the same benefits of the header tank.

So bottom line is I think if you manage the power you have it will manage your fuel consumption. A guy that goes on and off on the throttle will get way lower flight times than a guy that uses good management of his power. I have come to realize that many times I use way more power than needed for the job. The 160DZ allows a wide envelope of power. I feel this is an advantage at times.


Troy Newman

MHester

My Feedback: (1)

That doesn't sound out of whack Troy. Sounds reasonable.

But would you think an FZ getting almost twice the fuel "mileage" as an OS 140 is reasonable? Assuming same plane, same person, same pattern that is. THAT sounds out of whack. I know if you run an OS 140 rich, yeah it'll drink it. But if even close to properly tuned, I can't see an 8 minute flight unless it had an 8 ounce tank or so. That just sounds way way off to me.

-Mike

snap_roll

tho a 2stroke may consume less fuel, it may not produce the consistent punch on the uplines compared to a YS 4 stroke

CGRetired

My Feedback: (1)

Economy was my first choice when starting out in Pattern. I am Sportsman level and still practicing but my choice of engines may not have been the best, I chose the Evolution 100 and am still having problems with it. Archie Stafford has helped me and I still have not been able to see if his suggested fix will work because of the weather. It has turned cold here in NJ so not much flying is going on. Once the temp goes back over the 50 degree point, I will be back on the field and will see if the fix is in.

But, again, my choice of engines was due to economy. So far, when it has run right, I get three complete sportsman sequences in plus a few additional maneuvers and land. One problem I had was that the engine quit on landing. I thought it was out of fuel, but it was not so I would say that a 420cc tank gives me more than about 12 minutes of flying with that engine plane combination. (Excelleron 90).

You guys are talking way above my pay-grade here with expert and master level pattern and the 1.4's and 1.6 engines, but I do watch the more advanced guys (Ron and Dave Lockhart, Joe Zeigenfus, Rick Wallace, just to mention a few) and they all seem to get in at least two complete runs before landing, and I believe that Ron, for one, is running an OS 1.6. Not sure what Dave is running but he is FAI and he is one person that can squeeze that extra maneuver out of a tank where most of us would be sweating landing!!

DS.

tommy s

My Feedback: (55)

I have a question about a header tank for anyone who has used one. Does the small tank have a clunk
pickup or is the fuel inlet and outlet just at the stopper ?

tommy s

rcpattern

My Feedback: (45)

I will say I've been very happy with my new DZ as far as fuel economy goes. I've been a LIFELONG 2 stroke guy. My 2 new DZ's are the first YS's I've ever owned. Find a guy flying pattern for 8 or 9 years that can make that statement. I am absolutely in love with the power of the DZ. There is absolutely no comparison with the OS 1.40RX. I loved my OS's, but the patterns are so much easier to fly now. You don't have to anticipate the torque curve. You just move the throttle and it goes. The inside outside diamond 8 in Masters is so much easier now, as well as the veritcal 8. It is much easier to maintain a constant speed with the DZ. Fuel consumption is about equal to the OS, but it is so much easier to fly. It is the closest thing I've seen to flying electric. Very smooth torque curve. It took very little time to get comfortable with the DZ. I'm really looking forward to this year. The DZ has that extra little bit of oomph that will be VERY nice on hot windy days in Muncie in July. The one maneuver I've noticed it more than anything was playing with last years F-05. I didn't have a call sheet for F-07, but I already knew F-05, and the veritcal snap is TOTALLY different with the 4 stroke. It just powers out of it whereas the 2 stroke would mush out because of the pure lack or torque. For years, I have been one of the biggest supporters of the ease of the 2 strokes, but so far my experience with the DZ's have been nothing but great. I don't have a lot of flights on my pattern ship, but they have been very reliable on the UAV I work with at work. That is actually the reason I thought about switching was how successfuly we'd been with the DZ in that setup and how little fuel it was using.

Arch Stafford

dflynt

My Feedback: (48)

My header setup is one sixteen ounce fuel tank, and one four ounce header tank. Only the header tank has the foam DZ clunk. If I were to do it over, I would use a 16 ounce tank and a one or two ounce tank, but I am a lightness freak.

I have the same success with the header tank setup. It is the way to go. As long as you time your flights to not dip too far into the header tank, you will never have a dead stick or burp. And that is why you do not need a big header tank. The smaller, the better because your clunk will more likely be in complete contact with fuel.

I think the foam clunk gives you a little bit more ensurance against dead stick, but you could with a one ounce header tank, and 20 ounce tank use no clunk at all on the header tank.

The effect of a header tank is that of a single tank. It fills and drains exactly the same because it is connected as one system. The idea is to keep the header tank full.

David

lee101

with the header tank will the engine have enough back pressure to feed the main tank? or have to use uniflow?