Patriot

I heard the MVVS 1.60 gasser swings a 18x8 prop quite happily when broken in. My problem is that the plane I am building has only enough clearance for about a 16" prop.

I was thinking of using a 3-blade 16x8 by zinger.

Any comments on how the engine may perform with a 3-blader?

Patriot

GeraldRosebery

My Feedback: (14)

My advice is don't do it. These engines seem to prefer a two bladed prop. Try a 16 x 10 or 16 x 12

Patriot

I just hope that a 2 blade prop with the 10 or 12 pitch will work well enough give me the rpm/thrust I am looking for.

If multi-blade props are such a problem, as I have heard, then why are so many of them made, and when "can" they be used with real effectiveness?

Patriot

Daryl Martel

My Feedback: (3)

Graupner makes a very nice 3 blade nylon 15 X 8. It's the biggest 3 blade they make. I have 2 of them. Should work OK on that size engine. Lots of places carry Graupner but Hobby Lobby for sure...

NM2K

My Feedback: (14)

We can talk for hours about why model three blade props do not work as well as model two blade props, but experience is the best teacher. Buy one and try it. You may even decide that it serves your purpose well. Me, I don't use'em. BTDT

GeraldO

My Feedback: (2)

I tried a 16x8 Graupner "Super Nylon" three blader prop on mine. http://www.hobby-lobby.com/grprop.htm
I'm using the tuned MVVS exhaust. The Graupner prop flew the plane OK but it was slightly too much prop to let the engine get to full power "on the pipe". I could only get about 7600 RPM with it. It may not be the best three blade prop design out there though.

With a two blade APC 17x8 I got 8900-9000 RPM readings.

I haven't tach'ed it yet but so far I like the 17x10 APC the best with this engine/exhaust setup but I still plan to try others.

Which prop is best will depend some on your exhaust and which vintage your 160 is. Mine is the model that was out just before the current "Red Head".

Scoubidou

My Feedback: (17)

Hello Gerald,


With a two blade APC 17x8 I got 8900-9000 RPM readings.
1)Did you tach a 18x8 APC or 18x7 prop 2 blades?

2)Which tune pipe model did you use and what is your airplane model and weight please? I plan to use it on 24% CA Extra but that long tune pipe can bring dead weight!
Scoubidou

BigBird1

My Feedback: (4)

[B][QUOTE]Originally posted by Patriot1970
I heard the MVVS 1.60 gasser swings a 18x8 prop quite happily when broken in. My problem is that the plane I am building has only enough clearance for about a 16" prop.


Bigger wheels!!! Happens to me all the time...

Patriot

Sure, I could just use a couple giant Balloon Tires off my Neighbors' Quad ATV. Of course that might be a little too heavy then. Guess I'll need an even bigger Engine. LOL

No seriously, I haven't got the engine yet, but I think that is the one I will want to use, since I have heard good things about it. I think a 17x10 might work (maybe). I here the 17x10 works very well with this engine. I am almost sure an 18" might be a little too big. I could almost mow the grass with it.
Hey, I might be on to something.

Patriot

BigBird1

My Feedback: (4)

Oh I know...everyone is juicing up the front of their planes (me included) something has got to give...longer landing gears, blocking up the gear, bigger wheels...

I have two planes with big motors, one I had to block up the landing gear 2" and use 6" wheels to clear a 22" prop. The other one I just had to use 6" wheels...

The Sullivan Sky-Lite wheels do not weigh a lot..nore does the foam ones...

Kit manufactures are forgetting that when people put the max size engines, something is a lil' short...

BB1

GeraldO

My Feedback: (2)

I used the MVVS tuned exhaust designed for this engine. Morris Hobbies has it. It doesn't add "dead" weight, it adds a major power increase. The bigger problem is where do you hide that great long thing? On the Four-star it runs down the outside of the fuselage. I just tried the plane with a K&S "can" type smoke muffler last weekend. Still runs good but the power loss is quite noticable. It's in a Sig Four Star 120 which weighs in at about 13.5lb. Went from unlimited vertical with the tuned muffler, down to unable to hold a hover for more than a few seconds with the K&S. It does run a little smoother through the midrange though with the K&S.

I havn't measured the RPM or even ran it yet with an 18x8 APC but I have one and intend to try it soon. I bent the aluminum landing gear down farther on the Four Star to make it sit taller for the big props.

Scoubidou

My Feedback: (17)

Well, if it's so powerful, I w'ill try it.

We can hide the pipe under fuse by building a small cabane of balsa and monokote.
Did you weight your pipe? PLease let me know if you have the weight and dimensions.
Scou.

pe reivers

The MVVS tuned pipe is in resonance between 7000 and 9000 rpm.
Below 7000 the pipe falls off the edge slowly

PlaneKrazee

My Feedback: (14)

How does the MVVS engine perform with a conventional muffler on a APC prop?

Will it put out more power than a Saito 150 or Enya 155 with an in cowl muffler?

The Enya is a good, very fuel effecient engine that will run on 5-10% nitro and spin a APC 18X6W at about 8200 rich.

I wanted to go gas but the engines are taking a long time to come out and I don't think there will be any weight savings fuel/battery/ignition//batterymuffler vs. engine/fuel/onboard glow.

No room in my plane for a tuned pipe.

Scoubidou

My Feedback: (17)

I would not say the MVVS is better than Saito 150 glow. With the Bisson Pitt, we can get 500RPM more than supplied muffler.
Here are a few tach reading I have found on internet with a bisson pitt muffler:
APC RPM
16x10 8500
16x8 8200
17x8 7900
17x8 7960
17x8 8210
18x10 8050
17x8 8500
MVVS1.6
Engine 932.7g 32.9oz
Ignition 107.73g 3.8oz
Bisson pitt muffler 153.08g 5.4oz
motor mount needed ? 7-10 oz

A glow engine has better weight/thrust or H.P ratio than gas under 40CC. If you want to fly 3D, go with the Saito (lighter). If you want to fly a lot, at low cost and pratice IMAC or pattern, gas is the way to go. Gas engine in a 120 plane can fly well if the weight 10-12lbs max and is always heavier than glow engine.
I am in the same boat, no place for tune pipe but i will try to save weight for the MVVS
The 3W24 is probably the most powerful in that class but there are not many info available on the tach reading: it likes to turn 18x18 8000RPM and 18x10 7500RPM and very expensive motor for that size.
But How many Scott towel do you use to clean your plane with a glow!
Scou.

Patriot

OK, here goes. I am about to tick off some people and make others happy. But first of all let me say I have wayed all options and this is quite possibly the best decision for me.
I looked at the Saito 150 & Enya 155 initially for my next project. I looked at the weight of the engines and max horsepower output. They are both rated at 2.5 HP. Secondly, they both cost around $400.00 new w/shipping etc. And of course $16.00/gallon of fuel +accessories etc is pretty steep.
The new MVVS 1.60 Red Head costs the same, even a little cheaper than a new Enya. And, it's rated at 3.8 HP!!! WOW!!! And it runs on GAS!!! WOW!!!
Granted, it is a few ounces more, but I think well worth it. And with that much power, I don't see why it can't be made to drive the plane 3D as long as it is not a flying tank.
I don't know if 3.8 HP is accurate, but that is what they claim in the specs for the new Red Head design.
I talked to the guy at Morris Hobbies, and he said it would blow a Saito and Enya out of the sky in performance, but not quite as strong the O.S. 1.60 2-cycle glow.
I don't know, I could be wrong, but I think that the gasser in this class is the way to go.
I love Glow engines, don't get me wrong, but I do believe they are not the wave of the future for RC.
I can see in the near future, 4-cycle gassers replacing the glow 4-cycles as the gas technology is growing by leaps and bounds.
Even gas rotary engines are not too far off.

Just my penny's worth.

Patriot.

pe reivers

After a production lag late 2002, MVVS corrected some gas flow restrictions in the early 2003 production engines. The redhead came in April, and was a cosmethic change only. I must admit it is prettier that the colorless gloss anodize.
To get those 3.8 hp, you need all the tricks in the book, and the MVVS tuned pipe. It has been done, so the hp figure is legitimate.
3 hp @ 8200 rpm with APC 18x8N (personal measurement) is a better figure, because we tend to prop the engine way below the mazimum rpm, and get better performance out of the prop that way.
With a good high volume Pitts type muffler, the tuned pipe figures can be approached, with no more than 100-400 rpm loss. The exhaust volume must be at least 400cc.
Glow will always give a better performance in the same engine. The glow engine will also be lighter, less reliable, and you need a tank twice as large, so the 250 grams gained will be largely canceled out again.

PlaneKrazee

My Feedback: (14)

preivers,

Is that 8200 rpm with a standard muffler or tuned pipe with the 18X8N APC?

PlaneKrazee

My Feedback: (14)

I think the MVVS 160 is a good gas engine from what I have read but without the tuned pipe it will not have more power than an Enya 155 running 10% nitro. If someone could run a MVVS on a APC 18X6W we could compare.

I found the Enya's on sale at $80.00 less than a MVVS shipped. Add the cost of a pitts muffler, battery, ignition switch, fire extingisher etc., the cost of gas mix at about $4.00 a gallon compared to 10% nitro at $12.00 a gallon it would take a lot of flying to get a return on my investment. The MVVS may be worn out by then.

The Enya is supposed to be very fuel efficient, better than the Saito. The MVVS is using about the same volume of gas to make it's power.

I think I can use the same size tank with either and fly for about the same amount of time.

As for cleaning, I stick all of my exhausts 2" straight down from the bottom of the planes and 1/2 paper towel at the end of the day cleans them off, unless I'm doing a lot of tumbles, then I need two.

All of my glow engines have been very reliable, I run them 2-300 rpm rich.

Scoubidou

My Feedback: (17)

Well, i am glad to see that an MVVS specialist like Pé reivers is with us on that tread

As a professional engineer, i like to play with maths and unfortunately, all of us r/c modelers have tendencies to compare engines and performances without asking the real question!!
How many thrust do I need to fly my plane?

There are no bad engines on the market but only bad sizing for the airplane! Whatever if it's a Saito150, Enya155, OS160FX, MVVS1.6, we must check 2 things to select the right engine for a plane:
1) What's the require thrust to fly the engine (it depends of your flying style, aerobatics, pattern, 3D...)
2) What is the oz/sqft ratio of your plane?
In my case, i am building an Extra300l 73'' span. I want to try a gas engine for the first time but I will accept to lose some power because all glow engine have better weight/HP ratio than gas.
If I can build it at 10.5lbs instead of 11.5 lbs, i will have 28.5oz/sqft ratio and the MVVS1.6 can swing an APC18x10 at 7600RPM with a Bisson pitt muffler that gives me 18lbs static thrust and 1.7 thrust to weight ratio. This setup will be good for me to fly a lot, at low cost.
I dont know where you buy you 10% nitro fuel but in Canada, i pay 25$Can= 18$US/gallon.


Conclusion, keep your plane light and you'll enjoy!

PlaneKrazee

My Feedback: (14)

I Buy Byron fuel at my local hobby shop by the 4 gallon case.

Who says it will spin an APC18X10 at 7600 rpm?

How much is a gallon of gas in Canada?

pe reivers

Brian,
The 8200 was with the tuned pipe after rpm have settled. Similar results have been achieved with special homebuilt in-cowl mufflers.

Scou,
I too have seen many rpm figures on the internet, and it seems like I never can equal those rpm with ANY engine. I must be doing something wrong? Yet my engines perform as well, or better than my fellow fliers, and I often de-tune them for better all-over handling.
Or are those rpm figures like the speed we boasted for our tuned mopeds when we were much younger

PS
some serious test, done together with other IMHO trustworthy fliers all over the world obtained comparable results as I did, so continent influence can be neglected

PlaneKrazee

My Feedback: (14)

preivers,

It looks to me from what I have seen that if you use a Bisson muffler you will get 72-7400 with a APC 18X8W. This is what would fit in my install.

What is the fuel consumption at full throttle for the newest, most powerful engine? One oz. per minute?

Does 400 cc=400ml? That is a big in-cowl can.

pe reivers

cc=mL It stands for Cubic Centimetre

I measured the engine with a 15 Oz tank and Menz 18x8 prop, and got in excess of 20 minutes at full throttle (If memory serves me well)

PlaneKrazee

My Feedback: (14)

That is better fuel economy than I thought.