blw

My Feedback: (3)

I think the V Twin is the engine that scared Harley Davidson to the point where they lobbied for tariffs so they wouldn't go under.

Nothing wrong with a strong 2 stroke for acceleration thrills! The Kawasaki Mach 2 was king of the road for that kind of fun.

seanychen

My Feedback: (4)

I am by no means an engine expert, and I wish not to hijack the Saito 220 thread to discuss the fuel economy of over-bored engines. I just know that my Saito 220 lasts longer than my Saito 180 on the same 20 oz tank. My Saito 91 lasts longer than my Saito 82 on the same 10 oz. tank.

As for the propeller, I actually went to Toledo show 2 years ago to buy a Mejzlik 20x6, but it was sold out, and I bought a Biela 20x6 instead, not realizing there is that much difference between the 2 props. I don't want to spend another $50 for another 20x6. Do you think a MA Classic 20x6 is less loaded than Biela 20x6?

seanychen

My Feedback: (4)

Just to clarify, I was referring to the volume of air-fuel mixture above the piston when the piston is at the Top Dead Center. The combustion volume is merely the little volume that's trapped between the cylinder head and the piston's top surface when the piston is at the Top Dead Center. This is NOT displacement.

Displacement = bore * stroke. Displacement is the difference between the volume above the piston when the piston is at Top Dead Center MINUS the volume above the piston when the piston is at the Bottom Dead Center. I hope this can be understood without having to draw a picture.

Two engines with same displacement but different bore area can actually have different combustion volume. If this is still not understood/accepted, it needs to be discussed in a different thread.

Sport_Pilot

Hobbsey was completely correct. At high RPM the large bore short stroke will have more torque, this is because of better breathing of larger ports and reduced friction of the shorter stroke. At low speed the long stroke engine will have more torque, but this is because it is forced to use lower speed timing due to the smaller ports. For the long stroke there is also a slight mechanical advantage in that the piston and crank are close to right angles for a longer period of time. When both engines have the same displacement the force of the large bore on the short stroke will be the same as the long stroke and smaller area. That is more down force on a shorter stroke will have the same torque as slightly less force on a longer stroke. I suspect the maximum torque of each to be close, however that is dependent on so many things it may vary from one engine design to another.

closetguy

My Feedback: (13)

all of this talk about bore and stroke still doesn't make the saito 2.20 the stump puller like it should bee.i think the power of the saito is some where in between a os 160 and a moki 180. and the four strokes are suppose to be able to swing bigger props,the only good thing about the 2.20 is that it is light.
ENJOY!

Hobbsy

My Feedback: (102)

Sean, I mentioned above that I bought an APC 18x8W, I also received a Classic 20x6. I'll be back from my Son's next Friday and will run these plus an 18x10 JEN-C. CLGuy, the 18x0 should bring out the thumper in it if it has any.

Hugh, I apologise for calling you Brian in the PM, the notice I got said that skypilot responded to my post.

I'll be in a 757 200 in a bit.

seanychen

My Feedback: (4)

I think the title of this thread speaks of the bore on the carb, not the bore of the piston.

Hobbsy

My Feedback: (102)

Sean, I measured the carbs a while back and I think the stock carb bore is 10.25mm and the large is 11.5mm.

Flyer95

My Feedback: (1)

Anyone running a 19x8 prop to tell me the numbers?

closetguy

My Feedback: (13)

when the 2.20 was new only 3/4 gal through it i tried a PT MODELS 19-8 carbon i got 7700 on it. i am going back out later to fly and will try that prop again and make sure i was not miss reading it because the 20-6 Beila is a wider prop and 1 inch longer it was 8000 peak out.
ENJOY!

w8ye

My Feedback: (16)

Closet guy came out to the field around noon today and I measured his PT 19-8 at 7700 with my TNC tach.

However, the engine sounded and ran well. Seemed to fly pretty good to me.

onewasp

seanychen

Not a bad out, but tell me where the above quote refers to carb bore????

closetguy

My Feedback: (13)

Jim, BUT IT STILL DOESN'T HAVE ENOUGH POWER FOR ME
anybody want a nice looking book end for 300.00!
ENJOY!

seanychen

My Feedback: (4)

Not here

Some of us started diverging the main subject of carb design.

seanychen

My Feedback: (4)

I recall my APC 19x8W peaking at 8000 rpm.

seanychen

My Feedback: (4)

I tested the Master Airscrew Classic 20x6 today. It seems to peak at about 8000 rpm, with the main needle at 2 turns out from fully closed. The engine seems to be real happy with this prop, as opposed to the Biela 20x6, which struggles to reach 7500 rpm, and need the needle to be 3 turns out from fully closed.

The MA Classic 20x6 has great thrust too. The only draw back is its heavy weight, as I can notice a slight spool up delay.

For those of you who have good luck with Biela 20x6, I suspect that my carb is not getting enough fuel. I have a real simple fuel setup, with standard muffler pressure, on a profile plane. My fuel is 30% nitro heli fuel. I wonder if it could be the cause. What nitro are you guys using?

closetguy

My Feedback: (13)

seanychen,i use 30% in all saito's it's like (crack) to them, they just love it.
for me it's a toss up between the PT Models 19-8 and the Biela 20-6.
other guy's like the Mejzlik 20-6 they claim 8000 plus with it with strong pulling power.
i just hate to spend 50.00 on a mejzlik to find out, but the ones i have on my gasser's have always turn higher rpm's, seems like a extra 200-300. i also got the 2.20 on a profile and run a 16oz. tank on on side and a 4oz. on the other, like a header tank to try to get rid of any bubbles or other fuel problems. i use the stock muffler also. i will try the Master Air prop at lease it's a little cheaper.

Flyer95

My Feedback: (1)

I am very supprised seanychen liked the MA Classic.
I never liked the Master Airscrew Classic. Too much noise and not so good pull and it flexes a lot. They are made pretty for scale like airplanes. MenzS and APC are the good one I have tried on large fourstrokes.

closetguy

My Feedback: (13)

Flyer95,i hear what your saying and i have always heard the same about MAS props.
but trying to find a 19-8 or 20-6 whitch seems what the 2.20 likes there's just not that many to pick from.the plane does not fly bad at all with the 2.20,i just want it to be able to jump out of a hover when your down on the deck.
ENJOY!

Flyer95

My Feedback: (1)

There are many very good and cheap wooden props available in the US. I think Desert Aircraft has the MenzS. I use thick gloves when starting the engine on wooden props. On the stronger APC:s I use a homemade chicken stick which is just a 10" long and 1" in dia gasoline rubber tubing.

closetguy

My Feedback: (13)

you know i don't realy think that i will get the kind of performance that i want from the 2.20 by just finding the rite prop. 12-3/4 lbs. of plane is just to much for the 2.20. it would be more at home on a 10-11lb. plane.
ENJOY!

Flyer95

My Feedback: (1)

I would like to run my SA220 to see how she pulls because my SA180 is one hell of an engine and pulls 18LBS on a MenzS 18x6 and 10% nitro fuel.

onewasp

My 180 will pull a 13# plane vertical, to out of sight-----on take off.
Wildcat 15/18 all synthetic.
I think it accelerates all the way!!!!

closetguy

My Feedback: (13)

onewasp,i hear you, i got a 180 also with the same performance.thats why i shelled out big bucks for the 2.20.i thought it would make a rocket out of the 12-3/4 lb. plane and it's not that there is something wrong with the 2.20 i am getting the same rpm's as most other guy's.it does pull it vertical for as high as you can see,but it WILL NOT yank it out of a hover!it just kind of sets there for a few secounds and starts to to climb not something i like when you are doing tail touches.mabe i am expecting to much out of it? i got a moki 2.10 i might try before i put a mvvs 45 on it thats on the shelf also.
ENJOY!