3w 42i
 

I have run a full gallon of fuel on this engine and so far i can't get any higher than 6300 rpm on a Master Airscrew 20x10, so far I'm very disappointed with the performance of this engine, the other guys say that they can get up to 7400 rpm on similar size props.
Does it have to do with the running in period? does it need to be longer or does it have to do with the prop brand?
Any help is welcomed

3w-42
 

I have a 3w-42 and right out of the box I was getting 6800 on a Mejzlik (Still can't spell it) 20x10.
That Classic prop of yours is good for Warbirds scale looks but does not do well with my 3w's.
I have about 2 gallons through the 3w-42 and it has increased to 7000. Let it run at least 5 gallons through it and also go for a different prop for a while.

http://pages.prodigy.net/gcleveland_grsmodels/

The above is an address for GRS... they make a little narrower prop that look exactly like Mejzliks, just cheaper. They are in the Southern USA.

I use their 20x10 to break my engine in then switch back.

Good Luck
Hal

3w 42i
 

I don't have experience with that particular engine,but I can tell you that MA prop is terrible.Get a Menz,Mejzlik,APC or even a Pro Zinger,and I'll bet you'll see a majior improvement.Heck if you have to,go outside and cut one out of a tree branch,you'll probablly be better off!! JJ,LOL.
I think APC quit making large props,but I think I have one I'll give you if you want to pay the shipping.
Mike

3w 42i
 

thanks Hal
I will change the prop and see if there is an improvement, and i can feel that the engine is getting better.
Hal in what plane do you have the 3w? how heavy?
i have it on a 1/4 sukoi that weighs about 16 pounds and is very marginal.

3w 42i
 

Mike
how much do you want for the prop, and what size is it?

Thanks
Tiago

3w 42i
 

The master Airscrew 20 X10 has a lot of mass to turn. I have a new BME 44 and I started with a Master Airscrew 20 X 10 also. I could only get 6400 RPM on the first tank. I took that prop of and tried a Top Flite Powerpoint 20 X 8 and it went up to 7000 RPM. I am going to try a Menz or a Master Airscrew Scimitar which looks like a Menz. Were you using the Scimitar prop or standard Master Airscrew? Your engine should get stronger as you burn more gas. I don't have much gas through mine yet, but that is what everyone is telling me.

Good Luck,

Chris

3w 42i
 

Tiago,I must have given away the APC 20X10,I do have a Zinger 22X12,and a 22X8-14,and a APC 18X10,If you want any of them,let me know,just pay $5.00 for shipping and you can have it.

Props
 

Chris is absolutely right. Start with smaller prop. I have an engine that says use a 26x10 but that is too much prop and I am breaking in the engine with a 24x10.
I have put the 3w-42 on a 1/4 Lanier CAP ARF. It has 80.5 inch wingspan and came in at 16 pounds. It pulls the CAP around with authority. I have not gotten too much gas through it before an accident with the ground. It came up and "Smacked" the plane. I have it 80% rebuilt and doing it better this time. The engine being rear carb was not done well to start with, I am fixing that.

I am also switching to the new 3w clear oil additive that Cactus Aviation has introduced. Less black stuff on bottom of plane. I used High Quality Honda Racing oil.

The 3w with 24x10 prop is a 3w-85B2 on Hangar9 CAP arf. Fabulous plane!! Hmm see my pics in member picture section.

Good Luck,
hal
[email protected]

3w 42i
 

Mike
Thanks for the props but i don't think that does sizes well help.

3w 42i
 

Chris
I'm using the Master Airscrew normal. Do you know what are the benefits of using a carbon fiber prop? someone told me that because they are lighter you should use one size up, e.g. from a 20x10 to 21x10. is that true?

3w 42i
 

I have that engine and can tell you that you should be patient with the break in.

Mine turns a Menz S 20x10 @6900
Menz ultra 20x10 @ 7400

The MA are not for this kind of engines.


epc

3w 42i
 

epc
have you tried to use a Menz 22x8? how did it perform by comparison to the 20x10 and what rpm did you get?

Tiago

3w 42i
 

No but I have a mejzlik 22x8 that will try later and let you know.

epc.

3w 42i
 

MY bme 44 is still pretty new. A carbon fiber prop is lighter but they are also thinner. Look at an APC prop. They are thin at the tips therefore the engine can true a faster RPM. I am going to switch to a MA scimitar 20X8 or menz 20X8. My hobbyshop has the scimitar so I will probably try that first.

Chris

fuel tank
 

hi guys thanks a lot for the help so far the engine is running better the more I fly it and pick up another 300 rpm still with the old sh*@% MA prop . But know I have two other problems: 1st the carb sprays quiet a bit of oil inside the plane, what can I do to solve that? and 2nd I can't get more than 13 ~ 15 minutes with my 24 oz fuel tank (already got 2 dead sticks, run out of fuel) is that normal? what size tank should i put in?

Tiago

3w 42i
 

A reed valve engine that lets any fuel at all come back out has a leaky reed valve.....

3w 42i
 

TD -1

Is the MAS 20 X 10 prop you are running a wood prop or composite prop? I find that the MAS wood are very poor props and turn 1000 rpms slower than the MAS composite props.

My 3w-42's (2 of them) turn in the mid 7k rpms with MAS composite 20 x 10 props

It has been my experience with 3w engines that the cc displacement is a good measure of the fuel consumption per minute in cc with the throttle wide open. Since there are 30 cc to an oz, fuel consumption at full bore is 1.4 oz per min.

All of my rear carb 3W engines spit fuel out the carb. (15 3w-24s, 2 3w-42s, 2 3w-50s
It is a problem with 2 stroke engines but it is most obvious when the carb is enclosed.

Elson

3w 42i
 

rc bugman
I was using a MAS 20x10 wood prop and managed to get up to 6500 rpm with that prop. Regarding the fuel that cames out of the carb, there must be something that can be done, i spoke with the local 3W agent and He told me that there wasn't enough air getting in the airframe and the engine was running rich that i had to make wools at the back of the fuse, others told me to build a box around the carb and make a 50mm tube to bread air from underneath the fuse. I haven't tried any of this options so far but the inside of the plane (receiver, servos, batteries) are getting very oily. Elson do you just leave has it his ore have you done something about it?


Tiago

3w 42i
 

TD-1

Change your prop to any other brand including the MAS 20x10 composite and your RPMs will increase 1000 rpms. That prop is a terrible prop.

The 42 seems the worst engine in the 3w line for spiting fuel. I have plenty of air going to the carb, I have leaned the mixture to max performance (7500 rpms) and it still spits fuel. The engine runs great and works very hard pulling a plane with an insect net attached through the air for 30 min at a time. I finally just installed a shield between the engine and the rest of the stuff in the forward fuse.

I would purchase another prop and install it before you try to lean the engine and reduce the fuel spitting. With the very heavy engine load that prop produces you may be also running very rich

Elson

3w 42i
 

Elson
Thanks for your help, i will do that.

Tiago

Hi,
Sorry to bring this thread up again after so many years. I do have two 3W 42i engines (still brand new!) and was thinking to use them for the 33% W.Hostetler Piper TriPacer. From experience would you think that the engine would adequately be able to pull this plane around the sky? No aerobatics are envisaged.
Any help will be appreciated.
Thanks

Reuben

Hi,

A 3W-42 would have plenty of power for scale type flight for a 33% Tri pacer if the all up wt is not too heavy. Prop choice is important. I would start with a 20 x 8.

Elson

Hello Elson,
Thanks for your feedback.
Well at the moment I am still debating whether I should go for the Hosteler version of the Tri Pacer or do my own stuff. From a thread I was following one Tri Pacer was weighing about 17kgs (approx 37.5 lbs) and wondered if at that weight the 42i would still pull it around the air (without aerobatics). Anyhow, thanks for your reply, it is appreciated.

Reuben

Reuben,

At 35-40 lbs, you are on the upper end of the 3W-42 ability to fly the plane. A 3W-50 would fly the plane very nicely.

That is what I thought. I think I had better make it a smaller plane as I do wish to use these 42i engines as they have been gathering dust for much too long time! Thanks again.
Reuben