What size engine???
 

Hi there guys,

I'm sure that i'm repeating a topic that has already been killed to death in this forum, but if you don't mind, I would really like to hear your opinion. I am planning on building a Coal Hauler funfly with a recomended engine size of .25 to .40. I would like the build the aircraft with the best power to weight ratio. What engine would you recommend I install???

have you got any tips on how I can save weight when building the aircraft and also particularly on the muffler.

THanks!!!

RE: What size engine???
 

What's a Coast Hauler Funfly?

RE: What size engine???
 

Its one of those boom type fun fly airplanes. It's made by a company called Florio Flyer. Its basicall a semi symetrical airfoil constructed around a thin carbon boom with VERY extreme control surfaces. It really needs to be built as light as possible to extract full performance from this extreme aircraft.

RE: What size engine???
 

What size is the plane (wingspan)? and What weight do they advertise the plane at?

A good BB .46-.50 is good for a 4.25-5lb airplane and for 3-3.5lb think about a .32-.36

RE: What size engine???
 

A 32SX is spendy but has more power than most 40s. I really like mine.

Only weighs 9.5 oz.

RE: What size engine???
 

I like the Webra .32 and .50

RE: What size engine???
 

Ditto on the OS. On my 3lbs competition fun fly I use a Irvine .39 with a Yusa tuned pipe. A throttle pipe is usually better for these. Or if you plan on using a Irvine .39 you will be better off with the proper Irvine pipe made for the motor. Other option which is not listed is the West .36 with the throttle pipe. Very powerfull and very light motor.

RE: What size engine???
 

bhole, the 32sx engine is a heli engine isn't it?? If thats what you use, would you change the head??

Spacy, Just wondering what is a Throttle Pipe?? And what would the advantage of me using the Irvine .39 to a Webra .32 or O.S. .32sx engine??

RE: What size engine???
 

Uhmmm If memory serves the OS .32 SX-H is the heli motor. The SX is just the normal aircraft motor.

A throttle pipe is a pipe that will give you good throttle response through the whole rev range. A tuned pipe will most of the time only give you much higher revs but the motor will "climb" onto and off the pipe at a certain throttle position. Which is sometimes a drag on these planes. I have learned to work around it though.

We have proven on the plane I linked down at the bottom that the Irvine .39 out performs the OS .32 quite far. The weight penalty is virtually nothing, if not nothing. Although the West .36 puts out a 1000rpm more than the irvine swinging a Master airscrew 11X4. On my Irvine I get 14900 rpm with the MA 11X4. I don't know about the webra, although the west is a tweaked webra from what I understand.

Here is my comp Fun-Fly which is a South African designed plane. 50inch wingspan and weighes 3lbs.
http://www.spacey.rchomepage.com/images/Shotgun%205000/

RE: What size engine???
 

Ney Nova Bill, there is no weight they put it at, however it has a 46" wingspan.

RE: What size engine???
 

If it's an ARF, then weigh the airframe with all the components and your flight pack (everything except the motor) if it comes in at 3lb or less, go with the .32-.39 if more, put a Webra .50 in it

RE: What size engine???
 

Agreed William! :D As soon as you start going towards 3 pounds all up weight without motor you're reaching limits of a .32 to .39 sized motor (Please note I do not mention a .40! Because they suck! :D) If you are going over 3 pounds without the motor you start looking at .46 to .53 sized motors.

RE: What size engine???
 

Deanoo, Spacey is correct. The 32SX-H is the heli engine, the 32SX is the aircraft version. It has the same mounting pattern and dimensions as the 25 fx (for the most part) but a lot more power. I am running a 10X6 airscrew at nearly 13,000 RPM on a 4lb. TT Lazy Tiger 51. It will hang on the prop.

RE: What size engine???
 

And the West .50 and Webra .50 are the lightest:D I want a West .50. My Wedra has been soo good and from what I have heard the tweaking just makes it that much better.

RE: What size engine???
 

Thanks guys for all your help. I'm going to look at either the Irvine .39 or the West .50 depending on the weight. Hopefully I will let you a know what I've cum up with.

Cheers!!!

RE: What size engine???
 

What's a "West 50"?

RE: What size engine???
 

It's a reworked Webra.

RE: What size engine???
 

Modelbau makes the West-50, a high rpm version and a torque version---the Webra-50GT is super light and instant throttle for a 50-

The Irvine-39 sounds impressive- I have the 46 and 53 and they are full of power on 5%Let us know what you decide-