Greetings,

I would like to know what opinions there are about whether to use a 2 or 4 stroke in a sport ship I built from plans. It is called a fantasy and I have never seen it before, can't find anything on the web either. I would say it is a large 40 to 60 size but has a small engine bay. I love the sound of the 4 strokes but am unsure of what size 4 stroke would get the job done in a small space. It currently has a magnum 40 in it, little tight on the fit, and on the maiden flight the instructor said it felt under powered, so I am looking at the .52 size engines; 4 and 2 stroke. Any ideas?

vr/
Kevin

i believe it's the same plane as the skyshark fantasy. use to quite promoted on RCU but has been quiet for a while. it is an older design that skyshark now kits for the diyer.

http://www.skysharkrc.com/fantasy.htm

you will see that your engine is not even in the recommended range. although i am not an advocate for overpowering planes, i do tend to lean toward the larger of the recommended engines. i would say at least go for an OS FS-70SII or a saito 82 both 4-strokes. i think you'll have a really hard time shoe-horning a 91 in there but you can try. a magnum or tt 91, both great engines. for 2-strokes, a 52 would be fine but i'd go for the O.S. 46AX... one of the best engines available. a ~75 would be good, too.

but it would also depend on how heavy your plane is. each builder will tend to build differently. my attempts at building were always a lb over the designed weight. made for less than stellar performance :-)

what intrigues me is how you have the plane balanced with a 40? would seem to me that it would be very tail heavy...

Well if the Magnum-40 is a tight fit larger engines are gonna be REAL tight! I like the TT Pro-46 for 2 cycles and as mentioned a Saito-72/82 if it'll fit-

Nice brd!

my all time favorite isthe ys 63 4 stroke. a lot of power for its size. always very reliable for me

OS .50 SX ringed...

I have three of them (two plane versions and one heli version), they are great engines...

I put a tower pipe on my OS .46fx for $15 and gained 500-600 rpm. It turns a 12x4 at 13400 on my setup. That would be a lot stronger than what you have and it should fit fine.

get an irvine 46 orea 56 there reliable 1 of the most powerful and sporty

I knew I'd find the answer here. You are absolutly right forestroke, that is the plane. I think I'll take some measurements and get technical about this engine install. Thanks for all the help everyone.

Kevin

A saito .72 has the same mounting demensions as a saito .56. The .82 (I believe) has the same footprint as the .100. I doubt you could get the .82 in, but the .72 would probably fit nicely. I installed a .72 in my contender which also is a very tight fit, and it went in perfectly. Plenty of power, as well!

The .82 saito is the same block as the .72 same weight even it just has more power. However the bore is the same as the 100 it is the stroke that changed.