brent0609

Hi, I'm building a 1/5th sig cub. Have recently set up firewall and engine mounts for a evolution trainer engine. I believe this motor closer to 46 then 40 in specs.Kit instructions rate it 40-46 and advise not to overpower.Seems that in most threads bigger motors are used on cubs or 4 strokes. This motor came with my alpha trainer. Also worked great on my slowpoke "awaiting wing kit" wonder if it will ever come.
Anyone else use a 40-46 on there 1/5th cub?Also dream of flying off water ,might lack the power with this motor though?
Other thing is i have experienced dead sticks i believe due to my inexperience with engine tuning.Ive been in the hobby since last may.Might be wise to save up for a four stroke for reliability? Thing is i already have this evolution and would like to use it. Opinions appreciated thanks.

khodges

My Feedback: (1)

Two-stroke or four stroke, the choice is yours. I'm a 4-stroke fan myself, except for my trainer all I have is 4-strokes. Personally, I think a Cub begs for a 4-stroke. A .56 is adequate for scale flight, but a .65 or .72 gives you some reserve power, plus allows you to just putt around at low throttle settings. I have the 1/5 sig, love it, and have a .65 Saito in it. A .46 2-stroke will fly it, but I think you will be wanting a little more oomph after you've flown it a while with the smaller engine. Just my $.02.

bluebikerblan

The Saito .65 is a very popular choice with the Sig 1/5 J-3 Cub. That's what I've got also. I've noted that a number of people go even larger with the clipped wing version and I imagine they might want to do so with floats but I've no experience in that regard. It's a great combo however. BOL and enjoy. I really liked the kit and the build. Hope you do too.

FlyingPilgrim

My Feedback: (26)

I would say a .70 or .72 4-stoke would be ideal.

brent0609

Ok , thanks for the advice gents. Went to to the LHS with fairly firm intentions of getting a 4 stroke 65. After lengthy conversation went with a 2 stroke evolution 60. Now am being challenged mounting it. Have knocked out blind nuts, and need to glue dowls in there. Made pattern for the 60 but doesn't fit easy.9 oclk mount is above firewall. 12 oclk almost entire thing is going to stick out of cowl. 6 oclk mounts to high on firewall. Is cutting mount down and drilling new holes in it a bad idea? also maybe i should get pitts muffler before deciding.Thinking new motor mount is the answer. Will be going back to LHS soon with firewall, engine, and my mounting pattern.By the way i'm getting close to finishing 2nd wing section.Will need to get back to the fuslage and this is step one .
PS: What's "BOL"? build out loud?
Thanks

khodges

My Feedback: (1)

Did he (LHS guy) talk you into the Evo because it's what he had on the shelf? It ought to to be enough power, for sure. Side mounting the two stroke is probably your best option, a fair compromise between aesthetics and reliable running. Mount it with the cylinder to the right.

I'm curious to know what the LHS guy said to convince you to go 2-stroke. They may take a little more work to set up well, but it's worth the work, and not difficult. You may have to try a different engine mount to get it (the Evo) to fit. My inverted .65 in my Sig came close to the top of the firewall, but the engine is almost totally enclosed within the cowl. I used a DuBro antivibe mount. On my H-9 Cub I used a Dave Brown mount, and I recommend it highly. The part that goes against the firewall is round, and has marks you line up on the crossmarks that you make on the firewall to center your engine, makes it easy to center everything.

Gray Beard

My Feedback: (-1)

I would like to know what he said too, A 60 is A lot of poop to pull that light little plane around. I have had two engines in mine, an OS 70 four stroke and A Thunder Tiger 46. I liked the 70 best but it was over powered even with that. The 46 was better but it just didn't sound right and tended to dead stick too often so I went back to the 70 only installed it inverted this time. Fit better inverted and after tuning it I have never had another dead stick. Still over powered though.

tailskid

My Feedback: (34)

I flew mine with an OS .52 and it flew VERY scale-like and didn't have any problems flying off grass.

brent0609

The discussion at the LHS was something to the effect that a 65 4 stroke was close to a 46 in power.46 power and "what is the wing span 84"? maybe not enough. Sound isn't a issue for me right now, i just want it to fly well. Would have to upgrade to 80 4 stroke for more power. Also i'm fairly new to all this and expressed a interest in less engine tuning and dead sticks.That was a big part of it.
Khodges the round mount looks like there's lots of fire wall room left. Tailskid doesn't top right engine mount bolt. Come threw were stringers attach on back side? looks like mount is right to the top.+ Did you drop the thrust line a little bit?
Thanks

khodges

My Feedback: (1)

I really like the Dave Brown mounts (round one). I also like the DuBro, but it takes up more space behind the engine. I had to recess the firewall on the L-4 for that mount to work, and even if the mount comes right to the edge of the firewall, with the cowl in place it won't be seen. I did not drop the thrust line, as I was trying to maintain a very scale appearance; since the boot cowl slopes down a little along the top, recessing the firewall actually gave me a little more room at the top of the firewall.

As far as the LHS guy goes, it clearly says on the kit box the recommended range for the plane, and I've found that the mfg generally knows pretty well what will fly their model. He's correct that the .65 is close to the .46 in power, but we're talking peak power at WOT, not real world midrange running, which is what you'd be doing most of the time; plus, the .65 would turn a larger diameter prop (scale for the 1/5 Cub is a 14 incher) and the .65 would do a better job IMO, than the 2-stroke. I wonder if the LHS would let you return it if you haven't run it yet? That is, if you really want to, it's really not a big deal. I'm just a dyed-in-the-wool 4-stroker and am prejudiced in their favor. I like the way they perform, and for my own wants they are the perfect engine.

tailskid

My Feedback: (34)

"Tailskid doesn't top right engine mount bolt. Come threw were stringers attach on back side? looks like mount is right to the top.+ Did you drop the thrust line a little bit?
Thanks"

Yep, a bit of the motor mount was grinded and it was a tight fit to get that blind nut in there, but it fit! I tried NOT to change the thrust line and did the best I could and the way it flys, it appears to be right on.

Jerry

MinnFlyer

My Feedback: (4)

If you haven't run that Evo, I'd take it back and get a 70ish 4-stroke.

Whatever the difference is money-wise, you'll save in Fuel the first season.

Not to mention that you'll have a MUCH better engine!