ckangaroo70

My Feedback: (51)

I just had a few questions I wanted to ask about the Sig 1/4 Scale Clipped Wing Cub I am building. I am sure there are plenty of folk on here that have some experiences with this particular Plane. I have the Plane pretty well Framed up, and just needing some finish sanding, a little painting, and the glass installed, and then it will be ready to cover. 1st question is: What would be the best route to go on the covering? Monokote/Ultrakote, or fabric, and why? I have also been debating on converting a new Mac 32cc weedeater engine I have into a powerplant for this Plane. 2nd Question: Is this a good idea or bad, and if bad, what would be a good alternative without busting the bank. 3rd Question: How well does the Plane ground handle, and does it have a bad tendency to nose over? 4th Question: Are there any weaK spots in the design that should be addressed before the covering is put on? 5th Question: I have some big High Torque Giant Scale FMA S400 servos set aside to use in this Plane. Is this overkill, and unnessasary weight, or are these a must? 6th Question: Does it have to be flown in, or does it float in on landings? Any good tips or advice would be appreciated. I have many airplanes in the hangar, but I have never flown a cub, and I have more hours than I care to remember just getting to where I am at now on it. Good advise and tips will just help increase my odds for a successful maiden flight with it come spring.

CK1

My Feedback: (60)

ckangaroo , I have built and flown a few Sig cubs and i can tell you that you're gonna love it .
I would recommend covering with fabric (solartex is my preference for pre-colored)
Fabric is a little heavier than Monocote but much more durable .
As far as an engine choice i would recommend a 1.20 -1.80 4 stroke for 2 reasons
1-realistic sound
2- save weight (i have used gas engines and usually have to add tail-weight even after placing batts and servos rearward, makes for a much heavier plane)
Ground handling is good if you are used to taildraggers - no bad tendency other than P-torque and possible ground loop for the unfamiliar pilot.
Basically the design is very solid without any needed mods . no real weak spots (remember build light ,not crash proof)
Giant scale servos work well for the elev. and rudder , but not totally needed , any servo above 70 oz/in would be sufficient
This plane is like all planes !QUOT!lighter is better!QUOT! ,if you build heavy you'll need to fly it in , if its light it will float like a trainer .
My best advise would be take your time !!
Set up all throws per plans , set C.G per plans . take your time to dial it in. set trim for level flight at 1/3 - 1/2 throttle - not wide open. This will let you get a good feel at landing vs that surprise stall and not enough elevator to save it. If you trim for level flight at full throttle you'll have trimmed in a lot of down elev that you
don't want while landing speed. Remember !QUOT!fly on the wing !QUOT! control climb with throttle and you'll do good.

ckangaroo70

My Feedback: (51)

Thanks for all the great info chris. Got some real good advise posted there, and I appreciate it.

rayb

My Feedback: (13)

Try this site http://www.geocities.com/cubmanky/main.html
Lots of good Cub stuff here

khodges

My Feedback: (1)

Mines 1/5, shouldn't be much different than 1/4 in flying, mine is full span. I prefer to land with about 2-3 clicks of throttle, let it settle on its own, and as soon as the mains touch cut throttle to idle; stay on the rudder to keep straight, let the tail settle on its own, but be ready with the elevator if it looks like the tail is coming up (sometimes thick or not-recently-mowed grass will "slam on the brakes" for you and it will try to ground loop, but if you stay ahead of the plane it makes a beautiful wheel landing. Take offs are easier if you roll on the throttle, let it roll a while and let the tail come up by itself, then just nudge the elevator and it will fly itself off. Yuo're gonna love this plane.

khodges

My Feedback: (1)

I had more to say but had to pick up my daughter from Brownies. The above post applies to still air, upwind or downwind; I found that if you try to let it "float in " coming downwind, the ground speed will fool you, and all of a sudden it stalls and drops so carrying power on a downwind is much safer, but it will be a "hotter" touchdown. On upwind approaches, I still keep power on and fly it to the ground. The full span is a real floater in a breeze, I can come in with 3 clicks of throttle , cut power when I touch, and the rollout is about 3 feet in a 5 kt. headwind. Crosswinds can be fun, you can cross the controls and sideslip into the wind, straighten up on short final, just make sure to keep the upwind wing a tad low. Since your plane will be heavier and the wing loading greater, these tendencies may be milder than they are on my plane, but they'll still be there, 'cause it's a Cub.

khodges

My Feedback: (1)

I keep thinking of stuff. When I was building mine, an old timer at our field recommended that I reinforce the cabin roof supports (the angled"A" pillars, and the window framing vertical members) he said he had owned about a dozen Cubs over the years, and they all had a tendency to shear these if it came in hard on a wingtip (torsional shear) and the center section would come off. Once this happened, he said, it was difficult to repair and keep the wing alignment correct. I reinforced the verticals on mine with 1/4 inch hardwood dowels epoxied to the "factory" uprights, and used 1/4 x 1/16 carbon fiber strips on the underside of the "A" pillar, from the floor to the spar. I figure the weight is a small trade off for the extra strength. I modified the center section extensively on mine to make the "greenhouse" to convert my Cub to a L-4.

ckangaroo70

My Feedback: (51)

Thanks for the tips. That is a sweet looking Plane KHodges. I've been working on mine for 2 years and it is time to get it done. I have a pretty full Hangar, and this project always seems to get put on the back burner. 2 years of anticipation is enough, and I want to try to get this Plane ready for spring. I just bought a new Saito 1.00 for my Edge 540, so its time to start saving again for a engine for the Cub. I am considering a Magnum 1.20 4 stroke for this Plane, or a Mac gasser, but the 4 stroke seems to be the engine of choice for these. I have a smaller Magnum 52 4stroke on a smaller Scale Plane that I own, and I think the magnums have a more scale sound then the Saitos. The Saitos are a good engine, and I have two in the Hangar(.72 GK and Saito 1.00), but I think I may go Magnum for this Plane if I go 4stroke instead of gas. The question I have, is the 1.20 enough engine for this Plane?

khodges

My Feedback: (1)

How much will it weigh? The recommended range for mine (4-stroke) was up to a .60, but that was for its projected weight of 7 pounds max. Mine weighs 9-1/2 due to the mods, scale gear, on board glow, etc. and a .65 flies the hell out of it, turning a scale 14 inch prop. Scale prop on your plane is 18 inches(1/4 of 72), I'd say a 1.20 should spin it okay, at the very least better than scale power/wt.