Mr67Stang

Who's got a design for a 3D capable spad that will perform well with an OS .40 LA. Maybey a SPADDD that can be scaled down a notch? Or should I just go scratch out some SPAD Profile? Now that sounds interesting if not easy.

foodstick

I like the os 40fp, and LA40 ...but I don't think either of those motors is truly capable of 3D with even a frail balsa airframe...

They are just a weak but reliable motor.. I personally always liked and trusted my FP40 more than about any old motor I ever owned...but its no powerhouse..
My buddy always said FP stood for "FFFFing Piece" hahahah

Mr67Stang

That's one of the reasons I am interested in trying this. Everyone dogs on that little work pony (not quite a work horse). A buddy of mine has a Hobbico Superstar trainer with one and he said it could not take off from our grass runway. Yesurday I convinced him to bring the plane to the feild. I removed his 10x7 prop and installed a 10x6 tweaked the needle and the plane was airborne in 25 ft. You just gotta know how to treat these little engines.

foodstick

It would be interesting to know what the prop thrust is for a LA40 ?

that would give you a number to shoot for to achieve even a 1 to 1 thrust to weight ratio....

draftman1

try the QHOR, the .25 size plane. try a 11-4, it just might do it. the QHOR is a basic beginner type of 3D plane but they are alot of fun!

icerinkdad

Bingo on the 11-4 or even a 10-4. Many folks dont seem to understand that a lower pitch prop gives more low speed thrust. Think of it as a transmission... in low gear (low pitch) the prop generates lots of air movement but at lower speed. In high gear (high pitch of 6, 7, 8 or more) there is very little useable thrust till the plane is up to speed. In the best of all worlds we would have a variable pitch prop like on the old airliners and run control line single speed engines.
Bob

spaceworm

I have a Hanger 9 Tribute powered by an Evolution .36 that flies great. I am going to build a SPAD version as soon as I can get some 2mm Coro. I have plenty of 4mm.

Dave McDonald

My Feedback: (19)

Here are two Spad designs that will truly fly 3D with a 40LA spinning a 10x4 or 11x4 prop. Replacing the stock muffler with a mousse can pipe will substantially increase the power and improve the throttling characteristics.

1.) McDDD
plans: http://image2-3.rcuniverse.com/e1/fo...78/Ol31413.jpg
video: http://www.spadtothebone.com/videos/mcdddfunflying.wmv


2.) PBF
plans: http://mypage.yhti.net/~dmcdnld/pizzabox.htm
video: http://www.youtube.com/watch?v=QjXJ0N4pIoo

Mr67Stang

I may have to try that McDDD.

Mr67Stang

Well, I started a Spad3dT. I decided to go with a 34 in wing and a 34 in fusalage. right inbetween the 25 size and the 46 size. Will report after first flight.

Dave McDonald

My Feedback: (19)

For 3D flying with a 40LA you will need to keep the weight under 3 1/2 pounds. With a 34" SPA3DT, that's going to be hard to do.

You might want to consider making a SPA3D instead. The U-channel is much lighter that the square tubing.

I'd recommend a 32" wing and a 32" fuselage. This will save some weight and make the plane easier to balance with a 40LA.

Use half span wire spars instead of full span wires to save weight. Better yet use carbon rods/tubes instead of the wires to save even more weight.

Skip the tailwheel to save a little weight.

Replace the aluminum landing gear with music wire to save more weight. 5/32" wire works great. 1/8" wire would save more weight but bends too easily.

Make the motor mount big enough to mount the engine.....and no bigger.

Mount the throttle servo in the U-channel, just in front of the aileron servo.

Use a lightweight battery. AAA NiMH battery packs only weighs a couple ounces.

If your goal is to fly 3D with a 40LA, then weight is going to be critical.

Mr67Stang

Okay, I got my Spad3DT done and flew it this weekend. I made a trim curcuit with it and noticed my engine was a little lean. So I bring it around to land and as soon as I touch down that F#$%^* cutting board motor mount snaps and my engine flopps to the ground. So I will now get some 1/4 inch ply and make a propper engine mount.

Dave McDonald

My Feedback: (19)

Congratulations on getting your SPA3DT built and test flown!

But if "that F#$%^* cutting board motor mount" snapped, you most likely got the wrong type cutting board. And speaking from experience, plywood motor mounts break even easier.

Walmart sells two types of cutting boards that have nearly identical packaging. The only difference is that one says POLY in big letters, and the other one doesn't. If the cutting board package doesn't say POLY, or HDPE, then it's the wrong one and will easily break.

spaceworm

HDPE is high density polyethylene, which is good. The ones marked "Poly" are also likely this material. No marking likely is polystyrene (PS) or PVC (poly vinyl chloride) which are much more brittle and not suitable (IMHO) for firewalls.

Villa

Hi Mr67Stang
I had that plane and on my worst day I broke 5 props. Every time I broke the 7/16 thick POLY engine mount I made it a little wider in the area that it broke. I never had the throttle servo in the engine mount. I mounted the servo inside the wing, on the bottom side. It is very difficult to make a decent landing with that model because the stall is unpredictable. That is why the main gear is so tall. Don't judge SPADS by that model. I have had a Biplane with an OS 46 AX and 12 X 4 APC prop for about 2 years and fly it frequently. I have yet to have a bad landing with it. It even does 3D, but I'm not good at it.

Villa

Hi Mr67Stang
I had that plane and on my worst day I broke 5 props. Every time I broke the 7/16 thick POLY engine mount I made it a little wider in the area that it broke. I never had the throttle servo in the engine mount. I mounted the servo inside the wing, on the bottom side. It is very difficult to make a decent landing with that model because the stall is unpredictable. That is why the main gear is so tall. Don't judge SPADS by that model. I have had a Biplane with an OS 46 AX and 12 X 4 APC prop for about 2 years and fly it frequently. I have yet to have a bad landing with it. It even does 3D, but I'm not good at it. It is posted here.

Mr67Stang

The plane was not hard to fly or difficult to land. It was actually a little gusty and was less effected than my 60 size twist I flew after the mount broke. It was a reletively gentle touch down and the beam portion of the mount just snapped. I think the Cutting board does say POLY on it but, I will have to look when I get home.

I'm not discouraged from SPAD's at all by this. I had a SPAD Deamon a few years ago and after building three wings for it I finally gave up on that design. I liked the way it flew because the flat spins were amazing. But my engine would die in the spin and I could not get it out without power. So I broke a wing everytime I did the flat spin.

PatrickCurry

My Feedback: (20)

"Hey Doc, my arm hurts when I go like this...." "Don't go like that..." Sorry, just a little Rodney Dangerfield.

Mr67Stang

Oh ya. Old enough to know the Rodney Dangerfield routine. And that's what I did. I really only like the plane for it's flat spins and it hurt every time I did it. So I quit that plane. Ultimate bipes are pretty goot at that flat spin thing too and my Twist 60 can do it without losing altitude, weird huh...

spaceworm

When you cut the u shaped cutout in the poly for the engine, did you make a nice radius at the ends of the cuts? Sharp corners or worse, a little overcut at the corners, will create stress riser points and maybe crack/break just from engine vibration. Just a random thought. Good luck.

rcflyingnut

My Feedback: (9)

This is a Spadtothebone Qhor up to a 30 size. I started with a K&B 28, but all it was was a fast 3 wheel propped car! Put this OS 40LA and it will do everything I want it to. Won't give it unlimited verticle, but the flat spins are fun and tuff as nails.

Villa

Hi Mr67Stang
If you want to pioneer a SPAD Profile, you might want to look at my SPAD Bi-Plane I have posted on this forum. It is a profile, and there are some light weight ideas there. Drop one wing and make the remaining wing a little larger and you have it. I used waxed string instead of glue and even though I frequently snap roll it at full speed nothing has come apart yet. My OS46FX with 12 X 4 prop will hang it on the prop, but I'm not very good at 3D.