I finally finished my SPAD biplane. I started on the design about 4 years ago. After I decided not to rebuild my Flying Lawnmower about 3 months ago I finally had the electronics for the biplane so I finished the design. A lot of work. Getting the wing incidences both at zero, along with the horizontal stab and engine, made this my most difficult build. It has a profile fuselage, WS = 42" and it came in at only 4.5 pounds. I use an OS 46AX with a 12X4 APC prop. I use four .157 diameter carbon fiber tubes in the two 4MM fuselage sides, running thru the flutes. The fuselage twists a little, but after 4 days of flying it seems to be OK. For the engine mount I used two cutting boards, 1/4" thick, sandwitched together so that one of the 1/4" thicknesses provided the 1/4" gap between the two 4MM coroplast fuselage sides. I was also able to tie the carbon fiber rods to the engine mount with .04 diameter waxed cord. Today I did vertical snap rolls, Lomcevacs, loops and rolls. I was alone so I'm not certain if there was excesive twisting. I'm prepared to add flying wires to the wings, but so far it does not seem to need them. Because I was not certain about my method of wing strut and caban strut mounting, I decided not to glue the wings in any manner. Instead I tied them with the .04 diameter waxed cord. I even tied the spars in place. I already took the top wing appart once to make needed mounting changes. I will slowly make more violent manuevers in the air to make certain there are no weaknesses. Attached are some photos.

Another attempt at posting the photos:

That looks awesome. Clearly your method of planning ahead and thinking things through is way better than my method of slap it together and hope it works.

That is a great looking plane. Your design looks very light and strong. I'd love to see a video of it in the air.

Great job.

Very cool plane! Keep us posted on the changes you decide to make. Are you planning to put together some plans? I need something to tinker with once the weather gets bad here.

Hi mclina
I like to solve the problems on paper first, since that is the easiest way. I get a lot of pleasure designing the planes. I believe I have some designs I may never build, but did enjoy "building" them on paper.

As I mentioned in my original post, I use a profile fuselage made of 4MM coro spaced 1/4" apart, with two .157 diameter carbon fiber rods thru the flutes of each of the two sides for stiffness. I have been disappointed that the fuselage did not stiffen up as much as I expected. I use three "bulkheads" between the two coro sides plus I tie in the long carbon rods to these bulkheads for further stiffening. After many days of thinking about it I decided that the carbon fiber rods had to be slipping in the coro flutes as the fuselage was being twisted. The movement would be very small, and I could not detect it visually. Well, after about 6 flights and not liking the wimpy fuselage, I dripped some Gap Filling CA glue into each flute that had a carbon fiber rod until some leaked out the other end. The fuselage is MUCH stiffer now. In the future the CA glue must be added before using string to tie the rods down in order that the CA glue can flow the full length of the rod in the flute. I was forced to drip it in from both ends of the rods.

Hi TruBlu02
I'm not too encouraged about putting up plans. It requires a LOT of work. I put up plans for my SPAD Canard and SPAD Flying Lawnmower, and I have yet to hear from one person that has built one. I will gladly answer any questions. I have flown both of those planes for about 5 years and they are still very exciting to fly. Both are extremly easy to build and the designs are tough as nails. Flying them is a little different, but not difficult. So what is the problem? Here are some photos of my new SPAD Biplane in the air.

I would not be discouraged because you don't hear back from people about your plans. I have experienced a similar phenomenon in this hobby. It turns out modelers are a pretty independent bunch that are very busy and if they can figure it out themselves they will. I later found out that my efforts were actually greatly appreciated but I never heard anything most of the time.

Hi AGR413. Thanks for your input.

Yesterday I replaced the heavy bronze prop nut with the aluminum one I prefer, plus I removed about 16 square inches of 4MM coroplast I had glued under the hor stab tips for reinforcement. I took it up and did a little trimming and it flew fairly OK. The wind was terrible, though, so I could not decide if the CG was good. At some points in turns it acted like a wingtip stall or a tail heavy condition, but because of the wind gusts from all directions, I could not decide on any changes. It is more limber in flair, as expected. I did make some high speed snap rolls over a safe area and everything held together. Repeated it about 6 times. In knife edge the rudder seemed to have a little more authority but not too much which pointed to the CG possibly being OK. The carbon rods and string seem to be holding up. I'm waiting for a calmer day to confirm the CG.

I have always thought that a biplane can be just about the most exciting plane at the field. Very few people have them though. They are a little harder to build, and probably much harder to repair. For that last reason I think they are a natural for a SPAD, since needed SPAD repairs are few and far between. I have about 30 flights with my new one and not one mishap. I had a hard time when I built mine when it came to aligning the wings. Both wings were set at zero incidences which meant they had to be parallel to each other. It is very easy to state the requirements but the feat in itself can be daunting. I aligned things, then tied everything together (I chose putting everything together with string rather than with glue so I could change my mind) then checked the alignment with the incidence meter and things were off. I had to cut things lose and start over. This had to be repeated a few times. It became frustrating. I was fortunate in that I had built two biplane kits (not ARFs) about twenty and ten years ago so I knew how the alignment was done on a kit, plus I still had the plans to study and had noted that the alignment was built into the kit. All that was needed was to build the kit accurately. The way we build our SPADS can make alignment very interesting (difficult). As I finished my biplane and flew it many times, I kept in mind the desire to make the alignment easier, more full- proof, a bit automatic; built-in as in the kits I had built.
I came up with an idea that makes the three struts alignment fixtures. The struts include wing ribs at their ends, top and bottom, plus the proper angle to arrive at the correct wing stagger. Since I still saw plenty of problems ahead I decided to build a wing assembly; two wings and three struts assembled to make one sturdy unit, so I could solve some of these problems. Here are some photos I took along the way. As is usually the case, there are still problems to be solved. The top wing is glued together but the bottom wing is not yet glued. Somehow a warp occurred while clamping the top wing closed and this deviation is now amplified in the bottom wing. The ideal situation was to glue the top and bottoms wings at the same time, and make adjustments as needed before the glue dried. However, I would have needed a lot more hands. I’m now thinking of ungluing the top wing, make the warp correction, and then assemble everything with a combination of just a little glue and lots of strings. The assembly as it is now feels much more rigid than the wings on my flying biplane. The new wing assembly can be mounted to my biplane by removing the left wheel strut, the fuel tank, two bolts, and cutting some strings. Glad to hear any comments, questions, or suggestions.

Vills,
I am flying my SPAD racer now. It has a profile fuse with 3/4" pink foam sandwiched in-between 2 pieces of 4MM coro. I cut out parts of the foam and glued in 3/4" thick pine wood for hardpoints. Flutes run longways down the fuse. It's pretty stiff and light.
Hope that helps.
Chris

Hi batchelc
Your method sounds like a good idea. What glue do you use between the foam and the coro, and between the foam and the wood?

I used a water based contact cement between the coro and foam but to do it again I would use poly glue. I used the poly glue between the wood and the foam.

I just noticed that somehow I did not post the details of the struts I used. In the photo you see the ribs that I glue to each side of the strut and the slot that I cut into this assembly to accept the spar. This slot is shown only on one end of the strut assembly. The struts must be then assembled thru slots in the bottom of the top wing and thru the top of the bottom wing. Then the rest of the ribs can be glued to the struts, being careful to align everything with the spar lines. Now the rest of the spar slots are cut. For this last step I needed my wife to hold the wing while I did the sawing. Because of the cutout accuracy required and the many curves involved, I cut the struts and ribs out using a coping saw with a fine toothed blade. It worked surprisingly well.

The SPADS are TOUGH!!! Last Friday the wind was gusting up around 20-30MPH. It has been difficult finding a calm day lately. Either fly in the wind and take a chance, or park it. I had my SPAD biplane up and it got too far away on me as I was struggling with the wind (lack of attention). I thought I was going to lose it because I was not seeing it very clearly. I gave it up elevator and full throttle; a few stick movements and I had it oriented. I brought it back, got into the landing pattern and forced it into final. She was bucking like a bronco and rolling 90 degrees each way. I became so fixated with controlling the plane that I came in early. Missed the end of the field by about 8 feet and hit the tall grass/brush with the throttle about 50%. One wing hit before the other and it spun 180 degrees and stopped. A balsa plane would have been history. I saw no damage. I grabbed the plane by the prop and shook it hard to make sure the fuel clunk was positioned correctly. I did not have the nerve for another flight. This last one was my third flight that day and I was spent. On many of my SPADS I have struggle over a long period to make changes to get them to fly right/better. On this biplane I initially made a few changes to optimize the CG and since then it has been perfect. Not once has there been any hint of a tip stall. I have had two balsa biplanes of similar size that I built from kits and they both would occasionally stall on landing and get damaged. I don’t know what is different with this one but even others have commented on how steady this one seems to always be. A friend who has many balsa biplanes stated that biplanes have to be landed a little “hot� or they will tip stall. I agreed with him, but this one seems to be the exception. Very responsive, very predictable, very steady. I don't know why. I keep looking and wondering. I'm waiting for snow so I can fly it with my DuBro skis.

looking great. but m,e n plastic dont get on i love wood especialy the smell of fresh balsa and pva itr wakes me up in the morning aswell as a cup of coffee.

Sweet looking Bipe!
I was scanning through your instructions and comments, looking close-up at the wings I noticed It's not coroplast being used.
What material are you using for the wing construction?

Thanks
BB

Hi balloonbandit
Each of the two wings is made of 2MM Coroplast, with the flutes running cord-wise. The three struts with ribs, and ailerons are made of 4MM Coroplast. Are you going to try to build it? I have two friends that plan on building it soon. I'm anxious to get another opinion on my method of building the two wings so they end up parallel with little added effort. One of these days I will put a sunburst decal on the top of the top wing. Our club has our yearly Chili Fly-in tomorrow and I'll be flying the biplane in the morning and afternoon. So far no snow to test my new skis on it.

I believe I shall give it a try. My hobby-time is sparse so don't anticipate a quick build from me. I'll be going electric because it is easier to find flight space around here. If you would like snow to try your skis, come on up to my area. (Northern Indiana) It is snowing even now, and we already have about 5" to 7" on the ground. I'd be happy to send some snow your way if I could!

Cliff

Hi balloonbandit
I saw plenty of snow when I was in college in Fort Wayne, Indiana, many moons ago. Good luck with your build.

Indeed Ft Wayne is about 45 minutes east from here, plenty of normal snow but not much "lake effect" which can add a few inches.
The photo of your 3 struts appear to have some type of dowel or carbon rods in a couple of the flutes, added for extra strength no doubt? Would you be willing to post or send some of the dimensions on the main wings and struts please?

Cliff

Hi balloonbandit
Send me a PM with your e-mail and I'll send you some drawings. Let me know here that you did it so I look for it.

You bet! PM'd

Thank you

As I have mentioned before, I have been waiting for some snow so I could try out the Dubro skis I purchase for last year. Last year we had zero snow. About 2 weeks ago we had a lot of snow but I was in bed with a stomach attack that made me wondering what peanut butter product I may have been eating. Well, three days ago we had some more snow and I just had to go since we may not have any more snow this year. I put the skis on my SPAD Biplane and drove out to our field. On the drive out I noticed three American flags on flag poles; two were straight out and the third looked like it was straight out plus maybe 5-10 degrees further up. I never have noticed that before. At the field the wind sock was straight out but seemed steady. My guess was 30 MPH. As I carried the plane in my left hand and my flight box in my right hand, I was facing down to reduce the wind load on my face. I noticed the wind was blowing the fine grained snow at a high rate, just over the ground. I also noticed that as I was walking I was leaning into the wind. Then the plane started dancing all over the place and I was afraid it would get away from me. Finally I told myself this was ridicules, returned to my warm car, and went home. I took the attached photo in my back yard after I got home. I hope I'll get a ski flight in this year.

Don't blame You one bit Villa, usually My cut off point is; if I set My Spad down crosswise to the wind, and the wind blows it over on it's back; it's too windy

Hope the weather cooperates soon.
Jeff