Villa

After my twin engine Great Planes P-38 fell apart in the air, twice, due to the weak booms, I put the components in a Twin SPAD plane I designed. The wing is from the Dominator, but the wing tips are square to get the full 48 inch span. Three hard points were glued to the two yard stick spars for 1/4-20 NC steel bolts, and nylon bolts were used at three points at the trailing end of the wing. The fuselage and engine mount supports are the aluminum channel from a SPAD3D and the engine mounts are from the POLY cutting boards. Flys better than the P-38. The other servos, battery, and receiver are stuffed inside the wing. About 7 pounds. Have even made 4 takeoffs on one engine (to practice one engine flying), but lost it each time on the first turn. Our field is like a soup bowl which makes the one engine takeoff a terror. I have shelved that effort for a while. Loops, rolls, snap rolls, and knife edges are great. The sound of the two engines going in and out of sync is super. The engines are Maxum .28.

sahoy

very cool spad!!!!!!

secondchildhood

My Feedback: (13)

Very cool design there. Looks like you have plenty of rudder authority to cope with any engine out situations. Is there any chance that you could take a pic of the landing gear detail. It appears from the pic you have that it is a taildragger and the mains are each attached to the bottom of the engine mounts similar to the qhor and spa3d design.

The sound of a twin on a fly by is worth the price of admission in itself!

Dwight Hayden

Villa

secondhandchildhood.....You guessed right on the landing gear. It is a tail dragger. The mains are of the 5/32 diameter torsion bar design like many low wing models have. They attach to the bottom of the POLY motor mounts. I just remembered the two throttle servos are not inside the wing, but attach to the bottom of the wing. Soon I plan to convert the plane to a twin boom model with one engine pulling and one engine pushing. I hope to then make the wing a little deeper so there is more room for the equipment. The plane will either be a tail dragger or a tricycle design, as dictated by what is required to balance it out. The wing has to move back quite a bit with one engine at the back of the wing. I do not have a camera so there are no more photos.

Col. K0rn

My Feedback: (1)

I second sahoy's comments. VERY COOL!

Curious, how much weight did you have to add to the tail end in order to get it to balance out?

DLSmith2

Hot tamale what a cool plane!!!

Great job Villa! If you could post a few more pictures about the hard points, etc. it would be greatle appreciated! I'm having trouble visualizing what you're talking about, never having built a twin, but would sure like to build one like yours!

Thanks for the picture and write-up!

Blue skies,
DL

Villa

Col. KOrn...There is no added weight at the tail. To balance it, I started with the suggested balance point for the wing of the DOMINATOR. I assembled everything, but just tied the fuselage to the wing. I then moved the tail back and forth till it balanced. I was looking for a total length that "looked about right". I moved the two rear servos as needed. Then I drilled the aluminum channels and bolted things together.
DLSmith2....The hard points consist of a square of hard wood about 5/8 inch thick that fits between the two yardstick spars as shown on the wing plans for the DOMINATOR spad., glued in place. Drill a 5/16 hole in the center of the squares and insert a 1/4-20 NC blind nut from the top of the wing. "Hard Point" is a term used in full scale aircraft such as a fighter to define a point on the wing that has been reinforced to carry a load such as a bomb.

Villa

To Rafael Castaneda. You can see my SPAD twin above. I stripped my GP P-38 and built the Spad Twin. The wing is from the SPAD DOMINATOR in the ORIGINAL SPADS section of www.spadtothebone.com. I left the wing tips square and added to the ailerons to make them 1-1/2 inch in the chord direction. The 4MM COROPLAS material is used for the wing and tail surfaces. I purchased it from Harbor Sales at http://www.harborsales.net/index.cfm? The material comes as a sheet 4 feet by 8 feet. Have them cut it in 4 pieces 2 feet by 4 feet, with the flutes running in the 2 feet direction. I used yellow but they have all popular colors. There is enough material there to make three wings and probably enough tails for three planes. My price delivered to my home was about $10.00 USA money. They take credit cards so you should be OK. Let me know if that works for you. It is best if you read up on how to build the SPADS by studying the DOMINATOR, the SPAD3D, and the SPAD3DT at spadtothebone.com. The fuselage is the same aluminum channel used on the SPAD3D. Same for the engine mounts. Mount the engine mounts at 4 degrees out like on the GP P-38. Study those plans carefully since siance many of the methods of construction are the same. Are you familiar with SPADS at all? If not, start reading about them in the SPAD section. I can give you some more of the dimensions if you still want to go this way. Let me know. The plane flys very well on one engine, but you have to IMMEDIATELY throttle down when one engine stops, take control, and decide what to do. Mine can even take-oof on one engine, but the first turn is a terror. Be glad to help others build this SPAD. Buena suerte.

737-700

Villa thanks for the info I will keep you informed


Muchas Gracias

Kripto

Very cool spad[8D]

Ed

737-700

Villa, how about close up pictures of the different parts of your SPAD? You know a picture is worth......



Thanks in advance

737-700

Villa I read by now that you do not have a camera, I have read about the SPA3DT and definitely I will build the twin spad, I will start ordering some materials(I already have the cutting table for engine mounts), and of course if you can send more measurements I will be always grateful, I saw the photos of the SPAD3DT and it looks not complicated, my question is how do you attach the two engine mounts to the main frame? What about stab and wing incidence? How do you hinge coroplast? I read the hinge tool tutorial but is not clear to me what is for?

Thanks in advance and sorry for asking to much

Villa

Rafael, The engine mounts are attached to the same type of aluminum channel that the fuselage is made of (the channel from the SPAD3D) That channel is attached to the hard point made from 1/2 inch thick aircraft plywood and 1/4-20 NC blind nut glued between the two yardsticks. I believe I explained this earlier. Correct? I used a steel bolt there, thru the channel from the bottom, and up into the blind nut inside the wing. The aluminum is also attached to the trailing edge of the wing, about 5/8th inch forward of the trailing edge, with a 1/4-20 NC nylon bolt. Use short pieces of 4MM bamboo skewers to keep the COROPLAS from crushing. This bolting is the same used to attach the fuselage to the wing. The cutting board engine mounts can be made a little lighter than on the SPAD3D which uses a .46 size engine. The mount is attached to the channel as per the SPAD3D. I chose to cut each mount with the 4 degrees of "out" thrust in the mount and bolt them straight to the channel. The wing and horizontal stabilizer are bolted to the top of the channel so the incidence is zero. There are a lot of instruction at this site and at spadtothebone.com for hingine the COROPLAS. Practice on scraps. I started by just using the standard hobby razor knife but this is very difficult. I then made the tool shown in spadtothebone consisting of two specially curved razor blades glued/bolted to 1/8 inch thick plywood. This works good, but I already have ruined work with it. The one I'm going to try next consists of a sled type tool that is PULLED thru a flute by a string. The tool consists of two standard hobby razor blades, with the tips ground down, glued to about a 1/8 inch plywood "sled". That word may be difficult for you to understand. I read about it in one of the forums, perhapse it was http://spadworld.net/. The COROPLAS is like cardboard. Cut the card board on one side only, in the direction of a flute, and it will easily bend at that point. That is your hinge. With COROPLAS you remove about a 3MM wide piece of plastic to make the hinge so that bending can occure in both directions without interferance. I'll get some more dimensions for you. Look up my thread under PULLER/PUSHER to see a great way to mount the servos, radio, and battery inside the wing. It is the same wing, but about 3/16 inch thicker to provide servo clearance.

fly boy2

I have come up with a few ideas for a twin. Tell me what ya think. I like the look of A but it might be too heavy, and I really dont know how I would do the engine pods.

draftman1

Hey Flyboy, my P-38 was like B but I am going to make a twin stick like C. the P-38 was all coro, no downspout, the wing was slid into slots on the twin booms. that way is good but you cant take it apart. version A might be too heavy, and really not needed. I will be doing mine this week. Im going to have it for "SPads over the West Coast" event in 3 weeks. as for the pods, I made another twin. I took an old wing and cut a spot out on each side for a short peice of dowspout, those were the pods. it workd really well
here is the link for the photo http://spadworld.net/gallery/display...6069&pos=-2516

Villa

Hi fly boy2
"A" is a brick, and "C" is the lightest. If you need ideas I suggest you search and read the SPAD forum below, plus spadworld.net and spadtothebone.com. If you have not built many SPADS, I suggest build some of the more popular ones. Flying a conventional twin can be very difficult due to the one engine out problem. Very, very few twins are flown. Every twin I ever saw crashed on the first flight, except mine. Mine crashed a few times when one engine stopped, but being a SPAD, each time it survived. With a good plan you can land a one-engine-out twin. What Spads have you built?

fly boy2

I have not build a single spad from scratch but I have rebuilt my deboniar which was givin to me. After I crashed it and then ripped the gear off, I decided to rebuild the fuse. I bought a 10ft piece of downspout and went to work. The hardest part for me would be to build the wings. I think I'll get some advice from a vet, 95% of his planes are spads. I did think of some ways of the on how to land with one engine. (1) if altitude and distance away permitting, to kill good engine and just have a deadstick. (2) other option is to use rudder, turn toward good engine and fly back to runway. The reason I like the 3 fuse, is a can put a cam in the center fuse and not have to worry about the prop being in the way, but I'll still have to worry about vibrations.