mclina

I have decided to try my hand at building a SPAD. I am building sort of cross between a Derelict 25 and a Hell on Rails. Here's what I've got so far:

I have cut a 24" long aluminum 1" angle, made a motor mount from a Wal Mart cutting board, and mounted an OS 25LA. I have mounted the throttle servo and elevator servo, as well as the receiver and battery. I am expecting my coroplast delivery from Harbor Sales tomorrow so I can build my wing and tail.

I am planning on building the wing exactly per the Derelict 25 plans, which will be a 36" wingspan, and building a V-tail per the HOR plans. I will probably just use the V-tail as elevator only, but am thinking of using 2 servos and V-tail mixing for some rudder control. I was also thinking of adding landing gear so I wouldn't have to belly land. I already built a set of gear which weighs 3 ounces.

So far, the fuse, engine, and all radio gear, weigh in around 1 pound 5 ounces. I figure with the wing and tail I will be right around 2 pounds. I am not looking for serious combat performance at this point, just something that will be fun to fly.

Any advice or warnings are appreciated. Do you think the 25LA will pull this OK? Would a longer wingspan help? I've bought enough coro to make several planes, so if this one is a flop, I will keep trying.

zertsman

I have no experience with small engines to mean anything.. i did have a FLATBAT with a 25fp on it that did fly and pull off an underhand launch quite well. put it was a little pokey. for combat a trailing streamer has alot of drag. i never got to drag one. i made a PBF out of it.

your fuse looks great, but you may end up moving the tank when you put your wing on and try to balance.. i also would use the V tail for elevator only.. you can always add the other servo later. save the weight for now.

mclina

Thanks for the advice. I should get the wing built in the next day or two, and I'll post some pictures of how it all turns out.

mclina

Did some work tonight....

DLSmith2

Sharp looking SPAD! For a 25LA, I might recommend 15% fuel and maybe a hot plug. You'll find that it may not be greased lightning, but will be loads of fun to fly! I also would not worry about v-tail mixing, (because you won't notice it) unless you need it for ground steering.

mclina

Here it is done. Took all of three days. I decided to put the landing gear on initially, the thought of hand launching a maiden flight scares the crap out of me. Thursday's forecast is the least windy of this week, so I may try to maiden it then.

zertsman

if you wing is flat on the fuse you will have a problem.. you need to shim up the trailing edge of the wing so that it is parallel to the fuse..

you wing looks like it is symmetrical. the distance from the center of the spar to the fuse needs to match the distance from the middle of the TE of the wing to the fuse.

show us a pick looking down the spar. we can see it better.

mclina

Thanks for your help. Here is a shot of the side. So, with a symmetrical wing, the wing centerline should be parallel with the fuse? I can easily shim it up with some coro, or even put my battery below the wing, wrapped in foam and coro. That should make up about 1/2-3/4 of an inch.

Thanks.

MrGreenSpeed

The wing You built will probably work, ok, maybe, and yes it will need the TE shimmed up...... but.......
The flutes of the coro in Your wing are running the wrong way, the wing should measure 10" cord including the ailerons and 36" span.( hard to tell from the pics )
It's a good first attempt but If You build the wing correctly Your chance of success will be much higher.
If all You have is 4mil coro follow the BUHOR wing build instructions using the Derelict numbers.
Good luck on the maiden flight.

Jeff

mclina

Yeah, I know my flutes are going the wrong way. I must have mixed up my dimensions when I ordered my coro. I figured I'd try it anyway, and see how it goes. I am going to order some 2 mil coro and build a better wing.

The wing is actually a bit deeper than 10". I used a 24"x36" piece of coro, untrimmed. Including the ailerons, the wing is probably 13" deep.

I love how the whole airframe took about 1 hour to build and cost about $8. Even if it doesn't get off the ground, it wasn't a waste.

I have shimmed the TE, and I'll let you all know how the maiden goes in a couple days.

Thanks for all the help.

mclina

Well it turned out to be a beautiful day today, so I brought this thing to the field at lunchtime. The engine was brand new, so I broke it in on the bench. I ran two tanks through it at 1/2 turn rich, and by the end of the second tank it was idling nicely. Full throttle on the bench, 4 ounce tank, the thing ran for just over ten minutes.

It was a bit breezy, so not many people flying today, but a few spectators. I got it running, set it on the ground, and gave just a little throttle to see how straight it tracked. It veered to the right a bit, so I adjusted the landing gear to compensate. Then I carried it to the flight line.

I pointed it into the wind, slowly gave it full throttle, and it took right off. It climbed nicely, and once I got it above the trees I started circling the pattern. It was pretty touchy in the air, definitely too much aileron throw, but with a little practice I was able to get it to fly pretty well. It rolled very nicely, but didn't loop very well. Probably not enough elevator throw.

After about 5 minutes of flying around, mostly under control [], I decided to try and land it. It is not a floater. My first landing was pretty hard on it's nose. Broke the prop and the high speed needle valve bracket broke.

I zip-tied the high speed needle valve to the engine mount, to keep it out of the new prop, refueled, and started her back up. This time, i could not get it to track straight enough for a ground launch, so I had a guy give it a toss for me.

This time, it just didn't want to fly. After the initial nose-up, I pointed it level to gain speed. The ailerons started to respond, but then I pitched it up and stalled it, and it went into the field.

This time the engine mount broke, so I was done for the day, but nothing expensive was damaged.

The wing and fuselage are undamaged, but I think I will build a better wing, using a proven wing design, before I make another attempt at flight. All in all, it was a fun experiment, and it gave the guys at the field a bit of a show.

zertsman

how is your wing held on.. if using rubberbands or zip ties.. when you crash, recheck your cg before you launch.. the wing can shift thrwoing the cg way off. trust me.. i have to keep reminging myself of this... done it more than twice..

if you are using screws.. make sure the holes in the coro dont' get slotted.. or break off a screw.. takes a sec to check the cg before you fire it up.

i think it's a nice looking plane.. keep it light and have a blast.

mclina

I put machine screws poking out of the fuselage on either side of the wing, and used 12 rubber bands to hold it on.

It did sure act like the CG had changed, but the wing, battery, and landing gear locations definitely did not move from one flight to the next. I will definitely re-check my CG before every flight from now on.

Thanks

TruBlu02

Looks like a cool start man. Sorry about the rough first day though. I definately like the looks of your plane as well. I would not worry to much about the flute direction with the 4-mil. I know the general consesus here about flute direction but one of my planes has a wing with Spanwise flutes and it has hundreds of flights on it. The only problem with the spanwise flutes making a smooth LE. Have fun with your design. I am alwas tinkering with my SPADS trying new thing with them. Some times it works, sometimes I end up in front of the bandsaw again making a new Poly engine mount.

mclina

Thanks. I was curious about the flute direction myself, this wing seemed plenty rigid, and with the spanwise flutes, you don't need to glue a separate piece for the ailerons.

I just printed out the wing design for the Defender 25, which uses 24" x 36" 4 mm coro, with 36" flutes. Since I have the materials already, this is the next wing I am going to try out.

A6Ordie

chord wise flutes give you a better airfoil. As long as you have a decent shaped airfoil then your good to go no matter which way you run the flutes. It's just easier to get that airfoil with chord wise over span wise. You'll see when you build another wing You can use some dowel to give you a nice leading edge shape too.

Good Luck,

MrGreenSpeed

Congrats on a successful maiden.
Sorry flight 2 didn't work as well.
Making a wing jig is pretty much necessary to get 4mil to behave,
You'll find that You have to score the LE really really well to get it to fold with the flutes cord wise but it's worth the trouble.
I've used a dremal router with an 1/8 bit 3mil deep to make 4mil fold easier.
Good luck.
Eagerly waiting for pic of the next wing.
Jeff

huck1199

Mclina

I like spanwise flutes because I can make a nice airfoil (flat bottom) and it gives nice lateral strenght. I add a couple of pics; hope they come up here. Looking at the leading edge you can see that the bottom fold has three flutes cut at the LE. Along the top there are three more spaced out cut flutes. This wing has survived a few crashes. I used a few pink foam shapes in the leading edge to support it a little better. I can do mild areobatics with this flat wing mounted flush on a downspout fuse.

zertsman

i have a buhor wing and a RNAF wing and some symmetrical wings all with the flutes going cord wise. gives the best smooth curve without all those pumps.. yours will fly fine, but will not be as smooth on top. when you bend coro parallel to the flutes.. some of the flutes crush.. you can't help it. every crushed flute will make a ridge in your wing.. as in your pic..

mclina

Well, here's my second wing attempt. I built the wing from the SPAD "Defender" plan. Flat bottom and a much cleaner leading edge. Without the landing gear, I had to put the battery pack on the leading edge of the wing to balance, so I put the gear back on. I really do prefer ground launches, and I am still thinking about putting a second servo in the tail and using V-tail mixing so I can steer a little bit on the ground.

I will try to fly it like it is, but the weather is not looking good for the weekend, and next week is Thanksgiving. Maybe I will get to admire this one for a few days before I drive it into the dirt.

My other improvement was to mount the throttle servo up above the cutting board mount. Last time I mounted the servo into the motor mount. I didn't like the fact that on a belly landing, the servo was the first thing to hit the ground.

mclina

As if this RC hobby wasn't already addictive enough, SPAD's take it to a whole new level.

I am off work today, and it's too windy to fly. I decided to put together a Gnat. I have enough servos lying around to make this a "plug and play" airplane. All I'll have to do is transfer the engine pod from my other SPAD, and my RX, and I have a whole new plane to fly.

MrGreenSpeed

Neeto Mosquito, I mean Gnat [8D]

You'll have fun with that if Your reflexes are up to it.
Jeff

mclina

I added a little decoration to it. Very original, huh?

kbear

Your going to like that new wing allot. I've used that kind before and they fly well. Good luck.

mclina

Just a final report on this thread. The new wing design did the trick. I flew it yesterday, and it is awesome. I had a helper toss it for the first flight, and it climbed great (I did away with the landing gear). It took a couple of clicks of down elevator and maybe 1-2 clicks of right aileron trim to fly perfectly. The LA25 flies it very fast and it climbs vertically really far. This was without a streamer - I'm sure that will drag it down a bit. It rolls and loops great, and it floats in for landings really well.

On my second flight, I launched it myself. I held the TX in my left hand and gave it full throttle, and held it just behind the wing with my right hand. A very easy toss got it climbing.

Thanks for all of your advice. I'm definitely hooked.