combatpigg

My Feedback: (3)

I think this might be the most obvious SWR project that has been overlooked. So far all of the SWR projects have had something exotic [[8D]] featured.....but for once how about a simple deal that is versatile enough for any 1/2A set up and still able to go 90? Patterned roughly after a Q-500 plane. You can take any ordinary 1/2A engine that's in good shape, throw a 4.2x4 prop on it and end up with a little screamer. Now put the little screamer on a plane that doesn't load it down and you end up with something that might put a smile on your face, [well, at least a smirk].
I came up with a couple of observations while measuring stuff up. A 5"x25" wing looks about right. I'm going to make mine 26" along the trailing edge and 25" in front. If I go with MJD's film can balloon tank, the front end can measure about 1 1/2" x 1 1/2" on the outside. A battery would then need to go behind the tank, which makes getting the CG "right" on a short nosed model more difficult. If the front is bumped up to 1 3/4" x 1 3/4", then there is room to cram a battery next to the tank and leave the nose more "Q-500ish". The question is if the bigger front end will look too massive and also be too much drag to make the project worth doing?

forsakenrider

I like the skinny and maybe longer nose idea. Help me out with an airfoil and I will build one!

soarrich

My Feedback: (98)

Why not just 125 sq/in wing and see what gets made. I know I don't want to build a boxy plane, wouldn't the 125 sq/inch wing be enough restriction. I would like to build a small plane that would do a 100 mph with a stock Norvel 1cc motor.

ProBroJoe

Why not an alternate battery location? Say a 300-400 mAh LiPo and a Berg Microstamp RX - can't they take a 2 cell LiPo directly? I don't understand the need to locate battery next to the fuel tank....

I'll tell ya what CP - your idea is somewhat timely... I've been lurking over in the ESPP forum and eying up the Viper... [8D]

combatpigg

My Feedback: (3)

Hi Rich....I'm just thinking out loud. Looking for input and opinions. Of course the sleek approach is the way to go, a big, boxy front end makes no sense. The Q-500 firewall is just big enough to mount the engine. They do have a rule about corner radiuses to control the amount of effort that goes into construction, I don't remember what it is exactly...1/4" radius?
For me, this project will be the first time running a Cyclon on backplate pressure with a bubbleless tank. I'd like to see how the freeflighters do it.....the actual mounting and plumbing layout. I'm sure they have a very neat solution to it.

PBJ, the smallest pack I use is about the size of a 5 cent Chick-O-Stick candy [220 nimh]. It weighs about a little over 1/2 oz. It sure does create an aerodynamic log jam to cram it up front next to the tank. For my plane the MJD tank is a must, so I guess the battery will ride just behind the tank and design the plane just large enough to fit the tank. With a bubbleless tank there is no need to design in room for padding. I'll just use padding to keep the tank still.

MJD

My Feedback: (1)

I wonder how much pressure there is? Might need to add some glass tape to help keep the cap on? I dunno! All the ff'ers I've seen or known (not too many) use bladders.

I think the firewall should be minimum 1.25" or 1.375" square or something like that, how about fundamentally wood construction. Are you planning on mandating sheet wings...? I think yer right on the radius.

I gotta order more of that cool tape I used on those tanks, I'm out now, and it appears to be quite fuelproof.

MJD

combatpigg

My Feedback: (3)

Mandates? [X(]
How can you enforce SWR rules with what "hit men" charge nowadays? [8D]
I think a $7 sheet of 6" wide, 1/4" thick balsa is just too simple to not use in this size range. My LHS had a stack of SIG sheets to sort through and with the help of a scale I picked out a few keepers.
They weigh about 120 grams each and are what you would call "light side of medium" I plan on sinking a 1/8" x 1/4" x 12" pine spar in there on mine.

I hope some of you give this project a whirl and get some fun in return.

iflyg450

I can't wait to see the finised product! I love the way Q500 planes fly. I wish I could find a Lanier Dominator 200 1/2A if anyone has one they want to sell let me know

cncswiss1

can the 4 cells be spread radially around the tank, in the 4 corners of the fuse? with a film can tank there should be some room, whether it's enough room is up for debate and experimentation

forsakenrider

What about a built up 1/32" sheeted wing? Im sure you wouldnt need too many ribs....

combatpigg

My Feedback: (3)

1/32" is too fragile IMO, but if you believe in any idea strongly enough, you can make it work.........

....except in this case .

I tried built up elevators for C/L combat planes many years ago, where you sheet over little ribs. It wasn't worth the effort then, but in a different application with a different pair of hands doing the work, it might be a good idea. Give it a try and report back!

r2champion

I certainly enjoy when the snow arrives at CP's house! Looks like I will soon have a project to tackle!

soarrich

My Feedback: (98)

Wouldn't you be able to put the tank back on the CG and the battery in front of the tank?

combatpigg

My Feedback: (3)

HeyR2C......The beautiful snow part is OK, but I'm afraid to fly and lose the plane in a snow bank.
Time to get out your carving equipment and make a plane, I'd say.
I'm sizing up the onboard equipment now to decide on fuselage dimensions. The wing has been cut out and set aside.

vicman

My Feedback: (10)

Ho Hum[sm=49_49.gif]
Beentherediditgotatrophytoproveit

Not a SWR but certainly a Q500 style 1/2a racer.
Contact BobHH for his QuickShot kit. 85mph with a Black Widow and 91 with a TD .049.[sm=wink_smile.gif]

combatpigg

My Feedback: (3)

Vic, how long is it from the firewall to the very end?
What does it measure from the firewall to the leading edge?
What are the wing dimensions?
I forgot you had that plane under radar surveilance last year. Those are impressive speeds.

forsakenrider

Ok CP, help me out with a freakin airfoil cuz i am terrible (un experienced) with that and I will get on the drawing board.

rainedave

My Feedback: (1)

Nothing at our reedie races seems able to beat Bob's design. But then, I haven't designed a pure pylon model yet.[X(] But, the Sure Shark - a larger, aerobatic model with a thick semi-symmetrical airfoil - did come in second. And I have the trophy to prove that, too.

David

combatpigg

My Feedback: (3)

FSR, it helps to have a couple of tools. A fine line marking pen to draw reference lines and lay out lines with. It is also very handy to buy a very heavy grit [40] sanding belt and fit it to a chunk of 2x4. You will also want to get a 80 grit belt and set it up on a block, too. A razor plane is very handy, but takes practice so you don't gouge the wood. You can get by with just the sanding blocks and a particle mask. You need to work in very good light and know how to use the light to detect flaws. Don't over sand, but if you do you can piece in scrap balsa to hide your mistake. Mark out a "no touch" zone on the high point of your airfoil about an inch wide. I place the high point about 40% of the chord. The rest is simple, just shape the airfoil and don't get carried away with the heavy grit. I use 120 grit on a long sanding block to bring the trailing edge into focus and to shape a fully rounded leading edge, also to sand out the bulk of the scratches. 120 is your final shaping tool. Switch to 220 grit wrapped around a soft sanding block to sand out the visible scratches and to buff the wood. [Uhh, he said "buff the wood", Beavis]
I don't switch to 220 grit until after the ailerons are rigged and hinged. I like to cover the whole works in one shot.
The third photo shows end caps made out of pine to help keep the balsa wood from "cupping". I probably should cut them off and switch to maple, these might be too wimpy.

combatpigg

My Feedback: (3)

Rich, I've never tried a tank on the CG. I might end up with a tank hatch on this one [though it makes the front end much weaker]. I need to be able to switch batteries without disturbing the tank. Some engines, [like a TD on suction] are sensitive to head pressure so a "remote" tank would undoubtedly need backplate pressure to cut down on that 4-2-4 stuff.

MJD

My Feedback: (1)

I think you could only get away with that with a high pressure fuel system - bladder or as CP suggested backplate pressure. These small engines have marginal fuel draw at best and I freak out when a tank is 1/2" farther away than it should be. To me, if the former at the wing LE is hollowed out, the tank area and equipment area above/below the wing are one cavity, and I'll put tank first no matter what then fit all else behind as required. Putting batteries radially around the tank would end up with a big fuselage - the corner space is what's left around about a 1-1/8" circle. I'd put minimal forntal area as priority one and the aesthetics of long noses as a secondary priority to design out as much as possible.

MJD

Larry Driskill

SWR ?

vicman

My Feedback: (10)

Sheet Wing Racer.

rainedave

My Feedback: (1)

cp, great technique. Were you ever into HLG's?

What thickness to chord ratio do you think works best? What is that? 3/16" or 1/4" balsa? What's the chord?

Thanks,
David

forsakenrider

so you are going with a flat bottom wing? I was thinking more of symmetrical, but the sheet wing idea seems easy. My mouse racer is a sheet of basswood i planed down but i have an airfoil to look at and copy.