hllywdb

OK, so this is my next attempt in my never ending search to design and build a more perfectly flying 1/2a plane. Yes, I know there is another plane called the Slipstream, but it's not 1/2a and I like the name.

This time I am using a 12% airfoil at the rib and 14% at the tip. It has about 232 sq inch of wing with more leading edge taper than others I've built, so the wing is only 35" span. I am also using a built up, airfoiled stab. Not sure if that will make it lighter or fly better, but it looks cool and makes me happy. I am aiming for 14 to 15oz, but that is with an NV .074 and full house with 5 servos. I have hit around 16oz with this combo before, so I am hoping to get lighter this time.

Added a video for those just starting this thread

[youtube]http://www.youtube.com/watch?v=-DuFvfKcRuY[/youtube]

rcguy59

My Feedback: (8)

You've got my attention. I have scratched several flying wings for Norvel .074's in the 14-16 oz. range and they perform very nicely indeed. I'm always on the lookout for a new home for one of my Norvels. Will you have plans/drawings available when you're done?

hllywdb

It's not a flying wing, but a nice clean airframe for a .074. I have 3 of them and love the torque and smooth running. I usually run an APC 6.3 X 4, sure do miss the old Cox grey 7 X 3.5. Yes, I do have plans and laser files. I did alter the turtledeck a bit to fit the canopy I have. I also did a 2 piece leading edge. Yes, it's old school, but easy for me to keep straight

hllywdb

Here she is in the bones, starting to take shape. Pushrod tubes run and motor mount blind nuts in. I am using a Great Planes mini super sportster canopy. The old EP kit they used to make. Seemed about right. I am using carbon fiber pushrods to keep the weight down. 1/32 skins and almost everything built up but the rudder.

alcarafa

Looks like you'll end up with a very nice plane, like the lines .
Design is based in pattern planes ?

hllywdb

Thanks Rafa,

It ends up looking like some of the old school pattern planes, but more as a function rather than form. I have scaled down a lot of 60 size planes to 25 and 1/2A size and run into the same issues. If I take a 60 size plane with a 68" wing and reduce it to a 34" wing, it has 1/2 the wingspan, but ends up with only 1/4 of the sq inch. So with only 1/4 the lift, the plane needs to fly quite a bit faster (in proportion to the 60) which then makes it much twitchier to the controls. By giving it a longer tail moment, it smooths it out, along with a single taper wing. I have tried double taper, no taper, etc.. and find a nice tapered leading edge will by design fly much smoother as well as eliminating tip stall when you get slow or at the top of a vertical 8. It also lets me move the CG back, and makes gear instalation and balancing much easier. Once you go with a longer fuselage, you need to make it lighter and more streamlined to keep from losing performace, so in the end it comes out looking like a pattern plane, but will snap roll as quick as a 60 size plane with a more "normal" tail moment.

soarrich

My Feedback: (98)

That was interesting design insight. Thanks

Mr Cox

With that scaling idea the weight will go down by a factor of 2^3=6, so you will have less weight to carry as well.

alcarafa

Thanks for explaining the process , I started flying classic pattern planes in the 70's and like the lines from those birds.

I have build a 1/2 A CURARE and TIPORARE they both fly very nice, still have a well preserved TD .09 .

If you ever consider sharing the plans please let me know, it would be an honor to build one and become a nice housing for my TD.

hllywdb

Yes Mr Cox, the weight goes down in proportion too (depending on our building skills LOL) but it never seems to translate well. At 1/4 the size and weight, my 1/2A planes don't fly the same at 15mph as a 60 size plane does at 60mph. Might have to do with the air molecule size staying constant, so we have different Reynolds numbers, not sure, would take someone smarter than I to explain it. But I have experimented with laminar wings at this size and find they don't translate well either.

Rafa, I'll post the plans for sure, but this plane is designed around the thrust that a Norvel .074 puts out. The wing is a bit large to fly well with a TD. Maybe scaling it back 8% or so, but it wouldn't fly the same way.

Got some covering done over the weekend, it's starting to take shape.

hllywdb

Here are the (Updated Final) plans for Rafa and RCguy, I also have lazer files in Illustrator floating around somewhere. My exacto skills and patience are not what they should be

alcarafa

Txs I really appreciate your contribution, hope I get some free time soon to build her.

rcguy59

My Feedback: (8)

Thanks!

hllywdb

You guys are more than welcome, Rafa, I always liked the Curare and Tippo too. Thought about building a 1/2A Aurora at some point. I think if you moved the canopy forward on this one and trimmed the rudder just a bit you might have a great looking 1/2A Conquest!

alcarafa

Have the plans for a small AURORA - DIRTY BIRDI - TIPO - CURARE- HAMMER & SUPER SPORTER [X(] ... if you get interested on building one.

You'r right about the conquest

Sport_Pilot

Looks like a cross between a classic pattern plane, and a full scale aerobatic plane. I like it!

alcarafa

Here's a world of canopies to chose for this plane.

http://parkflyerplastics.com/cart/in...385653ca6a0a80

hllywdb

Thanks Sport Pilot. I think the tapered wing and long tail moment give it that classic pattern look, but the canopy, turtledeck, and having the thrust, wing, and stab lines so close give it more Extra or SU influence. I don't like too much canopy and turtledeck as it usually ends up neding too much aileron correction in knife edge.

combatpigg

My Feedback: (3)

That really is looking nice! The .074 Norvel with a 7x3 bridges the gap that the 1/2A engines just don't have the ooommph to cover. It sounds like you know what you are looking for in pattern style performance.

hllywdb

Thanks CP, It's not so much that I want true pattern, I just like the plane to actually FLY through the whole manuver, not just be forced through it. I'm finding that I realy like the APC 6.3 X 4 prop on the 74's. It's a combat prop for a 15 that happens to work well on that motor. The 7 X 3 always leaves me wanting more speed. Yep, next one on the table is a GLH with an 8% airfoil for one of my AME .061 engines. I'm sure you may have some great tips for that project too!

I'm finding that I just realy suck at finding a happy medium. I have a nice classic Harley Heritage softail complete with full windshield, large bags, touring seat, etc... but I like it soooo much more since I dropped in the S&S 113 with the 600 lift gear drive cam and the Baker six speed and Rivera pro juice clutch. So it makes sense why I can't fly one of today's pattern planes. "What do you mean you can't put the gear up and haul butt so you can get it into the sweet spot on the tuned pipe?"

But I digress, back to the plane, I'm doing a Coke bottle cowl, have the plug done and a couple test runs. If I had a place to fly this with landing gear, it would be perfect with the motor inverted and get the thrust line up higher. Just don't feel like digging the dirt and hay out of the head after each landing.

Mr Cox

Yes, the APC 6.3x4 is a very nice match for the .074 engine. I have one a Chipmunk and it is a blast, 3500-17500rpm on 10% nitro.
AndyW fixed me up with an adjustable airbleed and that really helps on the low end. Can even run the engine inverted and fully cowled.

hllywdb

Mr Cox, I wish I had your patience and buiding skills. That is a gorgeous plane.

It is getting close now. Tank and radio are in. It seems I underestimated how much lighter the tail would be going built up stab, rudder, and turtledeck. It came out nose heavy. So it seems one of the "lightening holes" in the bottom of the fuselage will now become a battery access hatch Can't bring myself to add weight to a perfectly good, light aircraft.

My pilot isn't quite as statley looking as Mr Cox's, but I have it on good authority that he can fly well!

alcarafa

Looks really cool, the cowl is made out of a coke bottle like you mentioned ?

hllywdb

Thanks Rafa, yes, the cowl is made using a 2 liter plastic coke bottle. I made a mold out of balsa, then pulled the coke bottle over it while heating it with my heat gun. Presto! A custom cowl on the cheap! I saw the idea posted here a while back and thought I would give it a try. The heat will shrink it around the mold.

Andrew

It's looking really good - with the cowl and tinted canopy, the whole plane comes together. I've downloaded the plans for a possible future build.

For consideration on your next project, if you have separate servos for the ailerons, mounting them on their side may help reduce the exposed area. With an extended horn, you might be able to completely bury them and let only the horn be exposed thru a slot in the servo cover.