New design "Trance"

[threcixty]

Hey all. After not having access to my composite supplies for six months, I got bored and decided to design a RES 2 meter. After building this stupid thing, I have gained the utmost respect for anyone that builds with balsa. Especially when it is a new design. I can take blocks of wood and foam to produce a new sailplane of this size from start to finish in about a month of working evenings and weekends. This includes plugs, molds, templates, bagging, laying up, etc. This balsa and spruce plane has taken me about 2.5 months of weekends. You guys are crazy! :D Anyways, just wanted to show off the new plane and see whatcha all think.. I am more of a DLG/slope kinda guy and this is the first plane I have designed without ailerons. Happy Holidays!

Name: Trance. Span: 78.5 Wing area: about 490" Weight with radio equipment minus the tail covering: 20.5oz. (I'm waiting to figure out how I want to do the linkage back there.) Airfoils are Drela based and the structure is all balsa/spruce with fiberglassed balsa fuse and molded carbon poly braces. The tailboom is an Orlimar 49gm driver shaft cut and sanded and the plane balances at about 35%mac without nose weight. Thanks for looking!
Jim

[ZAPPA FAN]

nice blue

[seanpcola]

threcixty, that is sweet! I wanna hear more. Flown yet?

ZAPPA FAN: or is that a REAL poncho?

[threcixty]

Sean, Havent flown it yet, just finishing it up.. finally.... I am trying to figure out how to make an efficient linkage for the Vtail so that I can use some little futaba 3108's for the V as to not have to add tailweight. I like my planes very neutrally stable. Funny seeing where you are at. I bought all of the balsa for this in Pensacola at Radio South. I was flying a run down there and had an 8 hour layover for a week straight and decided to find a hobby shop. Anyways, decided I needed a project, so I bought about $100 worth of contest balsa and spent a few days tweaking the Drela airfoils on Profili. I figure Dr. Drela has no idea what he is doing with aerodynamics, so I might as well add my own flavor to it! I should have it done for next weekend, and if I can find a field somewhere around here and a highstart, I will let you know how it flys!

[fly1milehi]

Very Nice Design work and building!
What is the covering? Also did you add a layer of fiberglass to the fuselage pod before painting or is it primer and paint directly over the wood?

Greg

[threcixty]

Very Nice Design work and building!
What is the covering? Also did you add a layer of fiberglass to the fuselage pod before painting or is it primer and paint directly over the wood?

Greg

Greg.. 2 oz glass, 3m77'd and wet out/blotted. When that cured, I added a layer of very cabosiled epoxy to the pod and then sanded, primed, sanded, primed, etc. I never fiberglassed a fuse before, so I figured it would be like making a fuse plug. Surprisingly, after 1500 grit and polishing, it turned out like a mirror. Oh yea.. The paint changes color from blue to purple to green depending on light.

[fly1milehi]

Sweet!! I thought that looked like camelion or color shift paint!
Looking forward to hearing you flight reports too
greg

[dephela]

I can't quite catch the name on the beer bottle~!

[threcixty]

I can't quite catch the name on the beer bottle~!
Not the same as in my avitar, but Amberbock is the best you can find down here in the south. I am going to start a new web page called "Pilots against relocation." Damn, I miss the west!
btw.. Any bright ideas or pictures for making Vtail linkages? I was thinking something like a torque rod for ailerons with the end bent to compensate for the V angle. Maybe use a ball link or something like that?

[dephela]

Ball-links work well, take a peek at just about any moldie with a V.

Bummer about the brew.

[Wing-span]

Does this help?

[threcixty]

Ok, I feel like an idiot now. That is the simplest looking linkage! Thanks for the help.. I like it!

[Wing-span]

The plane is nearly finished. How much of a scratch build is it? I mean did you design the wing section or use a tried and tested profile?

BTW the Trance looks fantastic.

[threcixty]

Even closer to finished now that i have an idea how to do the linkages. As for the design, it is as original as I can keep it. I havent built many kits before.. An OlyII like 15 years ago, a few Skeeters like 14 years ago, and the only scratch build from plans was a Micro Spirit by Paul Carlson whenever that came out. The thing about these was how straight line/ blocky they looked. I like composite because it offers more freedom of what you can make. This design consisted of finding an airfoil that would perform on paper for the RE I was after at different chords along the wing and then to draw panels that looked ok after that. I am guessing on spar sizing and sheeting. If there is error, it should be on the overbuilt side. As a note to letting a design go where it wants to, look at the wing tip. It was supposed to have a straight taper trailing edge with an eliptical taper leading edge. Profili screwed up the spar location on the tip ribs (about 1/8" thick top-bottom) and the ribs are balsa/liteply sandwich. Since I was feeling lazy, I tried it out and decided it looked pretty cool this way. Go figure. The design process is really fun as you get to engineer out problems along the way and the end product doesn't look too much like other planes out there. It is way too much work.. Atleast on a built up plane.

[Wing-span]

Well I must say you have done a fantastic job. It will be great to see this thing in the air. Hope you catch many thermals with it.

[threcixty]

Thankyou! It has been an interesting project. Waaaay to time consuming. I remember bitchin about paying $50 for an OlyII kit because it cost me 2 weeks of mowing lawns. What a bargain! Ill probably do what I have done with all of my thermal planes.. Thermal it for a day, get bored, try to DS it. :D

[threcixty]

Well, finally got some decent weather here in Birmingham, so I took the plane out for a few handlaunches! It flew pretty well, needing about .25 oz of nose weight. The thing that gets me is how much roll authority the Vtail has! I have said it before, but 90 degree V's work better then 110-120's. The long tail moment further reduces adverse roll and the tail area is pretty generous. I was able to get a 2 minute flight more or less without going above 25 feet and the spoilerons work really well too! Now I just need to find a bigger field and a highstart so I can really see how she does. Thanks again for the ideas on the linkages, and if anyone flies thermal down in AL, drop me a line!
Some completed pics with my pylon racer alongside...
Jim

[Wing-span]

Well done. The Trance is entrancing!

2 mins from a handlaunch is a fantastic time by the way.

[fly1milehi]

Jim,
What is the total all up weight of your Trance? Intersting comment about the v-tail angle as well.. I know popular opinion says 110 - 100 ° but making it at 90° does seem like it would increase the rudder's effectivness. What is the overal length and the tail moment from the wing TE to the Vtail LE?
Greg

[threcixty]

The 2 minute flight was thermal enhanced, but it did seem to glide fairly flat. As for the length, I will have to measure when I get home tonight. The way I figure doing 90 degree V's is this: When you are after an efficient thermal plane, the time when you want the least amount of drag is when searching or thermaling. With a 90 degree V, less drag is required to produce yaw and then roll, which is the control you use most. Do you use elevator control when thermaling or searching all that much? Probably not. The time to use elevator is when setting up for and landing. A little extra drag from elevator deflection seems acceptable here. It is all about compromise. I also try to build my tails fairly large, either cruciform or V tails. In doing this, I can move the cg farther aft and maintain stability, but at higher speeds, the tail can produce enough downforce without stalling as in that little pylon racer or some of my dser's. Keeping the elevons large at the root and small at the tip, while using moderate sweep in the hinge makes the elevator more then effective enough and still provides really smooth yaw/roll control. My .02 anyways!
Jim

[FrogChief]

VERY pretty airplane...I may of missed it, but what airfoil are you going with on it???

[threcixty]

Jim,
What is the total all up weight of your Trance? Intersting comment about the v-tail angle as well.. I know popular opinion says 110 - 100 ° but making it at 90° does seem like it would increase the rudder's effectivness. What is the overal length and the tail moment from the wing TE to the Vtail LE?
Greg
The all up weight is 24oz, the total length is 47" and the tail moment from the wing t.e. to the tail l.e. is 24.5. It could have been lighter, but the golf driver shaft tailboom is a little heavier then most. What can I say except I am lazy and cheap, and the shaft was sitting in my room looking for a plane!
The airfoils are very slightly modified ag45-47 series. Anybody have a highstart or some surgical tubing they want to sell? I sold my winch for $20 a few months ago :(
Jim

[threcixty]

Dumb question: Is the wing area directly on top of the fuselage counted as total wing area?

[grouch]

That is how a sailplane should look! Nice design.

[fly1milehi]

I would bet that most manufacturers include the wing area over the fuselage even though it clearly isnt part of the functioning wing profile. I would bet the engineers among us have either a formula for calculating the area "blanked" by the fuselage or some other criteria for the lost effeciency around the fuse/wing intersection

Greg

[Wing-span]

I'm guessing its not counted. Thats possibly why some wings are pylon mounted to eek out the maximum flying surface area.

[threcixty]

That is what I was thinking. Well, I found some 3/8" latex tubing at Lowes of all places, so Im going to try it off a small highstart today. I need to get a real wingrod soon, but the musicwire one should work for today.
Jim

[threcixty]

Got to try it out on a homemade highstart today.. Lowes actually has some 3/8"od 3/32 wall surgical tubing! I used 30 feet of that and 150 feet of line. I found a field out here that was plowed for new housing. It was pretty large, but full of rocks and small brush. I found out that the wings are WAY overbuilt, as there was no flex at all even when I stretched the highstart as far as it would go. The roll control is about as good as my aileron DLG. Very quick with instant roll. I need to tune the elevons, as I think there is more up then down so the plane pitches up a little bit. I was able to eek 3 ten minute flights out of it (in a row!) so I guess it works well. Flys a little fast, but I can slow down well in the turns. The small tips will tend to drop a wing a little if it gets too slow in a tight turn, but there is no sign of starting a spin. It just drops a tip a foot or two and continues flying. This plane seems pretty clean and accelerates really well, and retains energy too. I was able to dive down to about 50 feet and get 7 loops out of it before I had to stop. Spoilerons work pretty well at rolling the plane. Too bad you cant use em for RES stuff. Anyways, I am pretty happy with it for the moment. If anyone knows of a field in Alabama without rocks and trees and stuff, please drop me a line. I would like to fly without having to catch my plane between scrub brush. Chiggers suck too!

[Wing-span]

Spoilerons? Can you operate each spoiler inderpendantly?

[threcixty]

I hooked up the spoiler servos to the flap channels and then used butterfly for spoiler operation and flaperon mix on a 5 point to make the left or right spoiler open a little at the end of the elevon travel. There is a run on sentence for ya!