matchlessaero

Well, here you go. Some time ago, I put a post in this forum about having some "Unlimited" Half-A pylon racing. There was a lot of disagreement about how to do it, but everyone seemed to think it at least was an interesting idea.

With all that in mind, I have designed and begun construction on my "Unlimited" Half-A pylon Racer called the Caliente (Spanish for HOT).

Here are the specs:
High aspect ratio(read long and skinny) foam core 36" span wing. 160 square inches (easily reduced or increased, I plan to build a couple different wings to test). Airfoil is a special 6%.
Two channels pushing a the horizontal on a T-Tail, and inboard ailerons on the wing.
Skinny, round fuselage.
Modified .049 Combat motor (essentially a specially modified AME).
All up weight of 10-11 oz's.

So far, I have already cut the cores, built one wing, and began figuring out the motor and fuel system.
I don't have a digital camera, but I will post some pics of it when it is done.

A pic of the plans is below.

I hope ya'll like it.

edh13

My Feedback: (9)

Why go thru all the work? Just start with any speed 400 pylon plane, throw a firewall in it and go.

Jeff Leavitt

Matchless,

Lookin' good dude! Looks like you have enough room under the CG for the tank. That will keep the flight characteristics[?] the same all through the flight. You have a long enough nose so you won't have an aft CG problem. wing and tail shapes are good looking. I like T tails... This one should fly great. My racing buddy flew his SOKOL fuse with a 200" wing on it last week and he claims it's the best flying racer he's flown. (he has about six) And, the Sokol is a T tail....... keep us posted. I'm interested in how you'll do the T tail and the round fuse. I have a fuse for a Sliver with my 200" wing going together now, and that fuse is pretty skinny. It will be interesting to see how the balsa fuse, and the glass one will compare in speed. I'm anxious to see how it turns out. Best Regards, Jeff.....

2fast4u

My Feedback: (5)

Hay Matchless, another sweet looking plane!!

Question.....As far as drag goes, what diff does the size of the fuse make if it is round and tapered at both ends? Sometimes getting the radio in something would be better done with just a bit more room. I have never designed anything, but I have some ideas, and I was just wondering about this issue...??

PAINLESS

My Feedback: (19)

Matchless,
Do you find there to be a speed advantage using a double taper wing? How does that compare to either a tapered leading or trailing edge?

matchlessaero

EDH13, good thought, but I don't usually build kits. I get a lot more satisfaction designing and building the plane entirely from scratch. When you watch your design/plane round pylon number three on lap ten with everyone else behind, it is the best feeling in the world!

Jeff, thanks for the comments! I just finished a T-tailed sport plane that helped me figure out the construction. I build round fuselages by using a lot of tri-stock and then using my razor plane and sandpaper. Interesting idea about the fuel tank under the cg.......
Your Sliver sounds real cool! Post pics when you can!

2fast, I have heard a lot of opinions about how the fuse affects a plane of this size, and the concensus of them all is that the cross sectional area and wetted area of the fuse greatly increases drag greatly as their dimensions increase. I am no aerodynamicist, but this has also been my experience.
I figured out the radio installation in smaller planes such as my 1/4 A pylon racers.

Painless, In my experience, tapered wings are faster than constant chord. I think however that tip shape is probably more important the format of the taper (straight trailing or leading edge or triple tapered)

Time to go skin the second wing for this thing.......

Troy-RCU

My Feedback: (1)

The taper of a wing can adjust the aspect ratio and lift distribution. This would affect the turning abilities of a wing. Airfoil and wing area would have more impact on actual speed. I find that a slightly swept forward MAC or leading edge can improve turns without major risk of tip stalls. This requires a longer nose or lighter tail for a correct CG.
What airfoil did you pick for this wing, thickness too? Does 1/A pylon have any airfoil limitations? At such light wing loadings I would go as thin as possible with a little camber. I have great custom airfoils for S400 pylon and F5D if you're interested.

PAINLESS

My Feedback: (19)

This is a 1/2A plane I scratch built. About 14 oz, 180 sq in wing area, 34" span, norvell .061 on 25% fuel and a 5x3 prop. It has an MH30 airfoil which is used on some speed 400 planes. It does about 80mph.

One interesting thing about it, is it has an incredible glide slope when coming in dead stick, as good as some gliders I've flown, although I'm not sure why. It also turns very tight without losing too much speed.

Unfortunately it was damaged (repairable) by my flying buddy's girlish launch. I'm going to build another with a high wing and v-tail, which will allow overhand launching.

matchlessaero

Hey Painless, good lookin plane. Great idea to build a high wing version. They are so much easier to land and launch (as you found....) Post pictures of your next one.

Troy, good question on the airfoil (and yes, I would love to see what airfoils you have) Previously I have used several of the Martin Hepperle airfoils for FAI and sp400 electrics. I particularly liked the MH 43 (maybe it was the 42). That is the airfoil I used on my previous 1/4A pylon racers.

When I picked the airfoil for this plane, I chose an NACA 64 series airfoil and thinned it to 6%. That is pretty doggone thin!!!!
The thinness makes it very difficult to cut the cores correctly at the tip. I love the shape, but the first flight will tell a lot.

I finished the second wing for my plane today(I built a long and a short wing), and also cut the fuselage sides today. I used a new(for me) method to skin the wings (another suggestion from DickeyBird). After cutting the cores and prepping them and the 1/32" skins, I laid in the fiberglass reinforcements and spar, and coated the skins with polyurethane glue. I was very worried when I placed the skins, because they did not stick! Trusting the instructions, I put the wing back in the beds on my flat surface and weighted the wing.
After letting the wing set for many hours, I was very pleased to pull out a wing that was slightly heavier than my normal building method, but much stiffer- a big plus with a wing this thin.

I plan to frame the fuse up tommorow morning. Maybe I will be lucky enough to have this thing done before next weekend. (not likely)

Troy-RCU

My Feedback: (1)

Ahh, Hepperle foils are good stuff. Your wing is thinner than I thought. 6% is super thin and making a stiff wing can be tough. Most of my stuff is glass, kevlar, carbon vacume bagged over blue foam so I can get away with certain things and keep it light. I built my Cipher wing (pics below) with 1oz kevlar skins and the torsional is amazing. With the carbon tow spar caps and a vertical grain balsa sheerweb I don't have to worry much about flexing.
I have used the Pro-bond glue for sheeting balsa to foam cores before and the great thing about it is that it foams up and makes a tremendous bond to foam. I pre wet the wood a little (poly-u glue reacts to humidity) and watch it foam out the cracks.
This is my Cipher S400 powered. The airfoils are designed by my friend who is a graduate student at MIT. It is 6.4% thick and the wing area is 95sq". The wing came out of the bag weighing 36grams. Whole airplane ready to fly is just a hair under 11oz. I also have a full flying stab on it just for fun, works very well. I haven't been able to blow it off yet from 500ft dives straight down and on the deck at 120mph. Yahoo! I love small planes.

Troy-RCU

My Feedback: (1)

Over head shot.

PylonWorld

Troy,

I'm trying to de-Cipher the Cipher ... Is that a Stinger fuse, or your own?

Troy-RCU

My Feedback: (1)

It is basically a Stinger fuse. We took a splash off of one (I don't sell any) and did some simple changes. I'd like to do one with a molded fin so I could conceal the full flying stab bellcrank.