Thread Tools
Oct 03, 2011, 08:12 AM
High Altitude Flyer
viking60's Avatar

DANCER II continues to perform very well!


DANCER II continues to be my favorite trainer aircraft for introducing new RC pilots to the sport.

Just last Saturday I had a friend out for his first flight experience, and he was flying it with no problems within a few minutes of coaching. (We were flying the polyhedral under-cambered wing for this introductory flight; I launched & trimmed the aircraft, then turned the transmitter over to him. When the battery was running down later, I took over & flew it in to a hand-catch landing.)

With the option of interchangeable wings, the DANCER II design variant is a versatile performer; and with the pusher motor configuration, the motor & prop are nicely out of harm's way. It's a durable 'Fly Anywhere, Land Anywhere" type of design that's fairly simple to build & fly.

VIKING
Sign up now
to remove ads between posts
Oct 03, 2011, 09:35 AM
High Altitude Flyer
viking60's Avatar
Here are a couple of photos of DANCER II with two of the wings which I fly on it now. (The under-cambered wing has more trim color on it now.)

I'm flying a GWS 6050 SF prop on it now with a 2S 900 mAH battery, which gives more than enough reserve capability as far as speed and penetration to deal with higher winds. For most flying with the under-cambered wing with this prop mounted, we're flying at just above half-throttle.

The KF3P variant wing loves the higher speed capabilities with this prop!

VIKING
Last edited by viking60; Oct 03, 2011 at 09:59 AM.
Oct 10, 2011, 04:35 PM
High Altitude Flyer
viking60's Avatar

Switching from single servo to dual servos for ailerons


Friends,

I just did a quick upgrade on the 59.5" span MH32/KF3P wing. I've installed a second 9 gram aileron servo just alongside the original single servo. This allows using the same control links and horns as were used with the single servo setup.

With the dual aileron servos, I can now set up the transmitter to use flaperon or spoileron control functions while landing, can adjust for optimum aileron differential travel, and can now also experiment with fine-tuning of the airfoil camber quickly from the transmitter.

I'll be test flying the enhanced control capabilities on two existing fuselages before building out a new fuselage; I'll post test flight progress reports here.

VIKING
Last edited by viking60; Oct 13, 2011 at 07:28 AM.
Oct 10, 2011, 10:25 PM
fix-it-up chappie
tolladay's Avatar
Bruce,

I'm looking forward to anything you discover about messing with the chamber. It should be interesting.
Oct 12, 2011, 11:34 AM
High Altitude Flyer
viking60's Avatar

DANCER Sport Flyer fuselage being designed


While the 59.5" wing flew very well when mounted on the venerable PT Electric fuselage in the test flight, the fuselage is simply far heavier than is necessary (or ideal.) But besides handling well as a replacement wing, I was very happy with how the wing with it's single internal 1 meter long tubular CF spar dealt with the aircraft's total flying weight of ~40 ounces. The wing structure build is definitely up to the task, handling loops & rolls nicely.

These MH32/KF3P wings (59.5" and 62") perform superbly for gliding and slope flying tasks when mounted on the DANCER III slim fuselage with it's folding prop. My next project now is to design & build a new 'sport flying' fuselage which is designed for solidly mounting gear for wheels, skis, or floats which will also have room inside to carry a variety of batteries & other gear when desired.

VIKING
Oct 12, 2011, 01:11 PM
rcflyer
Quote:
Originally Posted by viking60 View Post
While the 59.5" wing flew very well when mounted on the venerable PT Electric fuselage in the test flight, the fuselage is simply far heavier than is necessary (or ideal.) But besides handling well as a replacement wing, I was very happy with how the wing with it's single internal 1 meter long tubular CF spar dealt with the aircraft's total flying weight of ~40 ounces. The wing structure build is definitely up to the task, handling loops & rolls nicely.

These MH32/KF3P wings (59.5" and 62") perform superbly for gliding and slope flying tasks when mounted on the DANCER III slim fuselage with it's folding prop. My next project now is to design & build a new 'sport flying' fuselage which is designed for solidly mounting gear for wheels, skis, or floats which will also have room inside to carry a variety of batteries & other gear when desired.

VIKING
I'm looking forward to seeing your final designs & pics
Oct 14, 2011, 06:05 PM
High Altitude Flyer
viking60's Avatar

60" DANCER series Sport Fuselage


Friends,

Here's a quick look at how I'm building out the prototype 'Sport Fuselage".

I considered a few options as to how to do this, and decided that, since I have pieces left over from previous slope ship building projects, I would build another solid EPP foam fuselage. The cross-section in the area under the wing is 2-7/16" wide by 2-3/4" high - (the piece remaining from a previous project which I started with just happened to be large enough to cut it to these dimensions.) Overall length of the fuselage foam core is 33-1/4".

The EPP, as shown, weighs only 1-7/8 ounces. It's tough & resilient material, allowing components to be inset into the foam. I'll inset birch ply plates for the firewall, landing gear mounting surfaces, and wing mounts.

I'm using 6mm Depron for the tail group; there's 5/8 ounces of tail group parts after hinging, before mounting. I've done some sanding to shape the edges of the vertical stabilizer and rudder; I'll also shape the leading & trailing edges of the horizontal stabilizer and elevator. The idea is to minimize drag in the tail group with only a modest investment of time & effort. I'll also likely do some heat-tempering of the sanded areas to increase their durability before everything is assembled.

I will be shaping the fuselage further, carving & sanding away some more foam. Once the motor mount firewall & landing gear mounting ply plates are installed, the entire fuselage will be covered with a tough iron-on covering film. This will add the final rigidity to the foam and keep it from absorbing dirt or moisture. Goldberg Ultracote and clear Doculam material adhere well to bare EPP foam at low application temperatures, so I'll likely use them again.

I'll post further updates and more photos as this project progresses.

A built-out fuselage of somewhat similar dimensions made from sheet foam with internal structure to provide the required strength could also be built.

I still have the EPP material on hand & the band saw to do the initial shaping quickly & accurately, so I'm inclined to do a quick & simple fuselage build with it. I know from many previous builds just how tough and resilient a solid EPP fuselage can be.

VIKING
Last edited by viking60; Oct 15, 2011 at 09:11 AM.
Oct 19, 2011, 09:11 AM
High Altitude Flyer
viking60's Avatar
[I posted this comment in another discussion thread:]

There are many ways of implementing KF variant stepped discontinuities into the design of miniature aircraft wings. There are 'quick & dirty' ways of layering foam sheets which result in great fun fliers. These builders are simply enjoying flying what they build. The variety is great, and the creativity displayed is to be applauded.... the idea is that lots of flyers are having an incredible amount of fun doing it!

I've focused some of my foamie wing design & construction work on lower profile step implementations than those commonly being used- ways of designing & building foamie wings which exhibit minimal drag, good glide efficiency, precise control response and very good stability.

The slope flying report on DANCER III with the 59" MH32/KF3P wing may be of interest; (it can be found in post #35, on page 3 of this Dancer thread.). Wind speeds were recorded at up to 29 MPH while I was checking before launch, and I was flying without any power / motor run in slope winds of this velocity (& gusting stronger at times) at a wing loading of only 5.7 ounces per square foot.


Dickeroo Commented:

VIKING...

I read your experiences with KFm3 DANCER III and it was thrilling to hear how well she flew in those wind conditions. You've really refined the step applications to a fine art. And, you have contributed so much to the development of the KFm Family of Airfoils with your experimental approach to refining the different configurations.

– Dick


Dick,

Thanks much for the kind words!


Jackerbes asked:

If you had to guess at it, as generalization, what kind of winds would you want to fly the Dancer III as a slope glider without power on that slope?

Like if you wanted to have wind enough and lift enough off of the slope face to make reliable turns and transits across the slope face and to recover altitude?

I know it is a very variable thing with the geography and even the person flying, I'm just try to get a general idea. I'm getting more interested in gliders and am trying to get a feel for the geography and conditions for slope flying.

The Dancer III's performance in slope gliding, as a motor glider with the motor simply not used, is a beautiful thing! As a guy that is somewhat enamored by having a motor to "rescue a glider from stupidity and the evils of nature" a Dancer III will get built this winter for sure.

Jack


I replied:

Jack,

As you mentioned, the variability of the geography / topography of a given slope really is a major factor. Dave Thornburg, in his "Old Buzzard's Soaring Book" devotes chapters 7 & 8 to this topic. (The book is one of the best I know of about flying gliders; Dave was the creator of the fine "Bird Of Time" glider, & a top competitor in his time. At one time this book was available through the AMA book store.)

At a wing loading of 5.7 Oz, the DANCER III will glide well in light lift. Maybe 5 to 6 MPH will be adequate to stay up on a nicely shaped slope and have fun flying without having to work at it much at all. (It'll cruise across Antelope Flats at 20 feet off the ground for a couple of hundred yards in calm warm air and barely loose any altitude when it's trimmed out right, so it doesn't need a lot of 'up' component to the air to keep flying.)

The fact that it will continue to penetrate, handle cleanly and smoothly, and can stay out in front of the slope in winds up to & over 30 MPH without adding any additional ballast is what is really significant. That says to me in no uncertain terms that the wing and fuselage design are aerodynamically clean enough, that the drag from all of the various design aspects has been minimized fairly effectively.

Flying cycling lifting / sinking air on a slope before the big winds come up

I also definitely agree that having the motor with the folding prop as a backup adds a lot of options when heading out to the slope. On many mostly sunny to partly cloudy days of inland slope flying, earlier in the day before the strong slope winds build to consistent strength, you'll see waves of 'lift' - cycles of warm air move into the slope face. Each lift cycle may only last for 30 to 45 seconds earlier on a given day, with warm rising air coming across into the slope, rising, and sometimes separating as major bubbles of lifting air. But for every rising warm air mass, there has to also be a following mass of cooler sinking air that's being drawn in to replace that bubble of rising warm air. So you may have a minute or less of 'up' air followed by three to four minutes or more of cooler sinking air (depending upon the rate of the prevailing breezes cycling these air masses into the face of your slope.)

When you're up & flying a lifting air cycle, and the lift dies & you feel the air going a bit cooler as you watch your glider start to struggle to hold altitude, you can power up and punch out well in front of the slope to try to locate the next mass of warmer flyable air. Once you detect the 'bump' from flying into that next cyclic mass of warmer rising air, you can chop the power and explore the extent of the warm air mass, and follow it back to the face of your slope. When the cycle of cool air which follows it moves in and the lift dies out, you can simply power up & punch way out upwind again to find the next mass of warm air. (The pure slope gliders are busily watching your lead, launching & landing, waiting for the next cycle of lift to reach the slope, & then trying to land again as the lift dies before the air goes too cool & they have to end up landing down slope.)

Flying this type of cycling lift / sink air is a bit of magic once you understand what's happening. Once the prevailing winds build to a stronger constant velocity for slope flying, you'll still feel the warmer / cooler masses of air as they move through, and you can watch your aircraft and see the affects which these air temperature variation cycles have upon the handling of your slope ship.

Jackerbes responded:

Wow! What a wonderful reply! A complete slope flying lesson for a new sloper...

I just found that book for sale at Carsten's and ordered it. I needed something like that...

There is so much to learn and so little time and I do love books.

Thanks again,

Jack



Jack,

I ordered my last two copies from Carsten's too- (I couldn't remember their name at the moment until you mentioned it here again.) Thanks!
VIKING
Last edited by viking60; Oct 21, 2011 at 09:26 AM.
Oct 21, 2011, 09:14 AM
High Altitude Flyer
viking60's Avatar
Friends,

here's a direct link to "Old Buzzard's Soaring Book"

http://carstensbookstore.com/oldbusobobyd.html

It has a lot of really good information on both thermal and slope flying; I've loaned out my copy several times... (still have one loaner out there somewhere...)

VIKING
Last edited by viking60; Oct 22, 2011 at 06:57 PM.
Oct 21, 2011, 02:25 PM
High Altitude Flyer
viking60's Avatar

Progress on the Dancer SPORT fuselage


Friends,

Here's a quick look at the progress on the new Dancer Sport fuselage. After installing the ply firewall, landing gear mount plate, and wing mount plates in the fuselage, some excess foam was first carved away with a sharp filet knife. Then the contours were sanded to a round profile.

The main idea is to end up with a fuselage with minimal drag which has the capability of being optionally flow with landing gear for doing ROG takeoffs, fly from skis, and doing touch-n-goes. When flown without the landing gear, it should do well as far as glide efficiency... it has design roots going back into many EPP slope combat ships.

The option of flying it with a folding prop rather than a fixed blade prop is something I had in mind as I shaped the nose area into the round firewall. A rolled sheet lexan conical motor faring may be installed to further clean up the nose.

Folding props dramatically cut down on drag compared to a fixed prop sticking out in the wind.... for doing comparative testing of these wing designs, it's very helpful to eliminate drag wherever possible.

I'll apply a minimum of nylon filament tape in a few key areas before the Oracover covering is ironed on directly over the EPP foam. The result should be a fairly lightweight fuselage that's resilient and durable.

I'll finish the covering, mount the tail group in place, and install the servos & linkages before long. Deciding where to cut the battery bay within the foam fuselage will be one of the final steps.

More soon!

VIKING
Oct 24, 2011, 09:47 AM
High Altitude Flyer
viking60's Avatar

Dancer V 'Sport Fuselage' test flight


Friends,

Yesterday morning I completed the control linkage installation. I then added the velcro for temporarily mounting the battery for initial test flying. I'm using an 1800mAH 3S 35C LiPo battery (from HeadsUPRC.com) for the test flights. The photos below show the aircraft ready to fly (without the landing gear for these first flights.)

Unfortunately, the motor which I had first installed developed problems. I ended up flying three shorter launches, flights, & landings as I adjusted the balance / battery mounting position before the motor problem got bad enough to stop flying. So I brought it back to the hangar to install a different motor.

I've now mounted an EC28PL motor ($12 from BlackdogRC.com) It's drawing 14.5 amps turning the 10x6 folding prop on this 3S battery pack. That's 175 watts of input power, according to the wattmeter. I'll mount the landing gear this morning & get back out for some more test flying later today if all goes as planned.

The photos also give a fair perspective of part of the 'Antelope Flats Aerodrome' where I fly. There's presently an area of lightly groomed short grass prairie that's presently about 600 feet by 400 feet, available for takeoffs & landings of aircraft with (or without) landing gear/ wheels in any direction, depending upon the prevailing wind direction at any given time. It's been cleaned up to be friendly ground for belly-landing gliders, and smooth enough for all of my aircraft with wheels- which is why this new fuselage is designed for mounting landing gear too!

The FUN continues!

VIKING
Last edited by viking60; Oct 24, 2011 at 09:53 AM.
Oct 24, 2011, 04:17 PM
High Altitude Flyer
viking60's Avatar

Flying DANCER 5 with the wheel gear


With the motor replaced, and with the landing gear and 70mm foam wheels mounted, I headed down to the flying site earlier today. Dancer 5 LIKES this EC28PL motor! With a flying weight at 25-3/8 ounces, it now has plenty of power. It'll get off the ground in about 15 feet or less of roll without the flaps. With flaps deployed, it'll be up off the ground in less than 10 feet!

The rudder is very effective during ROG takeoffs, and the aileron response is clean and precise. Roll rate is good, and both inside and outside loops are performed easily. Holding in inverted flight is relatively easy with only very slight forward pressure used on the elevator stick.

But the takeoffs & landings were what I'd wanted to really do a lot of this morning before the winds built up, and that's exactly what I did. I must have done over 25 ROG takeoffs and landings to a full stop on the first battery, & still had good performance from the battery when I swapped it out.

This really is a fine glider wing, and the wing loading is at 6.54 ounces per square foot. On low passes, I could hear the wind whistling past the landing gear wires- a sound that's not there when flying without the gear mounted.
But even with the added drag of the landing gear, on a landing approach DANCER 5 really glides a long ways without loosing much speed or altitude. I had to start doing something like a stall turn in close & low when turning on to final for landing so that it wasn't carrying too much extra speed into the landing, or it would just fly across the aerodrome in ground effect without wanting to settle in on its wheels.

I played with getting the flap total deflection setting on the transmitter right for this aircraft (about 40 degrees down maximum?), then set in the Flap > Elevator mixing (+19%) so that deploying flaps would affect the pitch attitude only minimally or not at all. (There may be a slight variation in response based upon the aircraft's airpeed, but it's very minimal now.) Once it was adjusted right, I could bring in the aircraft with full flaps deployed and have it gliding in at a slow walking speed to touchdown.

With the wing loading still relatively low at around 6.5 ounces, and with the nose-high stance of the aircraft on landing gear, low & slow handling & ground handling is fun & easy when the breezes are modest. When the wind speed picks up it's best to carry a bit more airspeed so that variable gusts don't catch the aircraft in a vulnerable attitude. DANCER 5 handles very cleanly and predictably across the entire speed range, from full throttle to the slow walking speed full flaps landing. It's doing everything I had in mind in designing & building out this Sport fuselage!

I'm getting close to cutting in a battery compartment within the EPP fuselage. That will get the last 'drag generator' within the aircraft, cables & all, under it's own hatch cover so that very little will be hanging out in the wind (other than the servo control horns & CF control rods which are in close to the body just under the wing.... that much for drag I can live with!)

The radio receiver now has a matching hatch cover, and the ESC has only ~1 square inch of it's label area just over the main heat sink which is exposed. Motor &, ESC are all only very moderately warm to the touch upon landing, and this 35C rated battery with only a max ~8C current demand doesn't even think of warming up... so everything seems to be fine as far as heat concerns.

VIKING
Oct 28, 2011, 08:07 AM
High Altitude Flyer
viking60's Avatar

Fresh snow in South Park


Dancer V is flying superbly from snow with skis mounted on it's landing gear. Flying weight is about 29 ounces. The power system is well suited to handling this aircraft's flying weight easily.

(More later.)

VIKING
Nov 25, 2011, 01:46 PM
High Altitude Flyer
viking60's Avatar

Hand Launch Glider: Wing Upgrades


Friends,

I had done work a while back on a Hand Launch Glider fuselage on which I could mount the ~46" span KHm2 & 3 wings. A shoulder separation in my throwing arm motivated me to set aside that project for a time; I'm happy to report that the shoulder is improving, so I'm revisiting this project.

While doing some of the development & flight testing of the Soarbird IV KFm3 wing, I had experimented with removing the upper foam layers from the wingtip areas. The result was significantly reduced drag, and therefore an observably more efficient glide. Since then, I had done the same type of modification to the KFm3 variant wing which I'd first built to fly on DANCER I.

Today, I brought the HLG fuselage down from it's place on the hangar ceiling and charged up it's battery. Then I brought out the ~7.5% thick KFm2 wing, which had not yet had this modification done. The first photo below shows the start of the modification; I use a long thin bladed fillet knife to carve away the excess foam, and to slightly re-contour the shape of the wing tips. I then used the covering iron to heat-shape, temper, and finish-contour the Bluecor foam. The leading edges of these wingtips are fairly well- thinned, and the trailing edges are also thinned nicely.

Next, I hauled out some 3mm thick black depron, and cut two insert panels to convert this into another KFm3 wing. In the process of installing these panels, the primary step which is at about 48% of chord is reduced to only 3mm in depth, and the secondary step at ~70% of chord is also only 3mm deep.

I ironed on some Oracover over the exposed bluecor to do a quick dress-up of the wing tip areas where the excess foam had been removed. The resulting wing after these modifications gained 1/4 ounce of Depron, hot melt glue, and covering, for a flying weight of 7.5 ounces, & a wing loading of 3.5 ounces per square foot.

Weather is a bit nasty with cold gusty winds and a few snow flurries blowing around, so after a brief test-glide, I'm waiting for a better day to do more extensive test flying. I'll post the flight report here when the weather warms up & the winds die down some.

Further details on the HLG fuselage build & setup are on page 1 of this thread.

VIKING
Last edited by viking60; Nov 26, 2011 at 09:03 AM.


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Least drag flying wing or pod and boom for pusher colbourne High Performance 2 Feb 22, 2008 12:25 AM
Sold Supergee pod, boom & wing cores jfruge Aircraft - Sailplanes (FS/W) 4 Jan 23, 2006 07:46 PM
Sold FS Supergee pod, boom & wing core Gliderguy Aircraft - Sailplanes (FS/W) 7 Aug 28, 2005 11:16 PM
High Wing EPP Plane bigryan Parkflyers 13 Apr 24, 2004 10:04 PM
WTB 48" Lazy Bee Wing AirVenture Aircraft - Electric - Airplanes (FS/W) 0 Jul 20, 2003 10:33 PM