ME163-e KOMET Powered Glider For Slope & Thermals, Folding Prop

viking60 · Jan 05, 2009, 09:48 AM

The ME163-e Komet is a new powered glider design with a folding propeller in front, and a high glide efficiency wing design. It is built up from Bluecor FFF with an optional EPP lower fuselage. It was designed to roll nicely, loop well, penetrate winds well, and ride thermal lift or slope winds efficiently.

One of it's most unique features is the airfoil profile of the built-up wing, based upon the MH32 airfoil. The result is a very efficient gliding wing that can penetrate winds well, yet is simple to build on a flat surface.

Wingspan is 39-3/4" as shown; overall length is 26-3/8". It uses elevons and rudder as control surfaces. The wing also features eliptical upswept wing tips, and my own variant of a "KFm3 variant" dual top step implementation, with the main step at 50% of chord. Surface mounted turbulator spars are also used, placed at ~15% of chord.

This Komet is designed to be powered with a variety of motors on a front firewall mount, including the 'Blue Wonder' 1500Kv motor and a 10 Amp ESC. My first prototype, just through the first test flight, is flying on a 2S 900 ABF LiPo battery at 10-3/8 ounces. With 2.2 square feet of wing area, that gives a wing loading of less than 5 ounces per square foot.

I chose to use tapered balsa control surfaces to end up with very thin trailing edges to minimize drag, thereby increasing glide efficiency as well as wind penetration at modest wing loadings. The shaping of the forward section of the was given careful consideration, since 50% of a wing's lift is generated by the shape of the front 25% of the wing's airfoil. So a lot of performance can be gained, as far as glide efficiency and wind penetration ability, by carefully shaping the forward section of any wing.

The ME163-e Komet has a full web page of it's own on my web site at:

http://www.stenulson.net/rcflight/komet.htm

Many of the design details, build sequence photos, and the preliminary rough plan are all in one place there.

The build is in it's finishing stages after a very successful first flight (in very frigid zero degree conditions!)

More details will be added soon!

VIKING

viking60 · Jan 05, 2009, 09:49 AM

Here is the top view of the origional Me163b, and the rough plan drawing which I used to start this build. The plans will be updated with more detail when time allows.

VIKING

viking60 · Jan 05, 2009, 09:51 AM

Here's a couple of the early build sequence steps; this Komet was designed as I built this prototype, starting from the rough plan and laying it out directly on a sheet of Bluecor PP.

VIKING

Rolland Benson · Jan 05, 2009, 04:02 PM

Viking

Looks like this is one fine plane. I will be hanging around to see how the flight reports do. Although not zero here I was out today and I know what you mean about the fingers getting cold fast.

Rolland

Rolland Benson · Jan 05, 2009, 04:05 PM

Viking

I am curious about the rudder function. I have never built a wing with a working rudder. What is the advantage of having a working rudder with elevons?

Rolland

viking60 · Jan 05, 2009, 04:11 PM

Once the 4 main Bluecor pieces were cut out, I started laying in the lower wing panel's pair of CF rod cap spars. these were inset flush with the surface, directly above / below each other, into shallow slots that I melted with an adjustable temperature soldering iron set to a low temperature.

The CF rod spars were then glued in place with foam-safe CyA glue.

Next, the Vertical stabilizer was also stiffened with another pair of 1mm CF rods.

Once these CF rods were installed, the upper fuselage panel was epoxied in place.

MYHELIGUY · Jan 05, 2009, 04:13 PM

viking60
now this is really a nice interesting build.does this kfm3 assist in slow flight?

viking60 · Jan 05, 2009, 04:25 PM

Quote:

Originally Posted by Rolland Benson

Viking

I am curious about the rudder function. I have never built a wing with a working rudder. What is the advantage of having a working rudder with elevons?

Rolland

Rolland- good question! For slope flying purposes & park flying, the rudder would not be needed; a fixedvertical stabilizer could be built. A 'bank-n-yank' style of flying is used then, which works great for slope flying and for fun flying.

I like to chase thermals, and I also had that task in mind when designing this Komet... this is where the rudder can come in handy, to keep within a tighter patch of rising air without having to bank steeply. I actually fly a lot of opposite aileron (elevon) to keep the rudder turns flattened out, & am thereby able to keep climbing in light lift. It's just what I decided to do when building the first prototype; I'm sure it will thermal almost as well in average lift without a rudder.

A rudder does need a certain amount of forward vertical fuselage structure to work against to be effective; from my test flight last evening, I'll say that the present layout allows the rudder to be nicely effective.

The rudder would not have to be as deep as I made it, but I was thinking that a large rudder with small deflections produces far less drag than a small rudder and large deflections. High efficiency gliding is the core of the performance envelope for this Komet... I do not know yet where the edges of that performance envelope will reach.

VIKING

viking60 · Jan 05, 2009, 04:29 PM

Quote:

Originally Posted by MYHELIGUY

viking60
now this is really a nice interesting build.does this kfm3 assist in slow flight?

From my initial launches and landing approaches, I'll have to say a very positive YES... it has excellent low speed handling, and can be set down in almost a full mush stall without showing any tendancy of dropping off, from what I've experienced so far. The KFm3 structures are responsible for some of this; some comes from the eliptically upswept wing tips, while there is also a contribution from the top surface forward turbulator spar... all work together to provide good stability across a wide speed range. More flying will allow me to elaborate further on this.

VIKING

viking60 · Jan 05, 2009, 06:54 PM

These photos show the top wing panels being set in place after being trial-fitted; a bit of sanding gets everything matching up. Photo captions tell more of the story.

VIKING

Zaurak3 · Jan 05, 2009, 07:15 PM

Happy to see it worked out for you, Viking. I hope you have as many enjoyable flights as I have had with mine. Dr. Lippisch deserves the bulk of the credit for this sweet flyer!

viking60 · Jan 05, 2009, 07:44 PM

Z,

Yes, my approach to building out this ME163-e variant is working out very well!
There are a lot of design elements employed here that Dr. L may never have used.... a radically different airfoil, different wing tips, an implementation of the KF step elements, a different fuselage shape, and a different vertical stabilizer profile than what the ME163b used.

He'd certainly smile as he recognized the silhouette as it passed overhead.

And of course, once we start working with foam and thin CF rod stressed spar structures, we're firmly into the 21st century era of miniature aircraft design.

The photos below show details of how the second pair of eliptical spar caps are placed to finish giving this wing structure it's incredible rigidity... when you consider that there's less than four hundredths of an ounce of CF in this set of spars, you can truely appreciate the value of these materials. The KOMET web page has more of the construction details:

http://www.stenulson.net/rcflight/komet.htm

VIKING

viking60 · Jan 05, 2009, 07:58 PM

Leading edge and trailing edge shaping is critical to achieving the optimum glide efficiency performance.

I start by carving away excess foam with a new razor knife blade. Sanding is useful in some areas. Then I bring out the covering iron, set carefully to a temperature where it will heat, compress, and temper the foam over a bit of time. If the iron is set too hot, it will ment the foam, and you'll find it sticking to the iron's surface.

I actually end up with a bit of sanding, removing any high spots from my desired finished profile.

VIKING

Dickeroo · Jan 05, 2009, 08:03 PM

Quote:

Originally Posted by Zaurak3

Happy to see it worked out for you, Viking. I hope you have as many enjoyable flights as I have had with mine. Dr. Lippisch deserves the bulk of the credit for this sweet flyer!

I found a very interesting link with lots of great pictures of Dr. Lippishce's work here:
http://discaircraft.greyfalcon.us/LI...20RESEARCH.htm

viking60 · Jan 05, 2009, 08:07 PM

It's finally time to install the motor mount- and to do it in a way that allows you to control the amount of down-thrust and side-thrust. For this particular design, I decided to use 1 degree of right thrust, and just under 2 degrees of down thrust.

By building the ply plate 'firewall' with the hardwood dowel glued into a hole in it's center, I had a motor mount shaft that could then be easily oriented to these thrust line settings. The slot cut into the lower surface of the lower wing panel's foam can be easily positioned and cut to end up with the desired angles; the photo below shows how I did this step.

The circular ply plate is large enough to accomodate larger motors and motor mounts if desired.

VIKING

Jan 05, 2009, 09:48 AM	#1
viking60 High Altitude Flyer Join Date: Sep 2005 Location: Fairplay, South Park, CO Posts: 1,094	ME163-e KOMET Powered Glider For Slope & Thermals, Folding Prop The ME163-e Komet is a new powered glider design with a folding propeller in front, and a high glide efficiency wing design. It is built up from Bluecor FFF with an optional EPP lower fuselage. It was designed to roll nicely, loop well, penetrate winds well, and ride thermal lift or slope winds efficiently. One of it's most unique features is the airfoil profile of the built-up wing, based upon the MH32 airfoil. The result is a very efficient gliding wing that can penetrate winds well, yet is simple to build on a flat surface. Wingspan is 39-3/4" as shown; overall length is 26-3/8". It uses elevons and rudder as control surfaces. The wing also features eliptical upswept wing tips, and my own variant of a "KFm3 variant" dual top step implementation, with the main step at 50% of chord. Surface mounted turbulator spars are also used, placed at ~15% of chord. This Komet is designed to be powered with a variety of motors on a front firewall mount, including the 'Blue Wonder' 1500Kv motor and a 10 Amp ESC. My first prototype, just through the first test flight, is flying on a 2S 900 ABF LiPo battery at 10-3/8 ounces. With 2.2 square feet of wing area, that gives a wing loading of less than 5 ounces per square foot. I chose to use tapered balsa control surfaces to end up with very thin trailing edges to minimize drag, thereby increasing glide efficiency as well as wind penetration at modest wing loadings. The shaping of the forward section of the was given careful consideration, since 50% of a wing's lift is generated by the shape of the front 25% of the wing's airfoil. So a lot of performance can be gained, as far as glide efficiency and wind penetration ability, by carefully shaping the forward section of any wing. The ME163-e Komet has a full web page of it's own on my web site at: http://www.stenulson.net/rcflight/komet.htm Many of the design details, build sequence photos, and the preliminary rough plan are all in one place there. The build is in it's finishing stages after a very successful first flight (in very frigid zero degree conditions!) More details will be added soon! VIKING Attached Thumbnails The ME163-e Komet just before the first test flight; motor cowling not yet in place. 39-3/4" span 111.2 KB · Views: 409 The Viking MH32/KFm3v airfoil cross-section; relatively simple build yields high performance glide efficiency and good wind penetration 39.6 KB · Views: 302 Wing is built flat; tapered airfoil shaping strips are added, then top curved wing panels are glued in place. Two pairs of thin CF rod spars stacked top & bottom produce a very stiff wing 47.3 KB · Views: 230 Top surface metallic gold base coat applied, ready for the final trim-out; the bottom is Fluorescent Orange & Black 40.0 KB · Views: 218 Last edited by viking60; Jul 03, 2010 at 07:22 AM.

Jan 05, 2009, 09:49 AM	#2
viking60 High Altitude Flyer Join Date: Sep 2005 Location: Fairplay, South Park, CO Posts: 1,094	Here is the top view of the origional Me163b, and the rough plan drawing which I used to start this build. The plans will be updated with more detail when time allows. VIKING Attached Thumbnails This is the top view of the 1940's vintage Me163b; I used it as a starting point for this new design. 43.5 KB · Views: 174 This is the rough plan I used to start building the Me163-e Komet. New more detailed plans will be drawn up as time allows. 66.4 KB · Views: 243 Last edited by viking60; Jan 05, 2009 at 10:00 AM.

Jan 05, 2009, 09:51 AM	#3
viking60 High Altitude Flyer Join Date: Sep 2005 Location: Fairplay, South Park, CO Posts: 1,094	Here's a couple of the early build sequence steps; this Komet was designed as I built this prototype, starting from the rough plan and laying it out directly on a sheet of Bluecor PP. VIKING Attached Thumbnails This is the main lower wing panel that I marked out and cut first. I worked from the rough plan, laying out directly onto the Bluecor foam. Each wing tip is extended 1.5" to a total of 42" span to allow for shaping the upswept wingtips 83.4 KB · Views: 146 A vertical fuselage was designed to fit on top of the lower wing panel. Then the upper wing panels were laid out, matching the lower wing panel, extending back to the primary KF step 95.8 KB · Views: 134 Last edited by viking60; Apr 28, 2009 at 10:44 AM.

Jan 05, 2009, 04:11 PM	#6
viking60 High Altitude Flyer Join Date: Sep 2005 Location: Fairplay, South Park, CO Posts: 1,094	Once the 4 main Bluecor pieces were cut out, I started laying in the lower wing panel's pair of CF rod cap spars. these were inset flush with the surface, directly above / below each other, into shallow slots that I melted with an adjustable temperature soldering iron set to a low temperature. The CF rod spars were then glued in place with foam-safe CyA glue. Next, the Vertical stabilizer was also stiffened with another pair of 1mm CF rods. Once these CF rods were installed, the upper fuselage panel was epoxied in place. Attached Thumbnails 75.3 KB · Views: 144 43.9 KB · Views: 119 64.1 KB · Views: 154

Jan 05, 2009, 06:54 PM	#10
viking60 High Altitude Flyer Join Date: Sep 2005 Location: Fairplay, South Park, CO Posts: 1,094	These photos show the top wing panels being set in place after being trial-fitted; a bit of sanding gets everything matching up. Photo captions tell more of the story. VIKING Attached Thumbnails after curving the upper wing panels by rolling them over a ~4" diameter tobe, they are set in place and trial-fit 71.6 KB · Views: 148 After the wing tip area is rolled up, it is carefully heat-tempered in shape. The old gel cell battery keeps heat from affecting the inboard wing area 57.3 KB · Views: 133 Balsa ailerons are trial-fit. All core structures are hot melt glued in place, ready for the two top skins to be glued in place 47.3 KB · Views: 140 I've coated all contact areas with 5 minute epoxy, then weighted down this wing panel thoroughly 84.3 KB · Views: 178 Last edited by viking60; May 12, 2009 at 09:14 AM.

Jan 05, 2009, 04:02 PM	#4
Rolland Benson Registered User Join Date: Aug 2006 Posts: 130	Viking Looks like this is one fine plane. I will be hanging around to see how the flight reports do. Although not zero here I was out today and I know what you mean about the fingers getting cold fast. Rolland

Jan 05, 2009, 04:05 PM	#5
Rolland Benson Registered User Join Date: Aug 2006 Posts: 130	Viking I am curious about the rudder function. I have never built a wing with a working rudder. What is the advantage of having a working rudder with elevons? Rolland

Jan 05, 2009, 04:13 PM	#7
MYHELIGUY BUILDIN-FLYIN-CRASHIN-FUN Join Date: Feb 2008 Location: Michigan Posts: 483	viking60 now this is really a nice interesting build.does this kfm3 assist in slow flight?

Jan 05, 2009, 07:15 PM	#11
Zaurak3 Gravity-Compliant User Join Date: Mar 2008 Location: Nebraska USA Posts: 663	Happy to see it worked out for you, Viking. I hope you have as many enjoyable flights as I have had with mine. Dr. Lippisch deserves the bulk of the credit for this sweet flyer!

Jan 05, 2009, 07:44 PM	#12
viking60 High Altitude Flyer Join Date: Sep 2005 Location: Fairplay, South Park, CO Posts: 1,094	Z, Yes, my approach to building out this ME163-e variant is working out very well! There are a lot of design elements employed here that Dr. L may never have used.... a radically different airfoil, different wing tips, an implementation of the KF step elements, a different fuselage shape, and a different vertical stabilizer profile than what the ME163b used. He'd certainly smile as he recognized the silhouette as it passed overhead. And of course, once we start working with foam and thin CF rod stressed spar structures, we're firmly into the 21st century era of miniature aircraft design. The photos below show details of how the second pair of eliptical spar caps are placed to finish giving this wing structure it's incredible rigidity... when you consider that there's less than four hundredths of an ounce of CF in this set of spars, you can truely appreciate the value of these materials. The KOMET web page has more of the construction details: http://www.stenulson.net/rcflight/komet.htm VIKING Attached Thumbnails One of the second pair of 1mm CF rod spar caps is being glued in place 66.7 KB · Views: 175 This view shows the placement of the bottom members of each of the two sets of spars. 67.8 KB · Views: 149 Last edited by viking60; Jan 05, 2009 at 08:12 PM.

Jan 05, 2009, 07:58 PM	#13
viking60 High Altitude Flyer Join Date: Sep 2005 Location: Fairplay, South Park, CO Posts: 1,094	Leading edge and trailing edge shaping is critical to achieving the optimum glide efficiency performance. I start by carving away excess foam with a new razor knife blade. Sanding is useful in some areas. Then I bring out the covering iron, set carefully to a temperature where it will heat, compress, and temper the foam over a bit of time. If the iron is set too hot, it will ment the foam, and you'll find it sticking to the iron's surface. I actually end up with a bit of sanding, removing any high spots from my desired finished profile. VIKING Attached Thumbnails Once the main wing structure is complete and the control surfaces have been hinged in place, it's time to do the final airfoil shaping of the wing's leading and trailing edges, as well as thinning and firming the wing tip edges. 44.7 KB · Views: 247

Jan 05, 2009, 08:07 PM	#15
viking60 High Altitude Flyer Join Date: Sep 2005 Location: Fairplay, South Park, CO Posts: 1,094	It's finally time to install the motor mount- and to do it in a way that allows you to control the amount of down-thrust and side-thrust. For this particular design, I decided to use 1 degree of right thrust, and just under 2 degrees of down thrust. By building the ply plate 'firewall' with the hardwood dowel glued into a hole in it's center, I had a motor mount shaft that could then be easily oriented to these thrust line settings. The slot cut into the lower surface of the lower wing panel's foam can be easily positioned and cut to end up with the desired angles; the photo below shows how I did this step. The circular ply plate is large enough to accomodate larger motors and motor mounts if desired. VIKING Attached Thumbnails This fabricated birch ply & hardwood dowel motor mount is easy to install with the desired thrust settings. 65.3 KB · Views: 200

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