Thread Tools
Jan 05, 2009, 10:48 AM
High Altitude Flyer
viking60's Avatar
Thread OP
Build Log

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


The ME163-e Komet is a 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 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 elliptical up-swept wing tips, and my own variant of a KFm3 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. (3s 850 batteries flown most of the time later.) 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 wing's airfoil 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.

VIKING
Last edited by viking60; Sep 08, 2013 at 07:51 PM.
Sign up now
to remove ads between posts
Jan 05, 2009, 10:49 AM
High Altitude Flyer
viking60's Avatar
Thread OP
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
Last edited by viking60; Jan 05, 2009 at 11:00 AM.
Jan 05, 2009, 05:02 PM
Registered User
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, 05:05 PM
Registered User
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, 05:11 PM
High Altitude Flyer
viking60's Avatar
Thread OP
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.
Jan 05, 2009, 05:13 PM
BUILDIN-FLYIN-CRASHIN-FUN
viking60
now this is really a nice interesting build.does this kfm3 assist in slow flight?
Jan 05, 2009, 05:25 PM
High Altitude Flyer
viking60's Avatar
Thread OP
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 fixed vertical 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
Last edited by viking60; Nov 26, 2011 at 10:40 AM.
Jan 05, 2009, 05:29 PM
High Altitude Flyer
viking60's Avatar
Thread OP
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
Last edited by viking60; Jan 05, 2009 at 05:34 PM.
Jan 05, 2009, 08:15 PM
Gravity-Compliant User
Zaurak3's Avatar
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, 08:44 PM
High Altitude Flyer
viking60's Avatar
Thread OP
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
Last edited by viking60; Jan 05, 2009 at 09:12 PM.
Jan 05, 2009, 08:58 PM
High Altitude Flyer
viking60's Avatar
Thread OP
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
Jan 05, 2009, 09:03 PM
Registered User
Dickeroo's Avatar
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
Jan 05, 2009, 09:07 PM
High Altitude Flyer
viking60's Avatar
Thread OP
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


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion folding prop for flying wing rcnutt Flying Wings 13 Mar 19, 2009 09:12 PM
FS,11x8 Folding prop, 8mmcarbon wing rod,odds and ends Wetcoast Aircraft - Sailplanes (FS/W) 3 Feb 07, 2005 05:39 AM
E-jet, Cobalt Motor, Folding Prop swingkat420 Aircraft - Electric - Airplanes (FS/W) 2 Jun 29, 2004 09:59 PM
Folding prop on a wing jgrog76 Foamies (Kits) 3 Mar 03, 2004 05:43 PM
Using an ESC without Brake Disable with A Fixed Non Folding Prop/ Safe? Joe Elston Electric Plane Talk 4 May 10, 2001 10:35 PM