Me-163 Komet from Arkansas [by Klima at Apogee]

[Crawf56]

Thanks for all the comments, gents. A few responses:

MOTOR; Planning to go with D-24 [18mm]. Will order from Dynasoar this weekend. Considered going E6, but too many construction problems.

LAUNCH ROD/GUIDE: I plan to initially use a slight angle rail (NAR/AMA illegal; but I have access to an abandoned WW2 training field).

I am strongly considering make a hole through the fuselage to use as a "launch lug". I would do this using a brass tube that has been sharpened. Remove the brass tube, then add a little thin foam CA glue to reinforce the hole/tube. I would size the hole for a 3/16 launch rod.

 

[Crawf56]

Goerge Gassaway may be a good source of "inspiration" . . .

http://georgesrockets.com/GRP/LaunchGear/Glider_Tower.html

http://georgesrockets.com/GRP/LaunchGear/PadTower2011.html

Dave F.

Gosh, I haven't looked at George's pages in ages. Thank you for the links.

 

[Crawf56]

Ever forward. Assembling the hatch/canopy.

 

[Cape Byron]

LAUNCH ROD/GUIDE: I plan to initially use a slight angle rail (NAR/AMA illegal; but I have access to an abandoned WW2 training field).

Strangely appropriate.

 

[Daddyisabar]

I just got formal word from AMA that they require any rocket motor usage even fixed to R/C aircraft to follow NAR guidelines, ie unmodified motors(no plugging) and you must also follow the 45 degree maximum from vertical launch angle, so what they show in the video would not be permitted at an AMA insured flying site or at tripoli or nar launches, so you are limited to trying that at a super secret covert base of operations and good idea not to provide video evidence for the prosecution

Oh forgive me Mommy Dearest. I was coerced by a German YouTube video. I made contact with a wretched hive of scum and villainy, launching from a private, undisclosed location on the high Western plains. I am a good boy having made my ME 163 launch rails from WIRE HANGERS!

 

[Daddyisabar]

Too bad. Komets are soooo cool.

 

[tab28682]

I learned something today, and for that, I thank you.

To add a bit to what Frank said:

This foam molded Komet is/has been offered as an electric powered ARF by Hacker, so, luckily, the RC RG market did not have to support the full cost of the injection molded tooling, alone.

Ive flown the electric version of the Klima modela number of times and the handling is excellent. Not a trainer, but great as a 3rd or 4th RC model. I also have tons on flights on the two different version of the electric HobbyKing Komet, with and without air started rocket power.

I started a build thread here on this model a few years ago. It is built and ready to paint, but was overtaken by other model desires...

I still think I can bring this in a boost weight well under 300 grams and be able to launch it off a NAR legal angled pad on a D2.3

 

[aerostadt]

Here's a thread from about a year ago. Sounds like a challenge.
https://www.rocketryforum.com/threads/klima-me-163.154735/page-2
Here's thread started by Tom. There are several thread/topics/posts on TRF.
https://www.rocketryforum.com/threa...glider-kit-a-mini-review.133259/#post-1570529

 

[tab28682]

The problem with komets is they can be really pitchy on boost if set up too far AFT with CG but then at burnout the CG is nose heavy and they run out of pitch authority, so you are always skirting with aft cg to help glide/flare. They have a relatively short nose moment and long tail so the motor is mounted pretty far aft relatively and small elevon surfaces don't help as much for the CG shift. Heavier motors require at least or more nose weight than the motor weight difference.

In general, I agree that Komets can be a bit problematic in the smaller sizes. I still think the Klima has unrealized possibi!ities. Properly balanced, with reasonable control throws and with a little ramp angle, the model that Apogee tried to fly should work fine. How experienced was the Apogee pilot?

When you get just a little bigger, the Hobbyking Komet is completely flyable when ballested for a 18mm motor, even after burnout. Here is a video of my airstarted HK Me-163:



Zero problems landing with zero power after this boost. I have no doubts it would work fine on a 24mm E15 or similar as a pure RC RG with the electric power system removed.

Dave Schaefer has had excellent results with his 60" span ARF fiberglass fuse Komet that comes with built up balsa wings covered with monokote type covering. He typically flies on an RMS I-161 or a single use DMS I-140. At this size, the CG shift With the 38mm I motor is workable. It does fly little nose heavy, but it flies well. This flight had a rather flat boost angle, but I have seen other local flights where it boosted at 70-80 degrees. Always impressive.

 

[aerostadt]

Wow! In general Komet seems to glide very fast. George Gassaway also had a TRF-post reference for a Durafly Komet with a small motor air-start.
https://www.rocketryforum.com/threa...glider-kit-a-mini-review.133259/#post-1570529

 

[tab28682]

Wow! In general Komet seems to glide very fast. George Gassaway also had a TRF-post reference for a Durafly Komet with a small motor air-start.
https://www.rocketryforum.com/threa...glider-kit-a-mini-review.133259/#post-1570529

Very much dependant on wing loading. It can be fast or slow, depending.

 

[burkefj]

I have done a couple of 36-38" span profile komets that fly and glide fine on E-6 motors but they have to be balasted to around 14 oz so don't boost super high.

Tom was asking about the skill of the pilot that tried to fly Tim's example at NSL and it was a kid looked like he was late teens early twenties so I don't know how much experience he had but it definitely wasn't trimmed and flying on a d24 boosting straight up it was flopping all over.

 

[tab28682]

Thanks for all the comments, gents. A few responses:

MOTOR; Planning to go with D-24 [18mm]. Will order from Dynasoar this weekend. Considered going E6, but too many construction problems.

LAUNCH ROD/GUIDE: I plan to initially use a slight angle rail (NAR/AMA illegal; but I have access to an abandoned WW2 training field).

I am strongly considering make a hole through the fuselage to use as a "launch lug". I would do this using a brass tube that has been sharpened. Remove the brass tube, then add a little thin foam CA glue to reinforce the hole/tube. I would size the hole for a 3/16 launch rod.

Remember, a " slight angle rail" is NOT a violation of the NAR safety code. The NAR allows a 30 to 45 degree launch angle from vertical for RC RGs, as described in the RC RG Safety Code.

https://www.nar.org/safety-information/radio-control-rocket-glider-safety-code/
Many rocket folks are unaware of this exemption.

Personally, I would go with a D13 and a launch angle of 15-20 degrees from vertical. Things will happen a little slower and give you some extra reaction time.

As long as the CG is correct at ignition, the wings are warp free, sensible control rates are set And the elevons are correctly centered, the Komet is unlikely to give any significant problem on launch.

Something to consider on a rail launched Komet with a full fuselage is the offset distance from the motor centerline to the rail buttons, especially if you put the rail buttons on the landing skid. The thrust offset and short spacing of the buttons can cause drag on the rail and a possible pitch after it clears the rail, depending on the speed it leaves the rail.

An internail launch lug next to the motor mount eliminates this issue, as would an adjustable launch tower with four rails.

My plan was some sort of simple ajustable four rod tower.

 

[Ez2cDave]

My plan was some sort of simple ajustable four rod tower.

Look up George Gassaway's "Omni-Pad" . . .

http://georgesrockets.com/GRP/LaunchGear/PadTower2011.html

Dave F.

 

[TheAviator]

To add a bit to what Frank said:

This foam molded Komet is/has been offered as an electric powered ARF by Hacker, so, luckily, the RC RG market did not have to support the full cost of the injection molded tooling, alone.

Ive flown the electric version of the Klima modela number of times and the handling is excellent. Not a trainer, but great as a 3rd or 4th RC model. I also have tons on flights on the two different version of the electric HobbyKing Komet, with and without air started rocket power.

I started a build thread here on this model a few years ago. It is built and ready to paint, but was overtaken by other model desires...

I still think I can bring this in a boost weight well under 300 grams and be able to launch it off a NAR legal angled pad on a D2.3

On a D2.3, the sustain thrust starts at 200 grams and tails off to about 150 grams at the end of the burn. My ELF comes in at ~120 grams and flies amazingly on a D2.3. Personally, I would not feel comfortable with about more than 150 grams lift-off mass on a D2.3 with a rocket glider. Even then, it could get really mushy at the end of the burn. I'm sure Frank could give more recommendations for sport rocket gliders.

 

[burkefj]

On a D2.3, the sustain thrust starts at 200 grams and tails off to about 150 grams at the end of the burn. My ELF comes in at ~120 grams and flies amazingly on a D2.3. Personally, I would not feel comfortable with about more than 150 grams lift-off mass on a D2.3 with a rocket glider. Even then, it could get really mushy at the end of the burn. I'm sure Frank could give more recommendations for sport rocket gliders.

The most I've personally flown is 7 oz with a vertical boost off of a rail transitioning to about a 40 to 45 degree climb, and that boosts to maybe 250 ft or so with a fairly good size Wing area of about 1.5 square feet, with a 45° rail angle I don't know how much heavier you can go.

 

[TheAviator]

The most I've personally flown is 7 oz with a vertical boost off of a rail transitioning to about a 40 to 45 degree climb, and that boosts to maybe 250 ft or so with a fairly good size Wing area of about 1.5 square feet, with a 45° rail angle I don't know how much heavier you can go.

That makes sense, 7 ounces is ~200 grams. As you note though, you can't climb vertically at that mass.

 

[Crawf56]

Got my stuff from Dynasoar Rocketry. Here is the D-24 reloadable motors. Comes in a 3-pack.

 

[Crawf56]

Here is the silver motor mount tube that comes with the kit. Next to it is the casing for the reloadable motors.

 

[Crawf56]

Here is the silver motor mount in the Me-163 (not epoxyed yet). And how it looks with the 18mm casing.

Still considering how I want to detail this. The Me-163 instructions talk about using tape and a friction fit to hold the motor (no ejection charge). I might add an engine hook.

 

[Crawf56]

Glued the rudder on. Using 12-minute epoxy.

 

[Crawf56]

Working on the nose. There is some excess foam you have to remove.

 

[Crawf56]

And the nose cone is glued on.

 

[Crawf56]

Working on the motor mount. Decided to add the engine hook.

 

[Crawf56]

There was a raised spot on the inside of the wing opening. A little cutting, a little sanding got it fixed.

 

[Crawf56]

Attaching the aileron horns, included in the kit. Will trim the piece on the top of the wing.

 

[Crawf56]

Attaching the magnets, for holding the top hatch. Must be careful to get the polarity right on the magnets.

 

[Crawf56]

Ok, I decided to make an opening for a launch rod through the Me-163 fuselage.

This starts with a 3/16 inch diameter brass tube, that has been filed at one end to cut into the foam.

 

[Crawf56]

If I were smarter, I would have marked the half sections of the fuselage before assembly, and made an opening.

 

[Crawf56]

My brass rod was not quite long enough, had to hold it with a wrench at times. Still was difficult.

The exit hole is 3/8 inch below the bottom of the engine mount.