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Old Nov 24, 2012, 02:22 PM
less is more
Knoll53's Avatar
United States, CA, Marina
Joined Sep 2006
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Yea, you might want to check your battery connections before flying this one....

Don't kid yourself though, most RC is dangerous. I just built a pointy fiberglass fuselage nose on a plank and have come to realize that I don't think I want to hand catch this one, let alone get in it's way when it is moving 100Kmh.

Kent
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Old Nov 24, 2012, 03:58 PM
Hallo von Dresden
Joined Sep 2012
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True enough Kent,

I have done enough damage to myself with runaway props in the shop not to think about some of the close calls on the field and I fly lightweight stuff. Now imagine 350 Km/h (about 200 MPH for those in the colonies ). I would not want to be around if this thing suddenly loses its bind or some other calamity befalls it. At some point one might want to ask the question " just because I can ... should I ?"

There enough stories about accidents to fill these pages, when I started in the model RC arena a few years ago the LHS guy told me a story about two guys who bought the farm at the same time when some high risk turbine fired model lost its link to the ground and bored through both guys. Neither one lived to tell the tale. Another story he knew to tell me was some poor guy in Switserland who died after getting whacked with one of those nine meter gliders that he had foolishly let get to close to himself. Apparently he got hit in the head and that was that. 25 Kilos worth of glider moving at 100 plus Km/H has a alot of energy and if you happen to be in the right place at the wrong time ...

Really the question is at what point does this turn from a hobby with some risks to a engineering project with very high risks? And is it at that point still a hobby or a true research and development program that should be carried out under a very much stricter set of guidelines, and at that under very controlled cirumstances.

In the video I though I heard a voice over a PA system calling out the flight ... , very questionable in my eyes letting that thing up in front of an audience. And then it falls apart mid-air. It seemed nearly impossible to film due to the high speeds and even on the best resolution I had a hard time trying to figure out exactly how the damn thing was oriented. Need I say more.

Granted the pilot was very good to keep it under control but this type of technology is available to anyone who can afford it ... so theoretically some half wit can get a hold of this stuff because it is cool and goes like hell ... fun till it falls apart or kills someone.

Ok rant over

Jens
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Old Nov 24, 2012, 04:11 PM
Herk
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Virginia USA
Joined Jun 2007
1,653 Posts
Hi Jens,

Speaking of "your stuff" ????????

I'm experiencing severe withdrawal symptoms. -- Herk
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Old Nov 24, 2012, 04:24 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,382 Posts
Quote:
Originally Posted by HerkS View Post
Hi Jens,

Speaking of "your stuff" ????????

I'm experiencing severe withdrawal symptoms. -- Herk
Ditto,hope you are keeping well Jens.
Stuart
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Old Nov 24, 2012, 04:28 PM
I don't like your altitude
Stupot46's Avatar
Joined Sep 2011
3,382 Posts
Quote:
Originally Posted by Knoll53 View Post
Yea, you might want to check your battery connections before flying this one....

Don't kid yourself though, most RC is dangerous. I just built a pointy fiberglass fuselage nose on a plank and have come to realize that I don't think I want to hand catch this one, let alone get in it's way when it is moving 100Kmh.

Kent
Don't want to keep hijacking Johns thread,but I came across this the other day
http://www.rcgroups.com/forums/showt...+fin+air+brake
Seems a simple enough mod.
Stuart
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Old Nov 25, 2012, 02:33 AM
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Heidelberg
Joined Oct 2009
379 Posts
Jens,

that's one reason why we have not invested more time into the project. We got cold feet at the glance of the estimated terminal speed for a T25 Kolibri (over 400 km/h or 250 MPH for overseas). That's a topic on which I've been thinking about the last years. I think that some regulation will be introduced in the near future here in Germany...

Anyway, back to the Schapel, which has a great size to thrust ratio and will fly nicely and not ballistic!

Cheers,
Andrés
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Old Nov 26, 2012, 07:41 AM
Hallo von Dresden
Joined Sep 2012
55 Posts
@ Herk and Stuart,

Hello gentlemen, well I have been busy with some flying machines but they are not flying wings. A 2.75 Meter Glider as well as a 2.25 meter which is currently on the table recieving a custom retractable powerplant. So yes I am doing things but because they are not Flying Wings per se they are not here. There is a build thread on a German Forum where some pics of the Schleicher K8b can be seen. It is a rather slow build though as the past months have been terribly busy with many things. Hopefully now that the storm is over in my life (the last one passed this weekend as matter of fact) I will be able to refocus on things. But for now let us give John his thread back. It is really a great build he has going here.

Jens
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Old Nov 26, 2012, 12:19 PM
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Colchester UK
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Not much to show for todays work. The leads are cut to length and have plugs crimped on them. I labelled them with a silver fine paint. The retracts are now sorted out. I decided to fit the mains so they could have a bearer that was glued onto the main spar at one side and the rear spar at the other. The other side of the mount is made from infilling the existing spar so it is solid except where the cut out is made for the electric motor. The ply work for the retracts I glue with Epoxy so it is not as neat to look at, but is much stronger.

The nose retract is glued in place and the space divided so the other side can accommodate the batteries.

The most important thing is get a few degrees of positive angle of attack or it will not get airborne. On the Horten it is 7 degrees but that brings problems with the landing and the plane 'pogo-ing' on the nose leg if the approach is too flat and fast. I have got about 5 degrees with the Schapel so hopefully this will work out ok. Fortunately the retracts come with some axels that can be clamped on the leg enabling me to get the length correct when I cut it. The photos show the testing process.

The engine thrust line will need careful attention and I will rework the design that Andres developed. I really want the engine and thrust tube to be angled up at the rear by 4 degrees.

All the retract system is very simple and light, I just hope they will be robust enough.

I have the servo mounts and wheel wells to install before I can start to sheet the underside. This is turning out to be a quick build for me.

John
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Old Nov 26, 2012, 12:32 PM
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Colchester UK
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Couple of pictures showing the longer nose leg and shorter mains. It will be better to show the plane on its wheels and will take a pic in the next few days.

John
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Old Nov 26, 2012, 05:48 PM
Tailless Happy
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Germany
Joined Jan 2009
43 Posts
Nice pictures !
The P111 looks interesting.

Regards Jörg
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Old Nov 27, 2012, 03:23 AM
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Colchester UK
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Thanks Jorg

Yes the P111 is interesting. It is a moulded centre section with foam wing tips. It is large and heavy and has not flown yet as I had to get it approved under the UK Large Model Association for over 20 Kg. More info on RCU.

John
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Old Dec 06, 2012, 10:26 AM
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Colchester UK
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Had flu which curtailed workshop activities, but now back.

Fitted blocks to upper surface to hold servo frames. These plastic servo frames are great, they fit all well known servos and allow them, to easily be removed with 2 screws. They are very well made and are light. I secure mine with 4 small screws and Hysol (after sanding the plastic).

The frames come from Germany

http://www.servorahmen.de/index.php?id=40

I am fitting both the flap and elevon servos so the arms project through the underside skin. This means they are fixed to the upper surface and the cover is just for access. As I am using retracts I am not worried about damage to the servos with a grass landing.
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Old Dec 06, 2012, 11:01 AM
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Colchester UK
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Fitted wheel wells made from spray can tops and glued into 0.6mm ply sheet with Acrylic glue. Makes a very light arrangement.

Balsa blocks glued in for fitting the horns into, also the small ribs for the ends of the flaps and elevons glued in place. I was keen to keep the shape of the elevons and flaps as exactly correct as possible so I glued in the balsa strip in place. This has an allowance for 5mm of down elevon movement. I anticipate 80:20 differential aileron movement with a lot more up than down required. The hinges will be hinge tape as is used on my Topmodel glider. This is now a year old and had plenty of turbine powered high speed flights and it has tape for the hinge. Despite having fuel spilt over them there is no peeling or cracking of the tape and I am happy that they are robust enough.If you look very carefully on this photo the line of the top surface can be seen. When the elevons and the flaps are cut off they will only need the ribs to be cut through. I will have the elevons top hinged and the flaps bottom hinged.

John
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Last edited by John Wright; Dec 06, 2012 at 11:10 AM.
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Old Dec 06, 2012, 11:14 AM
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Colchester UK
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Finally made a start today on sheeting the bottom surface. The elevons were sheeted first. I found that I had the upper surfaces just a little large (wide) so made the bottom ones the correct size. The ply is sanded so the trailing edge is as sharp as possible.

The difference between the flap and elevons can be seen with the flap sheet just pushed into place.

John
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Old Dec 08, 2012, 11:27 AM
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Colchester UK
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More progress on sheeting the underside. For those that may not have appreciated it the ply sheet is 0.6mm thick, which needs a nicely prepared set of ribs and spars to sit accurately.

On the underside it is tricky to find a clamping regime that clamps the front and rear edges tightly in place with no gaps. I couldn't use clamps as the curve of the top side sheet was too rounded and the clamps slipped off. After much experimenting I used brown parcel tape wrapped round the D box. I put lengths of tape in place before gluing. Just be careful to ensure that you have even pressure so the leading edge is not wavy. Check they are pulled up tight.

Unfortunately I am very sensitive to CA glue as well as Acrylic and both make my sinuses swell. I therefore now tend to use only yellow aliphatic glue, which is a bit messy and does take a while to go off enough to release clamps. Progress is not as fast as I would like.

I made the servo hatches from the material cut out of the ply sheet. I glued the ply lips onto the ply skin before gluing the ply skin in place. The corners are reinforced
with 1.6mm ply sheet. I will screw them in place with miniature screws recently purchased. The Elevon hatches will have only 2 screws in place and the flaps will be 3 screws. I have glued hatches with CA before as this does not require a big force to ease them off if needed. Screws are much easier though.
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