Schapel Sa882 - Page 2 - RC Groups
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Nov 17, 2012, 11:10 AM
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Starting to glue the ply on. Best to take it slowly and make sure that it is nicely glued/weighted down. Much of the sheets fixed so far are next to open framework, but some with overlapping ply have scarfed joints. The 0.6mm ply is quite thick and this is easier than one might imagine to achieve with a sanding block.

I have now obtained tanks that are 14 oz so will have 840cc. This will be enough for a flight of 5-6 minutes. The rear of the tank will protrude a little above the wing skin so I will have to add 2 blisters. I was thinking of 4 tanks like Andres, but I want to fit retracts and am running out of space!
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Nov 17, 2012, 02:57 PM
Tailless Happy
HortenI's Avatar
Hope to see you 2013 in Cologne with the H IX and the Sa882

Nov 18, 2012, 04:11 AM
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Yes we hope to make it to Porz this year. I am spoilt for choice with planes though. Do I take the Arado 555, the large Boulton Paul P111 or the Horten. The Schapel is so small it will fit in easily on top of everything.

Nov 18, 2012, 12:11 PM
Just call me crash for short
Quick61's Avatar
I have to say, this is a most excellent build. Please keep the info and pictures coming. It's inspiring stuff, and someday I hope to be able to build as well as this.

Nov 19, 2012, 09:14 AM
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Tijgerhaai's Avatar

Great Job

Hi John,

You are doimh a great job. It all looks clean and well done. The plywood building is not the easiest way to build a Horten, but it makes very strong and beautifull looking planes.


Nov 19, 2012, 10:21 AM
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Thanks Mark and Lothar for the encouragement. I have not made a plywood finish plane before, I have usually done balsa skin and glass cloth with filler and painting. The ply finish is very quick but as I have discovered the ribs must be sanded before sheeting so they flow properly from one to another. It seems strange to have no filler. I can see that this should be light and strong as a result.

Nov 20, 2012, 05:52 AM
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A few more pictures of sheeting the top surface. This went smoothly except an annoying stain on one wing where I weighted the joint down with a steel block and there was a little ooze of glue. I can touch this up to mask it. I cleaned up the nose sheeting with a plane and a Permagrit block. Pleased that the care I took in the cleaning up of the ribs and nose spar is reflected in a nice tight glued joint with no gaps. Now I have run out of ply and am waiting on a delivery this morning. The rather fuzzy shot of the leading edge shows the complex shape of the leading edge. It is not a simple twist in the wing to give the washout, and no I do not have a bend in my building board!
Nov 21, 2012, 09:29 AM
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Finally I have all the panels glued on except the centre ones over the fuel tanks. I will leave these till I have the other side sheeted.
For the centre panels I have used 1.6mm thick ply to beef it up in the area of the nose leg and the fuel tanks. This leaves a slightly raised panel which I am happy with. Tomorrow I will remove it from the building board.

Nov 21, 2012, 10:20 AM
Just call me crash for short
Quick61's Avatar
Looking good. Like the weight selection, drill press vice, lathe chuck, (off a jewelers lathe / Sherline?). Whatever works, right. Seems like your getting closer to mounting up the turbine. Keep it coming.

Nov 22, 2012, 10:09 AM
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Now I have the plane off the building board. This comes away with the sub ribs fixed to the wing by use of a chisel to break the hot glue joint. Hot glue seems a good choice for setting the temporary supports in place.

The sub ribs are carefully sawn off the ribs. I used a tenon saw. The underside is not as pretty a sight as the top surface as I had realised when I was building it. There will be plenty of cleaning up to do.

The new set of templates for the upper wing surface are then glued with hot glue onto the building board after all glue is cleared off. These are glued on except for the centre rib and the wing can be rested in position. I was pleased that the wing fitted snugly in place without being out of shape. I am now cleaning up before I can think about sheeting the underside surface. I also had my first weight check and it will be interesting to see if I can keep it close to the 3.4 Kg that Andres version weighed.
Nov 23, 2012, 03:05 PM
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I finished cleaning up the underside and then glued on the balsa cap pings ready for sanding. I then took a look at the nose leg. I made a birch ply plate 1/4" thick to take the retracts. I am not worried about the weight as I know I will need nose weight and I would rather have a strong structure and less nose weight. I copied the Habu style nose steering arrangement which is nice and neat.

I made the nose leg offset so as not to compromise the structure too much. It is unusual but not unheard of to have offset nose legs.

I need the triangular spaces at the front for lead and the space on the other side from the retract for batteries. I shall have 2 cell A123 1100 mAh batteries for both rx and ecu. There is always very little room on my planes for all the electronics but I think I should be able to fit it all in ok.

Nov 23, 2012, 04:04 PM
less is more
Knoll53's Avatar
So John, do you have target wing loading for this buggy yet?

Gotta be at least 60 gr/dm. Should make for some dramatic scale-like high speed landings.

This is going to be fun.

Nov 24, 2012, 04:02 AM
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I would be happy if it is 66 gm/dm as that will be quite a light wing loading.

If you look at this video you will see my Swift glider from Topmodel which is 3.14m and has a wing loading of 110 gm/dm at takeoff.

This is flying with the same motor I will be using on the Schapel.

I monitored flying speeds and G forces with this model and had positive 8G negative 5G and a max speed of 140mph. It lands quite slowly and predictably.

The heaviest loaded wing with my motor is the Opus jet that Ali flew. This was absolutely ballistic.

Ali Machinchy loses a Turbine. April 21, 2012 (2 min 37 sec)

I expect the Schapel will fly faster than the glider but I will take measurements and report back.

Here is video of Andres plane. The engine he has is lighter than mine, also it has no
retracts. The retracts will help low it on landing and I will use crow with the flaps and elevons.

Last edited by John Wright; Nov 24, 2012 at 05:00 AM.
Nov 24, 2012, 05:25 AM
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andrecillo76's Avatar

great video of the Opus! The wing might have been "tested up to 40g", but obviously not the turbine mounting . A friend an me have this crazy idea of a similar ballistic CFK-wing: "The Speedolin" (see attachment below for a snapshot of the CAD). We've been undecided on the size though, as we expect very high speeds way over 350 km/h. Anyway, maybe some day...

For the large Schapel, we measured speeds of up to 220 km/h (~135 MPH). Considering the higher thrust of your turbine and slightly higher wing loading your's will have, I think 245-250 km/h (~150 -155 MPH) might be achievable.

Nov 24, 2012, 12:45 PM
Hallo von Dresden
Hi Ándres ... over 350 Kmh? where are you going to test this thing? at the local ballistic missile test range?? somehow the idea of something like that is to be honest a bit too dangerous for me. Imagine this thing suddenly loses its reciever and crashes into someone. A wing that can survive 40 G is very strong and if something like this hits somebody? ... no thanks.


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