De Schelde designations

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More holes than filling but here's a start on De Schelde designations. Can anyone fill gaps or add other designations?
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De Schelde Aircraft Designations

De Schelde inherited staff and designs when it took over the failed Pander & zonen firm. Both the services of chief designer Theodorus Slot and his as-yet-unbuilt designs were part of that deal. Thus, from Pander, de Schelde took on the 'S' (for T.E. Slot) designation style as well as a construction number sequence. As a result, the very first aircraft designed at de Schelde - the S.12 monoplane prototype - was assigned c/n 48.

Although Theo Slot designed the unfortunate S.12, it is not clear whether 'S' still stood for Slot at that time ... or if it simply stood for 'Schelde'.
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De Schelde 'S' Series Aircraft Designations

De Schelde S.1 - (Project) Pander commercial transport/airliner*
- De Schelde S.1 : Engines in leading edge driving tractor props
-- Light engines; but sources differ on whether 4- or 6-engined
-- * Claims of ' twin-booms' probably confusion with larger S.26

De Schelde S.2 - (Project) Pander commercial transport/airliner
- De Schelde S.2: Wing-mounted engines driving pusher props
- De Schelde S.2: 4 x 120 hp De Havilland Gipsys;* span (??)
-- * Pander: Een Haagse vliegtuigbouwer, Harm Hazewinkel

De Schelde S.3 - (Project) Pander commercial transport/airliner
- De Schelde S.3: High-wing trimotor; underwing engine gondolas
- De Schelde S.3: Proceeded final S.4 concepts; no other details

De Schelde S.4 - (Project) 1934 Militair; S.4 Postjager devel.
- De Schelde S.4: Long range recce/medium bomber monoplane*
-- * Derived from Slot's Pander S.4 Postjager mailplane
- De Schelde S.4: Listed as the S.4-militair (not a name)
- De Schelde S.4: Retractable dorsal & ventral gun positions**
-- * 6 x fwd-firing cowling mgs; 1 x dorsal mg; 1 x 'dustbin' mg
-- https://www.secretprojects.co.uk/th...aft-projects-and-prototypes.5276/#post-222783

De Schelde S.5 - (??) hypothetical designation

De Schelde S.6 - (Project) 1934 Pander* monoplane airliner study
-- Discussions with KLM after 1934 DC-2 'Uiver (PH-AJU) crash
- De Schelde S.6: 8-pax in cabin; low-wings;** rear-retr. main u/c
- De Schelde S.6: 2 x 650 hp Wright SR-1820-F2s; [1] span (??) m
- De Schelde S.6: Common airframe with inline De Schelde S.8
-- * In 12 Jan 1935 letter, S.6 described as "Postjager type"
-- * Unclear if this refers to constr. type or simply a monoplane
-- ** Wings tapering fuselage-to-tips (despite clear DC-2 influ.)
- De Schelde S.6: aka 'Schelde I' (marked on the display model)
-- NB: Model showed radial S.6 to starboard; inline S.8 to port

De Schelde S.7 - (??) hypothetical designation

De Schelde S.8 - (Project) 1934-35 low-wing monoplane airliner
- De Schelde S.8: Common airframe with radial-engined S.6
- De Schelde S.8: 8-pax in cabin; low-wings; rear-retr. main u/c
- De Schelde S.8: 2 x 620 hp Jumo 205 diesels;* span (??) m
- De Schelde S.8: Prob. meant as medium type for KLM NEI routes
-- * Junkers orig. desig. Jumo 5; 9-205 was an RLM desig.
- De Schelde S.8: aka 'Schelde I' (marked on the display model)
-- NB: Model showed inline S.8 on portside; radial S.6 on stbd.

De Schelde S.9 - (??) hypothetical designation

De Schelde S.10 - (Project?) Several suggested possibilities
- S.10 : Poss. a monoplane airliner type in S.6 & S.8 series*
-- * Peter Knippels mentions "S.10" together with S.6 & S.8
- S.10 : Poss. number for jachtkruiser marked as 'Schelde II'
-- https://www.secretprojects.co.uk/th...ojects-and-prototypes.5276/page-3#post-805063

De Schelde S.11 - (??) hypothetical designation

De Schelde S.12 - 1935 3-/4-seat,* low-winged cabin aircraft; x 1
- S.12: Slender fuselaged monoplane w/ trousered main u/c legs
- S.12: 1 x 130 hp DH Gipsy Major inverted 4-cyl.; span (??)
- S.12: Theo Slot design for Klaas de Geus van den Heuvel [2]
- S.12: Proved seriously overweight but was accepted anyway [3]
-- * Seating may have been reduced to allow for weight gain
-- NB: Peter Knippels makes no mentions an "S.12" together with the S.6 & S.8

De Schelde S.13 - (Project?) unconfirmed

De Schelde S.14 - (Project?) unconfirmed

De Schelde S.15 - S.18 - (??) hypothetical designations

De Schelde S.19 - (Project) Twin-engined, 4-seat 'jachtkruiser'*
- S.19: Twin-boomed; mid-placed wings; metal constr.; tricycle u/c
- S.19: 2 x engines (various V-12 or radial types);** span (??) m
- S.19: Armament: 2 x moveable cannons in the nose (20 or 23 mm)
- S.19: Armament: 4 x fixed wing mgs; flexible 7.9 mm mg in rear
- S.19: Armament: Offensive payload, 250-500 kg bombs in fuselage
- S.19: No drawings; presumed similar to Fokker ontwerp 163 [4]
-- * Jachtkruisers were bomber-sized multi-seat heavy fighters
-- ** Suggested engines = 2 x 1,080 hp Daimler-Benz DB 600G IV-12s
-- ** Alt. engines = 2 x 1,050 hp Rolls-Royce Merlin II V-12s
-- ** Alt. engines = 2 x 1,282 hp Bristol Hercules 14-cyl. radials
-- The S.19 met requirements but IML placed no order for the type [5]

De Schelde S.20 - 1940 twin-boomed pusher cabin monoplane; x 1
- S.20: 4-seater (1+3) sports a/c; mixed constr.; retract. tricycle u/c
- S.20: 1 x 160 hp Hirth HM 506A inverted 6-cyl.; span 11.35 m
- S.20: (As flown) metal booms; plywood-covered wooden wings
- S.20: (Planned) production aircraft to have metal wing constr.

De Schelde S.21 - (Project) Single-seat, twin-boomed fighter; x 1*
- S.21: Low-winged; twin-boomed; pusher-propeller; tricycle u/c
- S.21: 1 x 1,085 hp Daimler-Benz DB600G IV-12;** span 9.00 m
- S.21: Highly-glazed cockpit w/ flexibly-mounted Madsen 23 mm
-- * Prototype constr. near complete in May 1940; seized by DE
-- ** Alt. engine 1,030 hp R-R Merlin II (or confusion with S.22?)
-- https://www.secretprojects.co.uk/threads/de-schelde-s-21-fighter.7327/

De Schelde S.22 - (Project) Single-seat, twin-boomed fighter a/c
- S.22: High-winged S.21 alternative to 1938 fighter specification
- S.22: 1 x 1,030 hp Rolls-Royce Merlin II pusher; span 9.00 m
- S.22: Flex nose cannon; 2 x cannons in wings; 2 x 7.9 mm mgs

De Schelde S.23 - (??) hypothetical designation

De Schelde S.24 - (Project) 2-seat recce aircraft; related to S.22
- S.24: All-metal constr.; twin-boom; high-winged; pusher prop
- S.24: 1 x 650 hp Isotta Fraschini Asso 120 IRC.40; span 9.00 m
- S.24: Armament: 3-4 fixed mg in nose; 1 x flexible mg in rear*
-- * Optional additional armament: 1 x rear-firing mg motor-gun
-- * Optional additional armament: Wing racks for 50 kg bombs
- S.24: Initially passed over, work renewed in 1939; cancelled**
-- ** Cancelled due to purchase of Fokker G.1s meant for Spain

De Schelde S.25 - (Project) 2-seat 'combat' aircraft (recce type?)
- S.25: All-metal; twin-boom; mid-placed gull-wing; pusher prop
- S.25: 1 x 690 hp Isotta Fraschini Asso 120 IRC.40; span 9.00 m
- S.25: Armament: 3-4 fixed mg in nose; 1 x flexible mg in rear*
-- * Optional additional armament: 1 x rear-firing mg motor-gun
-- * Optional additional armament: Wing racks for 50 kg bombs
- S.25: Oct 1938, IML recommended further development of type

De Schelde S.26 - (Project) 50-pax long-range KLM airliner concept
- S.26: Large airliner for NEI routes; pax in fuselage & in wings
- S.26: Twin-boomed airframe; 6 x engines driving pusher-props
- S.26: 6 x wing-mounted engines (type unknown); span (??) m
- S.26: aka ontwerp 75
-- https://www.secretprojects.co.uk/attachments/de-schelde-s-26-jpg.132791/

De Schelde S.27 - (Project) Poss. ontwerp 76 4-engine mailplane [6]
-- Ontwerp 76: Long-range mailplane for KLM (planned route unknown)

De Schelde S.28 - (Project) High-winged monoplane sportsplane
- S.28: 2-seat* monoplane outgrowth of biplane Scheldemusch
- S.28: 1 x 100 hp engine** mounted on top of wing; span 12.00 m
- S.28: Wing profile same as used by Scheldemusch; wing area 18 m²
- S.28: Wings braced to fuselage & tailplane; retractable trike u/c
-- * Tandem "tweezitter met korten neus" (short-nosed 2-seater)
-- ** Hirth engine (HM 504?) used for S.28 performance calculations

De Schelde S.29 - S.31 - (??) hypothetical designations

De Schelde S.32 - (Project) Twin-engined dive bomber; no details (??)

De Schelde S.33 - (Project) Single-engined, single-seat racing aircraft
- S.33: 1 x (??) hp (??) inline engine (3-blade prop); span 13.00 m
- S.33: Un-numbered 3-view drawing (28 Feb 1940) shows the layout*
-- * Low-winged monoplane; very short main u/c; cockpit set well aft
- S.33: Some say high-speed mailplane (perhaps suggested by size?)

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[1] Note: Powering ratings given are translated from pk. For the De Schelde S.6, Wright SR-1820-F2 Cyclone engines were probably spec'd (along with NACA cowls and 3-bladed, variable-speed Hamilton-Standard propellers) for easier comparison with KLM/KNILM's inservice DC-2s. (The KNILM being the NEI airline, Koninklijke Nederlandsch-Indische Luchtvaart Maatschappij.)

[2] Along with his brother Bas, Klaas de Geus van den Heuvel was an Amsterdam construction magnate. While the older brother became better-known for his art collection, Klaas became known as a sport aviator.

[3] The S.12 was built at the Bedrijfsschool, Vlissingen. Some sources say that the wooden wing structure was weakened by poor construction practices. As a result of this (or just of being overweight), the S.12 was incapable of carrying passengers. Nonetheless, Klaas de Geus van den Heuvel took delivery of the aircraft which he registered (for his initials) as PH-KGH.

[4] Designed to an IML specification, the ontwerp 163 jachtkruiser was derived from Fokker's G.1 twin-boomed heavy fighter. As the jachtkruiser operational concept faded from favour, the ontwerp 163 was re-imagined as a strategic reconnaissance aircraft.

[5] IML stood for Inspectie der Militaire Luchtvaart )or Military Aviation Inspectorate). Formed in 1935, the role of the IML was to coordinate between the LVA (Luchtvaartafdeeling or Army Aviation) and the LVB (Luchtvaartbedrijf or Technical Branch).

[6] The connect between the designation S.27 and ontwerp 76 is speculative. Ontwerp 76 was the first of four submissions for KLM's South Atlantic airmail route to Paramaribo in Suriname. It had a span of 24.00 m; 4 x Junkers Jumo 205 diesels; and carried 4 passengers + mail. Another submission was a trimotor with 3 x 1,000 hp Wright Cyclones, resembling an enlarged, mid-winged Pander S.4 Postjager.
 
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Hi,

S-8 small airliner with Jumo Diesel engines,data from 1935,project only
S-32 project for dive bomber
S-33 project for speed mailplane
 
The De Schelde S-33 was a single seat/single engined high speed aircraft
mentioned in "De Nederlands Vliegtuigencyclopedie-Schelde musch en Scheldemeeuw"
as a racer.

The first De schelde aircraft was de S-12, a four seat low wing tourer powered
by a 130hp Gipsy Major.

'S' indication stand for Slot the designer who before worked for Pander.
 
lark said:
The De Schelde S-33 was a single seat/single engined high speed aircraft
mentioned in "De Nederlands Vliegtuigencyclopedie-Schelde musch en Scheldemeeuw"
as a racer.

Thanks Lark. Obviously not Hesham's three-engined aircraft then!

lark said:
'S' indication stand for Slot the designer who before worked for Pander.

And before that, Theo Slot worked for VIH (Vliegtuig Industrie Holland). :)
 
The 'Scheldemusch'
and 'Scheldemeeuw'

never received an official De Schelde 'S' designation, only just their name.
 
Thanks for the corrections, Lark.

That makes better sense of the serial numbers. I noted that the De Schelde numbers follow on from Pander c/ns -- 47 was the last Pander E (c/n 24/I rebuilt). Then:

De Schelde S.12 c/n 48
De Schelde Scheldemusch c/n 49
De Schelde Scheldemeeuw c/n 50
De Schelde Scheldemusch c/n 51, 52, 53, 54, 55
De Schelde S.20 c/n 56
De Schelde Scheldemeeuw c/n 57

So, you've already told us that the S.12 was "a four seat low wing tourer powered
by a 130hp Gipsy Major". What the heck were the S.13 and S.14 ???
 
Actually, the S-4 design was the Pander Postjager.
Refer Wesselink, T and Postma, T, De Nederlandse Vliegtuigen, p. 87
 
Thanks Jos.

The overlapping Pander/De Schelde designations are all very confusing.

Lark said: "The military variant of the Pander 'Postjager' was the Pander S.4 'Militair' a planned medium bomber or long range reconnaissence aircraft."

http://www.secretprojects.co.uk/forum/index.php/topic,2742.0

I've assumed that the De Schelde S.4 designation would be applied to an on-going project (the Postjager having been abandoned with the collapse of Pander as an aircraft maker). De Schelde certainly intended to proceed with Postjager-derived military aircraft (see Hesham's post). Do you have confirmation that De Schelde also intended to continue with the Postjager itself?

Cheers
 
No mention of it in the Wesselink/Postma book.

Here is a list of the Slot designed aircraft that I have found in the book. The first number is the construction number and there is also the registration.

1 Holland H-1 not built
2 Holland H-1 H-NACD
3 Holland H-1 not built
4 Holland H-1 not built
5 Holland H-1 not built
6 Holland H-1 not built
7 Holland H-2 H-NACE
8 ?
9 ?
10 Pander D H-NACM
11 Pander D H-NACN
12 Pander D H-NACO
13 Pander D H-NACS
14 Pander D MLD P-1
15 Pander D MLD P-2
16 Pander D ML-KNIL P-501?
17 Pander D H-NACW, PK-SAB
18 Pander E H-NADI
19 Pander D ML-KNIL P-502?
20 Pander E PH-AEQ
21 Pander D H-NADL
22 Pander E H-NADV
23 Pander E H-NADW
24 Pander E H-NAEJ, PH-AJB
25 Pander E H-NAEV
26 Pander E PH-AEX
27 Pander E PH-AKA
28 Pander P.1 PH-AGM
29 Pander P.2 PH-AGN
30 Pander E PH-AFJ
31 Pander E PH-AFZ
32 Pander E PK-SAH?
33 Pander E PH-AFM
34 Mayer M.1 PH-2
35 Pander E PH-AFN
36 Pander E PH-AFP, PH-AIT
37 Pander E PK-SAJ?
38 Pander E PH-AFX
39 Pander E PH-AIA
40 Pander E PH-AIB
41 Pander P.3 PH-AIK
42 Pander Multipro PH-AIU
43 Pander Multipro PH-AIV
44 Pander Multipro PH-AIX
45 ? PK-SAW?
46 Pander Postjager PH-OST
47 Pander E PH-AJB
48 Schelde S.12 PH-KGH
49 Schelde Scheldemus PH-ALB
50 Schelde Scheldemeeuw PH-ALK
51 Schelde Scheldemus PH-AMA
52 Schelde Scheldemus PH-AME
53 Schelde Scheldemus PH-AMG
54 Schelde Scheldemus PH-AMH
55 Schelde Scheldemus PH-AMI
56 Schelde S-20 PH-ATY
57 Schelde Scheldemeeuw PH-ATM
 
Jos, you have anticipated me ;D I was just preparing a type list of produced VIH and Pander types!

To your list, I can only add a few glider types:

Pander PH-1 Zögling - 1930. A copy of the Stamer & Lippische Z-12 Zögling ('Pupil', designed by Alexander Lippisch). Replica at the Aviodrome.
http://www.aviodrome.nl/themapark/expositie/collectie-overzicht/M-W.asp

Pander PH-2 Mayer - 1930. Copy of German M.1 sailplane by Hermann Mayer. Used by ENZC club.

Pander SG-38 (Schulgleiter) - 1940?. Licenced Schneider DFS 108-14 for NSFK (555 built). http://www.abpic.co.uk/photo/1093296/

I haven't come across a PH- designation for the SG-38. Come to that, I'm not even sure if the PH-xx are actually Pander designations (Dutch gliders of the time all seem to be refered to by their PH- registration markings - for example, see: http://www.grunaubaby.nl/baby_in_nederland.htm )
 
Herman Dekker's 'The Complete Civil Aircraft Registers of The Netherlands since 1920' lists registration PH-1 as a Zogling RRG and PH-2 as a Mayer M.1. So, PH s a civil registration, not a Pander designation.
 
I remember that a few years ago a Dutch aviation magazine
produced a multipage article about unbuilt 'De Schelde' designs.
(no drawings,only descriptions)
Unfortunately I can't find the concerning mag.and text.
Is there someone who who can remeber it and who haves the magazine?
 
Jos Heyman said:
Herman Dekker's 'The Complete Civil Aircraft Registers of The Netherlands since 1920' lists registration PH-1 as a Zogling RRG and PH-2 as a Mayer M.1. So, PH s a civil registration, not a Pander designation.

Ah, so does that mean that (presumably like the SG-38) the licence-built Zögling and M.1 never received Pander designations at all?
 
A bit more about some De Schelde designs...

S.19 : two engined midwing 'jachtkruiser' crew of 4.Concept had much of the
Fokker ontwerp 193 who was much a G.1 loo alike.
S.22 : single seat highwing fighter with pusher prop driven by a R.R.II(?)
Two MG's and one canon in the nose,two in the wing.
S.24 : Isotta Fraschini Asso A 120R.CC.40 powered two seat combat aircraft.
High wing with pusher prop.
S.25 : two seat combat aircraft with gull wing and pusher prop.same engine as in the S.24.

abridged translation from an article by: F.Gerdessen in 'Luchtvaart' January 1998.
 
Hi,

the PH-3 was an open cockpit two seat light aircraft,a version
with 120 hp De Havilland Gipsy III,later modified to have an
enclosed cabin,only one was built.
 
Going through the Wesselink/Postma book I referred in an earlier post I came across (p. 18) the Carley S.1, a 1919 small aircraft. Slot was working with Carley in the early part of his career and this could be 'his' S.1 - although the book does not specifically state this.
The entire thing is, of course, complicated by the fact that Fokker used the letter 'S' extensively for its training aircraft.
 
Thanks Hesham,

That description fits the Pander P-3. I think we've established that PH-3 was simply the registration for a Zögling glider -- a German (Schleicher-built) RRG-1 according to Herman Dekker.
 
Verrry interesting, Jos.

What other Joop Carley designs are out there? I have Carley's L-11 biplane, the 1923 C-12 'Flying Bicycle', and the KLM 'Jumbo'.

The 'Jumbo' is too late to have involved Slot. But we know that the C-12 was developed into Slot's H.2 for VIH. So, going out on a thin limb ... if the Carley S.1 is also Slot's S.1, might Carley's C-12 have been Slot's S.2?
 
In my files,

there was also S-?,appeared in 1937 for de schelde light transport monoplane Project,maybe
taken the designation S-10 ?,only my suggesting.
 
The S.28 was appeared in Viegtuigtypes 1986/1.
 

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The S.28 was appeared in Viegtuigtypes 1986/1.

Thanks hesham. BTW, vliegtuigtypes just means 'aircraft types'. Your publication's name is Luchtvaart Kennis: Luchtvaart Historisch Tijdschrift.

So, does anyone have access to a copy of Luchtvaart Kennis 1986/01?
 
I've cleaned-up and corrected my original designation post. Alas no new de Schelde designations have come to light.

I had previously included the tekening nr. Jae-4301 and Jae-4302 in my listing. Since that nomenclature clearly refers to drawing numbers rather than actual designations, both concepts have now been removed.
 
Thanks to @boxkite, I have been able to correct and add slightly to the list in post #1

Details came from The Slot, Pander & De Schelde: Hollands vernuft in de lucht by Peter Knippels published by Lanasta, Odoorn, NL, 2025. 'Dutch ingenuity in the air', indeed! Well worth a look.
 
Please don't forget Jae 4301 & 4302 projects

Well, that is hardly likely, is it?

Just two posts above yours - in reply #31 - I explained why prior references to those tekening nummers had been removed from the designation lists.
 
De Schelde S.13 - (Project?) unconfirmed

De Schelde S.14 - (Project?) unconfirmed

De Schelde S.15 - S.18 - (??) hypothetical designations

In my files,and during period,1937,de Schelde had a project for monoplane passenger transport,
all mentioned is that,it was in February of this year ?!,source; Fokker in bedrijf 1911-1996.
 
De Schelde S.22 , S.24 and S.25 seems be variant of S.21

In a sense. I would describe these four types as closely related developments but not 'variants' exactly.

The S.22 was an alternative fighter to the same requirement as the S.21 but with a somewhat different layout. Both concepts featured pusher propellers (albeit driven by different engine types) but, whereas the S.21 had low-set wings, the S.22 was high-winged. That high wings and pusher prop arrangement was shared between the S.22 fighter proposal and the S.24 reconnaissance aircraft.

The S.25 is a little harder to picture. It shared engine installations with the S.24 and had the same span but is described as a having a mid-positioned gull-wing. That is an odd combo ... although Koolhoven played with similar wing arrangements during that time.
 
In my files,and during period,1937,de Schelde had a project for monoplane passenger transport,
all mentioned is that,it was in February of this year ?!,source; Fokker in bedrijf 1911-1996.

Also in this period,there was a project for two-seat light biplane,to know that,the
S.13 and S.14 maybe a real concepts, source; Afdeling Vliegtuigbouw.
 
Also in this period,there was a project for two-seat light biplane,to know that,the
S.13 and S.14 maybe a real concepts, source; Afdeling Vliegtuigbouw.

A 2-seat biplane light aircraft without a known designation - like your 1937 monoplane passenger transport - would be better discussed in De Schelde Aircraft Projects and Prototypes
-- https://www.secretprojects.co.uk/threads/de-schelde-aircraft-projects-and-prototypes.5276/

I'm not entirely sure what the rest of this was intended to mean.

to know that,the S.13 and S.14 maybe a real concepts, source; Afdeling Vliegtuigbouw.

"to know that..." Who knows that?

"... the S.13 and S.14 maybe a real concepts..." The word "maybe" is an admission of insufficient information to make a rational determination.

"source; Afdeling Vliegtuigbouw." If only 'Aircraft Construction Departments' could talk to us!

I assume that you are trying to cite Pieter van Wijngaarden's recently reprinted book Koninklijke Maatschappij De Schelde, afdeling vliegtuigbouw. If so, earlier this year, lark told you that your forgotten source on the "S-13 and S-14" [sic] was incorrect. In the same post, lark made clear that van Wijngaarden was simply speculating about S.13 and S.14 as possible projects.
-- https://www.secretprojects.co.uk/th...ojects-and-prototypes.5276/page-3#post-753840

So why now parrot back lark's source as if his previous refutation had become some kind of proof for your claim?

Please observe the differences in logic between 'possible' (ie: an absence of contradiction) and 'probable' (a higher likelihood). The 'possible' is what can (or can't) happen. The 'probable' is that which might be likely (to whatever degree) based on evidence and/or reasoning. And do try not to confuse the latter with 'I think it might be so'.
 
So why now parrot back lark's source as if his previous refutation had become some kind of proof for your claim?

The last two projects are not from my claiming,I mentioned the sources,so
we can consider them a mysteries,not solved ?.
 

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