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Oct 25, 2015, 01:07 PM
71% of the world is runway . .
Bart83's Avatar
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Build Log

Dornier Do24K1 , 1/10th scale ( Maiden Flight report & video )


Well here it finally is ,the start of my Dornier Do24. The project already has quite a bit of history itself as some of you may know. I will tell about that later on in this post.

This build will also be a tribute to all Dutch crews who served on this aircraft during the defence of the Netherlands East Indies against the Japanese invader. A part of history often overlooked or ignored.
I hope that this build will give the Dutch navy crewmembers some time in the spotlight and more people learn about the Dutch effort during the early stages of war in the pacific theatre.
At first some background on the real thing. This aircraft has an interesting history.


The Dornier Do24K for the Marine Luchtvaartdienst (MLD , Dutch naval airserice)

Since 1926 the MLD was using the Dornier Wal flying boats to patrol the vasteness of the Dutch Indies, with distanses streching out sometimes more than from one side of Europe to the other. The Wal's performance was adequate but the airplane soon got outdated. In 1934 the navy started an investigation into a succeeder for the Wal.
The new plane had to be bigger, equipped with three engines, none of these to use pusher propellers, a maximum speed of 315 km/h, be of an all-metal construction and comforatble enough for long distances.
With this specification in hand the navy went to a number of company's for there awnser on the requirements such as Fokker , Sikorsy and Dornier. The latter was the only one that came up with a design which could be ready in time. In 1935 Dornier came up with design P14 and by the end of that year a detailed model was ready to show to the Dutch navy. In 1936 the first contract was signed for the delivery of 6 aircraft. At this time Germany was very busy with re-arming the Luftwaffe so the german goverment had no interest in giving away production capacity for a dutch navy flyingboat.
The first order was thus placed via the Swiss Aero-Metall A.G. in Zurich. Aero-Metall was the Swiss Dornier factory and she handed the order over to a Dornier daughter company, A.G. fur Dornier Flugzeuge based at Altenrhein, on the Swiss side of the Bodensee.
Do 24 V3, the first of the Dutch boats, took off from Lake Constance on 3 July 1937, with the second Dutch boat, Do 24 V4 following soon after. As the Dutch required that their flying boats use the same engines as the Martin 139 bombers in use in the Dutch East Indies, they were fitted with 887 hp Wright R-1820-F52 Cyclone radial engines. Test results were good, with the new flying boat proving capable of operating from extremely rough open seas, and the Dutch placed an order for a further 12 Do 24s on 22 July 1937.
The Netherlands was enthusiastic about the new flying boat, and planned to purchase as many as 90 Do 24s. Of these, 30 were to be built by Dornier (with all but the first two prototypes assembled by Dornier's Swiss subsidiary based at Altenrhein). The remaining aircraft were to be built under licence in the Netherlands by Aviolanda at Papendrecht. Of these aircraft, all but one of the German and Swiss built aircraft and the first seven Aviolanda-built aircraft were to be Do 24K-1s, powered by the original R-1820-F52 engines, while the remaining aircraft were to be Do 24K-2s, with more powerful 1,100 horsepower R-1820-G102 engines.
Thirty-seven Dutch- and German-built Do 24s had been sent to the East Indies by the time of the German occupation of the Netherlands in June 1940. Until the outbreak of war, these aircraft would have flown the tri-color roundel. Later, to avoid confusion with British or French roundels, Dutch aircraft flew a black-bordered orange triangle insignia.
During the defence of the Netherlands East indies a heavy task lay upon the flight crews. They had to fly reconnaissance missions , lay mine's , drop bombs and preform rescue operations.

Original source : Dornier24.com , The Dutch naval airforce against Japan by Tom Womack , Dornier Do24 , herinneringen aan een legendarische vliegboot by Prudent Staal & Pieter van Wijngaarden


During this build thread i will try to write some about individual missions from time to time. There are quite some heroic stories to tell.
This build log will be mix between building an airplane and sharing some history.


The model :


I got intrested in the Dornier Do24 when i was building my Short S.23 empire flyingboat some years ago. When i was reading about the evacuation of Java i read about the role of the Do24 played in that also.
By then i was exploring to learn cad. When i was ready to start a new design i started work on this aircraft. During the design period it almost became an obsession for me to have everything as accurate as possible. Much time was being spend by digging through manuals , looking at pictures and trying to convert that in my 3d model.
I got help from the Dornier archives in Friedrichshafen , Germany. They provided my with an original drawing wich i could use to calculate the hull sections. Understanding how this drawing was to be used was a challenge on its own.
After some time i was happy with the look of the 3d model and i started with the design of the construction. During the design period i met Jim (Parkcityskier) here on Rcg. He showed much intrest in the project and we decided that he would build the prototype. He did an amazing job on this and the aircraft looked stunning. Sadly my design proved overingeneerd and the model was to heavy. Also we had problems with the cg and on its only flight it was too nose heavy.
With all lessions learned from this prototype i started the redesign. By now i had more experience in designing model aircraft and i feel this v2 design is far superior to the first design. The model will be build using lasercut parts , both balsa and ply. The fuselage will be build in two halves with the split vertical so a flat workbench will ensure a straight and true build.

Both Jim and myself will be building a Dornier this time. I met Jim earlier this year when he was in the Netherlands. I had arranged for us to have a look inside the Dornier Do24 on display in the Dutch militairy museum and i handed him the plans for the model in person.
Jim will start a build thead also. We both have a different planning for the build so this will make it intresting to follow both threads.
The actual build progress will start in a seperate post. I plan to start the build with the tail.


I would like to thank a number of people in advance for there contribution the the project already :


Jim Stuart(Parkcityskier): for his imput on the design and showing unbelievable perseverance while building the v1 prototype

Gary Morgan (GLM) : For his help in learning me all about the produtcion proces and providing me with the beautifull balsa lasercut parts.

rc-europe.eu (Sebastiaan van Buiten)
: For providing my with the beautifull Lasercut plywood parts and being willing to take the model in production if it has proven to be airworthy

Prudent Staal : For inviting me over and sharing lots of his knowledge about the Dornier.

Rolf Breitinger : For awnsering all my questions about the Dornier Do24T he has build. His help on technical issue's was very welcome.

Alfred Staarman : For making it possible for Jim and me to visit the Dornier Do24 on display in the museum.

Arthur Shoenknecht : For making my 3d model work in the Rc Sim Aerofly RC7. Link to download the model

And all those who contributed with help , feedback and sharing idea's during the design , build and testing of the v1 prototype.



I hope you all will enjoy this thread. Please feel free to ask any questions , share idea's or give feedback.

Kind regards ,

Bart




Video of the Dornier Do24K in service of the Marine Luchtvaartdienst :

Dornier Do24K (3 min 22 sec)
Last edited by Bart83; Aug 26, 2019 at 02:35 PM.
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Oct 25, 2015, 02:28 PM
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RiBell's Avatar
Bart:
Cool it's started
Will be watching with great interest.
Rick
Oct 25, 2015, 03:45 PM
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Great introduction, Bart. I'll be starting my build and thread by the end of November. The only comment that I would have on the history of the airplane was the requirement that it be comfortable enough for long flight times. Based on my sitting in the real aircraft, I would have to congratulate those pilots and crews for their perseverance . I understand that it was described by some who flew the aircraft as like being in a submarine! With low ceilings, a watertight door every so often, and a tendancy for the nose to be mostly submerged in rough water landings, I can understand the comment. Based on the limited flying that I did with the prototype model, I think that the version 2 is going to be a fine flying airplane and a real winner this time.

Jim
Oct 25, 2015, 03:56 PM
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RiBell's Avatar
Quote:
Originally Posted by parkcityskier
I'll be starting my build and thread by the end of November.
Jim
Jim:
Looking forward to your progress as well.
Rick
Oct 25, 2015, 03:56 PM
HJG
HJG
HENRY
Bart,
Looks fantastic cad work, wish you a successful build and superb flying model.
Starting to make your Dornier Wal look an easy build
Oct 26, 2015, 08:47 AM
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Wormboy's Avatar
I'm signed up to watch this baby come to life.
Well done Bart, I know it must be a great feeling to finally put some wood together after all this time.

And kudos to you too Jim, building v1 and then coming back for a second round!

Bart, do you have a specific aircraft in mind (is it the x24?) and can you tell us of its service and ultimate fate?

Mat.
Last edited by Wormboy; Oct 26, 2015 at 08:54 AM.
Oct 26, 2015, 10:28 AM
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Mat, when you see the DO-24 in the air it is like no other. Even with the problems that we had with the V1, I knew that I wanted the airplane. Bart did a great job on the redesign and we both learned a lot on the prototype build so it was a very easy decision for me to build the Dornier again.

Jim
Oct 26, 2015, 12:20 PM
71% of the world is runway . .
Bart83's Avatar
Thread OP
Thanks for the kind words guys !

@ Matt , i have not decided yet but im leaning towards the ''X24'' , just love the noseart.

Added a link to download the Dornier Do24 for Aerofly RC7 in the opening post. ( in the last line of the ''thanks'' chapter) , please note that is takes very long for this model to load.

Cheers,

Bart
Last edited by Bart83; Nov 03, 2015 at 01:32 PM.
Oct 26, 2015, 01:00 PM
71% of the world is runway . .
Bart83's Avatar
Thread OP
Started by sorting the lasercut parts for the tail. Its fun to knock out parts from there sheets. Also checked part fit and im very happy with how it all goes together.

A big difference with the v1 prototype is that on this new design many things have to be figured out by the builder. I figured that only an experienced builder would be intrested in building this aircraft.
Usually every model builder has his own way of doing things.
It seemed more appropriate to make room for this rather then to chew everything out to the limit like i did on the v1 prototype. An example of this are the tail servo's. . . .

Cheers,

Bart
Oct 26, 2015, 01:16 PM
Registered User
RiBell's Avatar
Bart:
Looking at your elevator bearings. I don't see the grease fittings

Based on the elevator parts as I see them. It looks like the hinge line is back from the leading edge making a scale hinge line. Is it the plan to have a removable hinge wire?
Rick
Oct 26, 2015, 01:43 PM
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GLM
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Great start Bart!

Looking forward to following along during the build.

A Seminal Work!

Cheers!

Gary
Oct 26, 2015, 03:31 PM
71% of the world is runway . .
Bart83's Avatar
Thread OP
@ Rick : sorry about the grease fittings maybe i'll make the elevators removable.

@ Gary , thanks !

Cheers,

Bart
Oct 26, 2015, 03:32 PM
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Bart, it goes together pretty fast when you have cut parts that fit together so well. Your thread is making me eager to get going on mine but it will be another few weeks until I can get going with it. Since I will be starting with the fuselage and doing the tail last, it will be interesting to see where we will meet, in the middle of the build.

Jim
Oct 26, 2015, 04:22 PM
71% of the world is runway . .
Bart83's Avatar
Thread OP

Story about the X-29


A while back i was contacted by a very kind fellow from the Netherlands named Michael Klaversteijn.
He told me he had read about my the Do24 project somewere on the web and that he had great interest in it.
His uncle served on the X-29 during the defence of the NEI. Micheal's uncle is Flight Lieutenant P.L.G. Adriani.

Michael asked me to post an article he wrote about the X29 in my thread wich i will do gladly offcourse.

Kind regards ,

Bart

Article :

The story of the last flight of the Dornier flying-boat X-29

This story is based on the report of the corporal AJCBrekelmans.
He was technician/gunner on board the X-29, a flying-boat of the Royal Dutch Navy.
This Dornier flying boat was a unit of Aircraft Group 6 (GVT6) in Dutch East Indies.
From December 1941 till March 1942 the crews of the naval wing (MLD) of the
Royal Dutch Navy fought a japanese enemy with great determination and courage.

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A dornier24 flyingboat on a reconnaissance flight over the dutch east indies.


The japanese attack on Borneo.

After the raid on Pearl Harbor the Japanese army and navy continued their assault
on south east asia.
The oil-rich island of Borneo in the Dutch East Indies was one of their prime targets.
After a brief and fierce battle the cities Tarakan and Balikpapan on the east coast of
Borneo were taken during January 1942.
The Japanese continued the encirclement of Borneo along the coasts of the island.
Groundforces headed on foot and by bicycle through the jungle along the east and
south coast to the city of Bandjarmasin in southern Borneo.
A landingfleet sailed along the coasts of Borneo to attack the city from the sea.
At the beginning of February 1942 Bandjarmasin was the last city in dutch hands.
The city was defended by small KNIL force of the dutch army.


The actions of GVT 6.

The main task of GVT 6 was to observe the Japanese advance along the west
coast of British and Dutch Borneo.
In January 1942, the Dorniers X-28, X-29 and X-31 of GVT 6 flew day and night.
The positions of the approaching enemy were continually passed to the navy
headquarters in Bandung on Java Island. Kuching’s airstrip on British Borneo was
overrun by the japanese army halfway January 1942.
For 3 days GVT 6 then attacked the airstrip till it was bombed beyond repair.
On January 24, the X-29 evacuated russian sailors from the torpedoed s.s. Perekop
from the Natoena islands north-west of Borneo.
On January 25, the X-29 flew in rice for the starving people of the Tambalan islands
On January 26,the X-29 set fire to japanese troopship off the coast of Pontianak.
In this action one crew member was injured and one was killed by enemy fire.
By the end of January 1942, as the fall of Borneo was approaching the flying-boats
retreated to Java.


The Dornier 24 flying-boat

The dutch navy needed a long-range flying-boat to succeed the Dornier-wal flyingboat
for operations in the dutch east indies.the Dornier flying boat 24K was built
under dutch specifications by the german Dornier factory in Switzerland.
The so-called X boat was a big 3 engined and very seaworthy flying boat.
The aircraft was designed for flying long patrols in the vast archipelago.
The crew of 6 received special training and had specific tasks on board.
The members worked closely together during the weeklong patrols.
The X-29 was damaged during confrontations with the enemy over Borneo.
The ongoing war conditions had worn out the aircraft as well as the crew.
Early February 1942 the X-29 had seen major repairs and overhaul


The fall of Bandjarmasin

Lieutenant Colonel Halkema was ordered to defend Bandjarmasin against the
japanese attackers. Nevertheless Halkema pulled back his troops on 9.February
and left the city at the mercy of the enemy.
In the morning of 10.February Bandjarmasin was occupied by a few hundred
Japanese ground troops.
During the intake war crimes were committed by the japanese officers and soldiers.
Residents including Mayor Mulder of Bandjarmasin were assaulted and slain.
Yet during the war Halkema had to justify his actions before a military court martial


The evacuation mission

The navy leadership on Java ordered the MLD evacuation operation.
On short notice 3 Dorniers and crews were assembled.
Flight Lieutenant P.L.G. Adriani received orders to carry out the mission.
Lieutenant Adriani was the pilot commander of flying-boat X-29.
During the first week of February 1942 there were fierce air battles over Surabaya.
The city of Surabaya and nearby naval airbase Morokrembangan were daily
bombed by the Japanese army and naval Air Forces.
After a week of fierce airbattles Java airspace was under Japanese control.
Of all dangers of an evacuation mission in occupied Borneo there was the hazard
of an encounter with a superior enemy in the air.


The flight to Bandjarmasin.

It was decided to carry out the evacuation during the night.
In the afternoon of February 10. 1942 the 3 flying boats took off from the water in
the darkness and set heading for japanese occupied Borneo.
The flight from Java to the south coast of Borneo took them over the vast Java Sea
and lasted about two and a half hours.
In the dark the three Dorniers circumnavigated the monsoon thunderstorms and
headed for the estuary of kali (river) Barito on southern Borneo.
There, a dozen miles inland near the port of Bandjarmasin was the meeting point
with the refugees from the city.


The evacuation

The refugees would be taken aboard by the flying boats in the vicinity of the port of
Bandjarmasin.The 3 flying-boats had to be landed on the river.
Contact had to be established with the evacuees on the shore of the river.
Commander Adriani flew the X-29 over the area to look signs of the evacuees.
However there were no signals seen instead the X-29 was heavily machine
gunned.
The area was occupied by japanese troops and the enemy was prepared for the
arrival of the flying-boat ...
By immediately climbing into the monsoon clouds the X-29 escaped the shelling.


The flight back to Java.

The X-29 was hit by the groudfire and immediately returned to Java.
Observer Jan de Vries in the nose turret was hit in the leg and was injured.
The flying-boat had sustained unknown damage.
Finally around 10 o'clock in the night came the island of Madura, in sight.
There at the height of the western tip of Madura, two of the three engines failed.
Were fuel-tanks hit and leaking ?
Did the engines stop due to damage because of the shelling?


The emergency landing.

The X-29 was loosing altitude quickly
Suddenly an emergency landing had to be made at the sea at night.
A night landing is difficult because lack of reference of height.
Especially above water altitude is difficult to estimate.
On top of that rate of descent could not be controlled due to a double enginefailure.
Added to that, the crew was exhausted by the long flying under war conditions.
All these circumstances made the emergency landing particulary difficult.
The landing in the waves was so ill fated that aircraft immediately started to sink.


The rescue.

Despite a broken wrist corporal Brekelmans managed to climb out of the tail turret.
He crawled over the hull forward and found commander Adriani lying injured in sea.
Brekelmans saved his commander from the water and laid him on top of the wing.
Corporal gunner Bert Ostayen also managed to get out of the sinking Dornier.
The 2 corporals pulled out a life raft and launched it into the high sea.
Paul Adriani was laid in the small boat.He was unable to speak or to move.
The men had to wait for the next day and their rescue.


The disaster.

3 Crew members in the X-29 were unable to get out of the aircraft.
The unlucky young men were trapped inside the fast sinking flying-boat.
These crew members were:
Sergeant pilot Pieter de Ru
Sergeant observer Jan de Vries and
Corporal telegraphist Jan Woltjes.


The aftermath.

The next morning two Dorniers searched the area for the lost flying-boat.
The last position of the X-29 was known and the three survivors were quickly found
and rescued from the sea.
Paul Adriani died in the evening of 11. February 1942.
He is buried in the military cemetery of honor Kembang Kuning in Surabaya.
After the surrender of the Dutch East Indies Dré Brekelmans and Bert van Ostayen
ended up in a japanese concentration camp till the end of the 2nd world war.
After the war Dré Brekelmans continued his career in the Royal dutch Navy.


For my uncle Paul Adriani and the crew of flying-boat X-29

Michael Klaversteijn
February 2011

Literature:
"Wings of the fleet" by L.Honselaar (1950)
"Heroes hares and dogs" by C. van Heekeren (1969)
"Scouting and guarding" by N.Geldhof (1978)
"The dutch naval air force against Japan" by T.Womack (2006)
"The Borneo affair" file in the National Archives

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The last known position of the X-29


For his actions Paul Adriani was posthumously awarded the flyers cross :

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Last edited by Bart83; Oct 27, 2015 at 04:51 PM.
Oct 26, 2015, 04:49 PM
EB-66C Team Member
J Morgan's Avatar
Good reading, very interesting. Thanks Bart.

J


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