PSS DH108 SWALLOW

[Matt How]

Having got the slope diesese early this year and with a growing collection of slope rockets, My dad and i stumbled upon the PSSA website. Spured on by his love for old supersonic jets, he found a plan for a dh108 online, plan purchased. Then as he would do redrew it on autocad with a few modification of his own the beast was drawn and the task of cutting out what seems to be an endless pile of ribs and formers, she slowly takes shape......

the wing plan after the rh wing was complete he has the task of drawing the lh wing plan.

thourght Dbox and carbon spars was the way to go. this was very tricky and this wing alone was the best part of 3 weeks.

this it rh wing route/ air intake which was made using an aluminium jig to ensure it was straight.

Days of mik taking , as i wasnt sure whether it was a jet fuslage or the hindenburg.lol

this a bad pic but it has working bomd bay doors which house the launch handle, had to construct some complex hinge system to operate them.

#

the fin , which i insisted on a scale hinge took him 2 weeks to get right lol

The Man himself who is responsible for this beast, bit camera shy lol

Once the model started building more we relise just the scale of what we created, she is going to be a monster about 90 inch wingspan. Will update with new photes as the build gets on.

[Tony Bennett]

lovely looking build gentlemen.

[Erfolg]

I am not sure that the swallow had a bomb bay. I am not certain that it was supersonic either.

But as a model, excellent.

Well done.

You will need Eric Brown as your pilot, it will then be in safe hands, even if they are only from Latex.

Again, looks good, excellent!

[David Gilder]

Very impressive Mad!

Looking forward to seeing this fly at one of the PSSA events this year.. along with your F16 seen on page 2 of my thread!

I will be following this build with interest so please keep it updated regularly!

Dave

[Matt How]

The original didnt have the doors, but we didnt really want a huge hole in the bottom, got a ring of lights for the tailpipe and gunna experiment with some whistles for a bit of noise.

[Former Member]

[This posting has been removed]

[Tim Mackey]

Great stuff, and this is gonna be a great addition the growing collection of PSSA models - have you and dad joined up - its free, and we would love to have you join us for the years meetings ( schedule on the PSSA website )

[Martin Harris - Moderator]

Posted by Erfolg on 14/01/2013 20:04:23:

I am not sure that the swallow had a bomb bay. I am not certain that it was supersonic either.

Wasn't it the first British aircraft to go supersonic?

[Former Member]

[This posting has been removed]

[Martin Harris - Moderator]

I don't believe all 3 broke up through trying to go supersonic although all crashed with fatal consequences.

Geoffrey DeHavilland's final flight in the second prototype was certainly while investigating high speed handling and I believe there was speculation that he did exceed Mach 1 before it broke up.

The third example which had been modified to prevent the high speed oscillation problem that probably killed GdH was the first British aircraft to break the sound barrier (on 6th September 1948) piloted by John Derry. This one was lost later due to probable failure of the oxygen system.

The first prototype was the last one lost when during low-speed sideslip and stall tests, it failed to recover from an inverted spin.

[Erfolg]

I think in the case of the Swallow, it was thought it might have gone through the sound barrier whilst diving 10,000 feet. From a record braking stand point, no record was broken as it did not conform to any of the then requirements. From what I have read, the instrumentation indicated it might, but showed 0.985. I seem to remember from what I have read that at this point the aircraft went out of control with Eric Brown at the controls. It had the power,not the aerodynamics it would seem.

I think it was a DH 110 with John Cunningham that is officially the first UK plane to break the sound barrier, again in a dive.

Still, it will be a fine model, very elegant to look at. A slimmed down Me 163, which also got into the same region, with similar results.

[Martin Harris - Moderator]

I wasn't around then but all the sources I can find on the net confirm it was John Derry flying the DH 108 which acheived the first official British supersonic flight.

[Erfolg]

I think it is thought it may have exceeded the sound barrier, rather than did. All the pilots seemed to loose control as the machine reached about 0.95. If it did it was not under control.

You have to remember that there was a public expectation, which translated into a Governmental hope, that Britain would also follow the lead of the USA and have a supersonic aircraft. In this environment we all wanted to believe. The public was fed hints, about the UK capability, could the Javelin go supersonic, perhaps the Hunter. Although we were told and saw demonstrations of the 110 going supersonic until a crash at Farnborough, changed official policies. This was a time of bluff with the Warsaw pact countries and the West, where there were secrets and then there were secrets , misdirection, all vying to gain a physiological and real real advantage, this was true of all participants. Even now sorting fact from fiction is not that easy.

It is known however that DH 110 could exceed the sound barrier, again in a shallow dive and more importantly under control. It was John Derry who flew the Swallow not Cunningham(who was a DH test pilot also at DH) as i have written.

Do not get me wrong, I truly like the shape of the aircraft. Also the bravery of all the pilots had to be admired. Particularly those who knew their were issues with the aircraft at high speed. Yet they pressed on with their job.

It could be that the Swallow convinced DH, that Comet was best built in a conventional format, rather than as a wing, as had been considered.

[Martin Harris - Moderator]

We all know that history is bunk but is there evidence to challenge the generally held belief that the DH 108 was the first British supersonic aircraft - or is this just (perhaps well-informed) speculation?

I'd be intrigued to know if you have inside information about this, Erfolg.

[Bob How]

Hi this model is the last of the three prototypes I chose it because of the modified nose and canopy which Gives it a sleeker look, it also looses the Handley page stall slats and the anti spin parachutes pods from the wing tips, the wing sweep was also increased from 43 deg to 45 deg as the ministry As I live in Watford it probably flew over my house when I was a nipper.

An Interesting fact this particular model crashed on 35th feb 1950 over Brickhill in Bedford killing Sq Ldr Stuart Miller Rowland, it was reported to have suffered structural failure of the left wing and damage to an oak tree can still be seen in the woods where it came down and the left wing was recovered from a nearby field.

[Erfolg]

I think you need to look at the other way, where is the official claim that the aircraft exceeded the speed of sound.

We have all read that the as an example that the Javelin was thought to be capable of supersonic flight, yet the quoted figures are 0.91.

I certainly not seen a definitive claim, other than it might have exceeded the speed of sound, whilst in an uncontrolled dive.

It was not supersonic in the way that Bell X1, FD2 or the F100.

It was not supersonic in the way that the DH110, in a controlled dive.

It was probably more akin to a Spitfire in a uncontrolled dive, where very high speeds have been claimed, although never truly verified.

I personally do not think it really matters, in any practical way, it was one of the blocks upon a better understanding of the requirements for controlled and sustained supersonic flight.

Which did lead to the UK's first truly (operational) supersonic aircraft the EE Lightening.

[Gordon Bushell]

I've been to hear Eric Brown talk a couple of times, and most interesting he is too.

From my memory of his description of flying the swallow after Geoffrey de Havilland was killed, supersonic flights would have proved fatal.

[Gordon Bushell]

Eric Brown also described one of his predecessors in the high speed flight's dive with a Spitfire, where the plane suffered failure of the gearing between engine and prop, and lost the prop. The pilot blacked out as the cg shift pulled the plane out of it's dive, and awoke at almost the height from which the dive commenced. He then made a successful landing. Apparently the wings had gained some sweep, and there were large gaps at the leading edge of the wing roots.

[PatMc]

Whilst testing VW120 on 6th Sep 1948 John Derry entered a dive from 45000ft at 0.85 Mach. He lost control at 0.94 Mach, there was a nose down pitch & the dive steepened. The indicated airspeed reached 1.04 Mach before it began to slow, Derry regained control about 0.98 Mach & leveled at 0.94 Mach at 23000 ft., his constipation now cured.
Instrument error was calculated which showed that a true airsped of 1.02 Mach had been achieved. It was the first British, the first ever jet aircraft & the first aircraft capable of taking off & landing under it's own power to break the speed of sound.
The same aircraft exceeded Mach 1 once more during a test flight on 1 March 1949, again out of control before it recovered.

Ref: British Experimental Jet Aircraft, Barrie Hygate.

PS I made up the bit about constipation.

 

Edited By PatMc on 15/01/2013 16:16:42

[Turbycat]

I think it is looking like a beautiful model. I like the look of the Swallow very much. Would love to see one with the small JetCat P20 turbine in it

Andy

[Erfolg]

Patmac

The descriptions provided, do not paint a picture of a viable supersonic aircraft, in my opinion.

[Martin Harris - Moderator]

But as Pat points out, the Swallow was a "proper" aeroplane, not an air launched guided rocket like the X-15, which was capable of sustained transonic flight with the occasional brief and rather "exciting" excursion into supersonic flight.

That's good enough to qualify as a supersonic aircraft in my view.

[Erfolg]

Why have a go at the X15, it did what it was supposed to do well. Although I suspect it is the X1 you are really thinking of, again did what it was supposed to do.

If taking of and landing with supersonic capability is the criteria, then the Douglas Sky Rocket, just about fits the bill.

There was nothing intrinsically wrong with the DH 108, other than if the sound barrier was the goal, it perhaps did not truly deliver. As a research vehicle to aid getting to dependable supersonic flight, it played its part, in building an understanding with respect to what matters etc.

Our first true supersonic in service aircraft the EE Lightening, was built on the back of all the DH Swallows and there ilk. It takes nothing from the 108's that they were are not as capable as an F16. For its time it was a fine aircraft (all 3), with limitations.

[David Gilder]

Come on now everyone.

I'm not one to throw a bucket of water over a very interesting discussion, but this really isnt the place to be doing it!

It has taken Toms thread from a build blog to a to and fro debate.

Could I kindly request that if you wish to continue this exitable dicussion about wether the Swallow was a supersonic aircraft or not, someone sets up a new thread.

Please leave this thread for what it was opened for, A build blog of what will no doubt be a fantastic PSS model .

[request over]

[Matt How]

Dad and i have had the same discussion for hours dave. lol