Sopwith Triplane mishap at Old Warden today
 

At the end of its display the Shuttleworth Trust's Sopwith Triplane undercarriage clipped a fence and the aircraft ended up on its nose. The pilot was physically unhurt (but probably p***** off). The wind had veered round during the display and so the approach was sideslipping from the right of the landing strip.

The first image is a few seconds after the event. The second about 45 minutes later.

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Sopwith Triplane mishap at Old Warden today
 

...any landing you can walk away from...

Sopwith Triplane Crash Video
 

Shame. Looks to me like it hit a steel gate rather than a fence. Glad the pilot was alright.

Looks like the left wheel caught that wooden fence post to me. Very sad but the main thing is the pilot's unscathed...

Agree,

Seemed to appear to strike the fence.

Out of curiosity what were the "Old Bill" doing on the scene, breathalysing the pilot or doing something useful? :)

What it hit.
 

My only qualification here is to have been involved in fencing in rural Australia in my youth. What the Triplane hits is a gate post, and these are substantial and very firmly rooted in the ground. Designed to stand up to persistent leaning and shoving by cattle, they will easily win in any conflict with WW I aeroplanes; steel might have bent.

(Actually, I was involved in putting in a fence around a pistol range on a disused landfill tip. The power auger drilling holes for strainers and fence posts a couple of times broke through into an abandoned fridge.)

Very glad the pilot was OK.

Any aircraft crash site immediately becomes a crime scene. So therefore the civil police have to be involved from the outset. This incidentally also includes military aircraft. Once the police are satisfied that no 'crime' was committed, the incident is then handed over to the AAIB for their investigation.

Looks like he was a little low so he to went to add power and all that happened was a load of smoke from the engine??

Not low, just off to one side of the landing strip. Those fences run parallel to the strip. A pity he hit one of the more sustantial posts but good news that nobody was hurt. We won't be seeing that bird in the sky for some time to come, great shame....

Excellent news that the pilot was unharmed. I liked the very British understatement of the PA announcer on the film clip when the aircraft tipped onto its nose, a simple 'Oh dear'. I can think of a few other countries where there would have been much shrieking and babbling. Top marks that man :D

He also seems to come from glass is nearly full school of optimism as he can be clearly heard telling the public that the aircraft will be 'back in the air in no short time I imagine'. I'd be very interested to know what the estimated time will be for repairs to airborne

Nothing to do with piloting skills. Smoke can be seen from engine prior to mishap:ASN Aircraft incident 29-JUN-2014 Sopwith Triplane Replica G-BOCK

That's it, then, no need for the AAIB............thanks SS...

He talks about the problems landing with rotary engines here (and how to control them in part 1):

https://www.youtube.com/watch?v=kOZyV4hDTGY

Dear me, sharkey, smoke coming from the engine!

Forgive my sarcasm (or not, as you wish) but smoke and clearly heard exhaust noise suggests to me the the engine was working just fine. It certainly looks and sounds exactly as it should from that video.

Are you familiar with the operation of rotary engines?

" Forgive my sarcasm (or not, as you wish) but smoke and clearly heard exhaust noise suggests to me the the engine was working just fine. It certainly looks and sounds exactly as it should from that video".


I do have a basic idea how rotary engines work. I'm just gullible, the article suggested the smoke was abnormal, so I just accepted that.

I have absolutely no knowledge of the operation of rotary engines so hopefully you can educate me?

In the clip by Background Noise, Dodge Bailey says that the fuel is completely cut during the approach and the fuel cock is only turned on again when "crossing the fence". Could you please tell me why this has to happen? Is it not possible to idle a rotary? In the crash video, does the smoke appear when the fuel is re-introduced to the engine? What does he mean by "hold it off on the blip switch"?

Sorry for all the questions but am just interested. Will be visiting Old Warden in the next few weeks.

Its very unlikely that the AAIB would investigate an incident such as this. The majority of their reports each month are based on information submitted by the pilot. They would only usually investigate if someone dies or its a public transport type of aircraft.

a rotary engine has no throttle and only one magneto.

you can control the engine speed by "blipping" the magneto, that is switching it off for periods then on again.

the engine slows while the magneto is off and surges back to full rpm if the magneto is left on and firing.

you don't realise just how much of an advance the modern aero engine is until you've seen a rotary engine in operation. :E

Thanks W8. Very interesting.

It fits the criteria of a Reportable Accident, therefore the AAIB will open a file on it, and their summary of the details of the event will appear in due course in a forthcoming issue of the monthly bulletin.

What they are very unlikely to do is to conduct a field investigation with all that that entails.

W8 - partly true. If anyone actually took the time to watch the youtube video I linked to earlier, the mishap pilot himself describes the way rotary engines are controlled for landing and mentions the Sopwith Triplane.

No! That's exactly the point!

A rotary behaves rather like a simple model glo-plug engine in that it either runs or it doesn't according to mixture. There's no throttle, it's either on or off.

Due to the considerable inertia of that big wooden prop and several cylinders plus crankcase all whirling round it has huge inertia so stopping the combustion does little to slow the rotation.

There are two ways of robbing a rotary of it's 100% power, either shut the fuel (lever) off or cut the magneto (blip switch). Thus to achieve an average power level between 100% or more than zero the pilot needs to modulate the engine between "off" and "100%" by means of either the fuel lever or the magneto switch.

Hence "blipping". I assume one sets up a high approach with the engine inhibited - i.e. dead via the blip switch or fuel control at "off", which approach is reduced by the characteristic sideslip but interspersed with a burst of engine (by necessity at 100% intermittently - or as soon after restoration of sparks or fuel the damn thing chooses to respond) Watch videos of rotaries taxying - blaaaa! pause - Blaaa! pause, Blaaaa!

It's a pretty blunt way of controlling power by today's standards and as described in the video above each individual engine seems to have it's own way of responding - or not - or maybe.

Even so, smoke and engine noise on short finals shows that the engine is trying to light up again if not actually giving its all just yet.
It is a two-stroke after all. If it is running it'll smoke like hell - and smell like Heaven, of course!

Do the Tiger Club have their Stampes still? They were fitted with a basic "injector" fuel system that was allegedly based on Sir William Cobham's full inverted system (1920's) , derived from a rotary set-up using a fuel lever and an air lever only. You changed over from the nice but blue-side-up only carburettor to this devious two lever contraption that just gave you engine on or off - and then only if you had fuel and air levers precisely balanced (fugall power if you didn't) , tho regardless of attitude which made the Stampe nicely aerobatic. Still, it sure was a bit of a blunt instrument and one that astonishingly had lasted well into the late '80s when I last saw it. It impressed the heck out of me, I can tell you!

Magenta Line it isn't!

Although a conventional carburetor, with the ability to keep the fuel/air ratio constant over a range of throttle openings was precluded by the spinning cylinder block, it was possible to adjust the air supply through a separate flap valve or "bloctube". The pilot needed to set the throttle to the desired setting (usually full open) and then adjust the fuel/air mixture to suit using a separate "fine adjustment" lever that controlled the air supply valve. Due to the rotary engine's large rotational inertia, it was possible to adjust the appropriate fuel/air mixture by trial and error without stalling it, although this varied between different types of engine, and in any case it required a good deal of practice to acquire the necessary "knack". After starting the engine with a known setting that allowed it to idle, the air valve was opened until maximum engine speed was obtained.

Throttling a running engine back to reduce revs was possible by closing off the fuel valve to the required position while re-adjusting the fuel/air mixture to suit. This process was also tricky, so that "throttling back", especially when landing, was often accomplished by intermittently cutting the ignition using the blip switch.

Cutting cylinders using ignition switches had the drawback of letting fuel continue to pass through the engine, oiling up the spark plugs and preventing the engine from restarting. Also, the raw oil-fuel mix could collect in the cowling. As this could cause a serious fire when the switch was released, it became common practice for part or all of the bottom of the basically circular cowling on most rotary engines to be cut away, or fitted with drainage slots.

By 1918 a Clerget handbook advised maintaining all necessary control by using the fuel and air controls, and starting and stopping the engine by turning the fuel on and off. The recommended landing procedure involved shutting off the fuel using the fuel lever, while leaving the blip switch on. The windmilling propeller made the engine continue to spin without delivering any power as the aircraft descended. It was important to leave the ignition on to allow the spark plugs to continue to spark and keep them from oiling up, so that the engine could (if all went well) be restarted simply by re-opening the fuel valve. Pilots were advised to not use an ignition cut out switch, as it would eventually damage the engine.

Pilots of surviving or reproduction aircraft fitted with rotary engines still find, however, that the blip switch is useful while landing, as it provides a more reliable, quicker way to initiate power if needed, rather than risk a sudden engine stall, or failure of a windmilling engine to restart at the worst possible moment.

Rotary engine - Wikipedia, the free encyclopediaFour stroke Agaricus. The lubrication is a total loss system (castor oil) as with a two stroke, which may be the source of confusion.

That sums it up nicely. It was essential to have power and the only way was with the 'blip' switch. It is worth noting that the Clerget had a life of only about 50 hours - but it depends on what was 'using' it.


On the Shuttelworth aircraft, as it was on approach, the blue smoke points directly to 'blipping' just as it should - but sadly the port wheel struck the top of a post as I saw it. The rest was almost inevitable due to weight and forward speed. The reason will be heard in due time.


As always, it is good to hear the pilot was OK.

of course the very low approach speeds of any WWI aircraft make a big difference when it all goes pear shaped - another 10 mph and he'd have turned right over - another 20 and it might have been a full on cartwheel

I never understood how many aviation pioneers walked repeatedly walked away from crashes until I realised the speeds they were flying at..........