Welcome to the August update for the project of building our jet hydroplane Longbow as we work towards making a credible British attempt upon the Outright World Water Speed Record (WWSR) of 317.58mph set in 1978 by Australian Ken Warby MBE with his iconic fastest boat in the world, Spirit of Australia.
Way back in 2007 I was commissioned to do some architectural design work for a client by the name of Jerrod Hartley BEng, CEng, FRAeS, who commenced his career relatively local to me at BAE Systems. It was also during this period that I was involved with the restoration of Donald Campbell’s Bluebird jet hydroplane and in conversation with Jerrod at that time he kindly provided me with some information and advice regarding the properties of some of the materials that had been used to build that particular jet hydroplane.
After thirteen years at BAE Systems Jerrod undertook engineering design work abroad for other prestigious aircraft manufacturing companies including Boeing in the USA, Fokker in the Netherlands and then Airbus in Germany. He is now CEO of his own very successful company, Airframe Designs Ltd employing some very talented and knowledgeable engineers indeed, with the business located adjoining Blackpool Airport.
Airframe Designs coincidently works with two of Longbow’s local education partners, namely Blackpool & Fylde College and the University of Central Lancashire (UCLan) having engineering students / apprentices of the company at both of these sites.
Jerrod stumbled across a recent feature article in Powerboat & Rib magazine regarding Longbow and recognising myself as the author, he got back in touch with me for a catch up and asked if he could come and pop round to have a look at the boat in my cottage workshop. At that visit Jerrod brought along his Design Manager, Chris Fleet who has considerable knowledge of composites and Design Engineer James Hodgkiss all as shown in the photograph below at their introduction to Longbow.
The visit turned out to be far more than just a casual look at Longbow as all three went right through the entire build to date, asking a multitude of technical questions for which presumably I must have given them the right answers because as we closed the meeting Airframe Designs took the decision as a business to come on board to partner with the venture and it is accordingly a pleasure to now have their company logo displayed upon our workshop wall.
Coincidentally and rather helpfully Jerrod’s company, Airframe Designs have also previously worked with one of our latest sponsors of the Longbow project, that being Manufax Engineering, who had previously been an engineering partner with the land speed record attempt car Bloodhound.
Those of you who have been following our little venture will appreciate that our primary focus at present is Longbow’s driver cockpit. In this regard Airframe Designs are currently converting my 2D CAD drawings as specified by our Lead Design Engineer Paul Martin into a 3D CAD engineering model. This being required by our sponsor Accles & Pollock who previously manufactured the square section high tensile steel frame for Bluebird way back in 1954 but now for Longbow require all the more complex round section joints 3CAD modelling in order that these can be CNC laser cut along with tube bending prior to being TIG welded together.
In respect of Jerrod he is also a Compliance Verification Engineer (CVE) for aircraft, which if you are not familiar with the term, it relates to a senior engineer who provides independent final verification of an aircraft’s compliance with airworthiness requirements, acting as a ‘gatekeeper’ for certification, reviewing design documents, analysis and test data. The domain of a CVE is aircraft structures, systems and propulsion such that we trust you will appreciate the significance of having a fully qualified and experienced CVE associated with Longbow.
The fact that we already knew Jerrod, that his company work with two of our education partners and very helpfully their location is right on our doorstep backing on to Blackpool Airport could not be better.
Of note Blackpool Airport is where Steve Hartley of WEC who are a sponsor of Longbow has his L39 Albatros jet aircraft based there and last month the Airport allowed Steve to test his historic Formula 1 McLaren MP4/1 car there.
With Blackpool Airport being so close to us, having appropriate support there including fire and rescue crews on hand for the aircraft, being a secure safe location and our new partner Airframe Designs adjoining it, then you may appreciate how the Airport presents a suitable location for statically testing Longbow’s twin jet engines and systems. That being the case this month we had a very positive conversation with Helen Roberts who manages that side of things at the Airport regarding the logistics of what we will require for such testing at that location.
Our driver for Longbow, serving RAF pilot Flt Lt David-John Gibbs (DJ) hails from Southport with his family still based there and this month DJ had the pleasure of featuring at Southport’s tremendously popular annual Air Show. On this occasion DJ had been invited to perform an exciting aerobatic display at the Air Show piloting a BAC Jet Provost T.5A owned by Jeff Bell and Nick Snow with the aircraft usually based at East Midlands Airport.
This particular aircraft was originally built local to us at what was then BAC Warton (which then became BAE Systems, Warton) and was accepted by the RAF in 1970. Further detailed background to this particular historic jet aircraft and it’s fantastic restoration to flight at an eye watering cost of £240,000 is available upon the following link:
https://jetaerobatics.weebly.com/history-of-xw324.html
As the Southport Air Show is a two day event this Jet Provost along with some of the other display aircraft featuring at the event including a Fairey Swordfish biplane were flown into Blackpool Airport at Hangar 3 with that facility acting as a temporary base for them. Unfortunately due to high winds and rain some of the display aircraft such as the Battle of Britain Memorial Flight and a de Havailland Vampire Cold War era jet had to cancel their displays, so it was every credit to DJ’s flying abilities for undertaking aerobatics with the Jet Provost in such bad weather. The following link shows DJ piloting the aircraft at the event:
Victoria Thornely who is Operations Manager at Hangar 3 kindly granted me permission onto their area of the airfield apron in order to meet DJ and Nick for them to give me a brief tour of the Jet Provost whilst it was based there.
I found this of particular interest as the Jet Provost’s single Viper Mk. 202 jet engine which takes the aircraft to a top speed of 440mph is a lower powered version of the twin engines (Viper Mk. 535’s) we are using in Longbow. On the spur of the moment I decided to capture some video footage upon my phone of DJ talking me through the Jet Provost’s engine bay area and cockpit and having looked back at it later I thought it may be of interest to those of you following our little venture. As previously mentioned with the weather blowing a gale please excuse the wind noise during the recording but special thanks to my friend Howard Bryan for piecing the short video clips together as follows:
In other news this month we are pleased to report that our good friend Dave Warby and his Team had a very successful weekend of further testing of their jet hydroplane Spirit of Australia 2 at Blowering Dam, NSW Australia.
Dave has so generously given some degree of feedback as follows upon his latest round of testing, in addition to an insight of some of the challenges teams face when attempting this record in modern times, compared to when his late father Ken did so. These words from David are very wise indeed not only for the armchair critics but also for ourselves when we come to run Longbow:
“A mixed bag of weather hit us over the weekend. Saturday was cancelled due to high winds and rain throughout the Alpine regions, with snow falling at 600 metres, Sunday started much better in the morning, though winds increased over the day. We had some comms issues early on. SOA2 had a new rear ski development fitted over the past three months to improve rear-end stability above 250 mph.
Credit Pete Wilson
At our last test at 278 mph, we noticed slight drifting above 250 mph, which needed to be resolved. The new ski also changed how the boat sits on the water, requiring adjustments to our horizontal stabilizer to suit the new setup.
On our first run at 150 mph, porpoising was amplifying. After a wing adjustment, this settled down for our second run at 210 mph, though it was still noticeable. Another adjustment stabilized the rear of the boat at 270 mph on half the course (4 km, with whitecaps at the far end). The handling and rear of the boat now feels solid and planted—this issue needed to be resolved, and we feel it has been. We can now move forward in a safe, measured manner.
It was a pleasure to have Cheryl and Rosco McGlashan with us again—an amazing Aussie duo. We look forward to working with them in the near future, along with Lawrence Legend, a mate of Rosco’s and an incredible stuntman. We also made a few 150 to 170 passes close to the shore for the spectators who came to check out the runs, could see the boat up close as the as the 8 km record course is 1 km out from the shoreline.
As with any form of unlimited speed record-breaking in this day and age, the biggest hurdle is securing permissions and approvals from authorities to run a jet boat on a body of water. We get roughly three opportunities per year (about one and a half days each). Gone are the days from the 1930s to the 1970s when you could set up camp next to a lake for weeks to develop a boat for a world record, testing multiple times a year with insurance or running a test whenever you liked.
This is a challenge for any speed record challenger, on land or water, in 2025. The original Spirit of Australia throughout its running life in the 1970s averaged around 10 runs per year over four years, with access to waterways throughout Australia—very different times and legislation. Ken would go faster only when the boat was ready, not before. Yet, he was sadly criticized for this, even by some who should have known better.
We’d ideally need a week or two on the water, given the boat’s current state, to fine-tune and dial in the setup for speeds from 280 mph to 350 mph. This boat is designed for sustained high speed, not over 1000ft or a few seconds at speed. We wish it was, be very easy. Running when the weather is good would help mitigate risks as we book and get approvals for tests 10 weeks in advance. In the meantime, we’ll progress as it stands. Either way, we will move forward later this year—safely”
We wish Dave and his Team every success with their ongoing development of the craft and we count ourselves so very lucky indeed to have both Dave and his partner Lesa’s longstanding friendship and Dave’s invaluable ongoing technical assistance with Longbow.
Also this month at the Lake of Ozarks, Missouri in the USA saw owner driver Darryl Cutter and Steve Curtis drive the two seater offshore powerboat Darana Hybrid (formerly Spirit of Qatar) over a three quarter mile (1.2km) course at their annual special event there to a top speed of 242mph. The highest speed the craft has run previous to that was 244mph back in 2014 coincidentally on the same course under her original name of Spirit of Qatar. This amazing boat is powered by twin Lycoming T55 Chinook helicopter turboshaft engines developing 4,400shp each, driving twin propellers through respective gearboxes as shown in the link below:
https://www.youtube.com/watch?v=Gx2JNN-Su8k
A single one of these Lycoming T55 turboshaft engines is also used to power the American H1 Unlimited circuit racing hydroplanes that are likewise propeller driven through a gearbox. The fastest speeds of propeller driven craft have been from zero to 260-270mph in around 4 seconds by American drag boats over a very short sprint distance of a quarter of a mile or less.
One might ask why is it that a pure thrust jet boat holds the title of the current fastest boat in the world and no longer as was historically the case a water immersed propeller driven boat? Also why has a propeller driven boat not gone over 300mph over a timed distance of one kilometre or a mile?
The answer to those questions primarily revolves around (no pun intended) the tremendously fluctuating colossal forces acting upon the propeller that weighs around 9kg whose sole purpose is to push the boat along at these very high speeds. To the general public they may simply presume that all boats have their propellers constantly immersed deep within the water to push the boat along but for very high speed boats / hydroplanes that is not always the case. For these extremely fast boats the propeller is often only partially submerged in the water when the boat is running at speed under a phenomena known as ‘prop riding’ as shown in the following photo / sketch:
This ‘prop riding’ means that as the propeller blades rotate, which for these very fast boats is upwards of 170 revolutions per second, then with each individual revolution those propeller blades go from spinning relatively freely in the air to then slamming down into the essentially incompressible water where that liquid is around 800 times more dense than the air it was spinning within a microsecond before. The blades then rotate within that water to push the boat along before coming back out of the water into the freedom of the air.
The boat unlike a car has no suspension and is therefore bouncing along as it interacts with each ripple or wave of the water surface it travels over at very high speed and with all of this going on you can see how much you are asking of that propeller to remain intact where the water is like concrete at these very high speeds.
The upshot being your propeller can push you along very quick over a very short distance (i.e. drag boat) or it can push you along a bit slower over a much longer distance (i.e. Darana Hybrid) but the propeller is going to scream it’s had enough I am out of here’ if you try to do both by asking it to get you to 300mph or beyond irrespective of how massively powerful your engine is.
Here is a little clip of a H1 Unlimited Hydroplane running at a shade under 200mph saying hello to the laws of metallurgy physics and goodbye to its £13,000 propeller, of which you wouldn’t want to be anywhere near those sharp chunks of metal as it exploded in all directions including skywards:
https://www.youtube.com/watch?v=pnrQYLQoxok
So that folks is why you use pure thrust jet engines if you want to try and follow in the steps of the Warby family to go over 300mph in a boat. As we close this month’s update I hope that I have not bored you too much and if you have not already done so please follow our Longbow jet hydroplane page upon Facebook for updates as our project develops.