SPECIAL PROJECTS
PIPER CLUB
Jono Holland, Piper Cub J3
I’ve done lots more flying today and have decided the new prop is the dog’s b*****ks.
I have spent quite a bit of time analysing the power curve etc of my engine, and the rpm’s I am getting at static, unstick and climb are spot on, and are now really making the most of the HP the engine has. And it is so ssssmmmmooooooooottthhhh!!
I was happy with my Cub’s performance and wasn’t convinced it could be any better. After several hours of careful testing, I have calculated a 15% increase in climb performance and a 9% increase in cruise speed. Added to that, it is considerably smoother than the prop I have been using until now, as well as looking stunning.
The venerable Piper Cub is one of the best known and most successful aircraft of all times. Hercules Propellers produce propellers for range of variants, including J3, L4H and L18, fitted with different engines, A65, C85, C90, O-200 and O-235.
For each individual airframe and engine combination, we have developed a propeller to get the best possible performance from these aircraft. In fact our customers tell us that Cubs have never performed so well! These propeller designs have been fine-tuned to allow the most efficient RPM for each engine and the best compromise between climb and cruise performance.
Like all Hercules propellers, our Cub propellers can be finished in any colours you choose, including a scheme to resemble the original 1930’s American propellers.
BRISTOL SCOUT
David Bremner, Bristol Scout
The propeller for our Bristol Scout may be a perfect reproduction of the original, but it is unquestionably a work of art in its own right. Hercules propellers took endless pains to get it exactly right – even to the extent of finding (goodness knows where) the letter stamps that would reproduce the correct typeface for the markings on the propeller boss. We can’t wait to see how it performs in the air!
Francis Donald Holden Bremner flew the Bristol Scout during the First World War. His grandsons David and Rick Bremner, along with their friend Theo Wilford have been rebuilding his aeroplane from a few small parts kept as souvenirs – the control stick, rudder bar and one magneto.
The trio started building the replica Scout in 1983 – it is due to be flying in 2016 to commemorate the battle of the Somme.
Type C aircraft was first ordered by the British government on November 5, 1914, in a 12 aircraft production batch for the Royal Flying Corps. It was later commissioned by the competing Royal Naval Air Service (RNAS) in a 24-aircraft batch and its first combat was in February 1915. It was armed with a standardised mounting and a 7.7mm Lewis machine gun along the left side of the fuselage away from the spinning propeller arc. Some were also finished with their guns fielded across the upper wing assembly.
Targets ranged from enemy aircraft (patrol, escort, interception), bombers, observation balloons, ground-based ‘targets of opportunity’ and even Zeppelins, which regularly patrolled airspaces.
The Bristol Scout was a single-engine, single-seat fighter intended to supply ground commanders with an advantageous ‘eye in the sky’. The initial prototype, Scout A, was unveiled in 1913 with a top speed of 100 miles per hour, a service ceiling of 14,000 feet and an endurance of 2.5 hours. Its design was regarded as very streamlined and consisted of a well-contoured fuselage with the single rotary piston engine set to the front and a conventional tail to the rear.
The engine powered a two-bladed wooden propeller, of which a faithful reproduction has been produced here at Hercules from American Black Walnut.
The open air cockpit was held just under and aft of the upper wing assembly with generally adequate views. The Scout B was established as an early militarised form and led to the development of the Scout C – which was the one flown by the Bremner’s grandfather.
STAAKEN FLITZER
HART-ATTACK CASSUTT RACER
PITTS SPECIAL S1-S
TIGER MOTH
Mike Clark, Staaken Flitzer
I have managed to get some more flying in the Flitzer this morning and can report my findings. The aircraft seems to get off the ground quicker with your prop and initial climb is good. I flew level with full throttle and there is an increase in cruise of 4 mph to 91 mph. This gives 3000 rpm on the gauge which corrects to 3300 actual. I did aVNE dive with no problems. The prop is much smoother in flight than the previous prop.
This afternoon was one of those special occasions when the weather gods came up trumps. I should have worn warmer clothes but that didn’t detract from the half hour of magic in the air. I counted 16 hot air balloons also enjoying the experience.
Hercules prop is performing very well with a 5 mph increase in top speed, a shorter take off roll and a much smoother running engine. In fact it felt like I was in the 17th balloon it was so smooth!
Lauren Richardson, Pitts Special S1S
Hercules have done an absolutely fantastic job of fine-tuning my propeller design to give a very precise level of performance for what is a very demanding style of high level aerobatics for both Advanced competition flying and fast, dynamic airshow performances.
I wanted to gain cruise speed for transit flights without losing too much climb performance – my Hercules propeller has vastly surpassed my expectations, not only in improved cruise (my Pitts will now happily achieve 165mph straight and level, cruising at a comfortable 150mph), but in reducing engine revving during aerobatics without any real world loss of performance. It’s also less noisy than my old propeller, meaning the neighbours are much happier whilst I practice!
A fantastic product, beautiful finish and amazing design service.
Des Hart, Cassutt Racer F1 Silver Class Winner
Hercules Propellers played a huge part in our win by designing and manufacturing our custom race propeller which was not only absolutely stunning visually but delivered the goods in the race.
Hercules started the design process with a clean sheet of paper and our input as to desired race revs and estimated speed we hoped to achieve.
The guys were bang on the money and we saw an increase in 15mph when we switched to the race prop which allowed us to turn more revs and develop more power. Looking at the final race speeds its clear that without our Hercules Propeller we would have placed well down the pack.
Wim Stapel, Tiger Moth
Propeller arrived perfect and the day after arrival was put on our Tiger. Starting up was already a great difference as the engine run real smooth with the new propeller. The noise seemed to be also less. After test running it and flying it for an hour we re-torqued it and made another 5 hours (now with the perfect stable weather) and it is a joy to fly.
Performance and smoothness of operation is great and we are real happy with it.
Following frequent requests from Tiger Moth owners, engineers and restorers, for a prop that not only performs well but also looks like the original propellers fitted by De Havilland, we accepted the challenge to design and produce such a prop.
For the hub, we copied the exact shape of the De Havilland made DH 5220 original fitment, but with a 72 mm centre bore, so it will fit either taper or spline type Gipsy Major prop drives.
To the bystander, the blades closely resemble the symmetrical plan form of the originals, blending into the hub with the correct curves, looking just right with our elliptical tips.
Although the propeller looks like the originals, needless to say, we employed our sophisticated computer programs to fine-tune all of the parameters that go together to make an aerodynamically optimised propeller.
Des Hart’s Cassutt Racer, ‘Hart-Attack’ flew at the reintroduction of Formula 1 Air Racing at Lleida, Spain, in 2014.
Over the clear northern Catalan skies, 11 internationally renowned pilots battled it out at Europe’s first-ever international Formula 1 class air racing series – Air Race 1 – in Lleida, near Barcelona, Spain. Pilots from the USA, UK, France and Sweden revved up to showcase some of the world’s best air racing. Des and ‘Hart-Attack’ stormed to a win in the Silver class race, his Hercules custom racing propeller giving him the edge he needed for a decisive victory.
Des states: “The guys were bang on the money and we saw an increase in 15mph when we switched to the race prop which allowed us to turn more revs and develop more power. Looking at the final race speeds its clear that without our Hercules Propeller we would have placed well down the pack.”
Lauren Richardson is an experienced aerobatic pilot, with very demanding requirements for her aircraft. She came to Hercules back in 2013, asking us if we could produce a propeller that would be less noisy than her existing one, produce a slightly better cruise speed and not lose any ‘aerobatic’ performance.
The aircraft is a modified Pitts Special S1-S, powered by a stock Lycoming IO-360 engine (producing a theoretical 180hp).
Working with Lauren to determine what ‘aerobatic performance’ really means for us as propeller designers, led to a design that had several rounds of test flying and some subtle adjustment, before the final incarnation was settled upon.
During 2014 Lauren flew our propeller all across the UK at numerous events and airshows and has been extremely happy overall, with both the performance and the exceptionally beautiful finish of her bespoke propeller.
As an idea of the performance she is now getting, she claims a rate of climb in the region of 2,200 feet/minute, a max. cruise speed of 165mph – quite impressive for a draggy little biplane!
Looking good is not enough on its own. The propeller has to perform, so we called on Henry Labouchere – life long DH Moth pilot, engineer, restorer and raconteur – who better to asses the performance of our design?
Following thorough performance test flights, Henry declared:
“It is at least equal, if not better in performance to the best Tiger Moth prop I have ever flown and noticeably smoother than any”
Quite an accolade. Anyone who has flown with a Hercules Propeller will tell you how smooth they run and this can only be good for your engine and airframe condition.
Testing with a very standard, low compression engine Tiger Moth, Henry recorded a cruise speed of 78-80 kts at 1900-1950 RPM and achieving very good take off performance and an initial rate of climb close to 700’/min with two people on board.
So there we have it, a propeller designed specifically for the Tiger Moth, which looks like it is straight out of the 1930’s yet optimises the aircraft’s performance throughout the flight envelope.
The Staaken Flitzer is a modern day classic. Designed in the late 1980’s, this VW powered sports plane looks every bit as 1920’s as the designer, Lynn Williams, intended it to be. The previous propeller allowed the engine to over rev by a good amount, meaning that cruise speeds were poor and fuel consumption was higher than it should be.
Hercules designed a new propeller to reduce the maximum achievable RPM from 3400 to just 3000, this way making the most of the engine torque and allowing a larger diameter propeller which is more efficient. The result is that the maximum cruise speed increased slightly, no loss of rate of climb and fuel burn in economy cruise reduced from 17 litres per hour to 14 litres per hour.
In keeping with the style of the aircraft, the aesthetics of the propeller was as much of a focus as the flight performance. The ‘barrel’ sided hub is hand stamped and features a recessed, engraved aluminium front plate. The outer blades are painted a custom grey.
Being a bespoke manufacture, we can finish our propellers in a colour of your choice, and in either a satin finish like the one pictured on this page or full gloss as seen elsewhere on this site. Of course we can also finish a Tiger Moth propeller in clear varnish with a hand stamped hub, displaying the beauty of the wood. Alternatively, a combination of both looks very period, a clear varnished hub with painted blades.
All Hercules propellers are fitted with ‘Hercuthane’ bullet proof leading edges. By far the most durable leading edge protection from stones and rain.
EVTOL Rotor
