The Hovershow!

added by Emma on April 23, 2012 at 06:49

This weekend don't miss it! We'll be there with a snapper and a Marlin II Extreme. There will also be one of our customers with their craft buzzing around!

'Rampage' The final figures are in for the UK's most exciting small hovercraft engine!

added by Emma on April 12, 2012 at 10:08

So it was back into the workshops at OO Racing today to finalise the setup of our tuned Briggs & Stratton ‘Rampage’ engine.

You’ll have seen the results from the standard and ‘Savage’ engines from last week but of course, we were excited to test the most powerful engine in our range. With timing set and carburetors balanced…it was time to run it on the calibrated dynamometer.

Our goal is clearly to tune our engines for the maximum torque, rather than the ‘headline grabbing’ bhp figure. Torque is the true measure of the ‘turning force’ of an engine which is absolutely crucial in a hovercraft engine.  This is because hovercraft do not use a gearbox - instead they have a simple transmission and a fan which provides a fixed load. With a ‘peaky’ or high revving engine such as a two-stroke, response can be poor as you cannot select a lower gear to multiply the available torque like you can with a motorbike or car engine.  So, the goal of a hovercraft engine is low revs (economy/noise) and a flat torque curve for good response and easy cruising at speed.   

Below is the power graph showing both the horsepower and torque output of the Rampage engine -  compared with the standard Briggs & Stratton 35bhp Vanguard engine. 

  • Maximum Torque 70lb/ft at 3000rpm
  • Maximum BHP  55bhp at 4700rpm.

Now, because we run these engines to a maximum of 4000rpm, the engine can more accurately rated at 50bhp, which is what it produces at that figure. It’s quite possible to run the engine up to 4700rpm for maximum power, but this means further modifications to ensure no loss of the incredible reliability of these Briggs & Stratton engines.  

However, looking at the torque curve more carefully tells the real figure. The Rampage has a peak torque figure 15lb/ft higher than the standard engine… but offers over 80% of this figure from 2100rpm right through to 4000rpm.

You can see the huge difference from the other curves which compare the two engines.

So, 70lb/ft throughout a substantial part of the rev range is figure of interest to the hovercraft builder! Having tested this engine in one of our hovercraft at some length, the throttle response, performance and ability to cruise easily when well loaded is exceptional.

Just remember – no other personal / small hovercraft manufacturer that we know of has actually produced their own, ‘real-world’ power and torque figures for their engines by putting them on a dynamometer.

It should also be stressed that we've extensively tested the Rampage engine, installing it into real hovercraft and using it in a real environment. We don't exceed the safe usable rev limit that we've used for six years, and everything that needed to be done to ensure reliability... has been done!

So what now?

We’re currently working on making the engine available as a kit of parts for hovercraft builders to install themselves. If you’re looking to buy a personal hovercraft, then this engine is going to be of big interest! We’ve developed this engine (in association with OO Racing) for our new Coastal Pro Hovercraft but are making it an ‘off the shelf’ bespoke hovercraft engine for folks who wish to build a hovercraft, or re-engine their older two-stroke hovercraft. The aim is to have it available by the end of May 2012 – so please drop us a line to register your interest and we’ll keep you posted with pricing and delivery times.  

Rampage Engine

  • Layout - V-Twin
  • Cubic Capacity - 993cc
  • Bore -86mm
  • Stroke - 87mm
  • Max BHP - 50bhp @ 4000rpm
  • Max Torque - 70lb/ft @ 2800rpm
  • Carburettion -Twin Mikuni
  • Ignition - Bespoke CDi system
  • Engine weight - 56kgs
  • Cooling - Forced air cooling, no radiator/water system necessary.
  • Rotation - Clockwise when viewed from PTO side.
  • Starting - Electric, pre-engaged starter motor.
  • Cylinder Block - Aluminum Alloy with Dura-Bore Cast Iron Sleeve
  • Crankshaft - Ductile Iron 

The team at Flying Fish Hovercraft would like to thanks to Adrian at OO Racing – a genuinely lovely feller with an astonishing knowledge of small four-stroke engines. www.ooracing.com

 

BRIGGS & STRATTON 'STOCK' ENGINE VERSUS 'RAMPAGE' TORQUE CURVE

 

RAMPAGE POWER & TORQUE CURVES

 

BRIGGS & STRATTON 'STOCK' VANGUARD ENGINE VERSUS RAMPAGE - BHP

So, what is the plural of hovercraft???

added by Emma on April 6, 2012 at 13:55

Hovercraft or Hovercrafts?

Now, thats an often discussed subject and in fact we see it written see hovercraft, hovercrafts, hover craft and hover crafts! some overseas buyers even spell it 'Hoovercraft' but the only correct spelling is 'hovercraft' - whether its singular or plural. You may be talking about one small hovercraft or 10 large hovercraft but the word follows the same rule as the word 'aircraft.' in other words, you may have one aircraft or twelve aircraft, but you never have any aircrafts, air craft or air crafts!

Engine testing - Briggs & Stratton hovercraft engines on the dynamometer!

added by Emma on April 5, 2012 at 13:14

Few subjects attract more outrageous claims by unscrupulous sellers than…engine tuning and hovercraft! As a company that supplies hovercraft and also modifies stock engines, we felt it was about time we put up or shut up! So, Wednesday saw three of our engines bolted onto the dynamometer at Double O Racing www.ooracing.com to test once and for all the power being produced by both the standard and modified Briggs & Stratton engines we use in the Flying Fish range of personal hovercraft.

Adrian at Double O Racing is a top guy, fantastically helpful and knowledgeable. His dyno is fully calibrated, so it was a fantastic opportunity for us to ascertain, once and for all, the true figures that our engines produce.

The three engine specifications we tested were as follows.

Standard, completely unmodified Vanguard 35bhp engine, brand new –  The ‘Boggo!’

‘Savage’ specification 35bhp Vanguard. Brand new with light modifications to increase torque and drivability.

‘Rampage’ specification 35bhp Vanguard (twin carbs, CDi system and internal modifications)

After some modifications to the dynamometer drive to allow our engines to be safely installed, we fitted the Boggo engine. Commercial engines (Kohler, Briggs & Stratton, Honda etc) have a ‘governor’ fitted to prevent over-revving, something we can remove for hovercraft usage. This is because the hovercraft fan load is fixed and prevents the engine from exceeding its maximum revs….and unlike one or two of our competitors, we do not run past the design limit of 3800 to gain more power.  In the case of the Boggo, other than the marinisation required to make it run in a marine environment, removing the governor is the only modification made.

So, first power run and the 35bhp Briggs & Stratton  produced 35.4bhp! Remember this is a brand new engine – and we always get more power once they’ve got 15-20 hours on them.  This was excellent news and a great base to work from.

So, to the Savage Engine. This engine is modified slightly with the aim of improving throttle response, torque and power.  It still runs at a maximum of 3800rpm, just like the standard engine. Test results…37.1bhp, so up a little of 1.5bhp. Now, that doesn’t sound a lot, but the torque figure was incredible, increasing from 55lb/ft to 65lb/ft! A 10lb increase is a great result, and the reason why, when coupled to a different fan specification, the Savage craft is faster, more responsive and cruises at tiny throttle settings for 25mpg economy! We were genuinely delighted with this test.

Well, so far so good and it was time to bolt on the Rampage. This engine has been developed over the last twelve months and features twin carburetors, a bespoke CDi system and some internal work (sorry to be vague but we don’t want to give it all away!) But then we hit a snag – following some recent development work on it, we’d overlooked setting up the timing accurately and it was only ‘guesstimated’ – Doh! Adrian advised against running it too hard/too long without correct setting and we were running out of time for the day. So, we decided to do one quick run and see what we’d got, then knock it on the head until after Easter, when we’d have the time to set it up correctly.

 

I’m not going to tell you what we got from our test…but were very happy…..and still are but we also know that there’s lots more to come. Check out previous video of Adrians reaction as he sees the screen display after the run we’ll give full results and power graphs next week! VIDEO

The attached photo shows the screen display of the Savage and Boggo runs – the Rampage ones have been veiled for now!

Because we use new engines we can be sure that the engine you get in your Flying Fish recreational/personal hovercraft matches the results that you see here. Many hovercraft manufacturers use two stroke engines that rarely produce what they claim – and some even use ‘reconditioned’ (ie second hand!) car engines from Subaru or BMW.   In those cases, you could be getting as little as 75% of the claimed figures! So we’re chuffed with the results so far…and can’t wait til Easters over and we can get back into the workshop!

Happy Easter!

 

A Spring Bargain!

added by Emma on April 3, 2012 at 07:02

Flying Fish Hovercraft are delighted to offer this 2006/2007 Marlin II hovercraft - used craft don't come up for sale all that often!

This 2006/7 craft is in good overall condition. Good working order, goes really well. It's got a fantastic provenenace with just two owners. In October 2011, it was one of the two Marlin's that completed the Channel Crossing from Dover to Cape Blanc Nez http://www.thisiskent.co.uk/Hovercraft-heroes-finally-make-charity-voyage/story-13621879-detail/story.html

Powered by a 35bhp Briggs & Stratton, its fast, economical (25mpg!) and quiet.  Comes with padded seating, back seat, bilge pump, yellow beacon, storage compartments (plus under seat storage) skirt in good condition, all refettled ready for sale. SSR Registered.

The craft comes with a three month warranty direct from the manufacturer. In the unlikely event of any problems, just bring it back and we'll repair it.
No trailer included, but a new easy load one-man trailer can be supplied for £650.00

If you wish to come along and see the craft, please call us on (01304) 619820 - we're in Sandwich, Kent. You can call or email any questions to russ( att) flyingfishhovercraft.co.uk

More details can be found here


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