[Rachael Posts: 8 Status: Offline]

Hi,


I’m living in Cornwall now but would be keen to attend any crusie in the Bristol area!


Loads of cruises going on up North and in the South East but would be really keen for one closer to home!


Thanks in advance 
Rachael Gifford

[rossfloyd Posts: 2025 Status: Offline]

That's innovation !

[Warby Posts: 1043 Status: Offline]

Quote

   " I would also think you might want to beef up the engine mountings and use box section steel.  If the engine moves and the fan impacts the cowl you will have a catastrophic failure and won't be going anywhere until fixed,  which is a nightmare job away from home. I have several T shirts for that one "

Regarding blades catching cowl, many years ago (about 40!!) I built a Scrad HC out of wood, the "lift cowl" was rigidly secured to the flexibly mounted ( with exhaust bobbins) engine frame. There was about 1.5 inch clearance between the cowl where it went through the deck, the flange of the cowl was sealed with foam to the deck. If I hit an obstacle the whole frame could move slightly without the blades catching!! It seemed to work ok and I could have minimum blade/cowl clearance!

[rossfloyd Posts: 2025 Status: Offline]

Regarding cowlings, Britannia had the early BBV slotted cowl that was pulling a vacuum with the 13 bhp lift engine, so I cut them out and put a pair of large spray deflector intakes. It was quite a complicated GRP job with lots of compound curves ( hot melt glue and foam core works wonders ! ).  It gave a huge improvement as the intake for lift air is unrestricted.

[rossfloyd Posts: 2025 Status: Offline]

Grass is a real issue for small craft as is vegetation for larger ones !  Due to the low ground pressure, the skirt can't compress the grass and thus there is an air gap under the skirt ..and all your cushion air is lost. 


I would also think you might want to beef up the engine mountings and use box section steel.  If the engine moves and the fan impacts the cowl you will have a catastrophic failure and won't be going anywhere until fixed,  which is a nightmare job away from home. I have several T shirts for that one :-(


Engine sizes also depend where you are going to operate - at Weston you need a lot of spare lift due to surface conditions - if river cruising you may get away with less.  I increased Britannia's lift from 8 to 13 bhp and it transformed the craft.  Not particularly in the way of handling,  but for obstacle crossing, mud gullies and more relaxed operation.

[nealwreford Posts: 28 Status: Offline]

No worries Ross, hope your feeling better.

[rossfloyd Posts: 2025 Status: Offline]

Sorry for lack of response . ....had flu :-(

[Ian Brooks Posts: 3552 Status: Offline]

Hi Ian, can you lift under the hull with straps - they could be stopped from slipping by looping them through the handling handles?

Hi

You need to be able to fit and remove them whilst floating in the river. They can't be left in place because the next time you see them they'll be in the fan  It happened already! Fortunately the fan chopped them up and all was well but it was a near miss. Usually fitting lifting points just takes a bit of thought but isn't too hard, each one is probably only taking 150kg or less on a craft your size. 

Ian

[nealwreford Posts: 28 Status: Offline]

Hi Ian, can you lift under the hull with straps - they could be stopped from slipping by looping them through the handling handles?

[Ian Brooks Posts: 3552 Status: Offline]

That's a 12 cubic inch lift engine, probably 6 - 8 hp.

I think they are 5 hp. IIRC, they had a 30 HP thrust, making them useable in the F35 of the day.

The 5HP lift will be challenging - thats the reason why it struggles in the long grass, there's no lift margin at all. This was a compromise to get the craft into the F35 formula, a cruiser of similar size would normally have a 10-12hp lift engine to provide margin - racing is on very short clipped grass only. Happily, it wont be too big a task to change it, although you should watch weight distribution, might need to move something backwards to counteract additional weight of a larger engine. But - it was clearly useable before, so I would put it to use and then think about any changes.

Regarding the handles - you'll need to be sure (best to test it) if anything breaks whilst on the crane it'll fall 20 feet and then get swept away! They'll probably need beefing up underneath as they arn't normally designed as lifting points. A big alumium plate underneath will probably do it. It needs to lift with the bow 1-2 ft higher than the stern.

Drop me an IM when you are ready to come over.

Ian

[Philip Posts: 2436 Status: Offline 12" above the Earth's surface WWW]

That's a 12 cubic inch lift engine, probably 6 - 8 hp.

[nealwreford Posts: 28 Status: Offline]

Hi Ian, that would be great thank you - when you say lifting points - it has four handles on the side (rope) is that good enough?
Cheers
Neal

[nealwreford Posts: 28 Status: Offline]

Lift engine p/n

[nealwreford Posts: 28 Status: Offline]

Lift engine fitted

[Ian Brooks Posts: 3552 Status: Offline]

I notice that it seems to be working ok on mud and water in the video - do you think that will be the case for mine?

Probably is one of the ones in the video. Given that they were working ok back in 2008 it should be ok, although the bonnet will be a significant restriction on lift air flow. If you fancied bringing it over to Gloucester I'll be happy to take a look at it with you. It would need lifting points for the crane if we were going to drop it in the river though, but we can definitely check the lift system out.