Todays Boating

[Ray Wood 3Participant @raywood3]

Hi Ashley,

The fan being able to breath is the key to maximum thrust, so the biggest inlet possible, must df aeroplanes have cheat holes underneath, not so practical on a boat 😀 you need a clear jet pipe with slight taper, acetate rolled into a tube is the lightest used at the moment with magic tape on the join, with the tube fitting directly on the back of the fan shroud with a hot glue gun.Regards

Tony Nijhuis on the rcm&e forum designs great models many DF's worth a look, I'm building his JP slowly.

Bluebird didn't look very aerodynamic to me, not much going to stop a jet engine going fast !!

Regards Ray

[ashley needhamParticipant @ashleyneedham69188]

It has JUST occurred to me that I can actually move the fan quite easily, as there is a rib either side it mounts on, so if I use parallel rails with notches (to clear the inlet lip) I can simply move it up and down, whilst lengthening the jet pipe of course. I think three positions would prove the concept…front, middle and rear, although not that far forward or rear wards.

it can’t go tooo far forward, as I plan to slot the battery in just after the air intake (as the whole rear section roof will lift off). Unfortunately the tailpipe will be in the way of really good access, and I spent an hour today mulling over the best location for the rudder servo. Probably I will make most of the boat hull, get the motor and see what it looks like with bits perched in place. I have a very fluid build practice and tend to problem solve as I go along once of course I have the viability of the project fixed in my head.

A 50mm edf with the same 4500kv motor is on eBay quoted at 650g thrust on 3s. This has more blades than mine,however mine is a 64mm unit. Hopefully I will be on at least a 1:1 thrust/weight ratio with the boat when finished??.

Ford Fjord blue seems to be the colour of choice according to my research, unless someone knows better!

Ashley

Edited By ashley needham on 07/01/2020 16:37:02

[Dave MilbournParticipant @davemilbourn48782]

I have a very fluid build practice

I have one of those, too….

DM

[ashley needhamParticipant @ashleyneedham69188]

3 litres!

Ashley (impressed)

[Dave MilbournParticipant @davemilbourn48782]

It's sadly just a stock photo from the Internet, Ashley. That bottle currently retails at nearly £80 and I'd never manage to smuggle it past Liz!

DM

Edited By Dave Milbourn on 08/01/2020 10:32:09

[Ray Wood 3Participant @raywood3]

Hello Guy's

That's not half as bad as being on day 8 of Dry January !!

Regards Ray

[Dave MilbournParticipant @davemilbourn48782]

My heart bleeds for you, Ray.

As long as you're not having to avoid consuming any animal products at the same time.

O, look! It's past noon…..

DM

[Richard BarnettParticipant @richardbarnett67129]

I went sailing this morning, so there’s my dry January down the toilet!

Ricky ye pirate 🏴‍☠️ 😂

[ashley needhamParticipant @ashleyneedham69188]

I am larfing too much to work in the shed.

Nothing better than burnt animal products and part of your 5-a-day (grain).

Have sketched out K7 plan and looking quite good. Spending a fair amount of time staring at the plan and trying to envisage the build sequence, however need that fan unit.

As usual, trying to keep a reasonably authentic shape means imposing restrictions on where “stuff” can go. For instance the fan can’t be too far forward or I can’t get the battery in, bearing in mind there will be a big tube behind the motor to take the air out smoothly. It means there will be about 5 or 6 inches of inlet duct before the motor.

Also as usual, for such a voluminous hull, the space is remarkably restricted.

Interesting vid on youtube demonstrating the difference in noise between a 5 or 12 bladed fan in a similar sized edf.

The 5 blade one has much more whine than the 12 blade one. What you want really. A K7 has to sound jet powered eh? (Mine has 5 blades, or at least, hopefully will have.

Ashley

[Trevor HollowayParticipant @trevorholloway99134]

Have fitted out the EDF dragonfly, all working well on the bench.

Hopefully not too windy on Sunday for the first test run.

So far Ginuary is going Ok for me !

[Richard BarnettParticipant @richardbarnett67129]

Hi all,

the templar ship is now on You Tube for your perusal under ‘Templar ship at Bushy park’.

been an interesting build, the hull went very well but the first mainsail I made was too small so it was out of proportion to the rear so I had to make another and lengthen the yard. The winch control cable tubes have been moved three times and the keel weight has been moved and re cast twice, not forgetting the rudder which has been enlarged twice and been given more throw!

At one point it nearly ended up as a nice windowsill ornament! Anyway, please have a look it’s only a short video and you might be inspired?

Ricky ye pirate 🏴‍☠️

[ashley needhamParticipant @ashleyneedham69188]

It’s horrid and grey and windy here.

Attempted to make the bottom of the K7 in balsa but failing miserably. Difficult to accurately mark, cuts veering off, and I know that serious remedial work will be needed for a smooth underneath surface. SO. Nipping to Addlestone models for some 3mm liteply and hoping the internal stiffeners will be sufficient to rigidise the structure.

Hoping fan will arrive today. Having difficulty envisaging in 3D the relationship vis battery insertion, edf location as forward as poss and maximising inlet area. Not sure which is worse..along inlet tract or a long jet pipe? I may make a card model to sort these issues out. Testing might mean a half finished boat and double sided tape covers.

Tomorrow might see the Invincible if it’s windy, or even the Herald!

Ashley

[harry smith 1Participant @harrysmith1]

Hi Men

Our first club run of the new year in the canal.

**LINK**

No, I was not driving the Spearfish !!!!!!

I was just running my Hellen Fishing boat.

May all your boating this year be good ones.

Regards

Harry Smith

[Richard BarnettParticipant @richardbarnett67129]

I present my latest offering a fast electric trimaran called the devils sausage stabber! Give you a race Noel when it’s finished?

Ricky ye racing pirate 🏴‍☠️

[NoelParticipant @noel26080]

Ho ho. Looks a lot more stable than my tooth pick already! Are they right angles at the keel or a bit broader? What will the engine be?

I was just thinking how relaxing it was the other week when there were about 4 sailing boats out.

[ashley needhamParticipant @ashleyneedham69188]

Firstly. Yesterdays boating. After a blustery and wet start, weather turned out nice.

ZiS and medium lander going well in the bluster.

Highlight was Trevor's ducted fan Dragonfly. It set off really well and got on the plane on its unfeasibly small foils easily and not using all the awesome power of the fan. HOWEVER, wildlife got in the way, necessitating a slowdown, and the hull was seen to dip momentarily underwater. I think that likely the hatch may have peen pushed off then, and quantities of moveable ballast were ingested…as despite turning round to face us, the craft was very lo in the water and moments later, fortunately a bit nearer, it was lower still., Some would say….

Boat was salvaged by a pirate and 10m pole. No damage fortunately. Good test, went well and showed good promise. Some attention needed to waterproofing is all.

Three Christmas present boats made very short appearances. Not as much fun as it used to be, as most of them are on 2.4G now and unjammable…

Look forward to seeing how the sausage trio works.

Ashley

[Richard BarnettParticipant @richardbarnett67129]

Noel, in answer to your inquiry the main hull has a small flat bottom as the cheapo 3ply wouldn’t bend where I wanted even after a good soaking and the motor is an old 540 super dooper ex buggy job I’ve had for about 25 years along with the flexible prop shaft. Sorry I’m a bit old school but it should go well if I can get it on the plane.

This is a side project while I was getting the hump with my Templar ship when it wouldn’t sail properly, as you know sometimes you have to step away before you set light to a project! 😂

Ricky ye pirate 🏴‍☠️ (fast 540 and no idea!)

[ashley needhamParticipant @ashleyneedham69188]

Richard, we will look forward to seeing your flat bottom soon.

Disaster on the Bluebird EDF front. Instead of sending a 64mm 5 blade fan unit with 4500Kv motor the inscrutable Chinaman has sent a pair of edf ducts and 12 blade fan units (with couplings). This is no good! The new ducts are moulded for a motor about 21/22mm in diameter…some of them seem to show an odd brushless out-runner motor with a long flanged end, and so are useless even for playing with as almost nothing will fit unless you get the right motor.

Why don’t I keep the fans and get the correct motors?? It is an issue of current draw. More fans means more load, and 4s is the battery specified for the whatever motor should be on these units, and mentions of 35/40 amps gets bandied about! My 4500 motor is for 3s.

i will have a spare 20mm motor but the shaft is 2mm and the 12 blade fan adaptor looks to be 3mm or 3.17.

Other than that the build is coming on. Too easy really…the fuselage is almost done, the sponsons need some artful sanding, the sponson support 4mm carbon fibre rods are in. Barring waiting for the motor the next and tricky bit will be making the fuselage top. This is projected to be made from 0.8mm ply, two pieces and will be removable for access but I have no idea how to either mould it to keep the curve or attach it to the main body. Ply hoops would be the way but I want as clear an inlet as possible, and at the moment the motor will be in the middle of the cockpit-tail bit, limiting where hoops can go. I could use sheet styrene for the top, and spring it in place….hmmmm.

Ashley

 

Edited By ashley needham on 15/01/2020 08:53:34

[Ray Wood 3Participant @raywood3]

Hi Ashley,

Have a look at the 4Max website, George now stocks the up to date EDF's with the matching motors, and he has them in this country, he is a very helpful guy to talk too as well

Regards Ray

[ashley needhamParticipant @ashleyneedham69188]

Hi Ray. Just had a look….good stuff there. Like the look of the 4s 64mm edf but running on 3s (drops current from 39A for dedicated 3s version to 23A. but retains a monster 640G of thrust!!

I am aiming for less than 300g of hull, 200g batt, 150g edf and then a few here and there for esc…..perhaps less than 700g total, hopefully 650 as a target. The 3s dedicated puts out 850g if I was to want more, but at quite a hefty decrease in running time?

Ashley

[NoelParticipant @noel26080]

Are you really targeting a thrust:weight ratio above 1?

Going to be quite peppy if so. My edf speedboat goes ok but I don't believe it could accelerate itself vertically!

[Richard BarnettParticipant @richardbarnett67129]

Ooooh VTOL Ashley, I’d like to see that!

Ricky ye pirate 🏴‍☠️

[ashley needhamParticipant @ashleyneedham69188]

1:1 frust  ratio…yes. The worse case scenario is shoving off from the side and just not getting up on the plane.

K7 is not a very streamlined thing, and has a miserable underwater shape as normally seen viz. streamlining. This didn’t matter too much with a massive jet engine, but the flat plate of the hull needs a decent bit of push to release it from the water.

Besides which don’t forget the Bushy motto,….”there is no such thing as too much power”

If the fan situation isn’t sorted soon I might try the bare hull with one of my brushed edf units to see wits wot.

Ashley

Edited By ashley needham on 16/01/2020 18:51:28

[Trevor HollowayParticipant @trevorholloway99134]

Just received a pair of 50mm 12 blade 4000kv fans, you can give one a bench test if you want.

[ashley needhamParticipant @ashleyneedham69188]

Cheers Trev. Will see how we go.

4000Kv fans…. for Buzz?

Ashley

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