Mobile, Launched.

Ship out with the new bracket, only narrowly escaping when I detect we'd a lock-on.

Dire Straits

The objective, to draw on allied support to assist the mightiest naval force in the world to sustain access to a waterway vital to their power and advancement of their broader war aims.

Terrain bordering the straits elevated and rugged, and thus decidedly difficult for an invading force to occupy and defend in the aftermath.

The opponent in these lower latitudes Islamic in religious preference and doggedly determined in the defence of their nationhood, to the point of wholesale sacrifice. 

The invaders led by a man sympathetic to the Russian's cause... stubborn, strong-willed, freely criticising those seemingly unable to see the superiority of his logic.

Yet eventually losing countless ships to mines, torpedoes and projectiles launched from foreign shores, besides devastating losses of infantry and naval personnel.

All eventually leading to his removal from office. 

Who, where and when?

Winston Churchill, Strait of Gallipoli, 1916.

Tuning Up

Sign off purchase of tins of tuna with which to sub for motors as we progress toward shakedown tests involving transport, besides PR shots for the website.

As a matter of fact these are almost indistinguishable from the real thing once they are sprayed up, and make for a tasty snack for your teams afterward.

Motors are mounted (from forward left, clockwise) to turn in directions CW, CCW, CW and CCW.

Or as per photograph: Soy & Ginger, Lemon & Thyme, Red Hot Chilli, Soy & Ginger.

Back to the Future #25

With the decision made on transportation viz. directly mounting at the rear of a 4x4 in preference to use of a flatbed trailer, a hard-mount is affixed to the underside of the cat in order to facilitate the operation. Note the addition of the struts previously posted, which serve to stiffen the rear end of the hydro-skis, which as you will recall are in this case made of lengths of extruded uPVC ordinarily used for skirting board.

Weighty Matters

Big day because I've to decide whether or not to give the go-ahead to the second prototype that is dedicated to hover. A while since we did this, but it's back on the scales for one of the four power-packs comprising ESC, motor and battery-pack. This comes in at a rounded .75 kilos, of which .35 belongs to the motor itself.

Meantimes the boat weighs in at a rounded 5.00 kilos, so we're looking at an all-up weight of around 8.00 kilos or about eighteen pounds... not bad for an eight-footer.

Turning to the tables provided by T-motor themselves ~ invariably optimistic ~ the section on the 280kV motor appears below. This is the slowest variant of the motor and it produces 280 r.p.m. per volt, whilst the alternatives provide over 400 r.p.m.

This requires the largest recommended prop turning slower, which is more efficient at the cost of needing more torque and overheating the motor... in the table every combo lists a working temperature except this one, which simply says 'HOT'.

Nonetheless we'll be burning these babies in a do-or-die effort to get this thing off the ground, even if it means throwing more volts into the ring. Indeed the figs here relate to 24V packs and we've only 22V, so there's capacity in hand to up the stakes with bigger battery-packs (whilst I'm loathe as ever to part with the cash).

Accordingly pick up your tables and we'll go through them together, if I could ask Gromit to assist please with the laser-pointer?

First off, my friends at Axis Aerospace recommend the motors run around 65% to provide room for differential thrust in hover. Nonetheless in ground-effect there's an element of stability anyway, as motors nearest the ground during any tilt provide the greater thrust and essentially correct the situation... I like to think.

As race-director on the day however I'll mandate use of 75%, for which the figure in the table is a mighty 3300 grams of thrust. Dividing by 24 and times 22 (as life is linear) we still clear 3025 grams. Thus with four motors we're looking at twelve kilos of lift for eight kilos of boat... in fact even at 60% we should have lift-off, Houston.

We're therefore cooking on gas and all eyes turn to me (both cats!) as I green-light the project, and the room erupts in whoops and hollers that I pre-recorded on the laptop for the occasion. The question for the next bored meeting (stet) is whether I ask my electrical engineering friend to wire the motors for a NASA-style static thrust test... or go straight to Axis and get them wired for flight as well as sound?

I like 'Plan A' as the entertainment value is through the roof, not least because of the pond there too where we could conduct static flotation tests. As doughnuts are finished off and the last of the coffee is drained, however, our moon-shot must turn its attention to how we get the cat from A to B in either case.

It ain't going to be easy, and if any one of you is feeling the need to drop out at this stage then see me afterwards and I'll knee you in the groin and wish you well.

Struttin' Our Stuff

Realise the second prototype (to be dedicated to hover) has uPVC skids that look too flexible altogether at the back-end, unlike their timber counterparts on #001.

They look to need stiffening with struts, and at first I was afraid ~ I was petrified ~ but now I hold my head up high recalling how the prototype Hawker Hurricane and Me-109 needed struts at the tail-end too!

To do this I've a couple of old fibreglass tubes which I've cut down to 350mm, and afterward squirted filler in either end to provide purchase for a pair of wood-screws.

One thing I've learned as I've got older is firstly always to use sun-screen, but also to avoid nuts and bolts wherever a simple screw will do.

The problem with droopy members is they'll sag in the hover, springing upward if submerged.

Nonetheless a search on that term at sharing site YouTube has put me in touch with a Dr. Nora Hayes, who says she can fix anything for just $300 per hour.

Great... and who knew an MD would be interested in maritime drones too!

If anyone is interested in an annual strut-meet where surviving Hurricanes and Me 109s are flown in for me to try out while owners get to sit in my drone, contact me. 

Proto Typing

Not all plain sailing, as I hoped to build a cat round this bod to hang in a small boat collection somewhere; but turns out the knockdown paint I bought for a pound a can is not all it seems. Far from the matt 'NATO Green' it appears on the tin, it does so as 'Kermit the Frog' gloss.

Clue was probably the tin featuring a ride-on lawnmower, of dubious use to NATO.* 

Nonetheless it was an excuse to consign it to the bin, not really liking its proportions and having altered them for each prototype.

It did impress tho' by resisting all efforts to dismantle it for disposal: centuries from now it will be unearthed by robots, one asking what it was and another replying some loser's flying boat?

As Basil Fawlty said, however... Well that's cost me, hasn't it?

* Currently the UK does provide these ride-on lawnmowers in support of its allies.