Vought V173

Seeing the fingers in the shot certainly helped show the scale.

At last the 10x5 3 blade CW & CCW props have arrived. To mark the occasion I printed a new test nacelle but in LW-PLA and adjusted the spinner so it fitted the 3 blade prop.
 
Not tested it yet but if it runs OK I will have to start designing and building the airframe.
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The way my CAD package works rectangular holes it has to be. LW-PLA is so soft touching the props is not a concern.
The motor is cooled by air flowing over the surface of the bell!   
With a predicted thrust to weight ratio about 2:1 I doubt it will ever use full power for more than a couple of seconds.
The ESCs will be close to the battery in the body of the plane and have the benefit of the scale leading edge intakes and air outlets.
I am not expecting there will be any long flights! 
 

I have now run the motor with the 10x5 three blade. A bit alarming just holding a 28mm diameter hollow LW-PLA tube!
On 2s full power 9A & 50W
On 3s full power 18A & 200W
Given the motor rating is 170W for 60sec max it is a bit over propped on 3s.I doubt the V173 will weigh more than a pound so even on 2s its100W/lb & on 3s just ridiculous. 
I will look into adding motor cooling vents and possibly a "built in" exhaust fan.      

Interesting scale in that photo between the radius of the prop and motor.  Good fun watching this beastie evolve...

And wondering about heat rejection - yes the motor casing is exposed but the windings are in a closed space and not all that far from LWPLA which does tend to go soft if it goes much over 60C. Easy to check - temporary mount, run it at 1/3 to 1/2 throttle for 10-15 minutes to check for heat-creep.
 

About the picture of the 3 blade prop and motor and LWPLA... I can imagine structural stress in that thin LWPLA tube. It is acting like the fuse for a normal tractor setup.

Somewhat better if that tube could be double walled with a bit of infill. And that is still asking a lot of it. What I am imagining inside that tube is a modified wing rib that extends forward to the motor mount/firewall in normal PLA or even balsa.  If there were one or two CF spars in that sort-of-flying-wing that modified rib would have something to tie into.

To be honest I was amazed at the strength of the LW-PLA. It does have a couple of internal formers to give some crush resistance.
What I would love to be able to do is to loft the tube so it ends in a shape that matches the skin of the fuselage body on the ground it would transfer the loads directly over a large area of the foam skin.
In principle for light weight structures if the skin is strong enough to carry the loads then concentrating the forces into a few structural members is heavy particularly if the load is then transferred back into a skin.  The V173 will have LW-PLA motor nacelles and a basically hollow body with a 3mm sheet foam skin. Once a suitable method is achieved to do this the next big problem will be the high stress points from that "stalky" undercarriage.   

Just in case I have done some work on motor cooling to give both an inlet and outlet.
A comparison of the two nacelles
 
On the nearer cool arrangement the spinner iis 1mm smaller.diameter than the motor so there is a narrow circular inlet facing directly forward.
The exhaust  is flush with the nacelle but of larger area.
 
I will have to do some timed run tests to see how effective the cooling is.

I have started looking at the "pancake" fuselage. With the 10" props to scale it will be tiny! 
The span of the pancake will be350mm (13.875"). Its length 360mm (14.1875") . The total span over the tail planes 525mm (20.625"). Width to clear the prop tips is even bigger at 564mm  (22.25").
At this stage I can only guess its likely weight 450g (16oz). With a wing area close to 1 sqft giving 16 oz/sqft. Most definitely not a slow flyer! 
 The 2822 1200kv motors at 40g are too heavy and powerful for the wing area. Then there is another 30g for each 10 x5 three blade.
Hmmm...... 

To attempt to solve the weight issue I have ordered two light weight 1200kV motors. They will be coupled to 11x3.8 SF props. True scale diameter but only 2 blade. I have even managed to find a CCW version. The SF prop is less than half the weight of the 3 blade.
The result will be that both lightweight motor/prop/nacelle units will weigh less than just one of the 2822 + 3 blade ones.
If it all works out although the power will be much reduced the final actual thrust to weight should be pretty much the same.
The next issue is how to connect up the controls. The big "elevators" between the rudder seemed to have none to effective except on landing where full up significantly reduced the ground effect of the pancake at touch down. The inflight photos of the V173 seem to suggest that the all moving "tail planes" were the major flight controls for both elevator and roll control..Perhaps they should be used as elevons in conjunction with the rear elevators.
I am sure that with such a small span tailless low aspect ratio layout an acceptable level of control will not be easy and even less likely right first time!          

The ultimate small motor big prop
1 
The 22mm BR2211 with an 11x3.8 SF prop.
To mount the motor I need to take off the motor mount.
 
The only problem is the grub screw is very small. Smaller than the grub is the prop driver is 1.3mm for which I do have an Allen key
I had to order a set of micro keys!

I spent most of Sunday in Warrington General after I managed to collapse on the kitchen floor as I was getting my breakfast cereal. My son heard me fall and my wife rang for an ambulance.
I was out for about a minutes but fairly quickly was able to sit up only to given the phone to answer all the questions from the 999 operator. Said an ambulance would be 45 minutes but it actually turned up in 10. Amazingly I had absolutely no bruises from the fall on to the tile floor The paramedics were very thorough with a n ECG and blood pressure as well as some arm & head movements to detect if I had had a strike  They said there were no obvious symptoms so recommended I go to hospital for a more thorough check, Over 6 hourss they did it all again including a set of blood tests. Finally the doctors conclusion was it was likely an episode of low blood pressure but otherwise all the results showed very similar result to those on my record so sent me home!
Oh! Well never mind all part of getting old.

One pension less to pay, more money for the boat people, they could stop them mid channel if they wanted to
Turn back or we sink you where you are
After a few of them went down others would not be so keen, also stop giving them money, phones, houses,free heating
The bloody French dont give them anything, they live in makeshift tents