Can Doo it

[Stuphedd]

This evening I decided to do a bit of nose grafting myself , so I mocked up an individual canard set up . And yes as a previous contributor said there was not enough room inside , so the mechanism is external !! (well you dont know till you try !!!)

so into the bin box to see what we have .

carbon rod look in golf course trash cans , cos good brollies have lots of carbon rods and they are free !!

ally tube , the verticals off an old TV ariel

"horns " off old push rod angles for ailerons .

job done

So the next job is to remove the standard frond end of my Can Doo and fit the mods !!

cheers

[Stuphedd]

Oh and I nearly forgot , Torque roll ,Normally at Take off there is not sufficient air flow for ails to be very effective , and they tend to "suddenly " become live , so rudder was always the prefered. If there is no rudder then Ails are the only option !! best of luck .

Think about when you land ,to steer it in you use your rudder , why ?? cos the ails are a bit soggy ,

cheers

[Stephen Jones]

Hi Pete ,

With all this bad weather we are having i have not been able to get out and test fly mine and in my workshop i have a large sheet of 5mm Depron and two large sheets of 3mm Depron ,

So i am considering making one more Can Doo out of Depron what size did you use ?.

I am also toying with the idea of making the foreplane as a swing wing , my thinking is the faster you go the more lift from the fore plane so the plane pitches up but if i swing it back there will be less lift and so keep level flight .

Always thinking ,

[Stephen Jones]

Thats right pete also you would set the motor to have right thrust to couter act left torque ,

if it is a puller that is , so if the motor is at the back look at which way the motor is running and the torque will be in the oppiste direction so you need the motor pull to counteract this .

[Stuphedd]

Hi Steve ,

I used 6 mm Depron all over !

I used Gorilla glue to stick it , bit of a sod to clean up the plane after wards , but its quick and does an excellent job

I use furry hinges again put in with Gorilla glue with a bit of re inforced sellotape around the hinges and horns .

ally spars for the wing and canard and a couple down the inside of the fuz for longerons .

a swing wing canard !! well thats novel !! it will prove interesting ,

Now should we build a Can Doo with a purposefully removable nose section so we can try out these mods easily ??

cheers

[Stephen Jones]

Posted by Pete Willbourn on 25/02/2014 23:11:08:

Now should we build a Can Doo with a purposefully removable nose section so we can try out these mods easily ??

cheers

Can Doo it ,

[Stuphedd]

I have been persuaded that it would not be in anybodies interest in modding the "old " airframe , so Its a new one to try the all flying canards on .

been out all day so very little progress other than completing the 2 fuz sides ,

with all this bad weather I shallbe running out of Gorilla glue

pete

[Dave Coleman 1]

Hi steve so if it torque rolled to the left i need washers on top left of moter mount to counter this? Also elevator on foreplane goes down for up??? Thanks dave

[Stephen Jones]

Hi Dave ,

Lets start with the easy one 1st , Foreplane controls pitch by generating more or less lift , (In a lifting canard ) which the CanDoo is .

A wing will give more lift if a control surface is lowered at the rear of the wing ( flaps are used to give more lift at lower air speed ) .

So in a conventional aircraft the elevator is raised which in turn pushes the tail down ( negative lift ) and as everything rotates around the CoG this causes the front of the aircraft to pitch up .

On a canard we have the elevator at the front so it action is reversed , so now when we raise the elevator at the foreplane this forces the nose down and the tail up .

Hope this helps on point 1 .

Cheers Steve .

[Stephen Jones]

Hi Dave ,

Point 2 ,

Torque roll is a complex one as there are varied effects at different speeds of both the motor and aircraft and control surface.

So i will try to explain as best i can on what i believe is going on . So i may well stand to be corrected .

Ok remember that everything rotates around the Cog , and newtons Law where every action has a equal and opposite reaction .

So if the prop is spinning clockwise the plane will try to rotate anticlockwise . the faster the plane is moving the less of the effect is noticed due to the spinning air being stretched and so less acting force. and as this moving air generated by the prop is rotating as it moves along the body of the aircraft it will be acting on wings and fins pushing against them from one side only .

So to counteract this we need to compensate by use of the Ailerons , But the Ailerons have very little effect at low speed which is when the torque effect is most prominent . So we have to use Rudder as well .

On a aircraft that has it`s motor at the front and the prop is spinning in a clockwise direction , which forces left torque ( left turn ) we would normally set the motor with right thrust to counteract this , so as to reduce the amount of rotating air running down the length of the aeroplane .

But remember that everything rotates around the CoG so if the Motor is at the back of the plane we need to reverse are thrust line ,

But remember we are using electric motors so we have a few advantages that we can use , we can reverse the motor and use a pusher prop and we can reduce the size of the prop all will have varied degrees of effects .

Also remember that aircraft usually take off from the ground building up speed slowly which allows the torque effect to be damped out . But we are hand launching from zero air speed to high speed so it is best to ease the power in slowly .

This is also the reason why we can over prop a plane , so sometimes less is better than more .

Its all very well being able to go very fast but if it make the aircraft uncontrollable at low speeds is it worth it .

Hope this Helps, Steve ,

[Dave Coleman 1]

Hi steve thanks for that on both points we are already using a pusher prop think i will reduce the size of the prop and try that as for the forplane we had read on ere about down for up but was unsure but i had got it set that way thanks again dave...

[Stephen Jones]

Hi ,

On apc props a tractor prop will have the size only on it 6x4

where as a pusher prop will have the size plus the letter P so 6x4P .

[Stuphedd]

I must admit as to never having used a "pusher " prop on electric, , I only use pushers on my IC aircraft where reversing the direction of rotation is usually difficult ! . and they are usually more expensive !

So whats the difference between a prop going anti clock at the back of an aircraft and one going anti clock at the front ?? (advantagewise ??) do we really need pusher props ??

Pete

pics of the "new one" on their way shortly

[Stuphedd]

[Stephen Jones]

Posted by Pete Willbourn on 28/02/2014 08:40:15:

I must admit as to never having used a "pusher " prop on electric, , I only use pushers on my IC aircraft where reversing the direction of rotation is usually difficult ! . and they are usually more expensive !

So whats the difference between a prop going anti clock at the back of an aircraft and one going anti clock at the front ?? (advantagewise ??) do we really need pusher props ??

Pete.

Yes we do .

Which is easier take the model apart to add right thrust or swap the prop for one that goes in the opposite direction .

Did you know that some motors perform better in one direction than an the other . Try it with a watt meter simply run you're motor up record you`re watts then take the prop off and put it back on backwards reverse the motor and record the watts . Now what happens if you find it does run better anti clockwise .

Do you re design you model so that the motor is now at the back of course not you get a pusher prop and use that .

Also it is far better when flying a twin model to have one motor going clockwise while the other goes anti clock wise .

And if you have a push me pull me model you can cancel out any torque by having the motors going in opposite direction to each other .

Being able to reverse the motor is only one advantage a choice of props is an other .

[Stuphedd]

I dont disagree with anything Steve has said , I have not tried the reverse rotation amps exercise , but I always use an ammeter on all my installations .( I shall do that test ASAP)

I do tend to mount my motors so that the prop kinda balances the rotor , ie from the base with the prop on the base side , This is because I feel balance of prop and motor is very important on leccy stuff , and with all good quality motors they have twin stack bigger diameter bearings in the base , Axi, Scorpion Hacker and some eflite .

This tends to help in the high gyroscopic forces that the motor and mounting are subjected to, if you fly like me !

On twins yes counter rotating is the obvious way to go , the Peggy engine in the Harrier had one rotor clockwise and the other anti clock which made hovering "easier /possible )

I can see the advantage of the push me pull you i, not quite sure what happens to the couple element ? is there one ??

However I did find a clockwise prop on one of my flying machines , but its at the front and attached to one of the counter rotation motors on a twin motor setup

But enough of that, today was so fabulous we went flying , And the all wood, all flying canard Can Doo had its first flight .

On its first flight it did torque roll to the left ( does this sound familiar ??), but its flying speed was dismally slow , and it took for ages for the ailerons to bite , so I aborted the flight as the fast approaching hedge was too high to climb over .

The second launch at full power , with a good heave and a tad of aileron held in , proved ok and a safe maiden was achieved . ( it still swung to the left but the ail held it and steered it out .

The model weighed 30 oz ! which I recon is heavy , it is smooth but not agile , there may be vids of it , I dont know yet . The lighter one is so much easier to fly , and mile , miles more agile !

cheers

[Stuphedd]

just a couple of pics today to show it flying

[Stephen Jones]

Hi Pete ,

Thats nice ,

I hope to get out with mine soon .

I set up the radio gear today on mine and test the motors Boy i think i am in for a real speed monster .

I held it vertically and powered up the motors it will defiantly go vertical and no sign of torque .

I am thinking of putting wheels on it , or maybe a dolly for the 1st few attempts un less i can find someone brave enough too launch it for me until i an sure of it .

[riverlandgirl.]

Hi Steve

Really looking forward to seeing how this goes! (Give the lad a welding glove!)

best of luck

[Stuphedd]

Best of luck Steve , !! fast it should be ! ( they look good in the air dont they )

The rudders were very powerful and you could induce a roll with them , but not enough height / nerve to complete one yet !!!

a couple of pics of my new one will follow

cheers

pete

[Stuphedd]

[Cliff Bastow]

Crashed mine yesterday!

Cant believe I was so stupid, I launched it and it got away fine, then it rolled slightly left so I fed in right aileron and it immediately completed a full left roll! i released the sticks and then fed in right aileron again and it rolled left inverted and then hit the deck hard and nearly vertical.

Damage is mostly front end smashed from the rear cockpit bulkhead forward but I think I can rebuild it.

On return to the pits the investigation started, Some of you are probably way ahead of me, yes reversed ailerons.

I did do a control check but must admit i only checked the ailerons were moving and not in the right sense, Basic mistake I know. I assumed because it had flown before that everything was ok. Lesson for us all there.

The only thing I cannot understand is how they got reversed between flights? I have not altered anything on the transmitter. I did wonder as I was playing around with another model set up the day before if I was not in the model I thought while I was setting it up and inadvertently changed the can doo instead. Strange thing is though the other model was set up ok.

Should have done full checks though.

[Colin Leighfield]

Tough luck Chris, I know how that feels! You'll soon sort it though, onwards and upwards!

[Stuphedd]

http://www.youtube.com/watch?v=M8HMvAidXGs&list=UU0-HJUo3QvBUwxCCoMg_aGg

I did not know if the Can doo was "vided" yesterday but it was , complete with launch !

lots of other stuff to watch over lunch break , ending with the BLom and Vos thing featured in RCM&E a year or so back , but this one is 1/3 bigger

enjoy it !!

I hope

[John Manning]

I had the self same thing happen on my Gym Star, indoor trainer. Fortunately I noticed it as the rudder had also reversed. They have stayed the same ever since.

Yesterday was a fab day, I went for a family walk and wished that I had revamped the foamy cub that I have.

John M