Van's RV3

[John Timmis]

Hi Folks

Latest thing from the workshop is a Van's RV3. Basically it is Peter Millers design ( freebie plan from a couple of years back) enlarged 25% & converted to electric.

I don't like to have an empty building board for too long. With the Hurricane finished,but still not flown, I decided that what I needed was a straightforward scale model (no fussy detail) , robust & with a good strong U/C, about the same size & weight as the Hurricane & using the same 6s batteries.

This is what emerged. Not much needed to be changed but there is a closed loop rudder linkage & homemade rotary drive for the flaps, undercarriage can be removed for straightening out if necessary.

Power train consists of: Ripmax Quantum II motor, 80amp esc, 6s battery, 13x4 prop. On a fresh battery it gives 1360watts. Weight is a tad under 9lbs.

Hopefully first flight is tomorrow. Pilot looks a bit pale but then she has never flown before & hasn't had time to put on her make up either.

Fingers crossed ( thanks Peter)

Cheers John.

[John Timmis]

Hi Folks

So how did it go then?

Too exciting by far. More of a first "FRIGHT'.

Saturday morning , batteries all charged ,nice day; what could possibly go wrong?

Well the flight proved two things: there was plenty of power & the c/g was too far back. It really was uncontrollable but was gaining height fast. At fair height the motor was throttled back & I managed to find a rather twitchy trim which enabled one circuit of the field & a safe landing with no damage. Luck was certainly on our side.

So back in the workshop, the flight battery has been moved forward 6" & the ESC relocated above the battery. It's a bit cramped bot it all goes in, just.

Move forward to Wednesday. Now how does it go? In a word BEAUTIFUL. Changed a tiger into a pussy cat. Your Grannie could fly it now.

Looking forward to lots more flying. Very lucky to get away with though. I must have been a very good boy recently.

Cheers John.

[Nigel R]

Looks ace!

" homemade rotary drive for the flaps,"

do you have any further details on the rotary drive?

the front end looks really neat - how is the motor accessed, is it from behind or does the big spinner allow you a big hole to get it in through the front?

[Levanter]

Yes Please John
Rotary drive for the flaps.

Levanter

[John Timmis]

Hi

Nigel, Levanter thanks for the replies.

The motor is accessed through the hole behind the spinner, you just need a long Allen key. The motor is fully enclosed . I did make an extra cooling slot in the bottom of the cowl for the motor. I was glad of this when, having fitted the prop & spinner, I came to unscrew the prop nut & the motor spindle turned with the nut & the motor could not be held. Fortunately ,It was possible to insert a length of hardwood through the cooling slot to engage with the slots in the motor casing.

The wing has 2 servos in the center section, one to drive the ailerons via bell ranks & the other to drive the flaps via pushrods & rotary drive. I did it this way because: I already had suitable servos, I wanted to avoid a very long horn on the flaps ( necessary because they are bottom hinged), I like to try new ways of doing things.

I didn't take any photos of the build so I can't show the installation. The drive was cobbled together from bits that were in the workshop ( brass tube , piano wire, couple of collets, Paxolin for the flap boxes). it all works well, the essential things are that the bend in the torque rod must line up withe the flap hinge pins, the torque rod must be a good fit in the flap box.

The photo shows the working pieces, the flap box is 2 rectangles of paxolin separated with ply spacers, I think the torque rod was 14swg, don't make it too long.

Hope this helps. Good luck if you try it.

Cheers John