2m f3a own design. Myvec
#1

Thread Starter

Hi im Dan, first post on here. Based in the uk.
Going to do a bit of a thread on my new project for this year. I drew it up autumn last year but a new baby arrived in october so been a bit too busy to get it started.
However, baby no.2 is behaving itself so i thought id have a go at getting this thing flying!
Having flown a Spark (with Dave Snow wings) the back end of last season, i really liked the way it performed so decided to loosely base this design on the Spark. I also like the Agenda/Element/Invitation/Essence models so a bit of those designs feature too. Mainly fuz depth! Dont know if its as deep but pretty close.
Everything is pretty conventional (is an all wood f3a model conventional), no all moving tail, no retracts!! And 1 wing.
I'll be using the TMCR contra unit made by Adam Debowski. More on that later.
Wood selection as always is going to be important, the fuz is big and will take a lot of sheeting!
Dont know how i got the name Myvec but thats what its called.....at the moment
Anyway, heres some photos....
Going to do a bit of a thread on my new project for this year. I drew it up autumn last year but a new baby arrived in october so been a bit too busy to get it started.
However, baby no.2 is behaving itself so i thought id have a go at getting this thing flying!
Having flown a Spark (with Dave Snow wings) the back end of last season, i really liked the way it performed so decided to loosely base this design on the Spark. I also like the Agenda/Element/Invitation/Essence models so a bit of those designs feature too. Mainly fuz depth! Dont know if its as deep but pretty close.
Everything is pretty conventional (is an all wood f3a model conventional), no all moving tail, no retracts!! And 1 wing.
I'll be using the TMCR contra unit made by Adam Debowski. More on that later.
Wood selection as always is going to be important, the fuz is big and will take a lot of sheeting!
Dont know how i got the name Myvec but thats what its called.....at the moment
Anyway, heres some photos....
#3

Thread Starter

Yes thats the one. They're a great bit of engineering but very simple when you break it down.
I'll put up more photos of the install when i get to that stage.
Dan
I'll put up more photos of the install when i get to that stage.
Dan
#4

Thread Starter

Bit more done last night. Its very fiddily and delicate at this stage but pretty close to sheeting now.
I pinned the bottom decking on just to see what it looks like, its pretty big. Ill remove this and pin it to the board to sheet it.
Its hard to see in the pics but on the rear half of the fuz on the bottom is a removable keel. Will be interesting to see how it effects the flying- if at all.
Dan
I pinned the bottom decking on just to see what it looks like, its pretty big. Ill remove this and pin it to the board to sheet it.
Its hard to see in the pics but on the rear half of the fuz on the bottom is a removable keel. Will be interesting to see how it effects the flying- if at all.
Dan
#6

Thread Starter

Thanks. I can only work in 2d, havent learnt 3d yet. Its has its limitations but works ok for what i want. I'll try and get some side and top profiles.
Yes ive used 3mm carbon tube for the diagonals on the top and bottom crutch. Very light and adds a lot of torsional stiffness.
Yes ive used 3mm carbon tube for the diagonals on the top and bottom crutch. Very light and adds a lot of torsional stiffness.
#7


Is this the Contra you are referring to?
It looks like a Q80 with a Contra added on? Very different looking.
https://www.youtube.com/watch?v=XE6-MLe2bWc
It looks like a Q80 with a Contra added on? Very different looking.
https://www.youtube.com/watch?v=XE6-MLe2bWc
Hi,
It looks like two motors with the front one having a hollow shaft and the rear driving a narrow shaft that passes through the front motor.
Two ESC's req'd !!
Weight ??
Brian
#8

Thread Starter

Hi Brian yes 2 motors 2 escs. I will weigh it (its currently in another model) but its not heavy. Each esc is smaller (60a size approx) than a typical 100a and theres no gearbox/ belt drives with mounts etc to deal with.
Theres also only 2 moving parts, no maintenance required.
Theres also only 2 moving parts, no maintenance required.
#9

Thread Starter

Took the TMCR out of the other model, the 2 motors weigh in at 732g. With the 2 props and 2 esc's its 912g.
When im the stage of being to mount the motors i'll do a step by step of how its installed.
When im the stage of being to mount the motors i'll do a step by step of how its installed.
#12

Thread Starter

The Adverrun with props and spinners is approx 770g?? Add on an esc approx 140g thast 910g. That might be heavy too i dont know, i've not had much experience with contras.
Started the sheeting now, easy bits first, i'll have to plank the nose which i dont like doing :-(
Started the sheeting now, easy bits first, i'll have to plank the nose which i dont like doing :-(
#14

Thread Starter

Ah i tend to include the esc's with this contra as you cant really use them with anything else.
The designer (Adam debowski) has also modified each esc to give a constant rpm at any throttle input. i.e if half throttle is say 2500rpm, it will stay at 2500 rpm if its climbing/diving/straight and level etc.
I think hacker are developing something similar or may even have it out now, not sure.
Dan
The designer (Adam debowski) has also modified each esc to give a constant rpm at any throttle input. i.e if half throttle is say 2500rpm, it will stay at 2500 rpm if its climbing/diving/straight and level etc.
I think hacker are developing something similar or may even have it out now, not sure.
Dan
#16

Thread Starter

More done today, planking the nose was a pain but it turned out ok.
Fin worked out well also, mainly thanks to a technique i borrowed from Adrian Mansell on the gbrcaa forum
Fin worked out well also, mainly thanks to a technique i borrowed from Adrian Mansell on the gbrcaa forum
#19

Thread Starter

Thanks Will, i havent really thought about kitting it yet, we'll see how it flies first i guess!
Heres the link to Adrians build thread (Lepton), very interesting thread, great flying plane too.
Lepton Build Thread
Heres the link to Adrians build thread (Lepton), very interesting thread, great flying plane too.
Lepton Build Thread
#21

Thread Starter

Done most of the horrible bits now. Finished the bottom planking, its ok, bit of filler needed but i can live with it.
Cut the canopy off, came of ok and has come out very sturdy. Which is good as it will add to the rigidity of the fuz.
Still a bit of facing to do on the canopy and put the latches on, cut and face the rudder and the fuz is pretty much there.
Cut the canopy off, came of ok and has come out very sturdy. Which is good as it will add to the rigidity of the fuz.
Still a bit of facing to do on the canopy and put the latches on, cut and face the rudder and the fuz is pretty much there.
#23

Thread Starter

Thanks Alex, i've used 2.4mm (3/32") contest grade. A 36"x4" sheet is averaging about 17g.
Makes a big difference on the final weight. I've bought 50 sheets for this build, if each one was soft to medium grade @ 27g ish, it would be 500g heavier. Which is a lot.
My last 2 f3a planes (an own design and a krill spark) tipped the scales 5kg with relatively light turnigy 5000 lipos. After a while the lipos started to struggle so if i can get to a weight of about 3500g, i can use some higher capacity lipos.
Makes a big difference on the final weight. I've bought 50 sheets for this build, if each one was soft to medium grade @ 27g ish, it would be 500g heavier. Which is a lot.
My last 2 f3a planes (an own design and a krill spark) tipped the scales 5kg with relatively light turnigy 5000 lipos. After a while the lipos started to struggle so if i can get to a weight of about 3500g, i can use some higher capacity lipos.
#24


Yes balsa selection is very important. Your balsa is very light; my sheets have different dimensions, but it looks like the calculated equivalent weight is about 6g heavier.
#25

Thread Starter

Got the fuselage pretty much finished today, canopy on, rudder cut out, faced and hinged. The only thing left is the sleeve for the wing tube.
Really happy with the weight, its come out at 912g with the canopy and rudder which i reckon is pretty good considering the size of it!!
Anyway, heres some pictures....
Really happy with the weight, its come out at 912g with the canopy and rudder which i reckon is pretty good considering the size of it!!
Anyway, heres some pictures....