Mini Arrow - 2nd plane...

[bazsound]

Update - Successfull mainden!!
Updated info 4th october 2017

Hobbycraft foamboard while being asmuch as 50% heavier than flitetest stuff works fine, it even flew great with the prop backwords .

This build including electronics weight 325g with an 850mah 3s batter. Balance was close enough fully forward.

hobby Craft foamboard £3 a sheet or 5 for £10. Number of sheets required 1 full sheet and part of a 2nd sheet.

electronics used

£5 https://hobbyking.com/en_us/be1806p...8sAtXeoSc5HiI3AJQm8aAoYqEALw_wcB&gclsrc=aw.ds

£3 https://www.ebay.co.uk/i/2530574489...=1007315&device=c&campaignid=207297426&crdt=0 (not recomended suspiciously cheap, cant be calibrated and no throttle safty, motor will initilize and spin up if you power up with throttle above 0)

£3 x 2 https://hobbyking.com/en_us/turnigytm-tgy-1440a-analog-servo-v2-0-8kg-0-10sec-4-4g.html (1 of my servos has a bit of play.. recomend a better servo)

£2 Aerostar Composite Propeller 6x4 (CCW) (cant find link)

£6 https://www.banggood.com/Tiny-Frsky...DIY-Micro-Quadcopter-p-1079963.html?rmmds=buy (D8 mode no modelmatch/receiver number)

Control rods - BBQ skewers with an old 450 heli control rod cut up for the ends and heatshrink + CA glued in place
Control horns were left overs from my yak 55, There meant to be screwed in place, but you can cut the flat piece off so it can be inserted into a slot and glued in place.

total Cost was under £30


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Ive been a heli pilot flying 3d for the last few years.\



REcently decided to try planes, my first plane was a cardboard yak 55 made from the heaviest card i could find (a TV box) it flew one for a short brief period before landing heavily on the ground. I gave up on that after several broken props. moved to a fomaboard version (heavy foamboard) flew 2 batteries and burnt out motor (overproped) ive now got suitable motor but broke another prob (have a habbet of nose firsting into ground when doing 3d)


So finally just ordered remaining bits for FT mini arrow, ive already bult the frame. just needs electroncis. ive went with HK stuff as lack of funds.. but it should be comparible to FT power packs.

Hpopefully i get more than a few flights before needing to repair as its getting frustrating going out and having 2 minutes and heading back in.

 

[rockyboy]

HK stuff should work just fine for getting an Arrow up in the air - and it's a heck of a lot more economical in the UK from what I've seen. Did you build the frame with the heavier foam board, or did you end up with a FT kit? If it's the heavy stuff you're using, check out some of the posts of advice from Hai-Lee here on the forums - he's a wealth of information for getting great results through tweaking things for the heavy board.

 

[bazsound]

HK stuff should work just fine for getting an Arrow up in the air - and it's a heck of a lot more economical in the UK from what I've seen. Did you build the frame with the heavier foam board, or did you end up with a FT kit? If it's the heavy stuff you're using, check out some of the posts of advice from Hai-Lee here on the forums - he's a wealth of information for getting great results through tweaking things for the heavy board.

yes its the heavier foamboard thats availible from hobbycraft (west foamboard) my yak 55 ended up at 350g flying weight, although it does fly but its a bit of a wing rocker if your not carefull. have had some success with my yak although being heavy i keep having to repair it from hard landings.

The mini arrow ive built is a bit better weight wise at 170g without electronics, once i add electronics i think its going to be about 250g including battery.

 

[bazsound]

Finally got my tiny frsky recievers (not sure what model they are, bangood just list them as D8 compatibl 4ch receiver) they came with the servo headers seperate so need tobe soldered on unless you want to hard wire your servos.

anyway, should hopefully get this ready for maiden midweek, i got the motor installed already and the servos test fitted before the receivers arrived. Didnt have any suitable wood for firewall so used an old plastic card, cut out 2 peices and sandwiched with hotglue. Seems solid enough.

Just need to install control horns, silly me forgot to mark transfer the mark for where the horn innstalls on the aierlon... whoops.

 

[bazsound]

Yep its ended up heavy... 320g

Although despite it being heavy it seems to be balancing if im measuring it right. 1.75 inches from the firewall. Ill need to measure it and put a mark on the wing but by looking at it it looks like its close. could just be maybe a tad tail heavy/

ve got an oversized heavy ESC which doesnt help. its a cheap "simonk" 30A speed controller. Ill change that for a smaller one later but the weight saving there would be at best 20g

 

[bazsound]

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finished build and coloured with sharpie. wuick radio setup on taranis with 30% expo and 100 and 60 rates. justneed toadjust to get full throw by going out 1 onservo horn.

otgetting asmuch thrust as i though i would. according to data on similar motor shouldbe 400g. it willnot take off or climb vertical.

 

[AkimboGlueGuns]

The nice thing about the arrow is that you will probably not even notice the extra weight. It's a super floaty design when it's built light, so at this weight it should still perform just fine.

 

[bazsound]

Well the maiden was a huge success especially since ive never flown a wing type plane (although i have had a few goes in the simulator so knew what to expect.)

Even managed to hand launch it fine the first time, i just gave it a little chuck like throwing a frisby at an angle up and off it went, it did suddenly roll right on be and dive to the ground but i got on the controls to pull it back up. Hand launch must have been around 3/4 throttle.

Now... its much slower than i thought, even at full throttle. is that why the 1806 motor is suggested?

https://hobbyking.com/en_us/quanum-...-brushless-multirotor-motor-built-by-dys.html

this is the motor i used, no test data, but i did look at another 1806 motor that starte with a 6x4 prop should produce 400g of thrust. Mine wont hand launch or clime vertical, im at 320g flying weight , 400 i dont think would be enough to takeoff vertical but it should feel like is pulling up slightly when holding?

I am having trouble with the esc though, the first inch of stick travel is dead space, it wont calibrate either, if i power up with full throttle the ESC initises and then spins up fast.

I want to change ESC anyway 30A is too big for this wing. 20A is more reasonable


Dont try and launch when the winds pick up, although this can handle winds fairly well big gusts make it really hard tohand launch.

i gust cought me on the third flight flipping the plane nose down and bellie facing, an impossible orientation for me to correct (might even have been to low even for an experienced pilot to correct) killed the power, anotehr gust cought it and sent it cartwheeling allong the gras.

This broke of 1 stabiliser, and the glue along 1 side of the cabin let go, quick fix though.

 

[Christopher14]

From those pictures I think your prop is on backwards. If your prop is on backwards, you're not going to get any kind of clean thrust; you end up with a massive whirring sound and a lot more amps drawn. The rule of thumb is the numbers of the front of the prop face the direction of travel.

 

[bazsound]

From those pictures I think your prop is on backwards. If your prop is on backwards, you're not going to get any kind of clean thrust; you end up with a massive whirring sound and a lot more amps drawn. The rule of thumb is the numbers of the front of the prop face the direction of travel.

your absolutly right! I Turned the prop around and all of a sudden it now feels like it will shoot off like a rocket if i hold it vertical, and makes a much cleaner sounding whine...

Should have known, i tried turning a prop round on another foamie when instead of reversing the motor and on that prop it produced no almost no thrust.

Thanks! about to head out to test it out now it has proper thrust!!!

 

[bazsound]

Need to know if im going to have increased response from elevons, the 2 flights i had with backwords prop it would aileron roll REALLY slowly. Although flying circuits was very easy so i dont think lack of through is an issue, i was just under 12 degrees , ik then moved out one hole on the servo and also on the control horn on the control surfaces. so im probably just over 12 degrees now.

Hoping to test fly in the next couple days when the wind dies down just dont want to suddenly find its now super twitchy and smash it into the ground

 

[bazsound]

Need to know if im going to have increased response from elevons, the 2 flights i had with backwords prop it would aileron roll REALLY slowly. Although flying circuits was very easy so i dont think lack of through is an issue, i was just under 12 degrees , ik then moved out one hole on the servo and also on the control horn on the control surfaces. so im probably just over 12 degrees now.

Hoping to test fly in the next couple days when the wind dies down just dont want to suddenly find its now super twitchy and smash it into the ground

 

[bazsound]

So with the prop on the correct way im not noticing any difference really in speed, although it does seem to fly on less throttle and launches a little easier.

its a bit unstable though with it tending to sudenly rocks its wings. and when doing slow passes it seems to sometimes yaw left right.

Mines i dont understand seems to be nose heavy. i built a balancing stand and it looks to be balancing at over 2 inches infront of the firewall. move the battery asfar back as possible. its almost on the CG but it requires lots of trim to stop it nosediving into the ground. Ive added weight to the vertical stabilisees to bring it back to half in inch...

 

[bazsound]

Ok another few flights. I rebalanced the plane. Marked 1.75 inches infront of the firewall and found that i was actually at 1inch. got it close to the mark and it flew like crap. nose dived to the ground on launching and i didnt have enough trim. it was always yawwing left right in slow flight and just generally unstable.

So i removed my weights and went back further to the firewall, this was much much better, the yawing had gone, the wing rocking was still there however much much more predictable and was probbaly just the wind. it also seemed to fly a little faster. however i still needed more trim than i had to stop it nosing into the ground.

On landing i belly floped it, probably due to having to hold up elevator all the time, i let go and it suddenly flopped onto the runway short of where i was aiming for (grass) it broke 1 stabliser and a small chunk on the top lifted up oh and broke my only prop (cant find my spare)

Im confused at what is happening do i not have enough reflect? Used the gauges ill recheck.

still finding the roll rates pretty slow

 

[Hai-Lee]

Ok another few flights. I rebalanced the plane. Marked 1.75 inches infront of the firewall and found that i was actually at 1inch. got it close to the mark and it flew like crap. nose dived to the ground on launching and i didnt have enough trim. it was always yawwing left right in slow flight and just generally unstable.

So i removed my weights and went back further to the firewall, this was much much better, the yawing had gone, the wing rocking was still there however much much more predictable and was probbaly just the wind. it also seemed to fly a little faster. however i still needed more trim than i had to stop it nosing into the ground.

On landing i belly floped it, probably due to having to hold up elevator all the time, i let go and it suddenly flopped onto the runway short of where i was aiming for (grass) it broke 1 stabliser and a small chunk on the top lifted up oh and broke my only prop (cant find my spare)

Im confused at what is happening do i not have enough reflect? Used the gauges ill recheck.

still finding the roll rates pretty slow

Understanding the responses to differing CG positions on a flying wing takes a bit of experience as the responses can be difficult to understand.

Simply put if the CG is too far aft the wing will wander in yaw very badly and even viciously drop a wing if the rewards location of the CG point is excessive. The yawing is made worse in a swept wing because of the "Dihedral effect" of the wing sweep.

When the CD is too far forward the wing will, "bounce?", the nose rather severely which is due to the Nose up, Stall, Nose drop, build up speed, nose up and so on! Ideally you can set it for the bounce is at its minimum but do so in small steps.

Once the wing is flying stably, then adjust the amount of reflex to give steady level flight with trims centred.

Roll rates can be a little slow without severe control surface deflections because the wing sweep has a "Dihedral" type of effect and the wing area itself is rather large in area.

If you are skilled with transmitter setup you could increase your control surface deflections and use the mix ratios in your transmitter mix setup to give more balanced flight maneuvers and control responses.

Simple version: Adjust CG for a little "Bouncing at stall. Then adjust reflex for level flight. Adjust control deflections for maneuverability. Adjust mix ratios for balanced control responses.

Hope that helps.

 

[bazsound]

Understanding the responses to differing CG positions on a flying wing takes a bit of experience as the responses can be difficult to understand.

Simply put if the CG is too far aft the wing will wander in yaw very badly and even viciously drop a wing if the rewards location of the CG point is excessive. The yawing is made worse in a swept wing because of the "Dihedral effect" of the wing sweep.

When the CD is too far forward the wing will, "bounce?", the nose rather severely which is due to the Nose up, Stall, Nose drop, build up speed, nose up and so on! Ideally you can set it for the bounce is at its minimum but do so in small steps.

Once the wing is flying stably, then adjust the amount of reflex to give steady level flight with trims centred.

Roll rates can be a little slow without severe control surface deflections because the wing sweep has a "Dihedral" type of effect and the wing area itself is rather large in area.

If you are skilled with transmitter setup you could increase your control surface deflections and use the mix ratios in your transmitter mix setup to give more balanced flight maneuvers and control responses.

Simple version: Adjust CG for a little "Bouncing at stall. Then adjust reflex for level flight. Adjust control deflections for maneuverability. Adjust mix ratios for balanced control responses.

Hope that helps.

Thanks ive got a few things to try now.

I might actually build a 2nd one with the paper removed and use tape on one side, the west foamboard upto 50% of the weight is in the paper, if i remove that and reinforce 1 side with tape and maybne use filiment tape as a strap ill get closer to the target 170g without battery.

Im just confused at why it isnt working well at the recomended CG, is the wing loading too high?

 

[Hai-Lee]

The most common reasons for CG not being exactly where it should be is the wing profile itself and the wing builld quality, (warps, twists, and even Elevon warps. Of course being over weight can make matters even more obvious or worse.

Get what you have flying and use all you learn to make the second a far better machine.

have fun!

 

[bazsound]

The most common reasons for CG not being exactly where it should be is the wing profile itself and the wing builld quality, (warps, twists, and even Elevon warps. Of course being over weight can make matters even more obvious or worse.

Get what you have flying and use all you learn to make the second a far better machine.

have fun!

Im at 325g (no fpv gear) . im also running the 1806 motor with a 6x4.5 prop after more research i seem to find that the 6x4.5 prop is for the 2204 motor, hwoever my motor isnt getting hot.

Maybe my elevons are warped, i used the guage to setup the deflection so they should be the same, but they do not look the same. also it seems that 1 elevon deflects more....

One other thing.. what about the wing tip stabilisers. I did knock them off and had to glue them back on, does the positioning of those make a difference, ie if you dont get them euqal top to bottom ie tyiou have more stabiliser above the wing than bellow.

oh i forget yeah on half of the wing has 1 less fold than the other. One of my score lines wasnt deep enough, so one side has 3 distint lines and the other is 2.

 

[bazsound]

I broke a prop on the last flight when i belly flopped it on tarmac... was just checking my HK account to see what props i had ordered. Turns out i have a slowfly 6x4.5..... Is this maybe reason for the slower flights? i know slowfly props are not rated for higher RPM so is the prop just flexing and becoming inefficient at high rpm??.

anyway ive ordered regular 6x4.5's aswell as a 1000mah 3s battery to try (my 850s are over a year old and the IR seems to have risen)

 

[Hai-Lee]

Just one other thing that I forgot tomention on my earlier posts is that having elevons that are easily twisted or somewhat soft and flexible can give poor deflections at maximum speed leading to very poor roll and loop responses as the elevons will tend to flatten out due to the twisting of the control surface. I give mine a good coating in Miniwax or equivalent to stiffen them up.

have fun!