Foamboard Scratchbuild University - Page 393 - RC Groups
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Feb 21, 2018, 03:30 AM
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davereap's Avatar
here is another plan for you .. made from a single board..

The mini blitz was shown in the December RCM&E mag and is a nice sport delta design.
The original is a built up balsa wing, but a KFm2 will do the job nicely and is a much faster build..

Ive made mine using a B&Q underlay board, similar to the hobbyking aeromodelling foam..
The $shop board will work just as well.
There are a couple of the original , with two fixed fins .. and one with a single fin and rudder..
I went with a single fin..

motor a 2205/6-2280 quad type.. 3x 5gm servos.. 12A esc..
lipos 2s or 3s .. 450+ size.

AUW is at 7oz with plenty of thrust on the 2s.. 450..

Remove the paper from between the layers and laminate the wing,
I covered my foam from the front LE to the step with laminating film, above and below the wing .. then used more film to cover the fin/rudder and control surfaces ..
I hinge them to the wing with full length laminating film strips on top and small strips below..
The fuz and fins are fixed with UHU holding simple butt joints and then cool melt is used to add fillets into each side of all joints
More laminating film was used to cover and further hold the fuz to the wing

All shiny surfaces seen in the pics are a result of laminating film covering... It does add weight but makes the wing very tough and stiff..
In this case a lighter foam plus the film has given a great result....

I struggled in wind today but got the COG sorted.. this poor flight is down to the windy conditions, it will be great on a good day..
note the starting COG is 1" in front of the step line at the root and that is slightly nose heavy
electric KFm2 blitz on 2s 22feb2018 (7 min 4 sec)
Last edited by davereap; Mar 08, 2018 at 03:17 AM.
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Feb 21, 2018, 09:33 PM
Aka "DiveBomb"
I like the clean pod design, having the servos all center mounted keeps the wing area nice and clean.
Feb 25, 2018, 02:47 AM
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davereap's Avatar
These deltas are fun
try this one for 3D
Feb 26, 2018, 09:40 AM
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Originally Posted by davereap
These deltas are fun
try this one for 3D
done. I will be trying this!
Feb 27, 2018, 02:23 AM
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Giving the scratchbuilt university (in keeping with the original postings of this thread) mini ADP, since it seems no one who has built/flown this is around anymore its all been experimentation.

i had it flying but it just wanting to nose up and loop from about half power upwards. figured it waws a downthrust issue, ended up added 5 washers and it still wanted to loop, i then added a shim to the back of the canard to give it a few degrees angle to produce less left. this seemed to do the trick but it wasnt as fast as it was before.

Then i thought, maybe its the canard being all the way forward, on the mini apd video he scaled the full to 2/3rds size and mentioned added 4 inches to get more weight forward. He put the canard over the battery hatch but i put it fully forward like the fulls zie.

So this would mean the canard needs less lift as its a longer lever. I needed to buld a new fusalage tube so did it this way. The wierd thing though is that i dont need the extra nose length for nose weight, my battery was actually being pushed rearward closer to the middle to get it balanced.

Unfortnatly i made the mistake of going too tail heavy on a windy day, which sent it straigh tup on launch and backwords over the pits area and back further where i killed the power and it crashed in the car park!

then my yep 40A esc let the smoke out after adjusting it, the motor wouldnt turn properly , i think 1 phase failed, smoke came out one of the chips
Feb 27, 2018, 07:41 AM
used to build now i fly
i use throttle to elevator mix on many foam board planes it works out the climb and dive issues with throttle. as for downthrust it help in getting it as close as you can first then add the mix. i like to see the model fly with just enough power to maintain level flight and trim elevator at that then land and asses the amount of trim trying to add down thrust to remove as much as possible. then i go to mix mode and add a bit of up and low power and down at high power this with a bit of trials smooths things out very well.

in dx9 it is around 8% 8% with no offset this settings has worked as a solid start and often never needs changes once the above things are taken care of
Feb 27, 2018, 03:09 PM
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A mix in my case wont be a good fix as tthe climb at 3/4 throttle needed 50-60% down elevator to fly level.

At cruise not much was needed once t startes gwttjng apeed just started climbing amd xlimbing. So i guess is the canard too far forward.

The canard is big compared to other planez but ea flys fine
Feb 27, 2018, 04:24 PM
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I've been flying the ez canard and have changed the angle of the canard from 4 to 2 to 0 and haven't quite got i9t down yet, the 9 flies well til you drop the power, then things go bad, to land I had to go to low power and down trim or it would fall out of the sky, 2 degrees of angle works best it cruises at half throttle no problems when you cut the power to land , but when you go above half it will climb. I'm thinking that a kf 2 airfoil on the main wing might ease that problem a bit, the faster it life the more lift on both ends, also I think I'm over powering it.
Mar 01, 2018, 10:03 AM
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Any idea how much weight the minwax adds to the DTFB?

Originally Posted by jpot1
junmarD4th - you will first need to use oil based minwax to treat the DTFB paper. Brush it on so it gets damp and wipe off any excess. Once that drys the paper will take any kind of spray paint but still use light coats. I also recommend use hot glue to seal any exposed edges so the propellant does “eat” those areas.
Mar 02, 2018, 03:45 PM
Too old to rock-n-roll...
TooJung2Die's Avatar
Originally Posted by dropout
Any idea how much weight the minwax adds to the DTFB?
I weighed a sheet of DTFB coated with Minwax Wipe-on Poly (both sides): 121 grams. Untreated DTFB: 113 grams.

Mar 03, 2018, 09:20 AM
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Synapse Variation

OK. Here is my variation on the Synapse. Normal Synapse wing but with custom fuselage. Fuselage is made up of four carbon fiber arrows and a few custom 3D printed parts. Charging batteries to go and maiden it this morning.
Mar 06, 2018, 11:48 AM
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i just got one of these

and orange rx stablising flight controller/reciever. on an unrelated noted they are discounted now i guess thats why they were on sale. shoudl have bought 2.

BUT i didnt realise it was a micro one, so it uses micro molex connectors. I bought micro molex to normal servo cables connections. Jow much current can these things handle? its only powering 2 9g servos (anologue ones)

But it is going in the baby APD which runs of a 2200mah 3s battery.. AUW is 600g. Im sure its fine but worth checking . I can use it in my FT mini arrow which uses smaller servos and is much lighter ar under 300g with a 1000mah 3s battery.
Mar 13, 2018, 03:39 AM
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OK i think ive finally fixed my climbing issues on the baby APD. watch the videos properly, ED stated evewrything is the same as the full sized scaled down 2/3rds, and he added 4 inches to the fuselage to allow adding more weight in the nose.

Well that pretty much states where the canard should go, in his videos he had it over the battery compartment, and i had it right at the front, which makes the canard more effective.

had it out for its re-maiden with a new 60A (overkill but was on sale from HK) speed controller hs-55 metal gear servos (reploacing the cheap flimsy plastic geared ones which were probably not strong enogh) and an orange RX stabiliser.

The first flight was interesting to say the least, i used the canard CG calculator which told me to put the CG 15" back from the leading edge of canard. This put the cg on the main wing. Not trusting this i went further forward thinking at worse ill be nose heavy. WRONG as soon as i launched it (chuck then applied power) it went into a harrier.

Thinking damn its not fixed i kept the power on allowing it to climb and level out, then as soon as i touched the elevator it was super twitchy, slowed it down it became eratic so put the power on, it seemed to fly better with more speed but was uncontrollable in turns, eventially i manage to work it back as close as possibel and put it down.

No damage. Shifted the batteryh about 4 inches forward and it launched better, still slightly nose up but it was fliable, it still felt very twitchy hwoever ive got way more control throw because the orange rx delta mixing is different to the taranis, it gives full moving on elevator or airleron and when you mix the 2 it reduces 1 surface. Rolls are super fast!

I then turned up the gain on the stabilisation and wow it turned into such a smooth flier. the stabilisation is probably making up for cg so ill twe3ak it a bit further forward but what an improvement now the canard is 5 inches back!. No angle on the front canard. it climbs slightly on full power (normal) compared to doing a big wide loop.

This thing is FAST! I knnow this is meant to be for cruising around and FPV but damn this thing can move, im running a 6x5 prop with a 2300kv motor 2200mah 3s battery. Draws 30A at full power on the ground around 260w i think. Its way faster than my flying wing running a 6x4 and 2300kv motor, however its a much much smaller motor 1806 (really needs a 2204)

Such a simple build and flies very well, surprisingly easy to launch once you get the CG right. Pay attention to the motor mounting, if you mount it in the centre of the fuselage you will need down thrust. And dont mount the canard all the way forward just because its easier, get some no nails mounting hooks so you can mount it over the battery tray

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