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Oct 18, 2018, 05:02 AM
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Quote:
Originally Posted by davereap
At 16oz or so, its not overweight at all..
Some of my bigger foamies have been at 20-30oz...560-840 gms and they flew nicely..

But that sort of weight needs some metal geared servos with a bit more power... something 12-15gm size.

For wing stiffening I now use laminating film strips..I use the A3 pouches ..a 150micron pouch has two 75micron sides .. this is strong stuff.. Most often I put 2"strips across the wing , above and below to make a foam sandwich at the thickest part of the wing.. On a KF this is will go on the top of the wing and mirrored below at the step lines.. where needed joints are made, overlapped by about 1".. they dont show up ..
Previously I used pallet strapping glued along the thickest part of the wing, again one strip above and mirrored below..
You can see the strapping on the big V wing above..

https://www.rcgroups.com/forums/show...-reinforcement
the laminating film is used the same as the pallet strapping... but being able to iron it on its a cleaner job..
See the pic for laminating film on the KF layers ... Strapping would have gone along the step lines crossing at the centre and going over as far as the leading edges...
Noted for my next build. I may add kfm2 step later but using depron so ikt shouldn't ad much weight. I've looked into nthew lamenting film defiantly a good idea.

That's what I thought about the servos. 9g servos would probably struggle under load. Will get some ordered.
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Oct 18, 2018, 04:16 PM
Registered User
What sort of stall torque should I be looking for. Seeing 9g servos with same as 12g
Oct 19, 2018, 02:26 AM
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davereap's Avatar
these will be fine... TGY 9018mg
https://hobbyking.com/en_us/turnigyt...10sec-13g.html
These days I am using all tgy servos.. they have been giving very good results for low cost..

hobbyking tgy1440a are in use in most of my indoor models , light weight at 4.4gms with the same performance as other typical 5gm servos (which actually weigh 6-7gms)
Oct 19, 2018, 08:06 AM
Registered User
Quote:
Originally Posted by davereap
these will be fine... TGY 9018mg
https://hobbyking.com/en_us/turnigyt...10sec-13g.html
These days I am using all tgy servos.. they have been giving very good results for low cost..

hobbyking tgy1440a are in use in most of my indoor models , light weight at 4.4gms with the same performance as other typical 5gm servos (which actually weigh 6-7gms)
funily enough have a jumper 25 with 2 hi torque tgy servos in it. The elevator servo went on me luckily i noticed the sluggish behaviour as i was about to take off, checked it and it burnt out on the bench... ive used other tgy servos and they have taken abuse in several models.


OK will be putting electronics together today. Retiring my pizzabox flyer, bored with it and its a bit bashed. taking th 1200kv workhorse motor and accompanying esc (motor soldered directly to it) also the orange rx thats on it. Cant order anything just yet so ill stick my tower pro servos on it for testing.

Dont want to just order servos as want to pick up a few batteries aswell, need 1500 3s for the skipper and im thinking they will do the QV aswell. i can test with 2200mahs, if i maiden ill not do anything stresfull so as to not risk battery falling off or a servo burning out/stipping
Last edited by bazsound; Oct 19, 2018 at 09:43 AM.
Oct 19, 2018, 10:09 AM
flyin' fool
goldguy's Avatar
9018s made by Corona, very good quality.
Oct 19, 2018, 11:40 AM
Registered User
Weights starting to Poole on....

Looks about 560g with motor and speed controller. I put servos poushrods and bastterry to get an idea of how it's going to balance. With a 1500 3s all the way forward it's tail heavy with the current control rod length. The tail servo doesn't have a long enough rod so is at the tail. Move this back and obviously cg moves. But even moving all servos to the cg mark I'm still 4 inches behind the cg mark.


Aup comes to around 850-900g.

To get it to balance without using longer rods to move servos forward I need tl have a 2200may all the way forward and cut a hole is fuse side to have it run through so as much of the battery weight is forward. This adds 50g.

Ok went ahead and put it all together, just needs a slot cut for the battery and velcro to hold it in place. I can see why stronger larger servos are needed, although the hot glue hinges i made (using card with a square cut out as a template, used that to make a nice hinge b y spreading the hotglue in the square) give nice free movement, when you push and pull on the control rod you can feel how much more force is required just to move the much larger surfaces.

Tested power, and even though its got a 10" prop it will climb infact it was pulling strong and i hadnt even went full throtlle. I think the 10" prop produces around 1100g thrust, teh 11 1300g.

So seems almost ready for maiden, just need to make sure the CG is brought forward a bit as its still a few inches rear of the mark. not sure how tail heavy that is. Ive got a 3D plane that is tail heavy but it seems to fly. elevator twitchy even with massive amounts of expo but it harriers really nicely and a ton of elevator authority, it climbs when inverted though making me thing its tail heavy.

From my limited experience it seems tail heavy can be very different depending on the place, seems that planes with plenty of power and lots of control authority tend to fly more than once. where as more scale planes dont have the power and just keep stalling never really get flying.
Last edited by bazsound; Oct 19, 2018 at 01:50 PM.
Oct 20, 2018, 02:36 AM
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davereap's Avatar
sounds to be both on the heavy side.. and tail heavy... not a good combination.

note your scaled up COG is at 11.7" back from the nose... that is essential for flying.
Oct 20, 2018, 06:22 AM
Registered User
Quote:
Originally Posted by davereap
sounds to be both on the heavy side.. and tail heavy... not a good combination.

note your scaled up COG is at 11.7" back from the nose... that is essential for flying.
I'll defiantly make sure that it's on the cg mark before testing. Not so worried about it being slightly tail heavy. I'm actually flying my jumper 25 tail heavy and for giggles removed the 25g nose weight on my raven flying wing. It's tail heavy too.


If maiden goes well I might extend the nose to get the weight forward. Then remove paper on the tail that's usually good and shifting the cg forward. Also carbon fibre control rods and horns could help. This might allow me to shift to a 1500man battery which would save 50g
Oct 20, 2018, 06:56 AM
Registered User
Well... Guess what!

It balances almost spot on. Decided to actually mark the cg transferring the line. I was using a spot on the fuse to guess.

Well I'm about3-4mm aft of the line.


Solo it's ready for maiden. And I'm guessing if I get carbon fibre rod to move servos much further forward I could switch to a smaller battery.


Edit...

Did a power test again. Looks like it will hover about 3/4 throttle. Defiantly will be if it switching to an 11x4
Last edited by bazsound; Oct 20, 2018 at 08:40 AM.
Oct 20, 2018, 10:02 AM
Jim
Be sure to get video!!
Oct 20, 2018, 10:45 AM
Registered User
Quote:
Originally Posted by Jim_W
Be sure to get video!!
Will try and remember to bring my Yi action can.


My one concern is ripping the rudder of landing as the rudder catches the ground. Also realised that I might have to treat the bottom as the grass is now wet..
Oct 20, 2018, 11:55 AM
Jim
Quote:
Originally Posted by bazsound
Will try and remember to bring my Yi action cam.


My one concern is ripping the rudder off landing as the rudder catches the ground. Also realized that I might have to treat the bottom as the grass is now wet..
Water is the paper backed foam boards' nemesis! I made a BluBaby 33" from DTFB and my son landed it in a ditch full of water on its' 3rd flight.

Blue Baby 33 Dollar Tree foamboard (6 min 18 sec)
Oct 21, 2018, 12:41 AM
Registered User
davereap's Avatar
Quote:
Originally Posted by bazsound
Will try and remember to bring my Yi action can.


My one concern is ripping the rudder of landing as the rudder catches the ground. Also realised that I might have to treat the bottom as the grass is now wet..
I often use a bit of CF flat as a skid.. or cable tie.
And where its likely to get wet..take some paper off and replace it with tape covering...or just a bit of tape covering over the paper.
Oct 21, 2018, 05:04 AM
Registered User
Quote:
Originally Posted by davereap
I often use a bit of CF flat as a skid.. or cable tie.
And where its likely to get wet..take some paper off and replace it with tape covering...or just a bit of tape covering over the paper.
Ofcoarase! I've got q couple pieces somewhere.

Yeah I was going to put some coloured packing tape on the bottom and the wing edges also to help orientation.

I might try removing paper and replacing with packing tape to drop the weight a little.

Looks like the maiden won't be working a while. Weather is pretty poor. Rain and high winds....
Last edited by bazsound; Oct 21, 2018 at 05:29 AM.
Oct 23, 2018, 12:08 PM
Registered User
Still waiting on weather to get better. Gusts up to 40MPH today... Gonna be ordering cf rods to redo the control rods. Which will get the servos further forward. Especially the tail servo.


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