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May 25, 2018, 05:23 PM
Gliders ain't drones!
Zenmaniac's Avatar
I don't know the terms "free form air putty" and "free form air spars".

Can you clarify, Gaza or Tim?

Thanks!

-= Dave
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May 25, 2018, 06:07 PM
Rock Breaker
gazasmith's Avatar
Thread OP
Tweety wing is out.
Lee
Come out too good for you
Tim
You jinxed the TBreaker tail feathers a big sink in skin. Some thinking on what happened is needed, beer will help the process.
Zen
foam is 2 part polyurethane foam I used GP330. It goes of very fast and sticks to everything so very hard to pour spread and close a mould. Also a closed mould you need to get everything perfect for success. Pouring in a open mould and letting it free rise with no back pressure is easier. I use a sheet of plastic and a board to create some back pressure. If you have spots not filled just mix a bit more and fill the holes. No need to be accurate no risk to mould just lots of trimming back to parting line.

Free Form Air is a 2part expo putty. Basically epoxy resin with micro balloons already mixed in. Equals parts A and B, need like your making bread then fill the slots I cut for spars. Sets hard glue bond is good and is lighter and easier to mix than a standard micro balloon splonge.

Super happy with wing, almost want a 9am beer to celebrate.
Just a couple of bubbles on LE, I'm suprised how few for a hand layup no vac bag.
Finish is mat as mould not polished to mirror.
Top paint is perfect, bottom has a few fish eyes, lines are sharpe.
Mould alignment is perfect.
LE is thicker than I wanted worst spot maybe 0.5mm. Better clamps and a overflow groove will help that.
TE has a few spots not bonded

Battery about to die best post before I loose it
May 26, 2018, 05:11 AM
608 km/h!
josh18's Avatar
Looks Awesome Gaz! Glad you liked that PU cut off method. I like the bagging in EPS foam method a bit better, it just seems a bit easier and cleaner to do and trim. Strength is about equal i reckon.
May 27, 2018, 06:42 AM
Rock Breaker
gazasmith's Avatar
Thread OP
Josh
I like full core the best. No glue in the middle to make hinge cutting etc harder.

It's funny how the square tail looks good on the Rock Breaker but looks crap on ta Windfire.
Will have to do until fuse is made.
The TBreaker tail looks better.
Was going to use hxt500 servos Until I found out they are way to thick. Tweety wing only 9.8 max thickness. Found some second hand X08 thought I was good until one showed a stripped gear.
Weight looks like will be around 300g may need good breeze.
May 27, 2018, 11:33 AM
pnc
pnc
Registered User
pnc's Avatar
Looking great Gary
May 28, 2018, 05:44 AM
608 km/h!
josh18's Avatar
Looks great Gaz. CG finding will be fun. Have you got a gentle grassy slope to dial it in before a cliff top chuck?
May 30, 2018, 07:56 AM
Rock Breaker
gazasmith's Avatar
Thread OP
Quote:
Originally Posted by josh18
Looks great Gaz. CG finding will be fun. Have you got a gentle grassy slope to dial it in before a cliff top chuck?
I used the old method to work out CG.
Select another plane with similar foil, then just scale CG for smaller cord.
Maybe a bit of guessing added to that as planform is different.
So now Tweety with everything fitted has CG at 21.5mm.

As for gentle slope, no I got about 15mtrs of grass then cliff and rocks.
It's simple throw it and make choice fast wether to go up and fly or drive it into the grass and reset.
Twin elevator sticks helps can run right stick at low rate and left stick at high rates. If tail heavy low rates to fly home or nose heavy pull both sticks to keep nose up carefull not to stall.

The other big question is how much wind do I need. 294g for a small plane most likely maiden will be in minimum wind strength for wing loading..

Keel moulds should turn up tomorrow so got a week or 2 flat out on my boat.

Maybe find a few minutes if wind gods are good for a maiden
May 30, 2018, 08:56 AM
Certifiable User
killercando's Avatar
Tweety looks really nice, even with the square tail. Hope you get some air soon

Lee
May 30, 2018, 11:52 AM
A dream will find you
StevenSeim's Avatar

Fly it with the stab...


Put the T-Breaker stab on the model Gary, and use it.

Angle the fin such that the stab and wing are planar.

It will rock. A slope 'Genesis II'
May 31, 2018, 02:43 AM
608 km/h!
josh18's Avatar
Hey Gaz what is a t- breaker? I didn't like the way my lothian plank flew with a plank foil an a tail. It was OK but not great.
May 31, 2018, 07:59 AM
Rock Breaker
gazasmith's Avatar
Thread OP
Quote:
Originally Posted by josh18
Hey Gaz what is a t- breaker? I didn't like the way my lothian plank flew with a plank foil an a tail. It was OK but not great.
Only special people get a TBreaker.
https://www.rcgroups.com/forums/show...4#post39733589

In the Rock Breaker thread there is info.

First thing I learnt with TBreaker was don't use snap flaps. A plank foil with the reflex works different from a standard foil. I think it has a different air flow on the control,surfaces. This flow will make snap flaps over power the elevator in tail. Better to program ailerons to still be elevators at a lower rate. The other change I made was to increase elevator size from max 25% for pw51 tail to 30%, the small bit of extra power gave it a good snappy elevator at full rates. Other than that just make sure wings and tail are aligned.

Lee and Steven just got there's might get some DS reports soon.
May 31, 2018, 12:51 PM
A dream will find you
StevenSeim's Avatar

Right you are...


Yes. Flow over a reflexed airfoil/surface greatly affects the pitching moment. Keeping control surface movement to a minimum is an aid. A small/vestigial stab can help take that pitching load off the wing.

Rock Breaker is big fun, but I'm looking forward to flying T-Breaker. That will be a blast.
Jun 02, 2018, 05:45 AM
Rock Breaker
gazasmith's Avatar
Thread OP
Quote:
Originally Posted by StevenSeim
Yes. Flow over a reflexed airfoil/surface greatly affects the pitching moment. Keeping control surface movement to a minimum is an aid. A small/vestigial stab can help take that pitching load off the wing.

Rock Breaker is big fun, but I'm looking forward to flying T-Breaker. That will be a blast.
Hehe Steven I think there both Great.

Wind gods today gay t he correct direction but not enough breeze so the Tweety sat on the bench all today teasing me.

someone said I build fast
Keel build is moving fast.
Mdf moulds turned up Thursday.
Sanded them and bogged a few spits Thursday night.
My mate sanded a bit more and pianted them with high build undercoat Friday morning.
Temps were low so Friday night I turned the heater on something I never normally donliving in the tropics.
Was good got paint to go off enough that Saturday morning I could start sanding.
Have been sanding all day my body is only still moving because of the drugs I'm taking.
Mould release sealer coats are on, another 30mins and I'll start release coats.
Most of the clothe is cut, a few fill bits to go then preheat moulds resin clothe etc for layup.
Coffee coffee I'll need a few cups in the morning to get brain working.
Time out, take 5, firetruck what have i forgotten.
Read resin specs again, check pit time thin film time.
Plan vac pressure timing.
Think think think what have I missed.
11kg new calculated weight compared to 22-23kg old keel is my layup strong enough.
I think time is almost up, now to read release agent specs again and start applying

Oops drugs first refill cup
Jun 02, 2018, 06:27 AM
It's time for me to fly
JimZinVT's Avatar
What kind of boat Gaz?
Jun 02, 2018, 09:24 PM
Rock Breaker
gazasmith's Avatar
Thread OP
Quote:
Originally Posted by JimZinVT
What kind of boat Gaz?
8mtr sports boat
Go full retard (1 min 14 sec)

And this one without music I like better you can hear the chat on board. Top speed 23knts
Airle beach race to the cones [RPMC] (3 min 46 sec)

And this one going around island Cape Cones we call it. Brand new mainsail got half its life used up in 1 race.
Airle beach cape cones [RPMC] (9 min 0 sec)


Sunday lunch and skins are bagged.
1924g of carbon 1100g resin looking good.

Now hopefully breeze swings and holds some strength so I can fly soon.


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