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Mar 28, 2021, 09:25 PM
Registered User
Thread OP
Discussion

Facet delta-wing series


Initial version is a delta configuration glider, as a build and dynamics trial.

The Facet part is fuselage cross-section.
Hexagonal/octagonal mixed as required.

A larger RC version is planned. (560mm span)
Propulsion is to be pusher prop.
-----------------------------------------------------------------------------------------------
If you wish to comment, please be supportive.

I do not wish to be forced to defend my decisions, as it can get out of hand, and peoples feelings can be hurt.
(from previous experience).
-----------------------------------------------------------------------------------------------

1) Stage 1 glider 240mm span well under way.
wing frame completed.
Ready for covering.

2) Short twin boom tail section added, elevons move the same way as the wing elevons.
-prototype for 2x scale rc model.

3) Rubberised CA glue seems to be good for balsa.-similar consistency to balsa glue-
A bit harder when set.

Doesn't set back down the "spout-all air excluded-"toothpaste"-style tube.
Dribble and build-up on spout still a problem. can be removed with clippers, but
original spout gets destroyed.

4) Cut-down needle-type hinges used on outer elevons, -tend to seize up with CA glue.
I may use a different glue and be a bit more careful.
The glider only need rear tail elevons to work, anyway.
The wing elevons are of use on the scaled-up model to improve roll authority.

5) The next stage design is changed to a more v-wing layout. similar leading edge sweep angle, slightly more span, Increased by 80mm.
I think this layout improves rear prop efficiency.

The new tail planes are centered on the vertically offset prop.
Fitting servos in the wings and running pushrods up the tail boom/fins is a bit tricky.
The fin supports need to be clear of the servos.

Maximum thickness of fins may be 15mm.

A top bellcrank is needed for the vertical rudders.-top and bottom-linked.

I need to work out a good prop clearance from elevator ands rudder "planes." -about 1 inch at the rear?

The center fin is just a frame looped over to support the skinny rudder plane/rod/fin.

That can have 2 inches front prop clearance-in the middle, anyway.
I have angled the motor a bit. so the axis passes through the nose, but slightly above the COG.

Also, extending the wing back past the motor moves the required COG back a bit.

I am aiming at 10% of the mean chord for now.

Possibly I can try up to 15 % later?

I have sloped the rear elevator plane a little, but it will need more down-trim when flying.

-this is similar to the case with a normal tailplane, elevator which is usually trimmed slightly up, then reduces with speed.

Using 1/16 sheet and square 1/16" stringers also is not practical.

I didn't realise it was so fragile! Vast numbers of part wing stringer replacements.

The basic material is too soft a grade, and not cut square.
So much for ordering it as precut stick bundles!

It a while since I built any balsa and tissue models!

1/16 and 1/32 can be used for skin and panelling, and some smaller supporting pieces.
1/8" for ribs, 1/8" sq stringers, 1/4" sq for spars.

I would like to get some finishing epoxy resin for balsa laminates.
The smaller bottles are still quite expensive.
$30 nz for 325 ml, $45 for 650ml, $65 for 1.2 L. Undecided as yet.

Laminate would be good for 1/8" ribs, as I can do internal cutouts more easily.
Maybe drill and cut to shape with dremmel milling cutter?

A reasonably hard balsa should do the spars- not full soft!
I can get some spruce or birch spars if the 1/4 looks a little soft.
I will also do the 640 span model full 1/32 balsa skin.

It is a bit tricky getting servos, pushrods, and fins installed after film covering.
The fuselage is only 2 inch on the larger model, but I can extend equipment bay into the thick wings- 40mm.

The outer servo bays will be underneath.
I need to decide on a hatch fastening system.

On on side, 2 servos will have the arms facing each other, so the bay will be about 80x30, 14mm deep except where the arms are.

To drive inner and outer elevons from the same servo, I think a fancy link system will be needed.
Angularity is not right to drive both elevons off the same servo arm.
The elevon horn on the prop center plane will be underneath.
Also line of access is not correct for both.


I will look at it closer once I have built some of the larger wing.

Also the angularity of the top elevator horns may be a problem.

A direction-changing pivot arm may be needed.

The rudder pieces of the "cross" layout can be driven from the bottom.
It needs a steady bar across there, anyway, as the non-moving rudder "plane" will be quite narrow.

Here is a smaller plan of the new layout.
I will post pictures once the small glider is finished.

It will be quite hefty for .425 sq ft- 150g? 5.25 oz.- looking like that, anyway.

It doesn't have to be a good chuck-glider, though.

It is mainly to determine the anhedral effect of the flat bottom, sloped top wing,
and whether it wants to fly right side up.

The objectives of the additional tail surfaces is to experiment with thrust vectoring.
Some automation may be required to forestall sudden nosedives.

The general layout can be taken as fairly fixed, for now.

A very high thrust to weight ratio is planned, (2:1) so skid takeoff on grass should be possible.

I have estimated that 8 degrees attack angle should be enough to get off the ground at 15 mph,
7 oz/sq ft.
I know that full size aircraft use more, and that full takeoff lift is not generated until 40-45 degrees, but we shall see.

If it doesn't take off straight away, I will have learned something.

The bigger aircraft have higher wing loading, and need to use more of their lift capacity, to keep take-off speeds down.

I think they ground-rotate around the rear set of wheels.

I can incorporate a similar arrangement if needed.
Last edited by Owen_bern; Mar 28, 2021 at 10:22 PM.
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Mar 29, 2021, 11:25 AM
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Thin-Winged Deltas


Thin-wing deltas are so common because folks have discovered they have far more stability, greatly increased maneuverability and easier, better handling needing less power.


https://www.google.com/search?q=Delt...ih=515&dpr=1.5


Typical Thin-Winged Delta
Last edited by xlcrlee; Apr 01, 2021 at 07:34 AM.
Mar 30, 2021, 01:40 AM
Registered User
Thread OP
1) Thick wings are commonly used on flying wings- this just has a bit more sweep angle.
2) I want more in-wing space for equipment:
- outboard-mounted servos for the twin tailbooms.
-middle equipment bay will extend to the second rib each side.
44mm is a bit narrow for my proposed gear.

3) It is not a "true" delta, as the center section extends some way beyond the trailing edge,
and the prop, and it incudes twin booms.

The proposed larger version is even less delta.

There are some design inefficiencies because the layout is partly based on looks.

If I wanted better efficiency, I would have a front prop, and a standard taildragger undercarriage
That also has good blow-over of the normal control surfaces.

I am not opposed to thin deltas.

I just thought I didn't need one in this case.
-----------------------------------------------------------------------------------------------

On another matter,
the rubberised CA needs a smaller tube or spare nozzles.
The existing nozzle gets destroyed easily when I clip off dribble buildup.
I will look for smaller tubes. 28.5g is too big in this format.

The wing is looking nice in its red film covering.
It reminds me of an upturned bread plate or shallow dish.??
A shape like that would probably work as well!
Mar 30, 2021, 07:35 AM
Registered User
With experience one discovers that efficiency directly relates to stability, maneuverability, ease of control and crash-survivability (strength/wt. and power/wt.) .... nice to have, whether one "needs" it or not, eh?

Think of that bloated pig of an overloaded container ship which got stuck in the Suez Canal; bet their insurance company wishes it had been lighter, more maneuverable and controllable (can't always count on a high-tide Super Full Moon to help out)


Regardless, Best of Luck with the Fat Facet, Owen....

Happy Landings

Lee
Last edited by xlcrlee; Mar 30, 2021 at 03:55 PM.
Mar 30, 2021, 08:09 PM
Registered User
Thread OP
Getting back to standard balsa glue.
I am using this more now.
Just reordered, along with more balsa.

Not too bad if you pre-coat all joints, then re-glue with pins.
Doesn't take that long to set- a couple of minutes.

Good if you are sick of trying to sand CA glue, clip it off with clippers,
or getting it on your fingers.- quick dash to the cold water tap. This gets hot!

I keep plenty of acetone on hand, as well as release gel.
I usually need to unstick myself about once a day.

Blocked nozzles have been a problem.
The squeeze tube tends to block less, and is easier to get going again.

I reordered more toughened CA as well.
I can only get the 1 oz tube.
It is still quite hard to sand, but a little softer than normal CA.

I see you can get "foam safe" CA, which has less smell. - the standard stuff can make your eyes water!

The tube with the busted nozzle now has the pointy bit of a drawing compass
as a stopper.-you can get it out again with a pair of pliers.
-------------------------------------------
Basswood as spars? 1/8" x 1/4". (for the 560mm span version.)
Angle-lap with a short straight bit in the middle, toughened CA glue?
This can go across the bottom equipment bay as well.

Does 1/8 x 1/4 also need a cap strip?
This acts as a doubler at joins.
A step at the edge would be a problem.
Maybe a narrow balsa cap on top the full length?
Alternately, a horizontal reinforcing plate can be glued to the inside of the "V" area.

The upper rib can be an arc, and a strut to space out the bottom spar.
- this is the rib next to the fuselage.

Maybe the arc can be laminate/ply as well?
It is pretty well stabilised by front and rear location, plus the spars.

I want to cut out the front center of the wing .
Maybe a "spar box", short spars or stays into the wing structure, to pick up the 1/4x 1/2 leading edge?
If a diaphragm spar is extended out, it intersects the leading edge.
Laminate or thin ply?

The facet fuselage is coming along nicely.
I can't use the extensive sheet inner formers on the next model, though.
"keel" pieces and hollow formers may be better?
This is easier at the larger scale.

Idea for a yet larger version:

Twin front props, about 1m span?
This sort of resurrects the previous "Wing" twin prop version.

The motors would need quite long pylons with this sweep angle.

I can then eliminate the "double-tail" feature.

if the single prop version flies well, I wouldn't bother, unless it gets accidently destroyed.
(Likely?)
Last edited by Owen_bern; Mar 30, 2021 at 08:19 PM.
Mar 30, 2021, 11:19 PM
Registered User
Thread OP
Just a thought on bottom spars and the wide equipment bay.

Bottom spars can just go straight across for most of the span.
It is fairly flat.
I will draw that up.
The main top spar can still follow the high point of the wing section.
Mar 31, 2021, 05:13 AM
Registered User
What you are working on would be OK for an already advanced and experienced FLYING-model builder and RC pilot. You are obviously aware that you WILL smash it (several times, if you are lucky enough to even get past the 1st crash) trying to get it and yourself sorted out. The result will be a pile of sticks and useless torn covering nearly impossible to re-assemble.

If you simply love amusing yourself with complex 500-pc cardboard picture puzzles you might enjoy the challenge ... but it will weigh a LOT more and fly even worse than before the crash/es.

However, building it instead from THIN facet sheets of Depron (you can measure them by first making a dummy out of cardboard pieces for templates) plus a few balsa spars, hardwood L.E., etc.,, will allow almost INSTANT after-crash re-assembly using THE all-time best product for this:



https://www.gordonharris.co.nz/produ...rene-glue-50ml
Last edited by xlcrlee; Apr 01, 2021 at 12:39 PM.
Apr 01, 2021, 02:05 AM
Registered User
Thread OP
Xlcrlee is on my ignore list at present.

If you want to be sensible, get someone else to post your truce message.

"Flamers" from previous posts are also on ignore, for now.
----------------------------------------------------------------------------------------------------------

On other matters, I am getting more inclined towards the twin prop puller, at maybe a larger scale .
This general layout seems looks easier to build than my previous flying wing, with less, and simpler, fuselage structure.

I would like 15 oz/sq ft or lower.
This seems to be a consensus value for most non-flaps models.
at 800g or 28 oz launch weight, (is this reasonable?)

The facet fuselage section looks OK, so I will keep this for now.

Wing area = 1.83 sq
= 263 sq ins = 16.2 x 16.2


Scaled, smallest drawing = 140mm = 5.5 ins.
av chord = 68mm = 2.7 ins.
base area = 14.85 sq ins,
area ratio = 17.7
linear ratio = 4.2
5.5 x 4.2 = 23.1 span.
2.7 x 4.2 = 11.34
total area = 261 sq ins.--This checks out.

Increase the linear ratio to x 6,
gives span = 33 ins
av chord = 16.2 ins.
new area = 534. 6 sq ins
= 3.7 sq ft.
wing loading = 7.6 oz/ sq ft
I will check this on e-calc.

This layout restores possible VTOL capability.

I will keep the VTOL-style tail protrusions with twin fins,
but make them proportionally taller.

I could use a single 3 inch front wheel in taildragger mode, and keep metal tailskids.

I can eliminate some of the extra complication of the pusher proposal.

Battery = 4000 to 5500 mAh.
Prop centerlines about 70% out along the wing.

This allows them to be set back a bit, but still ahead of the trim COG.

The facet fuselage sections look OK, so I will keep this layout for now.

At the moment, on the small glider, the front section is semi-triangular 4-sided, with rounded edges.
The flat panels are curved in one plane.
Photos to follow when I have tidied and painted it a bit.

I suppose my inclinations tend towards design and build, rather than flying.

When I can afford batteries, I will finish off the PNP plane and give it a go.
I need to practice more on the simulators, first.

-Unexpected vet bills at the moment, on top of the plumber bill.

One of my cat got bitten by a roaming dog at night, but managed to get away.-
Probably not a Pit-Bull.- cats generally don't escape them!
- the dogs get pretty scratched up, though.
We have plenty of pit-bull crosses around here.

Random children generally don't get attacked,
but there are the odd cases of attacks while the owner was showing the dogs to strangers.

They will try to fight dogs on leads, though, and they are hard to discourage.

My cousin was a Postie, and she got attacked by an unusual asian hunting dog.
The person looking after it was careless with leaving the gate open.
The dog was euthed by court order.

-The cats get let out at night around here.(not illegal)-
Unfortunately, some dog owners let their dogs roam at night, too (Illegal!)

In some places in Australia they make cats stay in at night because they have a lot of local protected small creatures.
Probably Nocturnal?
You see the odd fantail around here, but most creatures are imported pests or other exotics,
or doing well despite predation.

The Department of Conservation doesn't like cats in native forests,
but generally the birds nest in spiky tress, and are more vulnerable to
rats, weasels, and stoats.
Cats don't really hunt in trees a lot.

In some scattered areas there are actually small ground nesting native species.-
They don't last long with cats around.



There are shore-nesting birds in isolated colonies along the coast-sandy beaches.
-cats generally don't get that far, and most birds are big enough to discourage cats.

There have been problems with people taking dogs into those areas- coastal recreational surf fishers?
if you stay out of the dunes, the birds are generally OK.



I got the fancy oil and filter for the car.
The price of synthetic 5W-30 seems to be less, nowdays.-
I have been using 10W-30 semi-synthetic in the past.

Maybe this will reduce the "crud" buildup in the inlet manifold, too.

-loose carbon crystals-quite hard and sharp-like coarse sand.

- Possibly due to oil from crankcase vapour and exhaust gas recirculation getting a bit hot.
The varnish and gum in the oil helps the crystals grow quite large.

I had to replace the "tumble" valves in the manifold when I got the car.- at 60,000 kms.
-second-hand.

The tumble valves have plastic bearings.

It hasn't been so bad in the last 60,000 kms, though. (37,500 mi)
- not so much slow city traffic running.
Last edited by Owen_bern; Apr 01, 2021 at 05:44 AM. Reason: image
Apr 01, 2021, 05:14 AM
Registered User

The Ground is a HARD Teacher


Quote:
Originally Posted by Owen_bern
Xlcrlee is on my ignore list at present.

If you want to be sensible, get someone else to post your truce message.
Happy Easter, Owen. "Truce"?

It seems that the only battle going on is between you, yourself and the realities of RC modeling and flying with which we all have to deal. So far, everyone responding to your almost FIFTY! (50) threads you have started and usually closed in the last few months ....

........... has been trying to help you

When you finally ever get to fly an RC plane you might discover the reasons behind all the help you have refused; in case you are unaware a main purpose of RCG is for members to help each other


As shocking as it may appear, it is always possible to learn, but we will have to let Gravity take over from here



references
https://www.rcgroups.com/forums/show...9#post46785015
https://www.rcgroups.com/forums/show...0#post46786129
https://www.rcgroups.com/forums/show...0#post46785825
https://www.rcgroups.com/forums/show...0#post46785617
https://www.rcgroups.com/forums/show...0#post46786419
https://www.rcgroups.com/forums/show...r-delta/page10
Last edited by xlcrlee; Apr 01, 2021 at 07:37 AM.
Apr 01, 2021, 06:37 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Quote:
Originally Posted by Owen_bern
Xlcrlee is on my ignore list at present.
If you want to be sensible, get someone else to post your truce message.
"Flamers" from previous posts are also on ignore, for now. ...
Quote:
Originally Posted by xlcrlee
Happy Easter, Owen. "Truce"?
It seems that the only battle going on is between you, yourself and the realities of RC modeling and flying with which we all have to deal. So far, everyone responding to your almost FIFTY! (50) threads you have started and usually closed in the last few months ....

........... has been trying to help you

When you finally ever get to fly an RC plane you might discover the reasons behind all the help you have refused; in case you are unaware a main purpose of RCG is for members to help each other.

As shocking as it may appear, it is always possible to learn, but we will have to let Gravity take over from here


References
www.rcgroups.com/forums/showthread.php?3850275-Facet-style-pusher-delta/page9#post46785015
www.rcgroups.com/forums/showthread.php?3850275-Facet-style-pusher-delta/page10#post46786129
www.rcgroups.com/forums/showthread.php?3850275-Facet-style-pusher-delta/page10#post46785825
www.rcgroups.com/forums/showthread.php?3850275-Facet-style-pusher-delta/page10#post46785617
www.rcgroups.com/forums/showthread.php?3850275-Facet-style-pusher-delta/page10#post46786419
www.rcgroups.com/forums/showthread.php?3850275-Facet-style-pusher-delta/page10
Have you noticed Owen, that Lee is the only one who tried to help you in this thread? Despite 600+ views.

I think Lee's criticism is valid. He, and others as well, gave you a lot of his/their time. Putting Lee publicly on ignore was unnecissary, you could have done that via a personal message.


Vriendelijke groeten en wees voorzichtig, Ron
• Without a watt-meter you're in the dark ... until something starts to glow •
E-flight calculatorswatt-metersdiy motor tips&tricksCumulus MFC
Last edited by Ron van Sommeren; Apr 01, 2021 at 07:20 AM.
Apr 01, 2021, 03:21 PM
Registered User
Thread OP
I am not familiar with personal messages on this site. - I will look at that.

Some posts by certain people were looking rather flamey.
They did not contain useful
or interesting information, and seem to attempt to be annoying.

Some prior advice was widely divergent from my line of thought at the time.

I need to get there at my own speed, maybe with a little prompting.

I do not need any more suggestions on general model concept, thanks.

I think I am getting to a practical layout.
Note the proportionately thinner section depth in the last drawing.

60mm should be enough if I need internal space for control gear.
This tapers to about 21mm (0.8") at the tip (35/100)
This seems about right -I was thinking 12-19 mm in 210mm, or around 8%
21mm is 10%


Practicing on a smaller scale model has been helpful.

Detail design and construction tips would be good.

Those motor pylons look a bit spindly, but they are 33mm diameter.

I need to boost elevon width a bit.
I have trimmed that back too much.

Pushrod approach angle to the control surfaces is a problem.

-I sort of created the problem in designing vertical fins for appearance.

I will look at the trimmable plastic core flexi-pushrods a bit more, including end fittings.
Do I need screw-on split trunnions at both ends?

The vertical fins with rear support extensions need "prettying" up.
I am not sure whether they need to be aligned with the propellers.


The ardupilot uses bi-copter motor control for tailsitter flight, but I don't know about
normal flight yaw balancing. - widely spaced props may need this.

The "delta" shape looks better with the props spaced out and set back a bit.
They can be brought back in slightly, if it is a problem.
Apr 03, 2021, 04:51 AM
Registered User
Thread OP
back to accounting for weight.
basic airframe at 240mm span is 50g.
assume frame weight is equivalent linear scale squared.
x3 scale = 450g.
I can narrow this down a bit with the new balsa-film setup.
A lot of the frame is volume-based, so cube relation.
ie double thickness, 4x weight per unit length, 3x linear dimension for spars and stringers,
12x ratio.
Ribs: double thickness , square dimensions, but lightening holes say 30%?
= 2 x 9 x 0.6 = 10.8 ratio.
Skin- from film at 50 g/sq mt to 1/32 balsa at 100g/ sq m.
New area 534 sq ins
total surface = x 2.3 = 1228
1550 sq in per sq mt.
area skin sq mt = 0.8.
skin increases from 40 g to 80 g, so not huge.
Coatings at 0.05mm, 70 gsm.
3 coats needed: grain sealer, undercoat, topcoat. = 168g extra.
It is likely that airframe will be at least 500g,
battery = 350g
motors + wires = 100g
receiver + servos (4) + flight controller + camera/transmitter- likely 70g.
pushrods, hinges, other wire, horns, fittings-50g??
At present, looking at 1040g, 1900g static thrust.
How does this compare with other planes at 1m span?
Launch weight of the 1400mm foamy zero was?
I will check.
zero = 1880g: retracts, flaps, larger span.
T28 = 1080g: fixed undercart, no flaps, similar span, less engines and electronics, 4000mAh bat.
Last edited by Owen_bern; Apr 03, 2021 at 05:00 AM.
Apr 03, 2021, 05:28 AM
Registered User
Thread OP
Quote:
Originally Posted by xlcrlee
Happy Easter, Owen. "Truce"?

It seems that the only battle going on is between you, yourself and the realities of RC modeling and flying with which we all have to deal. So far, everyone responding to your almost FIFTY! (50) threads you have started and usually closed in the last few months ....

........... has been trying to help you


When you finally ever get to fly an RC plane you might discover the reasons behind all the help you have refused; in case you are unaware a main purpose of RCG is for members to help each other


As shocking as it may appear, it is always possible to learn, but we will have to let Gravity take over from here

I have removed the "ignore", from some people, but I can rebut.


Many threads were specialist and not being used for other discussions.
I don't want to leave open and subscribed threads I am not using, and no-one else is using for other purposes.

If the topic was more specialized, I opened specialized threads.-I was asking questions in different areas, and
they would be obliterated in other threads, plus I think the audience is different.

I would count this as imaginative use of the site???

Quite a few started design projects lost my interest, so I closed them.
I have sort of turned full circle on concept, but with better ideas and techniques.

I have actually taken some advice and used it.

I have a cheap, ready built plane which is somewhat learner-grade. I just need to finish it.

Just because I may be an unusual user of this forum, and want to work on several things at once, doesn't make me a "Bad"
aeromodeller!



I don't know what these are: presumably advice I have ignored, or argued against?
I am not bothering to re-read them.
That is just rehashing the past, which I try to avoid doing.

Some people seem to have developed a "Flamey" attitude, or regard me as some sort of "enemy of the people"
who must be combatted and beaten.

-This sounds like a combination of wounded pride, "know better" attitude not scientifically based,
and "Gatekeeper" hostile action similar to the "Nerd" and "Geek" groups I have encountered.

Not everyone will agree with you, even if you "know" you are right, or have had more experience.

I may have made some speculative and unsupported propositions in the past, but I do change
my ideas if I am presented with reasonable precedent, or by my discovery of general information undermining my position.
Apr 03, 2021, 05:55 AM
Registered User
Thread OP
Quote:
Originally Posted by xlcrlee
What you are working on would be OK for an already advanced and experienced FLYING-model builder and RC pilot. You are obviously aware that you WILL smash it (several times, if you are lucky enough to even get past the 1st crash) trying to get it and yourself sorted out. The result will be a pile of sticks and useless torn covering nearly impossible to re-assemble.

If you simply love amusing yourself with complex 500-pc cardboard picture puzzles you might enjoy the challenge ... but it will weigh a LOT more and fly even worse than before the crash/es.

However, building it instead from THIN facet sheets of Depron (you can measure them by first making a dummy out of cardboard pieces for templates) plus a few balsa spars, hardwood L.E., etc.,, will allow almost INSTANT after-crash re-assembly using THE all-time best product for this:



https://www.gordonharris.co.nz/produ...rene-glue-50ml
I have given up on "depron" as the only supplier won't answer my emails.
Either they are incapable of doing so-as per some on-line shops with email enquiries-
or they can't be bothered with shipping the stuff in small quantities, or cutting it for practical shipment, or with telling me that.

I am not using the foamboard.- it has quite heavy card surfaces, is not waterproof and doesn't look that that easy to work with.
The local supplier also only has 5mm thickness.

I am now back to balsa, which I have collected tons of.

It is way slower to work with than card, though.-2 weeks build vs 2 days?- I have put a few hours into the small-scale glider.

Hot-melt glue seems to be favoured by foam builders and repairers.
I am looking at a 12V dc hot-melt gun to go with my foam plane.

I also have some instant spray contact adhesive which may come in handy.-
at least for making a build pinboard.
It tends to go everywhere (you don't want it to) for general use, though.

Re: sorting myself out: the foam plane is for that, plus I will join a club.

The sticks and stuff plane is a side project, and needs more expensive radio gear.
It won't be flying in the larger version for another 6 months.

I may get some setup assistance and an experienced RC pilot for its maiden flight.
I am sure some of the local club members will help.
I just need to avoid pissing them off, and follow flying directives given.

I am wondering if the acrylic varnish or the balsa sanding sealer, are compatible with
standard balsa glue. They all seem to clean up well in acetone.
bare balsa seems to benefit from a thin smear of balsa glue, both sides, without significant bowing.
I wonder if it will stick to acrylic varnish... or non-shrink dope, or weak dope.
They seem rather expensive at 24-29 NZD for 250g.
350g of finishing epoxy is cheaper!
I have a litre of varnish, which was about $60, I think??- I will check.
<edit>
I cannot find it online again. I will check the can I have.
Last edited by Owen_bern; Apr 03, 2021 at 06:11 AM.
Apr 03, 2021, 08:32 AM
Registered User
To avoid wasted time and energy, as a practical designer/inventor, before I "re-invent the wheel" I research and look around -- including in Nature -- to see what exists or has existed for the same purpose, goal or use.

You are smart: BALSA is and has been a great flying model material. It is also very easy to repair with normal hobby-viscosity CA (and then Titebond, as below ... but only if really needed, as usually the CA alone is perfect for repairs).

First and foremost is to select the proper density, grain and grade for each desired function in the model, usually requiring going to a large "craft" store (architects, etc., can use balsa for their models, for ex.) or hobby store (or distributor). If you are unaware there is a lot of info re: density, grain and grade online and in the RCG Free Flight Forum: https://www.rcgroups.com/free-flight-64/ (please first use the Search function: "Search this Forum") BEFORE starting a new thread.

BASICS:
https://www.modelaviation.com/balsa

Here is the tried & true decades-old "new" method to build LIGHT, STRONG and very QUICK with balsa:

1. Use micro drops of normal hobby-viscosity CA to lightly tack two pieces together, whether spars, formers, stringers, leading and trailing edges, ribs, or spots on one edge of a covering outer sheet section (one of your "facets")

NOTE: this is just to lightly hold the pieces in contact together ... INSTEAD of pins`(but not instead of a building board ... which in this case can be the FLATTEST material around: GLASS from a window pane or even especially a large dressing mirror! > this can even be vertical to start with the CA, using adhesive tape).

2. Then simply put a glob of Aliphatic Resin "glue" on the joint! It has the special ability to seep into the cellular tubes comprising the balsa wood and therefore internally strengthens the joint by distributing stress, avoiding stress risers! It is often called Carpenter's Glue and is also used by professional wooden instrument builders and repairers! I have used it many times to repair cracks on the face of an acoustic guitar, having learned this from top-class guitar builders. Aliphatic Resin "glue" is a much improved version of old-fashioned white glue. It is available in most quality DIY outlets. Titebond brand is commonly sold in the model hobby market.

https://en.wikipedia.org/wiki/Wood_glue#Aliphatic_resin
Quote:
Aliphatic resin

Aliphatic resin, also known as "carpenter's glue" and "yellow glue," is a synthetic adhesive (in this case, an aliphatic compound) with a light yellow color and creamy texture used most frequently to bond together pieces of wood. Compared to other adhesives, it has low odor and flammability, moderate bonding strength, and moderate moisture resistance. It is more heat- and water-resistant than polyvinyl acetate "white" glues, has a heavier consistency that results in fewer drips, and sets at temperatures above 50 F (10 C) and up to 110 F (43 C), though it is considered unsuitable for outdoor use. Its faster set-time than white glues can make its use on complex projects difficult. It cures in approximately 24 hours, and results in a glue line that is either translucent, pale tan, or amber. Before it cures, it can be cleaned up with tap water (like white glue). Unlike white glue, its heat resistance and hardness when cured means it can be sanded, though it will not absorb wood stains applied on top of it. Excess resin must be sanded off or otherwise removed before staining.[12] It has less tendency to "creep" (slide during clamping) than white glue.[13] Aliphatic resin has a similar use profile and relative ultimate strength as PVA. The two glues differ in grip characteristics before initial set, with PVAs exhibiting more slip during assembly and yellow glue having more initial grip. Brands include Titebond and Lepage.
Google: "Titebond aliphatic resin glue new zealand"
https://www.google.com/search?q=Tite...hrome&ie=UTF-8

Last edited by xlcrlee; Apr 03, 2021 at 09:24 AM.


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