[Kedumba]

Hi All,
The horrible conditions on saturday got me to thinking that it would be nice to have something to work on when I'm unable to fly. It just so happens that the September issue of RCM&E Magazine had a set of free plans for a Luton Minor electric airplane. After looking at the plans I thought I'll have a go at this so off to Bunnings to grab some balsa.

I'm gonna try to turn this:    

into this:    
and show some pics along the way.

First off, cutting the wing ribs and tips, then transferring the plan to the wing skin, then the initial gluing of the wing framework. Waiting for it all to dry before going to the next step.

[smuzz]

Good on yer Mick! Will be watching with interest

[Kedumba]

Hi All,
I need a couple of things for my Luton build but I'm having some troubles.

First off, The Plans/Article specify a AXi 2208/34 motor with an 18 amp ESC. Initial searching show that this motor is terribly expensive. Decided to check out the Hobbyking website and was overwhelmed with the number of choices of motors and I have no idea which would be a good substitue or even how to work out what a good substitue would be.

What it needs (according to the article) is to supply at least 100 watts of power, maybe a little more, run on a 3s pack, swing a 9" prop ( 9 x ?? no information) and cost a whole lot less than the AXi. Could someone reccomend a motor/ESC combo that would do the job.

There are 2 other things I'm not real sure about. One is that the plans specify some Lite Ply to reinforce a couple of spots in the wing. I need a 12" x 12" 1.5mm Liteply sheet. Can anyone advise on somewhere local that i can get some of this or if I can substitue something else for it.

The last thing is that I need a spar for the main wing. It needs to be 3mm x 9mm x 914mm. The instructions say I need spruce but I can't seem to find any locally. What would I be able to substitute for this? I was thinking maybe some pine but don't know enough about it to be sure.

Thanks in advance for the advice

[~KevJ~]

I'm just posting this here to help me manage screens as I'm working from iPhone, this is the spec of your recommended axi for reference,

You will be surprised by the very high power delivered by these small and very robust, but light weight (45g with power cables) brushless motors with rotating case suitable for all models of Slow and Park Fly size weight up to 500 g. The hardened steel 3,17mm diameter shaft is supported by two large ball bearings which ensure very good mechanical reliability with front or radial mounting. As a result of using the latest ferromagnetic materials the AXI GOLD 22xx/xx LINE motors offer extremely high efficiency and high load capability for their weight. AXI GOLD LINE with the high quality of manufacturing, reliability and performance are the best outrunners available in the market. A feature of the AXI design is provision for radial mounting (see picture). The optional radial mount set includes: mounting plate, propeller adapter, securing collar, and screws.
Specification
No. of cells 8 - 10
2 - 3 Li-Poly
RPM/V 1100 RMP/V
Max. efficiency 81%
Max. efficiency current 4 - 7 A (>74%)
No load current / 10 V 0,35 A
Current capacity 8 A/60 s
Internal Resistance 260 mohm
Dimensions (diameter. x lenght) 27,7x26 mm
Shaft diameter 3,17 mm
Weight with cables 45 g

---

Ok so I guess the first things I look at is that it's an outrunner, it's an 1100 kv motor , suits 2-3s lipo, weighs 45g ,And suited for planes up to 500g auw.. It's at this point that I realize I'm talking about things producing what most of my motors are farting so I give up the search and hand you over to a lightweight expert like drew or k barnes jokes... I'll have a look at HK but hopefully the post will be good reference for others

[~KevJ~]

Ok so I guess the first things I look at is that it's an outrunner, it's an 1100 kv motor , suits 2-3s lipo, weighs 45g ,And suited for planes up to 500g auw.. It's at this point that I realize I'm talking about things producing what most of my motors are farting so I give up the search and hand you over to a lightweight expert like drew or k barnes jokes... I'll have a look at HK but hopefully the post will be good reference for others

---

PRODUCT ID: TR2209/26
Turnigy 2209 26turn 1130kv 15A Outrunner
Spec.
Kv: 1130rpm/v
Operating Current: 4A ~ 13A
Peak Current: 15A
Suggested prop: 9x4.7
Suggested Battery: 1300~1700mAh 3S1P
Weight: 46g
Dimensions: 27.6 x 28mm
Shaft Size: 3.175mm
Kv (rpm/v) 1130
Weight (g) 46
Max Current (A) 15
Resistance (mh) 0
Max Voltage (V) 11
Power(W) 0
Shaft A (mm) -
Length B (mm) 28
Diameter C (mm) 28
Can Length D (mm) 13
Total Length E (mm) 43
Update/Add my own data

Customer Data
13 thumbs up!
PROPELLER 2cell (7.4V) 3cell (11.1V)
- 7x4 APC 240 gr 510 gr
8x3.8 TP (SF) 380 gr 660 gr
8x6 GWS 410 gr
9x3.8 TP (SF) 450 gr 740 gr
9x4.7 TP (SF) 460 gr 690 gr
10x4.7 GWS (SF) 570 gr

with 20A ESC
very good motor.
Best Regards. Reply to this..
No replies. Reply now

[popeyepete]

Good luck mate, i done the same thing and got building a Extra 300 from RCPowers. Built-it from left-over foam board from work, may be a little to heavy.

Found some sites with heaps of plans for wet weather days;

http://www.willingtons.com/mymac/Plans_Download.htm

http://www.hooked-on-rc-airplanes.com/fr...plans.html

http://www.rcfoam.com/cart.php?page=plans

[kizza42]

Merged the 2 Luton build threads into one.

I reckon for a power setup, have a look at these combo's for inspiration: http://www.hobbyking.com/hobbyking/store...tegory=179

U wont be needing to throw too much power at this.

[smuzz]

...
There are 2 other things I'm not real sure about. One is that the plans specify some Lite Ply to reinforce a couple of spots in the wing. I need a 12" x 12" 1.5mm Liteply sheet. Can anyone advise on somewhere local that i can get some of this or if I can substitue something else for it.

The last thing is that I need a spar for the main wing. It needs to be 3mm x 9mm x 914mm. The instructions say I need spruce but I can't seem to find any locally. What would I be able to substitute for this? I was thinking maybe some pine but don't know enough about it to be sure.

Mick - a few of the local hobby shops sell Liteply (or equivalent) sheets. I picked up some from Berg's in Parramatta - can't remember if it's actually 1.5mm though. A few of the other places a little further afield would probably also be good bets "HStore" (Caringbah) or Vaggs (Miranda) but they're a bit of a drive.

As for wing spars - you'd probably get spruce from the same place, but a carbon-fibre square section might be also a possibility if you've not already cut the recesses in the ribs: http://www.hobbyking.com/hobbyking/store...oduct=8711

[~KevJ~]

kizz your right about those combos being enough power but honestly the shafts are like butter if you do buy one of those style motors Mick buy yourself 6+ spare shafts i tried them once, that was enough. the axi style outrunner the recoment would be so much better.. my 2 cents.
that said i think ingo uses hardened steel rod out of a CD player or something that are apparently better once machined to fit. sounds like lots of muckin around tho for no reason..?

for what its worth id try this:

motor:
http://www.hobbyking.com/hobbyking/store...oduct=5686

prop:
http://www.hobbyking.com/hobbyking/store...oduct=9845

esc:
http://www.hobbyking.com/hobbyking/store...oduct=4312

battery:
http://www.hobbyking.com/hobbyking/store...duct=14695

i reckon that would get you around 600-700 grams of thrust at around 13-14 amps or around 150ish watts.. battery capacity was just a guess , if it says you can carry a bigger (heavier) batt in that airframe all the better . cruise around at under 10 bucks a battery for 10 minutes at a time.. nice..

good luck with the build whichever way you go mick i reckon it looks like a nice project , looking forward to watching the progress pics

[Kedumba]

Hi All,
Thanks for the replies, thay have been fantastic. I picked up the Spar & Lite ply today from Hobbies in the Hills in Castle Hill so now I'll be able to finish the wing and start on the fusalage.

Next step is trying to figure out which motor/ESC to get. There are so many choices, but at least I have a better idea of what to look for when I get a chance to sit down and have a proper look at the Hobbyking website.

[smuzz]

I picked up the Spar & Lite ply today from Hobbies in the Hills in Castle Hill so now I'll be able to finish the wing and start on the fusalage.

Ah, yeh - forgot about Hobbies in the Hills, and there's also Castle Hill Hobbies. I didn't mention Ultimate Hobbies because I can't remember seeing any timber stock when I've been there (but they might have some). Anyway, that's good news!

[paulj]

Only timber stock I've ever seen in Ultimate Hobbies
was a little bit of balsa. Don't think they are really into
stocking for the scratchbuilders

[Kedumba]

Hi Again,

I've had a really quick look at the HK website and I think I've narrowed it down to 2 choices.

Either the Turnigy 2209 26turn 1130kv 15A Outrunner which is the one i'm leaning towards as suggested by Kev, or maybe the TURNIGY 28-30-azj 14A 1100Kv Brushless Outrunner. I'd really love some feedback on whether I've made the right choice or not.

Actually, now that I've had the chance to write and think about it a little, I might go with the suggestion that Kev made, with the exception of the batt. I want to try and use my exsisting 1800mha batteries that come with my trojan, that way I can save some $$'s there.

Thanks all, I really appreciate the input and help. This is my first build so I'm learning as I go and I'm having fun doing it. Hopefully will get some more pics up soon.

[~KevJ~]

hey mick that 28-30 you listed looks a decent setup as well probably wouldnt matter which way you went .. unless anyone else has actually tested either/both of these motors? would be good for someone else to post an opinion also as i haven't got all that much experience with power setups under 400 watts..

still i do think you will be right as for the batts you should be able to use those 1800mah's in that high wing , it would have to be creating alot of lift i reckon ,for the type of flying that planes designed for it should be sweet.

whats the wingspan going to be?
and total weight without battery you think?

[Kedumba]

whats the wingspan going to be?
and total weight without battery you think?

According to the magazine:
Wingspan: 35" (889mm)
Fuselage Length: 28" (711mm)
Wing Area: 1.7 sq ft. (0.16 sq. m)
All Up Weight: 12-25oz (595-709g)
Wing Loading: 12-15oz /sq. ft. (3.7 - 4.6kg / sq. m)

Of course individual results may vary!

[~KevJ~]

whats the wingspan going to be?
and total weight without battery you think?

According to the magazine:
Wingspan: 35" (889mm)
Fuselage Length: 28" (711mm)
Wing Area: 1.7 sq ft. (0.16 sq. m)
All Up Weight: 12-25oz (595-709g)
Wing Loading: 12-15oz /sq. ft. (3.7 - 4.6kg / sq. m)

Of course individual results may vary!

I wonder what sort of thrust ratio you need for a high wing plane like this, I always hold my planes vertical and if it holds it's own weight at WOT then good if it climbs the better but I don't think that applies here, if that weight you gave is without battery then you add you batts at say 170g that's about 900g all up flying weight so with a SF prop 9x4.7 it will have maybe 800 g thrust which should cruise that Luton around nice and scale I reckon.. Sorry for flooding your thread mate I just like all this sort of power discussions

[Kedumba]

if that weight you gave is without battery then you add you batts at say 170g that's about 900g all up flying weight so with a SF prop 9x4.7 it will have maybe 800 g thrust which should cruise that Luton around nice and scale I reckon.. Sorry for flooding your thread mate I just like all this sort of power discussions

I don't know if that weight includes a battery or not, the mag is pretty scant on details like that. I'll defintaly be putting it on the scales when I'm finished though to find out.

Don't worry about flooding, since I have no idea about how to work out power/motor/thrust thingies, it's all great info and very helpful to me!

More pic's soon as I have the day off today and I'm gonna try get some more done.

[Kedumba]

More Pictures.

Next Step, trim up and round off the wing tips. Once they look ok, then glue in the 8 outer ribs and wait for the whole lot of them to dry.

While it's drying, cut out the Dihedral Jig and the inner Ribs, plus the wing braces. Once the ribs are dry, test fit the main spar to see if it all lines up, which it seems to do.

Now time to put the 4 deg Dihedral into the wing. Lightly score down the center line, cut a small V notch into the Leading and Trailing edge, Add some weight to one side of the wing and lift the other gently, slide the Jig underneath and glue it all. Back away carefully and wait till it dries.

While waiting for the glue to dry, start on the airelons and center bit of the trailing edge. The round shape of the wing is starting to come up now.

[~KevJ~]

good progress mick , its coming along nicely

[Kedumba]

Glue in the 3 internal Ribs, the main spar and the remaining Dihedral Brace. Note the Servo Wire holes on the inner ribs.

Add the Trailing Edge block and wait for it all to dry. Once dry it's time to start sanding. Rounding off the Leading Edge and shaping the trailing edge.

Wing is now mostly finished. Just needs to have the Servo's installed, wing mounts attached and then covered, attach the airelons and it's ready to fly!

[samste]

Happpppppy Birthday Mick

[Kedumba]

Happpppppy Birthday Mick

Thanks Steve. Had the day off work so I had some more time to work on the build.

Next to do is the tail plane. this was pretty straight forward. Cut out the pieces and build it on the plan. Glue it all into position and pin and wait for it to dry.

While waiting, cut out and shape/sand the elevator. Once it's all dry, some more sanding to get it a nice round shape.

Now the vertical stabiliser. Simply cut and sand. Dry fit to make sure it's all the right size and shape. Starting to look real good!

Just enough time to start cutting out the fuselage sides, base, bulk heads and other bits and pieces.

[Kedumba]

Some More pics. This time of the fuslarge going together. First off, cut all the bits out then just glue them together. Fuse is kinda build upside down so the big open bit is at the bottom and the base is the last thing to go into place.

Once all the glue is dry, a couple of balsa blocks are sanded into shape. These go on top of the fuze to form the outline of the cockpit. Behind this a number of stringers will run down to the tailplane to give it a nice rounded look.

I'm almost up to the point where I need to start thinking about covering. Can anyone explain to me how this part works? What do I need and where is the best place to get them from. Not totally sure of the colour scheme I want yet but i'm liking the almost white and red strips of the model prototype. I like the vintage look. I've also googled up some other Luton colour schemes I like, esp the Red Baron one.

[smuzz]

Well Mick, when it comes to covering I've only tried "Solarfilm" (since the mid 1970's when we used tissue paper on nitrocellulose dope). I've used Solarfilm on both framed structures and solid surfaces and it requires a different technique with each. The instructions on its use are usually included with the film, but the only thing that I've found tricky is getting the temperature of the iron correct - I was using a temperature which was too low to start with (being cautious) and that didn't help at all. A couple of things I did discover ...

1. With a frame structure like the upperside of your wing, tack along the outsides first. Don't be afraid to pull up sections you've already tacked down if there are wrinkles, you can re-tack these down again with the toe of the iron. This tip isn't mentioned in the instructions I've seen that come with the material.
2. With sheeted sections like the underside of your wing, you must start from the centre with the iron and work outwards to avoid wrinkles.
3. If you get some wrinkles that are difficult to remove by lifting the film and re-setting it, then don't worry too much because you'd be surprised at how even tight wrinkles can be removed by gently rubbing them with the toe of an iron.
4. As for warps (more likely in the wing of course) it's possible to get rid of these to a large extent by getting an assistant to twist the wing against the warp while you move the iron over both surfaces - this can happen hours or days after covering the wing. It's one of the things that makes the heat-sensitive films much better than the old tissue and dope techniques.

But, that's the extent of my knowledge - there are dozens of different types of films available and I've only tried Solarfilm. I've also only used an old clothes-iron with some flannel from an old westie-style shirt stretched over the iron and held in place by hand. I've had good results on using it on wings and on sheeted tail surfaces, but I've also tried putting it directly over foam as a "skin" and that was a disaster - I'll tell you about it some time at the field!

Good luck mate and remember that if it all starts going wrong, that you can rip it off by hand and still have your balsa handiwork ready to go again in another attempt!
SteveM

[paulj]

the heat shrink covering film that HK sells is good
and quite cheap too
Kev used that on his easy sport build and I tried some when I had the tucano

[~KevJ~]

yeah i used three colours, two from hk and 1 from a local hobby shop, the hk film was much easier to work with , the film was more durable and you could ease the temperature on and adjust, you can shrink , then you can shrink and then shrink each time you do it begins to shrink at a higher temperature, i found the hk to have a wide temperature range (meaning its good, if that all makes sense , its very late )

[paulj]

Hey Mick,
Just wondering if you can give me an idea of how much it
has cost you on Balsa so far.
As you know I've been using depron and would just like an idea
of typical cost difference.
I see you bought the balsa from Bunnings were you able to source all the
necessary sizes from them and was the stock nice and straight?
thanks

[Kedumba]

Hey Mick,
Just wondering if you can give me an idea of how much it
has cost you on Balsa so far.
As you know I've been using depron and would just like an idea
of typical cost difference.
I see you bought the balsa from Bunnings were you able to source all the
necessary sizes from them and was the stock nice and straight?
thanks

The Plans I'm working from are english and use a really bizarre mix of imperial and metric measurements which is making things a bit of a challange. For example, in the same sentence it will say "glue the 1.5mm ply doubler to the 3/32" balsa sheet". I'm a metric kinda bloke so the 3/32's and the 1/8's and what not don't mean a great deal to me so i've been doing a lot of conversions.

Anyways, the plans call for 4 or 5 thickness's of balsa, namely 3/32", 1/8", 3/16", 1/4" and 3/8" (and the Americans don't like metric because it too complicated ) which converts to 2.38mm, 3.175mm, 4.76mm, 6.35mm and 9.525mm. I took these thickness on my list of paper to Bunnings and came away with the following: 2.5mm, 3mm, 5mm, 6.5mm and 10mm which to me looked pretty close. These were standard 100mm wide by 914mm long sheets which seem pretty common. Anyways, from memory, I think I would have spent approx $45 in total from Bunnings.

As for the wood quality, I'm new to all this so I wouldn't know if it was great or not, however, I simply looked for peices that were flat and not warped as well as no obvious defects like knot holes or splits and I had no troble finding the dozen sheets or so of what I needed and I've had no trouble working with the wood I did get.

The LitePly and Spruce I had to get from Hobbies in the Hills and they cost me about $10 for the ply and about $4 for the Spruce. So all up I would have spend about $60 in wood, but I will probably have some left over as an incentive to start looking for my next project.

The Ply came in a huge sheet, about 300mm by 914mm approx. I only needed a few small pieces so I've got plenty left over for my next project as well.

[gbanger]

Hey Mick
Im an old school engineer so I learnt both Imperial and Metric while I was doing my trade.
To cut through the bull. With almost everything in the enginering industry these days, the close conversion is suitable.
ie: 1/8" is 3mm 3/16" is 5 mm. Sorry you had to find out the hard way.
Gazz

[paulj]

thanks for the info Mick.
I'm building a bandit from depron and I estimate that so far
it's cost me about $30. I won't have much left over so probably cost are
similar. You will end up buying covering material while I will be fibreglassing and painting mine.
Interesting comparing both methods.