Topic: Luna 2 build.

Hi guys,Alittle advice if you could.I am building a Luna2 and have a question regarding the fixing of the nose(contains the rudd and ele servos) to the fuz.There does not seem much of an overlap to epoxy too,should i strengthen this joint with glass mat/carbon tows etc and has any one ever had the front come unglued in a hard arrival.....I would rather make it quite strong now at the expense of a few grams than have to refix it later after  a hard landing and then try an strengthen it.......what do you all think?....Chris.

Hi Chris,

I have a Luna 1 so might be slightly different but after an arrival my nose did come off ( not mine but the models it wasnt that bad a landing  ) so after my experiences i would say beef it up a bit if possible.

Karlos

I like CA for fixing that sort of thing - it doesn't look as strong but it is - it wicks into all the nooks and crannies - hit it with activator and it fizzes and expands too!

Thanks
           ,I had thought about medium cyno but nobody else had mentioned it.What I had in mind was to assemble it as required ,cyno it then reinforce with epoxy, carbon mat and/or tows afterwards.My other cunning plan was to fit a carbon ballast tube along the bottom of the fuz with a bottom loading ,shotgun type access.I could use the tube to reinforce the joint as well and hopefully this would put my mind at rest......Thoughts anyone?

This Is my first mouldie "build" but I have owned two different mouldies previously.I am forcing my self to learn about assembly/installation/setup rather than have it done already for me.I have just learned what "potting" the nose cone is from a you tube presentation.I did wonder about the nose cone pushing back over the front of the fuz in a hard landing,even though the rim of it has a ring of carbon tows...you never stop learning..Chris

Mmmm. Potting the nose eh? Good idea. Check this out though:

Sam's bad day #3

Check out the whole thread for advice on a build and what can go wrong with a Luna. He does loves his Luna now. Mine had tail issues I never got round to resolving.

When I plotted my build the first thing I wanted to do was a little bit more carbon in the corners around the wing saddle and a layer of carbon on the top of the saddle.
The ballast tube idea sounds neat, like a Typhoon, but will it affect gear placement above it? And won't it be a bit long?

OOOOOOHHHHHHHH! see what you mean.The moral is just enough p38 but not too much....problem is how much.I think before i do that i will make an epp plug to go in the radio area before covering with cling film.this should stop any filler overlapping the fuz and stopping it coming off..well that's my theory!

Regarding the  wing mounting strength.I don't know how old your Luna is but this one ,bought recently has masses of carbon all around the wing seat an surrounding the bolt captive nuts .It looks as thought it was put in during the manufacture as its between the layers of fiberglass.I was worried about opening out the wing seating hole to allow my mpx wing servo connectors easier access but realised i would have to grinding through the carbon so i will have to do this judiciously.

The ballast tube will have to be about a slug longer but its 24" at the moment ready to be cut down.It will leave about 7mm above the tube until its level with the rudder/ele servo mounting tray, this will offset my tiny fasst 2.4ghz rx as that's only about that thick anyway.At worst i could mount the sx first then the rx towards the front ish.
Again ,that's my theory looking at it so far.Does everyone think medium cyno will be ok for a first fix of the nose,then epoxy/balloons/mat /tows later??...Chris

I am currently building a Luna 2 for a friend , I didn't see that the nose fixture would be a problem, Just remember to rough up the inside and the keel where they join , Nothing worse for epoxy than a shiny surface to bond too

Lee

progress report:

I went for the cyno method for the front half of the fuz.I agree,feels  a very strong bond and with a bit of fizz filling any gaps.Also i have fitted the ballast tube on the fuz floor as i previously thought  and cut a slot in the fuz to bottom load the slugs.It works well,I can load 10 slugs at 51g each(510g),they are brass and 16mm diameter,30mm long.One of my Ideas was if i was fitting a carbon tube in the fuz i might as well make it structural and aid in the joining of the fuz halves.

It will have a little carbon mat around it and over the joint,wetted with epoxy for good measure.So far so good.

Rudder horn is fitted,went with the  supplied grp horn and a "z" bend in the wire(no slop),cut a slot,cynoed and epoxy ballooned etc...will use hitec hs 5085 for the elevator and rudder servos.

Wings have been ground out and the flap horns (brass)angled at 45deg and lined up with the hinge line,12mm from hinge line to horn hole.So will use 9mm on the servo horn(Hyperion wing sx)I modified some hitec 125mg mounts to fit the Hyperion ones.Just got to follow mikes master piece of flap info install next.

During the install i removed half the trailing edge subspar and carbon towed the remaining half for good measure.I agree those servos can move over 140deg at least and will make the flap setup easier.I have found the flap centre offset mix on my Futaba tranny(sorry mpx guys,it can be done on my 12fg with ease) so i will not need an "ice cream tray tx " after all...phew!
Rx will be either Fasst r617fs or R608fs and batts eneloop AA 2000mah.Aileron servos will be s3150 futaba as i have them spare.

So that's about it for now..will keep everone updated if they are interested in my virginal first crunche build...Chris T

I am going for the nose cone "potting"tomorrow.I am still nervous after reading the Australian guys problem with the filler going over the lip and holding the cone on...The advice of the f3x building clinic on you tube is more is better than less filler.....well that's wrong for a start.

Too little,well the nose cone comes off and you have a neat yob you can always top up with filler in the nose later.....Too much and the nose stays on..no brainer really......we will see tomorrow...Chris

YouTube             - F3 Building Clinic - Nose Cone Fit Out

for reference.

or just don't do it like everyone else....

dam....never thought of that

The nose is fine 'as is' on the Luna - been flying mine for a while now anyway and it's still 'nose' shaped 

you must be good at landing then!

Do you like it..I am dying to finish it and fly it but i am stopping my self from rushing it.Its an in between mouldie for me...i had a micro floh and a Valentia Dogan..this should fill the gap nicely...Chris

Mmmm. Potting the nose eh? Good idea. Check this out though:

Sam's bad day #3

Check out the whole thread for advice on a build and what can go wrong with a Luna. He does loves his Luna now. Mine had tail issues I never got round to resolving.

When I plotted my build the first thing I wanted to do was a little bit more carbon in the corners around the wing saddle and a layer of carbon on the top of the saddle.
The ballast tube idea sounds neat, like a Typhoon, but will it affect gear placement above it? And won't it be a bit long?

Mr ED,what tail issue did/do you still have and does it affect it..chris

The nose is fine 'as is' on the Luna - been flying mine for a while now anyway and it's still 'nose' shaped 

C'mon fella, you torque the torque when it comes to batteries, soldering looms and the like, but not when it comes to mechanicals?
I've not had a mono heatsleeved staggered  joint fail or had a reduced feed wing loom not work and yet you won't acknowledge the potential benefit of a potted nose?
Baaaaad editor.  

My Luna problem was shipping damage that Sloperace had trouble getting sorted by the factory so they took the Luna back. No problem with the design of the Luna or Sloperacer, just the factory.

Thanks guys,I am still going to pot it...I agree mr ed..its a mechanical thing.even when pushed on fully the nose cone will move up/down..side to side by a couple of mm and all this effort i am putting into holding the front fuz on will be wasted if the cone gets a knock and rides over my strong front of the fuz and takes a chunk out of the wing...not that i will crash it...as i said before i build for flight and the slope terrain landing area not for crashing.Its all too easy where i fly to hit a clump of long grass/heather and demolish the front,even on a good landing...chris

you must be good at landing then!

Do you like it..I am dying to finish it and fly it but i am stopping my self from rushing it.Its an in between mouldie for me...i had a micro floh and a Valentia Dogan..this should fill the gap nicely...Chris

that's not the point. NEw nose cones are cheaper than new fuselages. 

Potting nose cones is just a recipe for something to go wrong when there is no need.  It seems madness to me. The inner nose cone/till on models is not designed to take shock loads or impacts. On a lot of models they are quite weak, but then they don't need to be strong - they are there to hold the servos etc.

ON most models yes you can crack the nose cone (typically down the seam) but if you hit hard enough to actually go through the nose cone and into the innards of the model you are probably talking broken wings and trashed fuselages anyway.

I agree - treat the nose cone like a crumple zone in a car - much better for it to be broken than the important bits inside!
Looks like you're inventing a solution to a problem that doesn't exist to me...


Simon

they actually don't split and go over the fuse anyway from what I have seen. I think what happens is that they crack by being bend out of shape and the shock rather than being forced over the fuselage.  Even if they did the force you would need the rest of the model would probably be binnage anyway.

I am not " inventing a solution ",the solution already exists,I am just agreeing about the benefits of such a process.
On a very  hard impact(crash)there will be little resistance from the nose cone any way as if its not potted it will just be pushed back and cause extra damage.And i agree even if it is potted there would be masses of damage anyway,but i am not expecting the potting to overcome a crash.

I am concerened about the everyday knocking and strength of it if left "as is"and dont want to keep re glueing it every time it gets a knock which would not be classed as a hard landing.If you have a luna you will see what i mean about it moving up /down etc a little and it does seem very flimsy.

it just seems strange to anchor the nose cone to part of the model that you are concerned is not strong enough.

From your previous post about landing in heather /grass  I dont think your going to need to worry about the nose . You should worry about breaking the tail just in front of the fin though when the plane gets whipped round in a less than perfect landing ...its a lot weaker there than the nosecone is ....

If you Analise the forces involved,when potted, if the cone receives any force acting on it,by being "connected"to the stronger front of the glider it transmitts any force through the car filler and onto the front of the fuz thus not breaking like an egg.Ie, it actually make it stronger by the association with the fuz.

I repeat,Its not about crashing..its all over then any way,I agree,It about every day strength.I suppose i have been spoilt by the micro floh and the dogan,they are both very strong on the fuz area and can be buried sixinches into the ground without damage.I am not expecting similar strength,and trying to be realistic but can see a little flimsy ness in the stock build.

I also know/agree that over strength just puts the week point somewhere else but durability is what i am after.I get the feeling this is a splendid model and as such ,it will be flown until it wares out,hence my reasoning thus far..Chris

From your previous post about landing in heather /grass  I dont think your going to need to worry about the nose . You should worry about breaking the tail just in front of the fin though when the plane gets whipped round in a less than perfect landing ...its a lot weaker there than the nosecone is ....

How do I "pot" the tail then?

Could someone explain to a simpleton like me what was going on with that RCgroups /samotage thing? I'm lost I have a luna to build
I was just going to build it.

samotage had a Lemon of a kit where nothing fitted correctly but decided to fix it himself,all be it ,very well.I/we here are discusing the finer points of a luna build ,which for me too,is my first mouldie build.The potting we are refering too ,samotage had some filler spill over on to the fuz lip which held the nose cone on by mistake thats all.I am trying to avoid such a problem,of course the easy way to do that is not to pot it in the first place..chris

you must be good at landing then!

Do you like it..I am dying to finish it and fly it but i am stopping my self from rushing it.Its an in between mouldie for me...i had a micro floh and a Valentia Dogan..this should fill the gap nicely...Chris

Do I like it - it's the BEST all round glider I've ever flown - period 

Simply put, the Luna does everything really well and is so easy to fly - in fact if you break the nose cone of a Luna landing then you should be made to sit in the corner with an Zagi until you've calmed down!

Do I like it - it's the BEST all round glider I've ever flown - period 

Simply put, the Luna does everything really well and is so easy to fly - in fact if you break the nose cone of a Luna landing then you should be made to sit in the corner with an Zagi until you've calmed down!

C'mon fella, you torque the torque when it comes to batteries, soldering looms and the like, but not when it comes to mechanicals?
I've not had a mono heatsleeved staggered  joint fail or had a reduced feed wing loom not work and yet you won't acknowledge the potential benefit of a potted nose?
Baaaaad editor.  

True - I think I'll dip all my models in 5 min epoxy right now and go rip out all the safety redundancy wiring, just to give a bit of an edge to the risk factor eh

I'm a belt and braces man - it's probably why I'm still flying 'stuff' I built a quarter of a century ago (NO ageist jokes than' yooooo)!  Here's a tale - I was putting the wing on a nice little Hangar 9 ARTF Texan on the Nat's showline a while back - a VERY experienced flier (modeller...?) asked me 'what I was faffing about with' - in fact I was tying my servo extension lead into a single knot so that when it pulled, it pulled the connectors TOGETHER (rather than apart) - 'Oh I've never had a problem' (he says....)!
Nope - never have a problem with anything until you do!

There's 10 ways of doing every job - use what works for you!

Could someone explain to a simpleton like me what was going on with that RCgroups /samotage thing? I'm lost I have a luna to build
I was just going to build it.

Sam is a really good modeller and a REALLY nice guy

(which is why we WON'T mention the Luna - eh Sam............


Well ok - we've mentioned it once or twice but I THINK we got away with it.................................

Well chaps,Its done.The nose cone is potted now and still removeable.It took all of 10 mins to do the work ,but a week to research it and build up the courage.

I agree,If I cant do a superb landing with what Ive read with a Luna..then its time to give up the hobby.

I rather took a very sad and accurate look at the space between the end of the fuz and the end of the nose cone and sort of calculated how much filler i would need,this then would make it impossible for the filler to squash where its not needed....it worked......now whats next...Chris

I don't have a Zagi, but when I've flown mine, I'll sit in a corner with my WT if that's okay

I don't have a Zagi, but when I've flown mine, I'll sit in a corner with my WT if that's okay

Not sure on the WT but if you can get someone to loan you an SAS Thing, then that'll do 

Outside bet - an Obilisk.............

Sam is a really good modeller and a REALLY nice guy

(which is why we WON'T mention the Luna - eh Sam............


Well ok - we've mentioned it once or twice but I THINK we got away with it.................................

I don't doubt it Steve.  Just amazed me that someone  could f**k a brand new glider by potting the nose in case it actually broke on landing. Therefore breaking it. I suppose it saves on petrol and walking up the hill I suppose. Is this nose area a problem on lunas? I heard someone mention it's like an eggshell. Did you not do the egg shell strength experiments at school by dropping it on it's end?

Actually the Luna is pretty tough in general use - it's a 'glider' so it's not meant for bashing - tis meant for flying.

Mr ST put his in a flat spin down to a landing on t'horme (sort of on purpose - fecking about with it) with no issues - my chum's new one dropped from 20 feet onto the ground when he overcooked a landing into a stall - mines had heaps of flying and nothings broken yet!

I do know a man who sawed his wing half through by sliding it along a barbed wire fence on a landing - even that lives to fly another day.

Anyway - the nose is no better or worse (IMO) than any other tool of the Luna's type!

Er, 'Scuse me Mr. I put it into a few flat spins down to landing. AND it was ballasted!
 

Er, 'Scuse me Mr. I put it into a few flat spins down to landing. AND it was ballasted!
 

But you WERE 'Phekking about' - no 

 Landing like this is actually pretty safe in the UK's nice soft stuff. But I hadn't taped the nose cone on, and the model bounced back out of its nicely planted nosecone and then landed again on its inner nose.

It's funny, I always harboured a notion that I was thankful that the model was able to bounce back out of its nosecone when I landed like that.  OK, I have never had the "re-landing" problem you had, I've always ended up with the plane gently lying flat on the ground a few feet back from the buried nose cone!  But, I always thought that the "bouncing back" thing was a good way of expending the energy involved without doing grave damage....?

I am in the midst of building a Luna , I saw/see no need for potting the keel/nose/front bit at all, I have preped the joints ( roughed them up a bit ) used good epoxy and put them together straight, The joint is as strong as it needs to be to sustain normal working conditions, If the Pilot ( not me ) stuffs it in then it will come off , ANSWER : dont stuff it in . At the end of the day the Luna is not sold as an indestructible model, Its a moldie and should be flow LANDED as such , then there won't be a problem at all. Its easy to over build these things and make ten times more work just for the sake of it . Why bother , Put it together properly/safely and go fly the damn thing

Nuff said

Lee