I allready did that step and it should now be dry for removal being pined to my working board. I spliced the 1/4" balsa sticks by cutting at a 45 degree angle.

I agree that one should use a saw jig for splice. Fotunatly I had an x-acto saw jig out of aluminum from my previous build that is very handy.

Rate1

Before messing with the stab cores and jackets, mark them with felt tip so you know which jacket goes with which core and whether its is a top or bottom surface of the core and whether it is a top or bottom jacket (LH or RH).

Using the bottom half of the stab jackets (or whatever we call the foam bits that are left over when the cores have been removed) as supports (this keeps both halves level...just use paper sheets to shim-up either one so the cores are exactly level with each other (the depth of the jackets are not always the same), mate up the two halves so that you can draw two parallel lines across the joint a distance apart equal to the thickness of your dihedral brace (I used a piece of 3/32 liteply about 4" to 5" Long at about 1/3rd of the way from the stab LE and another brace about 2/3rds the way back from the LE rather than take the chance that I could bore holes for a Carbon tube in the correct direction). You can measure the depth of the core at each brace point (which gives the total depth of the brace at the centreline for each brace. You can (if you like) use trigonometry to calculate the depth at each outer end of the brace at each position or wait till you've cut the slot for them and then measure the depth at the outer end of your brace which should now be shaped like a squashed trapezium. Using the jackets automatically gives you the correct dihedral angle ...ie - none!

Thus, before you sheet the stab, cut the slots as above, check that the braces fit well and don't stick out above (or below) the cores by sanding using protection as described following to protect the cores, then go ahead and skin each stab using the jackets to hold the sheeting in place whilst the glue (or Z-Poxy finishing resin or whatever you are sticking your skins on with) sets off. When all is dry and edges sanded, you can then glue join the two stab halves adding the braces into the resulting slots with a dollop of adhesive, Z-Poxy finishing resin or whatever, whilst then resting on the lower jackets as noted above whilst the glue sets (weight them down so they don't move)

As an aside, before skinning I cut away small pieces of the cores at the TE and replaced these with little blocks of endgrain balsa to receive the hinge points and spaced accordingly. I also added the rear spars to each core (having cut the appropriate amount ... 1/4"...from the core TEs) and the tips ALL before skinning each half. The reason for this was to provide more glueing area for the balsa to balsa joints between skin and spars/tip rib...think about it. The LE spars were added after skinning. Now (IMPORTANT) use masking tape to protect the Cores when sanding these hinge blocks and the Tip and TE . Use the same method over the skins when sanding the LE. You can remove this protection just prior to the last sanding passes to ensure there is no remaining ridge across the joint to be felt. In fact, use masking tape (I use the blue coloured 3M stuff) anytime you don't want your part sanding in the area that you are not directly watching...don't ask me how I know this!

Edit:
It goes without saying that the jackets need protection from any overspill of glue when used as supports...I use the backing film from Solarfilm, Oracover, or whatever...glue doesn't seem to want to stick to this be it resin or cya or whatever

More anon

Cheers

Rate1 ..you will have lost a little strength continuity across a 45 deg splice...maybe add a short (maybe 1" long) buttstrap across your splice..you can chamfer the ends of this splice (45 deg!?!!?) which will reduce weight and also help transfer any load back into the adjacent parts of the main longeron. I also have the xacto "mitre" jig but didn't use it since 45 deg leaves far too insufficient joint area for a splice ...save that for making gussets and making triangular corner joints. Glue these buttstraps to the corner between the side skins and the longerons.

Cheers

Great input Superworm.

I have heard about using hardwood inset into the foam core where the horn will be. However I doubt I will manage using such hard material and then sand it flush with the core without altering the original profile. I will stick with balsa inset for the spot where the horns will be mounted instead.

Ah..., I will look into that buttstrap. Perhaps capsule this joint with some epoxy?

I agree Rate1..instead of the hardwood (dowels) use a block of reasonably hard end grain balsa (ie the grain to go in the direction of the horn bolts).. Use the masking tape to protect the surface of your elevators whilst you sand them down to shape...masking tape to completely cover the exposed surface....whilst sanding you can watch some of the elevator some of the time but you can't watch all of the elevator all of the time (now where have I heard that before ???) Maybe even consider fitting these supports before you skin the elevators....as long as you remember where they are when you come to fitting your horns! (note, I actually bought the recommended forstner drill bits to drill the hardwood dowel horn supports. I shall use these bits as decorations in my workshop!

Epoxy remains heavier than balsa!

Cheers

I looked into this fostnerbit, very expensive, as recomended in the manual for these horn mounting blocks, but will instead use a sharpend brass tube (of proper diameter) to drill/twist/cut a neat hole into the foam core where the balsa bit will be inserted. After this I will follow your advise of masking the exposed foam while shaping the balsa insert flush. Then mark on my plans its exact locaton before sheeting. Afterwards one could just use a needle if uncertain of the horn mounting location (if forgotten to mark its position on the plans).

ok guys, i'm back from a break during which i've been doing research, goofing off, etc. etc. etc. i really hate to tell you guys i'm not going to be able to do the 1/4 scale 300 with you. while i was taking my break and contemplating my next move, i happened up on the deal of a lifetime.....or at least in my lifetime.

27% C A Models (columbo andersson) Extra 300L..........only bad thing is i'm not going to get to enjoy the build with you guys, as this kit is 95% built already!!! the only things left to do is cut one elevator, hinge both elevators, rudder, and one aileron! then it's basically ready for covering! i never would have imagined that i'd happen up on this one!!!

ok so here's the story, last night we went to see a guy (fellow flyer) who had bought out a retiring flyer (retiring for reasons unknown). he had this plane and i wanted to look at it (i didn't go for the plane but to see what else he'd gotten in the line of building tools, flight line equip. etc. after i'd gave the plane a "good going over" i asked him what he was asking for it.
when he named his price, i just about fainted.......i repeated the price to him to make sure i'd heard him right. i had heard him perfectly the first time! so without further makings or even trying to haggle over the price out comes the wallet and i paid the man. loaded her up and brought her home........

now i'm in a pickle about what to do next, i had planned on buying up the servos i'd need along with the engine, ignition, batteries, etc. while i was building the plane. now that timeframe is shot so i'm looking at a motor and servos a lot more quickly....(at least by next summer, since i've got a couple projects going now that i'm going to finish before starting.....er finishing rather the extra.....

so what do you guys think?

Rate1...you b*gger:::::

you just reminded me how much I paid for them...will now have to get them gold plated and present them to wifey as new-fangled earings

More later...gone to kip

[X(]

What do i think... Very very nice.

I was thinking about the 24% CA Extra but heard that the 27% was flying so much better. Apperantly these CA Extra's are pattern style awesome planes. However, as you know I ended up chosing this Lanier instead. Congrats on scoring a great deal and for a beutiful plane. A shame you will not partisipate on this thread but perhaps another time and another thread?

Superworm, to be honest with you I could actually use one of those fosterbits for the moment as they would be great to use drilling lightening holes. Just like the ones there is on Parrthd's CA Extra. Then again as earings why not! ...poor wifie...

Talk soon,

What do I think??


OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOHHHHHHHHHHHH HHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!!!

You are what is known in limeyland as a jammy barsteward....never heard of CA models over here (unless its "Chief") but your Extra looks like the mutz nutz

Enjoy completing the build and the flying when its done. Please come back here and post pictures for us when yer done.

Cheers

parrthd's Extra was a reallllly sweet deal, and it's a beautifully built plane.

The problem with dremel tool is it is just too hard to put it aside.

F1 former stock: 67gr or 2,36 oz
After it turned into a swiss cheese: 50gr or 1,76 oz
--------------------------------------------------------
Weight reduced: 17 gr, 0,6 oz (26%).

Oh, the fuz is slowly taking shape...


A though, perhaps I am going out too hard with this weightsaving idea? ...well, well at least it is fun.

So far I have narrowed the reductions down to:

Carbon fiber wing tube: 2oz
Contest balsa sheets: 10 oz
Fuz sides: 2 oz
Change to 15 light weight 1/4" balsa stringer: 1,65 oz
Fuz Bulk heads: 0,47 oz
F1 Bulk head: 0,6 oz
-----------------------------------------------------------------------
Total weight reduction so far: 16,72 oz, or 1,05 lbs.

Putting F1 where it belongs...

1lbs. in a 25% plane is a lot.

Well thank you... ..but I am not done yet... *Revised weight calculation, see previous post*

In addition there will be further weight savings:
Not knowing if I remember all of the planed weight reduction tricks I had in mind...

Lipos
Tru Turn Lite backplate spinner
Hopefully Vaccum sheeting the wings
Fiberglass cowl and pants
Possibly Carbon Fiber landing gear
Replace turtle deck and canopy hatch for a lighter material
overall nice hardware, such as cf push-rods, hinges horns ect...

Other items to put into the plane:

YS 140 sport
Digital servos

Did I miss something?

I think every bit of effort you are putting into lightening this plane is well worth it. The Lanier kits, from what I've been told (never built one personally) are a bit heavy.

Lighter = better in aircraft.

If you can find it and have the dollars to do so, going carbon on the cowl and pants will net you big big weight savings.

Your build is looking really good!

being that this has been brought up.....any thoughts about the one i bought? i was thinking of just going with iron on covering but i'm still open to the thought of glassing and painting the wings and tail feathers....any thoughts?

also have any of you guys thought about gear setup yet?

i've got two hitec HS-625 MG high torque.......thinking of getting two more. these four will be on the ailerons and elevator halves....a fellow flyer has a crashed 33% pitts he's been talking of trashing. the plane still has a 1/4 scale servo in it. i was thinking of trading/buying/etc that servo from him to operate a pull/pull for the rudder...all this i'm going with 6 volt packs at 2000mah or larger packs.

Parrthd

Vaccum sheeting the wings in this build is refering to apply the balsa sheet to the foam core wings under vaccum. This ables one to use much less epoxy resin compered to regular sheeting technique, and to avoid any possible bubble formations meaning parts of the sheet that did not glue down properly to the foam core. Hence a better and much lighter weight (several ounces) end result.

Considering you have a 27% plane and are going for a gas engine I would like to have it glassed. However, as I recently found out when I was asking and doing research about glassing for my plane, there is skills and a lot of work into getting a good fiber glassed model. If done properly and correctly this is the way to go as it has superior finish and is only then as light as balsa sheeted foam core wing with plastic film. If you dont have these skills, including excellent painting skills, or does not knowing anyone that have done successfull jobs previously that could help you I would cover it with plastic film as in my case. Also one needs a proper workshop for glassing. Having this said, I think most CA Extra's out there is covered with plastic covering. If one does not have the meantioned skills it would be wise to learn the techiniqe before attamting such a nice model as the 27% CA Extra.

Im thinking to use Hitech digital HS-5645 all around on this plane (169 oz/6 V system) as they are affordable and has good performance but have not decided yet. However I will not use anything less than 100 oz servos on this 1/4 scale. Perhaps you should go for 130 oz? While on rudder I will follow the old saying "use as powerfull as the planes weight" wich has been proven great for me so far. This would translate to a 11 lbs plane to have a 176 oz rudder servo, or a 14 lbs plane 224 oz. I could accept dull servos on the ailerons and elevator if needed but not on the rudder. This is my opinion.

I plan to use a 1500 mAh Lipo battery running 6 decent servos. If you have all high tourqe servos and perhaps more than 6 servos I think using 2000 mAh is a good idea but not any bigger unless you want more than perhaps 6 flights without recharging. You will also need to think about your all up weight and to prioritice what you want out of your plane.

Superworm,

I really like your way of using balsa blocks for the hinge points at the stab TE, as well as joining the TE spar and the balsa tip rib to the stab foam core before sheeting.

Hmm, if I would go with the vaccum techniqe for sheeting my foam cores, inorder to save weight as this method uses very little resin for this process and apperantly offer an excellent end result since there is very little risk for bubble formations, do you think joining the balsa stab TE and balsa tip ribs before sheeting could cause any problems in the vaccum process? Knowing that the vaccum method is simulating an enourmous pressure to the foam core jackets and consequently to the cores themself. I am thinking about the risk that there might be less flex (ability to compress) in the balsa compered to that of the foam, when pressed together under the high pressure that vaccum offers, and possibly risking to get a non conformal compression of the "package" (different material with differend desity in the same process) hence risking the airfoil shape, dents crushed or varped?

Question #2:
How to take out a small amount of foam from the stab TE neatly, so i can house the small balsa blocks used for the elevator hinge points? Did you use a dremel, drill, x-acto blade...??? Do you use round balsa blocks or square shaped?

Mate, it sayes on your RCU header that you are from UK, by the sound of it a beutiful and tropical part of the commonwelth, according to what time zone are you trying to endure your days by? Myself, UTC +1.

C.

Hi Rate1

Yep! UK it is - Northwest England a few yards above Beatleland (Liverpool) and before you get to Bonnie Scotland. We are on BST (British Summer Time = Greenwich (London) Mean Time +1...I'll have to look up the definition of UTC! Maybe checkout our Club's website...I'm lurking therein somewhere as Club Secretary

http://www.blackpoolmodelflyers.org.uk

I think that if you don't go over the top with the pressure, it shouldn't be too much of a problem...I didn't use air pressure but used two old car batteries and several old model magazines to weigh down my skins whilst they were resting in (wait for it) the saddles....now I've remembered this as the proper term for the remaining bits of foam after the cores have been extracted...used the term "jackets" on previous postings....but you may have a point bearing in mind the two levels (balsa and foam) of compressiblity of these two materials....If in doubt, test it out (ie build a test specimen from scrap foam, sheet the sides with 1/4" and the top/bottom with 1/16" and then go vacuum bag it. If there is minimal "starved horse" look about the finished components, the high spots may possibly be easily sanded off.

Note then when you use this technique for the wings, you will already have cut-outs therein for access to the wing bolts and, most probably, the servo bays. the skins WILL sag over these cut-outs if they are not properly supported .. at least by a skin doubler in these areas. You may alos consider temporarily inserting the phenolic wing tubes, to support the bored holes that they live in, whilst the pressure is being applied.

I use a scalpel blade No.26 (always use such) in a Swann-Morton handle to cut out the foam for these rectangular blocks. I then used these as a guide for the knife blade when I cut out the foam for a perfect fit...they where epoxied in and then any slight excess was sanded off the surface using the masking tape to protect the foam as mentioned previously.

Parrthd

We talked about this further up this thread (near the bottom of Page 1 and P2 etc) ...check out our deliberations

Cheers

Superworm,

Thank you for that. I am thinking that I might just skip those balsa bits for the hinge points, risk of my screwing it up and I am not sure if I need them as the stab TE is fairly thick by itself. After all I am trying to save weight and are chaseing a weight reduction down to a small percentage in each part.
Yeah, you are right about using less suction on the vaccum system not to distort the wings if laminating/sheeting with the balsa bits already attached before sheeting. Lets hope I will get access to this schools workshop. Otherwise I guess I will have to do it the traditional way.

UTC= Universal Time Cordinator, meaning Greenwich as a reference. The term UTC, or short for Z (Zulo), is what the aviation uses so they all fly on the same time.

Well I been doing some work on the enginebox sides.

These enginebox sides weight stock: 87 grams or 3,07 oz
Weight with lighening holes: 77 grams or 2,72 oz
------------------------------------------------------------------
Reduced weight: 10 grams or 0,35 oz (11%)


These are now installed and it is time for lunch...

Hi Rate1

Looks good...particularly the firewall
In spite of it having a YS 140 to support, its big and heavy enough as is to support your local friendly brick-built outhouse.....as is the similar part that mounts the cowling.

I never really thought that Lanier kits were particularly heavy (being a Weights Engineer) but these two parts really are heavy. You must bear in mind though that it would cost much more (and you & I would have to pay) for Bubba at Lanier to supply these parts with these lightening holes already cut out...its far cheaper if we do it!.

Go easy with those enginebox sides fwd of the firewall tho'....there is an awful lot of Shear and bending moment to be reacted here on the (hopefully infrequent) heavy landings...apply a few "G"s to the weight of your YS and you'll see what I mean. You can make the odd lightening hole here but their location is equally important so that you still have a good loadpath back to the firewall

...back to work...later...

Cheers

I agree that the loads infront of the firewall are great. Therefor I have decided not to make any lightening holes there. All the lighening holes is on the firewall and aft of it. As can be seen on picture.
The loads do however distrubute when it reaches the firewall though. Part fo the forces goes thru the firewall conected to the fuz sides, and another part thru the engine box sides to the wing spar directed to the fuz sides, finally there is the F2 fuz bulk head -> fuz sides again that has to absorb some as it also is connected to the enginebox sides. But as you meantioned, in front of the firewall there is only the engine box by itself and I dont dare to manipulate with this area.

Also I am planing to leave the part that is mounted against the firewall and holds the cowl as is. This as I don't want crap like fuel and dirt coming into the fuz. But yes I agree with you these two parts are heavy.