Giant Cod Edge Profile ARTF build blog (of sorts)

[Stephen Jones]

Hi ,

 

My input for wot its worth , I took my edge to a indoor meeting for its first outing which wasn`t  such a good idea as i broke it . I repaired and took it the following week for a fly at our flying field on a mild windy day . It was more like flying a kite than a plane . As i did not know where the balance point was to be , nor how much control throws to set up . It was tail heavy and slow to roll but easy to fly , i could bring it in very close to me and plop it on the ground in front of me , i too got about ten minutes  flight before i decided i had enough fighting with the wind . 

 

I have since put a larger prop on it and increased the control throws , This is where i discovered the servo lead from my esc was not plugged all the way home which would explain way i broke it on its first outing  .

Although i am still waiting to take it out again i have tested it in my house and it now seems to be able to prop hang now .

 

 here is  Waiting till next time out .

[Bob Moore]

I agree about flying in a wind, judging from my experience in a gentle breeze.  I can't imagine flying it inside though.

 

I dropped mine in close to land and even thought about catching it!

 

What motor/battery/prop combination do you have to be able to prop hang?

[Stephen Jones]

Hi Bob ,

 

Here is my set-up 

Motor BRC  A2212-15T = 930 Kv  120 watt

Prop 9.4.7sf

Battery 20c 1000 3 cell

 

2 x 9g tower servo

1 x 15g high torque servo

PCM1024 6cH receiver 

 33amp  Esc

 

AuW 380g including two pieces of triangle balsa use to repair damage 

Edited By Stephen Jones on 02/11/2010 23:08:41

[Erfolg]

Hi Stephen and Bob

 

As with many things which are new to me, I tend to worry about identifying what is important.

 

To help me, I have reviewed the ballerina, the build instructions for the 540 and what you guys have done.

 

The following is the Foamy Dave's Ballerina as built by me

 

The all up weight is 202g. Span 700mm, wing area 13.3cm^2, wing loading 15grm per dm^2.

 

Compared with the 540, span 920, wing area 17cm^2, wing loading 18.3 grm per m^2.

 

I have also been looking at the construction methods, used by the two designers.

 

a)   Foamy Dave (FD) uses UHU Por to attach CF to foam, where as tape appears to be the principle adhesive for the 540.

b)   For hinging, FD, uses Blenderm, rather than the re-enforced tape supplied for the 540.

c)   FD used CF push rods against the wire supplied in the kit

d) the Motor Fd used a Blue wonder which weights 20g against the 39g of the CF 2805 or CF 2822.

 

Trying to get a grip or more accurately a ball park weight, 4*5g servo = 20gram, using a Lipo @ 45gram, a motor @ 20gram, 20A speed controller @ 20gram. Rx @10gram. The total would be 215 gram as a minimum.

 

I am considering placing the CF wing stiffener, in a slot, cut into the wing, securing with POR.

 

I have not weighed as yet the metal push rods, but am considering replacing them with 1.5mm dia, CF rod as per FD.

 

Also I suspect these horns would be lighter or these?

 

At the moment I am seriously tempted to minimise my use of the tape supplied, with a view to saving weight.

 

It is not clear to me if the 100 gram, is all the contents of the kit, or just the foam, does anybody know?

 

I am aiming to get the weight near to the 300 gram level, as it is easy for the weight to escalate.

 

What would you have done differently?

Edited By Erfolg on 03/11/2010 13:39:59

[Bob Moore]

Looks like a fun model.

 

100 gms is the weight of the foam with the Edge . GC say 310 gms with battery?

 

I used Uhu Por to glue the depron,

 

My weight came out at about 400 gms.

[Stephen Jones]

Hmmm wot would i have done differently ,

Well in hindsight i think that, i `d had the right idea with only using one servo for the ailerons , as this not only saved weight but also less drag . Also fitting the flat cf into the middle of the wing .

However the model was very floppy but if i had of added a little extra depron around the motor mount and made a triangle boxed section along the under side of the fuselage running from the front to the back this would of added the extra strength and covers the servos reducing more drag . Then i would off added strong cotton thread to help brace the wings to the fuselage .

I still have a Cap 232 un-built which i may build in this way .

 

I used clear packing tape for the hinges and a combination of foam safe ca and deluxe materials cockpit glue which i use a lot as it dries clear and is flexible but strong , only down side it takes half an hour to dry, but does allow you time to reposition .  

[Bob Moore]

I agree about the flat carbon. Too wide for a leading edge.  I used a round bit of carbon stuff for the leading edge. The one servo for the ailerons was indeed a good idea.  I too found it very 'floppy' , esp at the back end, so I glued some triangular balsa along the rear fusi to stiffen it. It worked well and didn't add much weight.

 

I offset/spaced out,  the rear two servos as I thought it would create a weak spot to put them so close together?

Edited By Bob Moore on 03/11/2010 21:25:41

[Erfolg]

What has surprised me is the difference in all up weight.

 

Foamy Daves models all came ot at 170g. My own build was 20% over his build/target weight.

 

I suspect that the amount of Depron in the Ballerina and the 540 will be similar. Due to the Ballerina being a biplane.

 

Yet the difference in finished weight is enormous 202g against 400g for the heaviest example of 540.

 

Could the difference be in the details. I followed FD methods as much as possible. As mentioned, FD used CF for the push rods. The UC is mainly CF. The control horns minimal plastic horn, connected using heat shrink. It could be that using a smaller 2s lipo and a motor at half the weight, helped a lot.

 

I will try and access how much weight can be saved with a minimalist power train.

 

The Ballerina flies extremely well (pity I cannot control it) and I suspect it is the light weight which helps. It seems to help with both crash and arrival resistance.

 

Do you think the slot idea is viable, in both reducing weight, a cleaner installation aerodynamically and a better physical arrangement?

 

Have you had time to consider your models relative to the build and flying experience.

 

 

[Erfolg]

Bob

 

Can you post a picture which shows how you installed your aileron servo. I cannot quite work out how it has been done, from the posted pictures.

 

With the Ballerina it is easy, as it sits underneath the model, where it is vulnerable and needs the UC to help protect it.  On the plus side there is no reduction in the Fuz strength.

[Bob Moore]

I think the instruction said put the aileron servos underneath the wing?  I mounted them on top and at a place where they are through two thicknesses of Depron.  Offset so that they would push pull the horn at 90 degs. On the underside I glued small bits of balsa and the servos are pushed in and screwed rather than glued, so I can use them again.  I mounted the rudder and elevator servos differently as well. Offset.  Also with small balsa backing plates.

 

The original battery support was unusable, so I changed it. The battery leads go up through the wing to connect to the speed controller above.

 

I didn't get the u/c right as didn't understand the instructions, but it's Ok and as you don't really land on it (just plop it on the long grass) it's serves it's purpose.

 

You can see my triangular balsa stiffener along the rear of the fusi.  It's possibly a very little heavier but quite a good stiff little model.

 

upper surface of wing.

 

 

 

 

[Erfolg]

Sorry Bob

 

It is Stephens aileron installation that I would like a picture of!

[Bob Moore]

No worries. 

I quite like having two. Gives more ease of adjustment? Certainly makes a better angle with the horns.

Edited By Bob Moore on 04/11/2010 11:10:24

[Stephen Jones]

Hi Erfolg,

 

I have already posted pictures of the aileron servo from top and bottom , is it a side view you would like  

[Erfolg]

Yes Stephen,

 

So I undersatnd how much material it is necessary to remove and  to insert etc.

[Stephen Jones]

Hi Erfolg,

 

 

Excuse the worktop these pictures are  a bit rushed , i have put more in my album and have taken more of the rest of the plane if needed . I must confess i don`t like the way servo leads and receiver are surfaced mounted .

As i mentioned earlier i built this one first as it was damaged on arrival , although it suffered further damage due to the receiver lead from the Esc not being plugged fully home .    

Edited By Stephen Jones on 04/11/2010 20:40:30

[Bob Moore]

Finally found the best prop for my set up.   A 9 x 6 GC slowfly prop.  It now draws 9 amps (as opposed to 6 or 7 with previous props) and climb is good.  Flies well at half throttle.

 

It sure is a handful in anything other than a gentle breeze, but great fun.  Almost more balsa holding it together than depron now after one or two mishaps. Including losing control after flying in too strong a wind, and losing a prop mid flight.

[Erfolg]

Today I have started on my 540.

 

The reason is that my recent Internet purchase policy has been a failure, loosing some items and realizing i have purchased some others, on what looks like a long delivery. This has stopped two ongoing projects, stone dead in the tracks, until life can be breathed into them again. Which were nearing completion. Dam! Such incompetence, Ahhhhhhhhh.

 

Anyway, the 540 seems a lot flimsier than the Foamie Daves Ballerina. There being far more stiffness in the FD body due to fillets and nose reinforcements. Also the wing arrangements are stiffer and possibly more robust on FD design.

 

I have started by gluing the body parts together.

Edited By Erfolg on 28/12/2010 12:42:02

[Bob Moore]

It certainly is very flimsy. Mine has had so much balsa and tape added for repairs after almost every flight that I have had to move the battery forward to achieve a satisfactory CoG.

 

I have managed to take off on the wheels on very flat ground,  (dirt track) but find it safest to drop the model into long grass when landing.  The elevator is very fragile, and even dropping into bracken managed to snap the foam. (Take a roll of tape with you when you fly it.)

 

Prop saver essential to. I broke the motor out of it's flimsy foam mount on the first flight. The front end was then reinforced with balsa and I had no probs since.

 

Having said how flimsy it is, in light conditions it's great fun to fly. I have more or less cracked inverted flying with it. (With no worry about crashing a £14 model.) I'd say it's one of my favourite models? 

 

Look forward to hearing how you get on with it.

Edited By Bob Moore on 28/12/2010 13:02:36

Edited By Bob Moore on 28/12/2010 13:04:14

[Erfolg]

As with most simple mods, they are not as simple to implement as envisaged.

 

I have started with full length body fillets, on the underside. My next set of fillets is on the top on just the nose area.

 

The problems already are the wing tailplane and uc plates, none of these have been done.

 

If you see the indoor event thread, you will read that FD says the models are now down in the low 100g. A lot of this must be down to materials and how they are used. Viewing the videos, it is apparent that these guys do not crash as frequently, or with the panache I achieve, world class is inadvertently reached from time to time.

[Erfolg]

I have read the instructions, a number of times now, but where is it? The CG, I can not find any reference!

[Erfolg]

I have now worked on the wing and completed the nose re-enforcements. I have inset the spar rather than surface mounting, as per the instructions.

 

I have attached FD link here to show how weight reduction really does improve performance. Plus how they can be flown, rather than how I try and fly link.

[Stephen Jones]

Hi Erfolg ,

 

Yes weight reduction really does improve performance. 

 

But we have the GC models so we will have to move the radio gear around to get the weight and balance right which is not shown .and add extra strength to keep it rigged .

 

I have bought one that is made out of epp which cost twice as much and comes with lots of carbon fibre and shows how to add to keep it all rigged but helps keep the weight down wots more it shows you where the CoG should be  .

So what do i do now with the extra that doesn't fly right as it is to tail heavy and the un built cap 232 i got from GC  .   

Any way iam going to do some more work on my Sipa 200 now .

[Erfolg]

I am tempted to start with 30% of the mean chord, ignoring the keel area, although this is substantial. At face value the keel area should allow a CG further back, so I guess 30% is prudent?

 

I have made more progress on the construction, which is not to difficult with this type of model. It is my illness which is now limiting, now taking penicillin, due to secondary infection. Them bug ridden grandchildren.

 

Erfolg the Grumpy

[Bob Moore]

By some calculation from this thread, my CoG (using a graphical method in the end) is about 8 cms from the leading edge. I had it too far aft at first and was having to apply masses of down elevator for level flight, but then found it wouldn't fly inverted  (which I have been teaching myself.)  Now I've got it about right, it  flies ok inverted and trims easily.

 

I also put fillets (triangular balsa?) along the fusi as it was way too flexible. And a lot more balsa here and there after a few mishaps.  Even dropping it gently into some brambles damaged the elevator? 

 

And I fitted the carbon rod spar along the leading edge.  Better airflow I think, and it gives the leading edge some protection.

 

That's a very impressive video of the nationals. I can't get my Edge to prop hang  (not sure if I'm able to do it either!)  I'll be interested to hear what motor /prop/battery combi you use.

 

Hope you get rid of the bug soon.  

[CARBON_ROD]

  Each to their own ! But to me it looks horrifying and £13 ? ok leave you too it .TD