hi - I built the .40 size extra 300 from Great Planes - see pic below

I am pretty happy with it except I cannot get it to flat spin...

I tried, starting from regular spins, both upright and inverted, and what happens is when I decrease the ailerons and start making them opposite to the rotation, the spinning stops. I expected it to flatten and keep spinning... I already read the threads about flat spins but I still can't do it ... Does anybody have the same aircraft and manage to have it flat spin? I need help with the sequence of control inputs, maybe CG location and control throws too...

thanks

I followed the instructions except I replaced most of the sheetings with thinner and lighter balsawood. I can't remember the weight (built it several years ago) but it's pretty light. The engine is a .46fx OS, and with 0% nitro and a 12x6 graupner prop, the thrust is greater than the weight of the aircraft, I get unlimited verticals. I can also get it to make 3/4 of a knife edge loop, which is pretty nice... Only the last part (the downward->horizontal part) fails. It is a very nice airplane, I just need fine tuning to make the most of it.

Hi!

Mine is ASP .80 FS powered, and also very light (2280g dry ready to fly) due to material selections and a few extras like fiberglass cowl and a carbon-fibre landing gear.

It is an awesome setup with more than unlimited vertical, hovering is nice (bigger rudder would be helpful here), torque rolls possible, but hard to do...

It is a great flyer, but mine also doesn't like flatspins - normal or inverted. I tried several CG positions, one setup way waaay to sensitive, but it didn't flatspin. When I tend to flatten the spin (feeding ailerons in opposite direction) out it starts to spin slower and that's it. Those spins are slow, but not flat. It takes two normal spins for the height-loss of one of these "flat" spins.

As far as knife edge loops - as it seems I have to install more powerfull servo on my rudder. Which servo do you use? It helped a lot using a five-cell Rx pack, but all I get is some 30 deg knife-edge climb (Futaba S-3001 servo).

It took me some 30 flights to really get to know this Extra, but after 90 flights all I can say is : very nice little airplane. It is a superb flyer, very pattern like. I just have to upgrade the rudder servo to be able to make more out of it...

Sašo

Mine won't flat spin either, it just doesn't have a big enough elevator. Other than that, it is a really great plane.

Have you guys tryed to enter the flat spin like a blender????
point it down and give it full ail.....wait for about 2 rolls and then give it the spin cammand. Makes it a little more violent but should get the tail down. Hope this helps.

Nope, doesn't do anything. Just really ugly negative snaps. You need a big elevator with lots of throw to get a plane to flat spin, the Extra 40 just doens't seem to want to do it.

Think this is big enough???

That is the elevator for the 300 im building. I moved the hinge line 1/2 inch up and added about an inch to the elevator.

guys, thanks for the replies

so it seems there's no way I can get this a/c to flat spin as it is.
I might build a larger rudder and elevator. Or first i'll try to tape cardoard to enlarge the control surfaces, then if it proves better i'll build larger surfaces.

frcac - my rudder servo is graupner (JR) C5007, which is a $20 servo, just a bit stronger than bottom end of the market. I run it on 5 cells NiMh. I can try to find more info of the servo (torque etc...) if you need. from what I see it's a bit bigger and heavier than my 3001s

also, what CG location did you retain at the end?

hi there
i have the G.P extra 300s with an o.s 46 fx
what prop should i use with that engine on this plane?
and i am using 5% nitro do you think i should try some 10%?

thank you
roy

An 11x6 should work well with this plane. I'd just try it with the 5%, then if you want a little more power give 10% a shot.

I like the 11x5 wood on the fx. Iv run that prop and motor on a couple of planes and i allways go back to that prop.

capnic: hm, that Graupner C-5007 has almost identical torque. It might help you with that last quarter of knife edge looping if you installed C-5077 (5.5kg versus 3.5kg).

I will check the CG location and will get back to you. Where do you have your CG?

As far as props are concerned - 11x5 will make the most out of OS .46 FX. If you use higher nitro content (15% and above) try 11x6 - thrust difference is very obvious.

Sašo

You can get it to flat spin, but you'll need to move the CG aft, and get more thow on the rudder. You'll need to eliminate some of the flat-plate area of the vertical tail.

By the time you get done, it will flat spin, but may not recover. These changes will work with almost any model.

I have a Great Planes Trainer 20 with the CG a bit aft, and it flat spins beautifully....right into the ground! Landed straight down on the gear and cracked the fuselage badly! A lot of CA glue, and it was flying again.

Man I hope mine pulls out of spins!!!!

I have the 300 to. Mine is powered by a saito 80 and will flat spin, blender, knife edge loop all day long WITH ONLY THE LEFT STICK!!!!!! and will even torque roll When I have good day but the right prop helps to. Although i am only 17 I am by no meens an amature although my spelling could use some help. I have had to do some signifigant changes to the model. I redesigned the rudder for NO ROLL OR ANY COUPLING just about doubling the size of the rudder with lots of throw on it. If anybody would like the planes for the rudder I can e-mail them to you. I put an extra inch on the elevaor and hinged it with about 75 degree throw and always make everything lighter!!! The only disadvantage with this model is the weight. And talk about harrier? What harrier although it works more when inverted. I will probably take the saito out and put in an os 91. If anyone has the thrust of this engine I would love to know. I bought this plane to see if I could 3d a 40 and I can.

[email protected] did the same thing im doing....COOL!!!!

What does your plane wiegh??What motor are you running?? This is what i wanted to hear. I know the plane can 3D if the bigger ones do. Just need to change a few things. Check the pics out and let me know if im on the right track?? What about walls, or does it snap out?? Have you tried waterfalls yet?? Does the plane still fly with a little presicion?? Im hoping for a imac/3D plane. Thanks for the info!!!

can'tfly@all, you caught my interest!

about your elevator: you made the control surface wider by an inch, was it all along the entire span? Did you also move the hinge line forward to reduce the stabilizer area?

about the rudder - to eliminate roll coupling, did you reduce the height of it and put more width at the bottom, as on cap 232s ? and just how wide is it at the bottom ? at the top ? did you move forward the hinge line?

what do you mean by "... always make everything lighter!!! The only disadvantage with this model is the weight. " did you mean that building it per the instructions makes it too heavy for 3D ? How much does yours weigh ?

I can already see that people are interested in what I do. This is very must the same reaction I get at the field. I enjoy buying a plane that people already have and flying it better (WITH MODS), I know its mean but its fun. To start with the questions I don't know what my plane weighs but I can tell its to much It would be able to 3d without mods if it were lighter. Da king I think that your elivator looks good try it because you can always go bigger. And Walls are doable but dangerious the third flight a gave one a try and broke the stabilizer the only thing holding it on was the monokote. Luckily I was able to get it down without a problem. So I put fling wires on it and haven't had a problem. Da king what engine are you going with it better be big! This bird is TAILHEAVY.
Capnic The elevator was crazy and alot of work I moved the stabalizer forward added an inch along the entire span and on the sides of the stabalizor has the elivator to WATCH THE FLUTTER. Rudder I added about two inches to the top (TALL) and about 4 inches to the bottom (WIDE) But the shap stays the same. I will try to get som pics but no digital or scanner If you want I can make a diagram in paint shop and send it two you with the dimensions. And last the weight on this plane is bad so lighten it or else. Any answers to My question???????????

I havnt seen any thrust numbers on the 91 but a lot of poeple dont like it. They say its not what its supposta be.
[email protected] running a os 50sx. BUT...I changed the wood in the wing and lost a LOT of wieght. Allso will be carving out the fuse and changing some wood to lose sommore. I think i will put some carbon in the tail. Maybe some wires too. Your rudder and mine are the same thing but i moved the hinge line 1/2 inch. I didnt add any width to the elevator though. I thought 22 inchs was enough. hehe.Also cut a 45 deg angle on the elevator for the rudder. you need to wiegh that thing. The lowest ive seen is 5.5. mine should be in the 4.5 to 5 lbs range. I hope.

This plane would be perfect if the weight could be 4.5 - 5 anything heavier then that is to much for 3d. But It can be done its just harder to do. yours will probably come out tail heavy with that engine I have a saito 80 and 2 oz of lead in teh front of the thing. YA you need to cut the elivator to get the trow on the rudder you need. I weighed it on a friends scale I dont know how (on) it is but it said 5.75. The os may be lacking in power but you can always put in a bigger one.

I did cut the elevator for 45 deg throw. I plan on taking wieght out of the tail and the nose too. a lot of it will be out of the tail. I think i know why it tail heavy so i will fix that when i get to the fuse. I just sheeted the wings so all i have to do is join them and then i can start on the fuse. HERE COME THE DRAMEL!!!!
hehehe.