Rate1

I flew my Extra for the first time for this season today. I liked it.

a340

That looks great Rate1, nice colour scheme.

Gonna have to carry on with mine, all built and has been for a couple of years now, just needs the covering. It will be powered by an OS91fx.

Leigh.

Rate1

...well get cracking with it. You will not regret it as I am sure you are going to love this plane.

You guys that have finished building and flown this kit, write your comments about it under Airplane Reviews.

C.

TheMachinist

This is a great thread! I have been a member here for a while but I was mainly involved with RC trucks. I ditched all that stuff and started flying. I am still learning with my 40 trainer. But I needed something to work on so I started building one of these 60 size extras. I don't plan on being able to fly it until next summer even if it was finished tommorow. I am building it completely stock except for some things that I read about here, but nothing involving the control surfaces.

What do you guys build your wings on? I made a table for most of the work that is completely flat. For the wings though I wanted something that would let me push a pin into it.
so I put a ceiling tile on top of my flat surface and started building the wing. The tile seems like it might flex a little bit and that worries me. Also what can be done about an assembly like the rear stab warping slightly after I built it? It went together straight and lined up with the drawing perfectly, after it sat for a week it had bowed a little. when I put a straightedge across it there was a 1/32 gap in the center. Is this normal?

Sorry about the plethora of questions, maybe I will be able to help some one in another area!

jb86

My Feedback: (8)

the "warped" horizontal; is it sheeted yet? if not, then glue the sheeting on w/ca on a flat surface, that will straighten it out. otherwise, if there is a small bow place it so the tips point up (not down).
you have to know that a scale aerobat (extra, edge, ect) you have to be careful with take off, landing and slow flight. most important thing you can do to keep it tame is to keep the weight down, everything i've read on these threads is, try for 7 1/2-8 lb. saito 100 is about the best engine choice. there is a great thread called something like "great planes extra 300 build/mods." i think his name is adrian. the modifications are worthwhile and not dificult. there are lot's of great tips in his thread.
my extra is almost done, covering complete, just assembling, but i can't touch it for a few months. i have an os 120 fs w/pump, very heavy, but i have it. comes in at 8 1/2 lb. and to get that i used lightweight equipment any where i could, saving about 7 oz. w/ the os 120, i put the two mini elev. servo and the mg rudder servo in the tail to balance.
this probably isn't the best choice for a second plane. you should get something a bit more forgiving. i think a fun fly like the ucando .46 is a great choice, i fly w/a os 70. it gives you a chance to expand your flight envelope, definitely get some inverted practice.
as far as a building surface, makes sure it's flat. i use a particle board (called hdo countertop substrate) about 2'x4', i lay it on top of the building table, check to be sure that this is perfectly flat and not warped, a 4 foot level placed criss cross to the opposite corners, and lengthwise.
place the plans on this board. i never cared for pinning the spar down, it slides around. i use (4) or (5) 1/8" plywood pcs, about 3/4" wide and 1 1/2" long, drill two holes in them and use dry wall screws into the particle board, to clamp the spar down. keep them straight w/ the line on the plan, and adjust w/a screwdriver as needed. this way the spar is held tightly. be sure to put great planes plan protector over your plans.
jon b

Rate1

Make sure you do increase rudder area. You will need it since original design does not have big enough for good knife edge. With my OS120 it came into 8,3 lbs and flew very nice. Landings were nice and slow never snaped on me. I used good std dual servos for elevator and for the ailerons. A mini servo för throttle and a strong digital on the rudder. Otherwise, as said, build it light and you will love it.

Captain Randy

My Feedback: (1)

I built mine with stock rudder and stab./elev. With an OS FS 1.20 it has more than enough rudder to knife edge. You just need a good servo. The mods for this plane are just for looks. I would not recommend this as a second airplane. Get a stick or a Four Star.

rcapmd

Machinist:

RE) Building Board - Relatively cheap and by far the most reliable I've had to date.

Fortunately I have a glass company on my block - had them cut me approx. 1/4 inch thick, 24" x 48" glass slab - ($50.00) Slap a piece of sheet rock/drywall on it ($5.00) to pin into and your good to go - straight and flat as can be. Never a problem, no worries about eventual warping etc. After a couple builds, simply replace the sheet rock.

regards -

jamesflies

Hey guys im finishing up my extra, i am planning on using a super tigre G-2300. is that overkill? its only a couple ounces heavier than the o.s 1.20 without the pump. and there is always the throttle stick, so tell me what you guys think. i did mount two elevator and one rudder servo in aft end of the fuse, so balance shouldnt be too big of an issue.

thanks,
James

flapper

James,
I would recommend beefing up the engine box. Probably look at using fibreglass and epoxy to ensure a stronger fixing of the box to the front former. Might need to make the actual firewall thicker to improve the joining surface area on all four sides. It is only light 3mm ply used for the engine box.

jb86

My Feedback: (8)

weight is a major concern, the os 120 fs is a bit heavy for the aircraft, it raises the auw to 8 lbs. read thru the thread "GP extra 300 build mods." he used a saito 100, best power/weight. too much weight and power w/a big prop makes it too easy to snap out of control. you have to keep the ailer and elev deflection really low at low speed. worth reading thru that thread, alot of good info.
jon b

Rate1

Just to conclude my Extra.
I have crashed it by misjudging the distance to the treeline while flying in the dusk. I am kicking myself for this as I am aware of the danger of lost perseption of distance while flying in such conditions (I am a full scale pilot). However, the plane is far beond repair but thankfully the engine and all the electronics made it.

I used OS 120 Surpass III pumped and found it an excellent choise for this kit. Landings where nice and slow with no tip stalling tendencies, speed was good using a APC 16x6 prop that also offered good breaking during downlines. Stall was soft and straight, totally uneventfull with no tip stalling. Had made enlarged rudder and elevators which almost gave me knife edge loops (never had the guts to go all the way around). Had dual tail mounted elevator servos to counter the rather heavy swiss watch like ticking engine with an awesome sound. No lead was added to achive balance (used 0,5 oz at left wing tip for lateral balance to counter side mounted engine). For rudder I used a strong digital servo, micro servo for throttle, carbinote geared servos for aileron and elevator. All servos where Hitech. Knife edge to hover was posible. Further, I had nice selected hardware such as DP Ultimate tail wheel ect. Tank was c of g mounted = no triming throughout the flight.

The total weight of the plane was 8,3 lbs. Hover was acomplished at approx 1/2- 3/5 throttle. Not knowing if power curve was linear but I would guess power to weight ration was parhaps 1:1,8 (that is almost twice as much power as models weight) when using 15% synthetic oil and 15% nitro (never got time to try 30% nitro). Vertical performance was not rocket but with authority and to out of sight. This was not, as many is aware of, a 3D plane but a VERY good traditional aerobat. I found this plane very stable and predictive hence very easy to fly as it did all I asked for and nothing I did not.

Having all this said I should meantion that I used it as my trainer and it was my very fist model aircraft. (Beside being a pilot I cheated by taking training sessions on club trainer and flew rc sim for 6 months before flying this Extra). I loved that plane and are feeling a sence of pride that I manage to acomplish such a nice plane especially being my first rc plane ever and recived compliments from people that though is was a very nice ARF (I recived a lot of helpfull tips building it thru this RCU thread).

The good part of this story is that apart of all the gained experience this have given me; learning to building, triming, flying, selecting hardware, and overall rc skills, I will now enjoy the next project. [>:]

Regards,

C.

jb86

My Feedback: (8)

sorry to hear about your extra. i thank you for the discussions and listing your included equipment. i haven't touched my extra for about 4 months. i have it covered, all control surfaces are hinged, just finishing the equipment installation. i have the same os 120 pumped engine, and similar set up w/servos. i did a mock up before covering to check the approx cg, anticipating needing tail weight w/the 35 oz. engine. AUW comes in at 8 1/2 lb. i got to get it done soon, i'll post pic's. again sorry for you crash, however, your posts have been helpful. best of luck.
jon b

Rate1

jb86,

I am looking forward to read your flight report and perhaps see a picture of your Extra while airborn.
Exciting times for you to come and I am sure you will love your plane.

Good luck,

C.

Captain Randy

My Feedback: (1)

Rate 1

Sorry for your loss. I agree this is an awsome plane, but it still left me wanting to explore areas that this plane could not perform. After my GP Extra 300 experience. I went with a 28% Wild Hare Edge with a 50cc gas engine. It's relatively cheap, good customer support, and flies better than the GP Extra. By better I mean it is easier to fly and can do everything in the book.

Just offering a suggestion..........

Rate1

John Deer,
Thank you for your suggestion. I will have a closer look at it. For now I am investigation diff German made Extra 300's that might fit my OS 120. A bit more expensive and exclusive it appeare but still not knowing if that also means better??? Regardless I am past mourning my love and joy and are now looking forward to my new project.

Regards,

C.

jb86

My Feedback: (8)

goldberg has a (new) nice looking edge 540, 67" wing for the 120 4 stroke. a nice feature is the 2 pc wing. stated at 9 lbs. an arf for about $350. that would be my next choice for this engine if i didn't have the gp extra 300. i don't want anymore 1 pc wings for transporting. i actually considered if i were to build another one of these, to recut the fuse sides, and change the wing to a 2 pc wing w/sockets in the wing and an alum tube.
jon b

Rate1

Yup I have looke at the CG Edge. There is a thread on RCU about it and apparently it is a blast to fly with the OS 120 4-stroke.

delphichenbin

My Feedback: (1)

This is mine, just finished the fuselage and covered it yesterday, did half of the wing, hopefully, finish all this month.

alfredbmor

I like the way Adrian enlarged the Rudder and shortened the vertical fin, as for elevators I did not get a clear idea, my Extra is still in Tower Hobbies and I expect it for the next week, I have time to make things right.
I really like the Adrian's maiden flight post, and is the main reason that leaded me to buy this kit.
Happy landings.

AdrianM

My Extra was a superb flying plane. It was not a 3D plane and it was not a Pattern plane but it could do a lot of both. If I were to build mine again I would use a new Saito 125 or a YS110FZ. I ran my Saito 100 with a 15x6 and a 14x8 on 30% very hard to get the power I wanted.

I would also redo the rudder with smaller square sticks so I could sheet both sides with 1/16" balsa for more stiffness. My modified rudder was a little flexy but it flew just fine.

With the Saito 100 over the course of 2 months flying I added 2oz of lead to the tail. If you are going to use a heavier engine move the rudder and elevator servo to the tail.

I would also join the two elevator halves with a 1/8" wire joiner so I could run one servo to control both elevators.

Hmm...maybe its time to build another one

I quit flying for a while and I gave this model to an awesome local teenage pilot that that flys the heck out of it and really values the time I put into it.

a340

Well I have finally finished the covering on mine, just need to set the CG which I have found to be very nose heavy. It has an OS91fx with a BCM pitts style exhaust. Not sure on the AUW yet, maiden flight in a couple of weeks hopefully.

alfredbmor

I hope you'll be back to the shop soon, what are your thoughts about the rudder update that you did. Performance increased?. Adrian thanks for your answers.

sctstone

This is a great thread. Ive just finished covering mine though I will be adding pin stripes along the joints of the two colours. O.S. 91fx, yet to add servos though I will join elevator halves. Interested to see how cog turns out.

Captain Randy

My Feedback: (1)

I blacked out my canopy and it warped bad after five minutes in the sun. Just a warning.