I can't remember the size fuel tank that came with it since I made mine into a twin with twin 4 ounce tanks in the engine nacelles. The tank that comes with the plane is probably around 6 ounces.

I played around with the pushrod installation and found a configuration that required no bends. Here are some pictures. I don't have a throttle servo in the fuselage, so the install will have to be different.

The MDS .40 most likely will not fit and will be way too heavy for the nose. The O.S. LA .46 isn't really a true .46, more like a beefy .36 the plane is rated for .25-.32 but I dropped a LA .46 into mine with no problem (well maybe I did have to spread the mount very little to pop it in. and I mean very little) and get this, I had to put the rx battery and the rx right on top of the battery (which I guess when it's right side up the battery is on top the rx and right behind the tank(basically where they show you to put it) because it was tail heavy, even with that LA .46.

The link setup was the hardest part in building this plane. Make sure you install the aileron servo with the output shaft toward the leading edge of the main wing(I put it in the wrong way and it would not clear the throttle servo) also use lock tite on those ez links connectors they use on the throttle and steering servo arms. They use a nut on the bottom instead of a locking collor(mine came off, story on that in a sec) I did have to bend the elevator push rod where it exits out the AFT end of the fuse, so it was more in line with the horn on the elevator. The rudder lines up better and doesn't really need as much bending.

The pictures suck as far as for the link setup in the manual and can confuse someone whose hasn't put together many planes yet, when it comes to setting up the links. When looking down at the fuse while it is upside down and nose toward you. The rear servo tray will have the elevator on your right with output shaft toward rear, cut all arms off except one (duh) and have it toward the wall, it's push rod will exit out the AFT right side and connect to the elevator horn (with bending, and some time trying to get it to exit out threw the cut out in the AFT section). The rudder/steering servo will be in the left tray with the output shaft toward the front of the fuse. The steering link will be the wall side and the rudder is the inner side of the arm. Push rod exits out the left AFT section of the fuse. The throttle servo is in the front tray with output shaft toward right side, remember the locktite if you use those ez connectors they give you.

I left mine as a stock sonic with the tri-cycle setup. Take off was fast and easy and was airborn with the OS LA .46 running a little rich to finish what little break in this engine needs. Just needed one touch of aileron right trim.

Did I tell you I got the sonic and OS LA .46 for $100.00 at the LHS

Anyway. I did some passes, then stall tested it, it doesn't tip stall (although maybe if the elevator travel is way up it will tip stall/snap). will pitch forward quick and go into a dive, with no power you may have to dive about 10-15 feet to build up flying speed again, throttle up and your pulling out of the stall no problem. Slow flight is stable, doesn't really rock on it's wing. Rolls look nice and slow, practice using down elevator and up elevator as it rolls to keep level flight. Inverted pass down the runway (did my first low one or I should say lower one maybe about 10 feet with it) upside down you have to start holding down elevator to keep the nose up (remember we are upside down right now) to keep it from diving too much. The inverted pass was sweet looking.

Landing is easy but you have to have a far approach if there is no wind to slow you down, remember it's a thin airfoil so it will keep up speed longer than a high wing trainer with a thicker airfoil. I bounced it once or twice and the gears handled it.

Now for the crash test. This wasn't good, I was practicing touch and goes and on one of them the engine didn't throttle up fully as this happen I was trying to blast off vertical because the .46 LA will pull it unlimited vertical (I did it a couple times) well that time it stall about 18 feet up and right in front of me. I stepped back as it stall and it swung toward me (it was trying to kill me I think) it pitched down and shot passed me and I knew it was going toward ground I pulled back at the last seconded to land on the prop breaking it off and get this, it bent the main nose gear almost all the way back but didn't rip the main gear mount off the firewall nor did it crack the firewall. It was all intact and would of flown again after replacing the prop but found that the throttle servo wasn't moving the throttle so I opened it up to find that the ez connector came off the servo arm and the nut that holds it on was inside the main wing because it feel threw the aileron servo tray because I didn't use locktite and this is also the first time I've seen threaded and a nut used, usually it's a snap keeper that holds them on. Once thats set it will fly again.

Other than using the OS LA .46 I say the sonic is a sweet forgiving flier in the stock setup and recommended control throws. The tank gives me about 10-12 Min's and is maybe a 6-8oz tank. I had a lot of fun with it at the field and look forward to flying it again. I started with the Alpha trainer then the Ultra stick 60 and say the sonic is easy to fly and makes a great low wing trainer, maybe even easier to fly then the ultra stick 60.

Hope this helps

Hey Jbird

Thanks for the really good info there. Any chance of some pics??

I designed nad made myself a new one piece engine mount that fits into the stock firewall holes and accepts my MDS 40 no probs. I wanted to use this MDS as it has been lying around for many months now. All my other engines are much larger. The next size up I have is a GMS .47 which is going into a GP Ultimate Bipe which I will be building soon. So the MDS had to go in. I have also mounted it as far back as possible for better weight distribution. I'll have to wait and see when it comes to balancing.

I finished the mount yesterday and put it in last night. Works a treat. Will hopefully be finishing it all up today, just need to get some threaded rods from my LHS as the one of the ones that came with the plane broke when I tried to make a z-bend in it using the GP z-bend pliers???[:@]

I will post some pics later this afternoon when it's all done to show the engine mount.

Cheers

Luis

Just made the first flight this afternoon! Unfortunately, it was windy when I first got to the field, which caused for a horrible first landing, and decided to rip off the front gear (tail dragger)...nothing bad, just screwed it back on, and 5 mins later it was up in the air again....lets see, as my second plane, this thing is AWESOME. just what i was looking for - I have a LA 46 up front which makes this thing MOVE, plus, what seems to be unlimited vertical. Luckily, the plane is easy to fly, landings are faster then a trainer, but WOW, I made my best landings ever (minus the first, wind shear impacted landing). I am 100% please with this plane, and would suggest it to anyone as a daily flyer/sport beater - or a nice step up from a high wing plane. At $75USD, you can gain low wing confidence without breaking the bank. I have a Sig somethin' extra just waiting for the first flight - I think it will be very soon.

i will be puting my 46FX (vertical flight, wooh) will be going in mine. Thats if i can decide between the ultra stick or the sonic

I have one as well great little flying plane... I am running a OS FX 25 on mine now.. I started with a OX 46 FX WAY TO MUCH Weight made the plane heavy and landings fast... When I went to the FX 25 it is the perfect power... Smooth Cuban eights not a problem... Out side loops... You name it... Reminds me a small Kaos..

My suggestion use a FX 25 on this plane... It is the perfect combo. Plently of power and makes the plane light... Look at the specs on the FX 25

25 FX (OSMG0525) CU 0.249 0.710 0.630 RPM 2,500-18,000 BHP 0.84 @ 18,000 8.8 oz

You go with a 40 or 46 you end up adding a 6-10oz to the plane... Yep and a half pound makes your engine size gain not such a gain....

It's an airplane and lighter is always better...

I ran with the O.S. .46 LA and had to get the battery pack and the receiver as far up as I could in the compartment.

Sucker moves :-D remember you can always throttle back if it's too much

The OS LA 46 is only 9.6 ouces... pretty good match as well.

-Steve

True... I just like to use mine for Aerobatic stuff... If you want speed... I promise ya when I had that FX 46 in there it hauled tail, big time, did you beef you fuselage up, I added some wood triangles to the back of the firewall just to be sure with the 46... With the 46 on it would have probably made a good pylon racer... But with 25 she is whole lot lighter, and is a real joy to take for a aerobatic fly... And still lots of power mind you... Supurised me... till I found out that OS 25 FX I have on it, has about the same power as a LA 40.

Yea I bet it does do well with the 46 la... I was just looking and you are right on a oz or so differance... I was running a FX which is quite a bit heaver then the LA 46... Looks like the power on the LA 46 is 1.2 so you are getting about .3 more hp for an oz of weight... Not a bad tradeoff... I have you on one thing though... "Economy" I get great fuel milage out of it... 20+ minute flights...

Have fun... I really do like this little plane.. Real versital and soild made... And well under a 100.00

I agree with electron. I had a 25FX in mine also and it was more than enough power for this plane. It just doesn't seem right that an airplane would perform nicely with the recommended power plant. Electron also stated it correctly "it's an airplane and lighter is always better".
bdb

I just took my sonic up for the second time and had just made changes to the cg. Boy was I off!! I ended up having to bury it into a cornfield so not to hit anything! Dam its a tuff plane, just did some checks, removed wieghts from front and up and away again. I dont understand how to balance this thing accurately! Every time I check balance it seems different. Can u not use the 2 person fingers on this plane?? Im using a os40la also. This is a very fun plane to fly!
Tim

Should not be a problem to use the two fingers as a CG balancer, thats how I did mine... Are you checking without fuel then with fuel, because the CG shouldn't change...


You want the plane to balance at the CG point or even 1/4" nose heavy is good...

it's a low wing, so you have to balance it upside down


Jeremy

I balanced it upside down and flew it again last night. God I like this plane. Touch and goes are a blast! Thanks for the help guys, it was right on after i balanced it upside down (my first low wing plane). Tim