thanosg2004

Lee,
thanks very much for your reply.
I have one more question : Do you think that with the OS120 fs pump in front and with 2 elevator servos aft
the model will be tailheavy ?
I will keep you all up to date and post pics as soon as I start building it. ( Cant wait to start But have to wait courier ).
I live in Greece so I have to wait a little untill the kit arrives at my door. Goldberg's models are very popular here in Greece even if there is no distributor and we have to order from US and pay courier cost too ( 80 $ for this one ).

Thanks again for your reply,

Thanos.

jb86

My Feedback: (8)

the 120 fs w/pump is about 35 oz. i have one, great running engine. lees' saito 125 is about 25 oz., you'll need some tail weight to balance against the engine. you might want to do some kin of a mock up. w/my gp extra 300 .60 w/120, i balanced it w/o covering to see where to put the servos, i ended up w/ 2 tower mini cs35 mg (1 ounce each) elev. and 1 hs5645 mg on the rudder all in the tail. mock it up w/engine cowl, ect. i tape the servos on to the sides of the fuse, just to hold things to see where it balances. know one thing about that pump, i burned up my 120, the pump was clogged. i sent it in for warranty service, they replaced the pump, ring and cylinder. run the engine atleast every 3 weeks or so, otherwise it will get clogged. i had it happen to my 91 fs two years ago also. run the engine, open the needle valve, if it don't richen, it's clogged.
jon b

R/C Lee

My Feedback: (3)

Thanos, Jon has an excellent point in that before you cover your Ultimate, rough install all of your equipment (engine, tank, battery, receiver, servos, pushrods, etc) and check the balance. That should tell you whether putting the elevator servos aft will result in a tail heavy airplane. You'll get a little tail weight with covering material and tail bracing, but that's easy to balance after covering. With my Saito, I had to mount my 6V 2200maH battery pack up against the firewall even though I had all of my servos in the fuselage near the cg. Your OS 120 will give you a little more nose weight which might be enough to balance the aft mounted el servos, but you'll have to check. By the way, since the airplane uses a lot of lite ply, be sure to use four pieces of triangle balsa to reinforce the fuselage along its length and use large triangle balsa to reinforce the firewall (with epoxy).
Got my new fg cowl from Fiberglass Specialties today and started cutting it out for the ST 3250. The cowl is very well made and is better than the first one I got from Stan's.
Keep in touch, Lee

baldrick

Hi all. I moved away from using triangular stock for fire walls and U/C mounts years ago. The problem with it is the direction of the grain in relation to the glue joint. Instead of this I now use west epoxy and fibre strands (either fibreglass or carbon tow strands cut to short lengths) Mix an approx amount to do the job so the strands are wet. Use your finger to force the mix into corners then wet your finger and run it over lightly till smooth. The strands all lock together and is relatively light, easily sanded if required.
I have heaps of building to do before I start my ulti but can't wait!!.
There is alot of great tips on here. Some of which I will try but I have a few ideas that I will impliment aswell. The cabanes will be replaces with stainless and the top wing will bolt on. Just don't personally like the idea of a pin holding the area with the most strain.
Happy building and flying guys.

R/C Lee

My Feedback: (3)

baldrick, good point about the tri stock and it sounds like the fibre strands and epoxy are a significant improvement. I'm glad you are going with stainless for the cabanes, as I was very disappointed at how easily the kit supplied cabanes twisted in my hard landing that did no damage to the wings or fuselage. Keep us updated on your build as well. Thanks, Lee

baldrick

I have an old ulti here at the moment. I bought it cheap to fix up but it's too far gone for that. I've had a good look at the construction and noted many area's that I personally am not happy with. The joy of stainless is you can go thinner but have more strength. I'm thinking of going stainless for the U/C as it can have lightening holes drilled in it.
What are other peoples opinion about the elevators and rudder construction? I'm a bit suspicious about them flexing during a snap roll or other more violent manouvers.
When I finally start it i'll let you know of the mods I do. I've got a back log of models as I do repair jobs for others so my table is pretty much always taken up. Plus 2 young ones and looking for a house... If there was 36 hours in a day I'd be building for 12. Dreams are free :-)

R/C Lee

My Feedback: (3)

baldrick, you might consider contacting Ken (see my 11/21 post) about a carbon fibre landing gear. I bought one from him to replace my Stan's "dural" gear, and I really like it. It's light, very strong, and it flexes nicely when I forget that the Ultimate likes to be flown down to a landing instead of stalling and falling that last 3 feet [&o]. As to the rudder and elevator construction, I haven't found it to be a problem, no matter how much stress I put on it. However, I used Sullivan carbon fibre tail bracing, tying the fin to the stab to the fuselage, so I haven't had a problem with flex during a snap or spin. There are a lot of good ideas throughout this thread that you might want to incorporate in your build. It's certainly an airplane worth building. Lee

baldrick

I'll check out the carbon u/c at some stage. The problem with NZ is you have to double the US dollar and add shipping which sometimes makes it very expensive. I'm going to go through all posts again and write bits down the look at the old ulti. I'm looking at putting in a 1.20 2stroke as I have one lying here and is quite light. I may get another engine for it but will see when building.

Keep up the good work guys

10-300

Hi guys,

On mind I also replaced the firewall with a 1/4 5 ply birch. I also replaced the 3 stringers from the firewall to the cockpit with hardwood, balsa doesn't cut it with that engine. also I left the 2 fuselage cutouts at the fuel tank compartment and glued them in. I'm using a YS 120 and figured that this engine is big on torque. So a little extra strenght at the front end wouldn't hurt. I also made extra mounting pads for the cabanes were they mount. The instruction have you bolting the cabanes too 1/8 light ply. I just added another 1/8 ply to the fuselage at that area where the cabanes bolt to the fuselage. I also used two servos mounted in the bottom wing. Just make hatches and hide the servos in the wing, one servo to drive 4 ailerons, I don't think so!! You can pick up the book by harry higley called "bipes" it will show you how to make the hatches for the ultimate. Just as a warning if there is a weak spot in this design its the landing gear!!!! whatever you can do to beef it up, do it you'll be glad you did. Also I replaced all the abs plastic with fiberglass. I am right know mounting the cowl then the wheel pants paint them and its off too the field. This plane goes together very nice. Its a great plane I have flown others and fell in love with it. The most important and the best advise is build it straight and align it straight. Don't forget the 3 degrees of right thrust. You'll need 3 degrees with the engine your going to use. And by-the-way your engine choice is nice very nice! That plane will probable be the best flying plane in your hanger. I have a feeling that after you fly your ultimate your going to be so happy that you'll want to build a bigger one. Also paint the canopy from the inside if your going to paint the frame thats molded into the canopy. The only thing I did that I'm probable sorry I did was I covered mine in 21st century fabric. I always have a love affair with bipes covered in fabric. My next project on deck is the balsa USA DVII. Good luck with the build.

WarbirdAirRacer

My Feedback: (16)

I just got done framing mine up about a 9 months ago and the kit is a awesome kit but if you cant speak and read German then it is not a good idea for you. I do have a build thread here in kit building forum...just do a search for my SN and you should find it.

WarbirdAirRacer

My Feedback: (16)

And now I am finishing up a CG Ultimate that I will be adding a gas engine too. I will post pics in a few days....guess its time for a bit of change from my old YS powered Ultimates.

FlyerBry

My Feedback: (8)

WarbirdAirRacer,

What gas engine have you chosen to go with on your Ultimate?

WarbirdAirRacer

My Feedback: (16)

I will be dropping a DA50 in it....it seems to be about the lightest with the power I am looking for....the ZDZ and others are close but I might aswel go for the bacon as they say. lol

WarbirdAirRacer

My Feedback: (16)

I also add alot of my own mods to the Ultimate even for YS and I will be doing the same other then sheeting the wings.....As I sheet the wings fully and make the top wing bolt on rather then that dumbass pin rod they have you do....if anyone has question on how to do it I will post the full steps in a day or 2.....please let me know.

RVM

You're going to put a DA50 on a 1.00-1.25 size CG Ultimate????

RVM

You may want to reconsider what you are doing. A DA50 (4.5lbs), fully sheeted wings etc. is going to make this bird super heavy and probably not a good flier. It's not the lightest to start with.

WarbirdAirRacer

My Feedback: (16)

no no I sheet the wings when I build from kit.....this one was already built when i got it so its not sheeted... and yes that is right on a CG ulitmate.

FlyerBry

My Feedback: (8)

Holy cow... Um... I'm going to refrain from making any further comment. However, I don't suppose you could post pictures of the final DA50 installation and also post a video of the maiden flight?

RVM

I will comment on this. Don't put a DA50 on this plane. It's too heavy, it is too powerful, it probably won't fit, the ignition will be too close to your RX unless you move your entire radio set up to the tail... that's just the beginning. You won't even be able to take off because the prop will be too big. Even a 4-blade would probably not clear the ground.

RVM

Oh, I want to see the video too. lol

baldrick

Hmmmm. I have suspicions about the DA in this aswell. But I like to be proved wrong My MA-5 Charger bipe with about 86" span has a ST3000 and it's not bad. Really needs a 50cc but it's a heck of alot bigger than the Ulti. Watch out for torque induced ground looping

thanosg2004

Hello again,
could someone give me the fuse width where the undercarriage is potitioned.
I found a gf undercarriage which seems to be 17 cm or 7" ( width at fuse ).

Best regards,

Thanos.

baldrick

The width of fuse at LG mount is 156mm or 6-1/8".

thanosg2004

Thanks Baldrick

WarbirdAirRacer

My Feedback: (16)

Okay, how about a ZDZ 40? or a brison 2.4 or 3.2 ? of does anyone have a aero works 27% or GP Ultimate they would be willing to trade for a fresh CG Ultimate in a ARF ?


I look at something like this as you never know till you try..but I know when to say when if it will cost more then just the plane....I was also planning on putting thr rx and battery in the tail anyway along with the elv. servos.