Navy_Flyer

It was not in a stall.

RoKit

Hi everyone .
As a new owner I finally found a relevant thread !! Have not read all the posts yet :-)
Recently I came across a Ultimate, at first I had no clue of the plane, but as I was offered it almost for free I gave it a new home.
The plane needs some care and I have started with test fitting a OS FS91iiP (pumped),, Looking at the cowl, It looks like this plane have had several different engines
in its past career.. Will a OS 91 be enough for reasonable performance ? I have an old refurbished Webra 1.20 (two stroke) but not sure I like the sound and weight of it.

Borseth

Hi, and congrats on a bargain!

I had an OS FS-91 in my first Ultimate.
It was a lightweight combo that flew great. Big loops and beautiful hammerheads. NOT unlimited verticals. Just enough power for IMAC Sportsmann in low winds I think. Basic is no problem.
If you want unlimited verticals you need the 1.20.

Here is a pic of mine.

RoKit

NICE !!! My cowling need some resin work and paint to even come close in finish..
I will go with the OS91 to begin with and go from there.. What prop size did you use on yours ?

Borseth

Master Airscrew Schimitar 14x8 IIRC.

RoKit

Thank you for the info.
I have APC14x6 and a MAS Scimitar 15x6, will try both and check where it takes me.

RoKit

Starting to suspect that the OS FS91 will give me CG problems,, unless I want to mount a lot of led up front (I dont like ballast)
Briefly checking the CG I will need 150-200 gram up front, (7-8 ounces)
What I understand the CG range is 25mm and I would like to start with forward point.
How and what is the best procedure checking the CG on this model ?

Borseth

I just put a piece of masking tape around the horizontal bar between the cabane struts after I transfered the CG up from the lower wing.
If you measure from the front edge of the front cabane the CG range is 70-95mm. Then you can just feel for the tape and lift the plane with your finger. This plane quite CG tolerant so if you start at the foremost point you should be safe. Since english is not my first language I have attached a picture to clear things up.

RoKit

Your English is perfectly understandable...
I use Swenglish... the Swedish version of English :-)

Yes I did the same,, transferring the CG from the drawing, I was considering if there is any other and more precise way.?
I will probably try to confirm the CG with a Vanessa method and try to minimize the need of ballast in the front.
At this point the weight is 3.9kg and I am not sure if I can go higher considering my "small" engine.

Borseth

Jeg forstĺr swenglish bra. Jeg er norsk

RoKit

Jamen det är ju grejt !!!

jescardin

My Feedback: (1)

In my ARF version I have the central C.G. position marked with an adhesive dot on the fuselage sides, just above low wing seat. For checking the CG. I just turn downside the model and put my fingers on the low wing at the marks positions.
Easy as this model still is quite handly size!

RoKit

Thanks.. That is of course an easy way.
I am always over cautious when I have a new model in my hands.
My increasingly bigger worries is about weight, according to my calculations I will need a lot of weight in the nose.

thnilsen

Have you checked the CG on it yet? Mine is nose heavy (kit built) when using a Saito 125 fitted with a slimline pitts style muffler with a weight very similar to the OS FS90ii. The saito is 618g on its own. The RX pack (4 cell 2400mha) is mounted against the inside of the firewall and I've got two 25g servos in the tail for each elevator. Fuel tank is mounted on CG.

- Thomas

RoKit

Yes the CG is at center of the CG-range meaning at 8.5 cm behind center of the main gear wheel,, with 200 gram ballast in the nose..
Note that my model is old, probably one from the first batch 30 years ago. I got it almost for free
My full size servos are slightly behind CG (2 for elevator, 1 for rudder and wing servos in lower wing for aileron, finally one for throttle)
The cowl is a heavy glasfibre with several "patches" however the model have never been repaired from what I can se,, I suspect that the model have had several different engines in the past.
I am not sure but the wood might be different or maybe the covering is heavy. I was just coming from my garage picking up my refurbished Webra 1.20 speed.
Will test mount the Webra and compare cause I dont have any bigger 4 stroke than the OS91. (well I have a Saito FA170 R3 but that´s another story)

Outrider6

My Feedback: (2)

I built a CG Ultimate back when they first came out, somewhere around 32-33 years ago (if my math is correct). I am about to start scratch-building one from downloaded Goldberg plans, and have already ordered some hardware, plus the cowl, wheelpants and canopy from Fiberglass Specialties. Also, I ordered the engine for it today. I will probably start a separate build thread on it, once I start cutting wood.

With all that being said, can I join the brotherhood?

RoKit

Wow.. That is interesting. !
I am sure the moderator will assign a member # for you.
I am looking forward to your build thread, What engine did you order ?

Some months ago I found one in a barn where it has been sitting for the last 20-30 years,
it was in rough condition and without engine. My plan is to use an old Webra speed 1.20.
(even if I dont like the sound of a two stroke in this type of model)
//

Outrider6

My Feedback: (2)

I found a killer deal on a new Saito 100 on ebay yesterday. I had one of those years ago on a Kyosho Giles, and loved it. I got curious, did a web search for that engine in this plane, and came across a few threads and 2 videos that showed the engine flying the Ultimate just fine, even on uplines. Since I am scratch-building this one, I plan to substitute balsa for most of the lite ply, so mine will be noticeably lighter than one from a kit, making the Saito 100 be even more effective on it. I turned around and ordered that engine, which is already on its way to me. I am saving significant money (way over $100) over the cost of any new 1.20-1.25 4-stroke (I really dislike any 2-stroke engines - mainly because of the sound), so it is a win/win for me.

I will be making other design changes on it as I build it, based on what I have read, plus ideas coming to me as I figure out which wood to order. I was a mechanical engineer, so I can't leave many things alone - I always feel the need to improve or fix things, which is fun to me (even when learning lessons from screwing up - lol).

Out of the 50+ kits I have built or assembled, my previous Ultimate was my favorite out of all of them (2nd only to my 1/3 H9 Cap 232). I loved the way that Ultimate flew - insanely aerobatic, yet it landed like a trainer.

RoKit

I agree,, 2 stroke have a hysterical sound..
But I had no other option and did not want to spend money on one more engine
(have many already).
So I actually planned to use my OS FS91 IIP,, but in the end i mounted the Webra on it.
Actually I think it would fly just fine with the OS91 but my club field is short and have obstacles on 2 sides,,
so I was thinking better "safe than sorry".. I was also reading some Ultimate reviews and most of them
seem to use 120 4stroke engines. I hope I will like the plane as much as you and others and then I might
go for a OS or Saito four stroke.,, Experimenting and "tinkering" is fun but my models tend to get heavy
Will post some pictures any day..

Outrider6

My Feedback: (2)

I now have on hand the plans, engine, cowl, canopy, wheelpants, wheels and some hardware, and the landing gear on order. It won't be long until I order some wood and start building this thing (gotta get that on the next credit card billing cycle).

Plus, I built one of these from a kit, not long after they first came out in the 80s.

Could someone ad me to the brotherhood list?

RoKit

I am not on the "list" either.. :-)
I suppose the thread is not so active anymore.

Here is some pictures of my Ultimate for your consideration.
When I have confirmed the flying characteristics and are happy with it, my plan is to refurbish/ re-cover it
in to another colour, cause the present old covering is not sticking and wrinkles no matter what I do.
The fiberglass cowl is patched several times in the past and is rather heavy. Looks like there have been several different
engines mounted in the past.

Initially I was aiming for my OS91iiP but it turned out heavy as I had to add weight for CG, but with the Webra 120
the CG turned out in the mid-range of the CG span. (I am not sure why its so tail heavy)

I will be happy to receive whatever comments & suggestions you might have. :-)

jescardin

My Feedback: (1)

Sorry for having left the thread aside a bit, but some personal and familiar issues has kept me out during this time.

As always, it is a pleasure to add you two, "RoKit" and "Outrider6", to the Brotherhood with the numbers #140 and #141 as shown on the list.

Wellcome to the Carl Golberd Ultimate 10-300 Brotherhood family!

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RoKit #140
Outrider6 #141

RoKit

Thank´s !!

Outrider6

My Feedback: (2)

Question for those who have actually scratch-built this plane.

When building the fuselage, how did you frame it:

1) Cut fuselage parts from lite-ply, to mimic the kit? As in tracing the patterns onto sheets of lite-ply, then cutting them to shape.

2) Cut the fuselage parts from balsa sheet, instead of lite-ply, to mimic the kit? As in gluing 3" or 4" balsa sheets together, then tracing the patterns onto the large sheets, then cutting them to shape.

3) Stick-frame the fuselage out of balsa? As in maintaining the outer shape, but built from sticks and narrow strips (like a SIG cub fuselage is built), instead of wide sheets.

I hope my description of the 3 different methods makes sense, or maybe someone did it yet another way.

I am trying to figure the best and most economical way to scratch build mine. Hopefully, a few have done this already, learned from the experience, and recall what they did. I can save significant weight by building it from balsa, instead of lite-ply. Plus, if done correctly, balsa would be even stronger than lite-ply, as well. As in bending strength; not impact strength.

acdii

At some point I plan to put this into my laser program to cut. I have been toying with using laminated balsa instead of LP for the fuse to save on length of stock. If I can knock out parts from 24" stock instead of 36-48" stock, it can save on shipping costs for short kits. Take the long sections, then puzzle fit them. On the lightening holes, create one full hole, and a puzzle fit hole then laminate the pieces together. This is something I plan to do when I get time to get back into the hobby. Right now I am busy with work and getting my property back into farm land for pasture land.