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CanoMod . Futaba-RC . A Main Hobbies

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Robbe Cuatro - Millennium - Nova - Dyna-X > anyone have a OS 91 in a Robbe
 
 
Rchover
Key Veteran
Location: Helping Customers!

Hi Folks,
I'm interested in hearing if any of you run a OS 91 in any of your Robbies?

I have a ys 80 in my futura SE and it is just Kick ass! and now that I'm spoiled with more power to spare, I'm toying with the idea if putting the os 91 in my nova.

could you tell me the pro's and con's of the 91, does it run as well as the ys80, I hear it has gobs more power than the 80 is this true?

Thanks in advance

McKoi"got to love the POWER"
03-05-2002 Over year old.
 
 
Christian Rose
Heliman
Location: Tengling, Germany

Hello McKoi

i am running OS SX-91 in my both Nova and my Futura SE. Fuel is Cool Power 12,5%. The Gear Ratio is 7,57:1-i bought the conversion kit at www.hobbycopter.de.
The Engine Mount unit of the Futura SE must be modified (you`ve to it cut 4mm) - but there are no additional problems.
I love the 15ccm Power and i will never use a 10ccm motor again. The 15ccm are very very silent (i use Zimmermann mufflers) and have much more power than a OS 61.

Best regards from Germany
Chris
03-05-2002 Over year old.
 
 
RCMarket
Key Veteran
Location: Belgium , Europe

Robbe

Hi

I can get you all Hobbycopter parts.
I accept paypal, also can supply Zimmermann mufflers, Blades, and Carbon upgrades

Let me know what you need
Alex
03-05-2002 Over year old.
 
 
Rchover
Key Veteran
Location: Helping Customers!

<>

a few questions?

1.do you need to modify the Nova engine mount?
2.or did you need to shim the nova mount?
3.what belt and what clutch are you using in the Nova w/ the 91?
(gear ratio)

3. blades size? 700,720's or bigger?
4. rotor speeds your 3d'in at?
5. which zimmerman Muffler are you using and nitro %?
6. anyone running a tuned pipe?

7. anyone in the USA running the 91?

thanks in advanced, sorry for all the questions.

McKoi
03-05-2002 Over year old.
 
 
RCMarket
Key Veteran
Location: Belgium , Europe

os91

Hi

i am running a special kit that desighn for Nova
The kit is:

Belt of 390mm
pinion 27t , rate of 1:7.57
special heavy duty clutch, bigger fan,(no need to cut the shroud)
shims.
Blades are 700-710

I use larger combustion muffler 1 piece for os91, possible to use header-pipe combination.
rotor speed 1700+tons of power, i use CP15,
EASY pitch of +-12
Hope it helps.
i can supply all those parts.
mail me
rcmkt@hotmail.com
03-05-2002 Over year old.
 
 
Rchover
Key Veteran
Location: Helping Customers!

Futurac,
I see, I hear you sell this stuff!!!

1:7.57 ? x 1700=12,869
1800=13,626

I thought the perfered gearing for this 91 should be more around 1:8.3or 1:8.6?

8.3x1700=14110


what is the peeK HP rpm rating on the os91?

McKoi
03-05-2002 Over year old.
 
 
Blair
Key Veteran
Location: Republic of Canuckistan

No Mckoi, the best gear ratio for the 91 is 8-1 or less.

The numbers you have are for the YS 80.

Blair
03-05-2002 Over year old.
 
 
RCMarket
Key Veteran
Location: Belgium , Europe

os91

Blair is right

Os91 use more tork,
Ys uses more rpm.

For futura se/nova its the optimal kit,
Its very expensive to produce different pinions, comparing to Millenium, with same conversion kit you have 3 different choices.
14t for ys
15t for os91
16t longer blades, less speed , high tork.
we reached with 16t CP15%, +-13 pitch. Great???
03-05-2002 Over year old.
 
 
Rchover
Key Veteran
Location: Helping Customers!

Blair,
are you running the 91???
If so what gearing and rpm's does it seem happy at????



McKoi
03-05-2002 Over year old.
 
 
heliraptor
Key Veteran
Location: Colchester, Essex, UK

OS 91 in an SE

Hi Guys

Not in a position to answer this one........................yet, however I have just got hold of a Futura SE, brand new and set up by Bob Johnston. It has had one or two setup flight's full stop and has every and I mean every Robbe metal upgrade including all the carbon stuff available.

Got it for a steal and the reason I'm posting......It is fitted with an OS91 and Hatori 650 tuned pipe.

I pick it up Thursday night so by Saturday evening I'll tell you all what its about.

Happy flying

Lee
03-05-2002 Over year old.
HOMEPAGE  
 
 
Rchover
Key Veteran
Location: Helping Customers!

proper os 91 gearing for 3d'in

ok
7.57 just seems really low,
Min air recommends 8.18 with the os 91
which seem to make more sence 8.18x1750=14,315prm

The Freya dudes are running 8.1-8.4 in the 91
8.4x1750=14700

robbe kit :
7.57x1750=13247
seems low to me


Bob J., Gary W., Mark K.??? any of you guys run the 91os yet?

McKoi
03-05-2002 Over year old.
 
 
RCMarket
Key Veteran
Location: Belgium , Europe

Os 91

Millenium conversions are running between 1:8-1:7.5

Futura conversion is 1:7.5
with use of 70-71cm blades, loaded engine you have the best power to
speed ratio, it was approved by Robbe, and some international pilots.
also if i am not wrong, the new Robbe quattro use the same gear.
I will be in Germany this week, i can bring final answer to all of you.
I am meeting the desigh people and team.
Hold tight, i will let you al know


Alex
03-05-2002 Over year old.
 
 
Blair
Key Veteran
Location: Republic of Canuckistan

I haven't got one yet (I'm waiting for the beta testing to stop ;-) But I have seen two at my field. One in an Xcell at around 8.2-1 and another in a JR Superio at around 7.6-1. Both were stump pullers. It seems the guys are still arguing over which is the best fuel to use. Sounds like 20% might be about right.

Blair
03-05-2002 Over year old.
 
 
Rchover
Key Veteran
Location: Helping Customers!

Blair:

what kind of issues does the os have, is it true some pilots are putting perry pumps on them?Do you know why they are doing this?

Mckoi
03-05-2002 Over year old.
 
 
Blair
Key Veteran
Location: Republic of Canuckistan

Issues

David Harkey would be the guy to ask. He fly's Xcells, but is quite up on the OS .91. Some of his FAI pilots were using the Perry (now Conelly) pump for better fuel flow. There were also some inital problems with overheating. I think both of those problems arose out of improper gear ratios as I haven't heard of any problems for awhile.

The benefits of the 91 that I see is that it's cheaper, easier to operate, and has less to go wrong than the YS 80.

I see some guys are starting to play with tuned exhaust sytems which I think defeats the whole purpose of this engine. That being crazy power
with little or no set up. Set it rich, then fly. Period!

It doesn't get any easier than that.

Blair
03-05-2002 Over year old.
 
 
Andy17
Senior Heliman
Location: Ellijay, GA

opps
03-06-2002 Over year old.
 
 
Andy17
Senior Heliman
Location: Ellijay, GA

I'm no expert but the 80 is great. I have one with 8.8 and it's got tons of power. I can do tic tocks and climb out of sight at the same time. Piro flips one right after the other with no sign of engine load. I'm sure someone can get one to bog down but not me. I'm running 700mm vblades and 105 tails, it's cool. I'm running 1750 on the head. I have seen the 91 it's just as impressive but has more vibration and the needles are very touchy. It was running 8,1.
03-06-2002 Over year old.
 
 
heliraptor
Key Veteran
Location: Colchester, Essex, UK

Flight times

Hi
On the stock Futura or Millenium tank what sort of flight times are you getting, say in comparison to a 61 engine.

Thanks

Lee
03-06-2002 Over year old.
HOMEPAGE  
 
 
johnw802
Heliman
Location: London. UK

Hi.
I have both a Millennium II & Futura SE both with OS91 in them, I use
cool power 15%, run Hatori 650 tuned pipes on both Helicopters.
The OS 91 works best at 15000 rpm, Millennium with the 13 tooth pinion gear will not work, over revs. need the 15 tooth pinion gear.
this will give a ratio of 8.00 with a head speed of 1750, a engine rpm of14000.
The Futura SE. three things I changed,the engine mount. the clutch and
the belt. The engine mount part No.S 4693. Futura Contest mount. this
will save you cutting the one you have. The belt changed to 390 mm Part No. S 4112. And the clutch this was changed for a 25 tooth this gives a ratio of 8.1 giving 1750 on the head and 14307 on the engine
does it go.This is with +10 -10.
Have orded the new head for the OS91 this should stop any overheating. Part No.T 72001000 if you get overheating trouble.
03-07-2002 Over year old.
 
 
Rchover
Key Veteran
Location: Helping Customers!

JohnW802,

thanks for that info , do you have over heating?

what's different about this new head that's going to keep it from over heating, lower compression?

this head is it from os and will it be avalible under warrentee?


thanks,
McKoi
03-07-2002 Over year old.
 
 
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Robbe Cuatro - Millennium - Nova - Dyna-X > anyone have a OS 91 in a Robbe
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