Nitro models pusher Bobcat?
01-05-2008, 11:11 PM
#2752
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RE: Nitro models pusher Bobcat?
ORIGINAL: Capgains
I'm looking for a plane to do my 50 required logged flights, as part of my turbine waiver. A guy in my club just put one of these together with retacts, and a OS 61 (I'm not sure which model) and has offered it for sale. Is this thing capable of 100mph?
I'm looking for a plane to do my 50 required logged flights, as part of my turbine waiver. A guy in my club just put one of these together with retacts, and a OS 61 (I'm not sure which model) and has offered it for sale. Is this thing capable of 100mph?
Several have posted awhile back of 100+MPH readings with a radar gun. I do believe this airframe is capable of that but probably not much more with a glow engine. The added weight with too large of an engine creates the need for lead in the nose. This along with the limited prop clearance (and selection for pushers) seem to be the main factors governing maximum MPH. The retract ready version also has a thicker wing than the non-retract flavor. The aerodynamic advantage of retracts is probably cancelled out by the thicker wing. I think the non-retract version that has been fitted with retracts along with the best engine/prop/low AUW combination probably has the greatest speed potential excluding turbine power of course.
01-05-2008, 11:39 PM
#2753
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RE: Nitro models pusher Bobcat?
Hi I got my bobcat complete a while back have a old supertigre 61 on it (Italian) turning a 11/7 apc pusher prop at 28000 rpm I havent clocked it yet but I would bet it is 120 mph or so I have another plane that was clocked at 120 and thisone seems faster cant wate to check it for sure
01-06-2008, 12:50 AM
#2755
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RE: Nitro models pusher Bobcat?
I would like to see a super tigre 61 with a 11/7 prop turn 28000.....those engines are rated at top end 16,000....no way it would turn 28,000....must be a typo.....
01-06-2008, 12:56 AM
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RE: Nitro models pusher Bobcat?
ORIGINAL: keveaux
Hi I got my bobcat complete a while back have a old supertigre 61 on it (Italian) turning a 11/7 apc pusher prop at 28000 rpm I havent clocked it yet but I would bet it is 120 mph or so I have another plane that was clocked at 120 and thisone seems faster cant wate to check it for sure
Hi I got my bobcat complete a while back have a old supertigre 61 on it (Italian) turning a 11/7 apc pusher prop at 28000 rpm I havent clocked it yet but I would bet it is 120 mph or so I have another plane that was clocked at 120 and thisone seems faster cant wate to check it for sure
28,000 rpm from a SuperTigre? Hmmmm.
01-06-2008, 12:58 AM
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RE: Nitro models pusher Bobcat?
I swear its true I used a tac on my 9z tx sounded like a rabid bee not sure of the model but it has a blow threw pipe and blue head prob a df engine
01-06-2008, 01:08 AM
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RE: Nitro models pusher Bobcat?
im sure thats what it said i will chek it again i might have had it set fot a three blade prop but i just looked at it on tx its set to two blade now
01-06-2008, 01:40 AM
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RE: Nitro models pusher Bobcat?
Not sure how you peeps are getting even close to 100 mph with this plane...I have one and so does another member of my club
On mine i have an Os 55ax 11x6 prop stock muffler a little over 11k rpm's, clocked at 54 mph
The other one has the same motor turning a 10x6 prop an ultra thrust muffler, rpm's 13.5k clocked at 65 mph
On mine i have an Os 55ax 11x6 prop stock muffler a little over 11k rpm's, clocked at 54 mph
The other one has the same motor turning a 10x6 prop an ultra thrust muffler, rpm's 13.5k clocked at 65 mph
01-06-2008, 01:50 AM
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RE: Nitro models pusher Bobcat?
mine is 8.2 lbs no retracts.
the other I think is at 7 lbs (he thinks he has an older model) there where several differences between the to planes, when we talked about the building phase.
corrected weight typo..
the other I think is at 7 lbs (he thinks he has an older model) there where several differences between the to planes, when we talked about the building phase.
corrected weight typo..
01-06-2008, 01:59 AM
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RE: Nitro models pusher Bobcat?
are you at a high elavation? thiner air or somthing im at sea level havent clocked mine yet but it seems to be doing 100 +I have another plane that has been clocked at 120 and it seems close if not faster im turning a 11/7 at 28000 rpm but im going to have to tac it again to be sure begining to think that isnt to acurate
01-06-2008, 02:15 AM
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RE: Nitro models pusher Bobcat?
you might try a hier pich prop there is a thrust calc caled thrusthp to help yo figure it go to bmaps.net to get a free download
01-06-2008, 02:35 AM
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RE: Nitro models pusher Bobcat?
http://www.hoppenbrouwer-home.nl/ika...rusthpv20d.htm is the website to get thrust hp
01-06-2008, 04:19 AM
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RE: Nitro models pusher Bobcat?
ORIGINAL: keveaux
are you at a high elavation? thiner air or somthing im at sea level havent clocked mine yet but it seems to be doing 100 +I have another plane that has been clocked at 120 and it seems close if not faster im turning a 11/7 at 28000 rpm but im going to have to tac it again to be sure begining to think that isnt to acurate
are you at a high elavation? thiner air or somthing im at sea level havent clocked mine yet but it seems to be doing 100 +I have another plane that has been clocked at 120 and it seems close if not faster im turning a 11/7 at 28000 rpm but im going to have to tac it again to be sure begining to think that isnt to acurate
01-06-2008, 04:40 AM
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RE: Nitro models pusher Bobcat?
ORIGINAL: BillS
Canard has many intriguing possibilities. Appears that it would be easy to experiment. Hope you get an opportunity to experiment with the Bob Cat as a canard.
The possibilities for exchanging weight at the rear for front mounted weight are excellent. Moving weight up front partially solves issues with larger heaver engines.
Initial experiments could be as simple as servo operated aileron stock mounted to the front and bottom of the fuselage with no other airframe changes. A few flights would determine the size of the front mounted elevator. I often use screws on one side of the hinge so the control surface can be easily changed. For safety the airplane could be initially flown with both elevators operational but switchable at the radio.
Bill
RandyM.
Canards may be next.
Canards may be next.
The possibilities for exchanging weight at the rear for front mounted weight are excellent. Moving weight up front partially solves issues with larger heaver engines.
Initial experiments could be as simple as servo operated aileron stock mounted to the front and bottom of the fuselage with no other airframe changes. A few flights would determine the size of the front mounted elevator. I often use screws on one side of the hinge so the control surface can be easily changed. For safety the airplane could be initially flown with both elevators operational but switchable at the radio.
Bill
01-06-2008, 08:02 AM
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RE: Nitro models pusher Bobcat?
ORIGINAL: Wingspam
Not sure how you peeps are getting even close to 100 mph with this plane...I have one and so does another member of my club
On mine i have an Os 55ax 11x6 prop stock muffler a little over 11k rpm's, clocked at 54 mph
The other one has the same motor turning a 10x6 prop an ultra thrust muffler, rpm's 13.5k clocked at 65 mph
Not sure how you peeps are getting even close to 100 mph with this plane...I have one and so does another member of my club
On mine i have an Os 55ax 11x6 prop stock muffler a little over 11k rpm's, clocked at 54 mph
The other one has the same motor turning a 10x6 prop an ultra thrust muffler, rpm's 13.5k clocked at 65 mph
You're way low on RPM's. I have the same engine, stock muffler with an APC 11x7p and I'm getting 14,000 on the ground with 15%. My engine is still breaking in so it's even a little on the rich side. By the way, how'd you manage to have an AUW of 6.2 lbs.? Thats about a full pound lighter than everyone else who's posted including my own.
01-06-2008, 08:12 AM
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RE: Nitro models pusher Bobcat?
keveaux,
How about a picture of your plane showing the engine. A DF engine would seem like a real PITA of an installation on this plane due to the rear exhaust and rear carb configuration. If it is indeed a DF engine I'm surprised it's not over heating as you wouldn't be getting nearly the airflow past the head that they're designed for.
How about a picture of your plane showing the engine. A DF engine would seem like a real PITA of an installation on this plane due to the rear exhaust and rear carb configuration. If it is indeed a DF engine I'm surprised it's not over heating as you wouldn't be getting nearly the airflow past the head that they're designed for.
01-06-2008, 11:56 AM
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RE: Nitro models pusher Bobcat?
ORIGINAL: Stick Jammer
You're way low on RPM's. I have the same engine, stock muffler with an APC 11x7p and I'm getting 14,000 on the ground with 15%. My engine is still breaking in so it's even a little on the rich side. By the way, how'd you manage to have an AUW of 6.2 lbs.? Thats about a full pound lighter than everyone else who's posted including my own.
You're way low on RPM's. I have the same engine, stock muffler with an APC 11x7p and I'm getting 14,000 on the ground with 15%. My engine is still breaking in so it's even a little on the rich side. By the way, how'd you manage to have an AUW of 6.2 lbs.? Thats about a full pound lighter than everyone else who's posted including my own.
01-06-2008, 02:37 PM
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RE: Nitro models pusher Bobcat?
Very nice. That doesn't look like a Supertigre crank case, head or muffler, but the carburetor is Supertigre.
http://www3.towerhobbies.com/cgi-bin...?&I=LXFV75&P=7
http://www3.towerhobbies.com/cgi-bin...?&I=LXFV75&P=7
01-06-2008, 02:42 PM
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RE: Nitro models pusher Bobcat?
ORIGINAL: keveaux
heree are a fiew pictures of my bobcat
heree are a fiew pictures of my bobcat
But with the gear that far back is it able to rotate for take off?
I can't see the height of the nose wheel so I can't tell what the incidence would be.