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-   -   Nitro models pusher Bobcat? (https://www.rcuniverse.com/forum/rc-jets-120/4588799-nitro-models-pusher-bobcat.html)

HeliTB 05-21-2008 09:32 PM

RE: Nitro models pusher Bobcat?
 
Okay...I've read some but not all of the thread. I'm thinking of getting a Bobcat 50, but curious about the retracts.

What kind?
Where to get them?
What does the complete set cost?

It would be nice to get the price and kind for both mechanical and air?

Thanks for any and all responses.

HobbyHut-RC 05-21-2008 09:49 PM

RE: Nitro models pusher Bobcat?
 
While we are on the subject of retracts - I guess to 302 from retracts.com is best suited for the Bobcat 50 - Does anyone know which set from robart would be surficiant?

HeliTB 05-22-2008 08:44 AM

RE: Nitro models pusher Bobcat?
 
Everyone,

I found the answer to my above posted questions in a post in page 125.

Stick Jammer...I do have a few questions for you/anyone for that matter that knows the answers.

1. Did the Robart 520w1 mount without issue?
2. What servo did you use?
3. Once I get the Robart 520w1, what else do I need?
4. Will I really need a thicker strut for the Bobcat 50? if so, what do you recommend?

I'm trying to determine my overall cost of ownership for the Bobcat 50 with all needed equipment (retracts, servos, receiver, batteries, etc) before I order one. As always any and all answers are greatly appreciated.

opjose 05-22-2008 10:31 AM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: Stick Jammer

Original: opjose


A harder ( non foam ) nose wheel will help keep the nose from being "pressed" down during takeoff.
With a slightly positive AOA the nose wheel should not be "pressed" at all unless the pilot is holding down elevator during the takeoff roll.




Even with one, the nose does get pressed "down" because of the leverage force of the engine.

We've seen it in several pictures taken of my Bobcat during takeoff. I changed the nose wheel out to something a bit harder to prevent this.


Stick Jammer 05-23-2008 10:40 AM

RE: Nitro models pusher Bobcat?
 

ORIGINAL: opjose



ORIGINAL: Stick Jammer

Original: opjose


A harder ( non foam ) nose wheel will help keep the nose from being "pressed" down during takeoff.
With a slightly positive AOA the nose wheel should not be "pressed" at all unless the pilot is holding down elevator during the takeoff roll.




Even with one, the nose does get pressed "down" because of the leverage force of the engine.

We've seen it in several pictures taken of my Bobcat during takeoff. I changed the nose wheel out to something a bit harder to prevent this.


I would tend to believe this is normal behavior for a foam wheel rolling at speed. If the nose was getting pushed down that hard the plane would likely never leave the ground. Either way, I can't see a foam wheel changing the AOA enough to matter.

Stick Jammer 05-23-2008 10:58 AM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: HeliTB

Everyone,

I found the answer to my above posted questions in a post in page 125.

Stick Jammer...I do have a few questions for you/anyone for that matter that knows the answers.

1. Did the Robart 520w1 mount without issue?
2. What servo did you use?
3. Once I get the Robart 520w1, what else do I need?
4. Will I really need a thicker strut for the Bobcat 50? if so, what do you recommend?

I'm trying to determine my overall cost of ownership for the Bobcat 50 with all needed equipment (retracts, servos, receiver, batteries, etc) before I order one. As always any and all answers are greatly appreciated.

My original Bobcat has fixed gear with an OS .55AX at a total cost of around $600. This is with a single HS-475HB for rudders and a single HS-475HB for elevator. Add about another $160 for retracts and mini servo for the control valve. I have another retract ready version still in the box but I don't see any issues with mounting the 520W1's. The 520W1's come with 3/16" wire for the mains and 5/32" wire for the nose gear. This is sufficient, struts are optional.

opjose 05-23-2008 11:02 AM

RE: Nitro models pusher Bobcat?
 
RE: Foam wheel

If the AOA is positive by say 2 degrees it doesn't seem to matter as you easily counteract this with a bit of up elevator.. as you would naturally.

If the AOA is negative or so, this just adds to the problem.

EINA 05-29-2008 11:27 AM

RE: Nitro models pusher Bobcat?
 
I am still deciding on my purchase of a bobcat, Ive got a 52 evolution and a fx61 os looking for planes. Whould any of these be a good engine for the bobcat or should I look for something else?

opjose 05-29-2008 12:06 PM

RE: Nitro models pusher Bobcat?
 
I would assume that it will do better with the .61 FX, though the FX does not produce the same power output ratios as say the AX.

However the .61FX may be closer to the performance of say a .55AX or so, which some people are flying here with great success.

Without a tuned pipe or other mechanism to boost output, the plane will not be a speed demon, buit it still should be a good flyer.

I fly mine with a GMS .76 engine and a Graupner 11x8 pusher prop...


Xairflyer 05-30-2008 05:29 AM

RE: Nitro models pusher Bobcat?
 
What way are you guys mounting your canopy's

moto-x 06-02-2008 06:09 PM

RE: Nitro models pusher Bobcat?
 
Finally got to maiden the Bobcat Sunday. Four clicks left, two up and she was trimmed great. When inverted I had to just think down on the stick and it was straight and true. Tweaked on the Supertiger 51 and gained some speed each time. Four flights for the day and was quite pleased. I will try and get some video next time out and post it on put-file.

HeliTB 06-02-2008 07:09 PM

RE: Nitro models pusher Bobcat?
 
What do you guys recommend? The Bobcat 50 or the Super Falcon 25?

opjose 06-03-2008 12:06 AM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: HeliTB

What do you guys recommend? The Bobcat 50 or the Super Falcon 25?
That's a bit of a strange question.

The 25 is a much smaller plane with no provisions or space for retracts... it is suited to electrification and I fly mine with two 3800mAh 11v batteries in parallel for 22v @ approximately 900 watts. It can also be flown with a glow engine and a fuel tank is provided.

The Bobcat 50 is almost twice as big, and can accept retracts. Some guys put Turbines on it too after modifying the fuse.

I also have a Falcon 1.20 which is again almost twice as big as the Bobcat .50. It features flaps as well.

All are different planes, so the question is sorta like asking "do you recommend oranges or grapes?".


HeliTB 06-03-2008 05:55 AM

RE: Nitro models pusher Bobcat?
 
opjose...I currently fly airplanes ranging from an Alpha 40 w/.46AX, Sig Kougar w/.46AX (I built), SuperSportster 40 w/.40FX, ModelAero AeroCat (small foam jet), and an Eflite Brio 10.

Thanks for clarifying my question being vague. My question is; what would be the logical one to purchase at this point (I'm ready to order today), keeping in mind I want to run either as nitro.

Thanks in advance for your advice.

HeiTB

opjose 06-03-2008 02:43 PM

RE: Nitro models pusher Bobcat?
 
I would classify all of these as being for an "advanced" flyer.

From the mix of your planes it sounds like you are advancing out of intermediate....

The Bobcats fly differently than any of the planes you are used to.

I'd suggest starting with the .25 to minimize complexity ( fixed gear only ) and get you used to flying these things.

Throw a glow engine on it and you'll have a blast with it, yet if you crash it the costs will not be seveare.

If you like the .25 you can always move to the .50 later with it's retracts, etc.


airborne14830 06-03-2008 03:01 PM

RE: Nitro models pusher Bobcat?
 
Can anyone tell me what size servo they are placing in the middle of the elevator when modifying to a single servo versus using two elevator servos? Also, I see some are using one to no servo for the rudder. How is this set-up working? I have a Bobcat 50, and I plan on using an evolution 61 fitted with 11X7 or a 12 X 4 pusher prop for power and install robart retacts.

Any thoughts on this would be great

opjose 06-03-2008 03:15 PM

RE: Nitro models pusher Bobcat?
 
You are NOT going to like it with a 12x4P prop.

Stick with the 11x7.

I didn't bother with the single elevator servo as I did not forsee a big advantage to all of the effort.

I use the rudder all the time on landings, so I'd say that you would be ill-advised to eliminate the rudders altogether.
I also prefer the dual rudder servo arrangement, as I had a problem one day with a servo that caused the surface to turn out on one side. I was able to turn the stick the other way to even things out while the plane was in flight, so I brought the plane in uneventfully.


littlepiston 06-03-2008 06:00 PM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: airborne14830

Can anyone tell me what size servo they are placing in the middle of the elevator when modifying to a single servo versus using two elevator servos? Also, I see some are using one to no servo for the rudder. How is this set-up working? I have a Bobcat 50, and I plan on using an evolution 61 fitted with 11X7 or a 12 X 4 pusher prop for power and install robart retacts.

Any thoughts on this would be great

this the servo im using:http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAYM2 you can also get it non digtal:http://www3.towerhobbies.com/cgi-bin...&I=LXCRS4&P=SM

the digital servo HS-5125 has plenty of power, i have a MW44 in my bob cat

Xairflyer 06-03-2008 08:14 PM

RE: Nitro models pusher Bobcat?
 
I have the single servo in the tailplane in my turbine conversion bobcat, and is a much better idea and not difficult to do, the two servo's with long linkages is not very good practice. The servo to use is a hitec HS5125 or just the HS125 non digital version, Go to page 82 post 2041 you can see pics of mine.

HeliTB 06-06-2008 09:49 PM

RE: Nitro models pusher Bobcat?
 
Well I made the plunge and ordered my Bobcat 50 today. I see the Tower .75 is the engine of choice because of price, but they are backordered until late June. I believe I will get the OS .75 AX for $194, since TH is offering $25 off purchases over $199, so I'll get it for $169. Yes I will purchase an extra glow plug to make it over $199.

Now for retracts. I see TH has some for $139, what do you guys recommend? and what servo for the retracts?

opjose 06-06-2008 10:37 PM

RE: Nitro models pusher Bobcat?
 

ORIGINAL: HeliTB

Now for retracts. I see TH has some for $139, what do you guys recommend? and what servo for the retracts?

Any standard servo, for the valve actuator, provided you are using pneumatic retracts.

Otherwise you'll have a bit of a time trying to get a servo into each wing for the retracts, and another for the nose, along with the stearing servo.


Boomerang1 06-07-2008 05:00 AM

RE: Nitro models pusher Bobcat?
 
Xairflyer, what turbine do you have in yours? I'm repairing a turbine conversion at present with a Wren 44.

My canopy has a fixed pin at the front & a sliding spring catch at the rear. It was not very secure due to the canopy flexing but I had to repair the canopy so I glued some 1.5 mm balsa from front to rear & it's now fine.

Mine has one, flat Hitec digital; servo in one of the booms with a very short linkage to the elevator. - John.

Xairflyer 06-07-2008 05:04 AM

RE: Nitro models pusher Bobcat?
 
MJ1400 same as the JetJoe 1400

Boomerang1 06-07-2008 05:11 AM

RE: Nitro models pusher Bobcat?
 
Hope you have success with your MJ1400, my friend had a jet joe & eventually gave up on it although it had a much bigger job to do pushing a Baby Boomerang. - John.

HeliTB 06-07-2008 05:58 PM

RE: Nitro models pusher Bobcat?
 
opjose...the reatracts will be pneumatic type.


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