Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Its Bobcat nice

Reply
Old 08-07-2007, 12:54 PM
  #326
Carsten Groen
 
Carsten Groen's Avatar
 
Join Date: Nov 2004
Location: Denmark
Posts: 1,598
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Auch Terry,

it is a 11x8 I have

When I try to press on the end of the booms (just at the rudders) I need to apply much pressure to raise the front wheel, thats probably why it sticks to the ground. I also see the bumping when taking off, makes it a "bit" hairy....

I completely removed the stock (rear) gears, and put on a alu "bracket" type of gear, used the 4 bolt holes for the engine. I moved it to the front two holes then, this helped a little with the roll, but not near enough. I think I need to move the rear wheels 2" more forward. I'm just afraid that there is nothing in the fuse to put the bolts into at that point....

Regards,
Carsten
Carsten Groen is online now  
Reply With Quote
Old 08-07-2007, 12:58 PM
  #327
MMallory
 
Join Date: Dec 2001
Location: South Plainfield, NJ
Posts: 1,148
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Carsten,

It doesn't matter where your wheels are if the plane is set nose high on the gear. If your CG is set per the "revised" instructions, just make the nose a bit higher and the plane should rotate smoothly. The good news is since this is a pusher you can simply hold full up on the entire roll out as long as you remember to relax the elevator as soon as it breaks ground.
MMallory is offline  
Reply With Quote
Old 08-07-2007, 01:26 PM
  #328
Carsten Groen
 
Carsten Groen's Avatar
 
Join Date: Nov 2004
Location: Denmark
Posts: 1,598
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Mark,

I just moved the wheels 1" further forward, and changed the thrustline a little (moved 4 mm spacer to the "rear" screws on the engine (rear as seen on the plane, that would make them sit near the prop)

My plane is just a little nose high, how much "is ok" ?

Carsten
Carsten Groen is online now  
Reply With Quote
Old 08-07-2007, 01:32 PM
  #329
MMallory
 
Join Date: Dec 2001
Location: South Plainfield, NJ
Posts: 1,148
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Mine is approx. 10 degrees. If you set it on a table and the nose is obviously high, it is good enough. Once again your large prop may wind up being the cause of the problems. I am using a 10" and I plan to drop down to a 9".

Mark
MMallory is offline  
Reply With Quote
Old 08-07-2007, 02:16 PM
  #330
still4given
 
still4given's Avatar
 
Join Date: Jan 2006
Location: Victorville, CA
Posts: 1,520
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

I'm using an APC 11x6 and I haven't noticed any pitching when I reduce throttle but I've only flown it three times and the second flight was full throttle from start to finish since my throttle barrel locked up at wide open and I had to fly until it ran out of fuel. [X(]

I'm running the Tower 75 and I made aluminum blocks for motor mounts and they are perfectly even so I have only the thrust that was built into the frame. I'm maybe 1/8" higher than stock. Well, Maybe 1/4" when you figure the engine is a bit larger diameter as well. I have to fix the landing gear before I can fly it again. I tore the blocks out on the last landing. It was 6" off the ground when it ran out of air speed while landing. If I can get it fixed before the weekend, I'll do some low passes and reduce throttle to see if I have that problem.

Blessings, Terry
still4given is offline  
Reply With Quote
Old 08-07-2007, 02:42 PM
  #331
Carsten Groen
 
Carsten Groen's Avatar
 
Join Date: Nov 2004
Location: Denmark
Posts: 1,598
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Great Terry !

I'll try my "new setup" tomorrow at the field (weather and work permitting ) and post the results
Do you use the 11x6 on an OS61 ? (seems like a small prop ?)

Carsten
Carsten Groen is online now  
Reply With Quote
Old 08-07-2007, 02:57 PM
  #332
still4given
 
still4given's Avatar
 
Join Date: Jan 2006
Location: Victorville, CA
Posts: 1,520
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Hi Carsten,

No, I am running the 11x6 on a Tower 75. Yes it is a bit small but we are so limited with pusher props. The engine is turning about 15,500 on the ground. That is OK with the this engine as it is an RPM engine. I think it is rated at 17,000 peak. I just received a couple Graupner 11x8 pushers so that is what I will be trying on the next flight.

I'm looking forward to your results.

Blessings, Terry
still4given is offline  
Reply With Quote
Old 08-08-2007, 04:01 PM
  #333
Carsten Groen
 
Carsten Groen's Avatar
 
Join Date: Nov 2004
Location: Denmark
Posts: 1,598
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Just came back from the flying field!
The "drop" of the nose when removing throttle did not change (maybe it did, but then it was so little I did not notice it !)
The change of the landing gear helped a little on rollout, but the biggest help is to keep a little down elevator while it builds up speed on the runway, and then lift it off. WIll try again tomorrow (I'm not _that_ shaky anymore when flying it )

Regards,
Carsten
Carsten Groen is online now  
Reply With Quote
Old 08-19-2007, 05:14 PM
  #334
Grumman
 
Join Date: Feb 2005
Location: Lauderhill, FL
Posts: 99
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

[8D] Hello Gents!!! Does anyone have any information on flying the Falcon 120 with a 1.30 Nitro Engine???
I would like to know what size prop to go with... Also 2 or 3 bladed???
Thank You,
Mojo
Grumman is offline  
Reply With Quote
Old 08-20-2007, 02:40 PM
  #335
gooseF22
 
gooseF22's Avatar
 
Join Date: Aug 2006
Location: Fort Wayne, IN
Posts: 2,325
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

thrustline offset above the fuselage can cause those problems for sure. recommend you bring er back down stock value, with about 8 degrees downthrust. most of the thrust is at the tips of the prop anyway. You are forcing downpressure on the nose during takeoff. and you are haveing hi velocity air over the tail. bad combo.
gooseF22 is offline  
Reply With Quote
Old 08-20-2007, 02:46 PM
  #336
gooseF22
 
gooseF22's Avatar
 
Join Date: Aug 2006
Location: Fort Wayne, IN
Posts: 2,325
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Nitro, I saw posts that the GMS 120 wouldn't push it. You may not be satisfied either with the 1.30, I think there areonly

There are not many to choose from . Im not sure, if it can handle the rpm maybe a 14x8 zinger, or 14x6 APC. the next one up is a 16x10 mairscrew 3 blade. Im seeing 1.60's on it.

good luck. do a google search on pusher props, there are not many to choose from.

g
gooseF22 is offline  
Reply With Quote
Old 08-20-2007, 11:42 PM
  #337
angelrcdesign
 
Join Date: Feb 2004
Location: Weehawken, NJ
Posts: 543
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

For the Falcon 120 ........... put a Byron fan on it with a OS .91 0r Rossi
with 4-1/4 talicone.It will do a loop from level flight and take off is under 100 feet. And the C/G is perfect where it is. I have 10 flights on it and its getting better each time.
angelrcdesign is offline  
Reply With Quote
Old 08-22-2007, 08:14 AM
  #338
Grumman
 
Join Date: Feb 2005
Location: Lauderhill, FL
Posts: 99
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Hello Gents!!! Can someone measure the width between the 2 Booms please and give the distance from the engine mount to the ground... I am still away from my plane and I would like to continue to round up all the parts necessary to complete it.... I have everything to turn it into a Wren-54 Turbine Machine but I want to fly it with the Nitro 1.30 first..... PROP SIZE??? is the only issue left...I think the 3 Bladed is the way to go.... 14x10 or 15x8 have been suggested.....
Thanks Mojo
Grumman is offline  
Reply With Quote
Old 08-22-2007, 02:19 PM
  #339
Flyboy Dave
Moderator
 
Join Date: Mar 2002
Location: Pinon Hills, CA
Posts: 13,773
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

....if you are talking about the original Nitroplanes Bob-Cat....a 12" prop is all you
can put on it because of the distance between the booms, and the ground clearance.

FBD.
Flyboy Dave is offline  
Reply With Quote
Old 08-22-2007, 04:09 PM
  #340
Grumman
 
Join Date: Feb 2005
Location: Lauderhill, FL
Posts: 99
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice


Quote:
ORIGINAL: Flyboy Dave

....if you are talking about the original Nitroplanes Bob-Cat....a 12" prop is all you
can put on it because of the distance between the booms, and the ground clearance.

FBD.
Hello Flyboy!!! The propeller is for the Falcon 120 or it's been called White Falcon as well... Just a bigger version...
Thanks for checking in...
Mojo
Attached Thumbnails
Click image for larger version

Name:	Sq46548.jpg
Views:	4
Size:	210.0 KB
ID:	747174  
Grumman is offline  
Reply With Quote
Old 08-25-2007, 08:17 PM
  #341
Nightpilot
 
Join Date: Apr 2004
Location: Louisville, KY,
Posts: 37
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Here is my Bobcat.
Jett .60LX Turning A 10-6,.......you can only imagine the RPM.
Spring air retracts 300
Removable wings
Very stable
Servo canoes
Crisp roll rate, however, it does require all up trim and still have to hold a touch of up elevator. Yea, its CG properly.
Even with the Jett its still not exactly a real speedster, just stable and does neat flybys.
Attached Thumbnails
Click image for larger version

Name:	Nl29718.jpg
Views:	5
Size:	39.0 KB
ID:	749609   Click image for larger version

Name:	Hc94296.jpg
Views:	5
Size:	40.4 KB
ID:	749610   Click image for larger version

Name:	Di10820.jpg
Views:	5
Size:	36.7 KB
ID:	749611   Click image for larger version

Name:	Rl26137.jpg
Views:	3
Size:	51.1 KB
ID:	749612  
Nightpilot is offline  
Reply With Quote
Old 08-25-2007, 08:20 PM
  #342
Nightpilot
 
Join Date: Apr 2004
Location: Louisville, KY,
Posts: 37
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Whoa! wasnt expecting that big of pics to come thru!!! Sorry guys!!!
Nightpilot is offline  
Reply With Quote
Old 08-25-2007, 08:38 PM
  #343
Flyboy Dave
Moderator
 
Join Date: Mar 2002
Location: Pinon Hills, CA
Posts: 13,773
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

....I fixed it.

....set your picture size at 640x480. [sm=thumbup.gif]

FBD.
Flyboy Dave is offline  
Reply With Quote
Old 08-28-2007, 04:06 PM
  #344
zenoah11
 
Join Date: Aug 2007
Location: the hague, NETHERLANDS
Posts: 1
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

hello my name is Jacar (spanish) brocker (dutch )
I wanna build a very small bobcat like plane for a cox golden bee (so I mean really small...)
could someone help me with plans (mainly for an offeral idea, dimensions and stuff)

thanks
zenoah11 is offline  
Reply With Quote
Old 08-29-2007, 07:16 AM
  #345
MMallory
 
Join Date: Dec 2001
Location: South Plainfield, NJ
Posts: 1,148
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Look in the electric forum. There are many Bobcat like planes made for electric which would work well with Cox Bee.
MMallory is offline  
Reply With Quote
Old 08-30-2007, 11:26 AM
  #346
opjose
 
opjose's Avatar
 
Join Date: Nov 2005
Location: Poolesville, MD
Posts: 12,588
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice


Quote:
ORIGINAL: Flyboy Dave

....if you are talking about the original Nitroplanes Bob-Cat....a 12" prop is all you
can put on it because of the distance between the booms, and the ground clearance.

FBD.
I cut a 14" 3 blade prop down to 13" and it fits with about 1/2" to 1/4" clearance.
opjose is offline  
Reply With Quote
Old 08-30-2007, 11:27 AM
  #347
opjose
 
opjose's Avatar
 
Join Date: Nov 2005
Location: Poolesville, MD
Posts: 12,588
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Out of curiosity...

Are you guys balancing the plane for C.G. using a FULL or empy tank?

opjose is offline  
Reply With Quote
Old 08-30-2007, 11:56 AM
  #348
Flyboy Dave
Moderator
 
Join Date: Mar 2002
Location: Pinon Hills, CA
Posts: 13,773
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

....empty....the tank sits almost on the C/G.

FBD.
Flyboy Dave is offline  
Reply With Quote
Old 08-30-2007, 01:29 PM
  #349
thebluemax
 
thebluemax's Avatar
 
Join Date: Jan 2002
Location: Mullica Hill, NJ
Posts: 724
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

Since it is a low wing I would assume it would be balanced upside down? Also, if it has retracts, the retracts are in the down (landing) position?
thanks...
thebluemax is online now  
Reply With Quote
Old 08-30-2007, 01:47 PM
  #350
Flyboy Dave
Moderator
 
Join Date: Mar 2002
Location: Pinon Hills, CA
Posts: 13,773
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Its Bobcat nice

....yes, you would balance it up-side-down....and no, it doesn't have retracts.

FBD.
Flyboy Dave is offline  
Reply With Quote
Reply


Thread Tools
Search this Thread
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 08:31 PM.