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Nitro models pusher Bobcat?

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Old 10-06-2006, 08:53 AM
  #376
Jgwright
 
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Default RE: Nitro models pusher Bobcat?

Galen

The C of G was 255mm or just over 10". It was a touch too far forward and we needed some up trim. We may move it back 3mm when we fly at the weekend, it was not far out though and we did not run out of up elevator. The current consensus of 260mm or 10.25" is probably right.

John
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Old 10-06-2006, 11:25 AM
  #377
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Default RE: Nitro models pusher Bobcat?

That is about where my CG is now and I still noticed that I needed uptrim. Maybe something with the design. I would not say that it is a totaly flat bottom. More a semi-sym. airfoil. I may be wrong... but that is the way it looks to me.

as for inverted flight. It does need a tad of "down" elevator... but not much. It is actually a pretty neutral flying airplane. I had flown it this past weekend with a Jett 90lx on mine. It got after it pretty good. I am running a 11X7P and I estimate the level flight speed to be around 110mph. That is just a guess. I toasted the piston in it, so I have another piston/liner on the way. I think something got in there as it tore the piston up.

This is a great airplane.

Just make sure to that the boom mounts are secure and that you reinforce them with something. The front one is in there, but not good.


I will get some radar data when I get the new sleeve and piston in. It should be about another week.

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Old 10-06-2006, 07:58 PM
  #378
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Default RE: Nitro models pusher Bobcat?

What about this for a kit bashed Pusher Bobcat? It's a Bobcat fuse with an SU27 rear end.

I ordered another NitroPlanes Bobcat and am going to put a MW44 on it with retracts.

Hal
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Old 10-06-2006, 08:36 PM
  #379
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Default RE: Nitro models pusher Bobcat?

Hi
On my OS 91 with the11X7P I also estimate the level flight speed to be around 110mph. with a lot of rpm!

Raising the gear cleared a trimmed Master Airscrew 14x7 3-Blade Pusher prop. (13.5x7)
This is when the performance went through the roof.
I would suggest this setup to anyone with the power to swing the prop.
Johnny
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Old 10-06-2006, 09:39 PM
  #380
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Default RE: Nitro models pusher Bobcat?

TOPPER

I JUST GOT ONE OF THESE BOBCATS AUS DOLLARS $195 (THATS ABOUT $150 YOUR MONEY) DELIVERED I HAVE A SET OF OLD MK MECHANICAL RETRACTS FROM AN OLD MATTLASS PATTERN PLANE, I WAS GOING TO FIT UP A SET OF CYLINDERS OUR FITTER TURNED UP AT WORK, THEY WORK REALLY WELL. FOR THE MAINS I WAS GOING TO MAKE A INTAKE SHAPED POD TO MOUNT UNDER THE BOTTOM OF THE WING TO AVOID SURGERY ON THE WING, I AM THINKING OF MOUNTIN THIS TO THE EXISTING LANDING BLOCKS, I WILL MAKE IT UP AND INSTALL ON A LOW WING SPORT FLYER. I HAD TO LAUGH AT THE MANUAL IT QUOTES FLYING WEIGHT OF 5.5 LBS I DRY ASSEMBLED THE MODEL AND PLACED RADIO GEAR ENGINE (THUDER TIGER PRO 46) ETC ON THE SCALES CAME OUT AT 7.0 LBS. I NOTE ON ANOTHER THREAD OF A DISTRIBUTOR BEING OFFERED A SHIPMENT OF THESE WITH FACTORY RETRACTS WEIGHT 6.5 LBS. THE CHINESE HAVE A HABIT OF LOSING DETAIL, WORKING FOR ONE OF THE ITW DIVISIONS AS THEIR PURCHASING MANAGER I HAVE BECOME USED TO ORDERING BLACK WIDGETS AND RECIEVING WHITE THINGYS. ON THE NOTE OF TAKEOFF ISSUES, ONE OF MY FREINDS MAKES A PUSHER ULTRALIGHT, NAD IT HAS THE SAME TAKEOFF CHARACTERISTICKS, SOME OFF THE OWNERS CHOP THE THROTLE AND PULL UPSTICK AND THEN HIT THE THROTLE AND THEY ROTATE STRAIGHT AWAY AT 45%, MY FRIEND TELLS ME ITS DUE TO THE PROP WASH FORCE ON THE STABILISER BEING GREATER ON THE UNDERSIDE, HE HAS SUGGESTED CHANGING TO A FULL FLYING STABILISER INSTEAD OF THE STAB/ELEVATOR CONFIGURATION, THIS WOULD LET THE LEADING EDGE PICKUP THE FORCE OF THE PROP THRUST AND PUSH DOWN THE TAIL, HOWEVER THE ELEVATOR SENSITIVITY COULD BECOME VERY VARIED UNDER DIFFERENT THROTLE CONDITIONS, HOWEVER DUAL RATES COULD SORT THIS OUT. I WILL POST SOME PHOTOS ON THE RETRACT POD WHEN FINISHED.
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Old 10-06-2006, 11:46 PM
  #381
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Default RE: Nitro models pusher Bobcat?

noddy181, Please release your CAPS LOCK key.. you got some good information there but your post is very difficult to read.
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Old 10-07-2006, 12:54 AM
  #382
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Default RE: Nitro models pusher Bobcat?

as for the difficultly in taking off... all one has to do is raise the front nose wheel up just enought to give the plane 1-2 maybe 3deg. at the most positive incidence and it will rotate just fine. If I remember, Yellow Aircraft F-16 with full flying stabs needed to be setup this way to help it rotate easier. My bobcat did the same thing. I put a few degrees in it and it lifts off just fine.

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Old 10-07-2006, 12:57 AM
  #383
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Default RE: Nitro models pusher Bobcat?

With the Jett 90lx, I am getting around 16,500 with the apc 11x7P prop. I am sure after I get it fined tuned some that it will be a tad over 17,000.


I wish they made more pusher props then they do. i would like to run a 10x10 or an 11x8.5P on this. It would haul butt.


Love my jett motor. I did toast the sleeve and piston, but have another piston/sleeve on the way. Stupid mistake on my part. Fuel was foaming....

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Old 10-07-2006, 09:18 AM
  #384
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Default RE: Nitro models pusher Bobcat?

Many apologies will leave the caps lock off in future
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Old 10-07-2006, 10:30 AM
  #385
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Default RE: Nitro models pusher Bobcat?

Thanks!...we all appreciate it....
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Old 10-07-2006, 05:59 PM
  #386
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Default RE: Nitro models pusher Bobcat?

I am just about ready to put the wings on the first one I am building, a prop version. How did you guys do it? I am thinking of silicone glue so I could cut it with a wire later if I needed to remove the wings. Any other ideas? Bob
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Old 10-07-2006, 07:26 PM
  #387
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Default RE: Nitro models pusher Bobcat?

What I did was drill one hole on each side just to the rear of the front small anti-rotaion rod. I then slid the wings on the wing tube and used a pencil and marked them on the inside of the wing. I installed some 8-32 blind nuts in the wing. This allows you to bolt the wing on and remove it.

However, I just used it to hold the wings on while I epoxied the wings to the fuse. However, it would have held just fine without glueing.

Hope that helps.

I would not use silicone unless you also bolt the wing on.

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Old 10-07-2006, 08:00 PM
  #388
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Default RE: Nitro models pusher Bobcat?

Mine is shipping Monday...WooooHooooooooo !!
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Old 10-08-2006, 06:52 PM
  #389
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Default RE: Nitro models pusher Bobcat?


Quote:
ORIGINAL: noahb

What I did was drill one hole on each side just to the rear of the front small anti-rotaion rod. I then slid the wings on the wing tube and used a pencil and marked them on the inside of the wing. I installed some 8-32 blind nuts in the wing. This allows you to bolt the wing on and remove it.

However, I just used it to hold the wings on while I epoxied the wings to the fuse. However, it would have held just fine without glueing.

Hope that helps.

I would not use silicone unless you also bolt the wing on.

Well said noahb

Also:
If the wings are to be removable an anti-rotation pin will be needed on the back of the wing.
This eliminates trim changes during power up’s and downs.
Johnny
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Old 10-08-2006, 11:30 PM
  #390
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Default RE: Nitro models pusher Bobcat?

That is pretty much what I did (one at LE and second one behind wind tube) and it worked great... Well... Pilot error ensure its demise on its maiden flight...

http://www.youtube.com/watch?v=3_FniaqmFtw

Dave

Quote:
ORIGINAL: noahb

What I did was drill one hole on each side just to the rear of the front small anti-rotaion rod. I then slid the wings on the wing tube and used a pencil and marked them on the inside of the wing. I installed some 8-32 blind nuts in the wing. This allows you to bolt the wing on and remove it.

However, I just used it to hold the wings on while I epoxied the wings to the fuse. However, it would have held just fine without glueing.

Hope that helps.

I would not use silicone unless you also bolt the wing on.

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Old 10-09-2006, 02:25 AM
  #391
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Default RE: Nitro models pusher Bobcat?

All I did to join the wings was install blocking in each wing near the wing tube and in the bottom of the fuse. Then a installed a 1/2 wide spare carbon fiber strip from about 1" in on one wing root across bottom of fuse to other wing. Used wood screws through holes into the carbon strip and into the blocking. This way I don't have to disturb anything inside the fuse to remove the wings. Maybe just a tad unsightly as you see the exposed strip on the bottom of the plane but was the quickest easiest method for me. I fly the snot out of mine including full throttle dives and hammer on the elevator and repeated snap rolls. I've pushed this model to its limits. The first flight I had my muffler flew off and I deadsticked out of sight into a shrub and the ground. Just had a small repair in the leading edge of the wing and a few dings. Wings held secure. Probably going on 30 flights now. The only thing that has broken loose are the landing gear blocks, they aren't glued in very well so be sure to fix those if you don't go retracts.
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Old 10-09-2006, 08:29 AM
  #392
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Default RE: Nitro models pusher Bobcat?

Is anyone, or everyone, using two elev. servos? Bob
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Old 10-09-2006, 08:36 AM
  #393
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Default RE: Nitro models pusher Bobcat?

2 servos.
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Old 10-09-2006, 12:07 PM
  #394
B58
 
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Default RE: Nitro models pusher Bobcat?

I watched the video, but couldn't figure out what happened. Looked very fast. What kind of power? Bob
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Old 10-09-2006, 01:25 PM
  #395
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Default RE: Nitro models pusher Bobcat?

It was EDF. It is a Byron Fan converted to EDF using a Neumotor 2215. Full throttle is about 5000 watts. The static thrust is around 16-17 pounds (calculated exit velocity is around 180mph). The take-off was fast and smooth. The video was taken with my digital camera (not a camcorder) therefore the quality is rather poor. If you turn up the sound, you can hear "Oh, oh..." just before "The End"... [:@]

The pilot Error: Too little speed while turning. The plane stalled with no room to recover. I throttled down to conserve energy and forgot theat the plane is 15 pounds heavy (I was just flying my Giles 202 prior to the Bobcat.) I had pattern plane on my mind... [sm=bananahead.gif]

http://www.rcgroups.com/forums/showthread.php?t=567642

Dave
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Old 10-09-2006, 06:01 PM
  #396
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Default RE: Nitro models pusher Bobcat?

I run only one servo in the stab itself. It's a little work getting it in there, but a much better setup then how they want you to do it. I don't trust the angle at which the push rods are connected to the elevator on the stock setup. This is just me. I have a $400 motor on mine, and just don't want to risk it anymore then I have to. Plus I plan on flying it at higher speeds and don't trust there setup.

My two cents worth. There are lots of people that run the stock setup without mishaps.

Sorry to hear about your carsh m2energysoultions. That thing was a rocket while it lasted.

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Old 10-11-2006, 02:24 PM
  #397
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Default RE: Nitro models pusher Bobcat?

Hi,
Anyone got a byron fan shroud that they want to get rid of cheap?

Thanks!

Dave
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Old 10-12-2006, 06:05 AM
  #398
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Default RE: Nitro models pusher Bobcat?

Is anyone else having a problem keeping mufflers on the engine on this plane. I use lock washers and even resotered to locktite and double nutted the center screw. I have lost the nozzle end of one muffler and now can't seem to keep the nozzle end form turning in flight. The prop is balanced and there is virtually no vibration at full throttle on the ground. I don't have this problem on my front engined planes.

Bassman
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Old 10-12-2006, 07:26 AM
  #399
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Default RE: Nitro models pusher Bobcat?

I'm not a good picture taker, but here's my Bobcat. I've been flying the crap out of this plane so much that the cheap blue plastic
film on the top wing has pealed off in little small sections. Great flying plane. Everyone comments at the field how well it flares and lands.
Out of a dive, its got to be doing at least 125 easy.

MY SETUP:
YS 61-AR engine w/10x8 APC Macs pipe.
4 -3421 JR in empenage, 2 - JR 4131 in wing, 2 Futaba thro/steering
PPG clear coated
two tanks, 16oz & 8 oz Hayes
Bolt on wings ( interior 8-32 / blind nut 2" from LE)
old P&E functional struts from 1989 sitting around wait for a home.
Tetra wheels
6V 2000 mah NiH
8.5 lbs

I cut open the main gear support structure and reinforced the gear block and capped the cutout area with 1/8 ply.
Stripped off that ugly green anti glare and repainted it black. Looks much better, at least to me!
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Old 10-12-2006, 12:26 PM
  #400
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Default RE: Nitro models pusher Bobcat?

Quote:
ORIGINAL: bassman

Is anyone else having a problem keeping mufflers on the engine on this plane. I use lock washers and even resotered to locktite and double nutted the center screw. I have lost the nozzle end of one muffler and now can't seem to keep the nozzle end form turning in flight. The prop is balanced and there is virtually no vibration at full throttle on the ground. I don't have this problem on my front engined planes.

Bassman

You may need to JB Weld both ends of the muffler, that way it will never move again. I now have my muffler safety wired to the engine so if it comes loose, I won't lose it. You can kind of see it in my picture.

Myersflyers: Nice job well done. did you custom make the header?
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