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Nitro models pusher Bobcat?

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Old 08-31-2006, 06:36 PM
  #276
H.Dale
 
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Default RE: Nitro models pusher Bobcat?

Some pictures of a 44 installation.
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Old 08-31-2006, 07:07 PM
  #277
eaticus
 
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Default RE: Nitro models pusher Bobcat?

Mark,
Have you been able try other prop/motor setups? I am thinking to build it electric too!

I've been working on installing retracts. Will post pics later.

Thanks!

Dave

Quote:
ORIGINAL: MarkF

I flew mine this weekend . I converted it to electric and got one flight in. First off I used what I had laying around for power. Neu 1521 2y with 12s 1p 3700 evo batteries. This set up is a little to hot because I could only swing a 9 X 6 prop. It tacked out at 26000 on the ground and it felt and sounded really good but it just wouldn't get up and go once it was up in the air. I think you need at least a 10 inch prop at minimum but an 11 would be better. My cg was at 9 1/2 but I think 10 would be better. My batteries need to be all the way back as far as I could get them. I had to dremmel out all the bulkheads so they could slide all the way back to the wing spar rod. I got rid of the front wing rod and drilled it out to 1/4 20 to hold the wings on. I think this was the easiest way to secure the wings. She wieghed in at 9 lbs ready to fly and I felt she handled this weight with ease. Now I just need to get a different motor or less batteries before I can fly again.

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Old 08-31-2006, 07:46 PM
  #278
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Default RE: Nitro models pusher Bobcat?

umm.. correct me if I am wrong. When I used pusher props on my enforce the writing on the props face forward not backwards. I saw in the one post with pictures with the four stroke, the prop was on backwards.. the writing on the face of the prop should face the engine. Might be why some of you are having performace issues.
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Old 08-31-2006, 08:18 PM
  #279
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Default RE: Nitro models pusher Bobcat?

Hale that's looks good! The OS 91 fx should push like your M44 and the weight is about the same.
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Old 08-31-2006, 09:26 PM
  #280
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Default RE: Nitro models pusher Bobcat?

Finallly got a maiden flight. I was using a GMS .76 engine with an apc 10x8 pusher. Performance was actually pretty decent I estimate maybe 80+ mph looked slow, but then again its not a turbine, the engine tacked about 13,300 on the ground which is probally a little above what it was intended to run. I was also impressed that the plane can actually knife edge. Here's a link to the maiden flight, and following I show how short of a take off run it can do. My field is pretty rough grass as you can see. On the first landing the nose wheel turned in, thats why it came to a sudden stop after the first landing. Zagzoo my APC prop has the letters pointing backwards, so when you put the prop on the plane the letters are visible (just like a normal prop).

Here's a link to the maiden flight.

http://members.cox.net/adeloney/babybobcat.wmv
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Old 08-31-2006, 09:29 PM
  #281
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Default RE: Nitro models pusher Bobcat?

Well here's the video I promised. Acually, my daughters first try at videoing and creating a short clip. I think it's really cool even if she lost the landing part and the music is better than the the TopGun theme!!!LOL I can't wait for her next attempt. Enjoy[8D] Scott
http://smg.photobucket.com/albums/v3...nt=TakeOne.flv
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Old 08-31-2006, 09:59 PM
  #282
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Default RE: Nitro models pusher Bobcat?

Nice job on both the fight and the camera work. I have to go off on busness travel for a week so mine will be delayed until the middle of September.
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Old 08-31-2006, 10:11 PM
  #283
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Default RE: Nitro models pusher Bobcat?

mugenkidd, you have your prop on right. APC makes there pusher props diff. then others.

cool video.
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Old 09-01-2006, 12:33 AM
  #284
eaticus
 
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Default RE: Nitro models pusher Bobcat?

Awesome Video! Thank you for sharing

[img][/img]

Dave
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Old 09-01-2006, 12:43 AM
  #285
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Default RE: Nitro models pusher Bobcat?

SJN: if you throw a tuned pipe on that Magnum 65 i think you will be allot happier with your speed,
my ys-45 + tuned-pipe don't look so pretty on the ground, but in the air you don't even notice it,
I'M getting 90+ with my 45 so that Magnum 65 should rock with a tuned pipe.

don't get me wrong all the 61+ motors should do great, in fact i would like a bigger motor, but dew to my retract setup i lost 3/4 of a inch in clearance, so I'm pretty much stuck with the 10 in prop
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Old 09-01-2006, 12:52 AM
  #286
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Default RE: Nitro models pusher Bobcat?

eaticus: what retracts may i ask are you installing?
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Old 09-01-2006, 04:31 AM
  #287
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Default RE: Nitro models pusher Bobcat?

Zagoo, in my pics, its a normal prop on my 4 stroke, for breaking in the engine. I wanted the propairflow over it for better cooling.


Congrats on the maiden, and thanks for the video
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Old 09-01-2006, 05:46 AM
  #288
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Default RE: Nitro models pusher Bobcat?

Hey, if you want one bad enough you can get it here!!!!

[link=http://cgi.ebay.com/Bobcat-46-ARF-new-BVM-JET-OS-Saito-turbine_W0QQitemZ320023217971QQihZ011QQcategoryZ19 164QQrdZ1QQcmdZViewItem]Bobcat[/link]
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Old 09-01-2006, 09:44 AM
  #289
eaticus
 
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Default RE: Nitro models pusher Bobcat?

Topper,
I have a set of low height (1" height) Spring air that has been laying around the workshop for a little while. It fits pretty nice in the wings. My camara battery died last night and unable to post more pictures...

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Old 09-01-2006, 02:03 PM
  #290
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Default RE: Nitro models pusher Bobcat?

Quote:
Hale that's looks good! The OS 91 fx should push like your M44 and the weight is about the same
Please stop posting nonsense [:'(]. A turbine engine is irrelevant to a propeller based engine. Basic physisc will tell you why, most importantly, turbine efficiency does not decrease (with airspeed) as much as a propeller does ... Static thrust is one thing. You do not seem to know the other.
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Old 09-01-2006, 03:34 PM
  #291
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Default RE: Nitro models pusher Bobcat?

That was sort of uncalled for wasn't it? Bob
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Old 09-01-2006, 04:02 PM
  #292
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Default RE: Nitro models pusher Bobcat?


Quote:
ORIGINAL: B58

That was sort of uncalled for wasn't it? Bob
Or could have been a little better worded.
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Old 09-01-2006, 06:14 PM
  #293
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Default RE: Nitro models pusher Bobcat?

I am putting a Tower .75 on my Bobcat with a 11X8 pusher prop and installing Robart spring air retracts.
Matty
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Old 09-01-2006, 06:28 PM
  #294
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Default RE: Nitro models pusher Bobcat?

Matty, let us know how that turns out. I bet that is a decent combo.

I wish the propellor mfg. would make high pitched pusher props. I have sent an email to APC and never got a response.
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Old 09-01-2006, 08:10 PM
  #295
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n/a
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Old 09-01-2006, 08:16 PM
  #296
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n/a
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Old 09-01-2006, 08:24 PM
  #297
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Default RE: Nitro models pusher Bobcat?

Quote:
ORIGINAL: A10FLYR


Quote:
ORIGINAL: B58

That was sort of uncalled for wasn't it? Bob
Or could have been a little better worded.
French has always been the traditional language of diplomacy.[8D]
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Old 09-01-2006, 09:15 PM
  #298
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Default RE: Nitro models pusher Bobcat?

When you boys are finished can this thread please get back to information about the plane. It's amazing how it can all go down hill so quickly. I want to hear and see more information about the retract installations and motor and prop combinations.

Bassman
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Old 09-01-2006, 09:31 PM
  #299
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Default RE: Nitro models pusher Bobcat?

Tomorrow, I'll maiden mine with a Tower .75 and an APC 11x7 pusher prop. I have some other props as we to try. My buddy has a radar gun so I can get some flight speed data on the combo.
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Old 09-01-2006, 09:37 PM
  #300
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Default RE: Nitro models pusher Bobcat?

Some really strange engine choices by some.
I'd say the best thing is something like a YS45, again.
Some of the choices like B-58's are deliberately weighting down the plane to see how it will handle with a turbine. That makes sense.
But a four stroke does not seem appropriate at all.
Nor do some of the other two strokes seem like the right call. Just because something can haul a heavily loaded trainer straight up does not mean it will swing a small prop very fast for jet-like performance. A K&B 61 will probably get whupped by a YS45 in this plane.
Also...just putting a tuned pipe on any old two stroke will have a very limited performance gain, if any, if the engine is not timed and ported for a tuned pipe.
Surprised nobody has whipped out some older DF engines, like the old OS61 or 77, or a Rossi 61 or 81. Might be a good place to put one, and there are a lot of them gathering dust.
Just some stupid thoughts.
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