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

opjose 02-07-2008 04:31 PM

RE: Nitro models pusher Bobcat?
 
I do not own a radar gun, but with the Graupner prop, the consensus is that it is WELL over 108 MPH.

Remember I'm flying with a ( but no tuned pipe though ) GMS .76 engine.

It will accelerate nose straight up as if gravity didn't exist.


Meekskin 02-07-2008 04:37 PM

RE: Nitro models pusher Bobcat?
 
I know the feeling when the nose is pointed up......looks like a rocket.......and..........a high speed pass making a slight left turn is breathtaking. What a pretty sight as it screems past.............love this plane.........I'm using the 10X7 APC prop and its turning 15500 on the ground and when it unloads in the air its got to be 16 to 17 K..

Nitrodan73 02-09-2008 09:43 AM

RE: Nitro models pusher Bobcat?
 
I am Meekskins radar guy and I will back him up on that speed of 122 mph. The reading I got just before the 122 was 114 so I know he was mooovving!!! The other high speed from a .25 size bobcat was 104mph. I know. I was about 5 feet away as it passed! Crazy Old Man!

Does anyone have an EDF mounted on a 50 size Bobcat? If I get one, I would like to try an EDF. I'm sure it would beat 122! I know OPjose has one on his 25.

Opjose, do you have video of your 25 EDF Bobcat?

opjose 02-09-2008 05:15 PM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: Nitrodan73

Does anyone have an EDF mounted on a 50 size Bobcat? If I get one, I would like to try an EDF. I'm sure it would beat 122! I know OPjose has one on his 25.

Opjose, do you have video of your 25 EDF Bobcat?
No I do not have an EDF, though I've been looking for an alternative power source.

PhilLin 02-09-2008 06:46 PM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: Nitrodan73

....Does anyone have an EDF mounted on a 50 size Bobcat? If I get one, I would like to try an EDF. I'm sure it would beat 122! I know OPjose has one on his 25.

Opjose, do you have video of your 25 EDF Bobcat?
I posted some pixs of mine here earlier. Its had about 8 flights & been fully trimmed out before the weather went south around this parts. Its not conversion of a Nitro Bobcat but the slightly larger Keecat from A-K or Richmodel. Have not had a chance to doppler its speed, but easily faster than 100mph with a tame 8-lb static thrust. Will probably swap out motor for 11-lbs thrust soon as I get more familiar with its handling.

Phil

Boomerang1 02-10-2008 01:49 AM

RE: Nitro models pusher Bobcat?
 
Hi Guys, count me in on this thread. I bought one today from a friend but it's a bit sad.

The method he used for mounting the retracts has not worked so everything is loose, top sheeting is split, the tailplane has had the film burnt off it, the canopy is broken and the fuselage has cracks in it & the paint is scratched on the nose.

What the realestate guys would call a Fixer - upper I suppose!

115 pages, looks like I have a lot of reading to catch up on!

Are the instructions that came with the model available as a download? If not, clues for control throws & CG? - John.

Meekskin 02-10-2008 01:55 AM

RE: Nitro models pusher Bobcat?
 
Well another good speed run this morning for my bobcat 52..........124 mph.......fastest speed yet and that may be my top for a while. I don't think a EDF will beat my speeds but lets see what you can post. comments by nitrodan are true because he was there today and again was the Radar Man for my 124....next fasest jet today was 117 until a mishap caused by a stuck throttle.

sushimack 02-10-2008 02:34 AM

RE: Nitro models pusher Bobcat?
 
Hi guys,
I'm looking to buy an F-18 Hornet 90 size prop new or used ,anybody can help?
Thanks ,Isaac

Stick Jammer 02-10-2008 10:04 AM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: Boomerang1

Hi Guys, count me in on this thread. I bought one today from a friend but it's a bit sad.

The method he used for mounting the retracts has not worked so everything is loose, top sheeting is split, the tailplane has had the film burnt off it, the canopy is broken and the fuselage has cracks in it & the paint is scratched on the nose.

What the realestate guys would call a Fixer - upper I suppose!

115 pages, looks like I have a lot of reading to catch up on!

Are the instructions that came with the model available as a download? If not, clues for control throws & CG? - John.

CG should be around 10.3" behind the wing leading edge at the fuse.

Manual recommended control throws are:

Elevator - 15mm up and down
Ailerons - 25mm up and down
Rudders - 10mm left and right

My personal settings are:

Elevator - low rate 15mm, high rate 25mm (for landing)
Ailerons - 15mm (25mm is way too much)
Rudders - 15mm

Good luck on the rebuild. ;)

flt lt hurdy 02-10-2008 12:04 PM

RE: Nitro models pusher Bobcat?
 
11oz lead in the nose to balance her?? AUW 9.25 lbs EEK!!!!! (err..how much does everyone else's weigh?? )

Got an OS 61 fx in it and have a Carbon Copy carbon fibre u/c... gonna be flying Lurleen Lumpkin sooooon....

Anyone else got a heavyweight kitty??

Markcp 02-10-2008 12:26 PM

RE: Nitro models pusher Bobcat?
 
1 Attachment(s)
I have one these setup for EDF, I have not flown it yet. I modified the back of the fuse to improve airflow to the fan. It is a Hoaye 4" fan with a Hacker outrunner running on 10s. turns the fan at 26,000 at 2300 watts. No retracts and it weighs 7 lbs 10 oz. If it flys well I will consider retracts. I did change the gear, it is lighter and much less drag than stock.[image

Meekskin 02-10-2008 03:46 PM

RE: Nitro models pusher Bobcat?
 
My bobcat weight is 7 lbs. 12 oz. and it has retracts. I would suggest taking the 11 oz. of lead out and moving the battery up front. try to stay under 8 lbs and you will love how she flies.

flt lt hurdy 02-10-2008 03:53 PM

RE: Nitro models pusher Bobcat?
 
...errr thats including the battery up the nose! lol


... just as well I have heavy duty u/c on it for the landings..

Stick Jammer 02-10-2008 04:52 PM

RE: Nitro models pusher Bobcat?
 

ORIGINAL: flt lt hurdy

11oz lead in the nose to balance her?? AUW 9.25 lbs EEK!!!!! (err..how much does everyone else's weigh?? )

Got an OS 61 fx in it and have a Carbon Copy carbon fibre u/c... gonna be flying Lurleen Lumpkin sooooon....

Anyone else got a heavyweight kitty??

Sounds a little odd. Mine has 3/16 wire fixed gear, O.S. 55AX with stock muffler, 5-cell battery just behind the nose gear former. AUW is 7 lbs. 3 oz . Even with the 61FX you shouldn't be that heavy. The 61FX is about 5 oz. heavier than the 55AX which should translate to just a couple of ounces of lead all the way in the nose. Not sure why you're so out of balance to need that extra 11 oz.

flt lt hurdy 02-10-2008 05:48 PM

RE: Nitro models pusher Bobcat?
 
1 Attachment(s)
[img][/img][img][/img]



here's the u/c and engine is as far back as I thought possible...

.. the wheels are in the same position as the wire u/c... maybe I should move the u/c forward or just grit my teef and give it a go..

opjose 02-10-2008 06:32 PM

RE: Nitro models pusher Bobcat?
 
Eh, that engine looks to be as far FORWARD as possible.

Moving it further back should move the prop out behind the plane more.

Even my "stock" installation has it much further back than what you have.


opjose 02-10-2008 06:34 PM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: Markcp

I have one these setup for EDF, I have not flown it yet. I modified the back of the fuse to improve airflow to the fan. It is a Hoaye 4" fan with a Hacker outrunner running on 10s. turns the fan at 26,000 at 2300 watts. No retracts and it weighs 7 lbs 10 oz. If it flys well I will consider retracts. I did change the gear, it is lighter and much less drag than stock.[image
Beautiful work. I wouldn't have known that you reshaped the fuse manually.

Where did you purchase the FAN? Links?

Thanks!


Darklotus 02-10-2008 06:39 PM

RE: Nitro models pusher Bobcat?
 
Hi everyone,

I just spent about 4 hours going through this thread, and only made it about halfway lol. I just ordered mine today, and was wondering the best setup for this plane? I was hoping to take a little bit of a short cut, and just ask instead of reading for another 4 hours lol. I'm looking for the most speed possible without braking the bank.

Thanks,

James

BillS 02-10-2008 06:57 PM

RE: Nitro models pusher Bobcat?
 
I used a similar fixed gear and mounted the wheel CL 2" behind the CG because I was afraid it would not rotate on demand. With standard servos all around and Sub-C batteries up front the all up weight is 7 pounds 7oz.

Bill

opjose 02-10-2008 07:06 PM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: Darklotus

Hi everyone,

I just spent about 4 hours going through this thread, and only made it about halfway lol. I just ordered mine today, and was wondering the best setup for this plane? I was hoping to take a little bit of a short cut, and just ask instead of reading for another 4 hours lol. I'm looking for the most speed possible without braking the bank.

Thanks,

James
Spend the time to go through the thread.... it's worth the effort and will answer your questions, as there are many photos included in prior posts.


NM_Mark 02-10-2008 07:24 PM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: Markcp

I have one these setup for EDF, I have not flown it yet. I modified the back of the fuse to improve airflow to the fan. It is a Hoaye 4" fan with a Hacker outrunner running on 10s. turns the fan at 26,000 at 2300 watts. No retracts and it weighs 7 lbs 10 oz. If it flys well I will consider retracts. I did change the gear, it is lighter and much less drag than stock.[image

That setup looks INCREDIBLE - Nice Work!!

Mark

Markcp 02-10-2008 08:11 PM

RE: Nitro models pusher Bobcat?
 
here is a link to my build thread
[link]http://www.rcgroups.com/forums/showthread.php?t=669348&highlight=bobcat+50[/link]http://www.rcgroups.com/forums/showthread.php?t=669348&highlight=bobcat+50

all the info is here , you can se how much I removed from the rear section, even between the wings is 1/32 ply that is concave to match the fan. The goal was to get the fan lower with cleaner air. I have done a lot of scratch built EDF so I have some experience with this.

The plane is nice for the money but it could be so much better, the airfoil is way too thick for one and some of the parts are way too heavy (each boom weighs 10 oz) I sure I could replace them at 5 oz each saving 10 oz total

still it is a bargain at the price and we can all experiment with them
I will post a flight report and video soon

Boomerang1 02-11-2008 01:58 AM

RE: Nitro models pusher Bobcat?
 

Good luck on the rebuild.
Thanks Stick Jammer, info noted. It was offered to me with 2 turbines at
a price I could not refuse & had the retracts & quality servos included so I
snapped up the bargain!

I will have to repaint the fuse & recover most of it so I'll completely sheet
the tailplane, cover the wing in Sig Coverall & paint the lot.

Working on fitting the retracts (properly) first up. - John.

Stick Jammer 02-11-2008 08:17 AM

RE: Nitro models pusher Bobcat?
 
Original: Markcp


The plane is nice for the money but it could be so much better, the airfoil is way too thick for one and some of the parts are way too heavy (each boom weighs 10 oz) I sure I could replace them at 5 oz each saving 10 oz total
It seems that for the most part everyone expects this plane to go ballistic when in reality it's not designed to break any speed records or even come close. It's a glow powered sport jet. The booms are constructed with light ply in addition to balsa. To get them down to 5 oz. you would probably have to build them entirely from balsa which personally I would not trust to hold up the stab. IMO, an AUW of less than 8 lbs. for this size and type of plane is pretty good. I will agree, at $99 it does lend itself well to experimentation.


Stick Jammer 02-11-2008 08:23 AM

RE: Nitro models pusher Bobcat?
 


ORIGINAL: Darklotus

Hi everyone,

I just spent about 4 hours going through this thread, and only made it about halfway lol. I just ordered mine today, and was wondering the best setup for this plane? I was hoping to take a little bit of a short cut, and just ask instead of reading for another 4 hours lol. I'm looking for the most speed possible without braking the bank.

Thanks,

James
I second opjose's advice. There's a ton of useful information most of which is contained in the second half of this thread. ;)


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