RE: Nitro models pusher Bobcat?
 

Help needed.
I order another bobcat that is retract ready. I have been waiting for the Robart 520's for the last 2 month from Tower. It was backorder until last Jan. Than nothing, Again backorder for Feb and again nothing. Now it backorder until late March.

Do anybody know where I can get retracts for the bobcat at a good price. I have finish building it, just wating for the retracts.

Thanks for the help

RE: Nitro models pusher Bobcat?
 

I just received an e-mail notification of activity in this sub, but on inspection, the link pointed to a piece of exploit code on another website. Of course, there doesn't appear to be ANY way to report this to this website, or to ask how the scammer new to contact me. (Has RCUniverse been compromised?)

Any way, for what it's worth, I mention it here as a salutary warning to everyone who audits this sub.

RE: Nitro models pusher Bobcat?
 

I have already installed the gas tank on my bobcat 50 facing the rear - It is going to be a pita to get it out - What potential problems am I facing with this set up - I now relize that I cannot let it get to low on fuel before landing...Any other major concerns? TIA


BTW - Engine OS 55AX 11x7 APC Pusher

RE: Nitro models pusher Bobcat?
 

Matto,

What motor are you using?

Thanks!

Tumbler

RE: Nitro models pusher Bobcat?
 

Matto,

You really need to reverse the tank...when the fuel gets low and you go in a dive, the clunk with be sucking air...other than that,,,,no problem with the way you set it up.

RE: Nitro models pusher Bobcat?
 

Well, it will be more of a PITA to gather all the pieces and throw them in a trash bag cause it's gonna flame out for sure. It will not work with the clunk forward in the tank. The second you go vertical the clunk is high and dry. Even level flight won't take long for it to suck air. Are your wings glued on? If not, it isn't that big of a deal. If they are glued, the anti-rotation rod is probably in the way to remove the tank. I would do whatever it takes to turn that tank around. ;)

RE: Nitro models pusher Bobcat?
 

I posted a reply to this question yesterday and for some reason it disappeared so I'll try again. I am assuming you're flying off grass because you mentioned "field". A bumpy field can definitely contribute to your problem. I'm not quite sure why you would be at half throttle when it leaps, maybe you meant half way down the field? Are you applying any elevator when it jumps? I'm also not sure what you meant by "almost hands off". Check your angle of attack as mentioned by opjose, the plane should have a slightly positive AOA when sitting on the gear. Also a good idea to re-check the CG, should be around 10.3" back from the wing leading edge at the fuse. Make sure the neutral elevator setting is correct, the trailing edge should be about 5mm up from a straight edge held against the bottom of the stab.

RE: Nitro models pusher Bobcat?
 

Tumbler,
I buy almost all my electric stuff from Hobbycity (Chinese need to eat also) anyway I am pushing this motor to the limit 6s @ 60amps as you can see the specs below. I have not flown this cat as of yet, but I did fly my Falcon25 (same thing as the Bobcat but smaller) for the first time last Sunday. The conditions were very windy... What a rush...[>:] This falcon25 has 4s @ 38a with about 3lbs 6oz thrust and flew with authority, not vertical but almost... Had a rough landing and had to repair the landing gear on the right rear all else was ok. Matto...

MT Dragon W50F1 610Kv

Dimensions: 50x55.5mm
Lipo Cell Range: 4-5
I/O (A) : 2A
Kv: 610RPM/V
Max Load: 55A
Max Efficiency: >86%
Resistance: 43mohm
Shaft Diameter: 6mm
Weight: 307g
Recomended Propellers;
5 Cell Lipo: 12x8

Recomended Model Weight: 2000-3600g

RE: Nitro models pusher Bobcat?
 

Matto,

I am curious to see how your .50 size flys as electric. My Falcon .25 does 140(139mph actual haha) out of a dive and 122 level. I am running 6s and added retracts. I ordered another one and will be adding flaps to slow down the landing speed.

Here is a vid of it.

http://www.rcgroups.com/forums/showt...ight=falcon+25



Tumbler

RE: Nitro models pusher Bobcat?
 

Tumbler, Wow your Falcon25 looks very fast and I must say good pilot work!!!

I am sure the setup for my Bobcat will fly great (9lbs thrust vs 8lbs 2oz RTF) but this motor is 610kv @ 6s will only yield 13,500 rpm max so it may not be as fast as you seem like you want to go... If you want huge speed you may have to go EDF setup (high amperage = high cost = high speed). Matto...

RE: Nitro models pusher Bobcat?
 

Unfortunatly the wings are glued - I also put velcro on the bottom of the tank to hold in place a little better...bad Idea - This is not going to be easy. Thanks for the replies.

RE: Nitro models pusher Bobcat?
 

You can cut the wood off the former at the front of the fuel tank w/o problems.

Cut it on either side of the tank so that you can later replace it with wood stock accross the cut area, which you can in turn screw in place.

I did this to make my tank easier to replace and remove, since I typically pull each plane's tank once each season to check everything.

This will permit you to push the tank "up" then forward and out with enough clearance.

RE: Nitro models pusher Bobcat?
 

I've got a GMS .25 engine here, looking for an airframe. Would one of the BobCat 25s fly OK with that engine? All the BobCat 25s I've read about in here seem to be electric powered or have .32s in them.

I don't require the model to be a brain-blistering speed-daemon, but I don't want it to be a complete, unflyable slug, either.

RE: Nitro models pusher Bobcat?
 

Original: reb92


If your wings are glued securely, you should be able to cut the anti-rotation rod with a hacksaw blade. This will take a little effort but at least you can get the tank out. I'm sure you gained a valuable lesson and it probably goes without saying, but never install a fuel tank that can't be removed. Good luck on the surgery. ;)

RE: Nitro models pusher Bobcat?
 

amcleod,,,,use the os 32 and you will be very happy. Use the os 25 and it barely flies. The 25 is not close to being enough engine.

RE: Nitro models pusher Bobcat?
 

I don't have a 32. I'm looking for an aeroplane that I can use my existing 25 on. If the BobCat 25 won't work, then too bad! I will have to find something else for that engine. Still planning to buy one of the bigger BobCats, and equip it with retracts and a 75, but I'm not going out and buy a 25-sized BobCat and 32 motor as well.

I was just hoping the 25 would fly the, uh 25-sized BobCat.

RE: Nitro models pusher Bobcat?
 

Great Planes has a spitfire .25 size that is real fun to fly - You might want to try one of those.

RE: Nitro models pusher Bobcat?
 

Do you have to do anything special with your engine to turn a pusher prop in the right direction? I have a evolution .61 that I would like to install in my Nitro Bobcat 50. Also, will the motor mounts be strong enough for this type of engine as well?

Also, can anyone point to the right thread that outlines how to mount your wings using bolt versus gluing? I am just trying to figure out which method is better.

Thanks

RE: Nitro models pusher Bobcat?
 

Heh...

I am awaiting a GMS .32 to put in my Bobcat 25, which is currently electrically powered.

I finally got the speed I wanted out of it by putting in TWO 4800mAh 11V packs in a 6S1P configuration to produce 22v @ 600 watts or so.

I realized that this was about the equivalent of a .25 engine, and that the .25 engine with 4oz of fuel would weight a heck of a lot less than my two big packs, so I decided to convert it back to glow.

The .25 should do fine with the right prop. I want to push it as fast as possible to I'm going with the .32.

RE: Nitro models pusher Bobcat?
 

Except for a very few engines, most glow engines cannot have their rotation directions reversed.

That means that you MUST use a pusher prop.

RE: Nitro models pusher Bobcat?
 

When using a pusher prop, the engine turns in the same direction as it would with a standard prop. This would be counter-clockwise when looking at the front of the engine. Just make sure you have the pusher prop orientation correct, the trailing edge is much thinner than the leading edge. The engine blocks that come with the plane are usable but fairly soft, I chose to make new ones from hardwood. I'm not a fan of gluing the wings on for the simple reason of maintenance and/or repairs. You're in the right thread, you just need to go back and do some reading. Trust me, its well worth your time. ;)

RE: Nitro models pusher Bobcat?
 

Stick jammer, I did buy the 46la, the thrust on this motor is pretty wimpy, as you said, 3lbs 5oz with 11x6 prop[&o]. I will install this on a frame that is around 3lbs RTF still looking for this frame... What thrust can I hope to get on a 55ax or 61fx. Matto..

RE: Nitro models pusher Bobcat?
 

mattosan1,
I haven't checked the static thrust on my 55AX but trust me with an APC 11x7p on 15% it flies this plane VERY well. The OS .55AX has been the engine of choice for a lot of people on this thread and everyone is quite happy with the performance. At 5 ounces lighter, I personally think its a much better choice than the .61FX.

The .46LA is a good engine but unfortunately its best suited for a trainer type plane. Its a bushed engine so the power to weight ratio is rather low. If you're looking for a jet type frame for the LA check out the Lanier Shrike 40. Not bad for 50 bucks and the .46LA should fly it nicely. These planes build very easy and fly very well.

http://www3.towerhobbies.com/cgi-bin...?&I=LXX403&P=7

RE: Nitro models pusher Bobcat?
 

did anybody tried os50 heli engine full throtle rpm is 22000

RE: Nitro models pusher Bobcat?
 

Finally read all 121 pages. Great info and reviews. Nice to see the manufacturer change the plane as time goes. For $99 its a great value, but plan on upgrading some hardware. Here are some of the changes I saw in my retract ready Bobcat-52...

CG corrected 10.3, had metal screws for boom/stab/wing, the wing actually had a small metric screw/blind nut to hold the wing in. Fuel tank facing forward. Landing gear in better position.

This thread revealed CRITICAL information that may save many maiden flights.
Elevator - neutral set 5mm higher than the flat bottom.
Positive AOA - to assist the take off (1-2 degrees...thats about 10-15mm higher at LE than wing root)
Spoilerons - start with 3mm (1/8in) at wing root and mix down elevator if needed
Frame - Epoxy boom supports and other areas for strength.

Debates between retract systems, engines, servos and props were very helpful.

I have 55AX and will try 11x7 and 10x8 later. Used single rudder/elevator servo (JR DS821 88oz/in) that came with the Spektrum. Tied the rudders using standard rod slid through a carbon-fiber tube for more stiffness. Glued weights in the nose and put battery in nose-gear compartment.
Thanks for all the advise and good reading...I will now get an experienced pilot to maiden the jet and teach me how to fly the Bobcat safely.
Richard