RE: Nitro models pusher Bobcat?
 

I agree with opjose. there are only two props anygood on this setup. 11x7 apc and 11x8 graupner pushers. depending on your motor power and max rpm. I run the 8 because I have a .90, and it cannot rev like the .75.

It will develop more than adequate static thrust with an 11 inch prop.


different topic: ran the .25 cat with the 8SA123 and 1600 medusa today its a real screamer. guessing a little over 100 with the fixed gear. so much power! meter said 1200 watts. running Cam 7x6 prop now and 70 amps.

It would do the same with a 6S 4000 lipo in case anyone wanted to know.

g

RE: Nitro models pusher Bobcat?
 

We have 2 Cats here in our hangar... One has SpringAir 302's the other has Robart 520W1. We like the Robarts better. SpringAir $190.00. Robart $135.00. The Robarts are much slower and softer on retract than the SpringAir. Easier on the airframe and looks nicer too.

RE: Nitro models pusher Bobcat?
 

It goes great in the Bobcat bags of power, only get about 5mins though.

RE: Nitro models pusher Bobcat?
 

I hit a hole in the runway and broke the wire leg on the right hand side at the weekend, when I went to fit a new one I realised that the wooden block had came away inside the wing.

I still have the remains of my first bobcat, so I opened up the wing to investigate how it was done and where the formers were before I got at the good one with the knife!

It was plain to see there was not much holding the blocks in place, so I made some measurements on my Bobcat and cut the wing open at the top as the blocks are glued to the bottom surface.

I added in some extra 1/4" ply pieces and some hardwood cross pieces to spread the load to the other rib which is also ply, this way the undercarriage loads will be better distributed.
In it's present configuration you could easily pull the legs apart and snap them out.

I decided to open the other side and do the same, I now also intend to turn the gear around to get it closer to the CG for better ground rotation.

I have attached two photo's with some measurements that may be off use to others, you can see from the one of the old wing how things are laid out inside and from my existing Bobcat where I have added in new wood.

RE: Nitro models pusher Bobcat?
 

Hi guys,

I'm installing SpringAir 302 retracts, and need help with the nose gear pull pull system. Does anyone have pictures of their nose gear installation? It would help greatly, wanna maiden it this coming saturday as that's all there is left to do. Thanks!!!!!!!

RE: Nitro models pusher Bobcat?
 

Just set up a basic Pull-Pull using a 2-56 pull-pull set-up and just attatch the clevis's to the servo and the other to the steering arm on the nose gear!

RE: Nitro models pusher Bobcat?
 

Guess what arrived today? My BobCat, my retracts (Robart 520w1) and my motor (OS .55 AX). Wow and they told me Christmas was in December.

RE: Nitro models pusher Bobcat?
 

Does yours retract forwards?

I bought mine damaged & am repairing it but the previous owner attached a servo directly to the retract unit. - John.

RE: Nitro models pusher Bobcat?
 

Hi Boomerang1,

My retracts fold back towards the tail, they're 302 flat mounts. I got pix of the retract install from the other threads, and everything's all right at the moment. I was just wondering if anybody had the AUW of the bobcat with retracts? Mine seems to be a little on the heavy side. I also moved the servos to one side to get a central position for the steering servo. So far, so good. On the other hand, how many gear cycles can you get with 100 psi in the springairs? I am only able to get one clean cycle, and after that, the nose gear doesn't retract completely. Is this normal?

RE: Nitro models pusher Bobcat?
 

Well I guess I am an amateur. I got a Bobcat, stuck a Super Tiger 45 on it with an apc 10X7 pusher prop, took an OS muffler had my brother-in-law take it to the machine shop where he works, they made a brass (round) plate to fit the muffler, I reversed it blowing backwards to push the exhaust away from the plane.

Balanced it at 10.5 " from the L E ( as stated in the manual). Put solid landing gear on the wings and a locked down retract in the nose.

Fueled it up and flew it.

As the old saying goes KISS.

RE: Nitro models pusher Bobcat?
 

Oh yeah, did not even think of any servos other than standard Futaba and Hitech. put in a bunch of extensions, Y's , hooked them all together and bolted the wing on with a 4-40 plastic bolt and blind nut.

RE: Nitro models pusher Bobcat?
 

How's it fly that way?

RE: Nitro models pusher Bobcat?
 

It flew fine.

My second flight, got a little cocky, added more elevator, and more ailerons, got into a little trouble, brougt in, and luckily noticed I had lost a wheel so I bled out all the speed I could, and landed it.

Bent the wheeless landing gear, brought it home and strengthened that one, put a new wheel on it and will take it back up Friday, weather permitting.

RE: Nitro models pusher Bobcat?
 

How many and what length servo extensions will be needed for this? I am preparing to start mine now that the P-40 and Corsair are done.


Thanks Shane

RE: Nitro models pusher Bobcat?
 

Let me get back to you, I will have to go over ny notes, will let you know by tomorrow.


Hank

RE: Nitro models pusher Bobcat?
 

Thanks Hank, appreciate it..


Shane

RE: Nitro models pusher Bobcat?
 

Shane:

Got a few minutes.

The manual calls for 8 servos, I used 7. I only used one for the elevator.

The vertical stabs have room for 2 servos each. I put the rudder servos in the lower positions and the elevator in the upper on one of the tails. The normal connectors on a servo should make it all the way out the bottom of each vertical stab. They will go in the holes on the top of the wing. Here is where you will need 3 12" extensions (4 of you use two servos for the elevator). If you use shorter, you will have trouble making it through the wing to the fuselage. Make sure to mark them, because the will travel the same path as the aileron connectors. I used 6" extensions on the ailerons to get to the fuselage.

In the fuselage, you will need a Y for the ailerons, one for the rudders, and depending on where you locate your receiver, another extension for the elevator or a Y if you put two servos to the elevator.

I always put a short extension in my receiver, so it is easier to connect a Y to the receiver.

You will need another Y for the Y that you used for the rudder servos which will join your nose wheel servo going to your receiver.

This bird is tough to connect at the field, so I transport it assembed. I have a mini van, and plenty of room for it another plane, my tool box and my radio plus supplies.


If you need any other help, let me know, just go slow, this bird is odd.


Hank

RE: Nitro models pusher Bobcat?
 

Thats great, thanks again.. yeah I figure I better get everything I need before I get started as there seems to be a lot of head scratching on this one. Seems like a very fun plane to fly though..

Thanks again

Shane

RE: Nitro models pusher Bobcat?
 

Pit-Viper 1,
With the receiver mounted just behind the nose gear former you'll need 24" extensions for the aileron servos and 36" extensions for any servos in the tail booms. A "Y" connector will not work for duel elevator servos unless it is a reversing Y. If you are using at least a six channel receiver you won't need a Y for the ailerons. If you have 8 channels and fixed gear, you won't need any Y's at all. 6" and 12" extensions don't get ya very far in this plane. ;)

RE: Nitro models pusher Bobcat?
 

Now with extensions that long shouldn't you use a servo booster? I've read that leads any longer than I think it was 30" can start to get a weak signal.

Shane

RE: Nitro models pusher Bobcat?
 

As light as my receiver is, I saw no need to move it forward at all. I have my battery as far forward as possible, but my receiver is close to where all the servo connections enter the fuselage.

I guess I keep it as simple as I can


Hank

RE: Nitro models pusher Bobcat?
 

Thats what I will be doing as well, always try to locate the receiver where it will take the least amount of damage if possible.


Shane

RE: Nitro models pusher Bobcat?
 

Well, the 45 Super Tiger is just not enough on the Bob Cat.

It is O.K. as long as you don't have any crosswind, but I fly on grass, and the wind is near the Ohio river and changes.

Going to go to a S Tiger 75 with a 10-7 prop, that should do it. All else is fine with the plane.


Hank

RE: Nitro models pusher Bobcat?
 

No need for any type of booster. You're not using any high current servos here and even high perfomance digitals don't need any booster, just heavier gauge wire. Giant scale planes have servo leads much longer than this. ;)

RE: Nitro models pusher Bobcat?
 

As I said earlier, the 45 flew it, but no guts.

Also, read the thread on facing the fuel tank towards the engine (opposite of normal), by mistake, that is how I had the tank installed.

Never got to use enough fuel to lose suction, but I read the thread about curving tubing and putting the tank in facing the engine (backwards).

I took a piece of 1/4" copper tubing, put a curl in it, cut it as close to the curl in the backof the tank, and attached a clunk line.

The pressure tube does not matter, it just pumps fuel.

I tipped the tank, filled it then emptied it. seems to be o.k., will put it in the plane, and run the engine up and taxi around my lawn.

If that works, will fly it tomorrow. Keep your fingers crossed.


Hank