opjose

The up/down thrust is fine, if you align the engine with the mounting plate.

Thai-fly

I am also based in Bangkok so was wondering where you fly and where you purchased your Bob Cat?

HobbyHut-RC

Thai-Fly - Ive been flying at several location, but right now im only flying at Khubon 40 in Ramintra. Its a nice little airfield and just had a new surface on the runway. Its easy to get there and there is lots of shelter from the sun and plenty of parking with no walking involved. I bought several Bobcat and have 2 spare - If you would like one feel free to call me on 0861650025 - Greg

Thai-fly

Thanks Greg will be in touch as soon as I get back from Manila. I was also wondering if the place you purchased the Bobcat from had any of the other nitro models kits. Am interested in the Seawind float plane as well.

tizer33

how close can the prop tip be to the wing edge? using there measurement i dont have a much of a gap at all. plenty of ground clearance though with a 11x7. Thanks for the help.
Tim

Stick Jammer

Mine is pretty close, probably 1/2" or so. I do think this adds to the noise factor on this plane, it's by far the loudest two cycle I own with a stock muffler.

caiman

My Feedback: (1)

Hi Opjose,

Regarding the Bobcat 50, I have the retract version so it came with the landing gear holes (for storing the wheels) already cut. The question is, how can a make the model have a positive angle of attack (front wheel higher than the main gear) if the holes for the wheels ar already there? if it were a fix gear airplane it would be a matter of just making the front landing gear higher, but in this case if I do so the landing gear won´t be able to retract properly.

The other question is, where should the aileron and rudder travel should be measured (on the widest, the middle, or the narrowest part of each control surface)?

Thanks.

HobbyHut-RC

Caimen - You could get a taller strut and the nose wheel or if it will fit in the undercarriage you could fit a larger size wheel.

caiman

My Feedback: (1)

I already changed the front wheel for a larger one and the main wheels for smaller ones. I cannot increase the lenght of the front strut or the wheel since when retracted it wouldn´t match the position of the hole where the wheel is stored. I guess I will try to fly it the way it is now.

Could you tell me about the aileron and rudder travel, where exactly should I measure it on teh control surface?

Thanks.

Thai-fly

I will be back in Bangkok today. Do you still have the Bobcat kit for 3500 Baht? I will take it if you still have it.

rhungent

I would NOT recommend flying with a 46. I mounted a ThunderTiger PRO 46 and it flew; but was a bit sluggish. Struggles too much against the wind. Does not climb very well at all. Don't even think about trying a loop. Due to pilot error, I banked and flew it up a 60 degree climb (sun blocked my view). Before I knew it, bobcat stalled and could not recover....complete loss. (I am getting nitroplanes redbull 540T before getting experience back up to fly the jet.)

I would strongly recommend what others in this thread are recommending and having sucess with. OS55, Tower75...
Richard

opjose

I guess it depends upon WHICH .46 you use.

I flew mine with the Tower Hobbies .46, and it flew just fine. Not sluggish at all.

However it is NOT a speed demon with this size of an engine. In spite of that the plane easily topped 55mph and did well ( but NOT unlimited ) on verticals using a 10x7 3 blade pusher prop.

Pit-Viper 1

My Feedback: (12)

That's strange you say that about the TT46pro. I had one on a trainer/sport plane and I actually thought it was a very good motor. I only had 7 flights on it when it found a new home in the bottom of a nearby swamp,, lol I was chasing seagulls with my son on trainer box and lost the signal. I thought it was a very good motor for having such little time on it. I am defiantly getting another one for the trainer I'm working on now, PT40 w/ 0% dihedral in the wing. It actually reminded me a lot of the OS.46 in appearance and reliability.


Shane

waltjg

Hello Everyone!
Have been watching this thread for awhile now, and would like to get one of those yellow Bobcats, but they are sold out "temporarily".. Anyway, had a question, was thinking of ordering that gms 76 but got to looking and it is the same weight, and the same physical size as a .91. So has anyone put a 91 in this plane? Any thoughts?? Guess I don't mind purchasing an engine, but really dont want to end up with an engine that is undersized for some planes and oversized for others, would like to use it in another plane down the road and the 91 seems more of a "standard" size..Ohyeah,,,it would have more power too,,,but I'm sure the 76 would be plenty for this plane!.. Thanks! Walt

opjose

A .91 may be too much.

The .76 gives it unlimited verticals.

The biggest problem with the .91 will be propping the engine properly. There isn't anything that will fit AFAIK.

With the .76 I'm happy with a Graupner 11x8 Pusher 2 blade prop. I would prefer something like a 11x10P were it available for even more speed, or a 12x8P which is about the biggest prop you could safely fit.... but these do not exist.

NM_Mark

My Feedback: (8)

I had a friend put an OS 91 in this plane - and it worked OK, but he was limited by prop selection (and prop clearance between the booms). My Bobcat worked just as well with an OS 55 - better fuel mileage, and it was lighter - easier to fly and land. Lighter is better, in my eyes.

Mark

waltjg

I agree Mark, lighter is better,,, have been looking at the magnum 52, but I have several 46 sized engines now.. Have seen on here that Mag. 52 and the os 55 flies it pretty good too! thx w.

Pit-Viper 1

My Feedback: (12)

I have a Magnum.52 that I will be putting on mine. This thing turns some serious rpm's. Going to try it with a 12.25X3.75APC. When I had this combo on a twist40 it was way too much for that type plane but it would haul some serious but. Anyone have this prop they could try to see how it works?


Shane

opjose

Hmm...

Even if you are able to obtain the Magnum's maximum RPM of 18000 revs you would still only be looking at a prop pitch speed of 63.92mph which IMHO is pretty low.

You would do better with an 11x7P prop.

It wouldn't be unlimited in the verticals this way, but it should pick up a lot of speed in a dive.

z06kal

I built an electric bobcat 50 with retracts. No need for a pusher prop when you can spin the motor the other way. I spin an APC 12X12E at 11,400rpm. Pulls about 48 amps on 12S lipo somewhere around 2200 watts input power. Pretty mild power system. I guess it is equivalent to about a .91 on high nitro with a pipe. Anyway, even with this much power on a perfectly sized prop level flying speed is about 118mph radar confirmed. Unlimited vertical tho more or less. Doesn't seem to pick up much more speed in a big dive even with an 11lb AUW. This thing is REALLY draggy. The airplane will start to fly impressive at about 140-150, even at 120ish it doesn't look particularly fast. I'm still trying to figure out a motor setup that isn't too heavy that will take the plane to at least 140 unfortunately my run time will go wayyy down. Right now I get comfortable 6-7 minute flight full on it most of the time.

opjose

If you go back a bit in the thread, there are reports of around the same speed with .75 glow engines using lower pitch props.

Which makes me wish I could get a higher pitch pusher prop for mine!

That's a huge advantage with your setup. You don't have to fight to get the right prop! You can experiment as you like to obtain the best combo.

Sounds like you may be able to pick up a bit more speed too.

Stick Jammer

Two problems with this choice. The 12.25x3.75 APC is a Fun Fly prop designed for lots of torque at lower speeds and it is not available in a pusher version that I am aware of.

Stick Jammer

I don't have the Retract Ready version but I would think it should be relatively easy to cut the slot in the bottom of the fuse slightly longer to accommodate a taller nose gear. General rule of thumb for control surface travel is to measure at the widest point.

opjose

On the retract ready version there is no need to recut the openings.

I merely made the nose gear wire slightly longer and the wing wires slightly shorter.

While the difference was only about 1/8-1/4" on each, the cumulative effect was about a 1/2" which was sufficient to change the angle of attack.

Also the choice in wheels affects things.

A harder ( non foam ) nose wheel will help keep the nose from being "pressed" down during takeoff.

Stick Jammer

Original: opjose

With a slightly positive AOA the nose wheel should not be "pressed" at all unless the pilot is holding down elevator during the takeoff roll.