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RE: Nitro models pusher Bobcat?
My question is if I "Can" test fly my Bobcat with a 46FX engine or is it too risky because of lack of power?
Thanks. |
RE: Nitro models pusher Bobcat?
ORIGINAL: caiman My question is if I "Can" test fly my Bobcat with a 46FX engine or is it too risky because of lack of power? Thanks. |
RE: Nitro models pusher Bobcat?
Thank you very much for your comments, I will wait until I install a bigger engine before flying it.
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RE: Nitro models pusher Bobcat?
ORIGINAL: caiman I installed just one screw and blind nut on each wing, between the antirotation rod and the big tube used to attached the wings to the fuselaje. The problem is that I had to enlarge the antirotation rod holes on the wings a little bit since otherwise the wings were not parallel to each other and the airplane would bank as if you were applying ailerons. My concern is if one (well tighted) screw would be enough to prevent the wings from rotating (due to the enlarged antirotation rod hole). About the 46FX engine, do you think I would risk stalling the airplane with that engine, or the lack of performance you talk about is more like for very fast flying? I hope my explanation was clear enough. Thanks. |
RE: Nitro models pusher Bobcat?
ORIGINAL: tizer33 Dont suppose any one knows the hole spacing on the exhaust port for the OS75ax? I checked there website but they dont list it. Tim |
RE: Nitro models pusher Bobcat?
I have the bobcat 50 and wondering ifthe evolution 60 will be enough power to fly this plane? Also wondering if the the engine mount needs to beef up or does the orginal work fine? and lastly, i was thinking about using one HT servo for the elevator versus two?
Other thoughts or comments |
RE: Nitro models pusher Bobcat?
My 520W1 retracts arrived today, 19 days after ordering. Along with a few other small parts (props, etc) they cost me $168. Shipping came to $31, and excise duty (miraculously!) was $0. So a total of $199.
I've never used these things before. How are they attached? Self-tapping screws directly into the wood rails? Or machine screws through into blind nuts behind? I like the sound of the second option best. |
RE: Nitro models pusher Bobcat?
I have an OS Surpass 70 engine, do you think it would be fine for the Bobcat 50?
I know the best is to use two stroke engines for this kind of fast airplanes, but just want to know if anyone has used a four stroke? Thanks. |
RE: Nitro models pusher Bobcat?
Thanks Stickjammer :)
I already got the pipe to fit a 37mm exhaust hole spacing so that makes my choice for me - 55ax. Its the weston pusher pipe should work out ok i hope. I have got to get the front retract installed yet but am waiting to pick up a cheap nose leg as the local model shop want £47.50 or $90ish for robart one. Is a micro servo like the Hitec hs65mg ok for steering? Tim. |
RE: Nitro models pusher Bobcat?
Ive just purchased a Bobcat 50 in Thailand - I payed 3'500 baht which is approx. $100 USD - I have started to build the bird after spending nearly 2 days reading this massive thread for good advise. I will be fitting the 301 retract system and I have a .46 size western UK racing engine for the power plant with Western UK racing tail pipe. Not sure if it will work but if it seems not practical I shall install my backup OS55AX. Im going to have a go at installing single servo for elevator, as it looks like a simple and effective conversion. This is my first jet type pusher plane and im hopping it will be a good introduction into model jets.
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RE: Nitro models pusher Bobcat?
ORIGINAL: amcleod My 520W1 retracts arrived today, 19 days after ordering. Along with a few other small parts (props, etc) they cost me $168. Shipping came to $31, and excise duty (miraculously!) was $0. So a total of $199. I've never used these things before. How are they attached? Self-tapping screws directly into the wood rails? Or machine screws through into blind nuts behind? I like the sound of the second option best. Wood screws are fine. |
RE: Nitro models pusher Bobcat?
ORIGINAL: tizer33 Thanks Stickjammer :) I already got the pipe to fit a 37mm exhaust hole spacing so that makes my choice for me - 55ax. Its the weston pusher pipe should work out ok i hope. I have got to get the front retract installed yet but am waiting to pick up a cheap nose leg as the local model shop want £47.50 or $90ish for robart one. Is a micro servo like the Hitec hs65mg ok for steering? Tim. Depends what you're flying from. I would not use a micro servo for grass as the nose wheel has the potential to easily strip the gears. |
RE: Nitro models pusher Bobcat?
ORIGINAL: Stick Jammer ORIGINAL: tizer33 Thanks Stickjammer :) I already got the pipe to fit a 37mm exhaust hole spacing so that makes my choice for me - 55ax. Its the weston pusher pipe should work out ok i hope. I have got to get the front retract installed yet but am waiting to pick up a cheap nose leg as the local model shop want £47.50 or $90ish for robart one. Is a micro servo like the Hitec hs65mg ok for steering? Tim. Depends what you're flying from. I would not use a micro servo for grass as the nose wheel has the potential to easily strip the gears. |
RE: Nitro models pusher Bobcat?
Original: KnowCrashes
We had trouble even using standard Futaba 3004 servos on the nose wheel. Just didn't have the power to turn the steering arrm to the nose wheel. We used a JR 126oz servo. Don't remeber the model # off the top of my head though. We have a second 'Cat under construction and will try a JR DS821 on that one. |
RE: Nitro models pusher Bobcat?
so would you say any metal geared servo of 4-5kg torque should do it.
I do fly off of grass but its a local turf field so you cant really get much smoother except bowling greens ect.. i am however heavy at landings. Tim. |
RE: Nitro models pusher Bobcat?
Caiman.......
I have about 25 flights on my Bobcat with the 46 ax. It flies the model just fine, but in saying that if I had to do it over again, I would put a 55 on it... Mine does not have retracts.. |
RE: Nitro models pusher Bobcat?
Ok, thank's. I just bought a 55Ax to install it on my Bobcat.
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RE: Nitro models pusher Bobcat?
ORIGINAL: tizer33 so would you say any metal geared servo of 4-5kg torque should do it. I do fly off of grass but its a local turf field so you cant really get much smoother except bowling greens ect.. i am however heavy at landings. Tim. I don't think metal gears are really necessary but a standard size servo would be much better than a mini. |
RE: Nitro models pusher Bobcat?
I've read through the entire thread, but I haven't seen anyone post their results with a bobcat using a heli engine. I'm planning to install a tt .50 pro heli engine on mine. Does anyone have any experience to relate? keep the thread rolling....:D
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RE: Nitro models pusher Bobcat?
Heli engines have better cooling than airplane engines, the problem might be that they are optimized to run at half throttle most of the time. But I think it might work well anyway.
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RE: Nitro models pusher Bobcat?
ORIGINAL: AGR413 I think you guys need to relax about the engine choice/speed deal. I used a doppler program on my original bobcat video and found the top speed to be 108 with a still breaking in engine set very rich on a 12x6 zinger. I have since put on a pitts muffler and switched to an 11x7 APC and it is much faster now. BTW my bobcat is without retracts. Others have mentioned the limitation for speed on this airframe has more to do with the airframe not the engine. This is by the way a tower .75. I have done the math earlier in this thread look for yourself. Yup, the T.H. 75 or the GMS hauls on this thing. Since I've switched out to an 8 pitch prop the jet guys have been very impressed with my little "cat". |
RE: Nitro models pusher Bobcat?
ORIGINAL: Stick Jammer That's odd. A 3004 should have plenty of power for the nose wheel especially since it doesn't need a lot of movement and that gives the servo quite a mechanical advantage. While 45 degrees or more of stearing rotation in each direction is NICE, it is not needed to fly this plane |
RE: Nitro models pusher Bobcat?
Another question for you all does the engine need any side thrust?
Nearly finished now think its gonna be a heavywieght with the retracts. Tim. |
RE: Nitro models pusher Bobcat?
I just aligned my engine with the motor mount plate as indicated.
I do not see a need for any additional side thrust. The plane tracks well. I think mine came in at over 9lbs. |
RE: Nitro models pusher Bobcat?
Thanks,
im going to run it see how we go on full throttle for the down thrust but i shall fit it like indicated first 9lb thats a tad over 4kg , i shall have a wieght soon:) Tim. |
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