opjose

WHAT Pitch up?

If the C.G. is correct there should be no pitchup in flight ( assuming you are running a glow engine... ).

opjose

That's because you did not have the AOA right. The default setup puts the wing angle too far down during runup, causing the long rollouts.

Downthrust should not be needed with a glow engine. Mounting the engine squarely on the support structure is all that is required.

HeliTB

Yes a glow engine, I will be using an OS 55 AX.

So are saying if I get the CG correct there will be no pitching?

TUMBLER

My Feedback: (13)

All Bobcats of any size or power system will pitch up as you increase thottle. The real one has 5-6 degrees of downthrust to compensate. You can either add down thrust or mix elevator to throttle. Trust me, I have had about 5-6 of them in various sizes haha.

opjose

I have four of them and none do this that I've noticed... ( knocks on wood... ) including the Falcon 1.20.

There is a bit of climb as speed increases but once trimed for level flight, they stay level throughout the throttle range.

I expected a bit of pitch down given the C.G., but that did not happen.

My photo gallery shows the motor mounting of the .50.

tizer33

Hi ive flown mine 3 times now but it is very hard to fly so sensitive to pitch inputs.
I got the c.g at 10.3 inches back from leading edge but is it the fuse joint or where they would meet in middle of fuse if you know what i mean?
The main problem is when turning i roll plane over grab some elevator and she's nose down before i know it . Its fine if i go big open circuits and it glides better than i thought too, its just it almost 'tumbles'? through the air with any kind of tight turn similar to a car loosing the rear
Tim.

squidster

Thanks for your observation....


The AOA is correct. Why would you want to argue with what you don't have knowledge of?

tizer33

Does anyone one know what airfoil it has or what one would be best to replace wings with?

bob092

foremost , cat , kangaroo falcon ....all look close andshould work

bob092

duplicated answer....removed

opjose

Don't speak about what you know not.


You obviously missed that I have now five of these planes so I can speak from SOME experience.


Downthrust is - NOT - needed with glow ( and electric ) engines using the standard mounting scheme.

The turbine coversion does require some downthrust.


The plane does NOT pitch up if the glow/electric ngine is mounted on the centerline.


If the plane requires an overly long run for takeoff, the AOA is - WRONG - period.

HeliTB

opjose... I tend to agree with your position. I will more than likely fly the bobcat with the OS 55 AX mounted in the centerline to see if I need downthrust. I don't want to do something that's not necessary. If my particular Bobcat needs downthrust, no harm no foul. If it doesn't need any, again no harm no foul. Thanks for the advice. Hopefully I'll maiden her this weekend if its not to hot.

squidster

You might ought to consider your own comments sir. Have you seen our set up to make the determination that you speak so pompously about? I don't think so.

I'm glad what you have works for you. What we have works for us. Oh BTW, we have 5 of these also. So I believe I am also speaking from a position of experience.... Experience with OUR planes, not your s or anyone else's.

Further, I made no comment about the plane pitching up as you suggest. I made the statement and observation from EXPERIENCE that downthrust would dramatically recduce the takeoff roll length.

Please stop by sometime if you are in Florida, you can have a look for yourself. Heck I might even let you fly one of 'em.

squidster

GEEZ, you seem to get it. Why do others not? If it works for you with or without, then GREAT!!!!!!!


Whaddaya mean to hot????

sbrackets

I need a Orange or Gray canopy to match my Orange & Gray NitroPlanes Bobcat 50. I received a Red canopy. Anyone willing to trade? The plastic bag has been opened to view the canopy but still uncut.
I contacted Nitroplanes and asked them if the Red canopy is correct. They stated that it was correct with the "NEW" batch of Bobcat's.

Thanks, Jim

amcleod

I got a red canopy with the orange/gray Bobcat too. It seems to be the standard part.

squidster

Ditto... red canopy here too.

If you want to get rid of it, you can paint it black from the inside, then it looks like it is tinted.

HeliTB

It was orange, but I painted mine yellow to match my color scheme. I will post pics soon.

Boomerang1

Well, it flys! Very fast with the Wren 44 turbine, time to put some paint on it! - John.

BillS

Got an opportunity for several flights on the Bob Cat Saturday.

I used fixed gear and a .45 OS engine (reverse rotating) on my Bob Cat and it takes 12 oz. weight on the stabilizer to rotate.

I was surprised that re-flexing the ailerons was unnecessary for high alpha landings. I was also surprised that re-flexing the ailerons slightly had only a small affect on flight attitude. Without re-flexing ailerons elevator authority at high alpha was good and without stall tendency all the way to the ground and landing roll was short.

A .45 engine might be considered a little small for the weight and wing area. Some caution to not jerk the airplane into the air is required.

Bill

TUMBLER

My Feedback: (13)

Anybody have a set of wheel wells they didn't use.....preferably gray ones, but will take what I can get.

Thanks!

Tumbler

squidster

Yep. Got wheel wells, and don't need them.

TUMBLER

My Feedback: (13)

Cool! Can I get them from you? Do you want money for them or just shipping?

Thanks!

BillS

Canard set up ready for testing.

Bill

squidster

Just shipping. I don't need them, doesnt work very well with the retracts. Send info and I'll get them out to you $5.00 should cover the shipping.