Calling all Morris the Knife Pilots...

What prop/engine combo are you using?

Size/Pitch/Brand of prop and on what momo?

Trying a 12.25 x 3.75 APC on a 46FX and was wondering what kind of vertical to expect after break-in? (4lbs-5oz).

Neo

My knife is still under construction, but I do have an OS46FX swinging a 12.25 x 3.75 on a Magic.

The motor works on that plane. At the minimum pull the baffle out of the muffler. If you can get one, put a Tower Pipe Muffler on the OS46FX. It's a straight bolt on addition. Works Great.

I'm running an Irvine .53, Ultrathrust pipe and a 13x5 Zinger. It really likes this combo. I'm no hovering man but I got her in one today with this combo. She also knife edges well with this combo. Great climb rate and will jump off the ground. I'm in lovvve.

A 46 FX with a 12x4 APC will be a great combo... a 50 SX is also peachy if you're using heavier radio gear....

-Juhan

Neo,

Got a Jett Sport-Jett .40 running a 12 1/4 x 3 3/4
APC with the tips clipped for a diameter of 11 inches. The Jett engines like a lot of RPM. Also has better throttle response. The 12 inch diameter is just too big. These engines are tuned for speed.

Tom

TT .46 Pro w/APC 12.25x3.75 and Macs Muffler (the small black one). Works great. Plenty power. Could use some more revs. Going to try the 11x4 for more RPMs or perhaps snip the 12.25 down to 11.5 or 11.

ARF

The real question is who is running arfs and who has kits. Since the arf weighs up to a pound more than the kit. The pipe made all the the difference.

Thanks for the feedback guys!

Flew my Wild Thang yesterday and had an absolute ball! What an awesome bag o' tricks this little flyer is.

It seems to have unlimited vertical now, I can hover at about 1/2 to 2/3 throttle without too much trouble. Nail it and it climbs out of it very well.

However I don't have the "snappy" response I'd like to see in the upper range of the throttle... it takes it a couple seconds to wind out and start climbing again. I'm thinking of trying an 11 x 4 prop instead of the 12.25 x 3.75 to see if it can spin the blade up to max rpms quicker (going from 1/2 to full).

I'm a little leary of messing with the pipe since I've got my tank in the wing and don't want to screw up my fuel flow/pressure scenario (works OK as it is now).

Found hovering to be relatively easy, but feels like I need my CG moved back a little from what the plans say... you guys move yours back any?

Neo

Yes, I usually move my CG back.

The first few flights will be with the CG in the correct positions, but after I get use to the airplane, I start moving the CG back.

NEO,

Just currious??? Are you using 4.8 v batteries or 6.0 v batteries?

Also, what servo are you using for the throttle?

Changing either or both of these can help your throttle response.

4.8v batteries - Futaba 3004BB servos.

I can see the servo/linkage responding quickly enough... it just takes the momo a while to "wind up" to full rpms.

Neo

I know what you mean by it taking a while for the motor to spool up.

That's one of the reasons I am now using 6 volt batteries. More speed on all the servos. Anything to help that servo get into position quicker cuts down on the "wait for reaction" time IMHO.

Did you mention what motor you were running on the Wild Thing? I have one word and two numbers for you ... IRVINE .53

Billy,

OS46FX... not gonna change...

enough money in this thing now and it's fine with the 46...

just looking for ways to tweak it to optimum performance.

Neo

Next time. If you want an extra 1,300 rpm just get the Ultrathrust.

NEO, try an APC 11.5x4. thats what I use on my Irv 46. My 46's didnt like the 12.25x3.75 . ...gator

Without a question the best engine for this plane is a Saito 72. If you want real 3D with awesome torque go 4 stroke....

Saito .72 w/Master Airscrew 13x6 prop.

I rarely hit over about 1/3 throttle on takeoff, 1/2 throttle will go vertical like a rocket.

Hovers at the bottom end of the throttle stick travel. This is somewhat of a problem for me. My Eclipse 7 doesn't have expo on the throttle channel. Need to find a way to make it less sensitive to movement at the bottom end. One click down it's tailsliding, one click up it climbing out.

Karl

I fly the Morris Sukhoi profile; I have the os 46 fx with a full size tuned pipe turning an APC 12/4. I have unlimited vertical climb and INSTANT throttle response through the entire range, it hovers at 1/3 throttle and climb fast out of any condition. the full length prop mounts easily along the bottom of the fuse. I would not think of flying without the pipe it really makes a difference

I have flown a Knife for a long time, and I'm telling you that the 4-stroke tork is what you want. The fact that the 13-14 inch props give you a much bigger thrust tube is icing on the cake! Both of these factors add up to a much more responsive plane in the hover position. I like a y.s. 63 and a 13-7 apc. If there was a better engine, I'd buy one!! I understand Saito .72 is a good choice as well. I have the Saito .72 but its on a G.P. Extra. Haven't tried it on a knife yet. I used to think my 46.fx and Rossi had good transition untill I tried a Y.S. Don'y knock it until you try it. I'm a very firm believer now! Good Luck!!!!!

I just received a OS 50 heli engine this morning after I get off the net putting her in. Pretty much same case as the OS 46 diameter wise. Few changed in the carb from the 46. I'm putting my header & tuned pipe on it as well. In a heli I saw 3 last week that performed quite a bit better than the OS 46. Should be good, but I have a lot of time i getting very little extra gaps at the ailerons while still getting complete throw. Double checked for any slop at the push rods to stop any flutter. Using the JR 4131's there should be no flutter. We'll see Sunday if weather permits..

FYI,

I tried out an APC 11 x 4 prop on my 46FX/Knife combo and didn't like it at all. I got much quicker/smoother throttle response, but it didn't fly the plane nearly as well as the 12.25 x 3.75 APC.

It produced a much more drastic torque effect on take-off and hovering than the larger prop due to the faster RPMs I imagine. Also, it didn't have near the vertical climbing power. Instead of hovering at 1/2-2/3 throttle I need full throttle, which then made it torque roll so bad it was worthless to me. Also made the plane faster/hotter which is not what I want for a 3D fun-fly.

Now I know that the saggy "throttle response" issue was due to my larger/heavier prop selection... but that's OK if I'm getting the performance I want... which I am.

Getting better on my hover now and started doing stationery/hovering flat spins... I think I can get a climbing flat spin with a little more practice. Just about got my knife edge dialed in perfect, everything's coming together now!

Thanks for all the input!

Neo

You might wanna try the 11.5 x 4 APC prop. It it right in the middle of the two props your using... I've had really good luck with this prop on my 46.

I agree with Paul, I've had and seen great success with the APC 11.5X4 APC prop on various 46 size motors. The 46s in our area prefer the 11.5X4 over the 12.25X3.75 APC props.
I too tried the 11X4 & 12x4 zingers & didn't like them, though that is personal preference.
Kevin

...OS 46FX, APC 12.25x3.75, 15% Byron's, OS #8 plug - stock muffler, Knife ARF - hovers easily...