I posted a thread about flying my Little Tomahawk with a Norvel .049. I've been strictly using the APC 5x3 props. They seemed to work better than anything I currently had at the time. My only complaint is the cost of these little buggers. They're $4.00 a piece and I've broken several of them. I see the other threads and the different props most others are using. One thing I don't see much of is the usage of the .049. I recall seeing the majority of flyers going for the .061's. Well, I tried the APC 5.5x2 the other day and I was really taken back. I just couldn't believe the performance I gained using this prop. I'm using .012 x 42' lines and I need to go out more. My plane is also overweight as its been crashed several times. I was wondering how the APC 6x2 would work. The 5x3 is fast but it lags in the corners if the engine is pushed too hard. I just never would've imagined that this prop would even work. The other plus is that its under $2.00. Unfortunately this past weekend I came in inverted and doinked the needle valve which bent the spraybar. After chucking it up in the drill press with the needle inserted, I was able to slowly turn the chuck and find the point it was running out the furthest. I was actually able to straighten this with no binding in the threads whatsoever. I was pretty happy as these needle valve assby's are quite difficult to find. Those that are using the stock needle with the long wire that projects from it, cut it off. I could've saved myself a lot of headache had I done this early on. I believe its been mentioned on here that some have actually broke their crankcase due to hitting the ground with the long needle hanging out. Its a good idea, but bad for mild mishaps.  I'd like to know what if there are any other props that are being used on the .049. Ken

Norvel and APC engines need to run FAST!  I figure the minimum rpm on the ground should be 19K rpm.  Currently, I am running the APC .061 with the 5.5x2.5 prop on 7.5% Nitro and 45 foot .008 lines.  Seems to be a rock solid combo.  Faster flight on longer lines seem to be more wind sensitive to me.  Just an impression, so counter argument is welcome.  I am sure that .012 lines are overkill!  You will be much happier on longer .008s.

Norvel and APC engines need to run FAST!  I figure the minimum rpm on the ground should be 19K rpm.  Currently, I am running the APC .061 with the 5.5x2.5 prop on 7.5% Nitro and 45 foot .008 lines.  Seems to be a rock solid combo.  Faster flight on longer lines seem to be more wind sensitive to me.  Just an impression, so counter argument is welcome.  I am sure that .012 lines are overkill!  You will be much happier on longer .008s.

Ken,
Agree w/all Larry says.
Note: When you go to longer lines, reset your leadouts aft. Line III indicates approx. 1/8" more, actual depends on your weight, span and lap time.
Increased line drag is more noticeable on the smaller models.
Roger V.

Kenneth,

Several have mentioned that NORVEL engines (bith BigMig and AME) need to run at high RPM but perhaps it would help to know why. BTW, since the AP Wasp is mostly a knock-off of the NORVEL engines, this should also apply to it also.
 
Fuel draw is a function of the venturi's ability to create a vacuum. By using a maximum venturi as NORVEL engines do, fuel draw suffers. Since the vacuum increases with flow, RPM must be kept up, unless some type of pressure is used to compensate, such as muffler pressure or a bladder.

Additionally, the torque curve due to timing is maximized at high RPM. To achieve this RPM, a smaller prop must be used. That explains why the 5.5x2 works well.

George