When I first put my plane in the air, I promised myself I would continue to make little refinements to make the plane the best I could afford. I had always hoped that this would be my hundred mile an hour airplane. Aviation is a hobby, and I don’t like to use my family’s retirement savings to fund my joy in life. (frankly I can’t afford to) My Aviation is done on a budget and that is part of the reason I like ultralights. With self-manuals and repairs and modifications self-made it is less expensive to keep the plane in the air. This means getting the speed performance of the 120s and the 140s at my field takes a little extra effort. When I purchased my plane as a project it came with an in-flight adjustable propeller. I wanted to get the plane in the air first without any extra issues the propeller might offer but after 75hrs on the clock I thought it was time to get it moving. Besides at this point with the prop only ground adjustable I am still the slow guy with the Savage Cub pulling back on throttle for me to keep up.

I installed the propeller with a two-blade configuration to start and did some quick tests to confirm all was good. I had heard that the In-flight adjustable from IVO has had some issues with the motor on the ultralight propeller. My thinking was the two blades would be easier on the motor than trying to force three blades though the pitch change.

I also surmised that the two blades might give a little better speed than the IVO in a three-blade configuration. I had used the two-blade configuration on my Avid Speed Wind and could see 100mph with the 582-power plant. I thought with the KitFox and a 912 100MPH should be guaranteed. I had run a two-blade configuration on the KitFox when I first put her is the air but was not satisfied that it was the best solution. The speed was good and would seem to get above 100mph, but the take offs and climb seemed to suffer. With the in-flight adjustable I should be able to overcome that issue by using the electric motor to fine tune the pitch for best take off and climb and then switch to cruise pitch once in the air. So, what kind of speed can I get with 5200 RPM straight and level?

Yep, the airspeed reads 114-115MPH How about that a 100knot ultralight, on 80horses.

That’s impressive.

With a little further testing I noted that my take offs seemed to take longer than I was happy with, and climb was not what I was hoping for. I think the propeller was slipping too much as it bit the air. I went back to a three-blade configuration and the motor seemed much happier. It runs smoother on three blades than it does on two as an added benefit. Did I lose some speed. Yes, I am back down to 105-110 but still I have a 100mph Ultralight. One of the goals I was shooting for.

BTW Mike’s KitFox with the 100HP ULS is reported to cruise at 115 and gets off the ground very quickly. His pro is ground adjustable. I know a KitFoxer in Vernon that cruises at 118MPH with his 80HP IFA Model V and another in Phoenix that can Cruise at 125 with his hundred horse and an IFA.

There are a lot of other little refinements for me to make over the next while and as I am planning a trip to Eastern Manitoba and Northwestern Ontario, some will be made before I go and some after I get back.

One of the things I must do is install a VOX intercom. My radio is an early FL760, and the intercom is switch on or PTT activated. I have a VOX intercom that will be a welcome addition. I just put a rudder trim on. I have not tested it yet but hope to make it electric controlled eventually. Same with the elevator and ailerons.

Little refinements. Seems like the fun never ends.