Hello All!
I am sorry but it has been a while since I have posted. All is well with the Aeromomentum AM15h! In July I was working on refurbishing an old hangar and finally moved the Sonex out there. Very happy that the BadAss-B has a new home to live in. I still have not received my propeller and that is no fault of Mark or Aeromomentum. In fact Mark has gone out of his way to communicate with the manufacturer and also offer insight as to other options. I originally ordered a 4-bladed 60" Propeller from Luga in January. Luga is based in the Ukraine and are citing Covid-19 as well as domestic problems within the country for the delay. I understand that but at the same time it has limited my ability to really ground test the plane and engine. Granted, I still have several more items to complete on the plane but I am anxious to taxi her around the airport. In the meantime I decided to order a 3-bladed 62" propeller with nickel leading edges from Warp Drive since we really can't be sure when/if this Luga prop will ever arrive. For the HP the engine puts out as well as the geared-drive, others have used this same Warp propeller on Rotax 914 as well as the Vikings.
The big issue with any Tri-Gear Sonex and this engine choice is the ground clearance to the tip of the prop. With the standard tri-gear front fork provided by Sonex I measured it as being a 6" clearance with the 60" prop and 5" clearance with the 62" prop. The FAA dictates that there must be a minimum of 7" for a tri-gear and 9" clearance for a tail dragger. I am not sure, but I don't think being in the experimental category foregoes this requirement, and honestly it is probably best practice as well to follow these minimum requirements.
FAA wrote:FAR 14 § 25.925 Propeller clearance.
Unless smaller clearances are substantiated, propeller clearances with the airplane at maximum weight, with the most adverse center of gravity, and with the propeller in the most adverse pitch position, may not be less than the following:
(a) Ground clearance. There must be a clearance of at least seven inches (for each airplane with nose wheel landing gear) or nine inches (for each airplane with tail wheel landing gear) between each propeller and the ground with the landing gear statically deflected and in the level takeoff, or taxiing attitude, whichever is most critical. In addition, there must be positive clearance between the propeller and the ground when in the level takeoff attitude with the critical tire(s) completely deflated and the corresponding landing gear strut bottomed.
In order to combat this slight ground clearance issue I decided to modify the front fork of my Model-B. This can technically be done with any Sonex model but I am absolutely sure the factory will not look too kindly on this post. The first step that I did was cut the forks off of the gear leg.
Then I took a 1/4" thick piece of high strength steel cut to 4"x4" and had it welded to the remaining portion of the fork/gear leg. Small gussets were added perpindicular to the airstream so that there wouldn't be any additional induced drag.
I primed and spray painted this new mount glossy black. I then mounted a Zenith CH-701 front fork onto this larger mount with AN4 hardware and painted that as well to match.
I then mounted the Zenith axle and drilled additional holes so that the wheel could be moved up or down. It worked out great and allows me to use a 5.00-5 tire on the front as well. The new larger tire is a drastic difference from the smaller Chinese tire that originally was meant for the plane.
Final product and sitting in the newly refurbished hangar.
Let me know what you think about this mod...good/bad/indifferent, I like constructive feedback.