Has anybody put an incidence meter on the RB and measured everything. I did this a couple of weeks ago while contemplating some mods, here's what I found. All my measurements were made with a Robart Incidence Meter.

Using the Horizontal Stab as the reference, ie; Set to 0 Degrees.

1)The straight sections of the framework within the fuslage correspond to the stab, ie; they're parallel.

2)The front former and front of the fuselage are at 0 degrees or perpendicular to the horizontal stab.

3)The wing is set to 1 degree of positive incidence at the root, the wing has very little if any measurable washout.

4)The firewall has 3.75 degrees of downthrust, I measured the right thrust but I don't remember the value, IIRC it was 3 degrees.

Reviewing some of the previous flight test reports, Vampire specifically made mention of the tailwheel wanting to lift off the ground while taxiing. Some of this might havebeen due to him flying off of grass. But I also believe some of this is due to the relatively large amount of downthrust.

I am comfortable with the horizontal stab, wing and fuselage relationships but IMO I believe there's too much positive downthrust. So in the spirit of modifying and improving the kit, and to also try and get a little more speed out of the design I've decreased the downthrust and right thrust. I've set the firewall in my RB for 2 degrees downthrust and 1.5 degrees of right thrust. Some might wonder were I came up with these values as a starting point. I got them from some notes I have kept from various .60 size warbirds I've built over the years. The engine mount provided in the RB kit lends itself nicely to shimming with washers. I'll adjust the offset to exactly were I like it and then measure the offsets to find out what the RB really wants.

If anyone is interested in knowing why excessive downthrust can be detrimental to flight characteristics, and how it limits flight speed, I'll be happy to post my thoughts on the subject.

Rich