Is there a starting brace height for a straight limb Howard Hill style longbow.  It shoots FP fine at 7 1/4 but BH are terrible.  Tonight I pulled out all the stops and increased the brace height to 8 1/4 inches.  Is this to much?  Yes the BH fly better, Why?? Am I hurting the bow?

I brace my Hills at between 6 1/8 & 6 1/4" you're loosing a lot of performance at 7-8"
Bob

I had poor BH flight at 71/4 but it got better at 81/4 is that a fluke?  I will try it lower and see what happens.

I may be wrong, but I swear it sounds to me like you are overspined.

The bow measured 57# at 27 inches. It is 65# at 28 3/4 inches.  The arrws are spined 60 - 65 with a nock taper.  I cut them 27 inches because I was shooting with a slight bent elbow like I read you should do with a long bow.  All my recurves I shoot with a straight wrist and shoot 28 3/4.  I will try some lighter spine and see what happens.

Which way are the broadheads hitting compared to the field points, to the right? (right hander) Raising brace height shortens the power stroke and works for an underspined arrow. Also where are the field points hitting in relation to a bareshaft? What kind of shaft?

CE, Are you saying the bow gained 8 pounds by increasing the draw length 1 3/4 inches, if that is true it is stacking at the longer draw. I assume your draw length is 27 or less.

I would start back with bareshafting getting the correct spine and then tuning with broadheads. Since your arrows are already cut you may have to adjust tip weight, brace height and thickness of strike plate to get it in tune. Broadheads really bring out the affects of a poorly tuned arrow.

I bare shaft with this same arrow and FP it and the FP flew the same at 20 yards perfect. No problems  I increased the thickness of the strike plate 3/8 it got better.  But that goes against all logic.  These arrows fly fine out of my heavier bows.  But I just want to hunt with this pawn shop reject.    Where should I start with the brace ?

What weight of tips? You shot a naked shaft on 5-6 yard's? It is not necessary to hasten to reduce shafts...
Andrey