Model IV gear change

[Bryan]

Does anyone know how much farther forward the grove gear is verses the stock gear? I am sure it sits a little farther forward but I need to know exactly what it is to put into the weight and balance program. I believe it will be about 1.5 inches, but this is just a guess on my part. So any of you guys that changed over to the Grove gear what changes did it make in your CG?

[HighWing]

Bryan,

Mounted, the Grove gear is nearly three times the weight of the stock gear. I called grove once and the 26 lbs they quote on their website is aluminum legs only and with the mounting brackets, axles and hardware for the IV, they come in at about 31 lbs. Since the actual center of mass on the stock gear is difficult to determine, It would definitely exceed my math capabilities to do the calculations to determine what the difference between the new and old is. When I changed out, I rewieghed the airplane.

Lowell

[Bryan]

Thanks Lowell yes I have recalculated the weights on all three wheels, however I was trying to use the old weight and balance program that I have from when I built it in 2000. It puts the arm for the mains at 3.20 and when using this as the moment and putting in the new weights, I come in near the back of the CG. I know this is not correct. If I put the arm at 1.70 which is about where I am thinking it should be with the Grove gear I come out great. This is saying that the new gear is 1.5 inches farther forward. I guess I am going to need to level the plane back up and plum down and figure this all out I was just hoping someone already had done this or it was already figured somewhere. Thanks for the help. Bryan

[HighWing]

Bryan,

As I read your most recent post, I think I have to agree with you regarding the arm of the grove gear. The old gear extended between two of the wider spaced attach points and since you have that arm, I would suspect if you deleted that weight there, and then added the Grove weight at the new arm you would be fine. My guess is - and I am not looking at the airplane right now - that the grove gear extends pretty much perpendicular to the bottom of the fuselage and that the arm would be the center of the gear leg and your calculations would be fine.

Lowell

[Bryan]

Yes Lowell I am sure it is farther forward than the stock gear. I wonder if this weight and balance program that I have has the arm going from the leading edge of the wing? I will just need to set the plane back up and do some calculations. Thanks for all your help.

[Jerrytex]

I weighed my plane today. It came in at 681 pounds. I was hoping for less but in looking at this post I saw the deal about the weight gain from the grove gear and the extra weight makes sense. When this plane was originaly built, it weighed 656 pounds. When it was rebuilt, Grove landing gear and an LP aero windshield were added so I guess it bumped the weight up by 25 pounds. Kind of a bummer but I knew I was always going to be at gross all the time anyway.

Oh and I also forgot to mention the upgraded engine mount from kitfox was was substantially heavier than the original. I guess it all adds up.