H9 Cub on Floats Problem
07-04-2006 | 09:58 AM
#1
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From: Chicago, IL
H9 Cub on Floats Problem
Just installed the GP floats on my 80" H9 J3 Cub and I'm trying to get the CG correct but its difficult since the floats cause a pendulum effect and makes it hard to balance. The plane hangs slightly tail down - I think - how should the plane hang when checking balance with floats? I took the airplane out for the first flight test and it seemed really elevator twitchy (tail heavy) and also wanted to roll right so I added down trim and left roll to compensate.
Should I add weight to the front of the floats? If so, are there any weights that are pleasing to the eye to use? Also, I'm using a Saito 72 and it goes through the supplied fuel tank in about 7-8 min. Is there a larger tank I can fit into this bad boy?
This is what I'll try:
1) Move battery forward under fuel tank
2) Try to get larger fuel tank
3) Add weights to floats?
4) Adjust ailerons for roll problem?
5) Add up trim on both ailerons?
Any help would be great to get this plane flying safely!!
Thanks!
Should I add weight to the front of the floats? If so, are there any weights that are pleasing to the eye to use? Also, I'm using a Saito 72 and it goes through the supplied fuel tank in about 7-8 min. Is there a larger tank I can fit into this bad boy?
This is what I'll try:
1) Move battery forward under fuel tank
2) Try to get larger fuel tank
3) Add weights to floats?
4) Adjust ailerons for roll problem?
5) Add up trim on both ailerons?
Any help would be great to get this plane flying safely!!
Thanks!
07-04-2006 | 10:43 AM
#2
RE: H9 Cub on Floats Problem
I'm sure you'll get lots of advice on this so I'll just toss this in for what it's worth....I sugget you balance the aircraft where there is no wind to eleminate the "pendulum effect".
You may want to add the weight to the floats so you aren't re-balancing the plane everytime you add or remove the floats. The most unobtrusive method is to add buckshot and epoxy to the nose of the float until it balances on the correct CG. You said "The plane hangs slightly tail down - I think", and it acted like it was tail heavy (elevator twitchy). It should balance level at the suggest CG per the manufacturer. Floats shouldn't change this. As for the up trim on the ailerons, if anything on a float plane I would crank in a little down trim on the ailerons (faux flaps). They aren't supposed to fly fast or do aerobatics, especially an 80" Cub.
You may also want to check where the step on the bottom of the floats ends up in relation to the CG. The step should be at the CG for a starting point.
As I said... just my opinion and you know what they say about opinions. Watch what a fire storm this thread starts. You have hit on at least three controversial topics.
You may want to add the weight to the floats so you aren't re-balancing the plane everytime you add or remove the floats. The most unobtrusive method is to add buckshot and epoxy to the nose of the float until it balances on the correct CG. You said "The plane hangs slightly tail down - I think", and it acted like it was tail heavy (elevator twitchy). It should balance level at the suggest CG per the manufacturer. Floats shouldn't change this. As for the up trim on the ailerons, if anything on a float plane I would crank in a little down trim on the ailerons (faux flaps). They aren't supposed to fly fast or do aerobatics, especially an 80" Cub.
You may also want to check where the step on the bottom of the floats ends up in relation to the CG. The step should be at the CG for a starting point.
As I said... just my opinion and you know what they say about opinions. Watch what a fire storm this thread starts. You have hit on at least three controversial topics.
