Author Topic: Jet trimming (Read 2202 times)

RC Storick · « **on:** June 19, 2006, 08:59:57 PM »

Tonight was probably the last night I would have been able to have gone out to fly before SIG. So to the field we went. The Jet trim is coming along nicely! I had taken the metal tank that Jim Cassele made out of the plane and replace it with a 8 oz clunk tank. Much better. However on yesterdays flights I had noticed it was tail heavy and I will not have that this year. So I weighed the two tanks and found the clunk to be a 1/2 oz lighter. So I added that plus a 1/2 oz of nose weight. Total 1 oz (it kills me!) and I might go a 1/2 oz more

.

After sorting the tank out and changing the fuel filter twice I have the motor run down perfect! 5% nitro and 18 inch pipe I let it go at 9100 rpm and it just chugs along at an easy clip. POWER POWER but thats why I bought the PA.75

I went through three different handles tonight until I found the one that works the best with that plane. It has a wonderful groove. Gary said my inverted flight was a 40 or damn close. Of coarse The rest didn't look that good yet but I will work on it. Only have 3 weeks to get into shape. I kinda doubt it but I'll be there none the less.

Randy Powell · « **Reply #1 on:** June 20, 2006, 12:20:00 PM »

>>So I added that plus a 1/2 oz of nose weight. Total 1 oz (it kills me!) and I might go a 1/2 oz more <<

If that kills you, wait till you have to add 1.5oz of tip weight. Ugh!

Jim Pollock · « **Reply #2 on:** June 20, 2006, 01:59:45 PM »

So Robert,

Are you going to give us the total number of pounds the jet displays\
on the scale. Ahhhh, I bet about 4 or a little better?

Jim Pollock

RC Storick · « **Reply #3 on:** June 20, 2006, 04:33:41 PM »

Quote from: Jim Pollock on June 20, 2006, 01:59:45 PM

So Robert,

Are you going to give us the total number of pounds the jet displays\
on the scale. Ahhhh, I bet about 4 or a little better?

Jim Pollock

You got it. It is 65 oz bummer but it handles it well. Next year a new and improved version will appear. (a half a ton lighter)

But this one did not turn out too bad for three weeks. If you finish them fast they weigh more.

proparc · « **Reply #4 on:** June 20, 2006, 04:49:26 PM »

Quote from: Robert Storick on June 20, 2006, 04:33:41 PM

You got it. It is 65 oz bummer but it handles it well. Next year a new and improved version will appear. (a half a ton lighter)

You can't be too thin or too rich!!

Randy Powell · « **Reply #5 on:** June 21, 2006, 08:54:35 AM »

Robert,

I was pretty happy when I finished mine. ~770 square inches and about 64oz. Not too awful, I thought. I was shooting for 60. But with 3.5oz of nose weight (how the heck did that happen!!) and an additional ounce of tip weight, it's now 68.5oz. Sigh... But like you, mine seems to handle pretty well. After some exciting initial flights where my clearly deficient bench trimming was tested, it now grooves very nice and has just blazing turns. Looks like the wing produces enough lift to carry the load alright, but like you, I'd like to build another that is lighter. Clearly I need to figure out a different structural set up for the tail to lighten it up. Seems that if I can figure a way to know 2 oz or so out of the fuse tail structure, I can dump that load in the nose and have a decently light plane. May have to add a half inch of nose length too.

Keep us posted on progress of the Jet. It's cool

Jim Pollock · « **Reply #6 on:** June 21, 2006, 05:20:15 PM »

Randy,

The secret to a light fuse is the ladder crutch method. Contact Tom Morris, he would be glad to send you all he has about the subject. 256-820-1983. When I start on the fuse for my new airlane it will be ladder crutch because it has to be, or it will weigh 68 ounces too and only have 660 Square inches of wing area.

Jim Pollock

RC Storick · « **Reply #7 on:** June 21, 2006, 06:20:17 PM »

Quote from: Randy on June 21, 2006, 08:54:35 AM

Robert,

I was pretty happy when I finished mine. ~770 square inches and about 64oz. Not too awful, I thought. I was shooting for 60. But with 3.5oz of nose weight (how the heck did that happen!!) and an additional ounce of tip weight, it's now 68.5oz. Sigh... But like you, mine seems to handle pretty well. After some exciting initial flights where my clearly deficient bench trimming was tested, it now grooves very nice and has just blazing turns. Looks like the wing produces enough lift to carry the load alright, but like you, I'd like to build another that is lighter. Clearly I need to figure out a different structural set up for the tail to lighten it up. Seems that if I can figure a way to know 2 oz or so out of the fuse tail structure, I can dump that load in the nose and have a decently light plane. May have to add a half inch of nose length too.

Keep us posted on progress of the Jet. It's cool

It's not just the tail that needs to be lighter. The whole package. Gross weight goes down CG moves forward just a fact of life.