bushong572

My Feedback: (59)

I'm getting ready to fly my new (to me) YA F-15 and have a question. I know the CG should be 7 1/2-73/4" back from the leading edge, gear down, with empty fuel tanks. The stock tanks are very close to the CG. My plane has a UAT and extra hopper tank that are well ahead of the CG. I wouldn't think the designer took this into consideration. Should I balance with everything empty or with the hopper and UAT full?


Thanks

raron455

My Feedback: (38)

Full UAT, what size Hopper are you talking about you've got the two main tanks in the wing roots and then you have another tank I am assumung right behind the cockpit?

grbaker

My Feedback: (29)

My UAT is just in front of the front hatch bulkhead (between inlet and fuselage side) and I have a 28oz Kevlar tank in the front of the inlet (in the V). I balanced mine with UAT full and all other tanks empty. My forward tank empties first and then the 2 saddles.

luge_racer

Full UAT, empty everything else.

bushong572

My Feedback: (59)

Thanks for the help........I have the 2 main tanks (at the wing roots) and then a UAT and a extra tank (maybe 20 oz). Both are behind the cockpit in the "V" of the inlet sitting side by side.

So, balance with the UAT full..everything else empty???


One more thing since it sounds like I have some experienced YA F-15 flyers: at full flaps, are you running any kind of elevator mix?

Thanks

raron455

My Feedback: (38)

Yes sir keep the other tanks empty, just Uat full. And yes, you will need some elevator compensation with flaps, both take off and full flap. I run flight modes, 1 for clean flight, 1 for take off, and one for full flap, landing. Also, when you use the speed brake, be ready, it will push the plane down, nothing horrible, just be ready for it. I have over 150 flights on mine, and it truly is a fantastic stable flying jet,.hers a pic of mine, that center tank is a details4scale 52oz functional tank, and the saddles feed it. Keep the nose up on landing, and she will slow down for you.

bushong572

My Feedback: (59)

Thanks for the help............down elevator with flaps?

My plane is the exact same scheme.

raron455

My Feedback: (38)

Its a great scheme, always a big hit at the field, don't fly it in an overcast sky or late evening though, it will disappear on you.

Yes sir, down elevator for flaps, just went and checked, mine is 4 clicks down for takeoff flaps, and 11 clicks down for full flap, I also have a 5 second timer set that slows the flaps down when they activate, so they take a full 5 seconds to come to position, that way the plane don't balloon when they come down
DX-18 radio. Hope this helps,
Ronnie

Shaun Evans

Ronnie,

Nice looking bird! You say the saddles feed the slung-under tank? Your external doesn't empty first? Anyway, the pic caught my eye because I've never seen any of mine have a nose-up attitude like that with the stabs in that deflection.

raron455

My Feedback: (38)

Shaun, the 2 saddles feed the belly tank through a parallel setup, figure its easier to keep the 2 mains even feeding that belly tank, instead of that belly trying to keep the 2 saddles even. Works very well, saddles drain even. Yeah thats odd in the pic, the stabs look level, maybe pic taken as I was letting off the stick to let it come down a lil. Heres another pic of it taken a couple months ago at apache pass and the stabs are up a little more.

ww2birds

My Feedback: (14)

Boy is that good advice about visibility of the gray on gray camo .. mine met its end that way when I lost orientation in a turn, pretty far away on a hazy summer day. It was a good plane. I also had the D4S wet belly tank, though I had it drain first... then the stock saddle tanks.

You can get into a bit of an "arms race" with this plane if you put too much power, need extra fuel, have extra weight .. etc. It's a smallish jet and it can get piggy pretty quick if it's heavy. If I had it to do over I'd probably try for a smaller motor (I had a 160 in mine), and a super-light build. Easier today with the latest motors that are smaller/lighter.

One item to consider .. if after flying it a little you find the ailerons to be soft when slowing down, you can mix in some "taileron" at full flap. Did wonders for crisping up the roll axis on final approach on mine.

Dave McQ