Keith

Please list all servos you're using and where...

The Hitec 5245s are merely 76oz of tork--I don't think that's enough for flying upwards of 200-mph...

Thanks...

Mr DJ

Joe,
The boat tank should fit in between the main tanks without any modification. On my Tam's, this tank wil empty first and no trim change through out the flight. 2 liters of fuel simply isn't enought for either the P60 or P70 (I measured the tanks and they are exactly 1000cc each). I have the P60 in my Tam's but the FEJ will have the P70 in the conventional location for mor power.
Mr DJ,
I use Troy Built Lithium Ion on all mine. I have a Duralite HD regulator with built in switch harness and a single 5200mA. For elevators, the 8611A fits perfectly in the cut outs and they are only 95 bucks at Troy Built, JR DS9411's for ailerons and a DS168 for rudder.
Regards,
David

Kool Beans, David

I too use TBM LiIon. I guess for starters I’ll use just one 5600 batt/switch/reg.

Matching those JRs to Hitec, I guess I’ll go with 5599TS for elevators—5597TS for ailerons—and the DS168 for rudder. I guess a wing servos is required for the rudder—Hitec’s wing servo has less tork than JR’s.

Once my bird arrives, I’ll know for sure about the boat tank and/or the two separate 10oz tanks. If the two 10oz, may use one for fuel and one for smoke, but 10oz of smoke may not be worth the added weight.

Mr DJ

How many servos are there total?

1 Rud
2 Ail
2 Ele
1 Nose Steering
1 Gear
1 Gear Dr
1 Brake

I’m thinking the gear doors open/close off the same servo actuator with a sequencing valve—eliminating a gear door servo—correct?

Mr DJ

David,

Have you tried it? On my F-16 that space between the main tanks, measuring from the back of the canopy flange to the front of the engine hatch flange is 5 1/8". The boat tank is 5 13/16" long, so it won't fit without modifying something. I'm not willing to carve into the flanges or inlet to get it in there. It might work if you take a heat gun and collapse the top edges on the front and back of the tank a bit. I might try that if I don't come up with a better alternative.

Two 10 oz. Dubro, two 10 oz. Sullivan round or rectangular tanks, or one 12 oz. Sullivan rectangular tank will fit there.

DJ,

76 oz.-in. of torque is enough for the ailerons, assuming you have your linkage set up properly.

Joe

Joe

At or near 200-mph and all is needed is 76oz for ailerons--come on--surely a minimum of 100+

Mr DJ

DJ,

You are correct on your servo count. There are a number of ways to do the gear and doors. If you use a UP3 valve, which pneumatically sequences the gear and doors, you can eliminate one servo. Another way to eliminate the door servo is to use a button valve to close the doors after the gear is up.

I had a Jomar electronic sequencer that I was planning on using. So I set it up with separate servos and used the supplied air valves. After hooking everything up I discovered that when the gear is down and I turn on the radio, the servos would jump to the up position then back to the down position. So I nixed the sequencer.

My solution was to mix an aux. channel (for doors) to the gear channel, then use the servo slow feature of my 9303 to sequence them. Now with gears down and doors open when I hit the up switch the gear servo moves at normal speed to retract the gear. The door servo slowly moves to the close position allowing the gear to be tucked away before the doors close. When I select the gear down position the door servo moves at normal speed to immediately open the doors and the gear servo slowly moves to the down position.

Joe

Kool Beans on the UP3, Joe...

That's what I have on my YA F-15. Now, back to the aileron servo. I guess I’m thinking on terms of flying giant scale props doing 3D etc. You definitly need high torque/tork servos on all surfaces, especially rudder. But it still seems logical that if I’m flying at 200-mph, high tork servos are needed, for that’s a lot of wind pressure to deal with. I will still go with the higher tork.

Mr DJ

Nope! I wouldn't recommend anything less than that, but I would have no problem using those on this plane. Because high powered digital servos are now available a lot of guys tend to use 2 or 3 times the torque than what was the norm several years ago. Also overpowered servos are good for those that don't know how to properly set up their control linkages. I normally shoot for at least a 2:1 mechanical advantage. That means 76 at the servo is 152 at the control surface.

Joe

Joe

Teach me that 2:1 trick right now--one never stops learning...

Mr DJ

The UP3 valve is nice. When I saw that the price had gone up to $115 I decided to use what I had.

Servo selection also depends on what type of flying you are going to do. If you want to do knife edges then you need a powerful rudder servo. A lot of ARF's, including the FEJ F-16, only have room for a thin wing servo in the rudder, which is fine otherwise. If you are going to be doing wild 3D manuevers at high speed then you need more torque on all surfaces than you would for more normal flying.

When you set up your linkage you should use the hole on the servo arm as close in as you can. Conversely at the control horn use the hole furthest out that will allow the desired travel. For example if the servo connection is .5 inches from center and the control surface connectiion is 1 inch from the center of rotation you have a 2:1 mechanical advantage. The servo will travel 2 degrees for each 1 degree of surface rotation, and the torque at the surface will be twice what the servo puts out, it's simple leverage. Also in the neutral position the control rod should be 90 degrees to both the servo arm and the control arm to maximize leverage. There are space or other physical limitations that dictate how far you can go with this but you should always try to be close in at the servo and far out at the control horn.

Joe

Ok, I’m with you. I’ve set planes up like that before, not knowing that the tork was increased—didn’t care about it ‘cause I always used high tork servos. But I usually set them up just the opposite where space allowed—furthest out on the servo and closest in on the surface arm/horn/whatever.

Won’t be doing much 3D—mostly into speed and veritical blurring [sm=spinnyeyes.gif]

Mr DJ

on both my A-4s i use JR DS3421's at 65 oz/in, i use them on all flying surfaces but the flaps, with the left stick in the ON position the P-70 pushes it easily to the limit and the servos work flawlessly, you don't need brute force, you need quality and precision along with proper geometry at speed.

A P60 on this bird should be fine. The static thrust to weight ratio is 14/20 = .7. My Wren 44 electric start on JHH Sabre is 7/15 (yes 15 lbs, 'cause I am using all JR821s on it) =0.47 But it won't have good vertical at low speed. Good power management is necessary. After seeing all these discussions, it seems to me that Wren 54 Supersport or P70 has the best combination of power and less weight.

Falcon is a gas hog. I had it on my F15 and it only gives out 6 minutes of flight time.

Mike

KC/Mike, thanks for the info…

I heard the Falcon drinks it like it’s alright—but the added thrust and lifetime warranty both attract me. Like I said a few views up, on a 35/40% prop, high tork servos is a must. Anyways, I’m kool with all the info aimed at me on this matter. So far, it’s the Falcon—may ease up a hair on the servos—or not [&:]

Mike, are you still in China right now—how’s the weather—it’s cold and windy here in Maryland.

Mr DJ

Hi Guys,

I just had my builders made me an extra tank for this hoggy bird! It's too cold to fly, but not too cold to come up with something neat. That tank was made originally for my Sabre but it fits quite nicely, and holds 22.5 oz of fuel. Now, I am going for a P80.

By the way what's the volume for the 2 saddle tanks?

Mike

Mike,

That tank looks like it overhangs the equipment tray by a couple inches. As long as you allow for that it should work fine. I'd be interested in one except my tray is already done and I don't want to redo it. Maybe your guys could come up with one that just fits in that space between the mains, about 5 in. X 4 in. X 2.5 in. I'm sure several guys would be interested if the price was reasonable, either for extra fuel or smoke. I'd like about 16 more oz. for my Supersport.

The saddle tanks are one liter each. I measured them.

Joe

Thank you joe.

I pulled out the tank by a few inches just for the photo shot, It can be tugged in just enough to leave the cork out for fuel line.

If anyone is interested in this tank, just send me a PM, I will see if my builder has spare time to make a few more of these. I will just make the tanks that fit with sullivan rubber stoppers, so you can get the stopper from your local hobby stores. I don't like these Chinese made stoppers because they are too hard. Send me $10 bucks for shipping and handling for each tank.

Mike

Mike

There's still room for a UAT with this added tank--correct?

Mr DJ

Mike,

Please post the tank dimensions LxWxH.

Thanks,
Joe

Mike
How much for the tank? Shoot me a PM with your address and I will put a check in the mail for you!
Regards.
David

Hi Guys,

I am also working on a set of functional airbrake. I figure that there is an enough space behind the elevator mount. Any suggestions and inputs are welcome.
Could you all give me some feedback and ideas? Any pictures of the real one?

Mike

I was planning a Super bee in my FEJ F-16, but not if its going to end up close to 20lbs. That's considerably heavier than a SM F-16 isnt it? I ordered the Tiger meet with the gear and doors installed. If I cant come up with the funds for a merlin 90 or SS, someone will be getting a really good deal on an FEJ 16

Cody

how good a deal?

I wouldn't get too wrapped around the axle amigo about the weight amigo. The bee is around the same thrust as the P60 and I'm sure that'll propel it just fine. the 60 pushes my A-4 along with no problem after the first lap.

Cody,
Relax, the bee mounted in the tail will be fine. Like Buck said, we are flying 19.5lb A-4`s with center mounted P-60`s and getting reasonable good performance even with tailpipe thrust losses. I have the AV F-16 coming and plan on using a tail mounted P-60.
V..