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SIG 4*120 ARF

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Old 06-20-2012, 07:26 PM
  #1
acdii
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Default SIG 4*120 ARF

I just picked one up and plan to install my DLE20 in it. Since the DLE is out of another plane, I already have a tank setup for it that happens to be the same size, which is good, Ican use the one from the ARF in my other plane the DLE came out of.

For starters I am thinking of using Futaba s3010 servos for the ailerons and high torque MG servos for the tail, and an S3004 for the throttle. Any problems with the 3010's for the first few flights? Eventually I will pick up another pair of the servos I got for the tail when I have more cash for them.

Would there be any issues inverting the DLE20? Where would be a good place for the ignition?

Where would be the best place to install the fuel dot, and switches, and any recommendations on mounting the fuel tank and batteries?

Would using flaperons be good? Where I fly the field is surrounded by a corn field on three sides, and making a landing over the corn would have to be spot on or there would be little runway left to stop. Had to make a downwind dead stick the other day, ran out of runway. Iwould like to be able to drop right down once past the corn, so would that work?

How will it fly with a MAS 16X8 prop?

Does it fly well with a magnum .91 4 stroke? The DLE was originally purchased for a Top Flite GE P-51 which is still being built, and it may go into it when it is ready, so for a backup I have a .91.

I think that pretty much covers all my questions.
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Old 06-21-2012, 04:27 AM
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Default RE: SIG 4*120 ARF

The DLE 20 is a snappy engine in my 60 sized Sig P-51b (search youtube Sig p-51b w/dle 20 for video) but I think would be just addiquate for flying the Four Star 120. I have a kit built Four Star 120 w/ an evolution 26 GT that is good for sport flying but falls short on virtical performance and it has clipped wings (sorry, no video).

For your servo selection go a bit better on the throttle. I used a F3004 on a gasser once... vibration killed it. At least that's what the experts said.

The DLE 20 runns great inverted. See video referenced above keep in mind this was the first flight and running rich. I placed the ignition behind the fire wall. in front of the fuel tank. I guess that could be pretty spectacular should I get a leaky tank stopper or crash just wrong now that I think of it but I did not see an option at the time.

I ran my fuel fill line out of the fire wall and have it flopping in the breeze but a fuel dot right on top and behind the firewall might be sharp looking... unless it leacks on the ignition modual behind the firewall... then we are back to 20 seconds of spectacular.

I would skip the flapperons. The plane is floaty even with clipped wings.

How will it fly with a 16x8? take a video and show us I think I am using a 17x8 APC with my 26cc and would probably be better with a 16x8. My video referenced above is a MAS 15x8 I changed it to an APC 14x10 and it slowed down and lost virtical performance so I will go back to the 15x8

A .91 four stroke is a replacement for a .60 size 2 stroke. This will not get the 4* 120 off the ground without a strong head wind.

Give us an update as you progress
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Old 06-21-2012, 04:28 AM
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Default RE: SIG 4*120 ARF

I have two Sig 4* 120 arfs ( and have had one that has crashed. Another was bought as a source for parts for the flyer.). I love them . They are wondeful planes. Fly like a dream.

I used to have a OS 120 four stroke in it .But when I put a saito 120 FS in it it and it came alive. IMHO the planes needs and can easily handle the extra power.

I have 2 DLE 20 and two DLE 30s. The 20 is less powerful that my OS 120 FS.

An OS 90 four stroke is roughly the sme power out put as a 2 stroke 60 and so the plane would be severly underpowered. It would fly , but not be as interesting and satistfing.

I think would also be a step backward in performance.

The installation should be no problem . The 20 is a beam mount engine and it should fit right nicely.

Watch the balance very carefully and make sure to reinforce the firewall well .

The arf version is not available any longer . I wish sig would sell it again and come out with a gas version.

I will try to answer any additional question if I can.
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Old 06-21-2012, 09:09 AM
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Default RE: SIG 4*120 ARF

Thanks. The DLE was mounted in the Dewey so basically going to transfer the setup from the Dewey to the SIG. I used a Hitec servo for the throttle with a Goldenrod for the pushrod, with the motor running at various speeds the vibration transfers to the servo were minimal. 

Should I place the tank above the CG? Looks like it will fit in that bay above the wing.   I looked at the 3004 servo, just shy of 60 oz at 6 volts. IOW for leisurely flights they would work.  The S3010's will work fine, 90oz at 6v.  The manual says use 60oz servos for the ailerons, so all set there. 

So I need to get a 36" extension, 2 12" extensions, would I be better off hooking the ailerons to their own channel, or Y them together?  I also need a fuel dot and charge switch, would be nice if I could hide them.  Do those lengths work, or will they be tight? 

Any suggestions on a muffle for this? That stock one is pretty loud. 
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Old 06-21-2012, 12:03 PM
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Default RE: SIG 4*120 ARF


Quote:
ORIGINAL: acdii

I just picked one up and plan to install my DLE20 in it. Since the DLE is out of another plane, I already have a tank setup for it that happens to be the same size, which is good, Ican use the one from the ARF in my other plane the DLE came out of.

For starters I am thinking of using Futaba s3010 servos for the ailerons and high torque MG servos for the tail, and an S3004 for the throttle. Any problems with the 3010's for the first few flights? Eventually I will pick up another pair of the servos I got for the tail when I have more cash for them.

Would there be any issues inverting the DLE20? Inverted is "normal" for a gasser. Where would be a good place for the ignition? Any place it will fit.

Where would be the best place to install the fuel dot, and switches, and any recommendations on mounting the fuel tank and batteries? Fuel tank can go wherever you want: the carb is a pumper.

Would using flaperons be good? No. One of the outstanding characteristics of the 4 Star design is its slow flight capabilities. If you can't fly a 4* slowly, consider some other hobby. Where I fly the field is surrounded by a corn field on three sides, and making a landing over the corn would have to be spot on or there would be little runway left to stop. Had to make a downwind dead stick the other day, ran out of runway. Iwould like to be able to drop right down once past the corn, so would that work?

How will it fly with a MAS 16X8 prop? It will be OK, but 17X6 will be better if you have the ground clearance.

Does it fly well with a magnum .91 4 stroke? No. The 4*60 flies well on a .91 four stroke. The DLE was originally purchased for a Top Flite GE P-51 which is still being built, and it may go into it when it is ready, so for a backup I have a .91.

I think that pretty much covers all my questions.
Good luck.

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Old 06-21-2012, 01:12 PM
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Default RE: SIG 4*120 ARF

Had combo. Flew great.



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Old 06-22-2012, 10:06 AM
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Default RE: SIG 4*120 ARF

Nice looking model. Can anyone tell me if it is possible to build the kit version of the 4 Star 120 with a two piece wing like the ARF version.

Karol
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Old 06-22-2012, 10:17 AM
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Default RE: SIG 4*120 ARF

Started assembly last night, but since I didn't have the extensions, I didn't get very far. I also found out I needed longer servo arms. so I picked some up, thankfully the LHS actually had them in stock, almost bought the wrong one, I thought they had 2 bags of the same ones, but after I looked closer, just as I checked out, discovered the second bag was a 673, smaller arms for the Futaba, but the label on the package was the same.  Turns out the package has 2 each in it, so I'm good. The Hitec servos I got for the tail came with the correct length arms. 

I also broke down and got a CG balancer, and a throw gauge. Might as well have them now since I will need them with this plane.  Also got the extensions I needed, as well as two switch harnesses and the charge jacks to mount the switches outside of the plane. 

The only thing I dont have is a muffler. I dont like the stock one, too loud, and looking at the plane above, I really dont want to cut the cowling to make it fit, so I found a Pitts style on Milehigh RC site that I will get. 

So far liking the ARF, looks like it is well built, and I like the servo mounts for the wings, pretty neat.  Once I'm done with this, I will have a good understanding of the Pull Pull rudder so I can install that on my Dewey and not worry about the stinking pushrod that failed. 
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Old 06-22-2012, 10:20 AM
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Default RE: SIG 4*120 ARF


Quote:
ORIGINAL: karolh

Nice looking model. Can anyone tell me if it is possible to build the kit version of the 4 Star 120 with a two piece wing like the ARF version.

Karol
I haven't seen the kit, but if you make the center rib twice, get an aluminum dihedral brace, and build the pocket for it, I dont see why it couldn't be done.

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Old 06-22-2012, 10:36 AM
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Default RE: SIG 4*120 ARF

I plan on making the wing flat without any dihedral so no need for a alum. brace, only a wing tube in each half and a wing joining rod.

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Old 06-22-2012, 11:07 AM
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Default RE: SIG 4*120 ARF

Make the tube strong though, there will be a lot of stress on it, which is why the ARF has an aluminum brace.  When you epoxy the wing halves together and tape the joint with glass, all the stresses are transferred across both wing halves through that joint, when you have the 2 halves, the only thing that carries the stress is the joiner and the dowel pin at the rear.  I would use a CF tube and aluminum rod for the joiner. That should make it very strong and not add too much more weight.  Use a large dowel at the rear of the wing, or even a metal pin if you can locate one.  The front tab on each half and the hold down bolts keep the wing together and secure to the plane.   GL with the mod.
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Old 06-22-2012, 12:04 PM
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Default RE: SIG 4*120 ARF

Can you show a picture if possible of the alum wing brace.

Karol
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Old 01-31-2014, 05:30 PM
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I have just purchased a four star 120 ARF and the aluminum metal dihedral brace is missing. Would you happen to have one from your previous planes mentioned in the thread that you would be willing to sell?
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Old 02-01-2014, 07:07 AM
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Quote:
Originally Posted by pigs View Post
I have just purchased a four star 120 ARF and the aluminum metal dihedral brace is missing. Would you happen to have one from your previous planes mentioned in the thread that you would be willing to sell?
I am going to be restoring the one that blew apart later this year, so going to need that joiner. What I can do is measure it for you and you could probably make one up from plywood. In fact, it might be a better solution if its the ARF like what I got.That Aluminum one beat against the spars in flight and stressed the joints to failure.

Are you planning to have it as a two piece, or could you transport it as one? If you can join it permanently, then you will have a very low chance of it breaking like mine did. Other than the wing failing, the plane is awesome, and a very nice kit, I like the canopy on it better than the one in the box of wood kit and wish I could get a couple more.
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