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Sig Four Star 20 Super Sportster Build

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Sig Four Star 20 Super Sportster Build

Old 08-02-2022, 03:25 PM
  #151  
Jwhitacre1
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After the first sanding session it's taking on a good shape. I had to change the sandpaper on the palm sander so figured was a good time to post an update. I'll do another good round on the palm sander and then fill in the gaps with wood putty.
Old 08-03-2022, 05:05 PM
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The rough sanding is totally done now and filler putty in the gaps. Tomorrow I'll fine sand then build the lower air scoop. Getting closer daily!
Old 08-04-2022, 01:38 PM
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With the lower cowl all sanded, I made up the scoop that blends the cowl and battery hatch together nicely. Once the glue dries I'll sand the rest of the edges smooth, remove the top cowl, and add screw mounting blocks. Its all little details now and that feels good to know the big stuff is done!
Old 08-05-2022, 06:15 AM
  #154  
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I used an old window screen insert for donor metal to make these vent grills. I glued them in last night and dusted white this morning to match the cowl. They turned out exactly how I wanted
Old 08-06-2022, 05:47 AM
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Rain day here so might get some good progress done on this project. So far the upper cowl is reattached and screws holding the upper/lower together in place. I'm now shifting focus to covering. The tail feathers are first so the iron is heating up now and I'm going to get at it.
Old 08-07-2022, 05:23 AM
  #156  
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It's really taking shape now! The addition of the tail feathers really gives the look that was missing. I'm guessing there's about 4.5 hours of work left on this build. I see no problem with having it ready for next weekend.

Old 08-07-2022, 07:37 PM
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I didn't want to invest time into the major tasks tonight, so I did some prep work. By I'd guess Tuesday I'll be installing the wire bracing and wanted to get the end pieces ready. There's 2 landing wires since those pass through the fuselage, and 4 flying wires. I modified some control linkage hardware I had to be my turnbuckles and electrical connectors for the other ends. Other than soldering this stuff on its ready to go. I'll clean up the clevises tomorrow with a dremmel, tonight I wanted to just get the holes drilled out for the bolts. That reminds me I also drilled out the bolt holes in the wings. The appropriate length bolts have been fitted til install time.

Old 08-08-2022, 07:07 AM
  #158  
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I have been following the thread, just have not commented. Just ain't had the gumption to.
3 years my better halve and I have avoided even the common cold, not a single sick day, Then bam Coved whacks us. But it has been fairly mild. All of the vitamins and other stuff has paid off I think. In our 70's with a bunch of comorbidities and we are doing fine.

This is going to be one darn sharp bird. Hope you can get fight video.

Ken
Old 08-08-2022, 08:29 AM
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I'm glad to hear you are both doing fine, that's great news. Hopefully it runs it course swiftly and doesn't linger around like in some people. Whatever you are doing is working so keep it up!
Old 08-08-2022, 08:31 AM
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When I get home this evening I'm going to try and do all the remaining covering amd windscreen. That'll leave just control rods and bracing tomorrow.
Old 08-08-2022, 04:05 PM
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I finally got all the covering out of the way. Feels good to look at an almost complete aircraft. Canopy, control rods, and bracing is all that is left. Getting excited now!


Old 08-08-2022, 04:10 PM
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SWEET! Heck yeah
Old 08-08-2022, 06:03 PM
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The control horns are on and fine tuned, radio all programmed, and windscreen on. All I have to do tomorrow is the bracing. Trying for Saturday maiden.
Old 08-09-2022, 06:13 AM
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Lot's of luck on the maiden.
You sure did achieve the period look you wanted in spades.

Super sharp looking bird

Ken
Old 08-09-2022, 03:31 PM
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Thanks! I'm truly thrilled how it turned out. 30s racers are my favorite subject in aviation.
Bracing is all on! That was a chore and I'm so happy I used the turnbuckle those came in handy. Between now and this weekend I need to bolt the prop on permanently and set initial CG.
Old 08-09-2022, 05:11 PM
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Couldn't make you wait to see the bracing on til the weekend
Old 08-10-2022, 08:27 AM
  #167  
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That really makes it look period and great

Ken
Old 08-13-2022, 11:23 AM
  #168  
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It flies! That said there was a few bumps in the road. The wheel pants caught a lot of grass and slowed down takeoff runs so it took a lot of runway. The lower wires also were snagging so 2 got ripped off the mounts. In the air it's an absolute rocket. It really needs speed to stay going. I flew it great at 90 perce t throttlebut got mushy at 75. Landing with flapperons was actually great so I have some alterations to make.
1. Dump all the extra weight possible
Pilot, second battery, wires, more lightening holes in control surfaces, different wheels, and no wheel pants.
2. Thrust angle is down too much and needs raised a bit.
3. Tone down the dual rates more.

To be continued...




Old 08-13-2022, 12:06 PM
  #169  
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Congratulations on a successful maiden. It is a good looking bird.

Ken
Old 08-15-2022, 05:14 PM
  #170  
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Thanks! I'm hoping today's modifications help make it a better performer.
Today I started getting this bird ready for another try this weekend.The motor thrust angle is shimmed upfront where it was. I pulled all the scale looking accessories, Pilot, and pulled the long wheel axles. The new wheels are 3" foam and use smaller diameter axles which saved some weight. I used a hole saw to put lightening holes in the elevator and rudder. The battery tray was removed, cut in half, and glued back in. The receiver was also relocated.OK now for the fun part. The new weight with a single battery is 60oz. I met my pound weight saving goal and then some. Power was sacrificed obviously due to losing half my capacity. With a 13X6 I'm now getting 450W full throttle, but with the new lower weight that's still better than before. Tomorrow I'll patch all the holes from removing everything and drilling out the tail feathers.
Old 08-15-2022, 05:50 PM
  #171  
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That is no small diet
Old 08-16-2022, 05:17 AM
  #172  
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Originally Posted by flyingagin
That is no small diet
Yeah the reality that I went way too far on the accessories to make it look great on the ground hit yesterday. That drastic of a weight shift will bring this to life I'm sure. I'm planning on taking it back out Saturday to post retrofit maiden.
Old 08-16-2022, 05:58 AM
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I bet this next flight is a whole nother plane.
I have a plane that flies good till time to land and then it is a bullet looking for the runway. I bought it 3rd hand, and the original builder just over built it structure wise. Uses a Super Tiger 3000 for power has about a 7' wingspan, I think it is about 18 pounds as it was built and radio equipped. Those old servos weigh 5 ounces each times 4. And the battery pack was over 12 ounces. So that is 32 ounces alone.

Change to modern servos and they will only weigh 1.75 ounces for more torque and speed, so only 7 ounces saving 13. And the battery will be replaced with a LIFE battery of more capacity for only 4 ounces saving 8 ounces. And 5 grams for a receiver versus 1.5 ounces. Throttle servo wont change weight at 1.5 ounces still. But just the radio change out will save 22 ounces.

I will likely build a new wing so I can move the main gear forward and get rid of the nose wheel and strut. 6 inch nose wheel and strut will weigh less than adding a much smaller tail wheel.

But I will gain some weight back as I intend to change out that fuel ($gold$) sucking ST3000 with a gas engine. Also having to add methanol to stock fuel to cut it down from 18% oil to 11% is a pain.

Also I will make a new wing that is 3 piece for easier transport. I bet I can build a new at 1/2 to 2/3 the weight of the original.

And the wing is grossly over built out of 1/8" balsa. should have been 3/32" light balsa and smaller spars.

Remains to seen if I can lighten the fuse and tail feathers. But I am sure I can knock 3 pounds off the flying weight. That should slow the beast down on final.
There are other places to cut weight.

So shaving 2 to 3 pounds or more will make for a nicer plane.

I have a Dirty Birdi that also is apt to get a new wing and conversion to tail dragger as this part of the country almost all RC fields are grass and not hard top. I have flown trikes off of grass before and found it not fun when when the nose wheel wants to dig into the grass on take off.

Ken

Old 08-16-2022, 10:25 AM
  #174  
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Ah the old 1/4 scale brick servos, yeah I've changed them out before for newer equipment. Sounds like with a gas conversion and much, much lighter equipment that you'll have a serious winner even if you don't build new wings.
The Bridi Dirty Birdy is a fantastic model. Ive never come across one as a tail dragger so would be very unique. I'd be interested to see that when you get it finished.
I hope you shed as many pounds as possible from that big plane, when you lighten the load that much magical things happen
Old 08-16-2022, 11:11 AM
  #175  
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The dirty Birdi has a glass fuse. Reasonably light. The wing is foam a sheet balsa OK weight, But I also got it 3rd hand. The guy that built it glued the plate that the retracts are mounted to just to the foam. Was never very solid. And looks to be a real pain to re engineer. And since the plane has fairly small wheels and will be on grass from no on It just seems to make sense to build a new wing and move the gear forward, add a tail wheel.
I I have piped 60 to put on it. will have to lay the engine over on it's side. That should breath some fire into the plane. Got to replace all of the servos including the retract servo, Maybe go electric retracts.

I found a pic of the big plane on an old build thread on this site. I downloaded all three so I have them again. The original muffler fell off in a cow field a long time ago. So I engineered a replacement. Better power and less noise, but ugly And wont matter when I put a gasser in the nose. I've been looking at a 35cc gasser. Those old big ST really were not all that strong for their size. So the gasser should be at least equal if not better power.

The plane will get recovered. In fabric and dope. The canopy will be replaced.

It made a great tow plane for larger gliders.

Ken






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