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-   -   Sig Four Star 20 Super Sportster Build (https://www.rcuniverse.com/forum/kit-building-121/11695978-sig-four-star-20-super-sportster-build.html)

Jwhitacre1 12-29-2021 03:36 PM

Sig Four Star 20 Super Sportster Build
I'll let anyone reading this know that this build is Severely off the beaten path from stock. The premise is making a 30s era racer from this kit with a lot of mods and extra balsa. Think Ryan ST-A and Gee Bee D had a baby...that's the route this is going. So to get this kit ready for the 1937 Cleveland Nationals a few things needed changed: wing tips rounded, all new tail feathers, bigger ailerons to cheat longer chord, fatter fuselage to accommodate the bigger motor/battery combo, and most importantly open cockpit for my "pilot". New landing gear are being added also since this is a much bigger bird than intended for the stock ones.
So I will let you know this build is half done and got shelved in July. That is ok because the fun parts where it all comes together begins! The wing and fuselage are mostly framed up with some minor stuff needed. Tail feathers need built and all control rods/servos added. Also a cowl will have to be built from fiberglass at some point along with wheel pants.
I will post more info later, time for dinner haha.

Jwhitacre1 12-29-2021 08:19 PM

Ok so to catch up here's a cliffs notes of the build til now;
Wing is fairly stock minus wingtips getting it to 51" span and 1" wider ailerons.

Fuselage sides are stock, bulkheads and turtle deck are not. Open cockpit has been added also.

Horizontal and vertical stabs custom to resemble a Gee Bee QED

Motor will be a 35-42-1200 running 2 3 cell 2200 packs

Flying and landing wires plus stabilizer braces will be added

Landing gear from a Great Planes T Craft 20 will be used with most likely wheel pants.

I added 50 more squares of wing area and finished weight is going to be roughly 50oz which will give me a decent loading of 15oz/sq ftCowl and pants will be laid up soon as weather permits which could be a couple months. I'll put up a picture or 2 tomorrow of the progress so far.
That catches up to current status of the build!

michaelgantt 12-30-2021 04:45 AM

looking forward to the pics. I love my four star 54, and i love the planes from the era you are modeling after

Jwhitacre1 12-30-2021 01:17 PM

Picture as promised. The wings are first up as they will be the fastest to finish framing. Hard points for the bracing wires need made up and glued in. Servos are temporarily mounted but will come out for covering. Aileron hinging will be last before covering and I'm planning on using braided fishing line for that.

Jwhitacre1 01-01-2022 03:11 PM

Happy New Year everyone! I'm hoping to get some time on the wing tomorrow, get those bracing mounts put in place. With the minimal things needed on the wing I hope to have it done fairly quick.

Jwhitacre1 01-08-2022 08:05 AM

Bracing mounts
Today I wanted to get the wing mounting point blocks in place. These are where the brass plates I'll make later will secure to. I picked a rib about 2/3 down the span and using nyrods as a mockup I decided that would look the best. Since these are purely aesthetics I have lots of "looks about right" wiggle room. The rear mounts are 3/8 hard balsa aileron hinge blocks leftover from a 90 size build years back(pays to be a parts hoarder). Front blocks are bass wood landing wire blocks from I believe the smaller GP Slow Poke. All 4 are now cut to size and epoxied in. I have running around to do so maybe in the afternoon I can get the fuselage tubes installed

Jwhitacre1 01-08-2022 04:33 PM

I had some spare time after errands so the fuselage flying wire pass through rods went in. The holes were made with the brass rod I'm using with an end sharpened. A drill was used to make a clean hole. The wires will pass though the fuselage and have clevises on either end to the wing mounts. This will cut down on hardware used and less weight over attaching to fuselage and wings. Next up I'll move to the tail bracing mounts.https://cimg3.ibsrv.net/gimg/www.rcu...db692506ce.jpg

Jwhitacre1 01-09-2022 10:05 AM

With the wing ready for sanding I moved to the fuselage. I got a good amount of small stuff out of the way this morning. I put a balsa cap on top of turtle deck behind the cockpit to the vertical stab, installed pushrod guides, epoxied in tail wheel mounting plywood, put an additional rail in the cockpit on each side that I wanted to add, and put in the framework for the bottom fuse behind the wing. I decided to make the fuse bottom semi-round after a lot of thinking it over. It added more work to do making the formers but will look world's better than flat. Once the formers dry I'll sheet the bottom with 1/16 balsa. Next time I work on this the under wing and battery hatch formers will be added to make the whole underside match.I didn't add mounting points today for the tail bracing but will be using cut dowel rod sections for that. I believe it was a Sig Cub that used that method and it worked great.

Jwhitacre1 01-09-2022 01:50 PM

Sheeting on half the bottom is on, I'm really liking how this is turning out. Really glad I decided to go this route.https://cimg0.ibsrv.net/gimg/www.rcu...26419ec8c5.jpg

Jwhitacre1 01-09-2022 04:42 PM

The other bottom sheeting half is on so I'll let that sit for the night and start on the under wing section tomorrow. I can tell once it's all sanded and I few spots of wood filler this will look fantastic.

flyingagin 01-09-2022 04:57 PM

I had a mostly undamaged wing from what I believe was a .40 sized Ugly Stick i stored and packed around thru various moves.

I decided to make a Super Sportster from it. Made it a bolt on wing. Picked up a canopy off eBay.

Right now the plane is about 90% to the covering stage.

But it along with all my other planes is just being stored along with tools and most of our house hold goods.

Moving from California to Missouri. Just Waiting for the property in Missouri to close. should be soon.

Lots of planes to resume and even more projects to to start that are not plane related.



Jwhitacre1 01-09-2022 06:05 PM

Your Sportster looks fantastic! The use of a spare wing is what it's all about, love it. Hopefully your move goes smooth and Swift. Once you get settled in and finish that build I'd love to see the finished product:cool:

flyingagin 01-09-2022 07:29 PM

Thanks Jwhitacre1. I appreciate that. I started it on the spur of the moment when I had pause another plane for lack of material for a month.

I fetched the wing out of the the field garbage can after some else crashed their plane. I have several more wings awaiting a second life (same story) including a pair of bi plane wings sized for a 2 stroke 90 or 120 four stroke. Those will get a 20 to 25cc gas engine. I have a 90 2 stroke but fuel cost and availability were we are moving to is deciding me to go with gas for my bigger planes.

I did a build thread here if you want to se more of it. I'm thinking at some point I'd like to build a 35cc sized Super Sportster. I kind of took a real liking to the Super Sportster.


Jwhitacre1 01-10-2022 06:08 AM

Thanks for the link, I read through the build last night. Very nice build indeed it'll be a sweetheart in the air for sure. A 105" version would be absolutely amazing I wish I was in a position to even consider a build of that size. My current flying field is electric only so this particular build is about big as it gets for me going forward. Gas is the way to go over glow these days and not much heavier compared to the old weed eater conversions (I still have one out in the shed haha) Should life ever lend me the opportunity to use wet fuel in aircraft again it would be gas without a doubt.

flyingagin 01-10-2022 09:18 AM

Thanks Jwhitacre1

I started the Super Sportster Build when I had to pause the Pacific Ace 74" I was building for lack of materials. I already had the lumber and obviously the wing to start the S.S.

And then it was a case of switch back and forth between the two builds. I pushed the P.A. to the front of finish first. And then since we were selling our house and leaving the state to move + 2000 miles, wife and I decided we wanted a camper shell for our pick up. New ones were way to much money, Even more so since our truck is a Super Duty F250. So I built one. As soon as it was finished I mounted it and packed the house and shop. So I have been frozen at that point now. I do have build threads for both the P.A. and the camper shell on the other site.

The P.A
The camper shell

I think you are about right on the size (105") for a big S.S. One change I would make is to make the fuse taller to improve knife edge.


Jwhitacre1 01-10-2022 12:19 PM

I'll have to look both those threads over later today, thanks for the links! 105" popped in my head because years back I planned to get a Sig 1/3 scale Spacewalker and modify it to look more sporty. It never materialized but the concept must be ingrained in the mind. It's probably good I'm limited to electric flight now, keeps me in check:rolleyes:

flyingagin 01-10-2022 02:58 PM

My building is obviously in check at the moment. But I have still been acquiring items for the planned 1/3 scale Pitts. Andy Sheber plans built Pitts s1s.

Bought 90% of the electronics. Purchased the fiberglass cowl, and wheel pants plus the canopy. Those were just beyond my ability. But if I had set my mind to it and had sectional drawings I think I could have figured it out. But likely would have spent even more than it cost me to buy them.

Also bought the engine, a 60cc DLE twin. and the plans, Waiting till after we are moved before buying the wood, fabric, and dope.

Most planes from here on out will be old school for covering. I enjoy covering the old school way, where as I find with the films it is just another job.

I find that anymore I enjoy the journey of the build as much as any thing else. What is great, is that my wife wife supports and encourages me build, and fly. She anxious for me to start the Pitts.

By the way the plane in my Avatar is fabric covered and then painted.

Looking forward to see your build go. What are you useing power wise?


Jwhitacre1 01-10-2022 06:41 PM

That is one big Pitts! That's one aircraft I've always admired but know I couldn't own because I'd put it in doing something outrageous:) Having the wife's blessing is absolutely pivotal way I see it, otherwise it's a never ending debate.
The motor will be a 15 size equivalent out runner swinging an 11X7 prop. Motor calc looked good when I ran quick numbers so it's a keeper. I started on the under wing fuselage hump tonight. A few formers were cut and 1/16x 1/8 balsa rails were glued on. Before the weekend I'll try and get it ready to sheet.

Jwhitacre1 01-10-2022 06:56 PM

I almost forgot, didn't give a picture of the bottom so far.

flyingagin 01-10-2022 08:03 PM

Looking good. Looks like you have a lot of the frame up and basic build done.

The Pitts will be 69.5" top wing span and hoping for 18 or 19 lbs. I will save the outrageous for the Real Flight simulator. I've been flying the Pitts almost exclusively in it. It is actual a fairly easy to handle bird. I have assured my wife no crazy stuff on the Pitts. Crazy stuff will be done on other planes. I have in the past reserved crazy stuff for small and old beater planes. If I get to stupid not that big a deal.


Jwhitacre1 01-11-2022 09:55 PM

I got the other 2 formers in place under the wing and I have to say I really like how it's coming together:) Tomorrow I need to box in around the wing hold down screw and possibly sheet it. I need to dig through my old rocket stuff and see if I have an old A size motor mount to go around the wing screw. That would be perfect size to close that off but be accessible.
The battery hatch will be coming up very soon and I'm already working out a few minor kinks. It will have to extend over the landing gear which actually works well as I can utilize the metal to secure the hatch with magnets in back. The front I haven't worked out yet but I'm sure the securing method will come to me. Enough for today off to bed, I'll try to remember to take pictures tomorrow of the progress.

Jwhitacre1 01-12-2022 03:18 PM

I got too brave once on a larger model, learned from that:rolleyes: Was a 1.20 size Ultimate style Bipe with I believe a 23cc weedie in front. Wanted to see how low I could pull out of flat spins. 2nd time around I found out exactly how high, and that concluded the models life. Hindsight is a wonderful thing haha:)

Jwhitacre1 01-12-2022 03:25 PM

I'm looking at this wing portion that needs sheeted and being it's a compound curve adds time to it. I'll probably cut the halves to shape later and soak then tape onto the formers and let dry overnight. Gluing tomorrow once it's for the most part in the proper shape seems a safe bet. With balsa prices I don't want to waste sheets due to impatient building.

flyingagin 01-12-2022 05:05 PM

You can add some ammonia to water when you soak wood for bending. It helps.
I also have take to steaming wood to bend it. But unless it is narrow strips you would need to make a steam box. For narrow strips I have just used a steam kettle and bent the strip in short lengths by hand. I have done that for laminating strips for built up tail surfaces. On that note I have started to laminate from strips my spars and leading edges for wings. Buying straight stock is near impossible,


Jwhitacre1 01-12-2022 06:15 PM

Ammonia and water...never tried that before. Thanks for the tip I used it tonight on the first half of the sheeting and it's fantastic! Much appreciated:)
Well picture speaks for itself, first half is drying for the night. Tomorrow I'll trim and work on other half. The square stock protruding is my former guide for the battery hatch so the curve is uniform.

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