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View Full Version : Doug STI Series 5 to 6.5 or so build



ddawson
12-10-2019, 10:53 PM
I picked up a used Series 5 Kit I will be doing several Series 7 upgrades so by the time I get done it will be Series 6.5 STI or so. Any advice or suggestions will be greatly appreciated.

bbs428
12-11-2019, 02:50 AM
Welcome and congratz finding your 5 Doug.

I like your fuselage work stand! Frame looks great. Looks like it was stored well over the years.
Do you know the year mfg? You said STI so I take it that your going to order those wings? Did your kit include the std. wings? Have you decided what engine you might use? Avionics?

I'm also building a 5 and replaced the elevator, fwf, turtleback, windscreen and doors with new 7 parts. Also added a razorback. Search razorback and you'll get some pic's.

I never built a plane before. Only advice I can give is to work everyday if possible, Do the best you can, keep it light as possible and enjoy the build process. Try not creating unnecessary anxiety with unrealistic finish dates. Search all the builds. There is a HUGE amount of info and pic's that will help you along the way.

My buddy says their are flyers and their are builders - usually not one in the same! lol. :D
But tbh, this is a group of tenacious and very successful builders AND flyers. You will not find a better bunch. They offer a great deal of expertise, humor and encouragement.

All the best.

ddawson
12-12-2019, 09:13 AM
This is my first build as well and Yes I am ordering the STi wing and I do have the standard wings that came with the kit as well as I upgraded the elevator and will be upgrading the doors and windscreen to the light smoke. Im planning on a Rotax 915 for the engine and dual 10" Dynon HDX glass panels for avionics. Im also having the tailwheel mount beefed up. I am researching adding a razorback as well. Thats as far as I've gotten Stay tuned.


Welcome and congratz finding your 5 Doug.

I like your fuselage work stand! Frame looks great. Looks like it was stored well over the years.
Do you know the year mfg? You said STI so I take it that your going to order those wings? Did your kit include the std. wings? Have you decided what engine you might use? Avionics?

I'm also building a 5 and replaced the elevator, fwf, turtleback, windscreen and doors with new 7 parts. Also added a razorback. Search razorback and you'll get some pic's.

I never built a plane before. Only advice I can give is to work everyday if possible, Do the best you can, keep it light as possible and enjoy the build process. Try not creating unnecessary anxiety with unrealistic finish dates. Search all the builds. There is a HUGE amount of info and pic's that will help you along the way.

My buddy says their are flyers and their are builders - usually not one in the same! lol. :D
But tbh, this is a group of tenacious and very successful builders AND flyers. You will not find a better bunch. They offer a great deal of expertise, humor and encouragement.

All the best.

ddawson
01-02-2020, 11:43 PM
Update:
I am going to be having some updates to my airframe next week beefed up tailwheel mount tabs for aluminum header tank and seat as well as extra antenna mount for
the ADS-B In/Weather and a razor back so it will almost be brought up to a series 7 specs. So while I'm waiting been working on fitting ribs for elevator, and horizontal stabilizer.
So I am getting ready for my first go around with the Hysol. been reading some posts and several bits of great advice.

23772

DesertFox4
01-02-2020, 11:55 PM
Very good Doug. The razorback does look great and makes covering nicer at the vertical stabilizer area of the fuselage.
The 915 really hauls the mail on an STi Kitfox. Fun stuff ahead for you.😀

rcbif
01-03-2020, 09:49 AM
Update:
I am going to be having some updates to my airframe next week beefed up tailwheel mount tabs for aluminum header tank and seat as well as extra antenna mount for
the ADS-B In/Weather and a razor back so it will almost be brought up to a series 7 specs.



I'm building a 5 and have the aluminum header tank. Do Adel clamps not work? I haven't tried positioning my tank yet.

I'm contemplating seeing if I can order the weldment pieces Kitfox uses for the 7SS razorback to add to my 5 as well since it doubles as an antenna mount which I will need anyways since I'm using the longer turtledeck.
However, I'm not crazy about the amount of welding that has to be done to the vertical stabilizer tube - dont wanna mess that up.

ddawson
01-04-2020, 09:02 PM
I'm building a 5 and have the aluminum header tank. Do Adel clamps not work? I haven't tried positioning my tank yet.

I'm contemplating seeing if I can order the weldment pieces Kitfox uses for the 7SS razorback to add to my 5 as well since it doubles as an antenna mount which I will need anyways since I'm using the longer turtledeck.
However, I'm not crazy about the amount of welding that has to be done to the vertical stabilizer tube - dont wanna mess that up.


The Adel clamps would probably work fine, the S7 airframe has the tabs welded on so I am going the same way.

DesertFox4
01-04-2020, 09:15 PM
Adell clamps work fine.

jmodguy
01-05-2020, 06:45 AM
Mine is a series 5 and I added the Razorback the old fashioned Kitfox way, i.e. a tube with plywood supports. Kitfox no longer makes them so I rolled my own. Went in easy enough. I used a forstener bit to cut lightening holes in the 1/4” ply support. For the tube, I used aluminum that was same dia as the fwd vertical fin tube. Made a bend jig by cutting a notch in an old 2x8, bent the tube to my liking and hysoled it in. On either end I cut a relief so it fit the mating tubes properly.
The only thing I wish I had done was to add the later elevator push rod and longer baggage area.

As for the aluminum tank, adel clamps are more than sufficient.
I have an aluminum tank that I bought from Kitfox and won’t be using... 🤔

airlina
01-05-2020, 11:20 AM
Did about the same on my Series5 as Jeff's description , on a no weld razorback , before the Kitfox had a razorback. Here are a few photos from my build manual from the olden days. As I recall i used 5/8"o.d. aluminum tube bent in the jig you see here. Used Scotch/weld (the old hysol) at tube to tube junctions. Bruce N199CL

rcbif
01-08-2020, 12:40 PM
Did about the same on my Series5 as Jeff's description , on a no weld razorback , before the Kitfox had a razorback. Here are a few photos from my build manual from the olden days. As I recall i used 5/8"o.d. aluminum tube bent in the jig you see here. Used Scotch/weld (the old hysol) at tube to tube junctions. Bruce N199CL

Looks like an aluminum plate and two adel clamps mid-span?

How is the aluminum plate held to the tube? Just hysol and fabric pressure?

airlina
01-08-2020, 04:44 PM
Sorry about the quality or lack thereof of these pictures , they are pictures of photos in my build manual ., but you are mostly correct, the mid span support is aircraft grade plywood held to the fuse tube with adel clamps and scotch-welded to the razorback aluminum tube. No issues in 16 years . Remember all our ribs are held in place the same way. Bruce N199CL