Known building "Gotchas" for the Sling TSi

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PhilipRueker
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Known building "Gotchas" for the Sling TSi

Post by PhilipRueker »

There are some questions that keep coming up from new builders and I regularly get asked as one of the earlier builders.

If you're looking for recommendations about tools, we have a thread about many things tools.

I'm going to start this thread as a collection of some of the known things that often come up during the build, or things that are not directly called out in the plans, but the builder should consider.

If you have something to add, please reply and I will try to add it to the summary up here with a link to your reference.

General
  • Dimple Dies
    For some parts of the dimpling of the ribs, the die that sits on the inside edge of the rib may be too large and could cause the skin to be damaged. To prevent this, you may have to grind away a little bit from the side so that it can sit flush. - PhilipRueker
  • Extra Rivets
    The packages of rivets is usually on point, but in some cases will be be missing the total amount needed, probably due to the ever changing manual. Reach out to your dealer to get extra rivets. - MTJ
  • Rivet numbering on build instructions
    Make sure you double check which rivets to use! The Empennage kit uses some terms interchangeably- eg: 997/998/999:
    997 - RIV 142 (3.2mm) on HS, RD
    998 - RIV 153 (4mm) on HS, RD
    But :
    997 - RIV 454 (4mm) on EL and RIV 242 on VS!
    998 - RIV 164 (4.8mm) on EL and RIV 143 on VS! - huzilulu
  • Assembling inspection panels
    The current version of the instructions are not super clear on how to assemble the instruction manual. Here's an attempt to describe the steps. - permagray
Empennage
  • Safety the Elevator Trim Tab
    The plans don't mention it, but you should safety the Elevator Trim tab - this can easily be done by drilling a small hole into each end and installing some Safety wire. - PhilipRueker
  • Horizontal Stabilizer Reinforcement Plate
    seems to be removed from newer iterations of the instructions - If you read some of the earlier build blogs like mine or Matthew Harris', you'll find that we had a triangle reinforcement plate in the Horizontal Stabilizer, but after a recent chat with another builder, it appears that the factory has removed this from their plans. - PhilipRueker
  • Vertical stabilizer bottom bracket on the rear spar calls for 8x 4mm rivets to attach the turning brackets to the rear spar, but actually only the inner 4 holes should be riveted, while the (larger) 4 outer holes should be left as-is for the bolts to attach the Vertical stabilizer to the Fuselage. - PhilipRueker
  • On the rudder tip, the directions on page E.4.4. state that you should countersink the first 9 (nine) holes on the composite rudder tip piece. To match the 7 (seven) rudder tip skin holes that are dimpled, you should only countersink the corresponding 7 (seven) holes in the composite rudder tip piece. - permagray
  • The holes for the Rivnuts on the Vertical Stabilizer are pre-drilled for M3 size and need to be reamed up to fit M4 rivnuts. - MTJ
  • Elevator Counter Weights
    From TAF: This information is missing in our build manual and it will be available in the new TSI empennage manual that we will release this year.
    We normally leave the last 3 rivets on either side of the balance weight arm unriveted. We then install the bolts and the rivets afterwards.
    This provides enough free space to fit the balance weights properly.
    The bolts are short but you should not install them with washers. This will give you about 1.5 threads sticking out from the lock nut.
    The bolts & nuts must also be torqued to the correct value as specified in the introduction document. - MTJ
  • Vertical Stabilizer - Page E 3.3 - Dated 2018/11/14. Extra context
    Some builders will receive part 14 with 6 holes punched to M3 size and 5 holes to 3.2 mm. As shown in the diagram there should be 7 rivnuts installed which means drilling/reaming all 6 M3 holes and one of the 3.2mm holes to M4 size for the larger rivnuts. The same is true for the two M3 sized holes on part 9.
    Also, some builders will receive parts 11 and 12 where the side holes do not align well enough with the channel holes. The build center says it is OK to drill out the holes to rivet if necessary. - permagray
  • Vertical Stabilizer rivnuts Extra context
    On the rear spar of the Vertical Stabilizer, there are a series of 7 Rivnuts that get attached to the doubler plate, as well as two attached to the Angle bracket.
    there is spacing between the double and the angle bracket for the 7 rivnuts for uniform load, but I had to enlarge the holes in the main rear spar for the bottom two rivnuts to sit flush or else they would push out the rear spar and may creates stress leading to metal fatigue. You can see in the Finishing Kit instructions that those bottom 2 rivnut heads are visible that support my reading of the situation. - PhilipRueker
  • On page E 2.4 of the Empennage 2018/11/15 build manual - Step 6 - it says to use 4.8 x 12mm rivets. Such rivets are not supplied from the factory. The build center in Torrance says to use 4.8 x 15mm instead (RIV-165). - permagray
  • On page E 2.5 of the Empennage 2018/11/15 build manual - Step 11 - The Gusset Channel angled attach point to the outside Elevator Rib 4 uses 3.2 x 8 rivets. NOTE: The instructions omit that you need to attach the Elevator Spar Extension Channel (EL-CHL-006-X-A-1) BEFORE you rivet Elevator Rib 4 to the main channel. There is no mention of attaching the extension channels other than a visual of it attached in Step 16 on page E 2.6. - permagray
Wings
  • Pitot Tube inspection Panel
    Installing the Pitot Tube may require you to cut an extra inspection hole into the Wing, particularly if you are building from a Quickbuild with the Wings already built, as you will have no way to install the Pitot tube otherwise.
    After chatting with the Factory a while back, they drew up the plans for the cut and sent me the plate, which is the same as the other inspection covers. - PhilipRueker
  • AN Bolts for the Aileron & Flaps are in the Finishing Kit - PhilipRueker
  • Use 3.2x6mm rivets on the trailing edge skin of the wing along where the flaps mate. The 3.2x8mm rivets that it says to use will be too long and contact the flap when fully retracted. Even the shorter rivets will need to be filed down a bit (factory recommendation) - ebrunye
  • Autopilot pushrods are part of the ELECTRICS kit, which I was told is better not to order, just source wires yourself. But you will need the pushrods! - ebrunye
  • Wing manual rev. 5 states to dimple/countersink the Flap skin - not needed (note is an error)
    Ailerons - rivet #997 should be 2.4 x 6mm stainless steel rivets, not 3.2mm - huzilulu
  • Rear Spar - Rear spar rivets should definitely be done from the outside of the spar, not the inside, or they will clash with the aileron (rivet direction is not clear from the manual). - sashaa
  • Wing Rib Assembly - The 4.8 mm rivets shown on the Wing Rib 14 Assembly should definitely not be pulled when the manual says to, as otherwise there is no way to attach the rib to the wing.- sashaa
  • Wing assembly - Manual never specifies it, but once you install the bolts and angle bracket for the fuel tank mount they should get a thin washer and nut pretty much immediately to match with the rest of the bolts/nuts on the main spar.- sashaa
  • Wing assembly - Not sure how its possible to rivet the skin under Wing Rib 11 Assembly – that bracket they put on there is super in-the-way. We’re going to try doing it with 3.2 x 6 mm rivets and will report back.- sashaa
  • Wing assembly - Nylon edge protector should be applied around the edge of each rib that contacts the stringer, as there is the chance that cables in the stringer vibrate along the rib edge (they have this in Mojogrip’s build assist videos, but its not specified in the manual). - sashaa
  • Fuel tank - Applying Loctite 577 thread sealant on the threads of all fuel tank fittings will screw you over once calibration time comes around, as Loctite 577 makes it impossible to remove the threads. Use EZ lubricant instead! - sashaa
  • Fuel tank - The default Fuel Lever Sender plate that comes with the Fuel Level Sender should be removed and stored somewhere completely different – you will basically not have use for it again as it is replaced with the custom Sling TSi Fuel Level Sender Plate. - sashaa
  • Fuel tank – WG-CLM-002-X-F-0 came unbent for us (literally just a straight piece of aluminum) and we had to bend it to the correct clamp shape (no mention of this in the manual).- sashaa
  • Fuel tank – a bunch of the holes in the skin and the ribs were under-sized for us. You have to carefully Dremel them up or drill them up the right size (for the case of the fuel tank skin where it mounts to the wing).- sashaa
Fuselage
  • Rudder pedal pushrod bolts are in the Finishing Kit - ebrunye
  • The shorter ribs at the floor of the rear fuselage are switched in the manual, they should face opening inwards not outwards - ebrunye
  • Aileron stops are shown backwards - ebrunye
  • ADSB blade antenna goes in the small hole in the front/center fuselage skins. Be aware of this when you apply soundproofing - ebrunye
  • Rear Top skin of the Fuselage holes have a known misalignment issue - full details on the workaround form Evan here. - ebrunye
  • Parking Brake valve
    The 1/8 NPT 90 degree fitting will not fit into the valve because it is 1/8 BSP. Here is what TAF says
    The thread on the fittings is 1/8” NPT and inside the valve is 1/8” BSP – the 2 threads are almost the same but don’t quite fit. What we do is get a 1/8” BSP die nut and clean the thread of the fittings. Apologies – it should be in the manual. - MTJ
Gears
  • Building up the Nose Gear and the TAF manual has the tow bar linkage orientated opposite in the diagrams (P1.3) Refer to the later mounting pages for the correct directions. - MTJ
  • Nose Gear & Powder Coat
    I have noticed many builders removing the powder coating on the strut for smooth turning. I asked TAF Technical exactly where and what range of powder coating to remove. Here is the reply...
    The nose gear is E-coated. The dimension of the part remain the same once it has gone through this process.
    The tube is a tight fit due to the Bushes (Item 11 in your image). It is better to sand out the inner diameter of the bush. Each one is different and so I cannot give you an exact dimension. You will have to remove a little bit at a time.
    Grind the bushing but don't remove the powder coating seems to be the answer.- MTJ
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PhilipRueker
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Re: Known building "Gotchas"

Post by PhilipRueker »

-- reserved in case the list above ever grows beyond one post --
ebrunye
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Re: Known building "Gotchas"

Post by ebrunye »

-Rudder pedal pushrod bolts are in the finishing kit
-The shorter ribs at the floor of the rear fuselage are switched in the manual, they should face opening inwards not outwards
-Aileron stops are shown backwards
-ADSB blade antenna goes in the small hole in the front/center fuselage skins. Be aware of this when you apply soundproofing
-Use 3.2x6mm rivets on the trailing edge skin of the wing along where the flaps mate. The 3.2x8mm rivets that it says to use will be too long and
contact the flap when fully retracted. Even the shorter rivets will need to be filed down a bit (factory recommendation)
-Autopilot pushrods are part of the ELECTRICS kit, which I was told is better not to order, just source wires yourself. But you will need the pushrods!

I think these are all only for the standard kit and won't apply to the quickbuild. That's all I remember off the top of my head I'll add more if I remember.
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Re: Known building "Gotchas"

Post by PhilipRueker »

Great additions, which reminded me of another one:
  • The AN bolts for Ailerons & Flaps are in the Finishing kit
I've added all the tips to the top post and organized them by main structure (Empennage, Wings, etc.) and added a suffix for who added the tip in case future builders need further clarification of who added the recommendation.
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Re: Known building "Gotchas" for the Sling TSi

Post by PhilipRueker »

One more Gotcha about the dimple dies when dimpling some of the ribs:

Dimple Dies
For some parts of the dimpling of the ribs, the die that sits on the inside edge of the rib may be too large and could cause the skin to be damaged. To prevent this, you may have to grind away a little bit from the side so that it can sit flush.
Building a Sling TSi in my Garage.
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Re: Known building "Gotchas" for the Sling TSi

Post by PhilipRueker »

Vertical stabilizer bottom bracket on the rear spar calls for 8x 4mm rivets to attach the turning brackets to the rear spar, but actually only the inner 4 holes should be riveted, while the (larger) 4 outer holes should be left as-is for the bolts to attach the Vertical stabilizer to the Fuselage.
Image
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ebrunye
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Re: Known building "Gotchas" for the Sling TSi

Post by ebrunye »

I've got a new "Gotcha"

The Rear Top Skins of the fuselage holes do not align properly where they meet up with the bottom skins. The forward 2/3 of holes align properly, and the back 1/3 do not. Also, almost none of the holes on either skin align on the farthest aft rib (smallest one) The factory is aware of the issue and working on redesign, but as of now they say all kits still have this issue.

Here's how I solved it (per factory recommendation)
Start with the left skin where it meets the bottom skin (along mid line of fuselage side.) Keep in mind the clecos will only align on the front 2/3 of the skins. Work the skin up along the ribs, clecoing in place. Do the same on the right. This should allow the skins to meet up properly at the top, because if you try to meet them at the top first the ribs allow too much flex/twist and you will have a hell of a time aligning the sides. Don't ask how I know.

Rivet everything in place that aligns properly, and then starting with the forward most hole drill them out one at a time, front to back, clecoing along the way. On the rear rib, start at the top middle hole (which aligns fine) and work your way down each side, I did one on the left then one on the right, until they were done the whole way down. These need to be drilled a little more, the factory said up to 4.8mm is acceptable.
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Re: Known building "Gotchas" for the Sling TSi

Post by permagray »

On the rudder tip, the directions on page E.4.4. state that you should countersink the first 9 (nine) holes on the composite rudder tip piece.

To match the 7 (seven) rudder tip skin holes that are dimpled, you should only countersink the corresponding 7 (seven) holes in the composite rudder tip piece.
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Re: Known building "Gotchas" for the Sling TSi

Post by MTJ »

I am on step 5 of the Vertical Stab build. The outer holes for mounting screws is a huge gotcha!

ALL my M4 predrilled holes are predrilled M3. Gotta start reaming.

Thanks for all that post
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Re: Known building "Gotchas" for the Sling TSi

Post by MTJ »

Many pilots have been shorted rivets... I guess I'll join that group ("me,too? ;) )

Barry and Perry asked me guesstimate (WAG) what I need. I am somewhere in the neighbor hood of 25% short 142 & 242 rivets. Not as many 153 rivets missing. I think I'll get those soon

South Africa is on a more draconian lock down so the earliest missing part shipment is later in May.

Plan accordingly
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