Sling Pilots Forum

I dimpled mine but not quite to the riveting section yet... maybe the dimple is means to allow for the rivet to be recessed a bit more than normal?

You mean put a domed rivet into a dimpled hole? That sounds strange. I just dimpled the flaps last night and, since the holes were punched for the 3.2mm rivets already, I had to upside them to 4.0mm. I hope to rivet them today. I opted NOT to dimple the ailerons because I haven’t seen that clearance is a problem for them, and the dimpling is just for clearance on the flaps, not for airflow.

My flaps and ailerons are not dimpled/countersunk rivets - just regular domed 3.2 - and I have no clearance issues on either flap or aileron… just a point for future reference (wing kit from Mar 2020)

Thanks!

On a related note to the aileron/flap flush rivet question... When test fitting the flaps I found that it was still rubbing on the bottom of the rivets in the trailing edge of the skin supports even though I did shorten them per the instructions. I decided to replace those pulled rivets with solid ones since the formed head on the bottom was about half as tall (and they were easily accessible with a rivet squeezer). This eliminated any issues with the flaps rubbing.

I did dimple (and use 4mm flush rivets) on the indicated holes for both the flaps and ailerons.

Building the front seats:

The drawing calls out using Ø3.2mmx8mm all around (except for the base brackets), but for the locking mechanism, you need to use 12mm long rivets in the front. The 8mm long ones don't quite go far enough past the plastic so it won't hold correctly. Sling includes (at least in my kit, received late 2021) the 12mm rivets so they know the rivets are needed, but it hasn't made it to sheet 137 of the instructions yet (DC-KAI-003-X-F-7.5 - Sling 4 TSi Fuselage KAI).

PatrickC wrote: ↑Mon Jan 17, 2022 11:04 am On a related note to the aileron/flap flush rivet question... When test fitting the flaps I found that it was still rubbing on the bottom of the rivets in the trailing edge of the skin supports even though I did shorten them per the instructions. I decided to replace those pulled rivets with solid ones since the formed head on the bottom was about half as tall (and they were easily accessible with a rivet squeezer). This eliminated any issues with the flaps rubbing.

I did dimple (and use 4mm flush rivets) on the indicated holes for both the flaps and ailerons.

I did write the factory about this very thing and suggested that they use solid squeezed rivets on the trailing edge when doing quickbuild wings at the factory.

The throttle quadrant section in the fuselage manual shows the lever that attaches to the throttle cable backwards - the bushing and bolt head should be on the outside, nut on the inside (pictured correctly in the Finishing kit manual).

There's also no description on how the throttle cable actually attaches to the bolt. Per Sling Technical (thanks Damien!!):

"The cable will be Crimped between the head of the bolt and the special spacer.

This will happen simultaneously as you tighten the locknut,



A bit of guidance her, hold the head of the bolt stationary and drive the lock nut, to prevent excessive kinking or bending of the throttle cable."

Wings

Noted a number of issues on sheet 15 of the KAI version 6.4: no rivets are indicated for rib 10 to secure it to the main spar; no rivets are indicated in the KAI to secure the front sides of ribs 6-13 to the vertical channels pre-installed on the main spar (critical omission - it's easy to not realise this needs to be done, I only realised it when looking closely at the structure and wondering why the channels were mounted with holes corresponding to the ribs but there were no instructions to rivet them); after contacting the factory, I went with part number 995 rivets for rib 10 and the sides of ribs 6-13.

Also, for the main lower wing skin, in the row of 4mm rivets which attach the skin to the main spar, the last hole closest to the root is overlapped by the lower root skin. That hole must NOT be dimpled even though it is 4mm like the others - the spar hole is larger and not countersunk. This is extremely difficult to see on the KAI skin diagram and is not called out like some of the other holes which should not be dimpled.

The rib 11 reinforcement channel appears to have been modified at some point and the rivet tail no longer interferes with it when attaching the inspection hatch grip plate (KAI ver 6.4) and no longer needs to be shortened. However, the forward-most rivets for rib 11 to attach the skins to the ribs do have interference with the rib 11 brackets and need to be shortened by about 50%.

Vertical Stabilizer

I sent an email off to Sling Technical about upsizing the holes in the rear spar for the bottom two rivnuts on the doubler interfering with the fitment. They responded that I was in no way to upsize the holes, except enough for the bolts to fit through, and that the rivnut touching the spar was not a problem. In the same email they told me I would need a new rear spar because I already made the holes bigger.

I guess I will just need to keep an eye on the section and see if it becomes a problem over time.