Airmaster Prop - Service Bulletin #22

I tripped across a Service Bulletin from Airmaster (SB #22).  

The issue:  In 'high vibration' environments / engines, the brush assembly in the motor can crack.  This SB affects version 1 and 2 of the pitch change motors.  I have version 2A.

Discussing with the US distributor, he had not heard of this SB.  He also mentioned that because the UL engines are so smooth this should not be an issue.  However, might as well do it... the irony is I had just torqued the hub onto the flange the day I discovered this.  No big deal, except I will need some new nordlock washers.

The procedure is very detailed on how to extract the motor.  I opted to take everything apart (the procedure says it can be done in place).

Only 1 issue:  In step 4, you remove the 'riv-screws' on the motor clamp with a 2.5mm hex key.  The first one came out no problem.  #2 just spun.  #3 came out fine... and the rest just spun as well.

I called Airmaster... they have never seen this before.  "Do whatever you need to do to remove the rivscrews, and we will replace whatever parts are damaged.".  We agreed that an easy out would do the job... it was 7PM at night when I discovered this (in a cold dark hangar), so figured I would do this the next day.  As I was packing up, I had the brainwave that a thin slotted screw driver tapped into the head with a hammer may do the job... and it did.

Back in business!  Everything packed and ready to ship.  Airmaster says the upgrade will take about a week once they receive it.

They received it on Fri, Jan 17 2025.  Return ship on Thu, Jan 23 (NZ time).  Should have it on Wed, Jan 29.

Per Airmaster tech support, they have replaced my motor with a new Maxon carbon brush motor as it 'is more suited for my engine'.  Both Tracy and Ray have been running with the Faulhaber motor for YEARS... so I asked why?  The new motor is a carbon brush motor, and is 'worth more' than the previous.  Cut and paste from the email...

The maxon motor you are receiving is also a carbon-brushed motor, however we have modified the original design so that it is more resilient to vibration, this is due to the implementation of thicker brush braids, higher-pressure springs, and an overall more resilient design that puts less strain on the brushes leads.

The UL520T engine may be considered smooth but it is still a direct drive engine so there is less of a damping effect on the prop.

Will see... looking forward to it.

On a related note, in talking to Ray, Airmaster is working on a new controller that will interface with the ECU and provide true 'one lever' operation.  This will allow constant speed props to be used with LSA (in the US).  Sounds very cool...

Motor received back from New Zealand!  Reassembly fairly straight forward, except that the motor wires on the new assembly are in a different location, and require different routing.

The above pic was simply to check I had it right... sent to Jack @ Airmaster for confirmation.  Now I can route everything neatly and finish reassembly.

Prop is all back on and done and tested.  Glad this one is behind me.

Seat Belt Service Bulletin 69

Service Bulletin 69

I opted for the 'weld up' option, and everything is open and exposed, and its lighter.  Plus I wanted to do the gear truss (welded) upgrade, so might as well go all in.

The short version of this SB.... in the forward seat position, the angle of the belts is not ideal.  This doesn't really apply to me (with the seat all the way back), but figured I might as well do it.

There are 4 components to the upgrade:

1. Center post that is welded into the centre truss.  Provides the inboard lap belt tie in.

2. Outboard mount points (x2)

3. New (longer) seat belts.

The first part of the upgrade is pretty simple, as it almost centers itself in the centre truss.

The outboard mount points are a bit trickier, as they are in 2 parts.  One is a plate with a sleeve, and then a 2nd plate gets welded on after.

As per usual, once everything is located you need to gently remove the paint, and prep everything for welding.

Once everything is prepped, I used weld through primer on all the surfaces that you won't be able to get to after the fact.

And all finished....

Tailwheel and Service Bulletins

 Service Bulletin 70 - complete.

Trident shaped reinforcement fully installed.  All bolts torqued and marked.  Rudder stops reinstalled, but I still need to adjust the stop plate to get full rudder travel.

Forward tailwheel mount:

Upper and lower mounts test fit:

Drilling the hole was a challenge.  The sheer web mounts are already in place, so I had to get creative on how to drill the hole between the forward upper and lower mounts.

Two right angle drill adapters coupled together.  It worked out in the end...

Bonding the forward mounts in place...

1/4" bolt holding them in place now while the resin/cabosil dries.  Then will enlarge to 3/8".

The resin started eating away the Zinc Chromate primer.... the acetone to clean up the mess made more of a mess.  Will have to try and prime in place, however the epoxy will protect - plus all the brackets have been alodyned - so this is really cosmetic at this point.  Not a structural issues.

Next:

- Drilling the forward mount to size.

- Aligning the T3

- Drilling the rear mounts

Tailwheel has been shipped, and should be here by end of week.  Tail pull handle is on the way as well, so it can drilled and installed.  Forward gear truss upgrade started.  The 1" OD 4130 tubing has been split in half and is ready to be fit.

Panel, glare shield, floorboards, camera windows, upper cable cover etc ordered from Glasair.  3 to 4 weeks out (no rush).

Next order is hubs, brakes and bush wheels.  Hopefully later this week.

Progress is being made...

Fuselage.... progress

 Have continued to work on ordering parts.  Next orders will be:

1. Alaska Bushwheel mains, rims and brakes.
2. Glasair:  Floor boards (front and rear), instrument panel, glare shield, seats, upper tunnel cover. 
3. Stainless brake lines and fittings (already done)
4. Firewall aft UL Power components (pumps, etc) (already done)

Ordering parts - while it sounds easy - is not.  Many businesses will not ship to Canada, or accept credit cards / PayPal.  Many cheques have been sent... plus, the Glasair manual lists of their part numbers, and sometimes some sleuthing is involved in finding the actual part number.

However, at this point I have everything on order for the gear, fuselage upgrades, and interior.  The credit card is warm.

Getting to building... fuselage has been leveled in the garage.

Service Bulletin 70 (Vertical Fin Cracks)

GlaStar/Sportsman Service Bulletin 70REFERENCE: Vertical fin cracks

As the aircraft has never flown, there is no signs of damage on the fin or bulkheads.  However, I am going to reinforce them while I am at it.

Vertical fin spar reinforcement

All of the sheerweb angles and lower rudder hinge were removed, and the doubler drilled from the aft side.  Then crawled up the fuselage (wasn't as bad as I thought.... but I took my phone with my in case I had to call for help LOL) and drilled the existing mounts from the back.  Everything fit correctly.

However, the existing bolts not long enough now, and need to be ordered.

I am going to do the bulkhead reinforcement, and then rivet this doubler in place.

Tailwheel mount:

The forward mount consists of two aluminum mounts.  The upper ties into bulkhead D, and the bottom is epoxied to the bottom of the fuselage.  The bolt runs all the way through this entire assembly.

My T3 arrived.  It will fit nicely...

And my tailwheel will be ready in about a week...  From the tundratailwheel.com site...

Next step is fiberglass work.  Service Bulletin 74.

GlaStar/Sportsman Service Bulletin 74-Rev AREFERENCE: Fuselage Tail Cone Damage.

I really dont think this will be an option with the T3.  The rear saddle contours to the fuselage, rather than a standard leaf spring mount where the leaf springs are compressed against the fuselage with a mount and bolt on each side.  But I am not going to take the chance, and do the work anyway.

All the 4130 for the gear truss upgrade arrived yesterday, and the tail pull handle should be arriving any day now.