Engine advice

Found this on the FB page from Regan Clark.

The Franklin is usually a very smooth and sweet sounding engine. Looked after they can give good service life.

Things to watch for: 14 mm threads on spark plugs instead of the usual 20 mm and the meat can let go and blow a spark plug out – thread lube / anti seize compound, proper torque – don’t over torque.

Intake seals will leak and engine will run lean on that side and eventually backfire blowing intake elbow out a quarter inch or more – with full throttle, full rich and carb heat (enrichens) may still get 40 to 50 % power until you pull throttle back for landing at which point – at what ever altitude – the engine will quit completely – make sure seals are in good condition and no deformation of structure, wipe with alcohol and run a bead of clear silicon around the outside so the sucking action works with the sealant.

If still have cast iron valve guides, and aircraft sits for a prolonged period – depending on humidity and other factors – they can rust and seize or restrict the valve stems and can cause a valve to break and drop into cylinder – partial power loss and big pucker factor – as your Engineer/A&P, I “can’t” recommend using a can of STP every second oil change as STP is not an approved product …a cup of Marvel Mystery Oil in the gas, however, is approved and apparently helps avoid this problem. Otherwise, good habit if the engine hasn’t run in a long time, pull the valve covers and slowly, genitally rotate prop by hand and watch for rocker arm action and associated valve response after clearance gap is closed.

Fuel starvation; the Frank tends to be a fuel hog compared to near equivalent Lyc or Cont. if you’re not use to the Frank it can surprise a person – on my 165 Hp, I found that doing circuits it would easily burn 10 gallons per hour and with a fine pitch prop, in cruise it wasn’t much better. I always planned for 10 gallons an hour and I never ran out of gas. Having said, as with all light single engine aircraft, best to keep at least one eye out for an open field.

 

Disassembly of rudder pedals

Today I took the rudder pedals apart in prep for installing them in the fuselage when it returns. 

There is a good article on this at http://www.hangar9aeroworks.com/108Torquetube.html

Planning on blasting the pedals, but not the torque tubes as they are two piece and lubricated so they move to actuate the brakes. Don’t want any blast media in there. I will be painting the tubes once cleaned. the bearings are in decent shape and I will know more after the cleanup, but I may have to take the advice from the site above and replace with a similar bearing. 

Cracked flap hinge butt rib cont

Today I continued to work on the cracked flap hinge butt rib on the Left wing. I removed the “Edge Assy” 108-1111045-0 which then allowed me to get into where the butt rib is. 

Removing this was a PITA. The PK screws were rusted in requiring me to use penetrating oil to loosen them up. Then I had to purchase a LONG 1/8” drill bit bc there are about 5 rivets right beside the hinges which makes it hard to get your drill in there. 

Flap trailing edge assy.

The cracked rib is at Station 46 as measured from the root. 

Measured from the wing root
Station 46

There are about 30+ rivets holding this butt rib. The rib is not only riveted to the Spar, but also to the main rib with doublers. 

Cracked butt rib
Parts catalog
Parts catalog

Control attachements “Felt washer”

Today while working on the cracked butt rib, I noticed something about the hardware that holds the flaps on the hinges. 

Each hinge has a “bearing/bushing” where the bolt goes through the Hinge. This bushing protrudes outside and wider than the hinge it self. There is a Felt Washer  that goes over the bushing.

P/N 108-8001001 Felt Seal (2 required per hanger)\

Showing washer
Washer installed

Example of what this felt washer looks like new, thanks to https://n9391k.wordpress.com

On the move again

Fuselage after media blast in green epoxy primer

On 16Oct we will drive out to Justin Tx to pick up the fuselage from Rick Wright’s hangar. 

We will be taking it to Brent Henneman’s airport in Quinlan Tx (T41). Brent will be helping me with some tube repairs like the one at the right front gear attach cluster and also apply the white paint.

Gear repair
Right front gear attach cluster.

Prop decision, even though its a ways out

MT composite Prop

Today I got an email from Hercules Propeller in the UK. I sent them a pic of the prop I fell in love with which was this composite MT I saw on this red 108-3.  

Below is the email I received from Hercules today and it sounds like they can make this happen for just a little over $2000!


Hi Will, Yes we can.  We can effectively use the same design which performed successfully on Darrell’s 108 although manufacture it with the sweeping plan-form.  It will effectively be the same prop aerodynamically.  No problem to finish the prop in gloss black and square tip to look like the aircraft in the picture you sent.

Rupert Wasey
 
Managing Director
Hercules Propellers Ltd
+44 (0) 1453 885853
 

So they would take this design prop, square tip it, and paint it Gloss Black! Now I just need to come up with a spinner…..

 
 
 
Another option may be Catto Propellers. https://www.cattoprops.com