Back at the engine

I took off the induction system, all accessories and bagged/labelled all the nuts and bolts.  It's ready for the uniloader to take it off the mount so I can reach the last pan bolts and remove the accessory case then drop the "bottom" (really the center core with crank/cam) into the car to transport to Tulsa for the engine shop to do final dissambly, clean, magnaflux, measure and re-assemble the core.  I'll put the pan, accessory case, jugs, accessories, induction back on when it returns in late January.

Not a bad bad-weather project... I'm certainly no missing any flying and I'd just be in my office wondering how rusty my cam was getting.

Engine Overhaul

Back in August at #OSH17, I watched a Lycoming seminar on how to re-assemble the bottom end after an overhaul.  It didn't look easy, but it looked like something I could do.  So...

I'm going to tare down and ship off the engine for overhaul while I rebuild the canopy.

So... I'm going to pull the jugs, tare down the case, bag everything carefully, stuff it in the back of the Chevy Volt and road trip to Tulsa where I'll drop off the crank and cam with Aircraft Specialties, the case and the jugs with Ney.  I'm setting up an arrangement with an old RV-hand to do an bottom-end-assemble-assist when the parts come back with tags.

I've already dis-assembled an accessory case once, it wasn't hard and nothing to screw up.  As it's my frist time, I'd feel much more comfortable being a hands on helper.  Once the bottom end is one, I'll slap on the accessory case, new oil pan and jugs and good as gold.  And I'll spend probably half to a third as much as a typical overhaul.

Canopy First

I'm trying to tackle big projects that don't need a ton of money.  The canopy has been a bane of this aircraft from the first.  It is totally custom and really poorly done.  Let's start with the first... it's just shaped wrong.  I wanted to use more of the canopy than I should have, so it sits too high and forward on the cabin.  To fix this, I'm going to drop it about 2" and move it aft about 12" trimming the aft and some bottom sections.  This will have three drag benefits and one trade-off.

Decreased plate and wetted area (less drag)

Smoother flow around the cowl and the aft fuselage (less drag)

Better front seal so air can't sneak under and in as easily (less drag and weather resistance) 

... at the cost of; Less headroom / tighter feeling

Speaking with folks that know... this will be a significant alteration, it should yield 2+ (even more with other improvements).  

Current status: I've got some of the materials to rebuild and I have a plan.  Stay tuned, I'll be working on this soon.

Total Efficiency

I built N254MM with assistance from friends and family in 2008.  I made decisions while building to make a very efficient and light RV. 

I've helped paint it, done a big panel upgrade to G3X, added a good comm radio.  Then I sold it!

... not the end of the story.

The month after I sold it I reached out to the guy I sold it to and asked if there was an opertunity to buy it back.  He said yes, but I'd have to wait a couple years.  Well, this Spring, he was ready.  I sold the RV-6 I was working on and took possesion of RV-4 N254MM again.


And flew it to Oshkosh 2017!  Life long dream, but I realized, I had a "mediocre" at best RV.  Which kinda bummed me out.  The problem was all "fit and finish".  I've been so busy with life and flying, issues have built up over time and need to be addressed.  I don't want a sub-par RV, just a disgrace.

The last few months I've taken some time to fly it generally and man..  With all it's nagging issues, it is a phenomenal aircraft and flys so amazingly well, it's worth improving.  Along with the time flying, I've taken time to think about what I'd like the plane to become.  And... I want to realize the origonal goal.  A maximally efficient RV. 

The Goals

Currently

30 sm/g - 140KTAS at 9,500' consuming 5gph 

Immediate Goal

40 sm/g  - 150KTAS consuming 4gph

Crazy stretch goal

50 sm/g - 170KTAS (120IAS @ 17,500) consuming 3.7gph



My goal is very ambitious.... 50mph  That's 170ktas (120kias @17,500) consuming 3.7 gph.

The work

Repair

• Repair leaky fuel tank
• Repair wheel pants

Clean up

• Remove redundent fuel gauge and intercom [Done]
• Replace gear leg fairings
• Add elevator root fairings
• Cleanup tailwheel drag

Rebuild/replace

• Rebuild Canopy [In Progress]
• New round-inlet cowl [Ordered] 

Big Ticket Items

• Replace fuel injection system with SDS Engine Management [$3k net]
• Replace cool-air induction system [$500]
• Replace 4-pipe exhaust with 4:1 and cleanup lower cowl convergence zone, pressure recovery [$1000]
• Ovehaul Engine - 2450 TT since factory new [$5000 field-assembled by me]

Other than that... it's all easy right ;)

Stay tuned