Doing something different to the day job ….

Having spent a few days on Teams and QA bits and automation it’s the time to get out and do a full Test Flight Schedule … a 14 page document to be completed for the authorities after any ‘significant’ work … an engine refurbishment is classed as ‘significant’ …

so it’s powered, timed climbs, logging pressures and engine and exhaust temperatures and climb rates …

stalls .. ie basically closing the throttle and waiting for it to slow right down and stop flying ..3 of those …

then dive at full speed … then pull out (ideallly) … and put her sideways with crossed controls then let go of the aileron … do that both ways and log what happens … then setup for landing and put full power and climb away and then down to land

Now try all of that with a biro in your mouth whilst noting the facts and figures and effects … in an open cockpit …

All in a (exciting) days work 😊

Admission … flying takes a chunk of your brainpower as you focus on the various normal tasks …. Now add the slight overload of a flight test .. which raises the stakes a little …ie you have done ‘bits’ that, by their nature, need testing …. Then add the capture of all those measures like oil temp and press … CHT 1 and 2 and EGT 1 and 2 .. and ASI .. and cloud base of the extended climb … and lookout …. And omitted one thing …..

..so, was that Tibenham below … oops no … it’s Old Buckenham …. The drift at 3,500 was appreciably more than I’d planned … they probably wondered who his loon was stalling and diving and turning around !

One of the ‘new’ post flight jobs I’ve got to get used to now in the U.K. … is wiping the muddy bottom post landing 😊 a nice job ..after a lovely curving approach down to Priory grass ..

Loads of strip lights in the barn make it very easy to get the old oil filter off and a new one part filled and tightened up against the TOCA unit.

Then don’t forget to wire lock the drain plug and tie off

Then remove the 8 or so very small polished hex bolts and nylocs from the front screen… the one that I very carefully cleaned with brake cleaner !

The old screen was out in around 15 minutes so a quick clean up of the area and then e move some of the protective covering on the new screen before drilling the pilot holes.

Love using clecos … such a simple and useful tool

Using a narrow metal rule to prevent the drill overrun going through the cockpit coving … like it did 6 years ago ! Rookie error 😊

Having had the much improved refurb of the engine it looks like we have too much oil getting into the rocker boxes … it’s good to have them lubed …but not over lubed

The pipes from the sump route oil up to the rocker boxes and it then drains back down the alloy pushrod tubes …

If the feed is too great then 5e exit back down into the sump can’t keep up … so the rockers fill and, eventually, it reaches the old vent drilled hole that allows venting to the head fins

To confirm all this I’ve now got use of a converted rocker box head … that has had the centre cut out and a glass inspection panel sealed in place. This will allow us to run up to speed and eyeball exactly what is happening

If we find the oil supply is too great … then it’s probably a simple switchover of the oil feed pipes … it seems the ones in place now are high capacity feed

Update .. late September … looks like it might have been user error. I replaced the oil cooler matrix with a new slightly larger one … and, on refilling with oil, I was over generous allowing for the new EMPTY matrix … by about 750ml ! This had nowhere to go .. except out through the breathers …lesson learned 😊

Been offline way too long and really look forward to some cool ‘wrap up’ type flights

As well as the flight in the Sherwood demo aircraft recently .. I managed to get a session in a Cessna 152 Aerobat courtesy of my son Will .. as a birthday present

This had a few advantages

1 – It kept me current , 2 – Refresh on type .. (flown a C150 exactly 1 hour in the last 12 years !) 3 – Familiarisation of Beccles area and 4 – Spinning refresh !

The spinning was awesome … doesn’t take a lot to push her up and over with 2 large ish gentlemen in there 😊

When we got to loops ..my first one just didn’t quite make it over the top … entry speed was 120 but maybe I didn’t pull back hard enough in the first sector … over we went .. on our back and she ran out of ooomph

Flicked over and straight into a spin ….

The well rehearsed spin recovery (I’d refreshed 15 mins earlier) came straight in and we were out in a couple of turns without much G

Great great fun … thanks Will and thanks Stuart 😊👍

Having completed the initial test runs in some baking hot weather .. 34’ no less, I’ve now conducted further ground tests with better conditions and cowls on.

This means the ducting starts to work better and the smaller cylinder head cowls can do their bit .. ducting the air, which has been slightly rammed over the rear cylinder heads and also, through a specially added pipe, directly onto the mags.N

NOTE – Paul HS spotted that my mag brass pipe jets ended about 1” away from the body of the mag. He quite rightly said that would make them less effective as the stream of air around the engine would tend to break that flow … will extend these with sleeved outer .. rather than break he fibreglassed fitting

Once the engine got right up to normal ish running temps .. normal as you can get on the ground … I removed the cowls and found the interior and bulkhead were covered in fresh clean oil.

There was so much that you simply couldn’t see where it was coming from … a lot of cleaning down with de grease spray and rags and try again … and again …

Eventually .. turned out to be next day, I located that it needed to be topping 2400 RPM and pretty warm engine oil … about 60 … both quite tricky on the ground as the cable brakes aren’t too happy holding her at that power for long

Then jumping out and torch in hand to look everywhere … spotted the rear left cylinder … cylinder 4 I think .. most rearward on a Jabiru with its offset crank… had clear oil running down the outside of the rocker tube .. with evidence that possibly both tubes we’re seeping

Looking at the engineering diagrams these alloy tubes run between the engine sump and the rocker head ..the T bar rubber unit takes a pressure central feed he rocker and these tubes run – unpressured – to drain back into the sump having done their stuff and lubricated the rockers.

Hence .. the grunt needed to get it to show .. at anything cool and around fast tickover … it simply doesn’t show

Update … further checks .. located a small drilled hole in each rocker box head … pointing upwards .

. These very small shafts allow any excess oil that overfills the rocker to vent and exit over the cylinder head fins.

This now moves us down the path of … why are the rocker boxes overfilling … further discussion reveals that a larger bore sump feed tube may have been added in place of the normal smaller bore.These w

These will now be replaced with the normal smaller bore and a glass topped rocker cover used to see exactly what is happening under power conditions.

My first aviation engineer was Bob Wright from Jersey Channel Island Aero Services .. I used to love his easy going solid support and guidance ..not making me feel like some oik … muscling in on his profession but embracing, supportive and inclusive

Bob sadly passed away a couple of weeks ago … thank you Bob for all that you freely gave both in skills, friendship and support … I couldn’t have started OR finished without you.

Next was Mike Fleming, who also freely gave huge amounts of time to ‘watch at a distance’ a great skill … to not dive in and show me how it’s done (when all I would have learned was how good HE was at doing it !) but instead, nudge, ask (timely) questions … see if I understood what I was doing and what would then logically follow …. Mike did (and still does) provide context and oversight that meant you felt supported .. and learned from mistakes rather than bury your head in your hands !

Now, in the U.K., I have the pleasure of working with someone like James Milne. A wonderful easy going mine of knowledge and niceness

I could learn something every minute from this guy …. His focused ‘no nonsense’ approach to each and every step and then setting up and driving action to rectify anything is just great to be around.

At the Ranger annual today he spotted that a bevel was not quite as free as it should be .. he followed this through and suspected that he undercarriage had been stressed at some point.

To validate this we needed to get the weight off the undercarriage so, within minutes he was up a ladder, we had moved the aircraft to position it under a main hanger beam. A strop was erected and we had the aircraft floating just above ground level.

We slackened the main u/c pins and then strapped the Left and Right wheel .. so it wouldn’t splay on release, then removed the centre V brace.

Now, with the weight off … you could see and feel the saddle clamps had started to dislodge. I don’t recall any particularly heavy landings .. apart from the first grass one crossing the channel to Sandown …maybe it could have been just 5 years on concrete landings …

Whatever .. it’s been spotted … it’s a relatively easy reconstruct and replace with new parts … 2 brace arms, 2 cross plates, 4 mounting arms .. 4 saddle clamps and a set of nickel rivets