First (ground based) smoke test

With such a sunny weekend it was a good day to remove the front seat cushion and part fill the smoke oil tank .. about 1/5th full .. so enough to cover the ‘clunk’ tank internal feed pickup.

A ‘clunk’ pick up is like my model fuel tanks from when I was a kid .. it’s a pipe with a weighted end so that it always gravitates into where the fuel lays .. technically it means it will still pick up when inverted !

I did an initial ground power test outside the hanger .. fire extinguisher at hand … this proved that none of the feeds, or t bars or injectors had a leak. So we decided to ring the tower in advance of an engine on test as the smoke would, by virtue of where we were, drift across the upwind end of the active (only) runway

Took a bit of explaining as it wasn’t simply a ‘around island check out’ but the ATC kindly humoured me and asked if I wanted fire crew on standby … I felt it may be over the top but didn’t want to dissuade if they fancied a ride out in the sun

Sure enough .. the super helpful fire crew turned up 5. mins later in a land rover check vehicle and a super large bright yellow spray vehicle !

Initial start up and run up to reasonable temps and i selected smoke on.

Will was videoing and had a headset on with the icom standby radio so we could communicate if required. With a thumbs up and smoke on .. nothing was coming through in terms of smoke. So we stopped to investigate

All looked fine but we thought we would break the connector feed and see where the ‘blockage’ was … turns out it wasn’t even making the injector side of the on off valve !

On more detailed inspection it appeared that the one way STOP valve had an arrow on it and it seemed to indicate ‘direction of flow’ and, if so, it was facing the wrong way

A quick break of the metal hard jubilee clip and re jig and re clip with a longer piece of test drain tube .. re open stop valve and turn master on, pump on … and loads of oil !

At this point I walked the firecew through the setup, fitting, switches, safety valves and planned securing method with braided steel tie downs. They said they were very happy with this and would welcome a copy of the spec for their records with some details of oil formulae

Reconnected the system to the aircraft pipe and injector feeds and back in to start engine … ran up to around 350’c and try again … smoke was evident but fairly whispy … tried to up the power, temps but at ground level and not full power it was never going to each the 600-700 of normal operating temp .. so shut down.

Another ground test we carried out was a timed on, off test turning off the continuous button and noting when the (albeit light) smoke stopped … it was almost instant stop .. very clean .. so that’s quite a result as well .. with no delayed residual left in the pipes

At least it all functions and no leaks 😉

Post test investigation revealed a pretty wet bottom … the unburned oil had blow back on the undercarriage and front underside … I suspect at operating temp it will pretty much burn off !

Smoke system – securing

The LAA have asked that the smoke oil tank is secured suitably to withstand .. wait for it .. 9G …

I had planned a slightly more complicated cross over bar arrangement as this would match the aircraft internal structure but then thought … hang on .. this is a bit over engineered

I needed something that was simple to fit .. easy to remove .. easy to stow any elements that would stay permanently in the aircraft and yet be really strong.

The rigging setup on the Sherwood is a,azingly string and yet simple to manufacture so .. decided to use 3mm multi core stranded steel wire .. thimbles and turnbuckles to give me some ‘fit and secure’ flexibility.

All parts are stainless or steel … and it was fun to borrow Bob (Wright’s – CIAS) nicorpess huge pliers again … 3 tonnes of pressure when swaging.

… the quick release crampon means it should be a very neat cockpit fit with no loose flapping bits.

I also started to connect the jumper cables on the switch, fuse, switch and relay … as I have co located the fuses and switch the wires can be cut down to cm …

Just need to decide if I’m going to mount the ‘momentary’ switch to the stick … this is armed once the main smoke switch is thrown … cool eh 🙂

Smoke planning – Part 2

Got up to a very windy hangar today .. force 8 outside .. and the time to offer up the oil tank to the front seat

Then .. try it with stick full back

Then to offer up the injectors .. these are high quality parts with all the fittings provided by Smokin Airplanes …

Making sure that the braided oil lines are placed to offer the line of least resistance and sit nicely against the exhausts

Running PTFE tape around the threads

Good chance to have a look around the engine after the last 15 hours or so .

Paul from TLAC has kindly provided some useful input figures that I didn’t have for this MOD .. to aid calculating the ‘G’ factors in respect of ‘crash load’ I need the following

Forward and Rearward load = x 9

Vertical up and down load = x 6

Side to side load = x 4.5

So .. with a tank and pump combined weigh of 19.7kg

Forward = 19.7 x 9 = 177.3

Vertical = 19.7 x 6 = 118.2

Side = 19.7 x 4.5 = 88.65

Some cold winter flying – Steep turns

Been out practicing in this cold cold weather .. but it’s lovely and calm so .. time for some steep turns and practicing

Managed to get held and was around number 7 to land so had a chance to throw her around near Elizabeth Castle for about 30 mins

2019 – New Year Resolution – Take up Smoking !

Many years ago … quite some time before I had finished the build I had the idealistic idea that I could try to spice up the display options by adding a smoke system. I researched the market and located a US form called smokin airplanes and ordered their smaller kit.

I plumbed some of the parts in during the latter parts of the build … aeroquip oil pipes and wires etc and potential pump mounts and fillers but … on approaching the LAA discovereed the challenges of adding to the existing certification … they needed paperwork and workings to demonstrate the whole fit could withstand 9G !

After a couple of attempts at submitting it was clear it was going to delay standard test flying certification .. so I stopped further work on it.

Now .. 2 years after test flying certification .. I’m looking at resurrecting the work.

NOTE .. the following is all to do a proof of concept fit on the ground and test run it terra firma prior to blowing the dust of my pre submission LAA MOD form

Tuesday 1st January -2019

Spent a ‘happy’ hour upside down in the front cockpit checking the items i put in 2 years ago that were all neatly cable tied off.

The initial bit is to connect the oil feeder pipe to the back of the beautifully blue anodised T bar on the bulkhead. I’ve gone for the smoke model that has 2 (atomiser) spray heads .. one for each exhaust. Smokin Airplanes specify a specific distance from the exhaust tail pipe for these to be mounted (10” from tail exit I seem to remember)

Once I knew it would hold up test flying I took most of the fittings out and capped the exhaust holes, that was 2 years ago.

To mount the oil reservoir /tank I had originally intended on making a small rear shelf to sit behind the pilot seat P1 – rear, and span the sides of the fuselage … secured with proper aviation bolts. There was also a rear fill easy access, including an overflow drain pipe that exited well clear of any part of the airframe underneath the pilot seat.

Now, 2 years on, I realise it would be miles easier to simply place the oil reservoir in the front seat position ie P2. The plan now is to put simple extenders on the existing seat bolts and have rivnuts on the end to allow an ‘over the top’ cradle to be manufactured and hold the plastic oil reservoir tank securely in position.

The oil tank I bought is one of the smallest and measures 28cm wide by 28 cm deep and approx 28cm high – which includes the top mounted filler nozzle. The (not insignificant) pump adds around 10cm to the dimension .. be it side, end or top mounted.

The pump looks like it’s built to power a small airliner ! Def quality stuff but pretty heavy … another reason for re-locating this to the front seat location where weight will not be a problem. Also as a full oil tank runs down there will be zero effect on the C of G as the whole tank and pump pretty much sit on the main spar position.

I plan to make a support (spider) cradle to give me 4 solid fixing points for the oil tank/pump combination and then run a temp electrical test connect to trial it.

The electrics are largely provided with a nice mini panel, arm switch and light indicator .. the aim being, that once selected .. the system is ‘armed’ and then a short presss of a red ‘press and hold’ button and the oil would pump…

The installation guide provided by Smokin Airplanes is super clear and they are really helpful and respond very quickly to any queries via email

….to be continued ….

Landing focus

With the various ‘versions’ of weather we have had over recent weeks I’m going to do some clips of different landings …now Sam has shown me how to clip the videos … 

Some are ok .. some I can learn from 😁

First one .. Two up and just rounding out with a bit of cross wind surprising me as I pass the lee of the aeroclub .. so quite a bit of late aileron 

Second one … one up … nice calm conditions and steady approach to a touch and go 

Third one .. Bad weather (close) 3 min circuit .. BUT .. messed up the round out and approached too quickly … so you see she lands and then the starboard wing tip just starts to lift .. settles … then does it again … just to prove .. It ain’t all over ‘til it’s in the hanger with the covers on !!! 

Fourth one .. which was actually my FIRST ever landing in the Sherwood on grass 

Slight update to WordPress .. new features

Getting used to the slight update in WordPress now I’m paying a little for the software …

I’m going to try to use highlighters for quick reading .. also use pink when it’s something to watch out for or learn 😊

Not sure if these features are easy to retro add .. but we’ll see 

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