Simple and efficient

One reaction I got on my video was a suggestion on a very simple and efficient system to retain/secure the spark plug caps.
4 washers grinded down to oval shape, 2 holes in each washer and a piece of 4mm bungee cord…Adopted and implemented, thank you MichaeL!

An autumn flight to a nearby field

Some views of the engine when I drain the excess oil from the cylinders, some engine sound when starting up. The rest is just for your eyes...

The perfect excuse for a long flight...

The Pyrenees

A few weeks ago I had to go down to the south of France by the Pyrenees.  How fun is a 6 hour drive without the family on a crowded motorway and then the same way back again? Humm... but there is a field next to where I’m going… and the people I should meet could pick me up… I could bring my tent and fly back the next day… sounds like a plan… With an excellent weather forecast this was a perfect excuse for doing a long flight.

Camping at the local flying club

9h10 in the air, 1156 km according to my GPS, i.e. an average speed of 126 km/h (78 mph).  Constantly running on 5400 RPM, this is higher RPM (and higher speed) than what I use to do but with that kind of distance… Consumption was 16 l/h but more relevant might be consumption over distance: 12,6 liters for 100km. Compared to my rotax this is a 20% reduction in consumption and a gain of 15km/h.
I will come back to more detailed consumptions for evening “sightseeing” flights. However, I’m convinced that I have the almost optimum pitch setting between power and speed on my WarpDrive and if I want to get more out of the engine I will need to get another prop. But that will be for next year.

Millau Viaduct - so tempting but so forbidden... 

I now have 17h30 on the engine. No bad surprises whatsoever. My Victor 2 was running smoothly. I still have some vibrations at low RPM but at higher RPM she is steady as a rock and very reactive. If not running for over a week I need to clean the sparkplugs as they fill up with oil – I try to see it as an opportunity to make an additional engine visit at pre flight.

Home again

And I saved time... less than 4 hours in the air to get there while it would have been 6 hours in the car...

Another flight another pitch...

I did fly a few days ago, not very long but with a slightly reduced pitch. I have the feeling I found the good compromise between power and speed. It felt right, the plane was lively and very responsive on throttle. Estimated consumption 14l/h but it was short flight.

I’m waiting for Simonini’s feedback on my EGT and CHT to see if the will recommend change of carburettor jets.

This coming weekend I have planned a longer trip to the south of France (4h30 each direction at least).

Side note - Stress testing Oratex UL 600

About a year ago I discovered the existence if a new kind of fabric for covering light aircraft. It is an iron-on polyester fabric very much like what is used for model aircrafts. I contacted the company (http://www.oracover.de) and they proposed to send me a free sample of Oratex 600 UL in the colour of my choice. At that time I was thinking that when re-covering my Avid Flyer it would be yellow so I asked for Cub Yellow.

Oratex is glued to the construction with a thermo activated glue (hot melt). It looks like white glue and smells about the same, i.e. almost nothing compared to traditional glue for covering fabric. The glue should dry before applying the fabric and it is then activated through the fabric with an iron. The tension is obtained with a heat gun. Finished, no paint, no nothing!
Compared to the pain of traditional covering (glue, fabric, dope, UV protection, primer and topcoat in multiple layers) and a total weight of 110-130 g/m² this sound too good to be true... 

Just like with the Simonini engine the question is "will it age well?".

To make an extreme aging test I made and covered 3 small profiled frames (20cm * 17cm). On each of the covered frames I glued a rectangle of fabric like for a reinforcement or repair. The first frame stayed in my office without receiving any direct sunlight.

The 2 frames mounted outside

The second frame was mounted outside but under a protecting roof. Facing south and exposed to sun and wind all day but fairly well protected from rain and snow. The third frame was mounted outside but without any protection. Facing south and exposed to sun, wind, rain and snow…

The frames were left for 9 months from the beginning of December 2010 to the beginning of September 2011 (somewhere between Lyon and Grenoble, France, with an average of 2000 hours of sun per year). We had a lot of snow during the winter, rain in the spring and a lot of sun and strong heat during the summer.

9 months, 1500 hours of sun, equals 100 hours per year for 15 years. I’m happy the years I get 100 hours in the air...

So, after 9 months I took in the frames and cleaned them (regular dishwashing liquid, warm water and a soft brush). This is what they looked like:

Reference frame                 Protected under roof                Fully exposed   

My reference frame, the one that had been sitting on my desk, didn't show any sign of aging at all. Anything else would have been very surprising and put a rapid end to the test... 

The second frame came out smelling like a rose...

After sitting in the sun, but under a protecting roof, during 9 months it was in so good condition that it was almost only the holes from mounting it on the wall that visually differentiated it from the reference frame. I can hardly see any difference in colour between this one and the reference frame. The fabric sticks just as well to both other fabric and to the frame as on the reference frame.

The third frame had suffered badly (but what else to expect?). 

Water, from rain and snow, had made its way inside the frame. The frame itself and the fabric shows sign of mould. Where there was mould the fabric would no longer stick when glued onto fabric and stick noticeably less, or not at all, where glued directly to the wooden frame. It is also very difficult to get the fabric clean. 

It should be noted that the square patch has suffered much less as being less exposed to the permanent moisture accumulated in the wood.

The Oratex fabric is surprisingly resistant to penetration (much stronger than my current traditional covering).
I have without success tried to penetrate the fabric by pushing my thumb (nail first) as hard as I could at the centre of the frames. My thumb hurt but the fabric resisted on all 3 frames...

Penetration with a sharper object (a BIC crystal medium point) is possible and there is a difference in resistance between the frames. 

The fabric on the reference frame is penetrated by the pencil at a pressure of 2 kg. The fabric on the second frame offers slightly less resistance: ~1,6 kg, while the fabric on the third, fully exposed, frame breaks at just under 1 kg.
 
It is difficult to compare this with traditional covering as I don't have a sample frame, but when I (by mistake) put a screwdriver through the side of my plane I didn't have the impression of using much force. To put the same screwdriver through even the third frame takes significant pressure. I feel confident saying that even the fabric on the third frame offers better resistance to penetration than what I have today.

The second frame, exposed to sun and wind for 9 months, could probably be said to be the most representative or realistic of the 3. I don’t normally leave my plane outside in bad weather except when travelling and not having a choice (and it would not be snow and ice, only occasional rain).

I'm impressed by the result of this stress test and will definitely consider this as a most interesting alternative when I decide to re-cover my plane (not this winter, but maybe next...). 
But I think I will do it white...

2% oil mixture

Enzo Simonini has confirmed by email that 2% oil mixture is sufficient under the condition of using a high quality 2 stroke oil. As the user  manual says 3% this will be a 33% reduction (and economy)...

I'm back - and updating...

Sorry about a long silence... Holidays are over and I’m back. 

I have done one flight with a slightly increased pitch, I have now found the upper limit and will have to reduce it again... I’m seriously thinking that there might be a better prop for this engine somewhere than the one I currently have. Consumption was still about 14 l/h but this time with poor takeoff performance and no significant gain in speed. Maximum RPM was also too low.

I will soon be posting an – I hope – interesting side note... watch out for it!

More flights...

I have done some more flying, adding another 2.5 hours. For the last hour I added another 3° degree of pitch (i.e. total 7° more than with the 532). It made almost more difference than the first 4° degrees. I can now outrun my airspeed indicator at level flight (limited to 150 km/h - 93mph)!

With cool air just after the rain I still have a 6050 RPM maximum. Comfortable cruising speed 110-120 km/h around 4800RPM.

Takeoff is still very good so I will try another 1-2° pitch before doing serious fuel consumption estimations.

Second flight

I did fly last Friday as planned. Rather windy and with strong thermals, i.e. not the ideal conditions to make precise performance or consumption measurements.

For the next flight I will do some prop adjustments by increasing the pitch even more. I know little about props but I have the feeling I don’t get the most out of the current setup. 

The first consumption number after 1 hour flight in rough conditions is ~13 l/h (3.4 gallons US/hour).  This is 25% less than my 532 at comparable speed (but with incomparable takeoff and climb performance). However, don’t consider this as final numbers!