This blog covers the construction and flying of a Van’s AircraftRV–8, built and flown by Kevin Horton.
I had thoughts of someday building my own aircraft from the time I was a teenager, but never took it beyond the fantasy stage until after arriving at Cold Lake, Alberta as a freshly minted test pilot. One of the other test pilots there was building an RV–4, and he told me fantastical tales of the performance and flying qualities. I did some research, and learned that Richard Van Grunsven (Van), had designed a very well loved all-metal single seater, the RV–3, followed by the two-place tandem RV–4, and the two-place side-by-side RV–6, all with tail-wheel landing gear. And then the RV–6A, with tricycle landing gear. All models had a good all-round performance and were reputed to have excellent handling. I was tempted, but the time wasn’t right. As always, there were one or two things to get done in life first, and then the time would be perfect.
A few years passed, and I eventually realized that as soon as you got one of those roadblocks out of the way another one appeared, and the “perfect time” never arrived. If you wanted to get something done in life, you just needed to get started.
One day I learned that Van had come out with the RV–8, which was two-seat tandem like the RV–4, but with much more baggage space, 10 gallons more fuel and a wider cockpit and instrument panel. I had visions of quite a bit of cross country flying, possibly in Instrument Flight Rules (IFR), so baggage space, fuel capacity and a large instrument panel were all attractive. This was the trigger I needed to get off my butt and start this grand project. I did a demo ride at Oshkosh in 1997, and was very happy with the aircraft, so I ordered the tail kit.
I looked at the tail kit as the litmus test - I would use it to see if I enjoyed the building process. If I did, I would continue. If not, I would sell the tail kit and drop the idea of building an aircraft. I found that the building process was very enjoyable, and was good way to relieve stress after a busy day at work. I carried on, doing a bit at a time, like the proverbial mouse eating the elephant. And one day, many years later, I had an aircraft. And it flew.
Construction started in the fall of 1997, and first flight was almost 11 years later in August 2008. The beautiful Golden Hawkspaint scheme was finally done in the spring of 2010.
The aircraft has about 230 hours on it now (May 2013), and Terry and I have finally started to do some regular traveling with it. We took it to the huge EAA Fly-In at Oshkosh, WI in 2010 and 2011. I got to Sun n Fun in 2012, and we have flow it to Nova Scotia and Wisconsin several times. I try to fly the aircraft every week that I am home, if the weather cooperates.
Wednesday, December 11 2013 @ 07:42 PM EST Contributed by: Kevin Horton Views: 8
Today would have been a great day to be flying east to visit my folks in Yarmouth, at least as far as the winds go - over 35 kt tailwind at 9000 ft, and if we donned the oxygen masks and climbed up to 17,000 ft we’d have almost 80 kt tailwind. Predicted enroute time of 2:10 at 17,000 ft for the 464 nm flight to Yarmouth. Wow! It would be a long flight westbound though - 3:40 home, at 8,000 ft.
Sunday, December 01 2013 @ 07:03 PM EST Contributed by: Kevin Horton Views: 20
Last weekend the weather was lousy, so I didn’t get flying. But yesterday morning was acceptable, if cold, so I took advantage. It was the first real cold day this winter flying season, with a temperature of about –14°C at engine start. But first, I had to clear a bunch of snow from in front of the hangar, which meant I really hoped to get the snow blower to start, probably for the first time since last winter. Fortunately it has an electric starter, powered by an extension cord plugged into 120 VAC. It took a lot of cranking, but I finally got it to run. I was very happy that it didn’t have a pull starter, as I’d have been close to dead by the time it got going.
The flight itself was short, dedicated to a few aerobatics, and two landings. The engine puts out a lot more power in the cold air, and I used it to do some vertical eights (picture two balls, one on top of the other).
Sunday, November 17 2013 @ 08:30 PM EST Contributed by: Kevin Horton Views: 22
Last week was a good week. Wednesday several of us flew to Winnipeg in one of Transport Canada’s C550s to do a day of AeroMedical Training on Thursday, at the Canadian Forces School of Survival and AeroMedical Training (CFSSAT). The highlight, and the whole reason we went, were the hypoxia demonstrations in the pressure chamber. We do quite a bit of flying in pressurized aircraft at high altitude, and there is always a risk of a loss of cabin pressure. Thus it is very smart to be familiar with your personal hypoxia symptoms, to increase the odds that you will recognize the situation and don the oxygen mask before it is too late.
In the past, the hypoxia demos were done at 25,000 ft or 43,000 ft cabin altitude in the pressure chamber. Large vacuum pumps reduce the pressure in the pressure chamber to produce a cabin pressure that is equivalent to the low pressure found at altitude. The human body is not designed for such low pressures, and there is a real risk of decompression sickness at 25,000 ft and above if this altitude is reached quickly, caused by nitrogen coming out of solution and forming bubbles in the body. CFSSAT has changed their training protocol since I was there last - now the hypoxia demos are done at 10,000 ft cabin altitude, with the training wearing a mask and breathing a gas mix which is 10% oxygen and 90% nitrogen, vs the normal 21% oxygen, 78% nitrogen and 1% other gasses. The combination of higher altitude and lower oxygen percentage is equivalent to 25,000 ft. This new protocol is much easier on the body.
I learned that my hypoxia symptoms have changed slightly as I aged. In the past, the first sign was always a tingling sensation on the back of my palms, followed by a feeling of confusion as the brain started to be starved of oxygen. We each did two hypoxia events on Thursday, and in both cases the first noticeable symptom was confusion - no tingling of the hands either time.
Friday we flew home. Only two of us were qualified on the C550, so I was up front on both Wednesday and Thursday.
Saturday morning I did a short flight in the RV–8 to warm up the engine, then I pulled the cowlings to check the cylinder compression, check the ignition timing, etc, as part of the annual inspection. No major issues were noted.
Sunday, November 03 2013 @ 07:10 PM EST Contributed by: Kevin Horton Views: 40
The weather last weekend was not great, so I didn’t get flying. But today was quite nice, so I took full advantage.
When I was cleaning the bugs off after the flight, I noted a bit of oil on the belly. I’ll have to pull the cowlings again to check to see if I have an oil leak.
When I was under the belly cleaning off the little bit of oil, I saw a line of blue fuel dye going back along the bottom wing skin from the inboard end of the right fuel tank. The dye stain came off easily, so I suspect it was probably from today’s flight. I had noted signs of a tiny fuel leak in early 2013, and had been watching this area. It looked like it had stopped for a long time, then a few months ago I started seeing hints of blue dye if I removed the intersection fairing so I could see the end of the fuel tank. But now I can see it on the wing itself, so it must be getting worse. I’ll have to pull the tank off soon so I can deal with it. Drat.
Sunday, October 20 2013 @ 05:11 PM EDT Contributed by: Kevin Horton Views: 42
We’re at the end of the colourful fall leaves season. The leaves in this area are mostly on the ground, but I noted when driving back from Montreal on Thursday that there were still many leaves left in Quebec. Terry and I hoped to fly to Trois-Rivičres for lunch today, but we had a cold front go through, and the winds were gusting to 30 kt in that area this morning. There was also much more low cloud up there than expected, which meant that we wouldn’t get to see many of the leaves. Lunch plans - cancelled.
I went flying anyway, as it was a nice day in this area, but windy. Terry wouldn’t enjoy getting bounced around in the bumps, so I went solo. I headed east from Smiths Falls, at 2000 ft, below a broken layer of cloud, and went counter clockwise around Ottawa. There were still a few red leaves hanging on in Gatineau Park, north of Ottawa. This will be the last fall leave viewing flight, as the high winds will certainly put many of the remaining ones on the ground.
Sunday, September 29 2013 @ 08:55 PM EDT Contributed by: Kevin Horton Views: 44
It was a beautiful fall day today, and the leaves are starting to show their colours, so I went flying to have a look. We’re still a week or more from peak colours, but it was still worth the flight. I was in no rush, so I toddled along at 125 kt TAS, burning 5.2 GPH.
Sunday, September 29 2013 @ 08:44 PM EDT Contributed by: Kevin Horton Views: 47
I spent a few hours this week correcting the climb test data to standard temperature and 1800 lb gross weight. I used the Density Altitude method, as described in FAA Advisory Circular 23–8C, Flight Test Guide for Certification of Part 23 Airplanes.
Data from the 2500 ft pressure altitude point, corrected to 2821 ft density altitude. The temperature on 25 Sept was warmer than standard, so the density altitude was higher than the test pressure altitude.
Data from the 4500 ft pressure altitude point, corrected to 4412 ft density altitude. The temperature on 14 Sept was colder than standard, so the density altitude was lower than the test pressure altitude.
Data from the 11,000 ft pressure altitude point, corrected to 11,920 ft density altitude.
Data from the 17,000 ft pressure altitude point, corrected to 18,570 ft density altitude. I was happy to see that the corrected data for the tests at 17,000 ft makes a bit better, if still ugly, curve than the original raw data.
The four test points fall fairly close to a straight line. If I project that straight line to sea level, I get a rate of climb of 1807 ft/mn.
Note that the prop governor is giving 2650 rpm once the oil warms up. I looked at adjusting it to give 2700 rpm, but the actuating arm is hitting the stop. I would need to move the arm on its splined shaft, and the access back there is poor enough that I decided to leave things alone. The engine would make about 4 more hp at sea level if it was running at 2700 rpm, and that extra power would give about an extra 53 ft/mn rate of climb, giving 1860 ft/mn. Vans Aircraft claims 1900 ft/mn, and all their rate of climb specs are rounded off to the nearest 100 ft/mn, so my results are consistent with their performance claims.
Friday, September 27 2013 @ 09:09 PM EDT Contributed by: Kevin Horton Views: 55
The weather was perfect on Wednesday, and I had nothing pressing scheduled at work, so I took the day off to do more climb testing. I got airborne shortly after sunrise to catch the early morning smooth air. I did eight climbs from 1500 ft to 3500 ft, with speeds from 58 KIAS to 130 KIAS. The raw data looks very good, and shows the classical curve of rate of climb vs speed.
I gassed up, turned on the oxygen system, and climbed up to 17,000 ft to do some high altitude climb testing. I donned the cannula as I climbed through 10,000 ft.
I should have paid more attention to the predicted temperature at altitude, as it was a lot warmer up there than I had anticipated (about 14 deg C warmer than standard temperature). The extremely warm temperature reduced the engine power, and impacted the rate of climb. The density altitude at the end of each climb was over 19,000 ft. Many of the 1000 ft climbs took over 3 minutes, with the longest taking over 4 minutes. I was not able to do any climbs at low airspeed, as the oil temperature would get too high in the late part of the climb. The aircraft was very delicate to fly, and it was difficult to accurate hold a constant airspeed.
The resulting data of rate of climb vs airspeed isn’t nearly as pretty as the lower altitude data. I’ve got a pretty good idea what the maximum rate of climn was, but no idea what the airspeed for best rate of climb was. In retrospect, it would have been more productive to do the climbs at a bit lower altitude, as the higher rate of climb may have allowed climbs at lower airspeed to flesh out the left side of the curve.
I had wondered whether it would be practical to cruise at 17,000 ft. I concluded from this flight that it is possible, but only worth it if the high alitude allows taking advantage of very strong tailwinds, or a much shorter route.
Saturday, September 21 2013 @ 04:49 PM EDT Contributed by: Kevin Horton Views: 51
I did two climb performance flights six days ago, on Saturday, 14 Sept. I meant to post about them earlier, but we had family visiting, which ate up most of my spare time.
I had done some climb performance testing shortly after the first flight, in 2008. But that was with the original Hartzell prop, and I had never done any similar tests with the current MT prop. The weather was clear on Saturday, and the temperature was fairly close to standard (15 deg C at sea level), so I decided to have a go at this.
I used some cheap exercise weights as ballast, in a very tough military duffle bag, strapped down in the rear seat. Additional ballast went in the forward baggage area, to get the take-off weight up to about 1835 lb. The design gross weight is 1800 lb, so I wanted get data at that weight. The weight decreases as the fuel is burned during the test flight, so the starting weight must be above 1800 lb. I have approval to fly at up to 1900 lb.
I had hoped to get climb data starting as low as 1000 ft above ground level, but the surface winds gusting to 15 or more knots created too much low altitude turbulence to allow good quality testing. I finally found smooth air from 3000 ft and up, so I chose a test block of 3500 ft to 5500 ft. I timed two climbs at speeds from 60 kt to 130 kt, in 10 kt increments. The winds were predicted to be from 340 degrees, so the two climbs at each speed were at 070 and 250 degrees, to put the wind on the wing tip. I averaged the rates of climb from each of the two runs at each speed.
The raw data from the morning flight at an average test altitude of 4500 ft shows the classical variation of rate of climb with airspeed. The maximum rate of climb would be at approximately 96 kt, but the curve has a fairly flat top, so the rate of climb is within 95% of the maximum from 82 kt to 111 kt.
After lunch I gassed up, and did another series of climbs from 10,000 ft to 12,000 ft. The speed for maximum rate of climb decreased as the altitude increased, as expected. At 11,000 ft, the speed for maximum rate of climb has decreased to 87 kt.
I also had my ancient PowerBook G4 running to record data, so I’ll look at that to hopefully get a bit cleaner curve of rate of climb vs speed. I’ll also correct the results to 1800 lb and standard temperature.
I hope to get another set of data at higher altitude in the next week. I’ll turn on the oxygen and do some climbs around 17000 ft.