One Rivet At A Time

Welcome to Kevin Horton's RV-8 Project
Thursday, January 29 2015 @ 03:15 AM EST

Big Picture

This blog covers the construction and flying of a Van’s Aircraft RV–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 Hawks paint 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.

Scroll down for the latest detailed news.

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IFR Practice Flight + Annual Inspection Progress

General News

I was scheduled to be on standby all day Saturday, which meant I would need to stick close to home. The weather was quite nice on Friday, so I took that day off to do the things I wouldnít be able to do while on standby, such as go to the airport.

I had a great IFR practice flight in the RVĖ8 in the morning, then made more progress on the annual inspection. I found a couple of loose fasteners, and the tail navigation light is unserviceable. I only require that light if Iím night flying, which I avoid like the plague, given the difficulty of executing a successful forced landing at night, so Iíll defer sorting out that nav light until the weather is warmer. Hopefully it is just a burned out light bulb.

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Flying Again, Finally

General News

Iím owed several days of compensatory leave to make up for overtime Iíve worked in the past year, and yesterday was forecast to be unseasonably warm, so I used one of those days. I got the repaired plenum chamber mounting flange reinstalled. I had hoped at one point to also get a flight off yesterday, but it snowed off and on all day, so that was not possible.

Today was forecast to be clear and cold, with very light winds, so I took another day off. The runway is almost 100% ice covered, from the freezing rain we got a couple of weeks ago, so I only dare fly when there is minimal crosswind. They were still clearing yesterdayís snow off the runway when I arrived, so I had to wait until after lunch. The first trick was getting the Mooney that was by the door of the hangar out of the way, which means pulling it out onto the taxiway.

The Mooney is too heavy for me to push it around by hand, so I used the gas powered PowerTow tug that connects to the nose wheel. It usually works very well, but the combination of a bit of crown on the taxiway plus the ice was more than it could handle. All it would do was spin its wheel. James are Floyd spotted my struggle from the club house, and graciously drove down to lend a hand. The three of us pushing were just enough to get the Mooney in and out, so the RVĖ8 could escape the hangar. Thanks guys!

The delay while the runway was cleared and I fought with the ice meant that the engine had been preheated a lot longer than I anticipated. I failed to appreciate the implications as I attempted a start, and I primed the engine as if it was quite cold. I didnít fire, so I primed it some more. I realize now that I had almost certainly overprimed it and flooded it, but I didnít figure this out until I had ran the battery down. Back in the hangar for two hours on the battery charger, then it started right up (with a lot less priming). It was great to finally get flying.

The wind stayed down while I was flying, which was a relief. It slid around a bit during the landing roll, but a quick touch of rudder got the nose pointed back in the right direction again, and I was very happy when it finally rolled to a stop, still on the runway.

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Plenum Chamber Support Flange Repair

Engine Installation

We took Porter Airlines to Halifax, NS, then rented a car and drove to Yarmouth, NS for a week over Christmas. It was great to see my parents and sister again.

Just before leaving for Yarmouth, I started the annual inspection on the aircraft, starting ahead of the firewall. I found a cracked flange that supports the plenum chamber top on the right side at the cowl air inlet. The left side had the same failure a couple of years ago. I reinforced that area on the left side when I repaired it, but I didn’t make any changes on the right side, as I couldn’t get good enough access to do the work in situ, and it is a pain to remove the parts. I rolled the dice that the right side would be OK, and I lost that bet.

The bit that broke off.

I’ve got the repair mostly done now, but we’re going into a bit of a deep freeze now (a cold front went through today, and the forecast low for Wednesday night is –30įC), so it’ll have to wait until we’ve warmed back up again before I do any more work in the hangar. I’ve worked in the hangar at –17įC - that is just workable, with two electric radiant heaters pointing at me, but I wouldn’t want to go colder than that.

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Yet Another Web Site Host

General News

The web site has moved to yet another web host, Arvixe. I had been on the same host since the web site was created in 1997, but that host had become unreliable. In retrospect, I didn’t do as much research as I should have before moving to the second host, and that host quickly proved unsuitable. Arvixe seems to be the best host yet - hopefully they’ll stand the test of time.

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Winter Has Arrived

General News

Winter definitely arrived last week, with several days of snow, with roughly 20 cm of total snow fall. I headed out to the hangar Saturday AM to get the snow blower going and clear the snow. I had started it about three weeks ago, to make sure that it had survived its summer of hibernation - that first start was a definite struggle, so I wasn’t sure what to expect this time. I got lucky - it started right up. It took about an hour to blow the snow off the entry to the hangar, chip a few big ice ridges from where the airport snow plow had turned around, and clean up with a shovel.

The ceiling was low when I arrived at the airport, but it had cleared out nicely by the time I was done clearing snow, so I rewarded myself by going flying.

Many of the lakes have frozen over, but the ice is still way too thin for any intrepid ice fishermen to set up camp.

Some other lakes have quite a bit of water flowing through them, as they are part of the Rideau River system, so they haven’t frozen over yet.

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More Stall Speed Testing

Flight Test

We had a nice sunny day today, so I went flying. Last time I flew, I did some stall speed testing, using an experimental four leg GPS method, and I was puzzled that the results were about 3.5 kt different from the earlier testing I had done using the same method. After thinking about it a bit, I realized that I had possibly done the stalls with the mixture set differently than from the earlier flight, and that this might possibly have resulted in a different idle speed, and a different effect from prop discing drag. I wanted to investigate this today.

We were under the influence of a strong high pressure area, with the Ottawa altimeter setting at 30.81, and fairly cool temperatures (Ė10įC or 14įF), so the density altitude at Smiths Falls was very low (3200 ft below sea level, or about 10% higher density than sea level with standard temperature). The plane was a veritable rocket ship under these conditions, reaching over 140 kt before the end of the 4000 ft runway.

The air was smooth, so I did my testing at 4500 ft barometric altitude (about 3700 ft pressure altitude). First, I did numerous stalls with mixture at full rich, and then repeated with the mixture set to roughly where I remembered it from the previous flight. I noted that the stall IAS was about 3 kt lower with the mixture rich than it was with the mixture leaned. The engine rpm at the stall was about 80 rpm lower with the mixture rich than with it leaned, which supports my theory that variations in prop discing drag signficantly affect the airflow over the inboard wing, leading to variations in stall speed.

Then I did four four-sided box pattern stalls (i.e. 16 more stalls) with the mixture rich - the results, when corrected to 1800 lb weight, are in between the results from the previous two flights. I suspect the engine idle rpm at the stall may vary with altitude, which may affect the stall speed on my aircraft. Iíll continue the science project on future flights, doing testing at a range of altitudes.

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General News

I got the Geeklog downloads plugin installed and working, and have begun to add the downloads from the other host. I’ll add the remaining files over the next few days. You’ll find them in the Downloads section. New files added will be visible in the What’s New block over on the right.

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Stall Speed Testing

Flight Test

I had day off on Friday, and took advantage by doing a firewall forward inspection and then a short flight. I finally had weather that allowed me to climb high enough to gather some more stall speed data using a four leg GPS method. The results from this flight is a real puzzle when compared to the previous test a few flights ago.

The two test points (four legs each) looked to be excellent quality, with extremely low standard deviation of the four calculations from each test point (0.2 kt and 0.0 kt for the two test points). The two test points gave similar speeds, with only 0.1 kt difference between the two points.

The two test points on the earlier flight also appeared to be reasonably high quality, with low standard deviation (0.8 kt and 0.2 kt). The two test points on that flight giving results within 0.3 kt of each other. But, if I correct the stall speeds from the two flights to the same weight, the stall speeds from Fridayís flight are about 3.5 kt faster than the stall speeds from the earlier flight.

My aircraft has a three blade MT aerobatic prop, and it has a huge amount of prop discing drag with the throttle is at idle, with the prop control fully forward. I suspect that the airflow over the inboard wing is disturbed in this condition, and that results in the stall speed being several kt faster than other RVs with more typical props. I donít recall where the mixture control was during the stalls on the earlier flight, where the stalls were about 2000 ft higher (7000 ft vs 5000 ft). I wonder if the rpm at idle, and thus the discing drag, might vary depending on where the mixture control was. Iíll experiment with this on the next opportunity to try to get to the bottom of this puzzle.

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New User Registration Working

General NewsI found and fixed the problem with new user registration. †It should be working now.
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New User Registration Broken

General NewsNew user registration seems to be broken at the moment. †I'm looking into it.
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