RF5B Motorglider - N99809



Sportavia RF5B Sperber
(Taking off from 2008 Arlington Fly-in, photo by Bob Johnson)


I have flown small aircraft on and off since 1978. In 2003-2004 I was having trouble scheduling airplanes through a flying club, so I decided that if I wanted to keep flying, owning an airplane was the solution.

In late 2005 or early 2006, I found N99809 through a web search. I had been looking for my own airplane for almost a year. I knew that most of my flying would be just a few hours on nice afternoons, but I did want to be able to travel longer distances if I wanted. With many short flights, I guessed that within a year or two, I would have gone everywhere I could go within a few hours…multiple times. So, I was concerned that a conventional aircraft would become tedious.

Eliminating alternatives
What I really wanted was a 1929 TravelAir or Waco biplane. But talking to biplane owners made it clear that they spent most of their time working on the airplanes (some of this may have been a personal choice). You had to slip on final if you were going to see the runway for landing. I kept reading how parts were getting harder to find for the older radial engines, and there were fewer people to rebuild them. Owners reported burning 12-16 gph to achieve 80-90mph. This would make flights relatively expensive. And the 4:1 L/D was a concern. At one point, I paid for a ride in a Waco. While flying along, I asked the age-old-CFI question, "If the engine quit, how far could we glide?" The pilot just laughed and said, "Hell, just throw a brick over the side and we'll fly formation with it to the ground. Don't expect to be glidin' anywhere." Logic trumped emotion and I moved on to find something more efficient and practical. [sigh]

My interest in biplanes made it clear to me that I did like vintage construction. While some pilots really like composite or metal, I tend to be drawn to wood and rag, or tube and rag construction.

I had grown up sailing and knew that you could keep your interest in a sailboat on a small lake far longer than you can keep your interest in a motorboat on the same lake. Soaring was a possibility. But there were no glider clubs within a reasonable driving distance and a glider really wasn't a traveling machine. But a motorglider might be an option.

Motorgliders with small "sustainer" engines on pods had just enough power to take off, gain modest altitude, then shut off for soaring. These would give me the best soaring experience. But it wasn't an airplane you would choose for a cross-country trip. But a touring motorglider (like a Ximango or Diamond Xtreme) would actually let me go somewhere. Not fast, but doable.

A key differentiation is whether you're getting an aircraft for recreation or transportation. If recreation, it can be simpler, slower and cheaper to own for regional flying in nice weather. The more you want it for transportation, the more expensive and complex it becomes. I clearly had a vision of recreation, so the relatively modest speeds of motorgliders weren't an issue.

I liked the Xtreme a little better, but the wings didn't fold well (at that time), so it had to be tied down outside or put in a ridiculously large hangar. The problem was that both of those gliders were expensive ($80K - $180K). Even if I had the money in the bank, spending that much money on entertainment made me uncomfortable. So, a Grob 109 seemed a better choice. But the ones I saw for sale were in pretty rough shape. So -- more searching.

Found it
I'd love to claim that I found N99809 through a careful, strategic search of design alternatives. Uh...not really. Via one of many general Internet searches for "motorgliders," I happened across N99809 on its sales website. [cue, wolf whistle] What a looker! I thought it was just great looking…but assumed it was too exotic and would cost too much. After seeing it still for sale after a seemingly long time, I decided to call Dave McConeghey, the sales agent listed in the ad. Dave turned out to be a great guy, a many-thousand-hour ATP and a CFI-G representing the owner. The price was more reasonable than I expected (about the price of a VW Passat); the design and construction more interesting than I expected.

The fuselage was wood. Wings were wood with cloth covering. So, it had a vintage feel to it, yet it was constructed in 1975, so it would use current materials, parts and glues. The engine was a Limbach, so rebuilding it would be cheaper than a Lycoming. It flew about 85-95mph at 2.5-3 gph. So it was economical and had the overall performance right in line with some of the vintage aircraft that I found acceptable. With a 28:1 L/D, it was much safer in an engine-out situation. I am cautious about landing and stall speeds. If you have to come in fast, off-airport landings are going to hurt: at least your pocket book and most likely, you. But the RF5B stalled at 42 mph, so it could come in quite slowly. No significant AD's. It all looked really good.

If it's so good, why weren't there more of these? Largely it comes down to speed and commercial value. Motorgliders have never been very popular in the U.S. With long distances and (historically) cheap fuel, the U.S. market has preferred aircraft that can travel those long distances at high speeds. Although the RF-5B is economical, it is significantly slower than the typical U.S. airplane. In general, aircraft need to be certificated to be used for commercial purposes. The RF-5B, while certificated in Europe, is Experimental Exhibition in the U.S. So, it has no commercial value and, depending on how its Operating Limitations are written, might need permission every time you want to leave a prescribed area. N99809 had no such flight limitations--but still can't be used for commercial purposes (e.g., flight instruction or commercial airplane rides). So, the RF-5B is purchased for personal use--because you like it, not because you want to make money by flying it. One advantage of an experimental classification is that it expands modification and maintenance options. From my point of view, here was an aircraft that would be more interesting over time, would be more economical to operate and maintain, and could easily fit in standard hangar. Excellent!

Dave helped me contact other present and former owners to get their feedback. Everyone I talked to uniformly loved the aircraft. If they didn't love the one they owned, they wish they had never sold the one they used to own. The biggest problem I ran into was that the RF-5B was so unique, I couldn't find a local A&P to do a pre-purchase inspection. So, I had to resign to having the A&P who had been doing the work on the aircraft, do an annual inspection. As feared, that turned out to be a somewhat rubber stamp affair. But as luck would have it, nothing was so wrong on the aircraft or so expensive, that it couldn't be replaced or rebuilt.

This may be a fine distinction, but I was not looking for 'cheap flying.' I did want the airplane to be reasonably economical (as I had met a number of pilots over the years who sold their aircraft due to high fixed or operating expenses). I wanted an aircraft I could use into retirement. But, I wanted something that was high quality. I had no interest in 'cutting corners.' The RF-5B fit that criteria.

From FAA documents, it appears that RF-5B N99809 (serial 51060) was built in 1975 in Germany. A physical inspection shows it has a 1974 Sportavia-Limbach SL1700E engine.

It was imported to the U.S. in November of 1975 by Collin Gyenes' father (Charles) and his partner (Phil Paul) of Aerosport in Long Beach, CA.

Early in its life, it was sold every few years. The most recent owners tended to keep it the longest. The last two had a number of airplanes, so N99809 was an occasional distraction. Starting in 2006 it was my sole aircraft, so it has was flown more the subsequent few years than it had been for many years.

Sportavia RF5B Sperber
We get our first look at N99809 as it taxies in for the first time


How to get it home?
What also helped was that Dave was willing, for a reasonable fee, to meet me in Wisconsin. If everything worked out, fly with me to Washington, giving me type-specific training along the way. If need be, he'd stay an extra few days to extend the training. That way, I felt I could get it back home in one piece and assuming my skills were up to it, be able to fly the thing safely.

Sportavia RF5B Sperber
Alex and James taxi out for the demo flight


In late June 2006, Dave and I separately flew to Wisconsin, met up, and drove to the airport to see N99809. I had expected to be able to take a day or two inspecting and flying the glider. In fact, Alex flew in, said he was busy and there was an air show ready to start. I had a little over an hour to make my decision and clear out (with or without an aircraft). Wow. Alex took me for a demo flight. There was a cursory review of the logs. Frankly, I wasn't sure about it all. But I felt that the price was reasonable enough that I could resell it if need be, so I closed the deal. One semi-comforting thing was that Dave felt the glider was in good enough shape to trust it as a ferry pilot to get it back to Washington State.



Sportavia RF5B Sperber
The air show meant we taxied among very different aircraft than you'd usually find on the ramp


Last train out
Quickly we found that we had brought far more personal items than would fit in the cockpit with us. Alex, graciously offered to take our overflow, put it in a box and ship it to us. So, as the air show started to shut down the airport, we were one of the last planes out, heading westward.

Sportavia RF5B Sperber
Soaring, prop feathered on a beautiful January afternoon



One of the questions I was asked the most was, 'What's an RF-5B like to fly?' Before I bought N99809, I talked to every current and former owner I could find to ask the same question. I was surprised how uniformly enthusiastic they were. Not just most. Every single one of them loved the glider. I, too, have found it to be a sweet airplane to fly.

The Best

  • Docile: little happens fast. You do need to stay ahead of it, but lightning-fast reflexes are not required
  • Pleasant: even through turbulence it has a pleasant ride
  • View: the shoulder-to-shoulder view of the scenery is amazing
  • View Forward: is good for a taildragger; no S-turns to taxi
  • Stalls: it's hard to get a break; more like a mush


    The Worst
  • Fuel capacity: 2-2.5 hour legs under power; you can't brag about your bladder capacity
  • Cruise speed: about 82-95mph; a reasonable, but not fast, cross-country cruiser; much like an old Taylorcraft
  • Power: be cautious of high density-altitudes; don't get behind the power curve
  • Cooling: climbing on a hot day takes care
  • Crosswinds: it has reasonable rudder authority but Long wings; stay ahead of it
  • Weather: with wood frame and top opening canopies, it's a fair weather aircraft; cold weather is not a problem
  • Taxiing: be thoughtful about lights and signs


    Sportavia RF5B Sperber
    You'll think about signs more than you ever have before.


    General Comments
    In short, I enjoyed flying this aircraft. Should you ever own one, be prepared for ramp questions and people who just want to get photographed standing next to it. Since there are only about 10 of these flying in the U.S., few people have seen them.

    The view is hard to beat. On the ground. In the air. Even just looking out over the long wings is quite a sight.

    The engine and muffler make the glider surprisingly quiet under power.

    On one hand, just a little pressure on the stick creates movement. So, the glider is responsive. But, it is more pitch sensitive than roll sensitive. Rolling into a 45 degree bank takes both rudder and stick. Those 56' wings are just not going to move the same way a short-winged RV will.

    Taking Off
    I've been in some airplanes where quickly opening the throttle can virtually throw you off the runway. That's not a big concern with the RF-5B. On a hot day, you're more likely to want to apply full power from behind the hold-short line, out onto the runway to give yourself more running room.

    Yet, under anything close to normal conditions, the tail lifts at about 45mph (about stall speed). With gentle backpressure, the glider lifts off in about a 3-point attitude at about 52mph (minimum sink) and climbs reasonably well at 62 mph (best L/D). It's ironic how those same speeds keep cropping up. Under these same conditions, you have a relatively short ground roll (200'-600') and a decent climb (400-500fpm).

    Climbing
    Climbing in a stock RF-5B in hot weather is an art. The glider seems to climb well to about 800-1000', but may climb slowly after that. One trick I found is to use the cruise prop, 2800 rpm, trim for 85-90mph, then add upward trim and add slight forward pressure on the stick to yield about 78-80mph. Rather than 'climb' in a normal sense (big power, upward pitch), you 'elevate.' That is, you seem to have an essentially level pitch (in part because you are applying forward pressure on the stick), the engine is getting good cooling because you have good air speed, but the upward trim causes you to gain altitude. One fellow claimed this technique was used by old air-racer's so they could climb while maintaining maximum speed. Sounds possible.

    Cruise
    Due to the pitch sensitivity and those big wings wanting to catch every updraft, this is not a 'trim and forget it' aircraft. It takes attention and input to keep a constant altitude.

    Rudder
    It's not surprising that with those big wings, this is a 'rudder aircraft.' But it can fool you. Under power, banking into turns takes gentle pressure on the rudder rather than big movement. Once in the turn, reduce rudder pressure. But soaring's slower speeds require somewhat more rudder movement. This seems obvious, but it does mean that flying the same aircraft, making the same maneuver requires different inputs. Flying Cessnas never seemed to require that variation, but I tended to fly them at similar speeds. This is different. In many ways, more engaging.


    Sportavia RF5B Sperber
    Good visibility over the nose, but stay ahead of what's happening

    Landing
    The biggest challenge of any pattern work is the existence of other aircraft. How dare they want to fly at reasonable speeds for themselves?? To the typical fixed wing pilot, the RF-5B can ascend and descend at such slow forward speeds your movement is more like a rotor wing. However, to try to be a good neighbor, I fly downwind at about 80mph, at the end of the runway, drop to idle and never use power again. Lower the gear, check the spoilers, adjust the prop to fine pitch. Fly the base at 70, final at 60…trying to slow to 50 or so, over the fence. The spoilers are a tremendous help for altitude control. If I am in the pattern with a typical Cessna, I can often fly a shorter pattern and keep pace with them (as many powered pilots seem to fly much further than they can glide to the runway).

    Learning to flair at the right height can be interesting. I flew Cessna's for years before the RF5B. When learning to land the RF5B, initially I tried to flare about 4 feet above the runway. Not good. It was hard to stop until I realized that I was flaring at exactly the same visual point that I had in the Cessna with vertical seats and tall legs. So, I had to learn a new sight picture for landing. I eventuually got better, but still had a tendency to flare high.

    On short final, open the spoilers about half way, then just fly through the flare to the ground. Wheel landings are prohibited due to possible prop damage. So, keep the nose up, plant the tailwheel, then let the wings stall - dropping onto the main gear. With skill, it's a little plop. Some days, it's a bigger one than you (I) want to admit.

    Crosswinds
    The wings are too long to slip with one wing low all the way to the runway. So, crab on final. Just above the runway, rotate to be in line with the runway. The spoilers can help you plant the glider before the winds carry you off center. Be ready to move the stick laterally into the wind. Don't over do it. You can overpower the nylon outriggers and drop a wingtip onto the pavement, which won't do much for the wood tip and its finish.


    Sportavia RF5B Sperber
    Soaring, prop feathered, near Ephrata, WA
    Photo by Dave McConeghey

    Soaring
    For soaring, reduce power to idle, adjust the prop to climb position. Advance the throttle just enough to turn off the warning horn. During the next few minutes as you fish for thermals, the engine will start to cool. Once you see the temp actually start to go down, you can shut off the engine at any time. Turn off the ignition switch; leave the Master on if you need radios or transponder. If the Master is on, advance the throttle enough to silence the warning horn. Feather the prop.

    The glider banks easily and well, so it's straightforward to get into and stay in most thermals.

    The motorglider needs a stronger thermal than a lighter, high-performance glider. (This may reflect my limitations more than the aircraft...but I'm claimin' it's what the aircraft needs.) Yet, you can fire up the engine and fly to the coast for lunch. You can go "fishing for thermals" on marginal days when other gliders won't pay for a tow. On really weak days, you can "motor soar." The thermals may not be strong enough by themselves, but you can keep the engine on at lower RPM's, giving you enough boost that you can still fly the weak thermals. Overall, a good trade.

    It's important not to become over-confident about engine restarts. At 2,500' AGL, if I'm not clearly within gliding distance of an airport or friendly field, I restart. The engine has always started easily, but I prefer to be conservative.

    Flying the glider is easy, but there are a number of subtleties to flying the glider well. Enough to keep you engaged and to feel good when you do fly well.

    In a broader sense, it's nice to have the balance of powered flight when you want to go somewhere or take someone for a ride, or soaring for a quiet, different kind of challenge.

    I found the positive qualities of the RF5B outweighed any limitations.