GlaStar Cruise

John Lake cruising in his GlaStar N484VM
John Lake cruising in his GlaStar N484VM

One of the best things about the GlaStar is going somewhere; a little stick pressure is all it takes. It’s comfortable – get lumbar support for the seat. It has great visibility – if you’re high enough in the seat. You have lots of room – make storage places for the normally carried odd and ends. It carries about anything you can put in it – just stay inside the limits. (The empty-weight, forward CG normally allows for a huge pile of stuff in the baggage area at gross weight.) And the GlaStar flies pretty well hands-off – if you take the time to set the ground adjustable tabs.

The GlaStar Owner’s Manual, section 4-9, 10 and 11, (pages 26-28) gives the reader a good foundation for setting up the GlaStar for cruise. The quickest way I’ve found to get to cruise speed is to maintain climb power, as I trim for level flight until cruise speed is reached. Otherwise, it is not unusual for the GlaStar to remain 5 knots or more below normal cruise speed (particularly at heavier gross weights). Sufficient extra power must be held long enough to get the GlaStar up to maximum cruise speed, then reduce power to normal cruise. Another trick is to climb 300′ above the planned cruise altitude, set cruise power and trim gently downward to pick up some extra speed before arriving at and retrimming for level flight. One way to check whether you’re flying at maximum cruise speed (while in level flight) is to leave cruise power on while trimming slightly down and watch what happens. If your GlaStar starts a gentle descent and then starts flying level again at a faster airspeed, you just gained a few knots for cruise. While a lighter GlaStar will obtain maximum cruise speed and remain there during the flight, a real heavy GlaStar will require a lot of power to get to the higher cruise speeds and then may have trouble staying there in turbulence.


Most of us learned to fly in lighter aircraft, which flew pretty well on 55% power. (They had so much drag a lot of power made little difference in airspeed.) The GlaStar “loves” power and that’s a major reason for its speed. More than once I’ve flown a “slow” GlaStar and found out that coming up to 75% power tended to bring the cruise speed in line with the book values. Other major factors contributing to higher cruise speed are cleanliness of the airframe, (2-5 knots), light to heavy weight, (5+ knots) and additional drag items. It should, with its clean, low drag profile, cruise at the book speeds if you use the same power. The first 400 hours of the prototype GlaStar were flown using a 125 HP, IO-240 with a fixed, cruise prop. At 75% power, we were using around 94 HP and having a blast. The cruise speed of the trike with wheel pants was 130 knots light and 125 heavy. With the installation of the 160 HP engine, cruise instantly jumped to 140 knots light and 135 knots heavy.

You can adjust many things to get the GlaStar to fly straight and level and fast. Everything from wing or tail incidence, rear wing airfoil “canned in,” aileron “fly-up,” flaps adjusted properly, extra drag features installed (no wheel pants, etc.), ground adjustable tabs set and on and on. Most GlaStars are reporting an unusual consistency with equal airframe type, horsepower, thrust (prop efficiency) and weight. We recently flew the new demo, 160hp GlaStar, wing to wing with a 180hp, similar type GlaStar, and found at the same power settings (25 squared) the 180hp was cruising 5 knots faster. This is exactly what the book says. (What the book didn’t say was that the 180hp appears to use about three to four gallons more an hour to get that increase in speed.) Finally, for those GlaStars without autopilot or wing levelers, I carry a couple of large, thick rubber bands tied end to end. Hooked between the stick and throttle or door, this – along with elevator trim – gives me infinite lateral trim adjustment for a totally hands off airplane in smooth air.

Tim Johnson’s articles are his own perspective and reflect over 1,000 hours of safely flying the prototype GlaStar in demonstration, cross-country, and air-show flights. Your experience, training, GlaStar airplane, and local situations may require different procedures. Be safe! Never attempt something just because someone else did it! The current GlaStar Owner’s Manual and current FAA and/or local regulations are your overriding guides. Airspeeds used are KIAS (indicated airspeed in knots).

Previous articleRiveting Tips
Next articleFitting the Glasair Cowling Before the Prop is Installed


  1. New to the Glastar world. In November, brought to Central Texas, Lou Bello’s 2006 Glastar with a TMX O-360 and AC constant speed prop. Didn’t get to fly much during Dec, Jan, Feb, but starting to get in the air regularly. Want to use this wonderful machine to go places, and have been experimenting with various power settings at various altitudes. Wondering what power settings folks are using at 4,000′ to 8000 ‘ cruise altitudes. I’ve used 24/24, 23/23, and 22/22 and haven’t found a “sweet spot” yet for best speed with best fuel burn. Any body got any words to help.

  2. I’m in the camp that believes in leaving the throttle as wide open as possible for most undisturbed airflow through the intake. So after takeoff I usually pull back to 25″ and leave it there. I’ll pull the prop back to 23 or 24 and moderate fuel flow with mixture as best I can. That said, I always plan for legs well within fuel range so I’m rarely flying for best economy. I fly for go-fast.

  3. I flew cross country which gave a lot variations. I sum it up as: 150 to 200 rpm below manifold pressure does well at most any MP setting. Usually 200 below. This is “over square”. I can feel the engine in its sweet spot. Less vibration, engine sounds better. If I set rpm too far below MP, I can feel the engine strain. If cruising at 5000′ I might be around 24 IN and 2200 rpm for good fuel and speed. For 8000′ 25 IN and 2300 rpm. At altitude, you will be at full throttle and manifold pressure will be way lower than what you are used to. Just firewall it (not quite, don’t activate the accelerator pump). If just flying around the potato field for time in the air, then 22-23 IN and 150 rpm below. Almost never cruise square. It is like not using overdrive. A good thing to look at is a Lycoming performance curve chart. It will show the manifold pressure for 75% power (and 65%) at any altitude, and a range of rpm’s. For take off, retract flaps, reduce MP to 25, rpm 2500 for a minute or 2000 FT AGL then throttle back for normal climb square or under square, 24IN and 24-2500 rpm.