Advice for Fly Baby Builders and Pilots

This page contains information of use to new or prospective builders or owners of Fly Babies.

 For more in-depth technical information, see the Fly Baby Tech Page.

A Fly Baby Bibliography .  Luis Hernandez made a list of magazine articles featuring the Fly Baby.

Questions?  Email Ron Wanttaja .

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Advice for Builders

Advice for Pilots

Maintenance Issues

Available:  Reprints of The Fly Baby Bulletin

Back in the late '60s, Hayden Ferguson published a newsletter for Fly Baby builders.  Hayden has kindly provided me with a clean copy of all the newsletters, and permission to reprint them.

This are of pretty good interest to Fly Baby builders.  There are a number of hints and suggestions, and a total of 200 pages (printed double-sided, so there are only 100 sheets).  Be advised there is an equal amount of "What Joe Smith is working on now" sort of information...vital and informative when the newsletter is mailed out, but of less use to builders thirty years later.  It's fun to read, though.

Anyway, I ran some copies for the Fly Baby mailing list members, and have about five left.  I'm selling these for $20, US Postage paid. Email me for ordering information.

The Weights of the Parts

Jeff Gray came across this list in a 1963 issue of AIR PROGRESS magazine: Total Empty Weight: 605 lbs.

Thanks, Jeff!

[Oct 2005 update:  After a discussion on the Fly Baby mailing list, two of us went out and weighed our removable turtledecks.  Both weighed 10 pounds]

Flying Advice

I have about 270 total hours of Fly Baby time over the past ten years. There are certainly people with more experience and able to better explain how to fly the airplane, but I'll take a shot at it.

First off, the Fly Baby has "Conventional", or "taildragger" gear. It's well-behaved as a taildragger, but it has all the quirks of the breed. If you've never flown one before, get ten hours of dual in a Citabria or similar aircraft before tackling a Fly Baby.


In both N500F and my current Fly Baby, I couldn't see directly forward while taxiing because the nose blocks the view (I'm six feet tall, but much of that is in my legs). I can lean to one side or the other and see forward above the cylinder shrouds. Most of the time, I just S-turn. Nothing difficult about it, and...well, yes, I think it looks cool. :-)

Taking Off

Takeoffs are straightforward: Align the plane with the centerline, add power, forward stick to lift the tail, then lift off at 55-60 MPH or so.

The Fly Baby tracks pretty straight. However, there is a relatively narrow speed range around 35-40 MPH where it tends to get a little squirrelly. You don't really notice it on a normal takeoff, since you accelerate through the range relatively quickly. However, if you try some "high speed taxiing" before your first flight, you might end up coasting along this range. I do not recommend high speed taxi testing for this reason. Make one run, if you want. But you're taking a lot less risk by just taking off than by holding partial power for a high-speed run.


Perfectly straightforward. Put the top of the gas cap on the horizon for about a 80 MPH climb at 500 FPM or so. The 'Baby will climb faster, but the shallower angle gives better visibility forward.


Again, perfectly straightforward. On my C-85, I cruise at about 2300 RPM and see about 95 MPH. Good visibility all around.

There is one aspect of Fly Baby flight, however, that tends to get some people needlessly worried: The way the landing wires sag (and shake) in flight.

Fly Baby wings are wire-braced, just like a biplane but without the "bi". The landing gear is rigid under the fuselage. The flying wires run from the wheel hubs to the spars, about 60% towards the wingtip. The fitting goes through to the top of the wing, where the landing wires run to the cockpit area. Here, the landing wires attach to a steel strap which goes through a socket in the fuselage to a shelf in front of the instrument panel. A large turnbuckle joins the two straps.

Tightening the big turnbuckle does an overall tightening of the entire wing bracing. As the turnbuckle is tightened, the dihedral increases (slightly, of course) and the flying wires grow tighter.

When the plane is in flight, the weight of the aircraft is supported by the wings. The flying wires (under the wing) go bar-taut. At this stage, the landing wires aren't under any tension at they go slightly slack. They sometimes even "shiver" in the slipstream.

It's no problem at all. You can reach out, grab a handful and shake 'em back and forth. You could even take a bolt-cutter to 'em, and it wouldn't make any difference. In flight, they aren't loaded. I've even tightened the center turnbuckle in flight. They still shake. An "arrow" running between the wires seem to help damp out much of the shaking. I've seen 'Babies with little "stabilizer fins" on the arrow to try get it stable.

However, I should note one possible source of too-slack landing wires: The steel strap they attach to is shaped like a sideways letter "T", with the base of the T going through the socket in the fuselage (See the drawing under "Wing Folding". If the landing wires are too long, the shoulder of the T "bottoms out" on the socket when the turnbuckle is tightened, and the wires never do get tight. This happened on N500F. The solution is to adjust the individual turnbuckles on each landing wire to get the general length of the wires shorter and prevent the T from bottoming out. When you fly, note which wires flap the most, and after you land, slightly tighten their turnbuckles.

Again, it's an aesthetic issue, not a safety one.


Remember, there is no mechanical stall warning on a Fly Baby. You'll tell you're approaching stall by the lowering pitch of the wind in the wires, and a little buffet about 5-10 before.

But when the stall breaks, it breaks abruptly. It's not a gentle Cessna-type stall, but it's not especially vicious, either. The nose drops abruptly to about 20 degrees below the horizon. A wing may drop as well, depending on rig and/or whether you're holding some rudder. It recovers nicely and with standard techniques.

Before you ask: I've never spun one. People who have report no problems.


Two things to remember about landing Fly Babies. First, They don't glide flat. All the drag of the open cockpit, fat tires, and bracing wires brings a relatively steep glide angle. It's about equivalent to the Cessna 150 with fully-deployed 40-degree flaps.

Second, the Fly Baby has no shock absorbing capability other than the tires.

The stiff landing gear is probably the biggest actual problem most new Fly Baby pilots have. The solution, at first, anyway, is to wheel-land for the first ten hours or so. On a wheel landing, approach at a slightly higher speed and try to fly the plane down to "grease" the wheels down. I find the results far better than attempting stall landings.

One mitigating factor: the Fly Baby landing gear is extremely hell-for-stout. N500F had had almost 300 pilots fly it over the past 35 years, and I watched some of them REALLY slam the airplane down.

It's embarrassing, but rarely damaging. It doesn't take long to pick up the knack.

Builder/Owner's Advice

Here's some advice to take heed of during the building process, and/or some things you might want to do if you buy a used Fly Baby.

Landing Gear

The landing gear is a critical element to the wing bracing system. Follow the plans, especially when it comes to the axle tube. This tube is also an element of the wing support...there have been one or two builders who bolted together two tubes instead of using one piece of tubing. Follow the plans.

To understand how Fly Baby wing bracing works, see the Bracing page.


There have also been two builders who used ordinary pliers to swage their Nicopress fittings. They died. Use a swage.

Forward Flying Wires

In the plans, Bowers specifies 1/8" wire for all bracing wires. I recommend going to 5/32" for the forward two flying wires (the wires UNDER the wing) on each side. Going one size larger gets you twice as much strength with trivial weight. They do take larger turnbuckles, though, so watch the wing-attach plates.

If you haven't read it yet, take a look at the information available on the loss of Fly Baby N96MG . I really, REALLY recommend that people use ordinary cable like Pete specifies, and don't "upgrade" their airplanes with streamlined flying wires.

The Spar Carry-Though Modification

There have been some warnings issued regarding the Fly Baby rear-spar carry-though.

The alerts came about when rotting in the Station 5 Bulkhead (the one behind the pilot) allowed the wing to come free in flight. When a plane is in flight, the forces tend to pull the wingtips forward and up. If the aft spar carry-though is allowed to deteriorate, the aft spar pins just pull through the rotted wood and down you go

It should be noted that this failure occurred in an airplane that had sat outside neglected in Florida for years. It underwent only a cursory inspection prior to the fatal flight. The prototype Fly Baby flew over thirty years without this modification.

The reinforcement can be accomplished in either of two ways. If the aircraft is still under construction, two steel straps are attached to the lower carry-through between the two holes for the spar pins. This gets the carry-through out of the equation. Basically, it's just a pair of 1.25" wide .062" piece of 4130 steel running between the holes in the carry-through where the spar pins are inserted.

If the aircraft is already completed, separate diamond-shaped .062" steel plates are bolted on either side of the carry-through at the pin locations. Full details are contained on Pages 9-6 and 9-7 of the Fly Baby Assembly Manual.

It's not a critical mod... assuming you don't have any rot at the carry-though or wing spars. And if you do, I suggest grounding the aircraft immediately in any case.

To check for rot, you'll need a sharp jackknife. The basic procedure is to lightly jab the knife into the wood. If it doesn't hardly penetrate, there's probably no rot. If it goes in easy, it's rotted.

It's a good idea to check this area for rot at every annual. To do the procedure on a Fly Baby, start by removing the wings. Jab the spar butts (one or two is all that's necessary, you don't have to play mumbly-peg) on the wings themselves, and reach into the wing through the access holes in the root rib and check the lower part of the spar. When the wings get a clean bill of health, test the areas outboard of the spar pin holes on the Station 5 carry-through.

Again, most Fly Babies don't need the mod. The reinforcement is mostly for peace of mind.

Service Note on the Tailwheel Steering Horn

The tailwheel is steered by a bellcrank bent out of flat 0.090" steel, as shown in Figure 6-6 of the plans (page 6-11 in my copy).

At about 1700 hours total time, it was discovered that one of the legs of the horn was tearing off right at the bend line. The tear was almost 3/4ths of the way through when discovered.

While the design is similar to the rudder horn, the rudder horn is flat and incorporates a bend at the leading edge to strengthen it. The legs of the Tailwheel Horn bend down at a 45 degree angle and thus can't incorporate a bend.

Our fix on N500F was to weld up the crack and add stiffeners to the legs by welding on small triangular pieces of steel at the leading edge.

If you're flying a completed Fly Baby, keep an eye on this area. If you're building one, go ahead and install a modified horn instead of the stock one.

Aileron Gap Seals

The standard Fly Baby plans have the builder install gap seals on all control surfaces, including the ailerons.

For some reason, many Fly Baby builders seem to leave these off. I've never flown one without seals on the rudder and elevators, but both the Prototype and the one I bought in 1996 didn't have the seals on the ailerons.

The plane definitely flies better with the aileron gap seals in place. Without them, roll seems a lot more sluggish.

If you haven't covered yours yet, install the seals as shown in Figure 7-5 of the plans. If you have covered your plane, fear not: The solution is easy and cheap.

Disconnect the aileron pushrod at the aileron. Get a friend to hold the aileron as far up as it'll go.

Then take a strip of Duct Tape and install it over the gap from underneath.  Here's a drawing::

You can't do it with a single strip of don't want to run the tape over the piano hinges or it'll start trapping dirt that'll make your hinges stiff.  Leave a ~1/8"-1/4" gap either side of each hinge.

That's it! The fabric method generally looks better and last longer, but this isn't half bad. You will have to replace it every two years or so.

Note that the duct tape is applied from underneath, NOT on top!. Yes, I know it's harder, but here's what happened when Drew Fidoe put tape on the top:

I initially had no problems with this but did notice a high pressure zone coming from under the wing, slightly pushing up on the tape. One day while on a short x-country, the high pressure zone unstuck the leading edge of the tape in the centre of the gap seal! I noticed a slight wing heaviness and the tape rapidly opened up so that there was a spoiler across 90% of the aileron. Only the two ends of the tape remained stuck down. This caused a severe wing heavy condition that required nearly full aileron to hold the wing up at cruise speed. All ended safely, but after that, I affixed the gap seal from the bottom side of the aileron wing gap and had no problems. I would not recommend using duct tape on the top of an aileron gap seal for this reason. So put the tape underneath!

For gap seals on the rudder and the elevators, see the Proshold Gap Seals.

Aileron Travel

To combat adverse yaw, the Fly Baby ailerons are differentially geared:  The upgoing aileron goes a lot higher than the downgoing one.  This is accomplished by a combination of the stick linkages and the aileron bellcranks.  Measured at the inboard side, the ailerons are supposed to go about nine and a half inches up, and two or so inches down.

Yes, those numbers are right:  About 9.5" up, 2" down.  It definitely looks a bit funny, 'cause you move the stick to the left and the left aileron seems to go waaaaaay up, but when you move the stick the other way, it barely seems to sink below the level of the wing.  But that's the way it's supposed to be.


Bowers specifies 1/8" plywood on the sides of the fuselage. Use 1/8", don't upgrade to 1/4" for cost reasons. Most of the plywood on the fuselage sides is wasted, really...all that's really needed is, essentially, a gusset around the joints. In fact, some builders rout out the "diagonal" areas between the longerons and the diagonals.

(Photo courtesy of my cyber-bud (and former co-defendant) John Ousterhout)

Going to 1/4" ply adds a lot of completely useless're not even making the airplane any stronger.

Ron's Rants

This section includes a bit of unsolicited advice from a long-time Fly Baby flyer to the Fly Baby builders out there. Most of this is of the "you're gonna want to do it this way, because...." variety. It's advice only; there's nothing hazardous about ignoring material in this section.

Electrical Systems

Oh, man, don't get me started.

You don't need an electrical system in your Fly Baby. Here's why:

Can't shake the electrical habit? All right, then. Here's a schematic of the electrical system of my own Fly Baby.

See also my write-up on the electrical modifications on my Fly Baby.

Turtledecks: The Fly Baby plans show a removable turtledeck section (the turtledeck is the area above the longerons behind the pilot. I've seen some builders simplify their crafts by building a permanent turtledeck.

You want it removable.

Not for any safety reason, or in fact, any reason I can specifically point to.

But the removable turtledeck makes working on the plane a lot, lot easier. Getting in and out is easy. If you have to work from the cockpit, you can rest tools and parts on top of the flat plywood surface. If you're working on the panel, you can sit on the plywood with your feet on the seat.

The removable turtledeck makes maintenance a lot easier. Trust me. Build it per plans.

Turtledeck Door: Pete shows two possible door sizes for the access door in the Turtledeck...a kind of half-door, and a full width door.

When I bought N45848, it had the small door. You can't fit a greasy piglet through the thing. I couldn't even reach all the way back in the turtledeck through the small door.

I enlarged the door. Now, I can dig stuff out from anywhere under the Turtledeck. I can cram a camera bag or overnight bag into the compartment.

Definitely build a removable turtledeck with a full-size door.  Why did Pete show a half-size door as an option?  Because he had at one point anticipated that the turtledeck itself could be disassembled and carried beneath a turtledeck supporting a sliding canopy.

Access Panels: The more access panels you install during the construction process, the easier maintenance is going to be, later.

When N500F, the prototype, was rebuilt in 1982, Cecil Hendricks and the Chapter 26 crew added a foot-wide access panel in the belly. It ran from the bulkhead behind the pilot to the access panel under the rudder pedals. It spanned the section between the two belly stringers, held in place by a bunch of angle nuts tacked to the sides of the stringers.

It made maintenance a lot easier. You can work on the control system and elevator bellcrank from underneath instead of diving in from on top. If you have to work under the panel, you can dangle your feet out the bottom of the airplane (or even stand on the ground) instead of having to fold almost in half.

Speaking of the access panel under the rudder pedals, this one can be somewhat of a beast to take on and off, depending on how you route your brake lines. You have to bend the beast almost in half to get it to clear the landing gear bracing wires.

I converted mine to two-piece... cut a piece of 2" wide aluminum to run down the middle, drill pop-rivet holes on one side and three 3/16" bolt holes on the other. Then cut the panel right down the middle, rivet the strip to the inside of one side, install anchor nuts on the free side, and now you can install the panel in two parts.

Tires: As mentioned earlier, the only shock absorbing capacity of the landing gear is in the tires. Pete designed the Fly Baby to mount 8.00x4 Cub tires, which are fat, low-pressure units with a lot of "give" to them.
Unfortunately, they're getting rare and expensive. Most builders end up using something else.

My  recommendation is a set of 8.00x6s, kept a bit under inflated. I have a set now, and they seem to do quite well. Look right, too. Cost difference between 7.00s and 8.00s is not that big.

Seat:  Most Fly Baby pilots seem to agree:  Pete was having an "off day" when he designed the seat for the Fly Baby.
It has most of the good attributes of a piece of aircraft hardware:  It's light, it's sturdy, it's adjustable, it takes little time to build.

It is also as uncomfortable as all getout. It's two pieces of plywood hinged to each other.  When you're sitting on it, your points of contact are concentrated into one small area on your rear end and one small area on your back.  It's OK for short flights, but it really gets uncomfortable after 45 minutes or so.

 It's not hard to come up with another seat.  On N500F, I built a wood frame for the bottom and curved the upper side rails to a seat design...then bent a piece of aluminum over the top surface.  The back was a U-shaped frame of aluminum tubing, with thin sheet straps across it like a lawn chair.  For Moonraker, I bought a fiberglass chair at the local surplus store for $5.  The seat part unbolted cleanly from the legs, and I just built a frame to match.

It's not something that has to be done before the first flight.  But I think you'll want to eventually count on another seat.

May 2003:  Jeff Gray send me a write-up and photos of the custom seat he built for his Fly Baby.  Looks like a good option....

Candian Builders

This information came from Paul Bowyer of Peterborough, Ontario:
By the way, you may be interested to know that in Canada, a Flybaby may be flown with an Ultralight Pilot Permit as it meets Canadian weight and stall speed requirements of an advanced ultralight . The aircraft need not be re-registered out of the amateur-built category. I do not recommend however, that an ultralight pilot attempt to fly one unless they have been trained on a "hotter" taildragger design of ultralight and are familiar with carb heat/mixture controls etc.

Anyone wishing to do this in Canada must first apply to Transport Canada to have a modification to the C of R flight restrictions. If you are equipped with a higher horsepower engine, it may not fit the rule. Transport Canada will run your specs through the "chicken guts" formula and see what comes out. If anyone is interested I would be happy to walk them through the process and give them the contact names in Transport Canada in the Toronto region.

The Dribbles

No, it's NOT the name of a 1960s rock group.  It's Fly Baby pilot's slang for an odd condition that sometimes occurs when taxiing.

Between a combination of tailwheel spring stiffness, tire condition, tire inflation, temperature, and taxi speed, the airplane sometimes starts bouncing up and down on its tires as it taxies along.  It's not dangerous, it doesn't affect control.  It's just an odd boing-boing-boing as you taxi merrily along.  It's like someone dribbling a basketball.

It is totally harmless.  I've never had it happen during takeoff run or landing roll.  It tends to occur when the tires are tires, freshly-inflated, and especially in colder weather.  If you get the "dribbles", just slow down or speed'll go away.

A Fly Baby Bibliography

Luis Hernandez went through a LOT of work and put together this list of magazine articles featuring the Fly Baby.

Sport Aviation

Dec     1962  Bowers Fly Baby
Apr     1963  Fly Baby (Mods. 0-290G)
July    1963  Fly Baby
Aug     1963  Fly Baby on Floats (Part 1)
Sep     1963  Fly Baby on Floats (Part 2)
Dec     1969  Fly Baby Biplane
Aug     1970   Cross Country in the Biplane
Sep     1970   The Lash Fly Baby
Dec     1971   Fly Baby with Luscombe Wings
Mar     1972   Future Birdman Starts Young at Plane Building
Jul     1972   Two-Place Fly Baby (Side-by-side)
Sep     1972   Fly Baby and Aerobatics by Peter Bowers
Dec     1972   The Inside Story of a Fly Baby Project
Feb     1975   Boyhood Dream
Aug     1975   George Rotter's Fly Baby
Aug     1976   The Pink Baroness
Sep     1976   The Flight of Mr. Gator
May     1980    Fly Baby (Bird)
Jan     1983   Mounds of Joy
Aug     1986   Low and Slow to Oshkosh We Go (Part 1)
Sep     1986   Low and Slow to Oshkosh We Go (Part 2)
Jan     1988   Fly Baby.... The Silver Anniversary
Aug     1991   Fly Baby Structural Failure
Oct     1991   Fly Baby Reinforcement Strap
Dec     1992   30 Years Ago.... 1962 Cover Story


Jun     1986 (pg. 32)  Bowers Fly Baby
Jan     1988 (pg. 30)
Jun     1988 (pg. 22)  Arnie's Legacy (Fly Baby Biplane)
Feb     1989 (pg. 12)  Fly a "Nouvelle Classique"
Aug     1989 (pg. 72)
Apr     1991 (pg. 22)
Apr     1998 (pg. 74)  Make Mine A Fly Baby

The Experimenter

Aug     1998  Fly Baby Structural Failures

Note that if you are an EAA member, you can order reprints of Sport Aviation and Experimenter articles....

Problem with Plans Templates

Photocopiers tend to distort the images the copy...generally making them slightly smaller or larger than the original.

Over the years, the "full size" templates in the plans have suffered from this effect.  Pete always included the dimensions on the template, so before you use the template, measure it to make sure it's the right size.  If not, you can either re-draw it yourself (most are pretty basic) or check and see if it's on one of the CAD templates generated by other Fly Baby builders. 

You can find them on the Templates page.

Note that the Rib templates are especially effected by this copier distortion!   Fortunately, that's one of the templates available.

There's another file that has templates for all the steel parts.