Powerplant for Flybaby. How should I approach this?

[valittu]

I want to build a Bower's Flybaby and I'm back and forth between building from scratch and restoring an existing one. I have two viable options:

A. Scratch building the plane would insure that I'd know every inch of it.

B. Completing a "work in progress" or possible restoration project seems more time efficient in the even I get bored. I'm not sure what my attention span is like yet.

I'm leaning towards option B.

What I thought might be a good idea for me is to either assemble a new engine(Aerovee or 1/2VW) or buy a block and completely rebuild a Corvair or Continental just to familiarize myself with the care and maintenance of a combustion engine. I think I would get more out of building of engine than the airplane. I figure the engine build/rebuild I could be working now while I shop for and evaluate projects found on Barnstormer and other sights.

I have no real timeline because this plane is for futzing in retirement. Am I at a disadvantage in any way securing the powerplant first?

 

[wanttaja]

I want to build a Bower's Flybaby and I'm back and forth between building from scratch and restoring an existing one....What I thought might be a good idea for me is to either assemble a new engine(Aerovee or 1/2VW)...

Neither of those engines are adequate for a Fly Baby. The plane was designed for an A65, so you need something at least equivalent. The half-VW is way low on HP, and the Aerovee needs a very small prop, unsuited for a big, draggy, Fly Baby.

I am aware of one Fly Baby currently with a VW-derived engine; it has a reduction drive and turns a nice big prop. However, this plane has been completed for a year and a half and the reports are they're still trouble-shooting.

There is at least one Corvair-powered Fly Baby operating. Haven't heard any details or seen any in-flight pictures, but the engine should do well.

Ron Wanttaja

 

[valittu]

What power plant would you suggest, Ron? Which is the most efficient for a 220 lb payload?

 

[wanttaja]

What power plant would you suggest, Ron? Which is the most efficient for a 220 lb payload?

Build the airplane light, and a Continental A65 would be sufficient. As you increase the Continentals through the A75, A80, C-85, C-90, and O-200, you're going to get better takeoff and climb performance with little drawback... other than increased purchase cost.

Personally, if I were starting from scratch, I'd go with an O-200. All the other small Continentals have been out of production for 50+ years, but the -200 is still being made.

Yes, they're more expensive. You might even consider trying to pick up a used Rotax 912, instead. I think it would make a darn nice Fly Baby engine.

If cost is the issue, go with an A65. They really aren't that popular any more, and parts (though getting rarer) are still available. They don't have starters, though, so be prepared to hand-prop.

Ron Wanttaja

 

[jesse]

What power plant would you suggest, Ron? Which is the most efficient for a 220 lb payload?

I would go O-200. I have an a75 Flybaby, weigh 160 lbs, and personally think it's annoyingly underpowered. Finding parts for an a65/75 is starting to become a real ***** too.

O-200 is still in production and isn't going anywhere anytime soon.

 

[James331]

Obviously stick the largest engine you can shoehorn in there.

More power!!!

 

[valittu]

I would go O-200. I have an a75 Flybaby, weigh 160 lbs, and personally think it's annoyingly underpowered. Finding parts for an a65/75 is starting to become a real ***** too.

O-200 is still in production and isn't going anywhere anytime soon.

Isn't there a Continential 85/200 conversion that's supposed to have some advantages? I think I read that somewhere.

 

[FormerHangie]

If you're wanting to use a VW powerplant in a single seater, have you considered the Onex?

 

[Henning]

What power plant would you suggest, Ron? Which is the most efficient for a 220 lb payload?

O-200, stay away from any auto kits that don't use a reduction drive, automotive cranks are not designed to withstand the gyroscope forces of a prop, especially if you plan to do any aerobatics. O-200s are available cheap enough, and parts are plentiful even if you want to hot rod it. No worries about finding props or any other developmental issues; proven platform, in current production, made for airplane use with a big old end main journal and bearing cased in such a way to absorb the gyroscopic forces easily.

 

[N801BH]

Obviously stick the largest engine you can shoehorn in there.

More power!!!

Great advice.........

 

[N3368K]

Agree O-200. Plentiful parts. You can always fly at reduced power in cruise and burn A-65 fuel consumption, but still have power for good takeoff and climb performance.

A and C series are good engines with bullet proof lower ends, but parts are becoming harder to source and more expensive.


Jim R
Collierville, TN

N7155H--1946 Piper J-3 Cub
N3368K--1946 Globe GC-1B Swift
N4WJ--1994 Van's RV-4

 

[d.grimm]

I've had some friends build up A-65's with C-85 cylinders lately.
Lots of serviceable parts available for good prices.
One actually got a Field Approval for this mod so that
He could keep his Luscombe an 8A.
Dave

 

[dell30rb]

I would go O-200. I have an a75 Flybaby, weigh 160 lbs, and personally think it's annoyingly underpowered. Finding parts for an a65/75 is starting to become a real ***** too.

O-200 is still in production and isn't going anywhere anytime soon.

Is it because the plane is slow in cruise, or won't climb?

I have maybe 150 hours in a clipped cub with an 85hp continental. It was slow in cruise. The FPM climbing was slow, but it climbed at such a steep angle (because it was so slow) that it actually felt like you were climbing fast. Until you get more than 1000 agl and are trying to hit an altitude.. then it took forever.

 

[Kiddo's Driver]

If you want a Lycoming instead of a Continental you could try an O-233/IO-233, or an O-235. The 233 is lighter.

 

[N3368K]

I've had some friends build up A-65's with C-85 cylinders lately.

Lots of serviceable parts available for good prices.

One actually got a Field Approval for this mod so that

He could keep his Luscombe an 8A.

Dave

Don't you have to machine the case to do that?


Jim R
Collierville, TN

N7155H--1946 Piper J-3 Cub
N3368K--1946 Globe GC-1B Swift
N4WJ--1994 Van's RV-4

 

[Capt. Geoffrey Thorpe]

A runout 150 would give you a core to rebuild yourself plus a lot of fiddly little things that end up costing an arm and a leg to buy new like brake cylinders, instruments, etc.

 

[Henning]

A runout 150 would give you a core to rebuild yourself plus a lot of fiddly little things that end up costing an arm and a leg to buy new like brake cylinders, instruments, etc.

That would be a good plan, better yet, find a corroded out one with a mid time engine.

 

[d.grimm]

Jim,
I was told a very slight bit of machining.
Dave

 

[valittu]

A runout 150 would give you a core to rebuild yourself plus a lot of fiddly little things that end up costing an arm and a leg to buy new like brake cylinders, instruments, etc.

That would be a good plan, better yet, find a corroded out one with a mid time engine.

Are 150 parts interchangeable with a FlyBaby or is it just a generic enough plane?

 

[Capt. Geoffrey Thorpe]

Are 150 parts interchangeable with a FlyBaby or is it just a generic enough plane?

Flybaby parts (like any homebuilt) are the parts that you decide to install as you build - not some "official" list on some type certificate.

Some parts, like wing spars, won't work. But, pretty much everything firewall forward can be bolted on (may have to adjust the engine mount - but if you can weld...). Some parts like brakes, airspeed, throttle / mixture cable (if it's long enough) can be adapted to work nicely. In this case, mainwheels might work if you can find big doughnut tires to fit (Flybaby has no flex in the gear other than the tires). Fuel tanks won't fit, but the selector might. The POS radio from a 150 might be good enough for day VFR...

Pretty much depends on your imagination and your level of cheepassitivity.

 

[jesse]

I really don't think a runout 150 would be worth it. Not much in the 150 would be ideal for a Flybaby.

 

[N801BH]

Flybaby parts (like any homebuilt) are the parts that you decide to install as you build - not some "official" list on some type certificate.

Some parts, like wing spars, won't work. But, pretty much everything firewall forward can be bolted on (may have to adjust the engine mount - but if you can weld...). Some parts like brakes, airspeed, throttle / mixture cable (if it's long enough) can be adapted to work nicely. In this case, mainwheels might work if you can find big doughnut tires to fit (Flybaby has no flex in the gear other than the tires). Fuel tanks won't fit, but the selector might. The POS radio from a 150 might be good enough for day VFR...

Pretty much depends on your imagination and your level of cheepassitivity.

Great word....

 

[3393RP]

Obviously stick the largest engine you can shoehorn in there.

More power!!!

This is true for anything powered by an internal combustion engine. Cars, boats, airplanes, ditch pumps...

Even air raid sirens. Yeah, it's a Hemi.

 

[pigpenracing]

I would hang a M14P on it...

 

[Henning]

Are 150 parts interchangeable with a FlyBaby or is it just a generic enough plane?

Pulleys, cables, instruments, nuts, bolts, and other hardware... all generic. You could likely fill most of your hardware requirements salvaging them off a 150.

 

[jesse]

Pulleys, cables, instruments, nuts, bolts, and other hardware... all generic. You could likely fill most of your hardware requirements salvaging them off a 150.

The vast majority of hardware costs, like probably over 90 percent, on a Flybaby will not be on a Cessna 150. You have like $1400 worth of turnbuckles on a Flybaby that the 150 doesn't have. I spent near a thousand just on the bolts that hold the wing anchors on. A 150 doesn't have those. The desirable wheels and tires for a Flybaby aren't on a 150.

Other than the airspeed, altimeter, and maybe tach, none of the instruments are going to be something you'd want on a Flybaby. Incredibly unlikely much of any of the bolts would be the right length.

Pretty much the firewall forward would be about the only useful stuff, and not all of it, be better off to buy that stuff then buy and entire airplane you're going to have to invest time into parting out, selling, and storing while you do that.

 

[valittu]

The vast majority of hardware costs, like probably over 90 percent, on a Flybaby will not be on a Cessna 150. You have like $1400 worth of turnbuckles on a Flybaby that the 150 doesn't have. I spent near a thousand just on the bolts that hold the wing anchors on. A 150 doesn't have those. The desirable wheels and tires for a Flybaby aren't on a 150.

Other than the airspeed, altimeter, and maybe tach, none of the instruments are going to be something you'd want on a Flybaby. Incredibly unlikely much of any of the bolts would be the right length.

Pretty much the firewall forward would be about the only useful stuff, and not all of it, be better off to buy that stuff then buy and entire airplane you're going to have to invest time into parting out, selling, and storing while you do that.

Jesse, when you were updating or restoring your Flybaby, was there a kit you could buy from Aircraft Spruce, or did you just make an inventory list and shop around for the best deal for parts?

 

[jesse]

Jesse, when you were updating or restoring your Flybaby, was there a kit you could buy from Aircraft Spruce, or did you just make an inventory list and shop around for the best deal for parts?

The plans have part numbers for about everything BUT you have to remember that a Flybaby is very much a "build to fit" airplane. The builder builds many of the parts by measuring what will fit their airplane at that stage in the process versus exactly what the plans say. Things "drift" as they move along.

For example, the length of the wing anchor bolts that were in the plans was definitely not right for my airplane. There are 8 *very long* AN3 bolts that hold the wing anchors on. Those bolts run from through the top anchor plate, through the spar, and then through the bottom anchor plate. The trick is that you don't want too much thread exposed and you can only stack so many washers.

This part was a real PITA. I had to measure each bolt hole and ultimately each of the 8 bolts ended up needing to be different lengths. They were not lengths that were stocked by Spruce or any of the major dealers anymore. AN3 bolts that long are not common on aircraft.

I had to scour the internet, and pay a pretty ridiculous amount for some of them.

Drilling them out to AN4 bolts would have made things easier but I just wasn't really comfortable with the risks of drilling that long of a hole through the spar with the wing already built.

Spruce has a "kit" of what you need but there is no way I would buy that if I were building the thing. It's unlikely that what is in the kit is actually what you would precisely need years later when you're finishing X component of the airplane.

I have a whole wall full of aviation hardware that I stock in my hangar. Tons of different sizes of various nuts, bolts, washers, turnbuckles, nicopress fitting, etc, etc. basically anything you could ever need on a Flybaby. It really sucks to be working on the airplane and have to stop because you don't have the hardware you need.

 

[valittu]

The plans have part numbers for about everything BUT you have to remember that a Flybaby is very much a "build to fit" airplane. The builder builds many of the parts by measuring what will fit their airplane at that stage in the process versus exactly what the plans say. Things "drift" as they move along.

For example, the length of the wing anchor bolts that were in the plans was definitely not right for my airplane. There are 8 *very long* AN3 bolts that hold the wing anchors on. Those bolts run from through the top anchor plate, through the spar, and then through the bottom anchor plate. The trick is that you don't want too much thread exposed and you can only stack so many washers.

This part was a real PITA. I had to measure each bolt hole and ultimately each of the 8 bolts ended up needing to be different lengths. They were not lengths that were stocked by Spruce or any of the major dealers anymore. AN3 bolts that long are not common on aircraft.

I had to scour the internet, and pay a pretty ridiculous amount for some of them.

Drilling them out to AN4 bolts would have made things easier but I just wasn't really comfortable with the risks of drilling that long of a hole through the spar with the wing already built.

Spruce has a "kit" of what you need but there is no way I would buy that if I were building the thing. It's unlikely that what is in the kit is actually what you would precisely need years later when you're finishing X component of the airplane.

I have a whole wall full of aviation hardware that I stock in my hangar. Tons of different sizes of various nuts, bolts, washers, turnbuckles, nicopress fitting, etc, etc. basically anything you could ever need on a Flybaby. It really sucks to be working on the airplane and have to stop because you don't have the hardware you need.

Thanks! Sounds like stocking up like you did will keep me ahead of it's maintenance.

Do you ever plan to rebuild the canopy? Didn't you lose it in a flight or something or am I confusing you with Ron or someone else? Also, do you plan to ever paint it?

 

[jesse]

Thanks! Sounds like stocking up like you did will keep me ahead of it's maintenance.

Do you ever plan to rebuild the canopy? Didn't you lose it in a flight or something or am I confusing you with Ron or someone else? Also, do you plan to ever paint it?

I did not rebuild the canopy, I started, got about 30% of the way, and was flying it during that period open cockpit. I then realized I like it way better open cockpit and left it that way.

I have not painted it. Honestly at this point, I'm probably going to look at selling it when spring comes. It's a good airplane, it needs an owner that will fly it, I don't have the time for it anymore and have plenty of other airplanes to keep flying that generate revenue.

 

[Henning]

Fly baby is a wood plane right? I would think that starting from scratch, with CAD cut panels and structures off digitized tracings being the best cost/time effective way to produce the components now, that one would be pretty safe to to buy the hardware kit to go with the designs.

 

[N801BH]

Fly baby is a wood plane right? I would think that starting from scratch, with CAD cut panels and structures off digitized tracings being the best cost/time effective way to produce the components now, that one would be pretty safe to to buy the hardware kit to go with the designs.

Yeah. I thought the same thing.....

If the plans say use clear fir for the spar and finish it to 2.5", and each bracket is .125" thick.. You would need just under 2.75 shank length bolts...

Ps.. I am just throwing out numbers for examples...

 

[Henning]

Yeah. I thought the same thing.....

If the plans say use clear fir for the spar and finish it to 2.5", and each bracket is .125" thick.. You would need just under 2.75 shank length bolts...

Ps.. I am just throwing out numbers for examples...

When parts, especially precision parts like knees and such were hand cut, I can see where individual craftsmanship can end up with both individual and cumulative effects that cause what Jesse describes, but CAD/CAM production shops have pretty much eliminated that. Yeah, there is a cost to it especially the tracings, but when you figure in wasted materials by a first timer that isn't a ship wright or cabinet maker, you come out about even, not to mention cutting a year or more off your build time.

 

[N801BH]

When parts, especially precision parts like knees and such were hand cut, I can see where individual craftsmanship can end up with both individual and cumulative effects that cause what Jesse describes, but CAD/CAM production shops have pretty much eliminated that. Yeah, there is a cost to it especially the tracings, but when you figure in wasted materials by a first timer that isn't a ship wright or cabinet maker, you come out about even, not to mention cutting a year or more off your build time.

Agreed,,,, But... IIRC, if you get the "sandwich" part assembly off by a little bit, you can stack up to 3 washers to get the correct grip length bolt.

 

[Henning]

Agreed,,,, But... IIRC, if you get the "sandwich" part assembly off by a little bit, you can stack up to 3 washers to get the correct grip length bolt.

I'm not sure why you can't trim the bolt.

 

[N801BH]

I'm not sure why you can't trim the bolt.

In aviation, it is the shank length, not the overall length... Can't trim the shank..

 

[valittu]

I did not rebuild the canopy, I started, got about 30% of the way, and was flying it during that period open cockpit. I then realized I like it way better open cockpit and left it that way.

I have not painted it. Honestly at this point, I'm probably going to look at selling it when spring comes. It's a good airplane, it needs an owner that will fly it, I don't have the time for it anymore and have plenty of other airplanes to keep flying that generate revenue.

Keep me posted on what you decide.