# O-100-- interesting new engine

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#### Victor Bravo

##### Well-Known Member
HBA Supporter
Cool . Lets get one flying .
It has flown numerous times. I was there standing on the runway when it flew the first time, and I was there flying the chase plane a few wingspans away when it flew for video and photos a few months later. Pete's son flew it as well. Pete had made a last-minute change to the lower crankcase and rear accessory case to allow the engine to be used on Rotax style bed mounts, and Continental style "ear" mounts. These changes are certainly not insignificant, but they do not affect the rotating or reciprocating parts of the engine.

#### Yellowhammer

##### Well-Known Member
HBA Supporter
At the moment the April issue of Kitplanes is being finalized (I know this because I have an article in it and I got the final check copy yesterday)... so yes, the news of Pete's passing wouldn't have made it in time for the February issue.

#### EzyBuildWing

##### Well-Known Member
Franklin 117 cubic inch twin-cylinder engine produces 60 HP at 3200 RPM, and weighs 165 lbs dry. Compression ratio 8.5 to 1.
Interestingly, specs show the Duncan single-rotor Mazda-wankel direct-drive produced 60 HP at 4000 rpm with 9.4:1 compression and a 32 mm POSA Super-carb. It weighed 143 lbs including radiators and coolants and oil. 3.5 GPH and 3000hrs TBO. A 48" diameter 4-bladed lightweight carbon-prop could be used.

#### BJC

##### Well-Known Member
HBA Supporter
Franklin 117 cubic inch twin-cylinder engine produces 60 HP at 3200 RPM, and weighs 165 lbs dry. Compression ratio 8.5 to 1.
Interestingly, specs show the Duncan single-rotor Mazda-wankel direct-drive produced 60 HP at 4000 rpm with 9.4:1 compression and a 32 mm POSA Super-carb. It weighed 143 lbs including radiators and coolants and oil. 3.5 GPH and 3000hrs TBO. A 48" diameter 4-bladed lightweight carbon-prop could be used.
What airframe would you use that on?

BJC

#### Victor Bravo

##### Well-Known Member
HBA Supporter
Pete looked at the Franklin and knew about its reputation for harsh low-frequency vibrations. This "informed" the design of the O-100, because he specifically wanted a smooth running engine that would not tear apart wood glue joints and thin wall tubes found in light airplanes. So he designed a counterweight into the crankshaft to reduce that vibration. Worked very well.

#### Protech Racing

##### Well-Known Member
What is the FWF weight? What planes does it fit and fly?

#### Victor Bravo

##### Well-Known Member
HBA Supporter
IIRC the flying prototype was 105 pounds dry, but the last changes to the crankcase and rear accessory case will probably add 2 or 3 to that number.

There are many many different airplanes that could benefit from this engine:

Anything that would have used a 45-60HP Volkswagen derivative, the 503-582 Rotax and similar size 2-stroke engines, anything that would have flown well with that 2 cylinder Franklin, any of the antiques that used the Continental A-40 or A-50, or the E-113 Aeronca engine, probably half of the (short list of) airplanes that successfully used the 55 and 65 HP Lycoming O-145, and perhaps even the smaller/lighter 1/3 of the airplanes that used the Continental A-65.

The 2 seat Cubs, Champs, Luscombes and Taylorcrafts... NO.

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#### BBerson

##### Light Plane Philosopher
HBA Supporter
100 cubic inch is 1640cc. Same power as a 1640cc VW (50 hp at 3600 rpm, less at prop rpm)
The four cylinder Continentals are much larger, of course. This is a half Continental.

#### blane.c

##### Well-Known Member
HBA Supporter
I like the whole concept of the O-100, one thing I am curious of is how it is going to run on one cylinder we all know it is going to happen.

#### Victor Bravo

##### Well-Known Member
HBA Supporter
100 cubic inch is 1640cc. Same power as a 1640cc VW (50 hp at 3600 rpm, less at prop rpm)
The four cylinder Continentals are much larger, of course. This is a half Continental.
Same displacement does not mean same power, otherwise a 1Liter Formula One car would be as fast as a 1Liter Suzuki Sprint. Then there's stroke, torque, compression ratio, etc. that create even more differences.

#### BBerson

##### Light Plane Philosopher
HBA Supporter
Same displacement does mean same power if compression ratio and rpm is same.
(very slight difference in friction)

#### Yellowhammer

##### Well-Known Member
HBA Supporter
100 cubic inch is 1640cc. Same power as a 1640cc VW (50 hp at 3600 rpm, less at prop rpm)
The four cylinder Continentals are much larger, of course. This is a half Continental.

Those engines don't weigh anything close to 104 pounds like the Pegasus. That's what make the Peg such a kick ass power plant.

#### blane.c

##### Well-Known Member
HBA Supporter
RPM and camshaft, isn't the camshaft different in the O-100 as well? Different cam = different torque multiply (in foot lbs) that times RPM and divide by 5252.

If you have a 100hp engine with propeller and you decrease RPM 10% then you have about 75hp. If you can get 10% more RPM instead?

#### galapoola

##### Well-Known Member
I like the whole concept of the O-100, one thing I am curious of is how it is going to run on one cylinder we all know it is going to happen.
I remember watching a mechanic turn off the spark to different plugs on a 4 cylinder with his diagnostic rig. It was easy to do with a computer controlled ignition and fuel injection. Interesting results but not terrible vibration at idle. That was an inline 4 so results would vary. My 20hp opposed 2 Briggs was running fine at max throttle when a crank arm broke. Just lost power and died, no shaking.

#### Protech Racing

It comes down to ; how many here will pay 8000$for the engine? 8000 may well buy a complete 0200. #### blane.c ##### Well-Known Member HBA Supporter O-200 about 190lbs, O-100 maybe 110lbs or so? So somebody willing to give up 40 to 50 horsepower to lose 80lbs. #### berridos ##### Well-Known Member Wish it had direct injection instead of carbs. How much do should the starter and alternator weight to get to the total dry weight? 8000$ is a bargain.
The weight makes it unique for single pilot aircrafts.

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#### Pops

##### Well-Known Member
HBA Supporter
Log Member
O-200 about 190lbs, O-100 maybe 110lbs or so? So somebody willing to give up 40 to 50 horsepower to lose 80lbs.
Hard to get a 0-200 down to 190 lbs. My C-85 with slick mags, stromberg carb, no starter, no generator or alternator. I even replaced the brass crankcase vent elbow with an aluminum one to save several ounces. Made light aluminum block off plates for the starter and gen holes. It weighs 187 lbs. The 0-200 is a few pounds heavier than the C-85 with the vacuum pump drive bose, etc.

#### Protech Racing

##### Well-Known Member
My only conversation with Peter was regarding the EFI system . Pretty easy and about 1000\$ per unit . All of that is covered on the EFI thread .
Getting rid of the expensive and heavy Magneto was another option and lower priority.
The starter and alternator I know nothing about. A couple of flying magnets and coils could provide enough charge to run the EFI bits. IMHO. But I am not an electrical engineer , I consult a good friend that is.

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#### EzyBuildWing

##### Well-Known Member
Ken Wallis Autogyro flew very successfully with a twin-cylinder 165 lb Franklin engine.
If the new 0-100 can can offer similar power for 110 lbs, it should be super-popular with gyro-flyers if price is reasonable.
I notice some gyros are now flying with 36HP Polini Thor engines.
Check out this excellent old Ken Wallis vid here (Ken was the Master):