# O-100-- interesting new engine

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##### Well-Known Member
Supporting Member
The Currie Wots pre-war were built light and powered by 37 hp JAP flat twins and some recently discovered cine film of a post-war example with that engine demonstrated a remarkable performance. Harald Penrose flew his 'Airymouse' with that motor for several years before it was equipped with a bigger engine. Most commonly these use an A-65 or Walter Mikron.

But one small biplane which would be an ideal subject for the Pegasus, as VB states, is the Flitzer and the smallest and potentially lightest of the family is the Goblin. I attach a recent GA of a projected example, parts of which have been stored for many years, to be fitted with an existing Z-1M Meteor tailplane, ply-skinned and strut-braced from below to accommodate the all-flying rudder. The tailplane would actually be cantilever, but braced to protect it from damage by hangar gorillas due to the relatively small mounting bolt footprint of the Flitzer stab. Intended motor is an a1834cc VW at the stage. Two others are under construction for a big-bore VW and a Verner 5S.
View attachment 120468
Hello Flitzerpilot,

Yes I nearly built a Flitzer years ago, but life got in the way and I went in other directions as I am not a wood worker. Anyhow, VB has prodded me off an on recently about a Tube and Gusset version of the Goblin similar to a Baslee or Graham Lee version. I sell plans for the Lil Bitts biplane and the rough wing structure could all be done similarly. I have an Avid CNC router on order for project such as this but sadly it wont arrive until April. Avid is crazy busy right now. In the meantime I am setting up the hangar to be ready once everything arrives. Also have a Series 3 Tormach PC1100 waiting to be set up.

#### flitzerpilot

##### Well-Known Member
Hi Addict! Do you have Flitzer plans or more partcuarly Goblin plans? If not, I can send you the latter to your personal email address, gratis.

There are a couple of changes to the plans, one of which is the elevation of the upper rudder hinge position to better accommodate side loading forces. Also there is a simplified single spar tailplane variation - not associated with the recent Meteor tail adaptation. It's all adaptable to aluminium tube fabrication. Kind regards, Lynn

#### Victor Bravo

##### Well-Known Member
Supporting Member
Fear not Lynn, I have a set of original Z-21 plans (that I purchased from Matthew on this site), and the very first second that addicted2climbing wants to build one, or work with you on a tube/gusset version... I will burst through the door of his hangar and the plans will be in his hands.

I understand that the Goblin is not exactly the same as the stock Z-21, but seeing the Z-21 plans will certainly set the hook rather firmly in his gills

#### flitzerpilot

##### Well-Known Member
Salute to you, VB! Yes the Goblin is only of 16'10" wingspan with a length of about 13', depending on engine choice, so it's a minimalist Flitzer and the baby of the family I am still cogitating on how to proceed with the tailplane options. The Meteor tail I have is rather heavy in Douglas fir and will be heavier still if ply-skinned to 'cantilever it'. I do have the Flitzer-Laird LC-1W tail group (see my avatar icon) completed with hinges and horns and I just had a thought today that I could use the Laird elevator at 14" chord and build a light weight semi-cantilever tailplane to match, possibly at 13" chord which would restore the preferred tail arm. The Laird tail tapers in thickness span-wise, to the tips, so the 'new' Goblin stab would also taper to match, but would otherwise be very similar to the original Goblin stab in planform and with the same span. This could be a particularly elegant solution, especially as I have taken pains to make the rudder as light as possible.

I did not want to spoil the ship by having to extend the engine mount to cope with a heavy tailplane.

##### Well-Known Member
Supporting Member
Hi Addict! Do you have Flitzer plans or more partcuarly Goblin plans? If not, I can send you the latter to your personal email address, gratis.

There are a couple of changes to the plans, one of which is the elevation of the upper rudder hinge position to better accommodate side loading forces. Also there is a simplified single spar tailplane variation - not associated with the recent Meteor tail adaptation. It's all adaptable to aluminium tube fabrication. Kind regards, Lynn
Hello Flitzerpilot,

Sorry about my delayed response. I got a call mid day yesterday saying my kid was sick and come pick him up at daycare so only worked half the day. Anyhow thank you so much for your gracious offer and I will send you a PM now with my contact info.

Take care,

Marc

#### flitzerpilot

Hi Marc,

Best,

Lynn

##### Well-Known Member
Supporting Member
Hi Marc,

Best,

Lynn
Thanks I just replied
yes he just had the stomach flu. Hit the entire daycare and nearly all the kids got it.. Better than C19 though so no big deal.

#### Mike von S.

##### Well-Known Member
Supporting Member
The Currie Wots pre-war were built light and powered by 37 hp JAP flat twins and some recently discovered cine film of a post-war example with that engine demonstrated a remarkable performance. Harald Penrose flew his 'Airymouse' with that motor for several years before it was equipped with a bigger engine. Most commonly these use an A-65 or Walter Mikron.

But one small biplane which would be an ideal subject for the Pegasus, as VB states, is the Flitzer and the smallest and potentially lightest of the family is the Goblin. I attach a recent GA of a projected example, parts of which have been stored for many years, to be fitted with an existing Z-1M Meteor tailplane, ply-skinned and strut-braced from below to accommodate the all-flying rudder. The tailplane would actually be cantilever, but braced to protect it from damage by hangar gorillas due to the relatively small mounting bolt footprint of the Flitzer stab. Intended motor is an a1834cc VW at the stage. Two others are under construction for a big-bore VW and a Verner 5S.
View attachment 120468
As Lynn of course knows, I am the American builder of a Flitzer Goblin, currently slated for a flywheel-forward 2110 VW. However, my preference (indeed, my plan) was to mount the DP-100. I spoke to Pete about this several times, including just a few weeks before he passed. Sad. I would love to see his little, flat four-stroke resuscitated.

#### Hot Wings

##### Grumpy Cynic
Supporting Member

@ VB .... or anyone that might have recent news:
Any new developments?

##### Well-Known Member
Supporting Member

@ VB .... or anyone that might have recent news:
Any new developments?
Hello Hot Wings,

I have a bit of news. I recently picked up all the parts for the O-100 from Pete's son Nick. He needed it out of the storage facility and I am hoping to help the family by trying to get this engine finalized in honor of Pete who was my friend. I have no idea whether this will end up succeeding and becoming a saleable product or not but for the time being, I will be working on the design trying to sort out where Pete left off and see where it goes from there. I have a fair amount of cases but unsure if they are the latest revision or not. Also have some of the newer forged cranks but they still need the oil tube installed. I also have all the Solidowrks CAD files. I had also helped Pete with some of the CAD work so I have a fair amount of knowledge of where he was when he passed away. I had also met with him 3 weeks before passing and he gave me an update on what remained then as well.

I picked all this up then immediately left the country to visit my wife's family in France for a bit of an extended trip. We return 11/02 and once back my plan is to inventory what I have and go from there. For the moment this is about as much info as I have. Also since I am just stepping in where Pete left off please dont bombard me with emails requesting refunds or asking where your engine or deposit is. I am not involved in that at all so unable to help there.

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#### Regdor

##### Well-Known Member
Supporting Member
This Turkey is a one winger, it will only fly in a never ending circle....A 50, 60, 70 hp Two Cylinder, Four stroke engine will NEVER not shake your airframe and eye balls loose, Without a very heavy
flywheel or some equivalent lash up, Period.....If you can fly on 50 Hp and 135 lbs,and have only a meager $5K to spend to get your behind in the air, use a bare knuckles VW...... #### Dan Thomas ##### Well-Known Member This Turkey is a one winger, it will only fly in a never ending circle....A 50, 60, 70 hp Two Cylinder, Four stroke engine will NEVER not shake your airframe and eye balls loose, Without a very heavy flywheel or some equivalent lash up, Period.....If you can fly on 50 Hp and 135 lbs,and have only a meager$ 5K to spend to get your behind in the air, use a bare knuckles VW......
Franklin produced two models of two-cylinder opposed engines in the 1930s and '40s, the O-110 and O-120, producing from 45 to 60 HP, and they powered a number of production airplanes. In 1971 Bellanca built 71 7ACA's (a resurrected Aeronca Champ) and powered them with the Franklin 120, which I believe was built in Poland at the time.

So no, it's not something new and shaky. Been done before.

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#### rv7charlie

##### Well-Known Member
Supporting Member
Ten years and 1272 1273 posts. At this point, I'm pretty sure that the Pegasus is the original electric diesel turbine powerplant for small aircraft.

#### TFF

##### Well-Known Member
There is always a design that one engine is too small and one is too big or the torque curve is wrong for its size. O-100 is a gap filler. More than a 1/2 VW and a different power curve than a full VW. A plane heavier than a Legal Eagle but not as heavy as a Baby Ace. It would be cool. It’s not a choice of have to, but want to.

#### Hot Wings

##### Grumpy Cynic
Supporting Member
A 50, 60, 70 hp Two Cylinder, Four stroke engine will NEVER not shake your airframe and eye balls loose
That is your OPINION. Kind of depends on how loose your eyeballs are.
An offset opposed twin can be balanced. Notice anything strange on the prop hub of the Franklin above?
Pete understood this and is part of the reason there is a custom crankshaft and rods.

#### Victor Bravo

##### Well-Known Member
Supporting Member
This Turkey is a one winger, it will only fly in a never ending circle....A 50, 60, 70 hp Two Cylinder, Four stroke engine will NEVER not shake your airframe and eye balls loose, Without a very heavy
flywheel or some equivalent lash up, Period.....If you can fly on 50 Hp and 135 lbs,and have only a meager $5K to spend to get your behind in the air, use a bare knuckles VW...... Anybody who was there, and laid their hands personally on the O-100 while it was running, and who can personally attest to the idea that Pete had balanced it correctly and it was as smooth as an O-200... please take one step forward and feel free to discuss the vibration level. Anybody else who cannot attest to anything about this engine, but just assumes this engine would vibrate wildly.... please take one step back, proceed to the Duct Tape Table, and use a piece of the tape to cover the opening under your nose. There are probably several others, but myself, HBA members MM4440, Topaz, and addicted2climbing have put their hand on this engine while it was running at cruise power, and we can all attest that Pete did in fact design a counterweight or two into the crankshaft, and this counterweight did in fact resolve the typical 2 cylinder engine shake that the Franklin and half-VW are known for. I have zero formal education or experience with these dynamics and forces, but I know for a fact that some-how, some-way... Pete did manage to design that thrash out of this engine. It was a small amount of extra balance weight in the crank, not a ten pound flywheel. The fact that someone has stepped up to at least try and rescue this engine from fading away into a footnote should make everyone pretty happy. #### mm4440 ##### Well-Known Member Supporting Member I have seen and had hands on running O-100 prototypes and was pleasantly surprised at how low the vibration level was. Pete did a great job. #### addicted2climbing ##### Well-Known Member Supporting Member This Turkey is a one winger, it will only fly in a never ending circle....A 50, 60, 70 hp Two Cylinder, Four stroke engine will NEVER not shake your airframe and eye balls loose, Without a very heavy flywheel or some equivalent lash up, Period.....If you can fly on 50 Hp and 135 lbs,and have only a meager$ 5K to spend to get your behind in the air, use a bare knuckles VW......
This is a bold and very incorrect statement from someone who has no knowledge of how this engine was designed or without seeing one one in person. As mentioned by others this engine is quite smooth and the Pete got the Balance right. Pete was a whiz at math and figured out the balance the hard way with pen and paper and then had someone check it with software and the results were a near match. When I met Pete 3 weeks before he passed away he was working on tooling to pour lead into pockets in the crank. I was not a fan of this idea as melting and pouring lead is not safest choice of materials to work with. Also I was worried about the lead creeping over time. I suggested Mallory Discs since they can be bought in various sizes to hit certain weights. This is likely one of the things I will change. Unsure if it will be cost effective but at least its a stable material and not toxic to work with. Brass may be a cheaper option if there is enough room for it to hit the same mass

The remaining items to tackle is the exhaust and induction system. Also need a custom oil sump. Settle on a Carb or possibly an EFI with electronic ignition from RV6ejguy but unsure if adding that complexity is worth it. I have lots to do before then so will cross this bridge when I get there.

#### David L. Downey

##### Curmudgeon under refinement
Supporting Member
This is a bold and very incorrect statement from someone who has no knowledge of how this engine was designed or without seeing one one in person. As mentioned by others this engine is quite smooth and the Pete got the Balance right. Pete was a whiz at math and figured out the balance the hard way with pen and paper and then had someone check it with software and the results were a near match. When I met Pete 3 weeks before he passed away he was working on tooling to pour lead into pockets in the crank. I was not a fan of this idea as melting and pouring lead is not safest choice of materials to work with. Also I was worried about the lead creeping over time. I suggested Mallory Discs since they can be bought in various sizes to hit certain weights. This is likely one of the things I will change. Unsure if it will be cost effective but at least its a stable material and not toxic to work with. Brass may be a cheaper option if there is enough room for it to hit the same mass

The remaining items to tackle is the exhaust and induction system. Also need a custom oil sump. Settle on a Carb or possibly an EFI with electronic ignition from RV6ejguy but unsure if adding that complexity is worth it. I have lots to do before then so will cross this bridge when I get there.
off topic, but... any idea what happened to the Crackerjack development that Pete was working on at the time of his passing?