Hand Made Bentley BR2 Rotary Engine

[jradetzky]

does it fly?

[TheRealFobican]

LOL the author has a common error´s name! XD

[crash25016]

never saw a rotary engine with the cylinders rotate with the prop... how dosnt the oil force its way into the combustion chamber?

[justforever96]

@crash25016 You're thinking "radial"; all rotaries (not Wankels) do this. A radial is a crankcase/cyls bolted down, with a crankshaft spinning inside, connected to the prop. A rotary is a crankshaft bolted down, with the case/cyls rotating around it, the prop bolted to the case. In terms of valve-train and pistons, they're the same, only reversed. The oil is mixed with the fuel like a 2-stroke; fuel/oil/air drawn thru the crnkshaft/case, into tubes to the valves; it's all burned up: "total loss"

[Poopingbotham]

Very good indeed.  If you can build some full size ones, you wouldn't have much problem selling them, what with so many WW1 replica aircraft flying with non-authentic looking engines.

[yashypandya]

i am with you

[MartinOhrndorf]

Your engine is amazing, congratulations!

[crazystufffff]

dosent this give a massive gyroscopic effect?

[d9a5w3n76]

would it make it to engine swap in a car?

[Fabianp1960]

Thanx,it was hard to figure it out by just looking,and couldn't find on the net any explanation or a more into detail of this particular engine.

[faboledesma]

I never understood why the whole head is turning. ?

[Fabianp1960]

Question,how does the fuel get into the combustion chamber,since the whole engine rotates,don't see how it gets there...

[KarriKoivusalo]

@Fabianp1960

The carburetor is stationary, the fuel mixture is fed through the crankshaft into either the crank case and through a valve in the piston dome (like in gnome monosoupape) or a plenum with headers and through a more normal intake valve like here.

[NMoulana]

hold on why couldnt you just make the engine stationary?

[badbenjy]

@NMoulana the engine was rotated for cooling purposes...

[NMoulana]

@badbenjy well what about that big ass fan right in front of it, wasn't that enough? The rotation must greatly decrease the efficiency of the engine, thats simple physics.

[submanup]

nice work!!!  five stars!

[myConscious]

QUESTIONS:

1. Does the cylinders & the propeller both rotate in the same direction?

2. If they do, what if, the cylinder portion of the engine & the prop were very close to equal in weight and they rotated in OPPOSITE DIRECTIONS to each other, would that not reduce (cancel out the opposing forces) the undesirable "one sided" gyroscopic effect?

Thanks

[Error4O1]

@myConscious The prop is bolted to the casing and cylinders and rotate together. Making a transmission to get the prop to go opposite the cylinders would add weight and complexity, and thus introducing more potential failure points as well as offsetting any benefit by reducing power to weight ratio.

The first thing you have to remember is this design was from the early 1900's, And secondly, it had pretty much reached it's pinnacle in design by the end of WWI (1918-ish)

[GREEVES246]

@Error4O1 there very complex i have a the drawings for it if you made it it must be a

labour of love

have you ever seen the way they used to start these things ! funny thing they have a ford model T and retro fit a shaft with drive from the back axle with 2 spades to engauge the prop and there were mag settings to ajust the throttle !

[Error4O1]

@GREEVES246 Wasn't my engine. I was just a spectator at the event. cfmeq (YT user) was the builder of this engine, and credit has to go to him for the work done.

Yeah, that old-school tech was kind of scary sometimes (I guess it was pre OSHA). I do fly R/C, and sometimes you have to start the models old school too.

[schlusselmensch]

@GREEVES246 That was known as a Huck Starter, by the way.

[quorneng]

@myConscious

The contemporary German Seimens-Halske Sh111 engine did indeed do as you suggest. The cylinders and crank were geared together so they each turned at 900 rpm in opposite directions.

Initially of 160hp, later versions reached 240hp but the low rotational speed of the cylinders tended to cause overheating and poor reliability.

[superfunnyman123]

wow!

[robotpredator8]

its nice, can u show me the rotary engine structure?

[30GB]

i bet its weak engine at high rpms because of gravitational force only good when compressing the air/gas mix and exhaust

[paullubliner]

I take it the headline here should read "Hand Machined"  as opposed it's construction having been done with hacksaw and files.

[ProfessorK100]

that's amazing work! good job.

[whar29]

The torque effect of a spinning mass was pronounced, the vertical tailfin on airframes was set off at an angle to reduce some of the effect at a given airspeed, not moveable in flight so not effective over the speed range. Turns were easier going with the torque .Lubrication was by the total loss method, gallons of castor oil spewing out over airframe and pilot, hence the scarf to wipe oiled goggles !

[trossachs2003]

Ah yes, I remember all this from the Biggles books I read as a kid

[piercebm]

not to mention that caster oil is also a laxitive. so they had to cover up their face with the scarf to filter the air that they breathed.

[whar29]

Radial the cylinders are fixed the crankshaft rotates.

Rotary the cylinders rotate around a fixed shaft. The fuel is ingested into the crankcase, as the piston decends a flapper valve in the piston head opens to allow fuel into the cylinder, closes on the upstroke due to pressure, a system of cams on the fixed shaft work on a pushrod to open exhaust after ignition. Rotary engines were controlled by a "blip" switch. Radial and Rotary are different types of engine.

[mercsport]

It's a small point only, but both of the BR2's valves were conventionally push rod operated, and not the the 'flapper' type you stated.

[paullubliner]

YET Le Rhones were converted into conventional radials immediately following the war, oddly yielding great power.

[gravyguy1]

It looks more like a radial engine rather than a rotary engine.

[popcatzoo]

its a rotary engine because the engine block rotates. he never said it was a wankel engine.

[gravyguy1]

Touche`

[gravyguy1]

That was me talking about something I thought I knew. I never said it was a wankel engine either.

[stopglobalswarming]

This type of engine (radial rotary) was used once in a bicycle wheel, to power bicycles. The fuel tank was encased in the narrow wheel as well. It didn't sell for too long. Perhaps a fuel leak set one on fire.

[trossachs2003]

I'd like to see some stills of the manufacturing stages.

How do you get the fuel to the cylinder heads?

[friedmeat]

in through the crankshaft from behind and then up under pistons through a poppet valve in top of piston

[GavinS1965]

I thought that was a radial engine..

[sixmagpies]

It is....it's a 'rotary radial' where the crank is fixed and the prop spins with the rest of the engine, Many problems in this design such as gyroscopic forces, no way of having an exhaust and having to run the H.T. through slip rings. Radials became ubiquitous as a result.

[GavinS1965]

Aha! I always thought it was dead smart in a curious way,but it seems to me alot of the thrust from the prop would be blocked by the engine,also balancing must have been a nightmare!

[shloop4]

yeah, ive heard that the planes would often drift to one side more than the other because of the engine spinning. maybe if yuo had two on the wings spinning opositly that would fix the problem...

[nh3we]

how does the cylinders get gas?

[nawitus]

Through the hollow crankshaft I guess

[WankelKim]

The description fooled me.

Very cool none the less, respect.

[chopperdanny13]

Beautifully made engine. To those that still dont' get it, it is a Rotary engine with the cylinders arranged Radially around the crankshaft. The crankshaft is fixed to the rest of the fuselage, or test stand in this case, while the engine, connected directly to the propeller, spins around it. One of the main problems was that there was no way to control the throttle. The engine ran either full on or full off, with pilots shutting off the magnetos to regulate rpm. More next comment.

[chopperdanny13]

Another problem with this type, as alluded to and causing the ultimate demise of this type of engine is gyroscopic precession. Planes with these could turn faster one way than the other.  If a pilot stalled, often a violent spin would result. With so much rotating mass changing directions was difficult. Google gyroscopic precession to learn more.

[Error4O1]

Well put. Thanks for commenting.

[trossachs2003]

Biggles used to put this to good effect - the Sopwith camel could perform very fast turns in one direction as a result of this. But it had advantages as well. The engine was its own flywheel so need for a separate flywheel hence less mass. Also the crankshaft was fixed therefore the pistons didn't actually reciprocate so less vibration (hard to visualise this till youve seen a cutaway in a museum).

[cobrachoppergirl]

@chopperdanny13 Gyroscopic precession does not kill this engine as a viable type, because all you have to do is put two of them (all a Ford Trimotor, for example), on on each wing counter rotating, to cancel it all out. Just like a P-38 does, counter rotates them, though a P-38 uses a straight inline water cooled. But look at the carrier based Corsair, single huge rotary engine, hella lots of power, and feared terribly by the Zeros and for good reason.

[Samwiseification]

@cobrachoppergirl the Corsiar had a radial engine not a rotary

[callmeshane303]

@chopperdanny13

Gyroscopic precession.

There is an easy way to replicate this - get a bicycle front wheel with axle etc., hold the wheel by the axle, and get a friend to spin the wheel as fast as they can, and then try to change the wheel direction i.e. make a hard left or right turn....

[cfmeq]

Texas university? You should know what the word RADIAL means! look it up!

[IronicallyVague]

Amazing craftmanship - I envy the skills & tools needed..

Could you whip up a stirling engine based on the rotary engine idea for me real quick?. Something I always wanted to try but will never have the $ or tools.

Same fixed axis but with a hot air engine insted.

Thanks, I'll wait.... :-P

[bestable]

Rotary Engine or radial Engine ?

[reallywitty06]

This is a rotary engine. Radial engines work like the average internal combustion engine: fixed block & cylinders and a rotating crankshaft. As you can see in this video, the block and cylinders are rotating.

[fowlera7]

is it built to the drawings by l blackmore and if so did you find any errors in the drawings

[206hornet]

Just to give credit to the guy who pulled off this beautiful piece of engineering. If I am not mistaken this is Gerry Younger's engine.

[Error4O1]

Yes it is. Credit was given, and he has posted comments to this vid.

[erickvolpini]

Awwesomee!!!

[newcomer9747]

But the rotor rotates a single fixed axis right? Where does the gyro effect come from?

[Error4O1]

Other than the prop (which all prop planes have), the mass of spinning cylinders produces the gyroscopic effect mentioned.

[myConscious]

@Error4O1

Please, read my previous comments (questions) regarding this engine and tell me whether it is effectively possible or worth a try,.

Thanks

[newcomer9747]

What if you add a balancer to cancel out the vibrations?

[Dystopiologist]

Having the system balanced as much as possible is pretty much a given.

But the balance has nothing to do with the big-time gyro effect - which works at a 90 degree angle, if I remember right.

You say "Up", it says "right"; you say "right", it says "down" - that kinda thing. Try forcing change on a spinning gyroscope (or a spinning front wheel for a bicycle between your hands) to get the effect...

[abulmagd3]

Pretty Fast one

[jayguy173]

vtec it

[Parubhi]

lol...good one.

[greencoupedeville]

To clarify things, the engine in the vid is a 'rotary'. If you're thinking of a Wankel engine, like in a Mazda, it's a 'rotary piston'.

The big problem with rotaries is the gyroscope effect they had. It made the aircraft hard to manoevre, and for a pilot with little training, deadly.

[Wishuey]

Unless I missed it, it doesn`t appear as if anyone mentioned what W.O.Bentley accomplished after WWI. He designed and built the Bentley car from 1919-1931; won LeMans a number of times and went on to design V12 engines for Lagonda. Bentley is now owned by,( horrors!), Volkswagen, while BMW own Rolls-Royce. Who really won WWII?....

[Error4O1]

True, and no, no one mentioned that info yet. Thanks for posting it.

[Triple88a]

sounds like a freaking huge v8.. love it :) nice job

[sb6lb3]

this is the only kind of rotary engine i like, not the wankel, or anyother, just plain ol' radial rotory. and dadood a radial engine has the eninge stay in place, while in a rotory its the opposite.

[Daood416]

Isn't this a radial engine?

[RyuDarragh]

I don't think so, sb6lb3. The two engines would cause chaotic turbulance in the air flow. Just the blades alone might do that, but these are fixed shaft rotating engines where the pistons and cylinder bores rotate around the shaft. It was abandoned fairly quickly when they managed to engineer rotating shaft fixed bore engines.

[cfmeq]

There is a number of planes like that!

[sb6lb3]

you know i wonder how a good a plane would be if it had two engine with each going in opposite direction with both in the same air flow. that would make the centrifugal forces that the engine make cancel each other out and make the airflow more efficient. wouldn't that work?

[simbad307]

That would be a serious technical challenge. The engine spins around the crank, the propeller is fixed to the engine casing, the crank shaft is stationary and fixed to the aircraft.

These were cheap and quick to make in the war, the pilto had to make compensations using full rudder at times.

[jakethemus4321]

Good engine

[Bullettube]

This was a good engine up to a certain horsepower and weight.  A more powerful engine weighed more and thus centrifugal forces really built up, to a point where it could cause the airplane to view right or left. Once 300hp and 400hp non-rotaries were built, the rotary became obsolete.

[simbad307]

That's right. These types of rotary engines were used in the Sopwith's. They killed so many pilots in training because of the forces created by the spinning mass at the front of the aeroplane. They were used because they were cheap and quick to make.

Nice engine.

[Bullettube]

I think BMW made a rotary back in 1915 for German aircraft. The French, Italians and British all tried this type of motor. It's main disadvantage lay in it's use in combat aircraft, but otherwise it worked well because it ran cooler, and thus was more reliable.

[wilzchau]

Why the cylinders will rotate? Who can tell me how does it work?

[94XJ]

As has been stated before, the cylinders rotate around the crankshaft which is fixed. Having so much mass rotating makes the engine a bit smoother without the addition of a flywheel which helped keep weight down.

[TimZZR]

Does any1 know how these rotary engines work?

[Helge129]

The same way a normal engine would work, with one difference: The motor moves, and the axe is fixed.

[Matteo599]

non ho may visto un motore simile.

[cfmeq]

This engine is a Rotary type radial , generaly known as a 'Rotary'!!!! 1917

[dustziggy]

HUH!? If im not mistaken this is a 'radial' engine not a 'rotary'. Rotary's are something mazda make

[Error4O1]

Here's a tip: google Bentley BR2. It's a rotary. Mazda didn't invent rotary engines.

There's also a design called the rotary valve design (also not designed by Mazda, but still a rotary).

[TheDark12]

Err... Mazda uses a Wankel rotary engine. Mazda didn't invent the rotary engine, there are many invented.

[WranglerSlim]

I know, the rotary thing is confusing. The "Wankel" rotary engine uses triangular shaped rotors that follow a wobbling path through an oval-shaped combustion chamber. In WW1, "rotary" referred to an engine whose radially-opposed cylinders rotated around the stationary crankshaft.

[krookedKiller13]

Awesome!

[cfmeq]

Its running on 100 Oct avgas, lube castor oil

not mixed.....Gerry

[scafool]

just one question.

What fuel is it running on?

[briquetaverne]

I don't know how to build any of these machines but I completely understand their principles. Ducati Motorcycles Builds engines with "Desmodromic" driven overhead valves. Less moving parts makes for stronger motors; Have any of you ever thought of incorporating a desmodromic design to Radial/ rotary engines? I suspect their performance would greatly increase.

[TommeyLeeReed]

Nice.. This is my rotary engine.

[siripswich]

Cool, they seems to be much confusion between a rotary and a pistonless rotary engine....thanks for showing me the former.

[rjnerd]

These engines are great fun. They are particularly good at distributing their lubricating oil everywhere. A buddy built one to slightly larger scale, and now has a shroud, not to keep hands from the prop (the prop is larger) but to contain the stuff it slings.

There is a published set of plans out there, Rollie didn't see a full sized one until after he finished his model, so he worked from someone else's drawings.

As to the 9 sets of parts, building the engine was his excuse for getting CNC

[bigdodgeaus]

The real ones threw so much castor oil out that the pilots of ww1 suffered from gastric a lot. Castor oil was used as the lubricant.

[cfmeq]

You are quite right,Gerry did not blueprint the engine, and this engine would not have been built if it were not for the research of Lew Blackmore. However although his book was an excelent guide, as any modeler will say we generaly use our own methods.......Gerry

[simonwass]

Are you the same Gerry? I bow to your skills if you are, seeing the parts dad is building this engine is extreemly interesting. Each part is nothing special (apart from knowing the set-ups needed to make some) but to make 9 sets of identical parts must be a nightmare!

[bangous]

that would be fun to put a mini camera on the end of the prop lol.

[rikuwillkillu]

wow imagin getting ur hand in that

[thedillestpickle]

thats pretty freaking weird, and the fuel gets to the pistons how? that seems so odd. what are the advantages to having an anchored crankshaft? your engine spins around insanely, and you benifit how? no need for a flyweel... ok what else? and again... fuel gets to the pistons... how? lol what a weird idea

[Error4O1]

The pipes going to the cylinder heads are intake headers, there are no mufflers on this engine. So centrifugal forces the fuel/air from the carb at the rear of the engine out to the intake valves. It was an early aircraft motor (1917?), so it's low tech compared to engines from WWII (1945). Basically it was state of the art back in the day. Also, it's not my engine, and the guy running it was who built it.  Awesome model none the less.

[whizbang47]

Chill, dill. The deal was light weight and self-cooling, plus terrific torque and acceleration. Look at the big prop on a Nieuport or a Dreidecker. A 90 horse OX-5 v-8 weighed 400 pounds!

[thedillestpickle]

Wow i have no idea what this is... why is the engine spinning? im so confused

[Error4O1]

It's a model of an aircraft engine from WWI (Bentley BR2) where the cylinders spin around a fixed crank.

[cfmeq]

CORRECTION!!FULL SIZE BENTLEY WAS 230 HORSE POWER. sorry about that

[cfmeq]

What's the differance? basicly a standard radial held by the crank shaft,is a rotary

[depracer]

Tisualize your putting a crank from a small engine into a vise. You obviously can spin the rod assembly around but you can't make the piston assembly 'reciprocate'(Ie this piston assembly does not stop and then reverse its direction). With normal reciprocation the stress on the pin assembly and the rod bearings is very great. There is no need for counterweights on the crankshaft and the crankshaft extremely in weight. This minimized weight and stress evidences very sensible engineering design.

[readmedottext]

Thanks for posting this. I've never been able to see a rotary aircraft engine work.

[SNES85guy]

So how much hp does it produce? I remember the Gnome rotaries being something like 100hp for the WWI planes.

[cfmeq]

full size 135 hp ,this 1/4 scale bentley br2

(1917) about 3HP

[vegasheat07]

Good job thats a cool engine

[cfmeq]

Some of you should look up the word radial in the dictonary....gerry

[cfmeq]

I'ts not a Gnome its a Bentley BR2...Gerry

[Error4O1]

Go wiki "Bentley BR2" (which this is a scale model of).

It's a rotary cylinder, not a rotary piston, engine.

[mrf350]

Do not ever use wikipedia, people like you or me could create an account and modify anything on there,

[Error4O1]

Wiki, google, the public library. Whatever thee preferred KB, go look up Bentley BR2. The fact remains that the BR2 is a rotary cylinder engine. It was probably the pinnacle of that design type. Radial engines (like the Pratt & Whitney Wasp) end up producing more hp by using superchargers and better carb systems. I can't believe people are getting into pissing matches over semantics. The BR2s were called rotary back in the day when people called cancer "The Consumption". Get over it.

[mrf350]

All right I was just stating a fact that Wikipedia sucks ass.

[Error4O1]

np, I'm just tired of folks arguing over what this engine is called. True, wiki does suck ass sometimes, and I'm not saying it's the do all be all repository of knowledge.  My comment was not aimed at you per se, sorry if it was taken that way.

[mrf350]

Hey it's no problem I get that all the time.

[marshallvalvestate]

i think the word you guys should be calling it is a radial engine not rotary, rotary engines are in mazda cars

[oisiaa]

You are wrong. These came way before the Wankel rotary engine (WWI aircraft engines).

[salemcripple]

lol, You just said the same exact thing he did! marshallvalvestate said it should NOT be called a rotary. Rather a radial engine.

[simonwass]

when these engines were built they were called rotary engines, just because wankel called his engine a rotary doesnt make it wrong to call the br2 a rotary, mr wankel is wrong!

[salemcripple]

Yes i relize that, but terminoligy changes over the years. So it realy doesn't matter what it was called when it was built. What matters is the current term used.

[simonwass]

When you make a model of a Bentley Rotary, just because you make it in 2008, it doesnt magically become a Bentley Radial. The simple fact is when the engine was designed, built and used in WW1 it was a rotary engine, just get over it.

[salemcripple]

Yes, they were called rotorys then, they are called radials now. Along with all their bretheren of the same desighn. I was perfectly fine "getting over it". Youre the one that's dragging this out.

[mid186]

They were called rotary engines then and they are called rotary engines today. The distinction between a rotary and a radial is that the rotary has its crank shaft fixed to the airframe and the prop is bolted to the block whereas the radial has its block bolted to the airframe and the prop attached to the crank.

[alanlehman]

Yes, these were always called 'rotary'. They have nothing to do with a Wankel rotary, and they do have pistons.

[90Turbo7m]

thing about rotary.... their less likely to fail then a piston engine... but piston is longer lasting...

[simonwass]

I hope my fathers Bentley BR2 rotary looks and sounds as good (if he ever finishes it!).

You are right with the term Rotary, Rotary fixed crank, radial fixed cyls. If this was how they were described in the 1st WW, then its good enough for me.

[Bergstaller01]

Its a radial engine that rotates :P lol

[umaseti]

i must ask but it says hand made. of course u mean you have access to a machine shop of some sort and you designed it based off your own knowledge.

[Error4O1]

No. I saw this engine at a model expo in Pennsylvania a couple years ago. It was "blue printed", drawn up, machined and fabricated by a Canadian gentleman by the name of Gerry Younger. I was amazed by his work. Parts that I thought were cast were actually machined and worked to look cast. Check the link I posted for the stills.

[simonwass]

I dont believe Gerry Younger actually 'blue printed', drawn up this engine. He may have machined it though. It is the true show of the advanced model engineers skills. It is an existing design (1986 when 1st described) by the Australian Lew Blackmore. You can buy a book with the drawings in.

[gothoaxed]

You are the man!

[shaun928]

@ scarletwingsankh.... u fail.

[Error4O1]

Nope, he's right. The Gnome is a rotary, not a radial. Many websites will confirm this.

[GGigabiteM]

Well technically by todays standards it is a radial engine with a fixed crankshaft (I just call them reverse radials, it makes more sense.) Back then they didn't have Mazda and the Wankel engine so it would have been more correct back then.

There are some differences in how the fuel and oil get to the engine, but other than that the concept is the same.

[Error4O1]

Technically you're right. But,a google for "gnome engine" returned a bunch of sites that refer to the gnome as a rotary. But, after looking at one of the pix of this engine, the builder refers to it as a radial.

[scarletwingsankh]

This is a Rotary not a radial.

[Error4O1]

So true my friend. I'll try to get that fixed. Thanks.

[jezzygirl]

The terms are not mutually exclusive. It is a rotary radial,technically and historically speaking. Radial refers to cylinder disposition, rotary describing the fact that the whole engine rotates. obviously the Mazda and Wankel type rotaries are a whole diffrent genre.

[PiPsQk]

So awesome i love these engines , thanks for posting!

[mike5840]

That's one of the most remarkable things I've ever seen.

Well done!!

[riggerparish]

That is fantastic. Well done!