Engine discussion ?

[First time Juke]

I just figured a pretty straight forward engine type to propel the future racers at pretty cheap price.

Two V-8s back to back propelling a contra prop ? Would that be enough power to make a ( very ) small racer go 500 mph + ?

[First time Juke]

Re: Engine discussion ?

Those F-1 car engines do 800 ps a piece...so 1600 hp..in a very compact size ( and weight ) + small consumption...right reduction and voila....perhaps a perfect ( torque free ) engine for an unlimited racer.

[AirDOGGe]

Re: Engine discussion ?

The F1's get their power by using small displacement engines turning at incredibly high RPMs. Can you imagine what a super-sport plane would sound like with the powerplant doing 14,000 rpm's? Would the high ratio reduction gearing necessary to get the rpms down to prop speeds handle the vibrations?

In addition, a tandem is sending the power from the rearmost engine through the crankshaft of the front one. You think controlling torsional vibrations of a single crank is bad? Try two of 'em.

But I guess a tandem can be done. The Macchi MC-72 (world's fastest seaplane) used a tandem V-12 arrangement, didn't it?

(Googling...)

Yep. Here it is, complete with a picture of the engine(s). I don't know if they shared a common crankcase or crankshaft though.

http://www.aviationtrivia.homestead.com/MC72.html

.

[mary robey]

Re: Engine discussion ?

Didn't the XP75 Eagle by Fisher Body {GM} have contra props with 2 V12 Allisons behind the pilot. Lots of problems but it did fly at the Cleveland,Ohio airport during testing.
Mary

[First time Juke]

Re: Engine discussion ?

Heinkel He-119 and He-177 Greif had also paired engines.

http://en.wikipedia.org/wiki/Heinkel_He_177

I think two V-8s would be way smaller in space need than twin V-12s ...the angle in the V form is decisive here..even if their proportional size was the same.

Seems that the DB-610 overheated quickly and gearbox troubles in the one prop system were common.

Also Napier Sabre was a 24 cylinder engine but an H-type..also prototypes of that overheated quikly.

Those are the problems that has to be solved.

What I see as a big advantage is that if one engine looses a piston the other keeps going..those engines and a prop would be a unit of their own..albeit being close together..this has never been even tested before..as far as I know. Maybe it is not as problematic as those predecessors in the first place ?

[First time Juke]

Re: Engine discussion ?

The F1's get their power by using small displacement engines turning at incredibly high RPMs. Can you imagine what a super-sport plane would sound like with the powerplant doing 14,000 rpm's? Would the high ratio reduction gearing necessary to get the rpms down to prop speeds handle the vibrations?

In addition, a tandem is sending the power from the rearmost engine through the crankshaft of the front one. You think controlling torsional vibrations of a single crank is bad? Try two of 'em.

But I guess a tandem can be done. The Macchi MC-72 (world's fastest seaplane) used a tandem V-12 arrangement, didn't it?

(Googling...)

Yep. Here it is, complete with a picture of the engine(s). I don't know if they shared a common crankcase or crankshaft though.

http://www.aviationtrivia.homestead.com/MC72.html

.

AirDOGGe,

Thanks for your input.

I am not talking about tandem configuration.

One V-8 would be turning a smallish 2 bladed prop and the other also geared through a reduction almost similar ( mirror image ) size prop to opposite direction. It would naturally have to be vibration free. Gearbox ( reduction but no box ? ) would also have to be really close to the paired engines ( if not partially in between them ). This is the task also..to make it dependable and vibration free. At least firewall can be sturdy in size albeit not as huge as in a single Merlin.

RPMs would be naturally awful high and noisy..possibly a neat muffler can be introduced as and if the project would go on. Also the engine might be tuned for lower rpm and having more torque...reduction would be in any case adjusted to the right prop rpms.

[First time Juke]

Re: Engine discussion ?

I was searching the internet..and one dude was about to make himself a flat V-8 for a car to avoid vibrations...I think a pair of those would be ok ?

More about V-8s here;

http://en.wikipedia.org/wiki/V8

A Mopar Hemi produces 425 hp and 850 hp doubled..without enhancing..not bad. Used in Corvette etc.

[First time Juke]

Re: Engine discussion ?

Next I'll try to prove why a pair of smaller V-8s could be better than a RR Merlin V-1650

http://www.unlimitedexcitement.com/Pride%20of%20Pay%20n%20Pak/Rolls-Royce%20Merlin%20V-1650%20Engine.htm

Rolls-Royce V-1650-9 specs from the insert;

Weight 1,690 lbs
Power 1735 bhp @ 3000 rpm 66" boost




Here is the RS27 V8 by Renault

http://www.sportnetwork.net/main/s208/st110829.htm

Weight 211 lbs
Power 800-950 bhp @ 14000-23000 rpm



Ok let us say for aeroengine a 750 hp would be enough to be on the safe side.

Lets make a small Do-335 type pull push design ( original flew 775 km/h~481 mph ) cleaner without guns etc ( clean could mean a supercharger airintake in the spinner through a hole in the prop shafts for the front engines..for instance). Two engines at the back and two at the front weighing 844 lbs and producing 2800 hp.

This is 1000 hp more at more than half the weight compared to boosted RR V-1650 !

A tractor layoyt racer could have two of these units in tandem..with same power output and weight, but with just one unit 422 lbs and 1500 hp.

Tractor layout kite with this engine unit would hardly weigh more than 2000 lbs..this would yield an unheard power to weight ratio of 1,6 kg / hp. It would be nearly triple of any WW II fighter and double of any regular piston racer up to now.

At 3000 lbs racer it would be 1,1 kg/hp, thus almost double power to weight ratio of the Heinkel He-100 V8 of 1939 which did 460+ mph.
Ernst Heinkel estimated he could make a piston fighter to go 545 mph at 0,8 hp/kg.

Even @ 600 hp per V8 and weighing 4000 lbs this new kinda lite racer would beat Heinkels last 545 mph mover by 10% in power to weight ratio vise.



Ok any comments on this please ?

[h34race]

Re: Engine discussion ?

Hey the falconer v12 is already to do what is needed and I think it has 1200hp injected and that is a mild version just wanted to put my two cents,I wish thay would test more diesel power already make big HP and torque at low rpm I just don't know if thay make a light enough verison to make the CG work any alum diesels out there?? thanks

[First time Juke]

Re: Engine discussion ?

There is indeed Falconer V-12 and a Thunder Mustang to prove that small size goes a long way.

Falconer produces 640 hp and weighs 980 lbs with prop and reduction + other gizmos.

http://www.thundermustang.com/falconer.htm

2x8 is sixteen and 2 x 800 hp is 1600 hp..it is 1/4th ( 960 hp without injection ) more than Thunder Mustangs Falconer. Older V10 F1 car engines were close to 1000 hp, but they blew often with a large fireball..no one wants that to happen in the air.

I am pretty sure with all reduction and prop etc this paired V-8 is close to 800 lbs with firewall and other gizmos. That CG point is very good also.

I guess this could be a dead end. Just food for the thoughts anyway.

[First time Juke]

Re: Engine discussion ?

Thunder Mustang gross weight is 3200 lbs and with 640 hps it gains a 0,44 hp/kg power to weight ratio. Pretty close to average WW II piston fighter.

This is the fastest kit plane and a remarkable achievement as such.

http://www.thundermustang.com/index.html

[First time Juke]

More twist to this subject !

Hi !

Since several folks seem to have been interested about this 2 x V8 subject. I like to add little bit more.

Anybody know if it is ok to slant a V8 90 degrees ?

If it is ok then what can one install between the l l positioned V8 engine blocks ?

Damn right a nose gear could be housed there...and you have a tricycle landing gear, which means better visibility in taxiing etc.

Any interest on this ? or is this totally ?



Happy Easter !



rgds,

Juke

[Stevey]

Re: Engine discussion ?

Hey, I'm new to this board but have been designing a plane for the reno air races for the last few years. I doubt it will ever happen as I dont have the money to make something like that happen. But I was going for sports class. I see your going for unlimited. I dont know much about airplane engines, Im a car engine kinda guy. Are there carbureted airplanes? If so why not run a supercharged 572 cubic inch hemi? Dump some money into it and you can get some crazy high power without having to have a lot of rpms. Having said that you would still have to have a gear reduction I'd imagine. If Im correct the average propeller can only make thrust up to about 7000rpm then the tips of the blades attempt to go supersonic. You should have no problem making the same amount of power as some of those WWII fighters. Although you may have to go up in the 600's for cubic inches. Then the engine will also be quite simple to work on in comparison to some of the other fuel injected "wonders" of today. Ill give what you said a few more thoughts and see what I can actually come up with. Are you just toying around or is this something youd actually like to build? I dont understand where people get the money to air race but it must be quite a wealthy comunity {no offence meant just a jealous observation}, please let me in on your secrets lol.

Steve

[First time Juke]

Re: Engine discussion ?

Stevey,

Quite frankly; I think there has to happen a small scale miracle before I get the backing for this kite for real.

At one stage a gentleman from Norway offered two unused Mossie engines still in wraps for the TS II ( pic in my avatar ), but not for free.

There was an excellent prototype for this kinda racer..the Tsunami...with a V tail and tricycle and double independently turning Hemis ( or what ever flat v-8s ) I think this ( still smaller than a Tsunami ) might really have a change to brake 540 mph mark.

Plane doing these speeds and me being 44 years old...I think I might run out of time before any of my planned plane gets a change to fly.

These for now are pure fantasies for me, but you never know, if some sugardaddy with lotsa spare money appears on the scene like Randy " Hacker " Haskin once put it.

With two Hemis this would be more in the reach than the Merlin racer I have been dreaming/designing between 1989-2003. I mean lighter engine putting the same if not more hp:s..what else does one need...for an idea..to overcome a obstacle..in order to reach the goal of piston engined racer absolute speed record.

Stevey...are you sure a single Hemi would propel a man beyond 540 mph ? Rare Bear had 4500 hp:s to go 528 mph. With an inline engined kite you'll definitely need more than 1/1 hp/kg still. It would have to be nearly Bede sized rocket !

I think I am still doing this to keep myself sane...like some do crosswords...you know what I mean ?

I would have to employ a real phd aerodynamist to work with me, a pilot, an outstanding crew to build the plane and tune it and a windtunnel + 5 years and 20 million dollars to do it...I miss all of that, but they exist somewhere around this tube that I am staring at.

Eric A. has same dream with his pusher...the Dart...will any of these ever fly... I hope so.

[Stevey]

Re: Engine discussion ?

Well thats what I was wondering, where does everyone come up with the money? I had an offer to fund me for my sport class IF I built the plane myself. In other words hed pay for materiels, at the time I was younger and wouldnt take on such a project. If I knew if the offer was still open I may have reconsidered. The porblem is, it's basically impossible to make the money back and it ends up being a big hole for money. Unless you were to make a small scale company building the aircraft {as 5 need to be built for sport class}. Even then you would have to sell a lot of aircraft to get your money back!

I dont believe it would cost me that much to build this plane and get it in the sky and operating BUT the problem would be the fact that I would have to build at least 5 air frames, eerrr "kits". The plane I have been designing seems to have a good chance at some very high speeds, I have started building models to put in a minature wind tunnel I built along with bigger models to fly as an rc plane. Hopeing this will bring to light any aerodynamic problems.

Sorry, Im stealing your thread. I do believe a single engined aircraft with a high displacment hemi could propel AN aircraft to 540mph. But I know it wouldnt be able to propel something the size of Rare Bear to 540mph. If you are planning on unlimited class {not sure minimum weight?}, you could continue with your plan. Or you could follow the trend and drop one huge powerplant up front. Personally Id try and exhaust all of the "normal" forward mounted engine possibilities simply because its tried tested and true. You wont know any possible aerodynamic effects of having 2 props until you try it and by that point it may be too late. My approach has always been 1} Lower as much drag as possible 2} Drop as much weight as possible 3} Make as much power as possible. I have never looked into any radical air frame changes as you are considering. Having said that though, You may be on the right track as there are always some type of technilogical breakthrough's when people go off the beaten trail. I do know that some hemi's in funny car's CAN make up to 2600hp, but I cant imagine they are the most reliable engines in the world. What weight would you be looking at? What hp to kg ratio? What class? Unlimited?

I do believe your goal can be achieved but if I were you I wouldnt be looking for a pilot, crew, aerodynamicist etc. If you are honest to god serious I would get my pilots licence {if I didnt already have them}, it will teach you alot about plane characteristics etc and youll be able to get in flying time {some places rent airplanes for lessons or just logging hours, no need to buy one} and by the time your finished your plane youll be ready to get in the cockpit. Then Id look into taking an online course in aerodynamics {assumeing you dont already have one}, you can take it on your own time it costs minimal $$ and youll learn alot. You will then be able to come up with the piliminary design yourself, then take it to your aerodynamicist to improve. That will save time and money and you will learn lots. Then Id look into construction methods, think you can undertake it alone? Yes? Great go for it. No? Then hire a couple hands to help but you can be there to cut metal or clean tools etc. The more time your there cleaning and helping set up {even helping work?} the less time your paid hands are required. I would only employ them for the times I NEED them, finish work can be done alone {smoothing work, primeing, etc}. Then youve got a plane that you {your now a pilot!! lol} can go test fly and improve on until the air races! Either way Id suggest at least making a hobby wind tunnel, there are plans on the net and if your interested in it its a lot of fun! Sorry if I stepped on any toes, just saying what I would do.

I will continue to check in on this thread but you can always reach me at steveyb4342@hotmail.com {that goes for anyone on this board}.

Thanks Steve