How strict is the rule for a piston engine ?

[GeoffS]

Re: How strict is the rule for a piston engine ?

How would you arrange the nacelles to avoid flow interference between the wing and nacelle?

Ex: http://ntrs.nasa.gov/archive/nasa/ca...1981009465.pdf

[First time Juke]

Re: How strict is the rule for a piston engine ?

As many have found out, replacing a jet engine's lightweight, powerful turbine with a heavy piston engine to provide the power needed to spin the compressor is actually a step backwards in progress.

I am not going to replace jet engine with a piston engine, but trying to make a scramjet take off as a "primitive jet" with can be turned of and the craft to be propelled as a scramjet without a fan...you know that jet engines allow only 1100 C degree temperatures and thus becomes somewhat ineffective very high speeds ( excluding SR-71 ).

Reusable craft like this could work as a platform to put more "tourists" into the orbit if found profitable etc.

Possibly I am just thinking loud like Cauley did in 1792 when stating how an aeroplane would work...took 111 years before first flight was realised ( I may not live that long ).

[First time Juke]

Re: How strict is the rule for a piston engine ?

1. How would you arrange the nacelles to avoid flow interference between the wing and nacelle?

2."maximum flow" how?

1.Well something looking like Concorde, SR-71 and the NASA X-scramjet seem to work.
2. There is certaing shape in scramjet witch does not like too many fanblades in front of it ( or behind it )...this design minimizes them...all ramjets seem to look like hollow tubes. I think it relates also to the temperatures..more air means possibility to burn ramjet in higher temperature.

[AirDOGGe]

Re: How strict is the rule for a piston engine ?

...2. There is certaing shape in scramjet witch does not like too many fanblades in front of it ( or behind it )...this design minimizes them...all ramjets seem to look like hollow tubes.

Scramjets don't have fanblades my friend.

A ramjet and scramjet are roughly the same thing. The differences are:

--> A ramjet must be propelled through the air at supersonic speeds to ignite and function (mach 2-3 is the norm). The inlet design slows the incoming air to subsonic speeds relative to the engine before adding fuel and burning it to produce thrust.

--> A scramjet (Supersonic Combustion Ramjet) functions likewise but at a much higher supersonic (hypersonic) speed of mach 5 or higher. The incoming air is compressed by ram effect like the ramjet, but does not get slowed to subsonic speed. Fuel is injected into the supersonic airflow and ignited immediately via the spontaneous combustion of a chemical additive.


It sounds to me that what you are seeking is roughly similar to the turbojet/ramjet engines of the SR-71, but you want hypersonic scramjet performance. Sound correct?

If so, then I don't see where a piston engine driving a compressor fan provides an advantage for such a vehicle.


.

[Leo]

Re: How strict is the rule for a piston engine ?

Um...I know this is ALL hypothetical, but Mach 2 around a pylon course?
I would LOVE to see the waiver on that...not to mention the noise complaints!
I seem to remember a quote from an SR-71 driver that a mis-timed turn didn't result in a go around, it resulted in an international incident.

[First time Juke]

Re: How strict is the rule for a piston engine ?

Um...I know this is ALL hypothetical, but Mach 2 around a pylon course?
I would LOVE to see the waiver on that...not to mention the noise complaints!
I seem to remember a quote from an SR-71 driver that a mis-timed turn didn't result in a go around, it resulted in an international incident.

Yes Leo...this hybrid ramjet fan twin would be slightly overpowered to go around pylons..also an international incident could happen if it entered the Reno Stead via space prior to the races.

Airdogge...I meant the blades could be feathered thus allowing the air go tru the tube 95% free of obstacles...still more like a ramjet in function...this is just a wild idea of a selfmade mans aviation dreams ( I am no engineer genious like mr. Cauley ). The effect of the system is more in the "architectural general layout" of parts than in the details of the single engine.

It is all aerodynamics and power to weight ratio if you wanna go really fast.

[shadow]

Re: your answer lies ABOVE /\

or BELOW \/...this is a goofy multi level forum!

http://www.airrace.org/RulesOfCompetition2010-V1-5-30-10.pdf

Jet1, did you even read the two docs you posted? I searched through the latter document (because it's the newest) for 'piston' and 'propeller' and 'propellor' and 'prop'. Those words do not even exist in the document you provided.

Thanks for posting the links, but indeed, my answer does not lie above nor below nor therein.

I'm guessing that there are rules put out by each class regarding their specific class aircraft eligilibility.

I'll go on a hunt to see if I can find them.

Thanks,
Serge.

edit: I see that the first portion of your post you cut&pasted from the website. Without the quotes and attributing the quotation to it's respective source I understood your post to be your own words. Things only became even more confusing when the link you provided did not contain your text. We're on the same page now I think.

[GeoffS]

Re: How strict is the rule for a piston engine ?

Juke, I here are some links about ducted fans that may be of interest:

Ducted Fan Design (Google Books)

An article about adding a ducted-fan to a Cozy Mk IV

Obviously, these are strictly sub-sonic applications, but they may be interesting/useful nevertheless.

Most of the hybrid ram-jet designs use a co-axial layout, with the accelerating engine in the center of the duct, with flow modifiers to bypass air around it in the ram-jet mode:

http://www.aerospaceweb.org/question/propulsion/q0175.shtml

I'm also curious why you want two fans driven by a single motor? A single fan of reasonable size should be able to absorb the power from any internal-combustion (or even gas-turbine) engine you could get, so why complicate things with chain-drives?

I've always wondered if a internal-combustion engine supersonic power-plant could be built from a simple (relatively) ducted fan/compressor with an efficient multiple-shock and diffuser inlet (to slow the free-stream velocity down to low-mach) and a convergent-divergent (Laval) exit nozzle could work. The problems (I think) would be the cross-section at the fan, and how much energy the fan/compressor could add to the flow (not to mention losses throughout the system). It's an intriguingly simple system: diffuser/fan/nozzle - there has to be something I'm missing...

Cheers,

Geoff S.

[First time Juke]

Re: How strict is the rule for a piston engine ?

There's a story by Mark Kallio (HERE) where Hal Dantone (I think I have the spelling correct) was proposing a "steam afterburner" system which used engine exhaust heat to expand water into a vapor and recover thrust....

There was some question then if that would be considered legal... Interesting theory...

I got so far in this that I made a drawing of a 1/12.5 scale P-51H with tubes from engine to scoop ( via fuse ) to see if the heated air will cause ram effect and better cooling in a R/C model. Worth to try at least ( practically model is lighter than usually when I made the ram-air/scoop system hollow and breathable ) . I will not try to lit it or use gas to affect a ramjet phenomenon...but I may put few "chinese new year whistles" to see if it gets some RATO action later. I had made a pencil plans of same model and now when I put in on CAD it looks even better.

[First time Juke]

Re: How strict is the rule for a piston engine ?

Am I anywhere there yet ?

[Bill@Interstell]

Re: How strict is the rule for a piston engine ?

There's a story by Mark Kallio (HERE) where Hal Dantone (I think I have the spelling correct) was proposing a "steam afterburner" system which used engine exhaust heat to expand water into a vapor and recover thrust....

There was some question then if that would be considered legal... Interesting theory...

That sounds bit like the description of the boil off systems we've seen in the past. Rare Bear's even points aft now doesn't it?

[AAFO_WSagar]

Re: How strict is the rule for a piston engine ?

That sounds bit like the description of the boil off systems we've seen in the past. Rare Bear's even points aft now doesn't it?

Hey Bill... how you been doin'?...

Actually the Dantone plan routed the exhaust into the picture, using the heat from same to expand the water into vapor and capture thrust there..

I'm guessing there for sure is some thrust from the Bear's BO system, however negligible/tangible it might be, I *think* the real advantage of the boil off is to completely lose the cooling drag.

If only money grew on trees ey! We'd see some radical stuff to be sure..

[First time Juke]

Re: How strict is the rule for a piston engine ?

If only money grew on trees ey! We'd see some radical stuff to be sure..

Right Wayne...there has to be a foreseeable profit and positive ecological aspect to be sure it pays back the money invested.

I have an idea to make a pistonengined "Learfan" faster and more reliable with a new kinda coupled twinengine...using some of the features of my small pusherfan multiple new ideas..and some never before seen aspects.

[First time Juke]

Re: How strict is the rule for a piston engine ?

I'm guessing there for sure is some thrust from the Bear's BO system, however negligible/tangible it might be, I *think* the real advantage of the boil off is to completely lose the cooling drag.

But if you bring more weight...how much speed is lost by that system ?

Here is once more the system how I am going to make my P51H model use the scoop to suck more air from the engine room to cool it of.

The maroon lines indicate the air-flow. 2 tubes are in the fuse.

[JET1]

sonny boy...

why no I didn't---I was merely trying to point yall in the right direction to do your own investigation.......

Jet1, did you even read the two docs you posted? I searched through the latter document (because it's the newest) for 'piston' and 'propeller' and 'propellor' and 'prop'. Those words do not even exist in the document you provided.

Thanks for posting the links, but indeed, my answer does not lie above nor below nor therein.

I'm guessing that there are rules put out by each class regarding their specific class aircraft eligilibility.

I'll go on a hunt to see if I can find them.

Thanks,
Serge.

edit: I see that the first portion of your post you cut&pasted from the website. Without the quotes and attributing the quotation to it's respective source I understood your post to be your own words. Things only became even more confusing when the link you provided did not contain your text. We're on the same page now I think.