How strict is the rule for a piston engine ?

[First time Juke]

Internal combustion engine.

How about if the concept was slightly manipulated ?

I mean if I had a V-8 running fans/props in a tube creating pressure in the tube and then ignited some fuel in the tube ( kinda like reversed adi )..I assume this kinda vehicle could go well beyond mach one...and be more effective than a traditional jet and whole lotta more simple.

Would this kinda piston engine aided "scramjet" be disqualified in Reno races ?

Just a tought.

[AirDOGGe]

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

I assume you mean the Unlimiteds. Propellers (of any quantity) are the requirement. No ducted fans or enclosed props allowed.

And it's not INTERNAL COMBUSTION engines that are allowed, since turbines and rocket engines also fit that description. It's reciprocating (piston) engines only.

I suspect Wankel rotaries are banned too, but not sure on that one. It may just be that no existing Wankel engine is competitive enough to race against the big WWII era engines...not yet anyway.

And certainly no propulsion system that creates augmented jet thrust, such as the makeshift afterburner you described.


Now I am wondering....would a 16-blade UNDUCTED fan powered by a recip quality as a propeller? Hmmm...


.


P.S....By the way, The Caproni company already tried your piston/jet concept in the 40's with the Campini N.1 (<-- click link for details). It didn't work very well, proving heavier and less efficent than a standard jet turbine.

In 1931 Ing Secondo Campini submitted a report to the Italian Air Ministry, regarding the use of jet engines in aircraft .His design which he called the "Thermojet" consisted of a 900 hp Isotta Fraschini L.121/R.C.40 piston engine driving a compressor which used two ducted fans to compress the air and one fan to direct the flow of air, a ring of injectors introduced fuel and the air/fuel mix was burnt to give thrust.

[JET1]

&quot;piston powered propeller driven...&quot;

The Unlimited Class is open to any piston-driven aircraft with an empty weight greater than 4500 pounds [the weight restriction was added in 2005]. Aside from a very few "scratch-built" aircraft, the Unlimited Class has generally been populated by stock or modified WWII fighters, the most-often-flown types including the P-51 Mustang, F-8F Bearcat, and Hawker Sea Fury. Aircraft speeds in the Unlimited Class reach 500 mph.

http://www.airrace.org/RulesofCompetition2006.pdf

Internal combustion engine.

How about if the concept was slightly manipulated ?

I mean if I had a V-8 running fans/props in a tube creating pressure in the tube and then ignited some fuel in the tube ( kinda like reversed adi )..I assume this kinda vehicle could go well beyond mach one...and be more effective than a traditional jet and whole lotta more simple.

Would this kinda piston engine aided "scramjet" be disqualified in Reno races ?

Just a tought.

[AAFO_WSagar]

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...

[rampking]

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

Sounds like you are talking about something like this:
Caproni Campini N1
Italian Radial engine aircraft with a variable ducted fan.

http://www.youtube.com/watch?v=nYjswpH2lVc

[First time Juke]

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

I assume you mean the Unlimiteds. Propellers (of any quantity) are the requirement. No ducted fans or enclosed props allowed.

P.S....By the way, The Caproni company already tried your piston/jet concept in the 40's with the Campini N.1 (<-- click link for details). It didn't work very well, proving heavier and less efficent than a standard jet turbine.

Ok ok !

I had not a Campini N1 in mind, but glad you brought it up. I think this pretty much clears it.

I had 100 times more simpler fan/propulsion technology in mind that could make scramjet flyable also at lower speeds for landing and take offs. Scramjet/ramjet off it could also glide 1/50 - 1/100 ( with excellent LD ) if not maintain a moderate cruise speed.




BTW; Happy mid-sommer !

[First time Juke]

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

Sounds like you are talking about something like this:
Caproni Campini N1
Italian Radial engine aircraft with a variable ducted fan.
http://www.youtube.com/watch?v=nYjswpH2lVc

I am happy you did not suggest this; http://en.wikipedia.org/wiki/Henri_Coand%C4%83

[shadow]

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

No ducted fans or enclosed props allowed.

I was under the impression the rules stated piston-powered and min weight of 4500lbs empty as the only restrictions.

Is there some official RARA rules where you've read about further restrictions?

Thanks,
Serge.

[JET1]

your answer lies ABOVE /\

I was under the impression the rules stated piston-powered and min weight of 4500lbs empty as the only restrictions.

Is there some official RARA rules where you've read about further restrictions?

Thanks,
Serge.

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

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

[GeoffS]

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

I had 100 times more simpler fan/propulsion technology in mind that could make scramjet flyable also at lower speeds...

I'm not sure I understand exactly how your design differs from the motorjet/thermojet engines in the Caproni Campini N1, MIG I-250, Su-5, Tsu-11, and others.
Can you post a simple diagram of what you are talking about?

I'm particularly interested in your comment about a "scramjet". Are you proposing to use the fan/compressor to generate a supersonic flow into/over the scramjet to allow it function when the airframe traveling at subsonic speeds?

Cheers,

Geoff S.

[Leo]

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

As I remember (I will look it up tonight) the Japanese had a version of the Ohka flying bomb that was powered by a JET engine, said engines compressor being powered by a small piston engine, kind of a hybrid techology bridge thing. Not to be confused with the built-in starter engines in the Me-262.
Sounds kind of similiar.

[AirDOGGe]

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

I was under the impression the rules stated piston-powered and min weight of 4500lbs empty as the only restrictions.

Is there some official RARA rules where you've read about further restrictions?

Thanks,
Serge.

I didn't read it, but over the years I had always heard "pistons and propellers" as the primary Unlimited requirement. I could be mistaken.

[First time Juke]

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

I'm not sure I understand exactly how your design differs from the motorjet/thermojet engines in the Caproni Campini N1, MIG I-250, Su-5, Tsu-11, and others.
Can you post a simple diagram of what you are talking about?

I'm particularly interested in your comment about a "scramjet". Are you proposing to use the fan/compressor to generate a supersonic flow into/over the scramjet to allow it function when the airframe traveling at subsonic speeds?

Cheers,

Geoff S.

I was thinking the v-8 would indeed both give speed and compression and could be feathered when scramjet starts to operate at optimal conditions at over mach 1 and no need for compression of the fan is needed.

My design features wing buried chains to propel fans on two nacelles. V-8would be in a fuse aft pilot. This would yield maximum flow through the ram tube ( unlike in a turbofan ).

X-43 ( or was it 45 ) tales they tell it is hard to imagine how it works since it only works at high speeds. Lite supersonic small V-8 powered plane would possibly need to fly alone too without the ram effect to be effective as a mean of potential apu to assist the scram jet.

I mean the scram would possibly need 200 mph airspeed or runway speed to lit before the tube airflow reaches mach one.

[AirDOGGe]

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 mean the scram would possibly need 200 mph airspeed or runway speed to lit before the tube airflow reaches mach one.

A SCRAMJET *(Supersonic Combustion Ramjet) requires supersonic air coming into the front of the engine to operate properly. Most I've seen need to be propelled to mach 2 or mach 3 before ignition.

I think you mean "Ramjet".

[GeoffS]

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

My design features wing buried chains to propel fans on two nacelles. V-8would be in a fuse aft pilot.

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

This would yield maximum flow through the ram tube ( unlike in a turbofan ).

"maximum flow" how?

I think you mean "Ramjet".

That sounds like the right term, although IIRC even a ramjet doesn't start functioning efficiently until you get to well over mach 1.